Conference 7.286::space

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From: [email protected]
Newsgroups: sci.space.shuttle
Subject: HST status report excerpt forwarded
Message-ID: <[email protected]>
Date: 30 Apr 90 21:22:56 GMT
Organization: PBS:Public Broadcasting Service, Alexandria, VA
Lines: 20

"At approximately 10:25 p.m. EDT last night [Sun.], the orbital verification
team sent the last in a series of commands that overcame an apparent jam in
one the Hubble Space Telescope's two high gain antennas, which had prrecluded
the use of the antenna system since Friday morning.

 At 9:50 p.m. controllers in the Space Telescope Operations Center had started
sending the commands that gingerly recentered high gain antenna #2 relieving
stresses previously detected in the gimbal assembly.  Successful centering of
the antenna marked a major milestone in the process of recovering use of the
high gain antenna system."

(background paragraphs deleted)

"Analysis revealed that one of the components of the high gain antenna system
was apparently rubbing against the gimbal system power cable harness causing
friction, which caused gimbal system torques to build beyond preset limits.
...(etc. deleted)."

Thought everyone on the net would like to know, it appears HST is going to be
AOK.  No need for house calls, either.

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From: [email protected] (Peter E. Yee)
Newsgroups: sci.space
Subject: NASA Headline News for 04/30/90 (Forwarded)
Message-ID: <[email protected]>
Date: 30 Apr 90 21:11:46 GMT
Sender: [email protected]
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
Lines: 77

-----------------------------------------------------------------
Monday, April 30, 1990                Audio Service: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Monday, April 30...

<News about Discover's touchdown edited out...>

Now five days on its own, the Hubble Space Telescope is in full 
communication with the control center and out of safe mode 
status.  

Demonstrating the ability to recover from safe mode status once a 
situation was understood, analysts confirmed from the data 
recently dumped from two of the three onboard tape recorders what 
actually happened to the high gain antenna when it kicked into 
safe mode.  As the high gain antennaes are technically healthy, 
the problem with high gain antenna number two was due to a simple 
cable in the way of free movement.  Early this morning, the 
problem was reported to have been corrected.

As engineers poured over the data, one control center engineer 
went to a toy store, purchased an assembly kit consisting of 
plastic sticks and joints building a model of the antenna gimbal 
assembly with the components and a piece of lamp cord.  The team 
used the model to help visualize the problem.

Analysis revealed that one of the components of the high gain 
antenna system was rubbing against the gimbal system power cable 
causing friction.  This caused gimbal system torques to go beyond 
preset limits, triggering the spacecraft support systems computer 
to place the telescope in safemode.

The anticipated new science to come once the Hubble is fully 
awake is what experts have in mind.  The first possible time for 
light pictures will be approximately one week.  The next in line 
of the great observatory series for launch this year include the 
Astro-1 payload on space shuttle Columbia planned for May 16 as 
well as the Gamma Ray Observatory scheduled for November 1.

                            ********








----------------------------------------------------------------
Here's the broadcast schedule for Public Affairs events on NASA 
Select TV.  The following times listed are Eastern.


Wednesday, May 2.....

                    10:00 A.M.       STS-35 Astro-1 mission and
                                     science briefing at Kennedy
                                     Space Center.



----------------------------------------------------------------
All events and times are subject to change without notice.
These reports are filed daily, Monday through Friday, at 12:00 
Noon, EDT.  This is a service of the Internal Communications 
Branch, NASA Headquarters.

Note 480 in the Astronomy conference also talks about the Hubble Space
Telescope.

- dave

Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/01/90
Date: 1 May 90 22:20:47 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      HUBBLE SPACE TELESCOPE UPDATE
                              MAY 1, 1990
 
     The Hubble Space Telescope project reports that data is being
analyzed from two series of tests run recently.  Tests were performed
on the two high gain antennas to map out safe regions where both high
gain antennas can safely operate without obstruction.  The next step
for the team is to moderate ground and flight software to limit the
travel of the high gain antennas to those regions that have been
mapped.  The Hubble team also is getting preliminary information on
the alignment of the three fine guidance sensors by pattern matching
star fields through the optics of the telescope. 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

    Probably a dumb question, but........
    I keep hearing on the news how the "novice" team operating and checking
    out the HST will take moths to do so, etc, etc.  The point being about
    the what sounds to be the presence of inexperience and learn as we go.
    I guess I thought that with the long delayed launch much was learned
    about how to "handle" HST once it was in orbit.  Much was learned
    relative to software control and debugging.  Surely there was time for
    an incredible number of man-years of experience and simulation.  From
    the news reports it "seems" like either than wasn't true, or else there
    was truely an incredible amount of unknowns that simulations couldn't
    have forseen.  
    
    This isn't intended as a negative note, just trying to understand. 
    Anyone care to enlighten me?

Based on the various reports I've been reading, it seems there is a finite
limit on what simulations and tests on earth could reveal about the behavior
of the scope - please remember that the most senstive and accurate pointing
device that man has ever created weighs 12 tons and zips around the earth
380 miles up.

If you put into perspective that the orbital verification phase of the project
was to last several months, you can see that from Day 1 nobody expected this
instrument to be a "point and shoot" device -- the fact that they are having
even more problems seems almost par for the course.

While I can't deny that the delay allowed the team to practice more, at least
one of the major tasks recently accomplished during the delay was the
reprogramming of the *scheduling* software (the slotting and pointing schedule)
as opposed to the flight control software.

On the surface, it would seem that a lot of the recent problems (solar array
deploy, hi-gain antenna problems) would have been things that were caught
a long time ago.  Still, how something behaves at 1G and how it behaves in 0G
are bound to be different, and not perfectly simulatable (if I can use such
a word) (e.g., the door opening jarred the scope more than expected, forcing
it into a "safing" mode - which takes time to get out of).

The telescope operators are being *very* cautious at this moment.  There are
limits set on the various mechanical parts of the telescope and sensors to
watch them.  If devices don't work according to the plan, then it isn't
necessarily because they are broken - the plan might be wrong.  The "quick
fix" mentality of a lot of people watching this makes it seem a lot worse
than it is.  Over time (months and years) they will learn how this thing
*really* flies and be able to push their initial limits a bit.  Until then,
they can take all the time they want (as far as I'm concerned).

- dave

  The 1st flight of a major aeor-space system is always a test situation.
Remember that the 1st few Saturn Vs were not even maned. The 1st 4 flights of
the Shuttle were considered to be test flights. Aero systems like the B-2,
Boing 747, Piper Cub etc. always involve lots of test flights before the system
is considered ready for production. And all those systems were simulated on the
ground before they flew (well maybe not the Cub).

  If the 1st (and only) HST is done testing in a couple of months and is ready
to go that will be a remarkable accomplishment. 

  George

... someone forgets to throw a switch...  Sigh!

-----------------------------------------------------------------
Wednesday, May 2, 1990                Audio Service: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Wednesday, May 2...

The Hubble Space Telescope continues to operate in good health 
and in full communications with the Space Telescope Control 
Center.  During a Pointing and Safemode Electronics Assembly 
self-test mode last night at 7:00 P.M., engineers overlooked 
activating an aperture door inhibit switch.  As a result, the 
motion put the safecraft into safemode status.  Operating as it 
should, the computer commanded the door shut.  This morning, the 
HST was brought completely out of safemode, the door is open and 
the spacecraft is operating normally.
                            ********
Analysts are also reviewing Hubble Space Telescope data received 
last night from two high gain antenna tests in order to map out 
safe operating regions where both antenna can function without 
obstruction and then adapt the software to those specifics.  
Deputy project manager at Marshall Space Flight Center, Jean 
Olivier is optimistic this will not prevent any scientific work, 
merely postpone an activity to "tomorrow rather than today."

From: [email protected] (Rick Ellis)
Newsgroups: sci.space.shuttle
Subject: Hubble's orbit - What is it?
Date: 1 May 90 22:35:59 GMT
Organization: Universal Electronics Inc. (Gateway)
 
    In a message of <Apr 26 21:14>, Craig Alexander ([email protected]) 
writes: 
 
    > What kind of orbit is the Hubble in? I would assume a polar orbit
    > of some kind with the telescope's eye away from the Sun. Is this
    > correct? 
  
    This should answer your question:
 
    STS-31 FLIGHT DAY 3
    HST REALTIME STATE VECTOR 1
 
 The following Hubble Space Telescope vector for the flight of
 STS-31 is provided be NASA Johnson Space Center Flight Design and
 Dynamics Division for use in ground track plotting programs.  The
 vector is valid for a Mission Elapsed Time (MET) of 2 days,
 5 hours, 10 minutes.
 
 Liftoff Time: 1990:114:12:33:50.953
 Liftoff Date: 4/24/90
 
 Vector Time (GMT) : 116:17:43:50.952
 Vector Time (MET) : 002:05:09:59.999
 Orbit Count : 34
 Weight : 23905 LBS
 Drag Coefficient : 2.0
 Drag Area: 700 SQ FT
 
 HA=333.610 NM
 HP=330.056 NM
 
      M50 Elements			     Keplerian Elements
 -----------------------		 --------------------------
 X    =  2145540.8     FT		 A	    = 3778.3367 NM
 Y    = -20670127.9    FT		 E	    = 0.001133
 Z    =  9696397.2     FT		 I  (M50)   = 28.32616	DEG
 Xdot =  23694.368281  FT/S		 Wp (M50)   = 52.53412	DEG
 Ydot =  4958.474745   FT/S		 RAAN (M50) = 215.97313 DEG
 Zdot =  5339.318928   FT/S		 N	    = 10.48141 DEG
					 M	    = 10.45780 DEG
  
 Mean of 1950 (M50)   : Inertial, right-handed Cartesian system whose
 Coordinate System	origin is the center of the earth.  The epoch
			is the beginning of the Besselian year 1950.
			X axis: Mean vernal equinox of epoch
                        Z axis: Earth's mean rotational axis of epoch
			Y axis: Completes right-hand system
 ===
 end of data
  
--  
Rick Ellis
....!{dhw68k,zardoz,lawnet,conexch}!ofa123!rick                            
 [email protected]
714 544-0934 2400/1200/300

  For those of us who don't speak orbital mechanics, could someone fill us in
as to how far north/south in latatude the scope would travel in a typical
oribt? Also, about how many degrees difference between the plane of it's
orbit and the plane of the earth's orbit?

  On the HST door; is it ment to be opened and closed often or is that suppose
to be an launch/return/emergency type of operation?

  George

I don't know this for certain, but I'm fairly confident that it is kept open
except for extreme situations (e.g., safe mode, retrieval, deployment).

I believe you will be hardpressed to find any significant amounts of time
when the scope will not be in use - so there will be little reason to close
the door.  This is just a guess though.   They might close it if they have
to slew the scope past or near the sun  -- but I would have thought they would
plan around that.

- dave

As long as I'm here...

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From: [email protected]
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.top
Subject: Hubble Space Telescope antennas adjusted; glitch investigated
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 1 May 90 21:12:49 GMT
Lines: 62
Approved: [email protected]
Xref: shlump.nac.dec.com clari.tw.space:152 clari.news.aviation:257 clari.news.top:326
ACategory: usa
Slugword: telescope
Priority: major
Format: regular
X-Supersedes: <[email protected]>
ANPA: Wc: 671; Id: a2580; Sel: na--a; Adate: 5-1-505ped; Ver: ld
Codes: ynssrxx., ybtarxx.
Note: (complete writethru -- new glitch found in gyroscopes)


	GREENBELT, Md. (UPI) -- NASA engineers Tuesday tested the Hubble
Space Telescope's antennas and pointing system and hit yet another
glitch -- this time in gyroscopes used to position the giant orbiting
observatory.
	``They really don't know what the problem is,'' said NASA spokesman
Jim Elliott. ``But they don't think it's serious.''
	The problem occurred at about 1:13 a.m. while engineers at the
Goddard Space Flight Center were testing the $1.5 billion telescope's
three ``fine guidance sensors,'' which are used to locate and lock onto
celestial targets.
	``All three found stars and transmitted their locations to Goddard
for further identification by astronomers on the ground,'' a NASA
statement said.
	But while conducting the tests, engineers ``ran into what they
called a `frequency anomaly' while they had two of the (sensors) in a
locked position,'' the statement said.
	At the time, the spacecraft's four gyroscopes, which are used to
help determine the telescope's position, were operating at a ``low-rate
(observer mode),'' the statement said.
	``When the frequency anomaly developed... it triggered the
spacecraft's safemode body rate test'' -- a test of whether the craft is
safe -- ``and switched to the higher rate mode,'' the statement said.
	``When the gyros switched, the engineers terminated the activity.
They are investigating the cause of the anomaly today,'' the statement
said.
	The glitch occurred just after technicians completed nearly five
hours of tests on the telescope's two ``high gain antennas'' as part of
an effort to prevent them from becoming jammed again.
	The 12-ton telescope was placed into orbit last week by the space
shuttle Discovery for a 15-year mission to search for clues about the
birth, structure and destiny of the universe by studying planets, stars
and galaxies more clearly than ever before.
	Problems in the initial steps of slowly starting the telesopce
forced NASA about a week behind schedule in the eight-month process,
delaying the historic first image of the heavens until the weekend at
the earliest.
	The most significant problem involved one of the telescope's two
``high-gain antennas,'' two parabolic dishes mounted on 15-foot masts on
each side of the telescope to beam critical scientific data to
astronomers on the ground.
	Using computers and a makeshift model made of Tinkertoys and a lamp
cord, engineers Sunday determined one of the antennas had jammed when a
counterweight hit a loose power cable.
	After freeing the antenna, technicians moved both antennas around
to determine exactly how far they can go before coming into contact with
nearby power cables.
	Programmers planned to re-write the computer program that runs the
antennas to permanently limit the movement of the antennas, said Jim
Moore, a telescope project manager.
	The changes will probably restrict movement of each antenna 10
percent to 15 percent, Moore said. But he stressed that would not have a
significant impact on the telescope's ability.
	``We really don't interpret this as a constraint at all to
operations. The systems really is way overdesigned,'' he said. ``There
realy will be no impact on the planned observing program.''
	In addition to investigating the gyroscope glitch, engineers
prepared to begin transmitting to the antennas and finally slowly begin
turning on the telescope's many systems and five high-tech instruments.
	``I think we're ready to roll,'' said Moore. ``I think we should be
moving smartly into the activity of getting on with .... starting to
turn things on.''

Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/04/90
Date: 4 May 90 00:15:16 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      HUBBLE SPACE TELESCOPE
                          MAY 4, 1990
 
     Hubble Space Telescope Operators completed dumping the full
contents of all three spacecraft engineering and science tape
recorders yesterday for analysis.  The downlink includes recorded data
on the first safemode entry last week.  Yesterday morning, the Hubble
team prepared to execute an 18-hour series of tests to evaluate a fine
guidance sensor pattern match variance.  The pattern match compares
pinpoints of starlight with predicted data and evaluates pointing
system performance.  An earlier test of the sensors indicated a slight
oscillation of the telescope's roll axis.  The test was hampered by
communication dropouts, but operators hope to complete the pattern match 
test when the data is retrieved during the next tape recorder dump. 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

According to an NPR report last week, the antenna problem was caused by a
'loop' in the cable that attaches to the rotating dish. In a certain
position there is enough slack in the cable to cause a loop to form and the
dish snagged in the loop. The engineers also said that the problem could
not be resolved by a shuttle astronaut because the arm could not support
the stress of someone holding on to it while making the repair.

The arm will be reprogrammed so its movement is limited to avoid the 
position where it can become snagged. This could cause a transmission 
scheduling problem if the dish can only take aim at the communications 
sattelite during a further limited window. The tape device on board the HST 
will hopefully be able to hold enough 'pictures' for a longer stretch 
between transmissions - and download fewer of them (?!) during the shorter 
transmission window. 

I'm looking forward to having one of the HST pictures displayed in my
'pause' window..... :)

Lance

From: [email protected]
Newsgroups: clari.tw.space,clari.news.aviation
Subject: More Hubble trouble
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 3 May 90 23:13:11 GMT
Lines: 62
Approved: [email protected]
Note: (complete writethru -- adding guidance system problem; quotes)


	GREENBELT, Md. (UPI) -- The Hubble Space Telescope's critical
guidance system was tested for the first time Thursday and engineers
unexpectedly discovered signs that the $1.5 billion observatory was
slowly wobbling back and forth.
	Engineers at NASA's Goddard Space Flight Center in Greenbelt and
the Marshall Space Flight Center in Huntsville, Ala., began 18 hours of
tests on the 12-ton telescope's precision pointing system, built to keep
the giant instrument firmly locked onto guide stars during astronomical
observations.
	But ground controllers were surprised to receive data showing the
massive observatory was slowly bobbing back and forth about one 600th of
a degree every minute, far more than allowable.
	``The fine guidance system (FGS) is the instrument that detected
the oscillation,'' said David Pine, deputy program manager of the
telescope project. ``You're looking at a very slow, very slight motion.
	``In the scale of the fine guidance sensor, it's a big number. But
we've just begun working with the FGS and there's going to be a lot of
tweaking and adjustments and analysis that has to get done. We don't
even known whether the FGS is where the oscillation originates.''
	As one scientist put it, ``rather than holding (a guide) star
absolutely steady, it's allowing the star to drift up and down. It's
certainly an oscillation that needs to be gotten rid of.''
	The fine guidance sensor testing ran into trouble earlier due to
communications problems and the unexpected wobble forced engineers to
begin a fresh analysis of data beamed down from on-board tape recorders
to figure out what was causing the unwanted motion.
	As for the potential impact of the latest snag in space telescope
activation, Pine said ``it's premature to get upset.''
	``I would expect we'll solve the problem and probably solve it
fairly quickly. We're just beginning to get the data down to look at it
in detail,'' he said.
	Pine said problems, to some extent, are unavoidable given the
telescope's sheer complexity.
	``It's got a gigantic ground system (that is) attached to the most
complex unmanned satellite we've ever launched,'' he said. ``It's a
combination that's going to take a while to learn. The telescope, to its
credit, is doing everything we're directing it to do.''
	The guidance system testing began after the telescope's hatch was
apparently closed for a second time by accident.
	A ``data uplink error to the telescope's computer'' triggered an
``inertial hold mode'' Wednesday night, causing the door that protects
the telescope's sensitive equipment to close as ``a normal part of
inertial hold,'' a NASA statement said.
	Engineers were pleased that the door closing did not ``upset the
telescope's rate gyros,'' which has just been reprogrammed to be less
sensitive because movement of the door had sent the telescope into
time-consuming hibernation-like states twice before, the statement said.
	The door was reopened at about 11:25 p.m. ``and operators continued
with their planned activities,'' the statement said.
	The pointing system will be critical when the telescope begins its
15-year mission of studying stars, planets and galaxies in the far
reaches of the universe.
	The mission is expected to revolutionize understanding of the
birth, structure and ultimate fate of the universe by peering more
deeply and with greater clarity into the universe than ever before.
	The telescope was placed into orbit last week by the space shuttle
Discovery and technicians began an eight-month process of slowly turning
on the telescope's many systems and five high-tech instruments.
	Problems in the initial steps of slowly starting the telescope
forced NASA  behind schedule in the eight-month process, delaying the
historic first image of the heavens.

Path: shlump.nac.dec.com!e2big.dec.com!decwrl!looking!clarinews
From: [email protected]
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.top
Subject: Hubble Space Telescope's first picture delayed
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 4 May 90 21:51:24 GMT
Lines: 51
Approved: [email protected]


	GREENBELT, Md. (UPI) -- NASA tested the Hubble Space Telescope's
instruments Friday in preparation for taking the observatory's historic
first picture of the heavens, an image delayed until next week by the
balky start-up.
	Engineers at the Goddard Space Flight Center in Greenbelt and the
Marshall Space Flight Center in Huntsville, Ala., sent commands to the
telescope's science computer and received test data in return for the
first time.
	Workers also spent the day beaming another set of commands to the
12-ton telescope as it orbited 381 miles above Earth to test components
of some of the telescope's five high-tech instruments.
	In addition, telescope scientists said they received good results
from the first test of the telescope's system for finding and locking
onto stars that will be used to locate targets during the telescope's
15-year mission.
	After the $1.5 billion telescope was placed into orbit last week by
the crew of the space shuttle Discovery, technicians began an
eight-month process of slowly turning on the complicated observatory's
many systems and instruments.
	The telescope is expected to revolutionize astronomy by studying
stars, planets and galaxies in greater detail than ever before.
	Scientists hoped one of the telescope's cameras would capture a
picture of a star cluster this weekend. The image, called ``first
light,'' is intended as a test. But a series of problems put the
start-up more than a week behind schedule, delaying ``first light''
until early next week at the soonest.
	``This is probably the most complex spacecraft that we've ever
flown,'' said NASA's Mike Harrington, who is helping direct the
start-up.
	``You know you're going to have these kinds of things -- unexpected
and unpredicted little quirks of the spacecraft that you have to take
your time and analyze and figure out. It's kind of frustrating but it's
certainly nothing out of the ordinary or unexpected.''
	NASA astronomer Edward Weiler likened the space telescope's early
activation problems to a 1-year-old stumbling and falling down ``and it
was reported he was crippled.''
	``It's a complex beast,'' he said.
	While earlier problems with the telescope's solar panels and
high-speed communications antennas have been resolved, ground
controllers were studying why the telescope appeared to be rolling
slightly.
	But the rolling motion should have no major impact on research with
the telescope and probably will be corrected, Weiler said.
	``We're not terribly concerned,'' said Weiler. ``One, it's not a
major impact to science, and two, we think we can fix it.''
	The telescope's ability to precisely measure the positions of
stars, called astrometry, could be affected to some degree if it is not
fixed, he said.
	``We would have an impact on astrometry,'' Weiler said. ``But there
are many other ways to control roll.''

    I wonder how much of a hindrance it is to the folks calibrating
    the HST to have this constant barrage of media interest in their
    every move.
    
    It must be like trying to learn to drive a car with a "Candid Camera"
    crew in the back seat.
    
    
    Dave Hazel

From: [email protected]
Newsgroups: clari.tw.space
Subject: Hubble Space Telescope's first picture could come Friday
Keywords: space, science
Message-ID: <[email protected]>
Date: 7 May 90 21:04:25 GMT
Lines: 43
Approved: [email protected]


	GREENBELT, Md. (UPI) -- The Hubble Space Telescope could snap its
historic first picture of the heavens as early as Friday, officials said
Monday.
	Operators at NASA's Goddard Space Flight Center planned to begin a
36-hour process Tuesday in preparation for the first picture.
	The ``bootstrap'' process involves beaming computer commands to the
telescope to practice positioning the 12-ton observatory, locking its
sensors onto stars and focusing the so-called wide field planetary
camera.
	The camera is the instrument that will take the first image since
the crew of the space shuttle Discovery placed the long-awaited
telescope into orbit 381 miles above Earth on April 25.
	``We could (take the first picture) as early as Friday,'' said
NASA's Mike Harrington, adding that officials should have a more
definite idea of when the picture will be taken by the end of the day
Tuesday.
	``It could be as early as Friday (but) it might be Saturday,'' said
Harrington.
	The subject of the picture, which is intended as a test and not to
produce any new discoveries, will be a 3 billion-year-old star cluster
known as NGC 3532, about 1,500 light years from Earth in the
constellation Carina.
	NASA had hoped to take the picture last week, but a series of
problems in the initial stages of turning on the $1.5 billion telescope
put what will be a painstaking eight-month process more than a week
behind schedule.
	Technicians have resolved most of the problems but were studying
unusual  movement in the telescope whenever it goes into or out of
sunlight, Harrington said.
	``It's just a very small disturbance ... that carries on for a few
minutes,'' Harrington said. ``It has something do with entering and
exiting sunlight.''
	Engineers Monday began sending 24 hours of computer commands to the
observatory instructing it to continue finding and locking onto stars to
test the craft's guidance system.
	The telescope is expected to help astronomers gain fundamental new
understanding about how the universe was formed, the age of the cosmos,
how galaxies are structured and perhaps the ultimate fate of the
universe.
	Equipped with five highly advanced instruments and placed above
Earth's obscuring atmosphere, the telescope will enable astronomers to
study planets, stars and galaxies in greater detail than ever before.

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/08/90
Message-ID: <[email protected]>
Date: 8 May 90 20:38:34 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 19


                  Hubble Space Telescope Update
                         May 8, 1990
 
     As the HST begins its third week in orbit, operators
from the Space Telescope Operations Control Center at Goddard are
continuing the process to activate and "tune" the telescope before
handing it over to the Space Telescope Science Institute in
Baltimore, MD.  At this time the telescope systems are healthy, in
proper working order, with only occasional, minor anomalies to
report.  A fine guidance sensor star pattern match test was
unsuccessful yesterday morning due to the scarcity of higher
magnitude stars in the sensors' fields of view.  Operators are not
overly concerned since other pattern matches have been successful.

 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

    	Latest word from the grapevine says that the "first light" image to
    be taken by hst will be postponed until "late next week" due to the
    guidance sensor problems recently experienced.
    
    				Drew
    

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/09/90 (Forwarded)
Message-ID: <[email protected]>
Date: 9 May 90 16:37:32 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 52
Xref: shlump.nac.dec.com sci.space:19263 sci.astro:7291

UNITED PRESS INTERNATIONAL -- MAY 9
 
"Hubble Space Telescope's First Picture Could Come Wednesday"
 
"The Hubble Space Telescope could take its first picture of the
cosmos as early as Wednesday, a NASA official said."
 
UPI states that NASA engineers are considering snapping a picture
of a star cluster in the Milky Way to help orient the giant
observatory.  Quoting from orbital verification manager Mike
Harrington, UPI says the picture, previously scheduled to be
taken no earlier than Friday, could be moved up to help assist in
the resolution of a guidance system problem which came up in
tests performed the past few days.
 
UPI states that NASA has resolved most of the problems which have
affected the Hubble Telescope check-out tests so far but that two
unusual problems involving spacecraft motion were still being
tracked.
 
                      * * * * * * * *
 
ASSOCIATED PRESS -- MAY 9
 
By Harry Rosenthal
 
"NASA engineers hope to snap the first photograph with the Hubble
Space Telescope's main camera today despite a new setback in
getting the instrument started on its 15-year star-gazing
mission."
 
AP says the picture would be made late today if engineers decide
to interrupt the telescope's shakedown process, now in its third
week.
 
Rosenthal says the picture would be of a 3-billion-year-old star
field called Theta Carina, or "Ship's Keel," located in the
southern sky and that the star cluster is 1,260 light years away
and visible with the naked eye in Africa, South America and
Australia.
 
AP concludes by saying NASA is about a week behind schedule in
the check-out process and that engineers are concentrating their
efforts on resolving two problems associated with spacecraft
motion, one a jittery motion when the telescope is commanded to
roll, and the other a shaking motion when the telescope passes
from shadow into sunlight during its orbit.

 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers

  I found out something about the HST door from reading some back issues of
AWST. The author of the article said that the HST door is only suppose to close
in an emergency situation, particularly if the computer program decides that
the telescope is about to point toward the sun. 

  The door closed by accident the other day when they were testing the part of
software that handles emergencies related to the door. They were suppose to set
a switch that would prevent the door from closing during the test but they
didn't. When the test data indicated that the HST was going to point toward the
sun, the "safe mode" software closed the door.

  They were able to open it again without incident a few hours later. If the
door had gotten jamed shut, they would have had to wait until 1991 or 1992
(that's NASA for 1993) to send a shuttle up with a crew to open it by hand.

  George

Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/09/90
Date: 9 May 90 20:50:02 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
                                                         
 
                     HUBBLE SPACE TELESCOPE UPDATE
                            MAY 9, 1990
 
Activation and checkout of the Hubble Space Telescope's
science instruments is continuing to progress well.  The
Faint Object Camera is reported to be ready to have its high
voltage switched on.  The High Speed Photometer has had all five
of its detectors activated at low voltage.  The Goddard High
Resolution Spectrograph low voltage checkout is continuing and
monitoring continues of the Faint Object Spectrograph aft shroud
pressures.
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/10/90 (Forwarded)
Date: 10 May 90 16:32:52 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
THE NEW YORK TIMES -- MAY 10
 
"Old Error Stalls Focusing of Space Telescope"
 
By John Noble Wilford
 
"An error made years ago in planning has set back efforts to
focus the Hubble Space Telescope and delayed by at least another
week an attempt to take the first picture of the heavens with the
$1.5 billion instrument."
 
Revised commands radioed to the telescope tonight could result in
the first picture being snapped Wednesday according to the
Times.  If a second test becomes necessary, the picture may be
delayed another two days.
 
Wilford says engineers found that a pointing error of half a
degree caused by use of an outdated star chart had been
programmed into the telescope computer.
 
The Times report states that the first picture should magnify
objects about as well as fairly large Earth-based telescopes
while later pictures will be able to see objects out close to the
edge of the universe seven times clearer than the largest ground
telescopes.
 
The first test photo subject is a 3-billion year-old star field,
Theta Carina, the "Ship's Keel", some 1,260 light years away.
 
                      * * * * * * * *
 
WASHINGTON TIMES -- MAY 10
 
"Math Mistake Points Hubble Wrong Way"
 
"A simple math mistake -- somebody added when he should have
subtracted, or vice versa -- caused the Hubble Space Telescope to
miss its target stars and point to the wrong spot in the heavens,
embarrassed scientists said yesterday."
 
The Times quotes Hubble deputy manager Jean Olivier saying, "when
we were trying to point the telescope to the center of a pretty
rich star field with a high probability of acquisition, we were
really off to one side of that."
 
The story says because of this error, the first picture from the
telescope won't be taken until sometime next week.
 
                      * * * * * * * *
 
WASHINGTON POST -- MAY 10
 
"First Space Pictures From Jittery
Hubble Telescope Still Several Days Away"
 
By Kathy Sawyer
 
"After two weeks in orbit, the Hubble Space Telescope has not
shaken its opening-night jitters and is not expected to return
its 'first light' images to Earth until at least next Wednesday,
its handlers said yesterday."
 
The Post story cites Hubble oscillation and jitter problems and
describes the math error committed by Space Telescope Science
Institute staff in correcting a 1954 sky chart for use by the
telescope fine guidance system.
 
Sawyer then quotes from the STS-31 post-flight crew press
conference and mission specialist Bruce McCandless, "this is not
your garden variety satellite.  What you're seeing now are the
first efforts in working our way through the things which are
zero-gravity and orbit related" and couldn't be tested before
launch.  Sawyer cites the astronauts' plea that the public and
media maintain patience while the telescope team tackles start-up
problems.
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/10/90
Date: 10 May 90 22:07:37 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                     HUBBLE SPACE TELESCOPE UPDATE
                              MAY 10, 1990
 
    With the completion of the low voltage and flight functional
testing of Goddard High Resolution Spectrograph (GHRS), all of the
science instruments aboard the Hubble Space Telescope have now
essentially completed their low voltage and flight functional testing.
The next step in verifying the science instruments will be to test
the instruments' high voltage operations. 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

Subject: Hubble Space Telescope Update - 05/11/90
Date: 11 May 90 22:57:45 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                  Hubble Space Telescope Update
                          MAY 11, 1990
 
     Engineers continue to test the systems on the Hubble Space
Telescope in preparation for the first picture.  Thursday night, at 6
p.m. EDT, operators at the Space Telescope Operations Control Center
initiated an analytical test of the Hubble Space Telescope's pointing
and control system and fine guidance sensors. First indications from
the test which concluded at 6 a.m. Friday morning, are that the fine
guidance sensors are working properly, and were able to lock on to and
track designated guide stars in what is called the "course track
mode."  Data from the test is now being analyzed. 

       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.gov.agency,clari.news.aviation,clari.tw.science
Subject: Hubble Space Telescope guidance system tested
Keywords: space, science, government agencies, government, air transport,
Message-ID: <[email protected]>
Date: 11 May 90 21:42:03 GMT
Lines: 58
Approved: [email protected]

	WASHINGTON (UPI) -- NASA engineers tested the Hubble Space
Telescope's guidance system Friday in the hopes of taking the $1.5
billion orbiting observatory's historic first picture next week.
	While still struggling to solve two abnormal movements in the
12-ton telescope, technicians at the Goddard Space Flight Center in
Greenbelt, Md., began a 36-hour process of testing the telescope's three
fine guidance sensors.
	Workers earlier had completed a 12-hour process of testing the
system's ability to find and lock on to particular stars, successfully
doing so in three out of five tries as the telescope orbits 381 miles
above Earth.
	``We learned a lot of things we should do. We also learned some
things we shouldn't do,'' said NASA's Mike Harrington, who is helping
direct the telescope's start-up.
	The pointing system will be critical during the 15-year mission of
the telescope, which is expected to revolutionize astronomy by studying
stars, planets and galaxies in greater detail than ever before.
	The testing began after correcting a math error that occurred while
updating a 1954 star chart. The error, which pointed the telescope in
the wrong direction, spoiled an earlier guidance system test and delayed
the first picture.
	After completing the guidance tests, engineers will begin a 38-hour
process of focusing the telescope's wide field planetary camera, which
will take the telescope's historic ``first light'' picture between May
16 and May 18 depending on whether the process needs repeating.
	The subject of the picture, which is intended as a test and not to
produce any new discoveries, will be a 3 billion-year-old star cluster
known as NGC 3532, about 1,500 light-years from Earth in the
constellation Carina. A light-year, the distance light travels in one
year, is about 5.8 trillion miles.
	NASA had hoped to take the picture earlier but problems in the
start-up process that began after the telescope was deployed by the crew
of the space shuttle Discovery April 25 put the work behind schedule.
	Technicians resolved most of the problems but were still working on
two unusual movements in the telescope, one of which had been slightly
improved, said Jean Olivier, deputy project manager for the telescope.
	``It was significantly reduced but it's still not a space telescope
performance we're looking for,'' he said.
	Analysts were studying data from the telescope and running computer
simulations that should ``hopefully come up with another fix'' to
eliminate the slight instability, he said.
	``With the data that we have and the amount of expertise we have
... we just feel it's not an insurmountable problem, although it's
elusive at this time,'' he said.
	The telescope also vibrates for about five minutes when it goes
from sunlight into dark and up to 30 minutes when it goes from dark back
into the sun, probably because of some glitch associated with the solar
panels, he said.
	``We're all but certain it's the solar arrays that's exciting the
spacecraft.  We haven't determined what's exciting the solar arrays,''
he said.
	NASA scientist Edward Weiler said he was confident the problems
would be fixed and stressed they would not affect the early operation of
the craft, including the ability to take the first photograph.
	``I'm getting more and more excited because I'm believing more and
more that it's going to happen,'' he said. ``The excitment is building
up in a lot of us.''

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/14/90 (Forwarded)
Message-ID: <[email protected]>
Date: 14 May 90 15:47:48 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 41

ASSOCIATED PRESS -- MAY 12
 
"The Hubble Space Telescope sees about 15 sunrises and sunsets
every day, and it wobbles each time.  Scientists are puzzled."
 
AP says NASA telescope officials are trying to figure out why the
telescope wobbles  for 10 to 30 minutes after it emerges from the
Earth's shadow on each orbit.  The wire story says engineers are
considering whether the problem is related to a slight twist
noticed in one of the solar panels by the STS-31 crew when the
telescope was deployed.
 
                      * * * * * * * *
 
UNITED PRESS INTERNATIONAL -- MAY 12
 
"Hubble Space Telescope Focusing Set"
By Rob Stein
 
"NASA engineers began focusing the Hubble Space Telescope
Saturday in preparation for taking the $1.5 billion orbiting
observatory's historic first picture of the heavens this week."
 
UPI says that if all goes well, the telescope's Wide
Field/Planetary Camera will snap the "first light" picture
between Wednesday and Friday (this week) depending on how much of
a 38-hour focusing task needs to be repeated.
 
The wire says engineers also completed an important set of tests
on the spacecraft's guidance system, tested several of the
instruments and turned on high power to one of them.
 
Stein says most of the problems encountered have been resolved
except for two -- each pertaining to unusual spacecraft motion.
UPI then quotes from program scientist Dr. Edward Weiler, who is
confident all of the problems would be fixed.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.top
Subject: Hubble Space Telescope focusing set
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 13 May 90 02:59:17 GMT
Lines: 38

	WASHINGTON (UPI) -- NASA engineers began focusing the Hubble Space
Telescope Saturday in preparation for taking the $1.5 billion orbiting
observatory's historic first picture of the heavens this week.
	As the 12-ton telescope orbited 381 miles above Earth, technicians
at the Goddard Space Flight Center in Greenbelt, Md., and Marshall Space
Flight Center in Huntsville, Ala., began the work of commencing a
38-hour ``bootstrap'' process of focusing the craft's mirrors.
	If all goes well, the telescope's wide field planetary camera will
snap the telescope's historic ``first light'' picture between Wednesday
and Friday depending on whether the process needs repeating.
	The subject of the picture, which is intended as a test and not to
produce any new discoveries, will be a 3 billion-year-old star cluster
known as NGC 3532, about 1,500 light-years from Earth in the
constellation Carina. A light-year, the distance light travels in one
year, is about 5.8 trillion miles.
	Workers Saturday also completed an important set of tests on the
telescope's guidance system, tested several instruments and turned on
full power to the high-speed photometer -- a high-tech light meter -- and
faint object camera.
	The guidance system and instruments will be critical during the
15-year mission of the telescope, which is expected to revolutionize
astronomy by studying stars, planets and galaxies in greater detail than
ever before.
	NASA had hoped to take the telescope's first picture about a week
after it was deployed by the crew of the space shuttle Discovery on
April 25, but problems in the painstaking start-up process put the work
behind schedule.
	Technicians resolved most of the glitches -- including the most
recent one involving the guidance system that resulted from a simple
math error -- but were still working on two unusual movements in the
telescope.
	NASA scientist Edward Weiler said he was confident the problems
would be fixed and stressed they would not affect the early operation of
the craft, including the ability to take the first photograph.
	``I'm getting more and more excited because I'm believing more and
more that it's going to happen,'' he said. ``The excitment is building
up in a lot of us.''


================================================================================
From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.gov.usa
Subject: Hubble Space Telescope fails to find stars
Keywords: space, science, air transport, transportation, usa federal,
Message-ID: <[email protected]>
Date: 14 May 90 15:21:28 GMT
Lines: 40

	WASHINGTON (UPI) -- The Hubble Space Telescope failed to lock onto
stars during an initial attempt to focus its mirrors, possibly delaying
the observatory's first picture until the end of the week, an official
said Monday.
	NASA engineers were unable to locate and lock onto stars in five
attempts with the 12-ton telescope during a 38-hour focusing process
that began Saturday, said spokesman John Dumoulin of the Marshall Space
Flight Center in Huntsville, Ala.
	``They didn't get a lock in any of the attempts,'' said Dumoulin.
``There are a lot of theories why.''
	The failure means ground controllers will probably repeat the
process, he said. Last week officials said they hoped to take the
telescope's first picture between Wednesday and Friday, depending on
whether the process needed repeating.
	Technicians have sent a series of new commands to the telescope as
it orbits 381 miles above Earth in the hopes of correcting slight
misalignments that may have caused the snag, Dumoulin said.
	``They uplinked some commands to change the attitude slightly and
desensitized the gyros. The gyros were switching from high to low mode
when the telescope went from night to day, which was causing slight
attitute shifts,'' he said.
	``All this is part of the teething of the telescope as we fine tune
it,'' said Dumoulin.
	The crew of the space shuttle Discovery placed the telescope into
orbit April 25. The $1.5 billion telescope is expected to revolutionize
astronomy by studying stars, galaxies and planets in greater detail then
ever before during its 15-year mission.
	Officials had hoped to snap the telescope's first picture about a
week after the telescope was deployed. But the picture has been delayed
by a series of glitches as engineers began an eight-month process of
slowly turning on the complicated telescope.
	Most of the problems have been resolved but workers are still
trying to correct two unusual movements in the telescope, including one
that occurs whenever the craft goes in and out of sunlight.
	The subject of the picture will be a 3 billion-year-old star
cluster known as NGC 3532, which is located about 1,500 light years from
Earth in the constellation Carina. A light year is about 5.8 trillion
miles. The picture is intended as a test and not to produce any new
discoveries.

===============================================================================

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation
Subject: Hubble Space Telescope picture delayed again
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 14 May 90 22:13:31 GMT
Lines: 66

	WASHINGTON (UPI) -- The Hubble Space Telescope, distracted by an
unexpectedly bright ``rogue star,'' failed to complete its first
focusing test, again delaying the observatory's historic first picture,
officials said Monday.
	The $1.5 billion telescope, which officials had hoped would snap
its long-awaited first image of the heavens between Wednesday and
Friday, will not take the picture until Saturday at the earliest,
officials said.
	Even so, NASA astronomer Edward Weiler said the telescope's myriad
electronic systems were operating properly and that other aspects of the
instrument's activation were running ahead of schedule.
	``We feel badly that it's taken this long, but ... this is a
complex machine,'' he said. ``When an Indy 500 racer rolls off the
assembly line you don't drive it around the course at 230 mph. You're
constantly trying to tune it up. We're going to be tuning this thing up
for a long time.''
	The latest problem cropped up over the weekend when despite five
attempts, the telescope was unable to locate and lock onto specific
``guide stars'' needed to pinpoint its position for a 36-hour focusing
process that began at 6 p.m. Saturday, officials said.
	NASA engineers believe the problem was caused by a star in the area
the telescope was viewing that turned out to be brighter than
anticipated, causing the telescope to mistakenly point towards it and
preventing the instrument from locking onto the proper stars for correct
guidance.
	``The problem was analyzed overnight. The star was discovered in
the catalogue, it was discovered as a suspect star, or a rogue star,''
said Weiler.
	After the problem was discovered, workers at the Goddard Space
Flight Center in Greenbelt, Md., and Marshall Space Flight Center in
Huntsville, Ala., instructed the telescope to ignore the star so the
focusing procedure could be repeated successfully, beginning at 8 p.m.
Monday.
	The focusing process will probably have to be completed twice
successfully, and another set of tests on the guidance system will have
to be done, before the telescope takes its first picture with its wide
field planetary camera.
	The subject of the picture will be a 3 billion-year-old star
cluster known as NGC 3532, which is located about 1,500 light years from
Earth in the constellation Carina. A light year is about 5.8 trillion
miles. The picture is intended as a test and not to produce any new
discoveries.
	While disappointed by the latest delay, officials said work was
ahead of schedule in other areas and they were not discouraged by the
overall pace of the telescope's painstaking start-up.
	``I think everybody's got a lot of confidence that given some time,
we're going to get this thing to meet (specifications),'' Weiler said.
``It's just taking a little longer.''
	Placed into orbit 381 miles above Earth on April 25 by the crew of
the space shuttle Discovery, the telescope is supposed to revolutionize
astronomy by studying stars, galaxies and planets in greater detail then
ever before during its 15-year mission.
	Officials had hoped to take the telescope's first picture about a
week after deployment. But work has been delayed by a series of glitches
as engineers began an eight-month process of slowly turning on the
complicated telescope.
	Most of the problems have been resolved but workers are still
trying to correct two unusual movements in the telescope, including a
jitter that occurs whenever the craft goes in and out of sunlight.
	In the meantime, engineers have turned on full power to the
telescope's faint object camera and tested the telescope's four other
high-tech instruments.
	``We seem to be really hitting on all cylinders in everything
except the pointing-stability area,'' said Jean Olivier, deputy project
manager.

Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/15/90
Date: 15 May 90 19:57:43 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                   Hubble Space Telescope Update
                         May 15, 1990
 
    At 8 p.m. (EDT) tonight, operators at the Space Telescope
Operations Control Center will begin a 38-hour repeat of previously
used but updated "Bootstrap Phase A" focusing commands, called
"loads". The telescope has achieved five good locks onto guide stars
and five successful attitude updates.  All the telescope's flight
systems are functioning well and checkout and activation of the
science instruments is ahead of schedule. After one successful
Bootstrap Phase A sequence, engineers will perform a pattern matching
test between predicted star patterns and points of light actually
observed by the telescope's fine guidance sensors.  They will then
repeat Bootstrap Phase A on Friday to further refine focusing of the
secondary mirror.  "First light", the first image taken by a science
instrument, could occur by week's end. 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/15/90
Message-ID: <[email protected]>
Date: 15 May 90 19:57:43 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 22

                   Hubble Space Telescope Update
                         May 15, 1990
 
At 8 p.m. (EDT) tonight, operators at the Space Telescope Operations
Control Center will begin a 38-hour repeat of previously used
but updated "Bootstrap Phase A" focusing commands, called "loads".
The telescope has achieved five good locks onto guide
stars and five successful attitude updates.  All the telescope's
flight systems are functioning well and checkout and activation of
the science instruments is ahead of schedule. After one successful
Bootstrap Phase A sequence, engineers will perform a pattern
matching test between predicted star patterns and points of light
actually observed by the telescope's fine guidance sensors.  They
will then repeat Bootstrap Phase A on Friday to further refine
focusing of the secondary mirror.  "First light", the first image
taken by a science instrument, could occur by week's end.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/16/90 (Forwarded)
Message-ID: <[email protected]>
Date: 16 May 90 16:07:11 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 77

NEW YORK TIMES -- MAY 16
 
"Hubble Telescope Able To Focus"
By John Noble Wilford
 
"After three troubled weeks trying to steady a wiggling
spacecraft and fix its sights on the heavens, ground controllers
said yesterday that the Hubble Space Telescope was responding
reliably to commands and was for the first time focusing on guide
stars."
 
The Times says this latest activity clears the way for the
telescope's first picture on Sunday.  The story also reports NASA
officials are encouraged by this and quotes telescope test chief
Mike Harrington saying "it was a very satisfying day."
 
The Times also reports that other spacecraft tests including
those on the five instruments have been successful.
 
In conclusion, the paper quotes from telescope chief scientist
Dr. Ed Weiler, saying "for the first time we now are sure we know
where we are pointing and how to lock on to stars and maintain
our position.  It's a significant accomplishment."
 
                      * * * * * * * *
 
USA TODAY -- MAY 16
 
"Hubble Sets Up for Photo Show Sunday"
 
"The Hubble space telescope is pleasing its NASA handlers at
last."
 
USA Today says jubilant managers reported the telescope was able
to lock onto the correct set of guidance stars and quotes deputy
project manager Jean Olivier as saying "we've got high hopes
now."
 
The paper also quotes telescope scientist Dr. Weiler saying "as
an astronomer, it's the most exciting day since the launch."
 
USA Today, cautions that the telescope's troubles aren't over
just yet, though, citing the wobble which occurs each time the
telescope emerges from the Earth's shadow into sunlight.
 
                      * * * * * * * *
 
UNITED PRESS INTERNATIONAL -- MAY 16
 
"Hubble Space Telescope Mirrors Focused"
By Rob Stein
 
"Jubilant NASA scientists began focusing the Hubble Space
Telescope like a pair of giant binoculars and predicted the
orbital observatory could take its historic first picture of the
heavens Sunday."
 
The UPI reports that engineers sent commands Tuesday that moved
one of the two near-perfect mirrors about 240-thousandths of an
inch in the first steps of painstakingly focusing the telescope's
optical system.
 
The wire reports the work was part of a 36-hour process involving
the focusing of the secondary mirror which will be followed by a
38-hour guidance system test and then another 36-hour focusing
process.
 
UPI states that if all goes well, the first picture, of a three-
billion-year-old star cluster located about 1,500 light years
from Earth, could be taken Sunday afternoon but cautions the
picture is actually part of a test and not expected to produce
new discoveries.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation
Subject: Hubble Space Telescope mirrors focused
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 15 May 90 22:16:50 GMT
Lines: 56

	WASHINGTON (UPI) -- Jubiliant NASA scientists began focusing the
Hubble Space Telescope like a pair of giant binoculars Tuesday and
predicted the orbital observatory could take its historic first picture
of the heavens Sunday.
	As the 12-ton telescope orbited 381 miles above Earth, engineers
sent commands that moved one of two near-perfect mirrors about 240
thousandths of an inch in the first steps of painstakingly focusing its
optical system.
	The critical milestone followed successful efforts overnight to
finally get the $1.5 billion telescope's high-precision fine guidance
sensors to lock onto selected stars to keep the instrument pointed in
the right direction.
	``From my perspective as an astronomer, it's an especially exciting
day. Since the launch, this has been the most exciting day,'' said
project scientist Edward Weiler.
	``For the first time, we now are sure we know where we're pointing.
We can point to a place in space and actually find the stars that are
supposed to be there, lock up on them and measure them and use them for
focusing. So it's a significant accomplishment,'' he said.
	The work was part of a 36-hour ``bootstrap'' focusing process that
began at 8 p.m. Monday and will be followed after 8 a.m. Wednesday by a
38-hour guidance system test and another 36-hour focusing procedure.
	If all goes well, the work will lead sometime Sunday -- probably
Sunday afternoon -- to the telescope's wide field planetary camera
snapping the observatory's first picture, Weiler said.
	The focusing process involves locating and locking onto stars and
moving the telescope's 12-inch, 27-pound secondary mirror, which is 16
feet from a 94.5-inch, 1,827-pound primary mirror. The secondary mirror
can move only a total of little more than one-tenth of an inch.
	``It's like the focusing mechanism on your binoculars,'' Weiler
said. ``What you do usually is you focus it to where you think the focus
is and go a little farther and then you come back and then you do
several iterations until you get it in perfect focus. That's exactly the
process we're using here, too.''
	Light enters the telescope, bounces off the primary mirror back up
to the secondary mirror mounted near the opening and back down through a
hole in the primary mirror to a point where cameras and other
instruments can record the concentrated light.
	The subject of the first picture will be a 3 billion-year-old star
cluster known as NGC 3532, located about 1,500 light years from Earth in
the constellation Carina. A light year is about 5.8 trillion miles. The
picture is intended as a test and not to produce any new discoveries.
	The telescope failed a weekend focusing test when an unexpectedly
bright ``rogue star'' pulled the telescope out of position, dashing
hopes of snapping the first picture between Wednesday and Friday.
	Ferried into space by the shuttle Discovery, the telescope is
expected to revolutionize astronomy by studying stars, galaxies and
planets in greater detail then ever before during its 15-year mission.
	Officials initially hoped to take the first picture about a week
after deployment. But the step was delayed by a series of glitches as
engineers began an eight-month process of slowly turning on the
complicated telescope.
	While most of the problems have been resolved, workers are still
trying to correct two unusual movements in the telescope, including a
vibration that occurs whenever the craft goes in and out of sunlight.

================================================================================
From: [email protected]
Newsgroups: clari.tw.space,clari.news.aviation
Subject: Hubble Space Telescope adjusting continues
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 17 May 90 01:01:56 GMT
Lines: 30
Codes: ynssdxx., ybtadxx.

	WASHINGTON (UPI) -- NASA engineers completed the first stage of
focusing the Hubble Space Telescope Wednesday and began a guidance
system test necessary before the observatory can take its first picture,
possibly on Sunday.
	Technicians at the Goddard Space Flight Center in Greenbelt, Md.,
began a 38-hour process at 8 a.m. of testing the craft's three fine
guidance sensors, which are needed to position the 12-ton, $1.5 billion
telescope.
	The process began after a 36-hour focusing procedure that brought
the telescope within .0000747 of an inch of being focused, officials
said.
	The guidance tests will be followed at 10 p.m. Thursday by a second
36-hour focusing procedure that will enable the telescope's wide field
planetary camera to take the telescope's first picture Sunday if all
goes well.
	The subject of the picture will be a 3 billion-year-old star
cluster known as NGC 3532, located about 1,500 light years from Earth in
the constellation Carina. A light year is about 5.8 trillion miles. The
picture is intended as a test and not to produce any new discoveries.
	Ferried into space by the shuttle Discovery, the telescope is
expected to revolutionize astronomy by studying stars, galaxies and
planets in greater detail then ever before during its 15-year mission.
	Officials initially hoped to take the first picture about a week
after deployment. But the step was delayed by a series of glitches as
engineers began an eight-month process of slowly turning on the
complicated telescope.
	While most of the problems have been resolved, workers are still
trying to correct two unusual movements in the telescope, including a
vibration that occurs whenever the craft goes in and out of sunlight.

A couple of nights ago "Late Night with David Letterman" tossed a few zingers
at the HST.  In his monologue Dave said (paraphrased from memory):
"Did you hear about the trouble with the Hubble Space Telescope.  This is the
 device that will let us look back billions of years into the past to the
 beginning of the universe - and they can't get it focused.  Gee, for 1.5
 billion dollars you'd think we would have bought the autofocus model!"


Later on in the show, the HST made the Top Ten List:

                        Top Ten Reasons for the 
                       Hubble Telescope Problems

  10) THE GUY AT SEARS PROMISED IT WOULD WORK FINE.

   9) SOME KIDS ON EARTH MUST BE FOOLING AROUND WITH A GARAGE DOOR OPENER.

   8) THERE'S A LITTLE DOOHICKEY RUBBING AGAINST THE PART THAT LOOKS KIND
      OF LIKE A COWBOY HAT.

   7) SEE IF YOU CAN THINK STRAIGHT AFTER TWELVE DAYS OF DRINKING TANG.

   6) BUM WITH SQUEEGEE SMEARED LENS AT RED LIGHT.

   5) BLUE PRINT DRAWN UP BY THAT "HEY VERN!" GUY.

   4) THOSE DAMN RACCOONS!

   3) SHOULDN'T HAVE USED G.E. COMPONENTS.

   2) RAN OUT OF QUARTERS.

and.. the number 1 reason for the Hubble Space Telescope problems (drum roll)

   1) RACE OF SUPER-EVOLVED GALACTIC BEINGS ARE SCREWING WITH US.

Is it fair to assume that everything the HST will look at is essentially at
infinity, and that the focussing being done is really just adjusting the optics
to be "exactly" infinity?  I.e. there should be no focussing done as a matter of
course during HST's use?

How do they focus without taking a picture?  (Why does "first picture" always
have the adjective "historic" prepended?)

Burns

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/16/90
Message-ID: <[email protected]>
Date: 16 May 90 23:18:42 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 17

                Hubble Space Telescope Update
                        MAY 16, 1990
 
All the telescope's flight systems are functioning
well and checkout and activation of the science instruments is
ahead of schedule.  Operators continued voltage checks on the
Goddard High Resolution Spectrograph and continued stability and
photometric performance tests on the faint object camera.
Operators plan to repeat Bootstrap Phase A on Friday to further
refine focusing of the secondary mirror.  "First light", the first
image taken by a science instrument, could occur this weekend.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

    The following article gives a little more insight into the focusing
    process and the pointing error problem.  Copied without permision from
    Aviation Week & Space Technology, May 14, 1990.
    
    Mike Hughes
    
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
    
                     FIRST HUBBLE IMAGES DELAYED TO
                 ALLOW CONTROLLERS TO CONDUCT FOCUSING TESTS
    
    The first test pictures from the Hubble Space Telescope were delayed
    until at least this week to enable ground controllers to conduct
    at least one and possibly two optical system focusing exercises
    with the complex observatory.
    
    During the focusing tests the telescope's fine guidence sensors will
    be used to scan the size of the starlight image being reflected
    from the secondary mirror at the forward end of the optical telescope
    assembly back down the barrel of the observatory to its focal plane.
    
    Hubble ground controllers at the Goddard Space Flight Center earlier
    believed the first image wuld be made with the observatory's wide-field
    planetary camera (WF/PC) last week (AW & ST May 7, p32).
    
    That picture was to act as a diagnostic tool to help engineers assess
    why the telescope's fine guidance sensors were not locking onto
    guide stars properly.  The fine guidance sensor "pattern match"
    tests were being done so Hubble could determine precisely where
    it was in relation to guide stars, to use as a basis for maneuvering
    to other attitudes for observations.
    
    The need for the early WF/PC image was negated, however, when engineers
    realized that pointing data provided to the telescope by the Space
    Telescope Science Institute was in error.
    
    The error occurred because someone several years ago inserted a
    plus sign instead of a minus sign in a computer program being prepared
    to aid in early telescope checkout.
    
    The star data being used came from a 1954 star survey.  Engineers
    realized the Earth's precession in relation to the 30-year-old star
    data would have to be accounted for in the Hubble checkout data.
    
    The precession equated to an 18 arc min. reduction in the coordinates
    of the star field, but a programmer accidentally added 18 arc min.
    instead.
    
    That resulted in the telescope being a full 0.5 deg off target in
    the initial pattern recognition tests.
    
    Engineers are still working to solve a 0.1 to 0.14-Hz jitter problem
    the spacecraft exhibits for 20-30 min. every time it passes from
    the dark side of its orbit into sunlight.
    
    The problem appears to be related to thermal effects on the
    spacecraft's twin 40-ft solar array wings.  Engineers doubt the
    jitter will seriously affect the mission.

    Just heard this morning on NPR while driving in to work.
    
    The 'first light' picture was either over exposed or under exposed,
    don't remember exactaly which, but the second picture was better than
    expected, in fact, already 2X better than best ground based picture.
    
    Tony

    I heard that the "first light" picture also showed an unknown binary
    star as well...Les
    

Path: shlump.nac.dec.com!e2big.dec.com!decwrl!looking!clarinews
From: [email protected]
Newsgroups: clari.tw.space,clari.news.gov.agency,clari.tw.science
Subject: Hubble Space Telescope adjusting continues
Keywords: space, science, government agencies, government, research
Message-ID: <[email protected]>
Date: 17 May 90 22:22:59 GMT
Lines: 26

	WASHINGTON (UPI) -- NASA engineers tested the Hubble Space
Telescope's guidance system Thursday and planned a second focusing
procedure in preparation for taking the observatory's first picture of
the heavens, possibly on Sunday.
	``We've had a relatively quiet day in the life of space
telescope,'' said NASA's Mike Harrington, who is helping direct the
telescope's start-up.
	Technicians at the Goddard Space Flight Center in Greenbelt, Md.,
completed a 38-hour process of testing the craft's three fine guidance
sensors, which are needed to position the 12-ton, $1.5 billion
telescope.
	The process began after a 36-hour focusing procedure and was to be
followed late Thursday by a second 36-hour focusing procedure that will
enable the telescope's wide field planetary camera to take the
telescope's first picture Sunday if all goes well.
	``We're still on track,'' said NASA astronomer Edward Weiler. ``I'm
cautiously optimistic.''
	The subject of the picture will be a 3 billion-year-old star
cluster known as NGC 3532, located about 1,500 light years from Earth in
the constellation Carina. A light year is about 5.8 trillion miles.
	The first picture is intended as a test and is not expected to
yield any discoveries.
	Ferried into space by the shuttle Discovery, the telescope is
expected to revolutionize astronomy by studying stars, galaxies and
planets in greater detail then ever before during its 15-year mission.

From: [email protected]
Newsgroups: clari.tw.space,clari.news.gov.agency,clari.tw.science
Subject: Hubble Space Telescope focusing continues
Keywords: space, science, government agencies, government, research
Message-ID: <[email protected]>
Date: 18 May 90 19:11:44 GMT
Lines: 35

	WASHINGTON (UPI) -- NASA engineers focused the Hubble Space
Telescope Friday in preparation for taking the observatory's first
picture, possibly as soon as Sunday.
	As the telescope orbited 381 miles above Earth, engineers at the
Goddard Space Flight Center in Greenbelt, Md., proceeded with a 36
1/2-hour process that began at 10 p.m. Thursday of locating and locking
onto stars to focus the telescope's mirrors.
	``During the data takes, the telescope did not maintain locks onto
its guide stars; operators are awaiting data to determine exactly why
the guide stars were not acquired,'' a NASA statement said.
	``However, the objective of the test, the acquisition of target
stars, was highly successful,'' it said.
	Engineers also completed other routine tests on the 12-ton, $1.5
billion telescope, including power checks on one instrument called the
Goddard High Resolution Spectrograph, the statement said.
	If all goes well, the telescope's wide field planetary camera could
take the telescope's first picture Sunday, probably in the afternoon,
officials said.
	The subject of the picture will be a 3 billion-year-old star
cluster known as NGC 3532, located about 1,500 light years from Earth in
the constellation Carina. A light year is about 5.8 trillion miles.
	The first picture is intended as a test and is not expected to
yield any discoveries.
	Ferried into space by the shuttle Discovery, the telescope is
expected to revolutionize astronomy by studying stars, galaxies and
planets in greater detail then ever before during its 15-year mission.
	Officials had hoped to take the first picture about a week after
the telescope was deployed April 25. But a series of problems put the
careful work of turning on and adjusting the telescope about 10 days
behind schedule.
	Most of the glitches have been solved, but analysts are still
trying to fix three problems, including a vibration that occurs whenever
the telescope goes into or out of sunlight. The calibration will take
eight months to complete.

================================================================================
From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.top
Subject: Hubble Space Telescope first picture set
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 19 May 90 16:24:14 GMT
Lines: 53

	WASHINGTON (UPI) -- The Hubble Space Telescope will snap its
historic first picture of the heavens Sunday, an important step toward
launching the observatory's long-awaited probe of the universe,
officials said Saturday.
	The telescope's wide field planetary camera is expected to take a
one-second exposure of a star cluster Sunday afternoon after engineers
complete last-minute tests on the 12-ton observatory's guidance system.
	Jim Elliott of the Goddard Space Flight Center in Greenbelt, Md.,
said the first images from the telescope will be received at about 1:49
p.m. EDT and processed images would be received at about 2:35.
	The subject of the ``first light'' picture will be the 3
billion-year-old star cluster known as NGC 3532, located about 1,500
light years from Earth in the constellation Carina. A light year is
about 5.8 trillion miles.
	``We're all kind of excited,'' NASA astronomer Edward Weiler said.
``We're all looking forward to getting first light out of the way.''
	The black-and-white picture, which officials had initially hoped to
take about a week after the telescope was placed into orbit 381 miles
above Earth April 25, is intended as a test and not to produce any new
discoveries.
	``To the public it's become a historical event. We look at it as an
engineering test,'' Weiler said. ``We will probably learn nothing of any
scientific value. None of us expect anything of scientific value.''
	Because the $1.5 billion telescope has not been completely
adjusted, the image's quality is expected to be only about equal to that
of an equivalent telescope based on Earth on a good night.
	``You'll hear a lot of cheering if that happens,'' Weiler said.
	As the telescope orbited Earth Saturday, workers at the Goddard
Space Center beamed computer commands to the observatory to complete a
36-hour focusing process that began at 10 p.m. Thursday.
	The critical focusing process involved finding and locking onto
stars and minutely moving the telescope's 12-inch secondary mirror,
which is 16 feet from a 94-inch primary mirror. The secondary mirror can
move only a total of little more than one-tenth of an inch.
	Light enters the telescope, bounces off the primary mirror to the
secondary mirror mounted back near the opening and then down through a
hole in the primary mirror to a point where cameras and other
instruments can record the concentrated light.
	Ferried into space by the shuttle Discovery, the telescope is
expected to revolutionize astronomy by studying stars, galaxies and
planets in greater detail then ever before from its perch high above
Earth's atmosphere.
	By studying various forms of light, scientists hope the telescope
will answer fundamental questions during its 15-year life about the
birth of the universe, its current structure and age and perhaps
ultimate fate.
	An eight-month process of carefully turning on and adjusting the
telescope has fallen about 10 days behind schedule due to a series of
glitches with the sensitive telescope during the painstaking start-up.
	While most of the problems have been resolved, workers are still
trying to correct two unusual movements in the telescope, including a
vibration that occurs whenever the craft goes in and out of sunlight.

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.top
Subject: Hubble Trouble: Space telescope teething troubles
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 19 May 90 16:39:53 GMT
Lines: 87

UPI Spot Science Feature
	WASHINGTON (UPI) -- During ``Late Night with David Letterman'' last
Tuesday, the television comedian's nightly ``top 10 list'' was the ``Top
10 Hubble Telescope Excuses.''
	The list began with ``The guy at Sears promised it would work
fine,'' and included ``Some kids on Earth must be fooling around with a
garage door opener,'' ``There's a little doohickey rubbing against the
part that looks kind of like a cowboy hat'' and ``Ran out of quarters.''
	The No. 1 excuse, according to Letterman's list, was that a ``race
of super-evolved galactic beings are screwing with us.''
	Letterman's poke at the Hubble Space Telescope reflected a
perception that the highly publicized $1.5 billion space observatory has
been plagued by problems since it was placed into orbit last month.
	Scientists at the National Aeronautics and Space Administration
acknowledge the telescope's careful start-up has hit many unexpected
snags. But they argue work has proceeded relatively smoothly considering
the giant observatory is the most complicated machine of its kind ever
built.
	``I don't mean to be a Pollyanna,'' said David Leckrone, deputy
project scientist. ``But I do know that this time, right after launch,
early bugs and early problem-solving is very characteristic. I think we
would have been very naive to think it would have been any different.''
	The overall start-up process is about 10 days behind schedule and
engineers are still trying to fix two unusual movements in the
telescope, including a vibration that occurs whenever the 12-ton
telescope passes into or out of sunlight.
	But officials are confident the problems will be fixed, note that
work is actually ahead of schedule in some areas and predicted the
telescope could take its historic first picture of the heavens as early
as Sunday.
	``It's not a doom and gloom atmosphere,'' NASA astronomer Edward
Weiler said. ``Things are running pretty smoothly.''
	The telescope is expected to revolutionize astronomy by studying
stars, galaxies and planets in greater detail than ever before during 15
years of research from high above Earth's obscuring atmosphere.
	But before any research can begin, engineers at NASA's Goddard
Space Flight Center in Greenbelt, Md., and Marshall Space Flight Center
in Huntsville, Ala., must complete a painstaking eight-month process of
slowing turning on and adjusting the telescope's many complex systems.
	``We're in a goldfish bowl here,'' Leckrone said. ``Most flight
missions that NASA puts up in the very early days don't get the kind of
public scrutiny we're getting.''
	Officials were concerned the intense publicity had also raised
unrealistic  expectations for the first picture, an image of a
relatively nondescript star cluster planned as an engineering test and
not to produce any new discoveries.
	``This is not a test to make sure the telescope is working to its
full extent or will deliver on its promises,'' Weiler said. ``It's not
going to be exciting. It's going to be a black sky with white stars.''
	Much more important work will follow, he said.
	``Knock on wood, I think we've shaken out the major problems,''
Weiler said. ``One never knows what's going to happen in the future, but
I'm still totally confident this mission is going to be a success.''
	Problems with the telescope began the day the crew of the space
shuttle Discovery tried to placed it into orbit 381 miles above Earth on
April 25. Deployment was delayed when one of its two solar panels got
stuck.
	Once safely in orbit, engineers struggled with a series of
glitches, many involving the complex instrument's highly sensitive
safety systems, which sent the telescope into protective, time-consuming
hibernation several times.
	One of the most troublesome problems occurred when one of the
telescope's high-speed antennas became snared on a loose power cable,
preventing ground controllers from communicating properly with the
telescope.
	That problem, solved in part by building a Tinkertoy model, forced
engineers to permanently limit the antennas' movements, somewhat
inhibiting communications abilities. It will not, however, stifle
research.
	There were also several human errors. In one instance engineers
accidentally shut the telescope's door. On another occasion a simple
math error pointed the telescope in the wrong direction.
	``We'd like to think we're perfect human beings. But that isn't the
case. It has been frustrating. But on the other hand you're relieved it
was a simple human mistake and not something wrong with the telescope,''
Leckrone said.
	Morale among telescope handlers hit a low last weekend when an
unexpectedly bright star distracted the telescope's sensors, foiling the
first attempt to focus the telescope.
	``I was very down, pretty depressed,'' Weiler said.
	While the telescope's orientation and focusing has fallen behind
schedule, the craft has aired out faster than anticipated, allowing
engineers to turn on full power to two instruments and test others
earlier than expected.
	In addition, many systems officials were concerned about, such as
the craft's advanced power system, have performed flawlessly, Weiler
said.

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.top
Subject: Space telescope snaps first picture
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 21 May 90 04:25:03 GMT
Lines: 76

	GREENBELT, Md. (UPI) -- The historic first photos from the Hubble
Space Telescope were in better focus than expected, giving elated
scientists confidence the $1.5 billion observatory will live up to its
billing and revolutionize knowledge about the universe.
	``The launch was like an appetizer,'' said NASA astronomer Edward
Weiler. ``This is the soup and salad and now we're getting to the
entree.''
	Operating high above Earth's obscuring atmosphere, the 12-ton
telescope's electronic wide-field camera snapped two black-and-white
pictures of a Milky Way star cluster Sunday and after computer
processing, the camera's chief scientist said the digital images were
two to three times sharper than expected.
	``I'm tickled pink with what we've seen today,'' astronomer James
Westphal said. ``We were expecting to see something that looked pretty
much like a ground-based picture. So the fact that we're seeing
something that is really obviously sharper really pleases us a whole
bunch.''
	The space telescope was launched from the shuttle Discovery April
25 and despite early glitches that threw the instrument's activation
about 10 days behind schedule, Westphal said, ``We're really doing great
by my perception.''
	``I'm really impressed with the speed at which this thing is coming
together,'' he said. ``I'm just pleased as I can be about it. We could
do a bunch of science right now.''
	But the photos beamed to the Goddard Space Flight Center control
room Sunday were only to test the focus of the telescope and the
operation of the wide-field camera, one of six instruments on board the
costly observatory. Routine science observations are not scheduled to
begin for another seven months.
	When the engineers get done, however, the telescope's focus will be
seven times sharper, yielding stellar images that will be 50 times more
compact than those seen Sunday. But the first ``rough focus'' pictures
were exciting nonetheless.
	``It's the first picture of 10,000 or 20,000 or 30,000 pictures to
be taken over 15 years,'' Weiler said. ``It's the first photons coming
down from a spacecraft that will ultimately make major discoveries and
reshape our vision of the universe.''
	As the 12-ton observatory orbited 381 miles above Jayapura, New
Guinea, the shutter of the wide-field camera opened for one second at
11:12 a.m. EDT Sunday to take the first black-and-white picture. That
photo and another exposure lasting 30 seconds were stored on magnetic
tape and relayed to the ground about 1:32 p.m.
	The first digital image was an underexposed shot of the Milky Way
star cluster known as NGC 3532, a nondescript group of stars visible
from the Southern Hemisphere.
	But the second 30-second picture showed dozens of suns in the star
swarm. The star images were slightly elongated but, overall, the quality
was better than expected given that engineers have not yet finished
focusing the telescope's near-perfect optical system.
	A comparison with a ground-based photo of the same stars showed the
space telescope was close to right on target and in better focus than
anyone expected. One star, for example, clearly showed up as a double
star when it appeared as a somewhat lopsided single sun in the
ground-based view.
	``How `bout them apples,'' Westphal said amid cheers as the two
images were projected on side by side on a computer screen. ``Very
nice.''
	The target for the first-light picture was a 3 billion-year-old
star cluster located about 1,500 light years from Earth in the Southern
Hemisphere constellation Carina. A light year is the distance light
travels in a year at 186,000 miles per second, about 5.8 trillion miles.
	The first photos were not intended to generate any new discoveries,
and project scientists worried that intense media scrutiny had raised
public expectations for a more spectacular photograph.
	NGC 3532, however, was chosen for the first-light photos simply
because it provided a suitable field of stars -- pinpoints of light -- to
test the telescop's focus.
	Over the next seven months, the telescope's optical system will be
precisely aligned, giving the instrument 10 times the clarity of
ground-based observatories and allowing astronomers to peer deeper into
the universe than ever before.
	The space telescope was designed to operate for at least 15 years,
studying various forms of light in the hope of gleaning clues to answer
fundamental questions about the birth of the universe, its current
structure, its age, size and perhaps its ultimate fate.

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: HST Update - 05/17/90
Message-ID: <[email protected]>
Date: 17 May 90 21:38:06 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 24

                  Hubble Space Telescope Update
                          MAY 17, 1990
 
The Hubble Space Telescope successfully completed the
pattern match portion of a 38-hour command load last night.  The
telescope's fine guidance sensors observed stars during each
pattern test, and confirmed acquisitions of guide stars in six of
the seven tests.  The pattern match sequence is a test between
predicted star patterns and points of light actually observed by
the telescope's fine guidance sensors.   "First light," the first
image taken by a science instrument, will occur sometime during the
second part of Bootstrap Phase A -- probably not earlier than
Sunday afternoon, according to Dr. Edward Weiler, Hubble Space
Telescope mission scientist.  Operators believe the quality of the
image should be comparable to images received by ground-based
telescopes on a dark night.  When the telescope is fully
operational, engineers expect to see more than 10 times better than
ground-based observations.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

==============================================================================
From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/18/90
Message-ID: <[email protected]>
Date: 18 May 90 21:46:31 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 28

                   Hubble Space Telescope Update
                           May 18, 1990
 
     Ground operators commanded the Hubble Space Telescope
through its pointing control and mirror focusing paces today,
a repeat of a series of commands that will lead up to the
first optical images from the telescope, called "First Light,"
probably this weekend.
 
     Goddard Operators began a 36.5-hour re-run of Bootstrap Phase A,
Part One, at 10 p.m. EDT Thursday night.  As of 8 a.m., EDT Friday, two
data takes were successfully completed, each with nine successes
in nine attempts to locate and lock onto line-of-sight, or target,
stars.  Based on the data from scans performed during the first
data take, operators adjusted the secondary mirror focus to 1.4 arc
seconds.  Further refinement of the focus will be done as other
command loads are uplinked to the telescope.
 
     Engineers are continuing to gather and analyze data on three
issues: a slight roll in one axis of the telescope, small
vibrations in the telescope when it passes between night and day,
and slight telescope attitude drift.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.gov.agency,clari.news.top
Subject: Scientists elated with Hubble
Keywords: space, science, air transport, transportation,
Message-ID: <[email protected]>
Date: 21 May 90 22:09:59 GMT
Lines: 66

	WASHINGTON (UPI) -- The first photos from the Hubble Space Telescope
are in better focus than expected, giving scientists increased
confidence the $1.5 billion observatory will live up to its billing to
revolutionize astronomy, officials said Monday.
	NASA astronomer Edward Weiler said the telescope's historic ``first
light'' photos of a Southern Hemisphere star cluster were studied
overnight and the quality of the pictures is even better than he
initially thought, proving Hubble's near-perfect 94.5-inch mirror came
through launch in good condition.
	``It's given us more confidence that the mirror's in good shape and
survived the launch very well,'' Weiler said. ``Most of the light (from
the stars) is concentrated in the center of the image, which is exactly
what you'd expect from a very high-quality mirror that is just slightly
out of focus.''
	Orbiting high above Earth's obscuring atmosphere, the 12-ton
telescope's electronic wide-field camera snapped two black-and-white
pictures Sunday of a star cluster known as NGC 3532 to test the
instrument's focus.
	After computer processing, astronomer James Westphal, the camera's
chief scientist, said the digital images were two to three times sharper
than expected. Over the next two months, the telescope's mirrors will be
adjusted in tiny increments to get the focus seven times better.
	But even the ``rough focus'' pictures taken Sunday were impressive.
In a 30-second exposure, a double star was clearly apparent while a
ground-based photo of the same region showed a single somewhat elongated
image.
	Weiler said improvements overnight in the contrast of the
first-light photos improved the picture so much it will ``knock your
socks off.'' The improved picture was to be released Tuesday.
	Over the next week, technicians at NASA's Goddard Space Flight
Center telescope control room will continue to adjust the telescope's
focus and work to resolve tiny errors in the instrument's pointing and
control system that are causing it to wobble very slightly.
	No more pictures are expected to be released for several weeks.
	``We will be doing some more images, but they will be really where
we (can) fit them in,'' Weiler said. ``For the next two or three months,
we're really trying to get the fine focus down, the fine alignment down.
	``But if we get an opportunity to take an image here or an image
there, we'll do it over the next two or three months once we are in fine
focus. The next time we release photos we want them to be what the space
telescope can really do. We don't them just to be engineering images.''
	He said public and media impatience to see a first-light photo put
pressure on the telescope control team, blowing the significance of the
pictures out of proportion.
	``It became a very big milestone in a program that has a lot of
very big milestones and it was never meant to be a big milestone,'' he
said. ``It was meant to be a routine qualitative test of the focus.''
	Still, he said, ``We're all very glad we did it because it lifted
our morale quite a bit.''
	Over the next seven months, the telescope's optical system will be
precisely aligned, giving the instrument 10 times the clarity of
ground-based observatories and allowing astronomers to peer deeper into
the universe than ever before.
	The space telescope was designed to operate for at least 15 years,
studying various forms of light in the hope of gleaning clues to answer
fundamental questions about the birth of the universe, its current
structure, its age, size and perhaps its ultimate fate.
--
This, and all articles in this news hierarchy are Copyright 1990 by the wire 
service or information provider and licenced to Clarinet Communications 
Corp.  for distribution.  Except for free samples, only paid subscribers 
may access these articles.  Any unauthorized access, reproduction or 
transmission is strictly prohibited.  We will reward the first provider of 
information that helps us stop violators of this copyright.  Send reports 
to [email protected].  

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 05/21/90
Message-ID: <[email protected]>
Date: 21 May 90 17:50:30 GMT
Sender: [email protected]
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 26

                  Hubble Space Telecope Update
                         May 21, 1990
 
     The first picture taken by the Hubble Space Telescope yesterday was
supposed to be just an engineering test, but it surprised scientists
by revealing an unsuspected double star.  The inaugural photo sequence
showed bright, crisp stars against a black background and clearly
revealed as a double star an object which had previously only been
suspected as being a doublet.
 
     James Westphal, wide field and planetary camera investigator, said
"the images were at least twice, if not three times better than expected.
We could get lots of science out of this right now."
 
     There was little evidence of drift or unwanted movement in the longer
exposures, showing the telescope's stabilizing gyroscopes to be working.
Over the next seven months, the telescope's optical system will be
precisely aligned giving the instrument 10 times the clarity of
ground-based observatories.  Picture quality is expected to improve
several times as Hubble loses air and water from its Earth days.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

	CAPE CANAVERAL, Fla. (UPI) -- The Hubble Space Telescope locked
securely onto a celestial target during the first test of its most
advanced guidance system, the project's lead scientist said Tuesday.
	The successful ``fine-lock'' with the telescope's ``fine guidance
sensors'' over the weekend encouraged engineers to think they can
overcome lingering vibrations in the 12-ton telescope and begin final
work to focus the instrument's near-perfect optical system, said NASA
astronomer Edward Weiler.
	``We held fine-lock for an hour or two and held it through the
day-night transition,'' said Weiler as he awaited launch of the space
shuttle Columbia on a 10-day mission aimed at complementing the Hubble
telescope.
	``The only time we achieved fine-lock before that was just for a
few seconds and then we got knocked out,'' he said. ``This time we
achieved fine-lock and we held it for an hour or two.''
	The $1.5 billion telescope was placed into orbit April 25 by the
crew of the space shuttle Discovery for a 15-year exploration of the
universe that is expected to revolutionize astronomy.
	Since being deployed, NASA engineers have struggled with a series
of problems as they carefully activated the complex observatory's many
systems.
	Most of the problems have been solved but analysts were still
trying to eliminate two small abnormal movements in the telescope,
including a tiny vibration that occurs whenever the telescope goes into
or out of sunlight as it sails around the planet at some 17,000 mph.
	The key to the telescope's operation is its ability to firmly lock
onto astronomical targets, allowing its instruments to take long
exposures of extremely dim objects.
	Design specifications call for a guidance accuracy of seven
thousandths of an arc second, which translates into being able to keep a
laser beam inside the diameter of a dime at a distance of 200 miles, the
distance between New York and Washington.
	Before this weekend's test, engineers had only been able to achieve
``coarse-lock'' with the telescope, which is less accurate, Weiler said.
	``They've been working now, looking at all the data from all the
glitches. They've been changing gains and changing thresholds ... and
just working the system and finding out how this system needs to be
tweaked to perform the way it's supposed to perform,'' he said.
	``We're bringing down the amount of glitches,'' he said. ``(The
movements are) getting smaller and smaller. Instead of being able to
hold it on a dime in New York, maybe a quarter. And we're bringing it
down.''
	The success with the fine-lock system means engineers could begin
the second and final phase of precisely focusing the telescope so the
instrument can study stars, planets and galaxies in more detail then
ever before.
	``That's our goal for the next week or two -- to get it into
focus,'' said Weiler. ``People are pretty upbeat.''

From: [email protected]
Newsgroups: clari.tw.space,clari.news.aviation
Subject: Hubble telescope locks onto target
Keywords: space, science, air transport, transportation
Date: 29 May 90 16:39:32 GMT

	CAPE CANAVERAL, Fla. (UPI) -- Engineers believe they have solved an
ongoing problem with the Hubble Space Telescope that has plagued efforts
to get its ultra-accurate guidance system operating properly, officials
said Monday.
	Deputy program manager Jean Olivier said ongoing trouble getting
the telescope to lock onto guide stars apparently was the result of
computer programming that prevented the instrument from lining up
properly on the correct targets.
	Instead of orienting guide stars on the ``centerline'' of the
guidance sensors' fields of view, the telescope's computer was ignoring
such stars unless they happened to end up near the centerline by chance.
	In a weekly teleconference with reporters across the nation,
Olivier said work to check out the $1.5 billion telescope should proceed
more smoothly from now on.
	``We're still behind two or three weeks all in all, I would
guess,'' Olivier said from the Goddard Space Flight Center in Greenbelt,
Md. ``The process from here on out, I feel the last thing we found on
the (guidance problem) has been one of the things that's plagued us on
the whole orbital verification activity and has hampered everything
we've done.''
	The Hubble Space Telescope was released from the shuttle Discovery
into a 380-mile-high orbit April 25 to kick off a 15-year mission to
explore the depths of the universe. But a series of problems has plagued
the telescope's orbital activation.
	Many of those problems were related to the telescope's inability to
find guide stars. By locking onto and tracking such stars, the
telescope's four five primary instruments can make time-exposure
observations.
	``I've added up about 14 problems we've had that are totally
independent of one another just that had to do with our inability to
acquire guide stars,'' Olivier said. ``Every time we solved one of these
we thought it was the last one.
	``All I can say now is in the past, as we would solve the problem
it would be just a few hours before we had another problem. The positive
side of what I'm telling you is since we've discovered the (centerline)
problem we've had a dramatic change in the ability to acquire guide
stars.''
	Two problems involving the stability of the telescope have been
resolved by getting the observatory's optical system in better focus.
	Olivier said early problems with wobbling were caused by the
telescope's guidance system trying to lock onto out-of-focus stars. Such
blobs of light caused the guidance system to ``search'' for the target's
center, which caused the telescope to wobble slightly.
	As the focus was improved, however, the telescope's stability
improved dramatically.
	Only one such problem remains to be resolved: When the telescope
moves into and out of sunlight, temperature-induced oscillations in the
observatory's big solar panels apparently cause a minor wobble. What
will be done about that problem remains to be seen.
	``I feel we know a lot about the spacecraft, obviously more than we
did, and I feel pretty confident the kinds of things we find in the
future will be more isolated than the kinds of things we've been running
into in the past several weeks,'' Olivier said.


From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.top
Subject: Space telescope problem resolved
Keywords: space, science, air transport, transportation, air force,
Date: 4 Jun 90 22:21:26 GMT

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Date: 7 Jun 90 15:23:48 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                          Hubble Space Telescope Update
                                June 5, 1990
 
     A rather uneventful past 24 hours for HST except for the Scientific
Instruments (SI's).  Bootstrap Phase B ran to completion.  Guide star
acquisitions continued to run rather smoothly for except for one set of 3
reacquisitions:  an ephemeris was uploaded to HST, this requires the velocity
aberration compensation to be turned off and, somehow, it did not get turned
back on.  By the time this was discovered three reacquisitions had failed.
Once the aberration correction was reactivated acquisitions again were
successful.  Fixed Head Star Tracker (FHST) updates continue to work well.  SI
activities in the past 24 hours had the Goddard High Resolution Spectrograph
(GHRS) and High Speed Photometer (HSP) turn on and the Wide Field
Planetary Camera (WFPC) take two more Planetary Camera (PC) images in support
of Bootstrap Phase B.  SI activities will continue until 2:30 PM (16:30 UT)
Wednesday when a scheduled 64 hour rerun of Bootstrap Phase B part 3 begins.
 
     Bootstrap Phase B, parts 2 and 3, completed yesterday but no new data was
gathered so there have been no mirror movements.  Part 3 (coarse wavefront
measurement) is going to be rerun starting Wednesday at 2:30 PM EDT (16:30 UT).
Great caution has been taken to avoid problems that occurred during the first
run, increasing the execution time to 64.5 hours.  Mirror adjustments will be
made at the conclusion of this run (Saturday).  The WFPC team has been
analyzing the most recent PC images.  Of greatest interest is that there is
better data to support the claim that the structure of the broad "disk"
component of the stellar images in the PC varies dramatically over the field of
view.  As of the moment they do not know the cause but the suspicion is that
this is due to variable obscuration of the beam by telescope and camera
structures.  A quantitative model is being tested so more on this later.  The
statement on PC8 that it "did not return good data" now has an explanation: at
current warm temperatures the chip has a high background and the data was of
too low a Signal-to-Noise Ratio (S/N) to use, i.e. it is NOT a problem.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Update - 06/06/90
Date: 8 Jun 90 05:38:44 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                            Hubble Space Telescope Update
                                  June 6, 1990

     The Hubble Space Telescope (HST) went through another uneventful day
in orbit, except for the Scientific Instruments (SI).  The Faint Object
Camera (FOC) went through a F/96 Stability test.  All indications are that
the test has run well.  The FOC is the first SI to complete the Orbital
Verification Part 1 phase of the HST commissioning period.  The High Speed
Photometer (HSP) completed its Detector Dark Count proposal and all went well.
A 24 hour Health and Safety load has been inserted in the schedule beginning
at 2:30 PM EDT on June 6.  The Bootstrap Phase B SMS, now running a total of
74 hours, will start at 2:30 PM EDT on June 7.

     Of the 60 power panels in the telescope's arrays, 1 is not working and
1 works intermittently (faulty connections are thought to be the problem),
the remaining 58 are exceeding or meeting power expectations.

     The Fixed Head Star Tracker (FHST) calibration has been simplied when a
single field was identified such that the FHST can simultaneously see 2nd
through 7th magnitude stars.

     The Wide Field Planetary Camera (WFPC) is in full operate mode.  No
activities occurred and none are expected for the next 24 hours.

     The Goddard High Resolution Spectrograph (GHRS) had its second High
Voltage turn on the morning of June 5.  The test was successful with no
anomalies.  The Low Voltage Telemetry checks will be continued to run about
once every 24 hours.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Date: 8 Jun 90 16:26:14 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                  Hubble Space Telescope Update
                          June 8, 1990
 
     All of the Hubble Space Telescope's instruments were reported to be in
good order, with no problems. The Faint Object Spectrograph (FOS) reports
a pressure of 7e-6 torr and engineering reports that the satellite is 9.9
degrees off optimum power angle.  The Faint Object Camera (FOC) has taken
125 internal images.
 
     Two Wide Field Planetary Camera (WFPC) pictures were taken last night
The field was in Carina, just as the pictures were from June 3 and June 4.
A 10s and a 100s second exposure was taken. The field was supposed to have
been shifted slightly from the June 3 location to bring our one bright star
into the center of PC5, but no slew was put into the system; consequently
the star locations are nearly identical to that of the June 3 exposures (the
stars moved by about 9 pixels).  An additional picture will be taken on
Sunday. Currently, Part 3 of Bootstraph Phase B is in effect.  If this goes
successfully, there will be a secondary mirror movement before the next
picture.  It was discovered that a guide star pair for the WFPC supporting
images may have failed due to a confusing field.  A new guide star pair was
chosen.
 
     A software problem may exist in the Fixed Head Star Tracker (FHST) in
the choice of the reduced field of view (~1 x 1 deg) found within the 8x8 deg
window.  In addition, there are problems with near neighbors and threshold
levels.  In a test yesterday, it was found that 15 out of 60 updates failed
due to confusion with a neighbor star. Another FHST concern is possible
orbital position dependent noise.  Scattered light was suggested as a
possibility for this and a 24 hour test of the FHST was proposed where they
would map the noise as a function of orbital position.  The star catalogue
used by the FHSTs still remains a concern.  The FHSTs on the telescope needs
one star, assuming no neighbors, for its positional verification.  The SMM
satellite was found to use three stars, checked with on-board software.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Date: 11 Jun 90 16:15:38 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.


                      Hubble Space Telescope Update
                             June 9, 1990
 
     A 24 hour Health and Safety load was completed and a 74 hour Bootstrap
Phase B part 3 (Coarse Wavefront Measurement) was begun.  Bootstrap Phase B
part 3 is off to a good start.  Out of 15 guide star acquisition and
reacquisitions attempts 14 acquired fine lock, 3 of those lost lock at the
terminator but reacquired and held fine lock after ~2 minutes.
 
     The sensor 1 failure was attributed to the loss of TDRSS (ground hardware
problem) at the time the Fine Guidance Electronics (FGE) were being reset,
precipitating the failed lock.  Overall, the Fine Guidance Sensor (FGS)
behavior was excellent with all acquisition and reacquisitions succeeding.
Loss of lock at the terminator is still occuring but with reacquisition and
fine lock occurring in less then 2 minutes.  The wavefront data in hand looks
good enough to do a mirror adjustment; while this is the most likely action,
a final decision on whether or not to move the mirror will be made pending
further analysis of the recent test data.
 
     On June 12 a new version of the SKYMAP catalog for the Fixed Head Star
Tracker (FHST) updates will be used.  Hopefully, this will improve the
effectiveness of the FHST's.
 
     More Wide Field Planetary Camera(WFPC) images were taken, nothing had
changed from the last time the WFPC was exercised, and the images are almost
identical to the earlier images.
 
     Since June 8, three wavefronts were attempted.  One failed because of
the FGS failure to acquire, one gave good data, and one probably gave good data
(it is still being processed).  The disturbance produced by the terminator
crossing is causing problems in the wavefront measurements.  The disturbance,
even avoiding the terminator region, introduces enough of an extraneous jitter
that it can overwhelm the wavefront measurement.  Even with the terminator
problem it looks as if there should be enough data to make an alignment/focus
adjustment by June 11 at the latest.
 
     The first light for the Faint Object Camera (FOC) is due sometime during
the week of June 18.
 
     The Goddard High Resulution Spectrograph (GHRS) is in hold.  A possible
radiation detector diode failure was reported -- one of the diodes was
measuring low counts while in the South Atlantic Anomaly (SAA).
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation
Date: 11 Jun 90 22:53:21 GMT

	WASHINGTON (UPI) -- Particles from Earth's radiation belts are
periodically garbling the computer memory of the Hubble Space
Telescope's guidance system, further slowing the observatory's start-up,
officials said Monday.
	But computer programming changes should correct the problem and
compensate for a small wobble in the $1.5 billion telescope that occurs
whenever the instrument sails into or out of sunlight, officials said.
	``It's kind of a frustration to have to work around (the
problems),'' said deputy program manager Jean Olivier during a telephone
briefing for reporters from the Goddard Space Flight Center in
Greenbelt, Md.
	The space shuttle Discovery placed the telescope into orbit 381
miles above Earth on April 25 for a long-awaited 15-year mission of
exploring the universe in greater detail than ever before.
	Engineers with the National Aeronautics and Space Administration
have battled one problem after another in the early stages of an
eight-month process of carefully calibrating and adjusting the
complicated observatory's instruments and optical system.
	Most of the problems have been resolved but work to focus the
telescope's near-perfect optical system and to fine-tune the
observatory's guidance system has fallen about three weeks behind
schedule.
	One of the remaining problems occurs when the 12-ton telescope
passes through the South Atlantic Anomaly, a zone over the South
Atlantic Ocean off the coast of Brazil in which the so-called Van Allen
radiation belts dip close to Earth.
	``The spacecraft passes through that periodically,'' Olivier said.
``When it passes through there is a pretty high radiation environment.
The fine guidance electronics do become contaminated.''
	Even though NASA engineers were aware of the anomaly and took steps
to shield the telescope from its effects, the precautions apparently
were insufficient, Olivier said. ``Apparently we evaluated it wrong,''
he said.
	When it flies through the South Atlantic Anomaly, the telescope is
bombarded by radiation from the Van Allen belts, made up of charged
particles from the sun that are trapped by Earth's magnetic field.
	Such radiation can cause problems with the instrument's computer
system, garbling data used by the guidance system to keep the
observatory precisely pointed.
	Engineers now are turning the telescope's guidance computer off,
then back on again after passage through the radiation zone.
	To correct the problem once and for all, engineers are devising
computer programming changes that will allow the guidance system to be
constantly updated by another computer that is immune to the
interference. That way, even if interference occurs, bad data will not
be in the system long enough to cause stability problems.
	The telescope's stability is crucial to successful astronomical
observations. But every time the telescope passes from Earth's shadow
into sunlight, or vice versa, the observatory begins wobbling slightly.
	Olivier said engineers have determined that metal poles in the
telescope's energy-collecting solar panels flex as much as 10 inches
during this transition because of temperature-induced expansion and
contraction. That, in turn, causes the spacecraft to wobble slightly.
	The vibration has delayed getting the telescope fully focused
because work is interrupted periodically until the vibration, which
lasts as long as 20 minutes, stops, he said.
	``This solar array dynamics is beggining to rear its head as a
limiting factor,'' Olivier said. ``We probably would have been further
along ... if this added requirement ... had not been with us.''
	To correct the problem, engineers are writing a new computer
program that will cause the telescope to move in a fashion that
precisely cancels out the motion induced by the solar panels.
	But it will take about two months to complete the work, Olivier
said, adding that ``we'll be hampered until this is corrected,'' he
said.

                     Hubble Space Telescope Update
                             June 14, 1990


     Bootstrap Phase B part 3, coarse wavefront measurements, finished on
June 10.  The data obtained from this test was felt adequate enough to
provide an improvement in focus but not in alignment.  Data from the
independent measurements did not fully agree on where the focus was so a
decision was made to go with the determination that had the best
Signal-to-Noise Ratio (SNR).  A command was issued to move the mirror 24
microns (less than 1 wave) or equivalent to ~0.5 arcsec change in the image.
Planetary Camera (PC) pictures were then obtained.  These new "after" images
look different from the "before" image, but most of the difference is due to
a small attitude change that was put in to move a bright star to the center
of the image.  Quantitative analysis of the image show no statistically
significant difference between the two images.  The likely explanation of
this lack of difference was that the secondary was moved too much; it was
moved through focus to a position roughly the same distance from focus, but
on the other side of focus, as it was before the movement.  The next phase of
the focusing process, Bootstrap Phase B part 4, Exit Pupil Calibration,
begins on June 12 and runs through June 15.  The expectation is that after
this test the mirror will be moved in focus and aligned.  More PC pictures
will be obtained on June 15.

     The Faint Object Spectrograph (FOS) is in the process of slowly turning
their High Voltage (HV) on, all is going well so far. The High Speed
Photometer (HSP) is running Detector Dark Count tests, Detector 4 tests have
finished, Detector 1 testing is still in progress.  So far, no anomalies have
been reported.

     No new results from the analysis of the Pointing Control Subsystem (PCS)
problems.  Fixed Head Star Tracker (FHST) testing will be occurring a few
times per week for a while.  The Wide Field Planetary Camera (WFPC) is in
full operate mode. There will be more pictures this week in support of
Bootstrap Phase B focus and alignment.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

                          Hubble Space Telescope
                             June 16, 1990
 
     First analyses of the Planetary Camera (PC) images are in, essentially
they confirm the first visual impressions of the data.  A significant change
in the image quality did occur after the focus movement on June 14: encircled
energy plots show that the core of the images narrowed and there was an
expansion of the faint halo.  Both the images and the encircled energy plots
show clear improvement.  The images taken after the tilt and decentering
movement of the secondary show essentially no significant difference between
the before and after images.  Why there was no change is still not understood.
Resolution of the puzzle must await further wavefront measurements, now
scheduled for June 18.  Scientific Instrument (SI) activities have gone
extremely well: Faint Object Spectrograph (FOS) recovered from safemode and
all Goddard High Resolution Spectrograph (GHRS) testing has gone
extraordinarily well.  Faint Object Camera (FOC) first light is still
scheduled to begin early on June 17, with the first of the 10 images to be
taken at 3:40 AM EDT. Tape recorder dumps will be scattered throughout the
FOC run.
 
     Nothing new on any of the Pointing Control Subsystem (PCS) problems.
The mirror movements on June 15 required a new alignment matrix to be
constructed since it changed the relationship between the Fixed Head Star
Tracker (FHST) and Optical Telescope Assembly (OTA) optical axes.  This was
successfully done and the changes were what was anticipated.  FHST updates
have been working very well but this should not be taken as proof that the
FHST problems are solved.  It has been pointed out that virtually all of
the updates have been at the same few attitudes, attitudes that have been
very thoroughly checked out by the Astrometry team.  A better assessment
of how the FHST's are doing can be done once the spacecraft is moved to new
attitudes.
 
     Analysis of the past few days mirror movement was given above.  The image
quality was significantly improved by the focus movement but uneffected by the
subsequent tilt and decentering.  It is known that this latter movement
actually did occur because of the change in the FHST/FGS (Fine Guidance
Sensor) alignment matrices.  Why it had essentially no impact on the image is
under study.  No mirror movements will be made between now and the FOC first
pictures.  On June 18 more wavefront measurements will be made to check out
the optics in a more rigorous way.  All next week (Monday through Sunday)
Bootstrap focus and alignment proposals will be only HST activity.
 
     FOC is still in hold on the B side awaiting FOC first light.  The FOC
first light will be 10 images obtained with the F/96 side of a field in
NGC 188 containing two astrometric standards.  Each exposure is 10 minutes
in length (through 6 magnitudes of ND filters). The purpose of the images is
to locate and map the 22 arcsec Field of View (FOV).
 
     FOS is in hold, having successfully recovered from safemode.  Nothing is
planned for the FOS for the next few days.
 
     GHRS has had a very active and successful weekend.  Activity on June 15
was all done on Side 1, Side 2 testing starts on June 16. Detailed analysis
of the data is in progress.  Preliminary comments: High Voltage (HV) on
went very well, the focus was found to be identical to that found in thermal
vacuum tests, pulse height results look fine, and all apertures were seen
during the bright earth observation.  If the next set of GHRS tests go well
this will complete their OV 1 activities.
 
     The Wide Field Planetary Camera (WFPC) is in full operate mode.
No more PC pictures are scheduled until next week.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

                     Hubble Space Telescope Update
                              June 18, 1990
 
     The Faint Object Camera (FOC) first light went rather well, at least as
far as the performance of the FOC.  The first light effort was plagued by
persistent Fine Guidance Sensor (FGS) loss-of-lock due to terminator crossings,
but good data was obtained.  Quantitative data is still, for the most part,
unavailable but the expected stars were seen and data suggests an image that is
very similar to that seen by Wide Field Planetary Camera (WFPC): a very sharp
core surrounded by a large halo.  The FGS's experienced frequent loss-of-lock
at terminator transitions over much of the day, there was even one failed
acquisition in fine lock.  The behavior of the FGS's during this period is
under study, but it looks as if this sort of FGS loss-of-lock will occur with
some regularity until the terminator disturbance "fix" is installed around
August.  Scientific Instruments (SI) activities continued to go extremely
well with no anomalies being reported.  Bootstrap Phase B, part 5A has just
begun.
 
     The performance of the FOC during the "first light" run was perfect.
The only problem encountered was frequent FGS loss-of-lock followed by
reacquisition induced by terminator crossing.  The FOC shutter is coupled to
the spacecraft "take data" flag, i.e. if the FGS's were not in fine lock then
the shutter was not to be opened.  The effect of the frequent
loss-of-lock/reacquisition was to keep the shutter closed more than the FOC
team desired: only 4 of the 10 exposures were for the full 10 minute requested
duration.  The data was compromised somewhat by the shorter and unpredictable
exposure times but, overall, it appears that all the questions that the test
was intended to answer were successfully answered.  Specifically: early
analysis of the data show that the position of the 22 x 22 arc second aperture
is within 4 arc seconds of its expected location, all the expected stars were
seen at about the correct intensities (once you account for the light in the
image halo), stellar images look very much like the WFPC images, having a
very sharp core (< ~2 pixels) and an extended, asymmetrical (~1 arc second)
halo, and the FOC zoom feature was successfully tested.  All and all the
images look very much like the most recent WFPC images.  The FOC team seems
extremely happy with what they are seeing.
 
     Nothing new on any of the Pointing Control Subsystem (PCS) problems other
than the occurrence of frequent loss and reacquisition of fine lock over the
past 24 hours.  The new alignment between the FGS's and the Fixed Head Star
Tracker (FHST) and gyros appears to have worked very well.  FHST updates are
still working with good regularity.
 
     The only new results in the HST focusing were that new calculations
suggest that the "tendrils" seen in the WFPC images are fully understandable
in terms of the interaction of the aberrations in the incoming beam
interacting with the known pupil function (spiders, pads, obscurations).
Thus, the expectation is that the image quality should improve dramatically as
the diffraction limit is approached.  All this week (Monday through Sunday)
Bootstrap Phase B focus and alignment proposals will be only HST activity.
 
     The Faint Object Spectrograph (FOS) is in hold.  Best guess as to when
the FOS will try their High Voltage (HV) on is about one week from now.
 
     The Goddard High Resolution Spectrograph (GHRS) had another very active
and successful day.  Detailed analysis of the data is in progress.
Preliminary comments indicate that all went very well and that there were no
anomalies.
 
     The High Speed Photometer (HSP) is in hold with no activities planned
for the next 24 hours.
 
     The WFPC is in full operate mode.  The next WFPC images are scheduled for
3 PM EDT on June 19.  More images are due later this week.  The images this
week will be a repeat of the set of 10 images through 3 different filters.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

                            Hubble Space Telescope Update
                                  June 20, 1990


     The telescope's mirror was moved last night but it was commanded back
to the position it was in before the previous tilt and decentering.  Wide
Field Planetary Camera (WFPC) images taken after the move appear to confirm
that the secondary mirror is back where it was 5 days ago.  This decision was
reached after extended discussions over the state of the current focus and
how next to proceed.  One of the primary reasons to move the mirror back to
the previous position was that it has become apparent that since the tilt
and decentering movement the Fine Guidance Sensors (FGS's) have had trouble
holding fine lock, even on stars that they had held in fine lock before.
Without the ability to go into fine lock the necessary wavefront sensor (WFS)
data cannot be obtained.  So, it was decided to go back to the previous
position and gather more WFS data.

     The Astronomy team (AST) reported that they found the phantom star that
failed the guide star acquisition for the first WFPC 10-image test.  The
Faint Object Camera (FOC), the Faint Object Spectrograph (FOS), the Goddard
High Resolution Spectrograph (GHRS) and the High Speed Photometer (HSP) are
all on hold.

     The WFPC is in full operate mode.  The attempt to get 10 images through
3 filters went very well as did the two Bootstrap support images.  The next
WFPC images are scheduled for June 21 at around 3 PM EDT.

       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

                          Hubble Space Telescope Update
                                  June 21, 1990
 
     Most of the activity for the past 24 hours has been directed toward the
state of the focusing the Hubble Space Telescope (HST).  It does appear that
problems are being sorted out and plans of attack being formulated.  It is
apparent that one of the major obstacles to getting HST focused is the low
quality and quantity of the enlisting data.  As such, the major line of attack
is to modify the data gathering procedures to improve the data quality and then
gather more data.  So the next few days have a fair amount of wavefront sensor
measurements and Wide Field Planetary Camera (WFPC) pictures to better
define the degree of focus of HST.  Guide star fine lock was not going well
(failed acquisitions and frequent drop outs from fine lock) so real time
commands were issued to reinsert the 2/3 aperture.  Fine lock acquisitions did
improve but there were still some problems.   A new type of loss of fine lock
in the Fine Guidance Sensor (FGS) occurred: loss of lock induced by the South
Atlantic Anomaly (SAA) (not "bit flips") -- the failure is under study.  All
is quiet with the other spacecraft subsystems, including the Scientific
Instruments (SI).
 
     One fine lock dropout was found to occur as a result of passage through
the SAA.  This is the first time that SAA passage caused a loss of lock.  The
problem is under investigation.  WFPC found that one of their images was
obtained in the middle of a terminator disturbance and show double images plus
evidence of rapid jitter.  The image was passed on to Lockheed Pointing Control
Subsystem (PCS) people for analysis.
 
     The HST focus was again the major topic of discussion in the past
24 hours.  There now seems to be general agreement that the data on hand is far
from ideal, being ambiguous and contradictory in many cases.  In essence,
reanalysis of the old data appears to have diminished confidence in the derived
conclusions.  Thus, the major effort of the next few days will to take more
data, taking specific care to improve the data quality.  A few additional tests
are also being run.  The secondary mirror was moved to a position significantly
out of focus (~10 waves toward the primary), a series of WFPC pictures are now
being taken with the mirror in this position.  Later, the secondary will be
moved again, to a point ~5 waves from focus (toward the primary) and more WFPC
images will be taken.
 
   The secondary will then be moved back to the position it was in yesterday.
On June 22 a new focus run will begin, Bootstrap Phase B part 5c, with more
wavefront sensor (WFS) measurements.  Focus runs (WFS measurements, possible
mirror movements, and WFPC images) will be executed through the weekend and
into the beginning of next week.  The expectation is that much of next week
will also be filled with more focus runs.  A lot of new data will be coming
in over the next few days, the results from the "way out of focus" images
should be interesting as should the new WFS measurements.  One point of
discussion regards what focus star to use: iota Car can only be used for a
short time more (~5 to 10 days) before it becomes too close to the sun.
Switching to another star requires a major effort to select the star, and
a repeat of earlier Bootstrap SMS in order to get the alignments needed to
successfully use the WFS measurements. Iota Car will continue to be used
at the present time.
 
     Nothing new on the analysis of the 10 Faint Object Camera (FOC) images.
A press release is expected shortly.
 
     The Astrometry Team (AST) is the most active team with the focus tests
running.  They are supporting Fixed Head Star Tracker (FHST) calibration
planning, assisting in finding a new focus star, and checking out fields for
the FGS's.
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

                           Hubble Space Telescope Update
                                 June 24, 1990
 
     In the past three days not a lot has happened with the Hubble Space 
Telescope (HST) other than a lot of focus testing.  Currently, the telescope is
in a "new focus" position that has given "the best image quality yet."  Analysis
of the out of focus images and the "in focus" images is in progress.
Preliminary analysis indicates there is improvement in the image.  All else
is quiet with all other spacecraft subsystems.
 
     Nothing new on the analysis of the 10 Faint Object Camera (FOC) images.
Efforts are underway to fix a FOC take data flag software error (the take
data flag now goes on if the Fine Guidance Sensors (FGS's) drop to gyro
control) and begin using the FOC to support focus activities along with the
Wide Field Planetary Camera (WFPC).  More FOC images will be taken later this
week.
 
     The only Pointing Control Subsystem (PCS) news concerns FGS dropouts and
the focus efforts.  Dropouts from both fine lock and coarse lock were occurring
with some regularity this weekend.  Analysis appears to show a good correlation
between the frequency of the FGS dropouts and mirror motion.  When the focus
was at its worst it was difficult to maintain coarse track, as the focus
improved coarse track became possible but not fine lock.  Further improvement
in the focus brought regular acquisition in fine lock.
 
     The focusing effort was the only major HST activity for the past three
days -- both in onboard activities and long range planning.  Beginning on
June 21 the mirror was moved to a number of focus positions, ranging from +12
waves to -12 waves from the June 20 focus position, with no tilting or
decentering.  After each movement wavefront sensor (WFS) and WFPC images were
taken.  The primary purpose of this focus series was to provide diagnostic data
on the HST/WFPC pupil function.  As with earlier focus runs the WFS data has
been plagued with data quality problems:  WFS1 data has been quite reliable,
WFS2 data has been, in general, quite poor, and WFS3 data has been of mixed
quality.  All WFPC images have been useful.  It appears that in the process
the Optical Telescope Assembly (OTA) team identified a new "better" focus and
the secondary was positioned at this new point.  It appears that all the mirror
motion, possibly with the exception of the last one, has been in focus and not
tilt or decentering.  Quantitative analysis of all the images is in progress.
There is a major effort to bring the FOC on line to support future focus
efforts, this will allow them separation of the  Scientific Instrument (SI)
focus/aberration problems from those of the OTA.  Beginning on June 28 a
switch to the star epsilon Sco will occur.  This star has the advantage of
not disappearing in a few days (as iota Car will) and will allow a return
(after this first focus effort) any time before early October and do
desorption focus runs.  Unfortunately, switching stars requires that steps
2 and 3 of the Bootstrap procedure be redone, adding an extra 48 hours.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |     Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___  Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /| M/S 301-355        |
 |_____|/  |_|/       |_____|/  Pasadena, CA 91109 |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.top
Date: 23 Jun 90 05:58:41 GMT

	WASHINGTON (UPI) -- NASA released the second image of the heavens
captured by the Hubble Space Telescope since the observatory was placed
into orbit, a picture of ancient stars snapped with the telescope's most
powerful camera.
	``After waiting all these years, it is a very exciting time. We are
now ready to start our observations with a tool more powerful than ever
before,'' said Robin Jakobsen of the European Space Agency, which built
the camera.
	The Faint Object Camera, one of six instruments aboard the $1.5
billion telescope, took the 10-minute exposure June 17 as an engineering
test of the camera and not to yield any new scientific discoveries.
	The black-and-white picture released Friday is of two stars in a
star cluster called NGC 188, which was selected because the positions
and brightness of the stars are well known, officials said.
	The cluster is about 5,000 light years from Earth and is about 12
billion years old, making it the oldest known cluster of its kind. A
light year is the distance light travels in a year at 186,000 miles per
second, about 5.8 trillion miles.
	The image shows the telescope's focus has improved significantly
since the telescope snapped its first picture May 20 with the
observatory's other camera, the Wide Field Planetary Camera.
	The new picture is about twice as sharp as the ``first light''
picture, which was clearer than scientists had anticipated.
	``It shows that we made progress in focusing the telescope between
when the first light photographs were taken and this was taken,'' said
NASA astronomer Steve Maran. ``But it also shows we're a long way from
the perfection Hubble was made to attain.''
	Once engineers finish focusing the telescope, the images should be
about 3 1/2 times sharper, he said.
	Earlier this week engineers hit a snag in their attempts to
continue focusing the telescope and analysts were trying to determine
what caused the problem. Officials, however, were optimistic they would
overcome it.
	NASA has battled one problem after another since the telescope was
placed into orbit by the crew of the space shuttle Discovery.
	Most of the problems have been resolved but engineers are rewriting
some of the telescope's computer programs to compensate for two small
vibrations, including one that occurs whenever the telescope passes into
or out of sunlight.
	``I'm pleased at (the picture) but like everybody else I'm
concerned that things are taking us as long as they are,'' Maran said.
``We have a lot of people and a lot of interest riding on this.''
	NASA released the new image with a picture of the same stars taken
by the Nordic Optical Telescope in the Canary Islands to show the
Earth-based image was much blurrier because it was taken through Earth's
obscuring atmosphere.
	From its perch 381 miles above Earth, the Hubble telescope is
expected to revolutionize astronomy by studying the universe in greater
detail than ever before for 15 years, possibly answering fundamental
questions about the cosmos.
	``I'm excited for many reasons. To me its the conclusion of a
15-year road and the beginning of another 15-year road,'' said F. Duccio
Machetto, lead scientist for the camera. ``It's a demonstration that
we're on the right track.''
	The camera can intensify starlight 100,000 times, the same as
increasing the light of a candle flame to the brightness of the noon
sun.

                    Hubble Space Telescope Update
                          June 25, 1990
 
     The Hubble Space Telescope, after a shaky two months in orbit,
has produced its second set of test pictures.  The sharp images,
taken by the Faint Object Camera, show that controllers at
Goddard Space Flight Center in Greenbelt have significantly
improved the focus of the telescope's mirror since the 'first
light' pictures from its other imaging system, the Wide Field and
Planetary Camera, were produced May 20.
 
     The new, sharper, pictures show two stars in
a cluster known as NGC 188, that is about 5,000 light years away,
and that the best ground-based images show only two fuzzy blurs.
 
     The telescope still has several weeks to go in its
complicated focusing process and that although things are
improving, they are still a long way from being operational.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |     Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___  Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /| M/S 301-355        |
 |_____|/  |_|/       |_____|/  Pasadena, CA 91109 |

    To get a bit of prespective:
    
    Can anyone tell me how long does it take to shake down a modern
    Earth bound telescope ?
    
    Thanks in advance,
    
    Chris

Someone asked this recently on the USENET.  The answer (and I don't know
the validity of it) was around 1 year for the modern scopes that are being
produced (especially the ones with active optics).

From what I've been able to understand of the status reports, the stuff they
are doing is typical of any highly precise telescope - and they have the
"advantage" of not having the environmental restrictions of clear skies at
night.

When the Keck observatory has first light, let's see how many people will
be climbing all over the astronomers for pictures.  I'd be surprised if the
event even manages a mention in the newspapers.


- dave

[p.s. People who have *real* knowledge of this topic are more than welcome
 to knock this gibberish down. :-)  ]

    In addition, they have to compensate for slight shrinkage and other
    changes in the carbon fiber support structure for the secondary mirror
    as it outgasses and adjusts to microgravity conditions. The net effect is
    apparently unknown (which may point out a difference between HST and
    KH-12 internals) so lots of adjustment capability was designed in (sort
    of like VMS' sysgen parameters :-) )
    
    gary

HUBBLE SPACE TELESCOPE ADVISORY - June 26, 1990
 
     In assessing the Hubble Space Telescope's optical 
performance, the orbital verification team conducted a series of 
focus tests, which involved moving the secondary mirror to a 
number of positions.  Wide Field Planetary Camera images were 
taken at each position to assess how the image quality changes 
with secondary mirror motion.
 
     The anticipated image quality was not achieved.  Computer 
models of the images indicate the source of this lesser quality 
image may be what is called "spherical aberration."  A spherical 
aberration occurs when all the light from a mirror does not focus 
precisely at the same point.
 
     NASA managers are now assessing the cause, studying how to 
compensate and determining its science implications.
 
     A news briefing will be held at the Goddard Space Flight 
Center, Greenbelt, Md., tomorrow afternoon, at approximately 
3-4 p.m. EDT, following a planned science review.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |     Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___  Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /| M/S 301-355        |
 |_____|/  |_|/       |_____|/  Pasadena, CA 91109 |

    On the Radio this morning (In the U.K.) they said a maint. mission
    is required to fix the focusing problem.
    
    The first shuttle was scheduled for 1993 this may now have to be
    brought forward..
    
    
    Chris

    Re .-1:
    
    I heard something similar - like the "1.5 billion dollar
    telescope can't be focused until a repair mission is sent".
    
    Last I heard the focusing was not perfect, but pictures
    were still better than 3x what they could obtain using
    ground-based telescopes.
    
    Is this another case of the press jumping to conclusions?

    
    re: .67
    
    Well judging from the media's glorious past I'd have to say yes.
    
    /prc

    As usuall the media has made a mess out of things.  Yesterday,
    listening to CNN, they gave the impression that the $1Billion system
    had been found to be useless due to an error in it design, and that
    until a mission in 1993 it would not do anything.  According to them it
    cannot take a picture because the mirrors are out of focus;  NASA has
    messed up big time.  Their continual emphasis on the negative is really
    awfull.  Most people probably think that we just waisted $1Billion.
    Even Dave Barry made fun of NASA and the Hubble in last Sunday's paper.
    
    I guess journalist are second to only politicians when it comes to
    scum and stupidity!

[I thought that this was well-timed...  Other news as soon as I can get it. -dg]

From: [email protected] (Greg S. Hennessy)
Newsgroups: sci.astro,sci.space
Subject: What Spherical Aberration is
Date: 28 Jun 90 02:52:00 GMT
Organization: University of Virginia


Once more with feeling.

Since HST is apparently suffering from Spherical aberration, and
seeing how lousy the news reports were tonight, I thought I would give
the readers a brief summary of what spherical aberration is.

An "aberration" is a manner in which an image is degraded. There are
five principal aberrations: coma, spherical aberration, astigmatism,
chromatic aberration, and field curvature. It is impossible to get rid
of all of these at the same time, but you try to get them to
acceptable limits. To explain spherical aberration, I will make use of
the principle of reprocitity, which means that instead of light coming
into the telescope, I will use light going out of a telescope.

If you have a point source of light, and want to have a curved surface
to change the radially expanding rays into plane parallel rays, it is
easy to calculate that the proper shape for the mirror is a parabola.
However, if the mirror is a spherical mirror, the rays are not
parallel after being reflected. This means that parallel rays coming
into the mirror (as from a distant star) are not reflected into a
point, but into a fuzzy area. Parabolas do not suffer spherical
aberration. Spherical mirrors do. (Actually all non spherical mirrors
suffer from spherical aberration. Don't ask why it is named such.) 

There are many different designs of telescopes. One of the most common
is the Cassegrain, which has a paraboloidal primary, and a hyperbolic
secondary (the shapes are generally conic sections). If you look at a
picture of HST you may think that its optics are Cassegrain, but the
optics are actually a Ritchey-Chretien design. The advantage of the
Ritchey-Chretien is that the field of view is much larger than a
Cassegrain, which is important for HST since it has to have several
instruments collecting light at the same time. The Ritchey-Chretien
has a more relaxed primary than a parabola (i.e. closer to a sphere)
by a few wavelengths. This introduces spherical aberration, but cuts
down on coma by quite a bit. The secondary mirror is modified such
that it will eliminate the spherical aberration from the primary. A RC
telescope does suffer from astigmatism and field curvature. For earth
based instruments, these effects are much reduced if you are on axis,
and for mechanical reasons most instruments are mounted on axis. The
HST has the WF/PC on axis, while all the other instruments are off
axis. Each of these instruments are designed to compensate for
astigmatism and field curvature. 

So far I have been factual. I will now begin speculation.

It seems that the secondary mirror of HST was not designed in the
proper shape. Simply moving it around (as they can do) will not solve
the problem. Replacing the primary mirror will not fix the problem,
since it is not the cause. Replacing the secondary should fix it,
except this is impossible. The instruments were designed to be
replaced, but the secondary was not, and they won't bring HST back to
earth. The people who built the mirrors and assembled it apparently
made the mirrors to the specs they were given, but it appears the
specs were incorrect. New instruments CAN be designed to correct for
the spherical aberration, but it will be a few years before this can
happen. The instruments were planned to be replaced anyway in a few
years, this gives us more reason to. It is presently unclear how much
science will be lost, although I heard a quote that the Wide Field
camera is useless for scientific work.

I hope this helps.


--
-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      [email protected]  
 UUCP:		...!uunet!virginia!gsh7w

From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.science,clari.news.gov.usa,clari.tw.space,clari.tw.aerospace,clari.news.urgent
Date: 27 Jun 90 23:14:14 GMT

	GREENBELT, Md. (UPI) -- One or both of the $1.5 billion Hubble Space
Telescope's critical mirrors appear to be incorrectly shaped, producing
blurry images and crippling the glitch-plagued observatory's ability to
probe the universe, officials said Wednesday.
	It is the most serious problem to affect the showcase satellite
since its launch from the shuttle Discovery on April 25. And while NASA
hopes the trouble ultimately can be fixed during a space shuttle repair
mission, long-awaited photographs from the telescope's primary camera
will be virtually eliminated until such a flight gets off the ground.
	Hubble project scientist Edward Weiler said the telescope suffered
from ``bad myopia'' -- near-sightedness -- and that most pictures from the
instrument would be little better than those taken from ground-based
telescopes.
	As a result, Hubble's ability to probe the cosmos will be sharply
reduced until a second-generation camera now being developed can be
installed over the next few years that is capable of compensating for
the ``spherical aberration'' that is crippling its performance.
	A shuttle flight to service the big telescope is on the books for
April 1991, but it was not immediately clear if a replacement camera can
be ready for flight that soon.
	``HST was and is a difficult challenge,'' Weiler said. ``It would
be dishonest for me to say the mood of the scientists is very happy
right now. We're all very frustrated. But we should be able to fix it.''
	Spherical aberration results when a mirror's shape is such that
light striking different areas of the reflecting surface is brought to a
focus at different points. The result is an out-of-focus image and
officials were at a loss to explain how such a defect made it into a
$1.5 billion telescope.
	Hubble's wide-field planetary camera, which was to have accounted
for 40 percent of the telescope's early science operations, is virtually
useless with such aberration, preventing the instrument from taking
spectacular, long-awaited photographs of the heavens from above Earth's
hazy atmosphere.
	Lennard Fisk, associate administrator for space science and
applications, said a special review board, chaired by Jet Propulsion
Laboratory director Lew Allen, will be formed to investigate what caused
the problem in the first place.
	The problem came to light after engineers at the Goddard Space
Flight Center finished a series of tests to focus the high-tech
telescope's optical system by making tiny changes in the position of a
critical relay mirror mounted in front of the instrument's 94.5-inch
primary mirror.
	After each tiny movement, a sensitive camera took a photograph to
assess how the image quality had changed, a direct indication of the
quality of the telescope's focus. It soon became apparent Hubble had a
major problem.
	``We got a very clear and distinct characteristic, a textbook
characteristic, of an optical system that had a significant amount of
spherical aberration,'' said deputy project manager Jean Olivier. ``We
are in the process of evaluating the ramifications of this.''
	The Hubble Space Telescope, the most expensive satellite ever
built, is a cassegrain design, that is, light enters its tube, bounces
off a primary mirror and then up to a smaller, secondary mirror mounted
near the opening of the tube.
	From there, the light is reflected back through a hole in the
primary mirror and brought to a focus. The concentrated light then is
fed into instruments mounted around the ``focal plane.''
	Olivier said the aberration seen in Hubble's optical system is so
perfect it likely was caused when the telescope's mirrors were being
machined years ago by what is now Hughes Danbury Optical Systems Corp.
of Danbury, Conn.
	``What we suspect is that in the ... techniques used to measure the
figure of the mirror and polish it and hold it steady while you're doing
that ... somewhere in this chain, there was a mistake or error made that
resulted in the mirror being very precisely made but ultimately to the
wrong figure,'' he said.
	Specifications called for the telescope to focus 70 percent of a
star's light into a certain area. As it stands, only 20 percent to 30
percent of the energy falls in the specified area.
	Ever since Hubble's launch from Discovery, engineers have been
struggling to resolve a variety of problems that have slowed the
telescope's activation.
	Unexpected wobbling motions, trouble with data relay antennas and
problems with the telescope's ultra-precise tracking system have caused
repeated delays for the observatory's checkout, but the mirror problem
is the most serious threat yet to the costly instrument.
	Second-generation instruments currently under construction will be
modified to compensate for the poor focus, but such instruments are not
scheduled for launch until 1993 or 1994.
	Weiler said engineers at the Jet Propulsion Laboratory have been
asked to look into speeding up development of the follow-on planetary
camera. In the meantime, the telescope will be used to study ultraviolet
emissions and other phenomena that are not affected by the focus
problem.

From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.top
Date: 28 Jun 90 04:33:21 GMT

	GREENBELT, Md. (UPI) -- A special camera can be modified to correct
the crippling defects in the Hubble Space Telescope's focusing system,
but it was not clear whether the camera can be ready for a scheduled
shuttle service flight to the orbiting instrument in April 1991.
	Because of flaws in Hubble's mirrors, called ``spherical
aberration,'' the $1.5 billion telescope cannot be sharply focused,
deferring its science output by about 40 percent until such a camera can
be installed.
	A special panel is being formed to investigate the problem, but at
a news conference Wednesday, NASA officials were at a loss to explain
how such a basic optical defect made it into a $1.5 billion telescope
considered by many to be the showcase payload of the shuttle era.
	As it is, Hubble's performance in the visible-light portion of the
spectrum will be little better than that of much cheaper ground-based
telescopes until the problem can be corrected during a space shuttle
repair mission.
	``HST was and is a difficult challenge,'' Hubble project scientist
Edward Weiler said. ``It would be dishonest for me to say the mood of
the scientists is very happy right now. We're all very frustrated. But
we should be able to fix it. I think we're all commited to working on it
and doing it right.''
	Spherical aberration, one of several problems that can affect an
optical system, results when a mirror is shaped so that light striking
different areas of the reflecting surface is brought to a focus at
different points, depending on how far from the center of the mirror the
light struck.
	The Hubble Space Telescope was built to study the universe from
high above Earth's obscuring atmosphere. For years NASA has hailed the
robot observatory as the most revolutionary step forward in astronomy
since Galileo first trained his spyglass on the heavens 400 years ago.
	But ever since its launch from the shuttle Discovery on April 25 --
seven years behind schedule and $1 billion over budget -- Hubble has been
plagued by a seemingly endless series of technical glitches that have
slowed orbital checkout and raised questions about the instrument's
ability to operate around the clock for its planned 15-year lifetime.
	The observatory is equipped with five primary instruments,
including two visible-light cameras.
	The wide-field planetary camera, which was to have accounted for 40
percent of the telescope's early science operations, is virtually
useless with such spherical aberration. The performance of the
European-built faint-object camera also will be hurt.
	Weiler said a second-generation, wide-field planetary camera can be
easily modified to correct the telescope's problem. But such an
instrument may not be ready for launch until 1993 or 1994. ``We can take
that (aberration) out, correct it, just like your glasses can correct
myopia,'' he said.
	A shuttle flight to service the big telescope is on the books for
April 1991, but it was not immediately clear if a replacement camera can
be ready for flight that soon.
	In the meantime, Hubble's observation schedule will be revised to
devote more time to other on-board instruments that do not require the
ultra-sharp focus of the telescope's two visible-light cameras.
	Deputy project manager Jean Olivier said the aberration seen in
Hubble's optical system is too uniform to have been caused by
Discovery's ground-shaking launch or by temperature effects in the cold,
weightless environment of space.
	The flaw, he said, may have been ground into the mirror system
during its manufacture by what is now Hughes Danbury Optical Systems
Corp. of Danbury, Conn.
	``What we suspect is that in the ... techniques used to measure the
figure of the mirror and polish it and hold it steady while you're doing
that ... somewhere in this chain, there was a mistake or error made that
resulted in the mirror being very precisely made but ultimately to the
wrong figure,'' he said.
	The problem came to light after engineers at the Goddard Space
Flight Center finished tests to focus the high-tech telescope's optical
system by making tiny changes in the position of a critical relay mirror
mounted in front of the instrument's 94.5-inch primary mirror.
	After each tiny movement, a sensitive camera took a photograph to
assess how the image quality had changed, a direct indication of the
quality of the telescope's focus. It soon became apparent Hubble had a
major problem.
	``We got a very clear and distinct characteristic, a textbook
characteristic, of an optical system that had a significant amount of
spherical aberration,'' Olivier said. ``We are in the process of
evaluating the ramifications of this.''
	The Hubble Space Telescope, the most expensive satellite ever
built, is a cassegrain design, that is, light enters its tube, bounces
off a primary mirror and then up to a smaller, secondary mirror mounted
near the opening of the tube.
	From there, the light is reflected back through a hole in the
primary mirror and brought to a focus. The concentrated light then is
fed into instruments mounted just behind the ``focal plane.''
	Specifications called for the telescope to focus 70 percent of a
star's light into a certain area. As it stands, only 20 percent to 30
percent of the energy falls in the specified area.

    While listening to the Bad News the other evening, I heard an
    interesting comment.  The commentator said that NASA had thought of
    testing the focus of the system on the ground, but evaluated it as 'too
    expensive' and therefore did not check the integrated unit.  I think
    the irony of this, assuming the report was accurate, is the question of
    how much is it going to cost now that it's where we can't easily get to
    it.   It sounds like they're going to slap in a BandAid (tm) fix to get
    it working in short order (~ 3 years?).  I can hardly wait.... maybe my 
    children's children can see the first maximized resolution photo's in the 
    next century :'(.  I realize that a lot of the other data collection can 
    still be done in that time, but this is still a BIG disappointment.
                                          

    For the LONG TERM would it be better to just bring the telescope back 
    after a few more months in space and fix the obvious engineering and 
    optical problems then schedule another launch with the repaired 
    unit?  I wonder if this option will be one of the alternatives NASA 
    will consider?
    
    Will the 'band-aid' approach provide the quality expected of this 
    instrument?
    
    Would like to hear your suggestions on the possible alternatives.
    
    John 

    I just watrched the replay of the press conference where NASA announced
    the HST problems, and as usual the press have distorted the image far
    more than any mirror problems might.
    
    HST has not met one of its primary design parameters, i.e. that 70% or
    more of the energy from a distant object should be focussed within 0.2
    arc seconds. They are currently able to achieve about 20% which is
    similar to the best ground based telescopes for visible light. It is
    still far better than anything previously achieved for UV in either
    space or ground based telescopes.
    
    The energy distribution matches that of a 'text book example' of
    spherical abberation.
    
    To have tested all up system focus on the ground would have required a
    precision blank at a cost of $100-200 million (an increase in
    spacecraft cost of approx 10%).
    
    The most impacted instruments are the Wide Field/Planetary Camera
    (WF/PC) and Faint Object Camera. By using longer exposures and computer
    deconvolution WF/PC will be useful for some observations, but in many
    cases it doesn't make sense to use HST when ground based systems can do
    as well. Observing very faint images does not lend itself to computer
    processing as it tend to decrease the signal/noise ratio of the image.
    
    Spectrographic observations will not be seriously impacted except in
    those cases where high spatial resolution is needed, e.g. examining
    single objects in a crowded region of the sky. The astrometry
    experiments use the fine guidance sensors and are not affected.
    
    Over the next few weeks, WF/PC will be used to test the optics to
    verify the nature of the problem. In addition, a review board has been
    convened to determine the cause of the problem.
    
    WF/PC 2 is currently being built at JPL for the previously scheduled
    HST service flight in 1993. If the problem is indeed sperical
    abberation, the optics in WF/PC 2 and other new instruments can be
    built to compensate and provide the planned resolution. JPL are looking
    at having it ready earlier in which case the service flight may be
    moved forward. Faint object work will probably have to wait for the
    1995 service flight when  a new faint object instrument (NICMOS - I
    forget the acronym) is scheduled to be installed.
    
    Since the first few years of science are over subscribed, the worst
    possible outcome is that WF/PC will essentially be turned off or used
    for a smaller number of long duration exposures and the UV and
    astrometry folks will get more science time than they expected.
    Remember this is a 15 year program with planned shuttle servicing
    flights. The overall change as a result of the mirror problem is mostly
    a change in the scheduling of science activities, and fewer gee-whiz
    pictures for the press in the first few years.
    
    gary

    re .74 (returning HST to the ground)
    
    There are significant risks involved, and it thought that contamination
    of the mirrors would degrade UV performance significantly.
    
    If the problem is spherical abberation then it is systematic and can be
    corrected in instrument optics and provide the expected quality.
    
    gary

                           Hubble Space Telescope Update
                                 June 27, 1990
 
    Dr. Lew Allen, director at the Jet Propulsion Lab, has been selected to
lead the inquiry board to investigate the spherical aberrations in the
telescope's mirror system.
 
     The two mirrors on HST are components of the Optical Telescope
Assembly (OTA).  The optical system is a variation of a Cassegrain
design, called Ritchey-Chretien, which uses a folded design to enable
a long focal length of 189 feet to be packaged into a small telescope
length of 21 feet.  Both mirrors are hyperboloidal in shape, meaning they
have a slightly deeper curvature than a parabolic mirror.  This shape was
to correct all coma and spherical aberations everywhere in the field of
view.  The OTA takes incoming light down its tubular baffle.  The light
is reflected off the 94.5 inch primary mirror to the 12.2 inch secondary
mirror.  The light is then reflected by the secondary mirror through a
hole in the primary mirror to the focal plane. From the focal plane, the
Scientific Instruments (SI) and the Fine Guidance Sensors (FGS) recieve
the light.  The OTA was designed and built by the Perkin-Elmer Corporation.
 
     The telecope was designed such that 90% of the equipment and
instrumentation has a backup or identical unit. Components on the telecope
which were critcial subsystems and might possibly degrade over time were
packaged into what are called Oribital Replaceable Units (ORU), which could
be easily replaced in orbit in one piece.  There are 70 ORUs on HST ranging
from small fuse plugs to the telephone-booth size FOC.  The telecope's two
mirrors are not in an ORU package.
 
     Very little has happened in orbit during the past 24 hours, but the
next 24 hours should see an OTA test, Faint Object Spectrograph (FOS) High
Voltage (HV) turned on and tests of the High Speed Photometer (HSP)
Photomultiplier Tube (PMT) detector.
 
     On the Pointing Control Subsystem (PCS) instabilities, it may be possible
to remove most of the disturbances seen in the HST pointing to reduce the
amplitude of the disturbance by at least a factor of 10 and maybe by as much
as a factor of 100, and do this ahead of schedule (late July instead of early
August). The Fixed Head Star Tracker (FHST) produced two large updates
yesterday, these precipitated a few failed acquisitions.  The Fine Guidance
Sensor (FGS) S-Curve calibration is in progress.
 
     The Faint Object Camera (FOC) is in hold.  FOC diagnostic images in
support of focus efforts may start on July 1.
 
     The Goddard High Resolution Spectrograph (GHRS) is in hold.  The HV
electronic dark count test apparently went well, the data is being analyzed
at this time.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

                          Hubble Space Telescope Update
                                June 28, 1990
 
     At least one of the two mirrors in the Hubble Space Telescope (HST) was
built in the wrong shape and will not work properly. The flaw most seriously
affects the Wide Field and Planetary Camera (WFPC) and the Faint Object Camera
(FOC) which use visible light but doesn't affect as heavily four other
instruments which do not depend heavily on crisp, clean visible images. The
WFPC, that was to do 40 percent of the scientific work, will not be usable and
the FOC will not work as hoped.
 
     Even with a bad mirror the HST will still be usable with the instruments
that use ultraviolet or infrared light. Infrared and ultraviolet astronomy will
get priority over visible light astronomy and the HST should still be able to
detect distant quasars, as well as study closer objects like Jupiter's Great
Red Spot.
 
    The mirrors were not tested together before launch because that would have
cost hundreds of millions of dollars. Even after HST was assembled the system
was so delicately balanced it could not be calibrated and tested under the
influence of Earth's gravity.
 
     Ground controllers may be able to compensate for some of the problems,
but a permanent correction will have to wait two or three years for astronauts
to visit the craft and replace some of the parts.  Corrective optics on a
second generation of instruments currently under construction may compensate
for the spherical aberration, and could be available for launch in 1993, 1996
and 1997.
 
     The problem with the mirrors is suspected to have happened during the
time the mirrors were measured and polished.  The mirrors were ground to
shape in Perkin Elmer's optics fabrication facility, and once the mirrors
were close to their final hyperboloidal shape, they were transferred to the
Perkin Elmer's computer controlled polishing facility.  They were measured
and polished very carefully; the largest deviation from perfection anywhere
on the surface of the mirrors is less than half a millionth of an inch.
However, the process was probably done to a wrong figure somewhere during
this time.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Someone asked if the "band-aid" approach would still retain the quality
that Hubble promised.

Speculating (without knowing anything about the numbers involved,) I would
have to say yes, it will.  Spherical aberration is just one of the side
effects of a particular optical design - and the Hubble has other aberrations
that are dealt with in the scientific instruments (e.g., those instruments
that are slightly off-axis (everything but the WF/PC I think) have to deal
field curvature (astigmatism).  Adding optics to compensate for the spherical
aberration seem rather straightforward -- the HST is just a bit difficult to
service).  This just ends up being an unexpected change in the instrument
design.  On the plus side (as he struggles to find one), the data that they
have should allow for very precise correction optics to be designed.


There's been a lot of grumbling about a lack of testing (as if *none* was
done).  I believe the cost of the tests have already been stated ($100 million+)
and even after the fact, I think they probably made the right choice with the
budget they had.  Cost aside, the tests may not have shown any problems.  One
theory kicking around various circles is that the problem is systematic and
induced by microgravity.  If this proves out to be correct, then no amount
of testing on the ground would have found this (plus the added expense and
embarassment of the massively expensive test).

Finally, I'd like to restress that the promises of the Hubble Space Telescope
were made with a 15 year mission in mind.  The "keys to the universe" (or
whatever bit of hyperbole you wish to attach to this) were not scheduled to
be delivered 1 month or 1 year after it was launched - the key what we
will learn over the next 15 years - and that still has great promise.

As to the "waste of money" -- how many of you were whining when a $2 billion
intelligence satellite burned up in the atmosphere a few months ago?  Oh well,
I guess well-publicized tax dollars cost more.  My point is that it is a bit
premature to call this a waste of money when the problem apparently can be
fixed - just not tomorrow.

Perhaps some good will come of this.  HST's optical advantages have declined
over the years with active optics, and other ground-based improvements. Now
would be a good time to review its mission and perhaps skew it to those
programs that are best suited to HST: UV studies, astrometry, and those
observations requiring narrow angles.  Those who have invested umpteen years
designing their experiments are not likely to take this suggestion very
seriously, but the astronomical community should demand the best bang for
the buck.

- dave

From: [email protected]
Newsgroups: clari.tw.space,clari.news.gov.usa,clari.tw.telecom
Date: 28 Jun 90 17:41:05 GMT

	DANBURY, Conn. (UPI) -- Hughes Danbury Optical Systems Corp.
officials said Thursday the cause of the $1.5 billion Hubble Space
Telescope's troubles most likely lie in one of two massive mirrors it
built for the space-roving observatory.
	``We are in agreement (with NASA) that there is a spherical
aberration in the telescope system and that the most likely cause is one
of the two mirrors,'' said Thomas Arconti, spokesman for Hughes Danbury
Optical Systems.
	The 1,827-pound, 94.5-inch diameter primary mirror is made of
ultra-low-expansion titanium silicate glass coated with aluminum and
magnesium fluoride to enhance reflectivity. The special coating is just
4 millionths of an inch thick.
	The secondary mirror is 27.4 pounds and 12.2 inches diameter.
	Perkin-Elmer's Electro-Optics Technology division in Danbury built
the mirrors in 1980 and 1981. The division was purchased by Hughes
Aircraft in December 1989 and is now called Hughes Danbury Optical
Systems.
	The Hubble, which was launched April 25 with the space shuttle
Discovery, was designed to be the most powerful optical instrument ever
built for operation above Earth's obscuring atmosphere.
	The telescope, however, has failed to return the dazzling view of
the universe that was expected.
	``At this point we do not know what the cause (of the defect) could
have been,'' said Arconti.
	``We've assembled our own internal team of scientists and engineers
that will work very closely with the NASA review team,'' he said.
	The defect virtually eliminated the use of a key camera and halted
about half of all the telescope's planned scientific work until a
shuttle crew can go back to the telescope and make repairs in 1993, NASA
officials said.
	``Where we suspect the problem happened is in the technique used to
measure and polish the mirrors,'' said Jean Olivier, deputy manager for
the telescope at Marshall Space Flight Center on Wednesday.
	``It's absolutely much too early to speculate what the cause of the
problem is,'' Arconti countered.
	``The testing was very intricate. It involved very sophisticated
computer polishing,'' said Arconti.
	He said the glitch has disappointed company officials.
	``Everybody thought that everything would have been working
properly and it was very much a surprise for us to find out that there
was this aberration,'' said Arconti. 
--
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From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.top
Date: 28 Jun 90 18:23:39 GMT

	CAPE CANAVERAL, Fla. (UPI) -- Engineers huddled Thursday to assess
the impact of the $1.5 billion Hubble Space Telescope's astonishing
inability to sharply focus starlight, a crippling disorder that sent
shock waves through the science community.
	James Westphal, the scientist in charge of the telescope's
now-useless $40 million Wide Field/Planetary Camera, said no one
anticipated problems with Hubble's supposedly near-perfect mirrors. But
that is precisely what appears to be the case.
	``We don't know exactly where the problem is,'' he said by
telephone from the Goddard Space Flight Center in Greenbelt, Md. ``We've
made some exquisite mirrors, but apparently one or both of them is the
wrong shape. It is a thing that none of us dreamed would happen. It's
tough.''
	While clearly disspirited, he said Hubble, the most expensive
satellite ever built, ultimately will live up to its billing as one of
the world's foremost observatories once modified instruments are
installed during a space shuttle repair mission two or three years from
now.
	``It's a major setback. It's not a disaster,'' he said. ``It can
turn into a disaster, clearly, if somebody makes a decision to kill the
whole program, and such a decision is not an impossible thing to imagine
could happen. That's why we're very anxious to get people to understand
how it really is.''
	Hubble deputy project manager Jean Olivier said Wednesday one or
both of Hubble's critical light-gathering mirrors appears to have been
ground into the wrong shape when they were manufactured years ago,
causing a phenomenon known as ``spherical aberration.''
	In optical systems suffering from spherical aberration, light
falling on different parts of a telescope's primary mirror is brought to
a focus in different places, making a sharp focus impossible. Hubble's
mirrors were ground and polished by what is now Hughes Danbury Optical
Systems Inc. of Danbury, Conn.
	``How could we possibly have had this problem? The answer is, it's
a low-technology problem,'' Westphal said. ``Almost all of ST's problems
through history have been low-technology problems.
	``And now somebody dropped a decimal point when they typed a
manufacturing record ... or somebody didn't do a test right, or didn't
have the set up exactly right, there's a long list of candidates. It'll
probably be a month or two before we know.''
	Engineers are using Westphal's grand piano-sized camera, known by
its acronym WFPC -- pronounced ``Whiff-Pick'' -- to map the surface of
Hubble's primary mirror to fully characterize the nature of the
aberration.
	In so doing, second-generation instruments under development can be
modified to compensate for the effect in much the same fashion that
glasses can correct vision problems on Earth.
	But WFPC-2, an upgraded version of Westphal's original, will not be
ready for installation by spacewalking shuttle astronauts for up to
three years, delaying Hubble's long-awaited ultra-sharp photos of stars
and galaxies at the edge of the universe.
	Such photos from WFPC alone were to have made up some 40 percent of
Hubble's observations over the first three years.
	But Westphal, a widely respected astronomer at the California
Institute of Technology, predicted Hubble's trouble will be corrected in
time and most of the science observations originally planned will, in
fact, be carried out when all is said and done.
	The Hubble Space Telescope, launched from the shuttle Discovery
April 25, is equipped with five primary instruments: two cameras, two
light-splitting spectrographs and a high-tech light meter to precisely
study the brightness of stars and galaxies.
	To be useful, the two cameras require the telescope's 94.5-inch
primary mirror to bring starlight into a super-sharp focus. But
spectrographs do not require the same level of resolution, or clarity,
to produce useful results.
	Before the focusing problem developed, observing time on the space
telescope was heavily over-booked and roughly split between camera
targets and spectrographic studies.
	The observing schedule now likely will be revised to give the
spectrgraphs more time than originally planned until WFPC-2 can be
installed during a space shuttle repair mission.
	But there is no follow-on instrument currently being developed to
replace Hubble's European-built Faint Object Camera. With the
telescope's poor focus, the ``FOC'' can only produce pictures roughly
comparable to those taken by ground-based instruments.
	Still, the FOC can photograph ultraviolet light, which is not
possible at all from the ground, so useful research might still be done.

A couple of points occurred to me in connection with the HST aberration
problem.

Firstly, about the long lead-time to replace the instruments with versions
which can correct the aberration. Is the length of time due to the difficulty
of scheduling a Shuttle flight, or is it due to the difficulty of designing new
optics for the instruments?

If Shuttle scheduling is a problem, would it not have been sensible, given the
apparent difficulty of testing the telescope optics on the ground, to have
pencilled in a series of 'draft' servicing missions during the first few years,
just in case of problems of this nature? If these 'draft' missions turned out
not to be needed (as many of them probably wouldn't), they could then have been
cancelled or else used for other purposes. Could such flexible mission
timetables be supported by the Shuttle? If not, why not, given the nature of
the Shuttle?

Secondly, I would suggest that, even if the imaging instruments on the HST are
not much better than ground-based instruments, it would still be worth taking
some and publishing them, if only to convince funders that something was being
provided in return for the money. The fact that these pictures would have
limited scientific value might not be so bad, so long as the press could be
allowed to publish them. It might even be beneficial to future funding to give
away such pictures FREE to anybody wanting them, so as to help maintain a high
profile for the HST. And, in any case, surely these pictures will suffer from
less 'sky noise' than Earth-based pictures? Wouldn't this offer any scientific
advantages over pictures from Earth-based telescopes?


Dave Hazel

    
    
    	I may be wrong in this I cant remember, but I though the HST main
    mirroe shape could be distorted as it was controlled via pressure pads
    at its rear.
    
    	If this is the case why dont they just alter its shape to bring it
    back into focus.
    
    	On the point of not testing the main optics, whoever, built an
    optical system and never tested it.  How stupid can anyone be !
    
    Chris

    Re. -1:
    
    Why would the HST mirror need to be capable of being distorted?
    It is designed to operate in a microgravity environment, where there are
    no significant distorting forces (except perhaps thermal distortion).
    
    On the (by now repetitive) point about not testing the optics on
    the ground, I believe the cost of this has been underlined several
    times. $100 million is the same order of magnitude cost as most
    complete satellites. It has also been pointed out (either in this
    topic, or else in a similar one in the Astronomy conference), that
    the HST optics were designed for a microgravity environment, and
    would therefore not have functioned correctly under Earth's 1G
    environment. In other words, it was a case of the complete system being
    unTESTABLE, rather than unTESTED.
    
    However, this fact could rightly be used to argue that someone should
    have checked the specifications very thoroughly before figuring
    the mirror surface(s). Lack of testability of the result should
    have meant ultra-careful preparation of the specifications, and
    ultra-careful checking of them before implementing them. It is this
    apparent lack of care which needs to be addressed, not the lack
    of testing.
    
    (By the way, I say 'apparent', because it has been suggested somewhere
    that the distortion causing the aberration might have been caused
    by environmental factors. I think the suggestion was that the change
    from a 1G environment to a microgravity one might be the cause,
    in which case the problem might not have been predictable, and
    certainly wouldn't have been testable.)
    
    
    Dave Hazel

    The main mirror does rest on supports that will allow some controlled
    distortion of the mirror surface. At the press conference they
    mentioned that (if their initial analysis is correct) the required
    movements would be in the axis/direction where the mirror is stiffest
    and there may not be enough latitude to correct the problem, and I
    think it only applies if the problem is the main mirror.
    
    As for was it testable on earth, the scientists at the press conference
    claimed that it was testable, but it would have been very expensive and
    very difficult.
    
    gary

    	I'm surprised that nobody has commented about the [mis]use of the
    phrases about 'highly sophisticated computerized polishing' and
    resulting surfaces that got within .000001 nano-hair of [im]perfection.
    
    	How long is it going to take before they learn: GIGO !!
    
    	- Chris, sigh

From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.top
Date: 29 Jun 90 21:39:12 GMT

	WASHINGTON (UPI) -- Lawmakers blasted NASA Friday for failing to
detect crippling flaws in $1.5 billion Hubble Space Telescope before
launch, saying it casts doubt on NASA's ability to handle future
high-tech projects like the mission to Mars.
	``What does this mean for the rest of the things you want to do?
Are we going to keep ending up with techno turkeys?,'' said Sen. Barbara
Mikulski, D-Md., head of the Senate appropriations subcommittee that
funds NASA programs. ``I think this has seriously hurt the credibility
of NASA when they've had so much time and enough money to get it
right.''
	``You want to go more into space, you want to go to Mars. What
would we do if we had sent astronauts out and the life-support failed?
Say `Oh, no! We forgot to send you lunch -- and oxygen','' Mikulski said.
	Appearing at a Senate hearing, Lennard Fisk, NASA's associate
administrator for space science and applications, said he could neither
confirm nor deny reports that NASA decided against using top-secret
military testing equipment that may have detected debilitating errors in
the telescope's vital mirrors prior to launch.
	The New York Times quoted industry experts as saying the military
system, routinely used to test mirrors on spy satellites, probably would
have picked up the problem. The Wall Street Journal also quoted Robert
Brown, Hubble's chief scientist from 1983 to 1985, as saying
ground-based tests costing a few hundred thousand dollars ``could have
caught the problem.'' Brown said he did not know why NASA did not
perform such tests.
	Fisk once again refused to speculate on how one of the telescope's
two light-gathering mirrors ended up ground into the wrong shape. The
error -- which threw the mirror's curve off less than one-twentieth of
the width of a strand of human hair -- has prevented Hubble from bringing
starlight to a sharp focus and delayed, probably for several years under
the best circumstances, long-awaited pictures of stars at the edge of
the universe.
	``I am extremely concerned by the fact that after spending almost
$2 billion over a 12-year period, we only now find out that this type of
mistake could occur and NASA did not test the two mirrors in conjunction
with each other as they are normally used,'' Sen. Al Gore, D-Tenn., head
of the Senate Subcommittee on Science, Technology and Space.
	Fisk said such a trial was ``judged not to have a good cost-benefit
ratio.'' He offered no cost estimate of such testing, but said the
procedure would have been ``very elaborate'' because it must be
performed under weightless conditions.
	The mirrors were ground about 1980 by a contractor, now known as
Hughes Danbury Optical Systems Inc. of Danbury, Conn. Gore noted that
was a period in which NASA had slashed its quality control staff by 70
percent -- and a period in which the defective rocket booster that caused
the Jan. 28, 1986, explosion of the shuttle Challenger was produced and
the Atlantis and Columbia shuttles, which are now plagued by fuel leaks,
were designed.
	``Since the mistakes that were made in the Hubble were made at
roughly the same time as the mistakes leading to the Challenger tragedy
were made, is it possible that NASA's decision to eliminate 70 percent
of its quality control personnel was the common denominator in both
problems?,'' Gore asked.
	Fisk said he did not know what role quality assurance efforts
played in Hubble's problems, but said that issue would be among those
studied by a independent review committee investigating the mistake.
	Gore asked Fisk if, given the shuttle leaks and the problems with
Hubble, NASA is ready to undertake complex, long-lasting missions like
the moon-Mars initiative proposed by President Bush.
	``We know what we are doing,'' said Fisk, emphasizing management of
the space agency has changed radically since the early `80s.
	``Anytime you press technology as far as NASA is willing to press
it, occasionally you fall short. We don't deliberately fall short. We do
our very best not to fall short,'' he said.
	About 40 percent of the scientific projects NASA planned to conduct
during Hubble's first several years will probably be delayed due to the
faulty mirror.But NASA officials said they think Hubble will achieve at
least 90 percent of its scientific goals over its planned 15-year
lifetime once new instruments, equipped with lenses to compensate for
the mirror flaws, are installed by a shuttle mission in about three
years.
	Hubble project scientist Edward Weiler said Hughes Danbury,
formerly Perkin-Elmer Corp., won the contract to grind and polish
Hubble's mirrors by coming up with the best proposal to meet
requirements set by the space agency.
	``We didn't tell them what the prescription was,'' Weiler said.
``They determined what the prescription should be. But there are many
checkers in the system and somewhere the system failed. We don't know
whether it was software, we don't know whether it was hardware.
	``This all happened eight to 10 years ago and it's going to be a
real detective job for our independent team to go out and dig up the
facts,'' said Weiler, who expects a report from the panel in a couple
months.

From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military
Date: 29 Jun 90 21:30:51 GMT

	CAPE CANAVERAL, Fla. (UPI) -- Scientists expressed cautious optimism
Friday that despite a seriously flawed optical system, the Hubble Space
Telescope can still produce valuable data about the birth and fate of
the universe.
	In a special position paper written by members of the Hubble
Science Working Group and the space telescope users committee,
scientists agreed the $1.5 billion project ``has clearly suffered a
major setback due to telescope optics that are well below
specification.''
	Even so, they wrote, ``we are convinced that the long-term
prospects for completion of the science program are highly encouraging''
and that Hubble ``still has the potential to produce many key
discoveries in the near future.''
	The Hubble Space Telescope, the most expensive satellite ever
built, was launched from the shuttle Discovery April 25. Engineers
announced Wednesday that one of Hubble's supposedly near-perfect mirrors
was incorrectly shaped, preventing the telescope from bringing starlight
into sharp focus.
	The telescope's 94.5-inch primary mirror and a smaller relay mirror
were ground and polished by what is now Hughes Danbury Optical Systems
Inc. of Danbury, Conn.
	For some reason, the curvature of one of the mirrors is off by
about 2 microns, or about 4 percent the thickness of a human hair. The
result was spherical aberration, which causes light striking different
parts of the main mirror to come to a focus at more than one point.
	That causes blurry images and in Hubble's case, the best possible
focus is still seven times worse than called for in NASA's original
specifications for the optical system.
	Such aberration can be counteracted by putting special lenses into
cameras and other instruments to bring the light to a focus at one point
much like glasses can correct vision problems on Earth.
	The instruments aboard Hubble that are most affected by the
focusing problem are two high-tech cameras that were to have taken
long-awaited pictures of stars and galaxies at the edge of the universe.
Now, they are virtually useless, although good photos of especially
bright targets are still possible.
	A new Wide Field/Planetary Camera currently is under development
for installation in 1993 during a shuttle repair mission. The camera
will be modified to compensate for Hubble's optical defects.
	``It appears highly probable that the full imaging capabilities of
HST can be restored by straight-forward modifications to the
second-generation scientific instruments,'' the position paper said.
	``In comparison to the huge investment already made in HST, the
effort involved in correcting the optical aberrations is fairly small.''
	Hubble also is equipped with two light-splitting spectrographs and
a high-tech light meter that are not as seriously affected by focusing
problems.
	Until replacement cameras can be installed, Hubble will concentrate
on less-than-spectacular spectrographic studies that are impossible from
ground-based observatories.
	``HST right now has capabilities that vastly exceed ground-based
observatories,'' the position paper said. ``Most important are
spectroscopy, photometry and imaging at ultraviolet wavelengths, none of
which are possible at all from the ground.
	``High resolution visible-light imaging on bright objects will also
be possible, achieving to some degree the original fine details expected
in HST pictures.''
	Over the telescope's planned 15-year lifetime, officials said, at
least 90 percent of the observatory's scientific goals should be met
despite its optical defects.
--
This, and all articles in this news hierarchy are Copyright 1990 by the wire 
service or information provider and licenced to Clarinet Communications 
Corp.  for distribution.  Except for free samples, only paid subscribers 
may access these articles.  Any unauthorized access, reproduction or 
transmission is strictly prohibited.  We will reward the first provider of 
information that helps us stop violators of this copyright.  Send reports 
to [email protected].  

I received this through network mail this morning and thought it was
worthy of inclusion in this topic.  The forwarding pedigree has been
deleted.

Craig Geyer
-------------------------------------------------------------

Article         8092
From: [email protected] (Robert W. Spiker)
Newsgroups: sci.astro
Subject: What's wrong with HST
Date: 29 Jun 90 19:35:54 GMT
Sender: [email protected]
Organization: Department of Astronomy, Univ. of Virginia
 
The following was received as an email message from a friend at Penn
State; it has apparently gone through a bunch of places and different
people, who have all forwarded it.  I therefore place it upon the USENET:
 
The originator of this message is Dimitri Mihalas.
 
For those who want the condensed version, the software that
Perkin-Elmer used to polish the mirror was faulty.
 
Robert W. Spiker, UVa Dept. of Astronomy 
-------------------------------+ It is truly written that a man has five 
[email protected]| times as many fingers as ears, but only
  or @bessel.acc.virginia.edu  | twice as many ears as noses.
 
 
Message follows:
----------------------------------------------------------------------
in case you have not heard: from a reliable inside source i found out
that the problem with ST is that the SOFTWARE driving the polisher was
defective. the corrections for spherical aberration were put in with the
wrong sign. consequently the mirror is not corrected for sph. abb., but
has an added dose of it.
 
the error was not detected during testing because no test with collimated
light was ever done. (editorial remark: unthinkable!) apparently this was
a $30M economy measure in the face of the Challenger accident. likewise
none of the optics were ever tested in vacuum. the primary was and is
"perfect" relative to the specified curve; but alas the specification
was wrong. sigh.
 
>from my amateur astronomer days (does that include 1990?) i recall that
spherical aberration is EASY to detect with the foucault test, which is
done with a pinhole, not collimated light. it is hard to believe that
ANYONE could have made such a blunder..
 
the only reason that people know this much is that the same software
was used for AXAF. the errors there were so huge as to be immediately
noticeable, and when the software was corrected, the mirror was "perfect".
i don't know whether the information from axaf was available prior to
the launch of ST, but it seems that it had to be. in which case one
wonders why PE didn't issue a "hold everything!".
 
the future: no chance of bringing the whole telescope down for a refit.
best plan is to design compensating optics into the lightpath for future
instruments: relatively easy to do. but that will still take 3-5 years.
 
i suppose it's "win a few, lose a few..." but i personally think that
nasa, the government, and the people should stick it into PE and TURN
it hard until they agree to refund the cost of the mistake and of the repairs.
i'm sick of seeing defense and defense-related contractors get away
with bloody murder and just get fatter and fatter on the profits.
 
back to theory
dimitri
---------------------------------------------------------------------------

                      Hubble Space Telescope Update
                               June 29, 1990
 
     Since June 26 there has only a little activity in orbit but, as I am
sure most of you aware of by now, a lot of action on the ground. The Faint
Object Spectrograph (FOS) successfully turned on their Red Side High Voltage
(HV) over the past three days.  All went very well with no anomalies. The
High Speed Photometer (HSP) turned on their Photomultiplier Tube (PMT)
detector to check out the "rising counts" problem.  A quick look at the data
indicated that the problem had disappeared.  Unfortunately, analysis of the
data showed that this perception was due to differences in the way the two
tests were run and that the problem was still there, unchanged from before.
A move to the star eps Sco was accomplished and a new series of Bootstrap
proposals were started.  Things have not gone as well as people were hoping --
guide star acquisitions were failing (cause is under investigation).  Some
coarse alignment data has been obtained today but it was too early to tell if
enough data will be gathered to accomplish the alignment.  This Bootstrap runs
until 12:30 AM EDT on July 1.
 
     The news regarding the Pointing Control Subsystem (PCS) day/night
terminator instabilities looks very promising.  All indications are that the
efforts of engineers may be able to remove most of the disturbances;
reducing the ~200 milli-arc-second peak-to-peak oscillation by between a
factor of 10 to 100.  If this proves true then it would bring the HST
stability very close to or within pre-orbital specifications.  The delivery
schedule of the PCS fix is late July or early August.  As for the rest
of the PCS system, things are generally going well with the exception of the
most recent failed acquisitions.  Two of the failures have been traced to
"bit flips" in the Fine Guidance Sensors (FGS) caused by the South Atlantic
Anomaly (SAA), the remaining failures are under study.  All indications
are that the FGS S-Curve calibration went well for FGS 2 and 3 (no data on FGS
1) and that significant updates of the S-curve calibration will be implemented
for these two FGS's.
 
     Analysis of the run of focus images and Wavefront Sensor
(WFS) measurements made over the past week appear to show about 0.5 waves RMS
field independent spherical aberration at the Optical Telescope Assembly (OTA)
focal plane.  The cause is, at present, unknown.  From all indications the
spherical aberration is the only mirror problem -- in all other respects the
mirrors are perfect.  The current best guess explanation for the aberration
is that one of the mirrors has the wrong figure, a wrong conic constant.
At the present time it is unknown if the problem lies in the primary or the
secondary mirror.  Other items of interest: the paraxial to marginal focus is
4 cm, the circle of least confusion is ~1.5 arc second, if you were to
assume that the error is in the primary mirror and that the center of the
mirror is correct, then there will be ~2 micron error at the edge.  In terms
of real image quality we are talking about ~70% of the encircled energy in
~0.8 arc second radius and ~12% in 0.1 arcsec (spec was 70% in 0.1 arcsec
radius).  Also, the current focus produces significant differences in image
quality in the 3 FGS's (FGS 1 and 3 have ~0.7 arc-second images, whereas
FGS 2 has ~1.4 arc-second images).  The primary mirror has 24 force actuators
on it but they were designed to remove aberrations other than spherical and
are not likely to significantly improve the image.  Lots of testing to fully
characterize the image on and off axis are being planned for the next weeks.
With these data we should have a much better description of the focus of the
OTA.  Unfortunately, the bottom line appears to be that based on current
knowledge it is unlikely that there will be a significant improvement in
image quality in the OTA, even after the aberration is better characterized.
However, the aberration is fully and easily corrected in the next generation
of Scientific Instruments (SI). So, with the installation of Wide Field
Planetary Camera II (WFPC II) in 1993 (obviously an accelerated schedule
is under study) HST should regain its full imaging characteristics.
 
     HST is currently observing eps Sco for Bootstrap activities.  To do
this the telescope must be off nominal roll.  This is producing a cooling
of the SPA (Solar Power Array) Blanket.  As of this morning it was at -102 C
(~-80 C is normal and -100 C is the "red" limit).  The European Space Agency
(ESA) is studying the impact of the low temperature, if they find that it is
potentially harmful, then the spacecraft will be sent back to nominal roll
and the focus testing will come to a temporary halt.
 
     The Faint Object Camera (FOC) is in hold.  FOC diagnostic images in
support of focus efforts will start early on July 2.
 
     FOS is back in hold.  Blue side HV on went very well.  Dark count was as
expected (~1 x 10^-2), one possible new noisy diode was found but otherwise all
was as expected.
 
     WFPC is in full operate mode.  Next images are scheduled to start at
2 AM EDT on July 1.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Date: 2 Jul 90 20:42:13 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

HUBBLE BOARD OF INVESTIGATION NAMED
 
     Dr. Lennard A. Fisk, NASA Associate Administrator for Space 
Science and Applications today appointed a Hubble Space Telescope 
Optical Systems Board of Investigation to review, analyze and 
evaluate the facts and circumstances regarding the manufacture, 
development and testing of the Hubble Space Telescope Optical 
Telescope Assembly.
 
     The board will be chaired by Dr. Lew Allen, Director, Jet 
Propulsion Laboratory, Pasadena, Calif.  The other members of the 
board are:
 
      Charles P. Spoelhof
        (Retired) Vice President, Eastman Kodak Co.
        Pittsford, N.Y.
 
      George A. Rodney
        Associate Administrator for Safety and Mission Quality
        NASA Headquarters, Washington, D.C.
 
      John D. Mangus
        Head, Optics Branch, Space Technology Division
        NASA Goddard Space Flight Center, Greenbelt, Md.
 
      Dr. R. (Bob) Shannon
        Professor of Astronomy, Optical Sciences Center
        University of Arizona, Tucson
 
      Dr. Roger Angel
        Professor of Astronomy, Steward Observatory
        University of Arizona, Tucson
 
      Sarah Keegan, NASA Public Affairs Officer, and Gary Tesch,
NASA Deputy General Counsel, will support the board as public
affairs advisor and counsel, respectively.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

                         Hubble Space Telescope Update
                                 July 2, 1990
 
     The telescope has been slowly returned to nominal roll without major
thermal problems.  There has been a modest amount of activity in orbit, most
of it dealing with the Scientific Instruments (SI) rather than the focus.
Bootstrap activities continued as before with good Wavefront Sensor (WFS1)
measurements and bad WFS2 & 3 data.  The first attempt at using the Faint
Object Camera (FOC) to assist in characterizing the focus was not successful
-- possible pointing errors and a "take data" flag problem gave null results.
However, Wide Field Planetary Camera (WFPC) pictures were successfully taken.
All the SI related events went quite well with no anomalies or unexpected
events.  The Faint Object Spectograph (FOS) is in the process of turning on
their Blue Side High Voltage (HV) (successfully, so far), the FOC worked
well, despite not seeing stars, in its first focus support effort.  The
Goddard High Resolution Spectrograph (GHRS) was gathering HV dark count near
the South Atlantic Anomaly (SAA), The High Speed Photometer (HSP) was testing
the Photomultiplier Tube (PMT) detector, WFPC and the Fine Guidance Sensors
(FGS) continue to operate smoothly.
 
     Nothing new regarding the Pointing Control Subsystem (PCS) day/night
terminator instability fix.  There is high confidence that most of the
disturbance should be removed with the new flight software.  Expected time of
completion is early August (maybe late July).  The fix is expected to bring HST
stability to pre-launch expectations.  As for the rest of the PCS system, it is
clear that there are still problems with the Fixed Head Star Trackers (FHST)
but the problems do appear to be getting less frequent and understood quicker
than before.  The FHST's do appear to be the weakest link in the PCS, but there
is a growing understanding of how their operation can be made more reliable.
This problem is not expected to totally disappear until we get a few more
pointings under our belt (a month or two).  Flight operations has begun to load
the software to fix the "bit flips" in the FGS's caused by the SAA.  This
should remove the cause of some of the FGS acquisition failures.  A few FGS
failures are still ocurring for currently unknown reasons, investigations are
underway.
 
     In orbit activities are centered on setting up the new focus star,
epsilon Sco, for Wavefront Sensor (WFS) measurements.  In the past there have
been lot of problems getting good data off WFS2 & 3 (they do not see any
modulation of the signal in these two sensors).  The failure has been
attributed to a variety of causes, most recently an apparent inability to
properly center the star in the WFS aperture.  There have been a few more
pictures but nothing really new regarding the image quality.  Most of the
ground effort is directed at assessing the impact on existing science programs,
what can be done (if anything) to improve the existing focus, and once a focus
is established what should be done to better characterize the focus.
 
     FOC is taking images in support of focus efforts.  Their first attempt
was a failure, not because of anything within the FOC but because of a
possible pointing error and a command management problem that kept the
"take data" flag off during one of the FOC images (take data flag off =
closed shutter).
 
     FOS is in the process of turning on HV on the Blue side, so far (2 steps)
all is good.  Coarse Y-Base measurement went well.  Blue side HV finishes on
July 4.
 
     GHRS is doing a series of HV electronic dark count tests skirting the SAA.
All so far is going well.  Counts are lower than expected but the analysis
of the data has just begun.
 
     HSP is awaiting further testing of the PMT detector.  Ground hardware
tests seem to show that the cause of the problem is a minor "instability" in
one of the electronic components that should vanish with the application of
higher voltage.  The prediction is that no problems will exist when normal
operation voltage is reached.
 
     WFPC is in full operate mode.  Next images are scheduled for tomorrow.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military
Date: 2 Jul 90 21:30:30 GMT

	 WASHINGTON (UPI) -- NASA is capable of conducting complex missions
despite problems crippling the Hubble space telescope and space shuttle,
agency managers said Monday, adding high-tech imaging might salvage
exciting pictures from the telescope.
	Administrator Richard Truly insisted NASA is proceeding in a safe
and responsible manner, despite criticism about shuttle reliability and
agency management of major projects like the space telescope.
	``I believe we are doing precisely what the American public asked
us to do,'' Truly said, ``And that is when we run into a problem like
this, we're going to stop and assess it and fix it.''
	Some members of Congress have said the latest woes cast doubts on
NASA's ability to carry out large, highly complex projects like the
Space Station Freedom or a manned mission to Mars. Rep. Barbara
Mikulski, D-Md., head of the Senate appropriations subcommittee that
funds NASA programs, has asked: ``Are we going to keep ending up with
techno turkeys?''
	Truly told a news conference that although the proposed space
station is complex, he does not view it as any more difficult than the
space shuttle program. The NASA chief said he considers the shuttle
effort a great achievement, noting the 10 missions flown since the
Challenger disaster in 1986 have carried more payload into space than
launch efforts of all other nations combined.
	The shuttle program was recently grounded the discovery of hydrogen
fuel leaks in both the shuttle Columbia and Atlantis.
	``Everybody ought to remember that the space program is a program
of very high complexity,'' Truly said. ``It is very difficult and it's
risky. Therefore, you should assume if we fly for the next 10 years, 20
years, 100 years, we are going to continually run into difficulties.''
	``If we shy away just because the going is tough, future people
will never forgive us,'' he said.
	As for the $1.5 billion space telescope, NASA science chief Lennard
Fisk said the observatory's blurry vision eventually will be fixed by
installing modified cameras and that in the meantime, the big
observatory will produce ``world-class science'' by tracking non-visible
energy like ultraviolet light.
	``And there's growing optimism ... that we will be able to do image
reconstruction with the telescope in the visible (light) and produce
clear and exciting images of the universe,'' Fisk said.
	``I think you will discover Hubble space telescope in the next few
years ... produces exciting and very dramatic pictures of the universe
in addition to science essentially uninhibited by the problem with the
mirrors.''
	NASA officials said special teams were being formed to investigate
both the telescope and shuttle problems and develop corrective measures.
	Engineers announced last week that Hubble's supposedly near-perfect
mirrors somehow were ground to the wrong prescription, giving the most
expensive satellite ever built blurred vision and limiting its ability
to probe the secrets of the universe.
	It was a devastating setback to NASA and the showcase space
telescope project, touted for years as the most revolutionary step for
astronomy since Galileo first trained his spyglass on the heavens 400
years ago.
	But instead of beaming back super-sharp pictures of stars and
galaxies at the edge of the universe, Hubble will be limited primarily
to important but less-than-spectacular ultraviolet studies until new
cameras can be installed during a space shuttle repair mission in 1992
or 1993.
	Still, Fisk said computer processing of image data from Hubble may
yet yield useful photographs, despite the optical flaws.
	``We are stubborn. We are clever. We are going to make this work,''
Fisk said.
	Hubble suffers from spherical aberration, a defect that apparently
was built into its optical system some 10 years ago during construction
of its mirrors by what is now Hughes Danbury Optical Systems Inc. of
Danbury, Conn.
	During the computer-controlled grinding process, one of the mirrors
apparently ended up with a slightly different shape than called for by
the equations describing its parabolic curvature. The amount of error is
tiny: The mirror's curve is off by just one-fiftieth the thickness of a
human hair.
	In optical systems suffering spherical aberration, light striking
the outer portions of the primary mirror comes to a focus at a different
point than light bouncing off the inner region. The result is a blurry
image.
	But engineers say spherical aberration is relatively easy to fix
and that new cameras currently under development can be modified to
correct Hubble's trouble before they are installed by a space shuttle.
	``Some people say this is a sign we should not be doing complex
missions,'' Fisk said. ``The complex part of Hubble (like the guidance
sensors) is working just fine ... the simple part of the mission seems
to be where the process fell apart.''

RE:  .93

� The NASA chief said he considers the shuttle
� effort a great achievement, noting the 10 missions flown since the
� Challenger disaster in 1986 have carried more payload into space than
� launch efforts of all other nations combined.

How can this be?  I thought that the Soviets alone have over a hundred
launches a year.  Could he have meant "all other nations with the exception
of the Soviet Union"?

    The phrase he used in the press conference was "all other launches". He
    did not specify whose launches.
    
    gary

RE:  .93

� The NASA chief said he considers the shuttle
� effort a great achievement, noting the 10 missions flown since the
� Challenger disaster in 1986 have carried more payload into space than
� launch efforts of all other nations combined.

Do you think that they consider the shuttle as part of the payload?  I would
think that the weight of 10 shuttles would add up.

Fran

From: [email protected] (Eric Jaderlund)
Newsgroups: sci.astro,sci.space
Subject: HST / WF-PC: Update from those who know.
Date: 4 Jul 90 16:05:47 GMT
Organization: University of New Mexico, Albuquerque

Here is the poop, straight from the inside, geared mainly towards the
Wide Field / Planetary Camera.

*****************************************************************************
*****************************************************************************

	
	WIFFPICKERS    NEWS.703    ~16:00 3 JULY 90



                      PMA REPORT OF WFPC IDT

                         June 27 - July 2, 1990


			FROM AL BOGGESS:

Dear Colleague: 

     As you have no doubt heard from the press, the Hubble Space
Telescope has serious optical problems.  Since the media do not always
communicate the technical details with full accuracy, I would like to
inform the astronomical community about just what is wrong and what
its consequences are likely to be. 

     Tests in orbit have shown that the Optical Telescope Assembly has
about half a wave (r.m.s.) of spherical aberration.  If this error
were entirely due to the shape of the primary (which is only an
assumption) it would correspond to a mirror curvature that is too
shallow, with a total center-to-edge error of about two microns. 
Consequently the images will not achieve their anticipated quality. 
At a compromise focus, star images have cores whose full width at half
maximum is 65 to 70 milliarcsec. Although this core size is within
specification, it contains only about 15 percent of the light.  The
remainder of the energy is in a faint halo that spreads over an arc
second or more. 

     The HST Science Working Group and the newly-formed HST Users
Committee met on June 27/28 to consider the implications of this
situation, which is obviously a major setback.  The two groups
concluded that HST never-the-less has capabilities that far exceed and
complement those available on the ground and that its program should
go forward vigorously, emphasizing the unique and valuable science
that can be done with the telescope in its present condition. The
Working Group and Users Committee drafted a short report to NASA
summarizing their position, and that report is attached for your
information. 

     The cause and exact nature of the spherical aberration is still
being analyzed.  At present we do not know whether the error is in the
primary mirror or the secondary or distributed in some way between
them.  Although there are force actuators on the back of the primary,
they were designed to remove small amounts of coma and astigmatism. 
The correction needed now is a relatively large motion in a direction
in which the mirror blank is quite stiff, and the actuators are not
strong enough to do that job.  Consequently, the aberration does not
appear to be curable in orbit and the existing instruments will suffer
degraded performance - more or less, depending on the particular
instrument.  A quick assessment of these performances is contained in
the accompanying report.  On the other hand, we now believe that the
Advanced Scientific Instruments which are already planned and
scheduled for in-orbit installation can be fully compensated for the
aberration, so that two and a half or three years from now we can
expect the WF/PC-II to provide the sharp imaging that we had intended
to achieve in the present WF/PC. 

     It is too early to state just what changes may be required in the
HST observing program.  The Project must thoroughly quantify the
present performance of the observatory , and NASA and the Space
Telescope Science Institute must reexamine their plans for observatory
usage.  In the meantime, I wanted you to read the facts as I know
them.  I encourage you to continue monitoring Ron Polidan's HST news
reports on email and the ST Science Institute's reports for new
information as it becomes available. 

                                       Albert Boggess                 
                                       Project Scientist for HST 



**************************************

                         POSITION PAPER OF THE
                       HST SCIENCE WORKING GROUP
                      AND THE HST USERS COMMITTEE

                              JUNE 29, 1990


SUMMARY

     Our groups met jointly on June 27 and 28, 1990, at the GSFC and
received reports from key Project personnel about the status of the
Hubble Space Telescope, with particular emphasis on the imaging
performance. Although the program has clearly suffered a major setback
due to telescope optics that are well below specification, we are
convinced that the long-term prospects for completion of the science
program are highly encouraging.  Furthermore, a valuable subset of the
scientific program can be executed with the telescope even in its
present state, with the result that HST still has the potential to
produce many key discoveries in the near future. 

     HST right now has capabilities that vastly exceed ground-based
observatories. Most important are spectroscopy, photometry and imaging
at ultraviolet wavelengths, none of which are possible at all from the
ground.  High resolution visible-light imaging on bright objects will
also be possible, achieving to some degree the original fine details
expected in HST pictures. 

     For the longer term, it appears highly probable that the full
imaging capabilities of HST can be restored by straightforward
modifications to the Second-Generation Scientific Instruments.  These
are already under development as Orbital Replacement Instruments
(ORIs), to be installed in the observatory over the next several
years.  We recommend that the development of these ORIs be accelerated
as much as possible.  With determined effort, the WFPC-II camera could
be installed in as little as 2 1/2 years, producing images that meet
the original design goals. 

THE OPTICAL CAPABILITY

     We understand that there is approximately one-half wave rms
spherical aberration error (2 micron center-to-edge surface error) in
the OTA wavefront, leading to images that fail to meet the Level I 70%
enclosed light specification by roughly a factor of 7.  The observed
image radius is 0.7", versus a specified radius of 0.1".  For certain
focal positions, the images possess sharp cores (~0.07" FWHM), so that
at some level the high spatial resolving power of HST is preserved. 
However, these cores contain only ~15% of the light, the remaining
light being dispersed over a wide halo comparable in size to
ground-based images.  A summary of what capabilities for science are
allowed by these image properties and what can be done to recover the
full Level I performance of the observatory is given below. 

THE SCIENTIFIC CAPABILITIES

     HST is an extremely versatile observatory with many modes of
observation.  Loss of image quality has damaged some of these, modes,
but many remain wholly or largely intact.  Temporarily being able to
use only certain of these modes will not alter the fact that we will
still be able to do forefront science 100% of the time, but the
initial scientific emphasis will have to be different.  The number of
programs that can be done with the HST has always greatly exceeded the
time available for their execution, and this remains true even with
the telescope in its current state. 

     The near-term observing plan will now have to give greater
emphasis to ultraviolet imaging (FOC), ultraviolet spectroscopy (FOS
and GHRS), and ultraviolet photometry (HSP), plus the use of bright
core images in visible light (WF/PC and FOC).  These, plus the ongoing
astrometry program (FGS), will easily occupy all the time available
and will return scientific results of great interest and utility.  The
fulfillment of the original imaging programs will still be possible,
but will largely have to be scheduled later. 

     These near-term programs are possible because HST, even in its
present state, has unique capabilities that cannot be matched
anywhere, either in space or on the ground.  The core of the sharply
focused image can yield sharp pictures for bright, high-contrast
objects such as stars and galactic nuclei.  The ultraviolet
spectroscopic capability is still largely intact, although some
trade-offs are now involved.  Obtaining spectra at the planned
spectral resolution and desired signal-to-noise will be possible, but
the targets will have to be brighter, or the exposure times longer. 
Spectra of faint targets should also be possible, although with some
loss of spectral purity.  Fortunately, many programs of the HSP will
not be impacted, and the astrometry capability of the FGS will
apparently not be compromised at all.  Realizing these capabilities
will require some new effort; for example, it will be necessary to
revise target acquisition methods for the small-aperture instruments
and to develop image deconvolution algorithms far the cameras.
However, these are not major tasks. 

     Most encouraging of all, it should be possible ultimately to
realize the full capability of the HST through the use of the
Second-Generation Scientific Instruments (SIs).  The WF/PC-II
instrument that is currently planned for flight some 3 years after
launch has an optical design that will permit complete correction of
the errors in the OTA.  The other two new Scientific Instruments, both
already in development, will also be able to correct simply for the
limitations of the telescope optics.  The NICMOS instrument will
extend the wavelength range of the HST and open up a new window to
infra-red observations.  The STIS instrument will expand the
spectroscopic power of the HST by at least an order of magnitude
beyond the goals for the first generation of spectrographs. 
Completion of all three of the Second-Generation Instruments is now
clearly more urgent than ever. 

CONCLUSIONS AND RECOMMENDATIONS 

     While some of the important scientific goals of the Hubble Space
Telescope are currently not achievable because of the spherical
aberration in the telescope optics, other unique scientific goals do
remain viable, and HST therefore still has the potential to produce
many important discoveries during its first years of operation.  The
original goals for the 15-year mission of the HST continue to be
achievable.   We therefore recommend that all necessary actions be
taken to insure that HST will operate as productively as possible in
the short-term, and that activities directed at restoring full
capability over the long-term be pursued vigorously.  In the short
term, this means that on-going HST operations must be fully supported
and that the telescope and instrument performance evaluations and
analyses must be continued.  We also need to adjust to the larger
images by developing new target acquisition techniques and by
modifying various other capabilities as indicated by the results of
ongoing studies. 

     For the longer term, it is clear that the full imaging
capabilities of HST can be restored  by suitable modifications to the
Second-Generation Scientific Instruments, which are planned as Orbital
Replacement Instruments (ORIs), to be installed in the observatory
over the next several years.  We recommend that the development of
these ORIs be accelerated.  Finally, we recommend that the first
Maintenance and Refurbishment Mission, which will install the WF/PC-II
in place of the original WF/PC, be directed to proceed as
expeditiously as possible, with the goal of being completed in less
than 2 1/2 years rather than the planned 3-year schedule. 

     By way of conclusion, we would like to emphasize that an enormous
number of technically difficult challenges involved in the design of
HST have been successfully met.  These include the basic smoothness of
the optics, the high degree of accuracy required from the Pointing
Control System, and the proper functioning of a suite of complex
scientific instruments, to name only a few.  In comparison to the huge
investment already made in HST, the effort involved in correcting the
optical aberrations is fairly small.  In comparison to the planned
15-year lifetime of HST, the few-year delay until delivery of WFPC-II
is also small.  With this perspective in mind, we feel it is important
to keep our eyes on the long-term future and work diligently to
realize the full potential of the observatory, which is still a fully
viable goal. 


For the HST Science Working Group      For the HST Users Committe
        Albert Boggess                      Arthur Davidsen

****************************************************************************************************************************************************************Posted by: Eric Jaderlund
           University of New Mexico
           Dept. of Physics and Astronomy
           [email protected]
********************************************************************************

From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.top
Date: 4 Jul 90 04:17:31 GMT

	WASHINGTON (UPI) -- Mysterious Pluto may be an early target of the
Hubble Space Telescope as NASA forges ahead to determine how flaws in
the $1.5 billion observatory's crucial mirrors will limit its scientific
achievements.
	Hubble project scientist Ed Weiler said the space agency plans to
move the first tests of the telescope's scientific powers ahead to
August or September to explore how well it performs encumbered by mirror
difficulties that blur its view of visible light. The scientific tests
will be interspersed with already scheduled tests of the telescope's
hardware.
	``We want to characterize each of the scientific instruments in
most of their modes to see if we are being overly optimistic or
pessimistic in the terms of the science we can do,'' said Weiler,
explaining why the scientific work was being pushed forward.
	Among the early goals may be to try to get the first pictures of
the surface of Pluto, the solar system's smallest and usually most
distant planet.
	``If Pluto is available (in the telescope's viewing range), we
probably will go up and take pictures of Pluto in the next three or four
months,'' Weiler told a telephone news conference Tuesday. ``It's worth
a try to see what we can do on it.''
	Ellie Lange, a spokeswoman for the Space Telescope Science
Institute in Baltimore, said Pluto and its satellite, Charon, appear
reasonable targets for Hubble. Pictures taken by the telescope's Wide
Field/Planetary Camera or WFPC would likely show ``some planetary
features,'' although they would not be ``terribly clear,'' she said.
	``Of course because astronomers currently do not have any pictures
of Pluto, anything we see would be better than what we have,'' Lange
said.
	Pictures that Hubble takes of Pluto and other cosmic objects
probably would have to be reconstructed by ``fancy'' computer processing
on the ground, Weiler said.
	``We may not be as bad off as we thought,'' Weiler said. ``In some
cases ... we probably could process an image to get back to our original
one-tenth of an arc second resolution,'' or clarity.
	That means despite the gloomy early assessment that Hubble could
produce no pictures for two or three years, the telescope may soon be
able to crank out a few of the ``pretty pictures'' the American public
was told to expect, Weiler said.
	Weiler announced the formation of a team of computer experts from
NASA, the University of Rochester, the Smithsonian Astrophysical
Observatory and elsewhere to see if clear images can be reconstructed
from the blurry pictures taken by the telescope in its current state.
	``We're going to let the experts play with the images and see what
they can do. People who know field say there is a lot of hope,'' Weiler
said. But he conceded that generating pictures by such a route probably
would take more observation time and be more expensive due to computer
costs.
	Image reconstruction likely would succeed best on cosmic objects
that are fairly bright and not close to other objects, Weiler said.
	Although last week's discovery of the crippling mirror flaws
generated initial reactions of despair and frustration, Weiler said
scientists on the project are generally optimistic that they can wring
some pictures out of Hubble even before a shuttle repair mission is sent
up in 1992 or 1993.
	``The Wide Field/Planetary Camera is still about 10 percent to 20
percent usable. Reports of the early death of WFPC were greatly
exaggerated,'' Weiler said. ``Scientists are fairly optimistic and feel
roughly 50 percent of the science originally proposed for the first one
or two years can be done.''
	Even when it appeared WFPC's picture-taking ability would be
completely knocked out during the first few years of Hubble's 15-year
life, NASA had emphasized that the big observatory would still produce
``world-class science'' by tracking non-visible energy like ultraviolet
light.
	``I must admit some of the negative media we have received has
spurred some of us on. A lot of us feel like Harry S. Truman: The votes
haven't been counted, but we're all being called losers,'' Weiler said.
	Hubble's problem, called spherical aberration, apparently occurred
some 10 years ago during construction of its two light-focusing mirrors
by what is now Hughes Danbury Optical Systems Inc. of Danbury, Conn.
	Engineers say spherical aberration is relatively easy to fix and
that new cameras now under development can be modified to correct for
the flaw before they are installed by a space shuttle in several years.
	In the meantime, Weiler said NASA has managed to work out most of
the other technical glitches that plagued Hubble in its early days after
its April 25 launch, and is confident it can iron out a vibration still
troubling the telescope when it goes from light to dark by early August.
	Also Tuesday, NASA officially announced formation of an independent
panel to investigate the Hubble's problems. No deadline was given for
the committee's final report.
	The committee's chairman is Lew Allen, director of NASA's Jet
Propulsion Laboratory in Pasadena, Calif. Other members are Charles
Spoelhof, retired vice president of Eastman Kodak Co., Pittsford, N.Y.;
George Rodney, NASA's associate administrator for safety in Washington;
John Mangus, head of the optics branch, NASA Goddard Space Flight Center
in Greenbelt, Md.; Bob Shannon, astronomy professor, University of
Arizona-Tucson; and Roger Angel, also astronomy professor, University of
Arizona-Tuscon.

From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.gov.usa,clari.tw.science,clari.news.top
Date: 6 Jul 90 19:08:51 GMT

	WASHINGTON (UPI) -- NASA officials, awaiting results of an
investigation into the mirror flaws plaguing the Hubble Space Telescope,
refused Friday to comment on reports the space agency passed up chances
to test the mirrors on the ground.
	Sources quoted in Aviation Week and Space Technology's July 9 issue
said the Air Force offered NASA use of its spy satellite mirror test
facilities to check the $1.5 billion space telescope's mirrors 10 years
ago.
	But NASA turned down the offer because the Air Force wanted all
NASA and private industry personnel associated with the tests to obtain
top-secret military clearance, the sources said.
	``Current management does not confirm or deny such reports,'' said
Paula Cleggett-Haleim, a spokeswoman at NASA headquarters.
	When the Hubble troubles were first revealed last week, The New
York Times also reported NASA had decided against using military
equipment for pre-launch tests of the mirrors, which are vital to
Hubble's ability to take pictures of visible light.
	Top Hubble managers, most of whom were not with the agency when the
mirrors were ground a decade ago, think the findings of a special review
board will figure out exactly what went wrong with the vital mirrors and
determine why on-ground tests were not conducted, Cleggett-Haleim said.
	The six-member investigative panel, which has impounded records and
equipment from the mirrors' maker, now known as Hughes Danbury Optical
Systems Inc. of Danbury, Conn., met for the first time Thursday and
Friday in Washington.
	The Air Force facilities rejected by NASA were used in the 1970s
and early 1980s to test the optical systems of Lockheed/Kodak KH-9
strategic reconnaissance satellites, the Aviation Week article said.
	In another published report, Robert O'Dell, the original chief
program scientist for Hubble, said spending limits restricted costly
ground testing that might have revealed the erroneous shape of the
mirror system before launch.
	``All along in the program we were money limited,'' O'Dell said in
Thursday's editions of The Houston Chronicle. ``We were continuously
forced to do it in the cheapest possible way that we thought we could do
it.
	``There were lots and lots of stuff we knew and the contractor knew
that we'd like to do, but when it was reduced to the push and shove, you
didn't include that,'' said O'Dell, now an astronomy professor at Rice
University.
	O'Dell assumed leadership of Hubble in 1972 and held that post at
Marshall Space Flight Center in Huntsville, Ala., for a decade. The
center was responsible for Hubble's overall development.
	Many critics from lawmakers to scientists have questioned why the
mirrors were not tested in tandem on the ground before launch, an
exercise Marshall engineers estimate would have cost about $200 million.
	``We were spending about $100 million a year at the time (on
Hubble),'' O'Dell said. ``Therefore, paying an insurance premium that
you didn't really think was necessary and which exceeds your annual
budget seemed irresponsible.
	``Like all insurance policies, after things go awry, then the
premium on that insurance policy looks pretty cheap.''
	Hubble's problem, called spherical aberration, apparently occurred
during construction of its two light-focusing mirrors. Engineers say new
cameras scheduled to be installed in the telescope by a space shuttle in
1992 or 1993 can be modified to compensate for the flaw.
	Although the discovery of the mirror flaws prompted initial
reactions of despair, Ed Weiler, the current project scientist, said
astronomers think they can wring some pictures out of Hubble even before
a shuttle repair mission is sent up in several years.
	Those hopes hinge on the likelihood that ground-based computer
processing might be able to reconstruct clear images from the blurry
pictures produced by the telescope in its current state.
	``Scientists are fairly optimistic and feel roughly 50 percent of
the science originally proposed for the first one or two years can be
done,'' Weiler has said, suggesting that computer processing techniques
may be able to reconstruct clear images from some of the blurry pictures
taken by Hubble in its current state.
	NASA has also emphasized that the big observatory, which has a
projected life span of 15 years, can still produce ``world-class
science'' by tracking non-visible energy like ultraviolet light.

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Date: 6 Jul 90 22:09:23 GMT

HST INVESTIGATION BOARD STATUS REPORT #1
 
     The Hubble Space Telescope (HST) Optical Systems Board of 
Investigation met for the first time July 5-6, 1990, in 
Washington, D.C.  After introductory remarks by Dr. Lennard A. 
Fisk, Associate Administrator for Space Science and Applications; 
Dr. Lew Allen, Director, Jet Propulsion Laboratory (JPL), and 
board chairman; and Gary Tesch, Board Counsel, the board heard 
presentations from NASA Marshall Space Flight Center (MSFC) and 
Hughes Danbury Optical Systems (DOS) officials.
 
     The MSFC personnel summarized the current status of HST 
systems.  The Hughes DOS representatives gave an overview of the 
manufacture and test procedures for the HST primary and secondary 
mirrors and the Optical Telescope Assemby (OTA). The 
presentations were general in nature due to the impounment of 
original pertinent data under the provisions of the HST 
Contingency Plan.
 
     Hughes DOS officials also proposed some near-term options 
for further defining and characterizing the spherical 
aberration.  Some of the options which were extensively discussed 
by the board involve data review; others call for testing of
existing back-up and prototype hardware and test equipment.
 
     The board heard by telecon the report from the HST
Independent Optical Review Panel, concluding that the panel
agrees that there is approximately one-half wave of spherical
aberration in the OTA.
 
     The next meeting of the board is tentatively scheduled for
July 25-26, 1990, at Hughes DOS, Danbury, Connecticut.  In the
next two weeks activities will be carried out in three areas:
 
       o Examination and analysis of pertinent data.
 
       o Preliminary interviews of knowledgeble individuals.
 
       o Design and preparation of appropriate tests.
 
     The board has modified the impoundment procedures
sufficiently to permit the activites above to begin while taking
active steps, including independent supervision, to ensure the
integrity of the pertinent data and hardware.
 
     At the conclusion of the meeting Dr. Allen said, "The board
now has a good base of information from which to proceed with its
investigation."
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Horowitz, Irwin Kenneth)
Newsgroups: sci.astro,sci.space
Date: 9 Jul 90 22:27:25 GMT
Organization: California Institute of Technology

I have just returned from a talk by Jim Westphal (PI on WF/PC) concerning the
present status of HST.  I will attempt to summarize his comments below.

The evidence from both WF/PC and the WFS data is that HST has about 0.5 RMS
wavelength of spherical aberration.  The source of the aberration is not
yet confirmed, however, the evidence strongly suggests that the primary is
the suspect.  The radii of curvature should be correct but there is probably
a 1% error in the eccentricity of the hyperboloid.

The aberration is not correctable by either using the mirror actuators on the
primary (which were specifically designed not to correct spherical aberration,
more on that below) or by replacing the secondary on orbit.  The simplest 
correction is to model the aberration using both the data from Hughes Danbury
and from actual observations with both WF/PC and the FOC in order to design
correcting elements for second generation instruments.

Needless to say, HST in its current configuration will not be able to achieve 
its Level 1 resolution requirements (70% encircled energy in 0.1 arc sec
radius).  The impact on science will be significant.

There is a choice of focus positions at present which either maximizes the
image core at the expense of spreading out the remainder of the image (70%
energy within 1 arc sec radius) or minimizing the spread of the PSF (70% 
within 0.6 arc sec) but reduces the image core.  This compares to the
predicted values of 70% within 0.15 arc sec (this includes the transfer
function for the Planetary Camera).  Which focus is eventually chosen is
still unknown (however, the final focussing is SCHEDULED to be completed 
next Monday).  Some image simulations using the measured PSF show that the
images are significantly degraded (not much better than ground based imaging).

The course of action is to model the aberration using WF/PC, FOC and the WFS
(however, 2 of the 3 WFS are giving garbage data and the third has variances
on the order of the measurements; the cause is not known).  FOC has the
advantage over WF/PC because of its position in the focal plane allows it
to measure any coma or astigmatism.  A detailed evaluation at Hughes Danbury
is underway to pinpoint the cause of the aberration in either the design or
fabrication documentation.

The actuators will not be used to correct for the aberration because it would
deform the mirror into a more complex shape, and would be harder to model
any new aberrations.  The final focus alignment is scheduled to be completed
next Monday (7/15) after which image plane testing should reveal the nature
of the aberrations.

The impact on science experiments I summarize below:
--Performance in visible light--
	Image quality somewhat better than typical ground based telescopes
	HST images very stable, permitting possibility of image deconvolution
	Many HSP observations are viable (however, lunar occultation studies
		are unpromising)
	Many astrometry objectives are viable
	Most spectroscopy better done from the ground
--Performance in UV light--
	FOC gives worthwhile images (photon counting system, no read noise
		coupled with low UV sky background), WF/PC is marginal (CCD
		has read noise, can observe UV bright objects)
	FOS and GHRS give excellent spectra with some loss of either spectral
		resolution or S/N
--Future Possibilities--
	Some ORI's (orbital replacement instruments) able to correct aberrations
	WF/PC II CAN RECOVER FULL IMAGE PERFORMANCE, team looking to correct
		the secondary on their Schmidt Cameras
	STIS can achieve good spectroscopic performance in both visible and UV
	NICMOS can achieve good IR performance

One of the problems caused by the aberration is that image acquisition for 
the axial instruments needs to be reevaluated (the original plan was to use
WF/PC to center the target on the entrance apertures of the different 
instruments).  This will lead to lower efficiency in time usage of HST as they
search for the targets.  

For the UV spectrographs, there is a choice of either using a narrow (0."25)
slit which enables full spectral resolution at a loss of efficiency (~8x)
thus requiring an increase of 64x in integration to achieve the same S/N.
Otherwise, you can use a wider slit (2") which leads to a loss in resolution
(which might be recoverable using deconvolution techniques).  A word of 
caution on image restoration concerning photometric accuracy:  the talk of
regaining image quality using various CLEAN type algorithms must be tempered
by the fact that photometric integrity is lost during such processing (images
look better, but the data is more suspect).

The conclusion on UV spectroscopy is that it is doable but at a cost in
efficiency and reliability.

The impact on FOC programs:
	Total number of GTO programs  :   62
	Programs 100% feasible        :    6
	Programs  50% feasible        :   34
	Programs  20% feasible        :   10
	Programs not feasible         :   12
All FOC programs will require a 3-5 times increase in integration time to 
achieve the original S/N.  They will stress UV imaging (which can't be done
from the ground).

The evidence that the aberration is in the OTA and not in the WF/PC is that:
	all WF/PC cameras show the same error; 
	test points in the instrument are undistorted (so that the optics in 
		the cameras are OK); 
	positional variations in image quality in both the WF and PC agree 
		that the error is in the OTA;
	FOC images show the same core-halo structure; 
	fringe visibilities consistent with OTA spherical aberration; and
	ability of FGS's to achieve fine lock is asymmetric with respect
		to nominal focus and consistent with OTA spherical aberration.
Therefore, don't lynch the instrument teams :-).

The primary mirror actuators consist of 2 rings of 12 force actuators capable
of 10 lbs of force each.  They are located at 0.5 and 0.87 radii, at the nodes
in the spherical aberration curve.  This was done intentionally, so that if
the primary had any residual astigmatism, then moving the actuators would not
introduce any unwanted spherical aberration (of course it also means that you
can't introduce any wanted SA either :-)).

For WF/PC II, the compensation is best accomplished using the relay secondary
mirrors (suggested by A. Meinel).  Assumptions are that the HST mirrors are
stable and an accurate wavefront error map can be obtained on orbit.  The
apparent error is consistent with a simple error in the conic constant of
one of the two mirrors (probably the primary).  IT IS ENTIRELY REASONABLE TO
ASSUME THAT IF THE WAVEFRONT ERROR IS CORRECTLY MAPPED, THAT COMPENSATING
OPTICS CAN BE INTRODUCED IN WF/PC II TO FULLY CORRECT FOR THE OTA's SPHERICAL
ABERRATION (emphasis mine).

What could have been the cause?  The original design is OK (instruments were
built according to that design), so the error is probably in the conic
constants used to manufacture the primary (most likely the eccentricity).
Conjectures by Dr. Westphal were that it was a "low-tech" error, like 
mistyping the figures into the computer that controlled the mirror grinding,
or that the glass used for the null-corrector (a testing device) had an
incorrect index of refraction (mislabelled on the shelf!).  He pointed out 
that the NTT (New Technology Telescope of ESO) had a similar problem that
was traced to the null corrector being systematically placed 1.8mm away from
its proper position when testing the primary!

To the poster who inquired as to whether the tests were done in vacuum, they
were (they had this big chamber set up at PE for this).  Some tests were not
possible, because of the size of the primary and the level of precision 
required.  There is both a second primary (built by Kodak) and secondary on
the ground, but there will be no attempt to bring HST back down and replace
the OTA (it would be cheaper to just build another HST!).

Some of the early problems with the scope were due to the use of a star catalog
that had serious errors in the entries, so STScI generated a new catalog 
on-line in order to correct this.  The motion of the solar arrays is due to
the double layer used on the support struts (one inside of the other) which
move relative to each other when undergoing a temperature change.  This should
be corrected by just moving the entire telescope out of phase of the motions
of the solar arrays and cancelling the motion.

Finally the one big question brought out at the end was the question of why 
the primary wasn't tested for spherical aberration.  I don't know...(but we
should eventually find out).
-------------------------------------------------------------------------------
Irwin Horowitz                        |"Suppose they went nowhere?"-McCoy
Astronomy Department                  |"Then this will be your big chance
California Institute of Technology    | to get away from it all!"-Kirk
[email protected]               |       from STII:TWOK
[email protected]                 |
-------------------------------------------------------------------------------

                         Hubble Space Telescope Update
                                July 6, 1990
 
     The biggest event with the Hubble Space Telescope (HST) in the past week
was a spacecraft safing event (specifically, a software sunpoint with the +V3
axis toward the sun) that occurred at 2:25 PM EDT on July 5.  All the
Scientific Instruments (SI) and spacecraft subsystems are fine, recovery
is underway.  The cause of the event was human error:  a series of 6 Fixed
Head Star Tracker (FHST) updates failed (cause under investigation) resulting
in a small 100 arc second attitude error, a real-time slew was requested to
correct the pointing, somehow, in PASS/OPS, the final attitude of an earlier
slew entered the system as the final position of the short real-time slew,
checks of the maneuver failed to uncover the error (due in part to the fact
that there is no easy way to check either the slew length or end point), as
a result a request for a 90 DEGREE slew was sent to the spacecraft, the slew
was executed and upon completion of the slew the spacecraft onboard computers
noted that the sun was not normal to the solar panels, concluded that the
ground controllers did not know what they were doing and safed itself.
Recovery is underway, the telescope is in a Health & Safety load until 1 AM
EDT July 7.  Not surprisingly, steps are being taken to prevent this type of
error from occurring in the future.  A day before this safing event there
was a SI safing: The Faint Object Spectrograph (FOS) safed because of a
microprocessor reset.  The data on this safing event is under investigation.
Efforts to get Faint Object Camera (FOC) images in support of the focus
analysis have failed completely due to a combination of human error and
Fine Guidance Sensor (FGS) acquisition failure.  Before their safing event
FOS successfully brought up full high voltage on the Blue detector with no
anomalies or surprises.  Because of the safing event a number of scheduled
SI testing never executed.  This weekend the telescope will recover from
the safing event and begin more Bootstrap focus measurements.
 
     Nothing new regarding the Pointing Control Subsystem (PCS) day/night
terminator instability fix.  It is obvious that the FHST's are still a major
problem.  The effort to understand how best to operate these star trackers is
in progress, and it is expected that this problem will not totally disappear
until a few more pointings are done.  A few FGS failures are still ocurring
for currently unknown reasons, investigations of these are underway.  A
major effort is now underway to document and analyze all FHST and FGS
failures.  One good note on recent PCS activities: the software that fixes the
South Atlantic Anomaly (SAA) induced "bit flips" in the FGS's seems to be
working quite well.
 
     A major new activity here has been the attempt to get FOC images in
support of the focus study.  Unfortunately, this effort has yet to produce
anything very useful.  The initial FOC field contained stars that, due to
human error, had magnitudes that were too faint (by 3-4 magnitudes) to give
good image quality.  These exposures also suffered from failed FGS fine lock
acquisitions.  A second field was chosen, this time containing stars of the
appropriate brightness, but FGS acquisitions again failed and no useful data
was obtained.  The HST safing event halted any further attempts.  The Bootstrap
Science Mission Specifications (SMS) that have been running this week obtained
a number of wavefront sensor measurements (WFS) (WFS1 is still giving good
data and WFS2 and 3 are still giving bad data), some additional Wide Field
Planetary Camera (WFPC) images have also been obtained. In summary, there
has been little new data obtained in orbit and little new in the analyses
of the existing images.  The first opportunity at new information on the
HST image quality will probably be in the middle of next week.
 
     The FOC tried three times to take images this week but, while they did
get a few stars in their first image none of the data was usable due to the
very low count rate.  There were two problems: due to human error the stellar
brightness was overestimated and the stars were too faint by 3-4 magnitudes,
in addition failed guide star acquisitions kept the "take data" flag off during
all or part of the exposures.  Analysis of the one image that showed stars
yielded a pointing error of ~4 arc seconds, similar in magnitude to an earlier
image, but in a different direction.  This, too, is under study.  A third set
of the FOC images on a brighter star failed because of a failed acquisition.
 
     FOS successfully turned on their High Voltage (HV) on the Blue side.
All went very well, dark count was as expected, no anomalies, no surprises.
Then on July 4 the instrument safed itself.  Analysis of the data showed that
the safing event was triggered by a microprocessor reset.  There is no history
of this in the FOS, the last reset event occurring in thermal vacuum tests.
The data is under study at this time.  At this time, the FOS team does not feel
that the reset is not indicative of any fundamental failure.  Blue side Coarse
Y-Base measurement and SAA noise measurements were not run because of the
safing.  It will probably be a week before the FOS gets back in the SMS's.
 
     The Goddard High Resolution Spectograph (GHRS) has been doing a series of
HV electronic dark count tests skirting the SAA.  All went well.  These tests
were also cut short by the HST safing.
 
     The High Speed Photometer (HSP) proposals were also hit by the safing.
One more Photomultiplier Tube (PMT) test gave the same (expected) results.
 
     WFPC is awaiting recovery from safemode.  A few images were taken this
week in support of the focus testing.  The next run of WFPC diagnostic
images are scheduled for July 9.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Eric Jaderlund)
Newsgroups: sci.space,sci.astro
Date: 10 Jul 90 17:10:35 GMT
Organization: University of New Mexico, Albuquerque

	WIFFPICKERS:   NEWS.709		~17:00 9 JULY 90



                               HST Status Report
 
                                  Number 60 
                                 09 July 1990
 
 
Current Status and Summary  
 
This past weekend has been rather quiet at HST.  Since my last report we
finished Bootstrap Phase B part 5f and started part 5g.  The biggest event of
the past few days occurred yesterday evening and today: a successful series of
FOC exposures.  Stars were seen with good S/N and excellent overall data
quality.  Very preliminary analysis suggests that significant coma was NOT seen
in the images, suggesting that the primary mirror is the source of the
spherical aberration (see below).  Another piece of good news regarding the
characterization of the HST wavefront: modifications to the procedures for how
we have been using wavefront sensors (WFS) 2 & 3 have produced the first good
data from these sensors since launch.  The only piece of bad news was that some
WFPC images were lost do to a series of operations events that could have been
avoided.  This and the safing event of last Thursday has people taking a long
hard look at real time operations procedures.  
 
  
PCS 
 
The only news on the PCS front regards the day/night terminator instability
fix.  A meeting has just concluded discussing current expectations for the new
control law.  Optimism is still high that they can meet pre-launch specs, but I
have noted that they have backed off a bit on how much they can reduce the
disturbance amplitude from an informal quote ~2 weeks ago of a 10 to 100
reduction to a current guess of a 5 to 60 reduction factor.  The current worst
case disturbance is ~110 milliarcseconds RMS (2 milliarcsec RMS is the spec
value).  As of the moment the repair is on schedule with delivery to GSFC in
late July/early August.
  
 
HST Focusing and Image Quality
 
The big news here is the successful series of FOC images: 4 last night and 4 (I
think) this afternoon.  The images were through a narrow (30 A) H-beta filter
of a 12-13 magnitude star near eps Sco.  Analysis has just begun, so there are
no quantitative results.  The images have good S/N and should yield excellent
data.  The images are quite similar to those taken with the PC: a sharp with a
big (~1.5-2 arc second) halo with lots of rings, rays, and the such.  A quick
look at the data seems to show a stellar image that is similar (in gross
detail) to the PC images with no obvious asymetry (i.e. coma).  If this is
confirmed with quantitative analysis, it would suggest that the primary mirror
is responsible for the spherical aberration.  There is also a rumor circulating
that suggests a possible origin for the spherical aberration: it has been
reported that if the null lens used to test the primary were installed
backwards that you would get a degree of spherical aberration similar to what
is seen in HST.  Obviously, more on this later.  The only mirror movements have
been to move the secondary to the "zero reference" position -- the favored WFPC
focus position.  More mirror movements will be occurring this week now that we
have FOC images.
 
 
Thermal
 
All is fine as usual.
 
 
Power
 
No changes -- still excellent.  
 
SMS's
 
SMS production was running rather tight at the moment.  We are currently in a
Bootstrap SMS (part 5g).  It expires Tuesday afternoon (EDT).  The follow-on
SMS, Bootstrap Phase B part 5h, is having difficulty.  There is a possibility
of either dropping a mini-OFAD at the beginning of this SMS or generating a
Health and Safety load.  Part 5h runs for ~84 hours and will be followed by
another Bootstrap SMS (5i).  The long term schedule looks like we will have
Bootstrap SMS's until at least 17 July.  During this period do not expect a lot
of SI activities.
 
  
SI's
 
Other than the WFPC and FOC focus support images there has been very little SI
activity.
 
AST is supporting variety of FGS and FHST investigations.
 
FOC was successful in taking their focus images.  Details are given above.
More images are scheduled for as long as the image characterization effort
runs.
 
FOS: I erred in my last report when discussing the FOS Blue side HV turn-on.
The microprocessor reset that safed the instrument occurred before full voltage
was reached.  The maximum voltage reached was 14000 volts (~half way).
Analysis of the safing event seems to indicate that a HV relay may be involved
in the microprocessor reset.  More investigation is planned.
  
GHRS has been quiet, expect GHRS proposals to appear again next(?) week.
  
HSP was in hold all weekend.  Next HSP activity will, likely, be next week.
   
WFPC is in full operate mode taking lots of pictures in support to the focus
effort.
 
That is all for today.  My next report will probably be issued on Wednesday or
Thursday.  
 
    Ron Polidan


THE FOLLOWING IS EXCERPTS FROM A NOTE DISTRIBUTED BY JIM GUNN - IT SPEAKS
TRUTH BY MY VIEW.  [Ed Note: not my opinions but I generally agree.  ECJ]

I think we are making a really dreadful mistake if we ignore the HST
fiasco; it may or may not be too late already in more ways than one, but
we have laid ourselves wide open to this disaster in the past and are
asking for it over and over again in the future, and I personally doubt
that the field can absorb another, if indeed it can absorb this one. 

My view and point are very simple.  We have lost all control of our
destiny, having handed it to a beauraucratic agency which means well
enough but is unable to handle large projects of its own (cf the
Shuttle) and certainly not of ours.  We were not 'screwed over'--we have
been exquisitely vulnerable to precisely this kind of thing happening
for years; it is a part of our sorry heritage which began with gentleman
astronomers in their coats and ties at Mount Wilson, continued with the
sorrier example of the national observatories, and has culminated with
the first of the Great Observatories, probably the most expensive
scientific failure in history.  We are a discipline of technical
incompetents, happy to let our or NASA's engineers build our tools to
their desires, by and large, not ours.  We are quite content to sit on
the sidelines while the work is going on and bemoan the incompetence
(often real, of course) of the people who are doing what should be our
work, and crow about inflated expectations about what these tools will
do, as if that would make it all real.  The smaller NASA missions which
have worked and worked well have had strong and close ties to the
scientists, but even that has not prevented cost and schedule from
climbing through the roof because of the ever-present aerospace
industry, whose last gift to us we may not survive swallowing.  And the
bitter financial pill which I think is likely coming over this will
affect everyone in the field, including all the people who have never
had the stomach (or perhaps had too much integrity) to play the space
game, so we who had anthing to do with the project, including the
not-so-few who worked very hard and the hordes who hardly worked, cannot
claim that we have done in only ourselves. 

It was an ASTRONOMICAL failure; it was an ASTRONOMICAL satellite, and it
does not matter a whit that it was probably some fool at PE that caused
it and some entirely expected failure of NASA's criminally infantile QA
program that failed to catch it.  It was two billion of astronomy's
dollars that flushed down the drain (let us not overreact--it may not
entirely go down the drain, but the chances that it can be fixed
PROPERLY are very small, and the ground is fast catching up.  We must
wait at least three years, making it, I think, an even ten years from
the first projected launch date, no ? and if I were a congressman, I
would think twice about giving another nickel without some evidence that
the discipline was at least aware of what had happened and had some
notion of what to do next time. 

John Bahcall told me about the contract and documentation for the SSC,
a project four times the size of ST. DOE wrote a FIVE PAGE specifications
document and on that basis will hand five or seven or eight billion
dollars to the PHYSICISTS to build the machine.  That, you protest, is not
NASA's 'style'. So it is not. NASA's style, however, is killing/may have 
already killed us, and we will never get another chance to do anything
about it, if indeed it is not already too late. Not that there would have
been enough technically competent people in the field to have taken the
two G$ and done anything with it if we had been given it, but if the field
had been up to snuff there would have been and it would have cost very
much less.

All this is a plea for a plea to get our house in order, to somehow
learn how to do these things before another disaster like this one
befalls us-- it may well be that we do not get another chance, but that
does not, I think, absolve us from (or render it a waste of time to)
spend some effort making ourselves slightly worthy of someone else's
effort on our behalf. 

If we choose to paper over this thing, as most of our colleagues seem to
be doing as fast as they can instead of facing the questions and problems
with some honesty and humility, I can only say that it is a sorry state of
affairs. You may certainly circulate this letter if you wish.

Jim Gunn

*****************************************************************************
end message


Hope this is helpful/illuminating/not-a-total-waste-of-time.

Eric Jaderlund
Univ. of New Mexico
Dept. of Physics and Astronomy
[email protected]

From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.top
Date: 10 Jul 90 21:16:04 GMT

	CAPE CANAVERAL, Fla. (UPI) -- A NASA official Tuesday denied reports
that use of military spy satellite test facilities was offered to the
space agency that could have revealed the Hubble Space Telescope's
blurry vision before launch.
	``No one stepped up, to my knowledge, and offered any facilities,''
deputy project manager Jean Oliver told reporters in a cross-country
teleconference from the Goddard Space Flight Center in Greenbelt, Md.
	Engineers studying the telescope's optical system, meanwhile, say
the ``spherical aberration'' blurring the instrument's vision appears to
involve Hubble's 94.5-inch primary mirror.
	Such a defect could have been caught before launch had Hubble's two
mirrors been checked out in an ``end-to-end'' test, but NASA officials
decided early in the program to forego such a procedure, presumably
because it would have added millions of dollars to the final price tag.
	Olivier said he was not aware of any offer from the Air Force to
make military spy satellite test facilities available to NASA for the
Hubble project, despite published reports to the contrary.
	Hubble program scientist Edward Weiler said engineers at Goddard
are using two cameras aboard the telescope to refine the observatory's
focus as much as possible and to establish which of the instrument's two
mirrors is producing the ``spherical aberration'' blamed for preventing
a sharp focus.
	``The optical experts ... think it is most likely in the primary
mirror,'' Lennard Fisk, associate administrator for space flight and
applications, told a Senate subcommittee Tuesday.
	The soft focus most seriously affects Hubble's two visible-light
cameras, limiting them roughly to the clarity of Earth-based
instruments. But three other instruments mounted on the telescope can
still do useful science, especially in the ultraviolet region of the
spectrum.
	As for the cameras, replacements are being built for installation
in 1992 or 1993 that can counteract Hubble's spherical aberration. In
the meantime, NASA is studying whether computer processing can improve
the performance of the cameras currently on board.
	``Starting sometime in mid August or perhaps late August, we're
going to start using all the instruments trying to characterize them for
science,'' program scientist Edward Weiler said.
	``That would include taking some pictures of some of these
high-contrast objects -- if Pluto's available, we might take a shot at
that -- and basically seeing what these things can do. Up to this point,
all the comments, negative and positive, on how much science we can do
is based on speculation,'' Weiler said.
	Olivier said data from photographs recently taken by the
telescope's cameras indicate the spherical aberration involves Hubble's
primary mirror, once billed as the most perfect ever built.
	``In all probability, we're going to find it's in the primary,'' he
said.
	The Hubble Space Telescope, built to push back the frontiers of
modern astronomy, was launched April 25 from the shuttle Discovery.
	Engineers immediately ran into problems with the giant
observatory's complex systems, including trouble with one of its
high-data-rate antennas, a sunlight-induced flexing of its giant solar
panels, stability problems and computer memory loss caused by Earth's
radiation belts.
	Virtually all the problems had been solved and engineers were in
the process of fine-tuning the telescope's focus when they discovered
one of the instrument's two supposedly near-perfect mirrors was flawed.
	Analysis revealed that when Hubble's mirrors were being ground and
polished in 1980 and 1981, a mistake was somehow made that gave one of
the mirrors a slightly incorrect curvature, one that was off just a
fraction of the thickness of a human hair.
	In telescope's suffering from such spherical aberration, light
striking the outer portion of the primary mirror is brought to a focus
at a slightly different point than light reflecting from the inner
region.
	In Hubble's case, the telescope cannot focus starlight much sharper
than ground-based instruments.
	While it can still carry out world-class ultraviolet astronomy,
visible-light photography using two expensive cameras will be sharply
reduced until modified instruments equipped with lenses that can
counteract Hubble's aberration can be launched in 1992 or 1993.

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military,clari.news.urgent
Date: 11 Jul 90 05:39:47 GMT

	WASHINGTON (UPI) -- Tests could have caught the mistakes that
crippled the Hubble Space Telescope and grounded the space shuttle
fleet, NASA officials said, but they denied the agency has a ``shoot the
messenger'' philosophy.
	At a crowded and sometimes tense congressional hearing Tuesday, top
space officials defended the agency's quality control efforts but
acknowledged that better testing could have prevented the problems.
	During one heated exchange, NASA Deputy Administrator James
Thompson also said that there was ``a very real possibility'' of another
major space shuttle accident within the next decade.
	The Senate Committee on Commerce, Science and Transportation called
the hearing to investigate a defect in the $1.5 billion Hubble
telescope's mirrors that produces blurry images, and fuel leaks that
have grounded all shuttles since May.
	``The common denominator is, in my view, inadequate testing,'' said
Sen. Albert Gore Jr., D-Tenn, who chairs the committee. ``In both cases
the testing program ... was not handled in a way that caught things
which have now shaken the public's view of how this is being managed.''
	Although the long-awaited, highly publicized Hubble telescope
underwent extensive testing before being sent into space April 25, the
instrument that scientists hoped would revolutionize astronomy was never
tested as a whole.
	In addition, NASA's William Lenoir, associate administrator of
space flight, said leaky fuel system parts on the shuttles Columbia and
Atlantis were among 18 of 27 units -- including seven in a row -- that did
not pass initial tests.
	But Lenoir stressed that the units passed subsequent testing,
although he said those tests may have been flawed because they did not
exactly simulate the conditions the hardware is exposed to on the launch
pad and in flight.
	``I don't think there is any question that any problem that we
encounter we can't trace it back to some fundamental issue associated
with lack of testing,'' said Thompson.
	``I'm as convinced as you are that more testing just has got to be
done. But each day we are faced with these decisions and we make what we
believe is the right judgment at the time,'' he said.
	Lennard Fisk, associate administrator for the office of space
science and applications, said the telescope was not tested as a whole
because it would have been too expensive and risky for the sensitive
mirrors.
	But Gore said it was routine to conduct such tests and pointed out
that one company that bid to build the mirrors said it could have
conducted such a test for $10 million.
	``People say, `My word. When a car comes off the assembly plant ...
someone gets in and turns the ignition to see if it goes varoom or
whatever.' It's hard for a layman such as myself to understand why the
space telescope was never tested as a total system,'' added Sen. Larry
Pressler, R-S.D., a committee member.
	In retrospect, such a test ``could have been done and should have
been done,'' Thompson said.
	Gore also questioned whether the National Aeronautics and Space
Administration had adopted a ``shoot the messenger'' attitude in which
officials dismissed negative or pessimistic test results.
	Gore cited a study that estimated there was a strong chance that a
space shuttle and crew would be lost within the next four years.
	``NASA shoots the messenger and says, `That study's wrong. Don't
believe it,''' Gore said. ``We're no longer going to be satisfied with
NASA saying, `That test is not to be believed.'''
	During the heated exchange, Thompson denied officials had ``the
wrong mindset at NASA'' and acknowledged there was ``a very real
possibility'' of ``at least'' the need to abort a flight after launch, a
dangerous situation.
	The possibility of such a mishap has raised questions about NASA's
plans to build the $30 billion space station Freedom, which would
require numerous shuttle missions.
	``I have stated that it won't be too long before we have another
accident,'' Thompson said, which prompted Gore to respond: ``Wait a
minute. Are you saying that you accept the fact that there is an 88
percent chance of losing a shuttle and crew with the number of missions
needed to build the space station?''
	Thompson said: ``Senator, I'm not going to get into the numbers
game, but ... let me just say this because I'm going to come damn close.
At the time of the Challenger accident the reliability was 96 percent.
At the flight rate over the next decade of 100, 120 missions, very
clearly at those unreliabilities or reliabilities we're going to lose
another one.''
	The committee also heard testimony from officials from the Hughes
Danbury Optical Systems, Inc., of Danbury, Conn., which built the
mirrors, and the Lockheed Missiles and Space Co., Inc., which built the
telescope.
	John Rich, president of Hughes Danbury, said the company built the
mirrors to NASA's specifications and the agency approved every aspect of
the construction and testing.

At least NASA seems now to acknowledge the liklihood of another shuttle loss.
What needs to be done (IMHO) is to make sure that the actual planning gets
done taking that into account, and that Congress and the public realize it.
We have to recognize that space is still risky.  The Navy does not pull in
all their ships and go home when one of them has a fire.  We must do our best
on the shuttle, but accept that there is risk.  And thus, we have to cut with
the "one-of-a-kind" satellites.  Is it really right to have had only 1 HST,
1 Galileo, 1 Magellan, 1 Ulysses and only 4 shuttles when each flight has a 2%
chance failure?

Burns 

Of course, no one mentions that NASA has to skip a lot of stuff because Congress
keeps cuting back on a year-by-year basis.  If they had a guarnateed amount of
money over a multi-year cycle, it would be a lot easier to make the right trade-
offs.

Burns

    Remember, too, that a 96% reliability exists for EACH flight.
    That reliability is NOT dependent upon the success or failure of
    previous launches. An analogy would be that if you flipped a coin
    6 times and got 'heads' six times, the probability of another toss
    being 'heads' is STILL 50%, since nothing in the previous 'tosses'
    changes the ability of the coin to produce only one of two results.
    
    Probabilities ONLY produce likelihoods. FACTS are more important,
    except to Congress-folk. Unfortunately, Congress controls the money.
    
    Each launch has a chance for failure. There are tens of thousands
    of parts which can fail, and certainly can fail in unexpected ways.
    
    As was cited in .109 above, the Navy does not pull all its ships
    home after an accident. Neither does the FAA ground all 747s for
    2+ years after an accident that kills several hundred people.
    
    Life is risky, and new explorations are even riskier. We must
    re-gain the courage we had 50, 100, and 200 years ago when men
    and women were found willing to explore new things and to risk their
    lives in the pursuit of 'something better.'
    
    The alternative is to stick our heads in the sand and bemoan our
    (willful) loss of opportunities.
    
    John B. 
    
    

  Pluto sure would be fun to see, but wouldn't it make more sense to point it
at Tritan since we already know what that looks like? It would give a much
better clue as to the degree of the optical problems since they would know what
they were looking at. 

  They are still playing politics.

  They never learn.

  George

    Re:.112
    	The reason they want to point towards Pluto is because it would be
    a good test of the imaging capability to resolve Pluto and its moon as
    two objects. Even if the optics were working perfectly, Pluto itself
    would only be seen a a VERY small disk three or four pixels in
    diameter. In its present state,  HST will be lucky to see Pluto as a
    disk never mind see any details on it. Pointing it at Triton (whose 
    surface we know something about) would not really be a good test because 
    not much of anything (if anything) could be seen anyway.
    
    					Drew

    Hmmm...do you suppose Mars with Deimos and Phobos would be an
    appropriate test? Or is it not well placed now vis-a-vis the sun?
    
    jb
    

Hi all...

I have read this whole note_subject, and what I fail to understand is the 
issue of Quality.  I have seen the pictures in the various magazines that have 
shown some of the pictures taken todate fron the HST.

In "discovery" magazine (a kids type of publication) they showed pictures of 
the double star cluster both from ground based telescope (100 inch i don't 
know which), and in each case the HST had superior images.  That is to say, 
they revealed details that the earth telecope did not reveal.  Like that the 
star was really a double not some sort of elongated blob as seen from earth.

This seems to me "science" at a meaningful level. It seems to me that the HST 
can make a really meaninful contribution even though the mirrors suffer from 
spherical abberation.  I say forge ahead.  BTW, as a Canadian it wasn't my tax 
money!

I say take pictures of all the things that they originally wanted to explore, 
and I betcha we will learn something from them.

Fred

  I think that the beef is that for 1.5 billion people wanted better than a 2X
increase in quality. That level does tell us about another "layer" of stars but
it doesn't answer questions as to how the universe began which some people feel
will happen with the advertised 10X increase in quality. Also, they may have 2X
anyway in a few years from ground based telescopes. 

  Personally I think that they have under estimated the size and age of the
universe and that what they will get is just 10 more layers of the same stuff
with no pictures of the "universe construction crew" driving away. But that's
just my semi-educated guess.

  Don't get me wrong, I'm real excited about those 10 layers but only because
I want to see the 10 layers, not because I think we will see the big bang.

  By the way, don't sell your self short up there in Canada. It was the 
Shuttle's Canadian arm that deployed the HST.

  George

                       Hubble Space Telescop Update
                             July 18, 1990
 
     During the last week, the Orbital Verification team continued with
tests to further characterize the spherical aberration and to refine
the telescope focus.  Specifically, the team has been working to
eliminate a slight coma and astigmatism from the optics.  A number of
diagnostic exposures were taken during the week with both the Wide Field
Planetary Camera (WFPC) and the Faint Object Camera (FOC) as part of the
process.  On July 15 the Faint Object Spectrograph (FOS) placed itself
into safemode. The verification team is studying the cause, and the
instrument is scheduled to be recovered from safemode as part of a series
of commands to be stored aboard the spacecraft and executed later this
week.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

                       Hubble Space Telescope Update
                                July 16, 1990
 
     The Wide Field Planetary Camera (WFPC) contamination (spots) have
disappeared as expected.  The big topics of discussion these past days have
been the frequent loss of lock in the Fine Guidance Sensors (FGS) and results
from the latest secondary mirror tilt and decentering.  Regarding the FGS
loss of lock, between July 11 and July 14 there have been numerous occurrences
of loss of lock in fine lock and acquisition failures.  Work over the weekend
may have turned up the cause of the problem (the wrong scale factors being
used in the FGS's).  The secondary mirror was moved in tilt and decenter on
July 12 and July 14.  The July 12 movement improved things, the July 14
movement made things worse.  There is now a strong feeling that there is a
sign error somewhere in the tilt or decenter software.  Finally, the latest
event of interest is that when the Faint Object Spectrograph (FOS) tested the
High Voltage (HV) relay that was felt caused the safing event last week, and
it produced another microprocessor reset and safed FOS again.
 
     The only news on the Pointing Control Subsystem (PCS) concerns the
abundance of FGS failures that have occurred since July 11.  FGS loss of
lock was becoming common place and not just occurring at the terminator,
failed acquisitions were also occurring.  This was producing a major impact
on daily operations and slowing the focus characterization by compromising
the Faint Object Camera (FOC) and WFPC images.  An apparent breakthrough
occurred over the weekend when it was discovered that 3 FGS scale factors
(constants used to specify FGS acquisition and lock) were not the expected
values.  The correct scale factors are now in the FGS's and all seems to be
working well so far.  The team that investigated the problem is convinced
that the scale factor error is the major part of the recent FGS problems but
they are not convinced that it is the whole problem.  Their study of the FGS
behavior is still underway.
 
     As of July 16 first phase of data taking in the focus characterization
was completed.  No new focus related FOC or WFPC images are scheduled to be
taken until July 23.  A number of new FOC and WFPC images have been taken,
these data are now under study.  The "biggest" news of the last few days were
the secondary mirror tilt and decenter movements.  On July 12 and 14 the
mirror was moved in tilt and decentered.  The result from the first movement
was an improved image, the second movement, however, produced a noticeably
worse image -- one with obvious coma.  This came as quite a surprise and
after much discussion it was concluded that there must be a sign error in one
segment of the software that controls the tilt and decenter movements.  A
quick look at the image degradation that the first tilt and decenter movement
a month or so ago produced seems to support the conclusions.  So, over the
next week there will be a major investigation of the mirror movement software.
The next 7 days have only Scientific Instrument (SI) activities so while there
will be much analysis of the image, and no new Wavefront Sensor (WFS) data or
mirror movements until July 23.
 
     The WFPC is in full operate mode, the latest round of focus support
images were finished.  SI testing should start shortly with the low
temperature decontamination.  The icing problem seen in the WFPC has
disappeared.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |



                       Hubble Space Telescope Update
                             July 20, 1990
 
     The entire week has been devoted to Scientific Instrument (SI)
performance and testing proposals.  The biggest event of the week
was a High Speed Photometer (HSP) safing on July 18.  Recovery from the
safing event is scheduled to begin on July 27.  Meanwhile, the Faint
Object Spectrograph (FOS) recovered from its safing event and ran Red side
proposals. The Faint Object Camera (FOC), the Goddard High Resolution
Spectrograph (GHRS), and the Wide Field Planetry Camera (WFPC) continue
to run a variety of instrument proposals without incident or anomaly.
FOS, FOC, and GHRS ran South Atlantic Anomaly (SAA) background measurements
this week with all finding better performance (i.e. lower counts) in the
SAA than expected.  The only bad news this week is that the Pointing
Control Subsystem (PCS) fix (the correction to the terminator induced
instability) has apparently run into trouble.  Look for a minimum of a one
to two week delay in the delivery and implementation of the fix.
 
     This week was a "good" PCS week until the news regarding the problems
with the terminator disturbance fix was announced.  While the Fixed Head
Star Tracker (FHST) and Fine Guidance Sensor (FGS) performance has been
excellent all week (i.e. very few failures), things are really not that rosy.
It does appear that the modifications introduced to FGS operations last
weekend are working well.  The dramatic drop in FGS failures from last weeks
toll is at least in part due to the lack of acquisition attempts.  Since the
SI intensive Science Mission Specifications (SMS) have been in progress since
July 16, there have been very few FGS acquisition attempts (no FGS acquisition
are scheduled this weekend).  Regular FGS use begins again on July 23 with
the beginning of the next Bootstrap focus characterization.  The FHST have
been performing well this week -- this may be premature but it does appear
that a reliable method is being worked out of use for these star trackers.
 
     All the SI's are appearing to be less sensitive to the SAA then expected.
This is excellent efficiency news.  Calibrations and even possibly some science
observations could be done during SAA passage, increasing the HST effective
efficiency.  The FOC has confirmed that their noise sensitivity to the SAA is
less than expected and has been running F/48 and F/96 internal exposures.
No anomalies have been reported.  The FOS recovered from safe (Blue side) and
conducted SAA noise measurements on the Red side.  As with the FOC they also
found that they were less sensitive to the SAA than expected (0.5
cts/sec/diode peak).  The GHRS has been running SAA noise measurements and
getting excellent maps of the SAA (and low counts).
 
     The WFPC completed their Low Temperature Decontamination proposal today,
and the result was a big bright spectrum in which there is a lot of excitement
over.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.aviation
Date: 18 Jul 90 21:35:03 GMT

	WASHINGTON (UPI) -- Secrecy imposed by the military limited NASA's
ability to oversee construction of the mirror that ultimately crippled
the Hubble Space Telescope, the space agency's former administrator
testified Wednesday.
	Because Perkin-Elmer Corp. of Danbury, Conn., also did classified
military work -- presumably involving optical systems for spy satellites
-- the Air Force limited the number of NASA employees in the plant where
the mirror was built, James Beggs told a Senate subcommittee hearing.
	``We had made an agreement with the Air Force to put a limited
number of people into that plant. ... The plain facts were that we did
not have the normal visibility that NASA (receives) in major programs,''
said Beggs, NASA administrator from 1981 through 1986.
	``(NASA only had) three or four people in the plant to oversee that
program at that period of time. That's far too few for a normal program.
But we were assured by a lot of different sources that adequate
oversight was present there and that we would be allowed to get a
visibility through the procedures that were in place,'' he said.
	But Beggs said the limitations made it ``awkward'' for NASA to
properly oversee the construction of the 94.5-inch mirror by
Perkin-Elmer, which is now Hughes Danbury Optical Systems Corp.
	``NASA was put in a position of not being able to oversee and have
the visibility into that program that it normally does,'' he said.
	The curvature of the mirror in the costly space telescope, ferried
into space in April, is off by about one-fiftieth the diameter of a
human hair, preventing it from bringing starlight to a sharp focus and
blurring the observatory's potentially revolutionary view of the
heavens.
	Like Hubble, advanced spy satellites also use large mirrors in
their optical systems and it is believed that Perkin-Elmer has played a
role in such projects in the past. Such programs are conducted in strict
secrecy.
	The $1.5 billion space telescope can still do about half of its
scientific work and will eventually be restored to full capacity by
replacing its instruments with more advanced models capable of
compensating for the mirror defect.
	But the blunder, coupled with other recent problems, has triggered
a storm of criticism of NASA.
	``I am embarrassed (and) distressed and no one is more disappointed
in what has happened on the Hubble than I because no one was looking
forward more eagerly to the results of this magnificent instrument than
I was,'' Beggs said.
	NASA must ultimately accept responsibility for the foul-up because
the agency oversaw the project, Beggs said.
	He said he visited the plant himself at one point to check the
progress and quality of the work because the program had experienced a
series of problems, including cost-overruns and delays.
	``One of the questions I asked is, `How are you going to test this
beautiful piece of equipment?' And I was assured by all of the experts
there that ... a proper test would done,'' he said. ``Everyone that
talked to me felt the tests were adequate to assure ourselves that the
telscope would work as advertised.''
	But Beggs acknowledged that at the time officials were more
concerned with making sure the mirror was smooth enough rather that
curved correctly.

From: [email protected] (Ron Baalke)

                            Hubble Space Telescope Update
                                    July 23, 1990

     This past weekend provided a rather uneventful finish to a week devoted
to running Scientific Instrument (SI) proposals.  The Wide Field/Planetary
Camera (WFPC) ran their low temperature decontamination proposal, a small
pointing problem was discovered during the test, but otherwise the test was
successful.  The Faint Object Spectrograph (FOS) continued mapping the South
Atlantic Anomaly (SAA) using the Red side (the Blue side is still in safemode).
The Goddard High Resolution Spectrograph (GHRS) ran their relative aperture
location proposal.  The Faint Object Camera (FOC) did a series of internal
"best focus" proposals on the F/48 and F/96 using the bright Earth as a light
source.  Results from these tests were satisfactory as far as the instrument
was concerned but the exposure intensities were found to be about 50 times
greater than expected.  At the moment the cause of this overexposure is
unknown.  The High Speed Photometer (HSP) sat quietly in safemode for the
weekend with its recovery due on July 27.  A retesting of the Pointing Control
Subsystem (PCS) fix ran smoothly and as expected; Lockheed now expects an
on-time delivery of the software.  A 4 day Bootstrap Science Mission
Specification (SMS) has begun.  This SMS contains the usual focus activities
plus a number of SI proposals.

     Good news on the PCS.  New reports from Lockheed are that the source of
the instability that occurred when they first tested the terminator
disturbance fix software has been identified and corrected.  Testing of the
corrected software went smoothly and has produced the expected results.
Delivery to the Goddard Space Flight Center (GSFC) of the package is expected
to be on or slightly ahead of schedule (i.e. within the next 10 days).  The
Fixed Head Star Tracker (FHST) performance has been exceptional -- in the
past 6 days there have been no FHST update failures.  Unfortunately, this is
due to luck and not to any change in operating procedures since how the
FHST's are operated has not changed in many weeks.  In the spirit of the
nature of the past weeks of HST events, it has been suggested that a special
investigatory committee be formed to examine why things are working so well
with the FHST's.  The Fine Guidance Sensors (FGS's) also did not experience
any failures over the weekend -- all observations were done on gyros, the FGS
were not used.

     The sign error in the decenter and tilt software has not yet been found.
The secondary mirror was decentered and tilted on the morning of July 23 with
the expectation that within the image the coma will be completely removed and
astigmatism reduced to a known level.   First pictures at the new setting are
planned for July 25.  Wavefront Sensor measurements (WFS 1, 2, & 3) are
planned for about 20 hours earlier.

     HST experienced it first solar eclipse on July 22.  Given that this total
eclipse was seen at very high latitudes on the Earth (mostly arctic regions)
the effect on HST was anticipated to be small.  A small drop (a few percent)
in the power from the solar arrays was seen during the few minutes of
penumbral passage.  The first "big" eclipse for HST is the summer 1991 solar
eclipse.

     FOC has obtained internal "best focus" data using the light from the
bright Earth.  All went well except that the count rate was significantly
higher (around a factor of 50) then expected.  The cause of the anomaly is
under investigation.  Next exposures are scheduled for July 25.

     FOS continued SAA noise measurements on the Red side (the Blue side is
still in safemode).  Peak counts were 1.2 counts/sec/diode -- well below any
health and safety concerns for the instrument.  The expectation is that the
FOS will be able to have its High Voltage (HV) on during SAA passage.

     GHRS ran its relative aperture location proposal over the weekend, all
went as expected.  Next activity for July 24 is  the detector stability
proposal.

     HSP is still in safemode.  Recovery is scheduled for the SMS beginning
on July 27 with proposals appearing in the July 31 or Aug 4 SMS.

     WFPC successfully completed their Low Temperature Decontamination
proposal.  All went well except for the pointing.  The desired star was
centered on the first chip, the offset that was issued to position the star
on the second chip placed it toward the edge of the chip, and the offsets
to place the star in the center of chips 3 and 4 put the it somewhere other
than on the two chips.  Needless to say these anomalous pointings are being
investigated.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)

                            Hubble News
                            July 26, 1990
 
     The seven-member team investigating the Hubble Space Telescope, led by
Lew Allen, director of NASA's Jet Propulsion Laboratory, took testimony in
secret yesterday.  The testimony was taken at the plant where the mirror was
made, at Hughes-Danbury Optical Systems Inc. (formerly Perkin Elmer), and
Allen was quoted as saying the group hoped to find a "smoking gun and a
fingerprint on the trigger."
 
     Evidence of a possible flaw in the Hubble Space Telescope was known back
in 1981 but scientists discounted tests that indicated a problem.  A NASA
board of inquiry has been sent to track down the cause of a problem with one
of the mirrors and that the investigation is looking into whether the 1981
test results pointed out the problem that now prevents the telescope from
being focused correctly in space.
 
     Officials of Hughes Danbury Optical Systems have declined to make any
comment because of the investigation now being conducted by NASA.  However, a
retired scientist for Perkin Elmer, the predecesor company to Hughes Danbury,
who was close to the Hubble project at that time in 1981, spoke of the
possible flaw. The scientist said that despite the possible flaw, the results
were assumed to be incorrect because they contradicted tests done with an
instrument they thought to be more accurate.  The scientist also said the
test results indicated that officials should have questioned the accuracy of
the test equipment at the time the tests were run.  He believed at the time
that additional testing was not necessary, but said that he and others were
working in a hurried atmosphere caused by delays and cost overruns, resulting
in pressure to finish the mirror.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)

               HST INVESTIGATION BOARD STATUS REPORT 2
 
     The Hubble Space Telescope (HST) Optical Systems Board of
Investigation met for the second time July 25 and 26, 1990, at
Hughes Danbury Optical Systems (HDOS), Danbury, Conn.
 
     Members of the Board interviewed current and former HDOS
(previously Perkin Elmer) employees involved in the design,
manufacture and test of the HST Optical Telescope Assembly (OTA)
primary and secondary mirrors.  The individuals interviewed provided
a great deal of information about this period in the development of
the HST.  The Board received data from engineering log books,
documentation of various contractor procedures and copies of results
from tests and analyses.
 
     Members of the Board visited the areas where the mirrors were
manufactured and tested and viewed the equipment used during these
processes, key items of which have remained intact since they were
used for the mirrors.
 
     Attention is being focused on the test equipment used during
the manufacture and test of the primary and secondary mirrors.  The
Board has defined measurements to be made of this equipment.  Due to
the fact that the equipment is just as it was during the period of
manufacture, the Board is optimistic that definitive results will be
obtained that will identify the source of the error.
 
     The Board discussed at length necessary elements for a test
program to yield information with sufficient certainty to be useful
in moving the investigation toward some conclusive findings.  In
upcoming weeks, procedures will be finalized and preparations will
be made to test various equipment, tools and reference devices used
for the OTA mirrors.  The Board will continue to study the
considerable volume of information it gathered during this meeting.
 
     In addition to previously appointed members of the Board, also
in attendance at this meeting was newly-appointed Robin Laurence of
the European Space Agency, who will be an observer to the Board.
 
     The next Board meeting has been tentatively scheduled for
August 15 and 16, 1990, at HDOS.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)

                          Hubble Space Telescope Update
                                 July 26, 1990
 
     Since July 23 most of the HST effort has been devoted to running the
Bootstrap Phase B, part 5j, Science Mission Specifications (SMS).  The
secondary mirror was tilted and decentered early on July 23 to reduce coma and
astigmatism in the system.  Wavefront sensor (WFS) measurements were obtained
on July 23 (WFS1) and July 24 (WFS2 and 3), and the Faint Object Camera (FOC)
and Wide Field/Planetary Camera (WFPC) diagnostic images were obtained on
July 25.  All the data is still in the analysis phase but preliminary results
of the WFS data suggest a significant reduction in both coma and astigmatism.
Visual inspection of the FOC and WFPC data appear to support at least the
absence of significant coma in the current image.  Interspersed amongst the
focus measurements were a small number of Scientific Instrument (SI) proposals.
All the SI proposals executed without problems or anomalies.  Fixed Head Star
Tracker (FHST) and Fine Guidance Sensors (FGS) performance has been great all
week.
 
     Nothing new on the Pointing Control Subsystem (PCS) system.  Initial
testing of the PCS fix is currently scheduled for the August 16 SMS.  FHST
performance has continued to be exceptional for the past 10 days.  FGS
performance has been equally good, with no failed acquisitions and only
infrequent loss of lock.
 
     Since the mirror movement good data has been obtained with WFS1, 2, & 3,
four diagnostic FOC images and ten WFPC images.  None of the analysis is
complete but the data from WFS1 and 3 suggest that all but a small amount of
coma has been removed and the astigmatism has been reduced by about half.
This is exactly what this tilt and decenter was supposed to do.  Image
analysis is getting underway.  There appears to still be a small dispute over
the sign of the spherical aberration.
 
     The Astrometry Team (AST) is supporting a variety of FGS and FHST
investigations.  A recent S-Curve FGS run uncovered a new double star
(separation about 0.2 arcseconds).  The AST team was pleased with this while
the Hughes Danbury Optical Systems (HDOS) team was distressed -- they must
now find another guide star.
 
     FOC successfully took more pictures in support of the focus
characterization.  They also reported that their instrument is better shielded
from the South Atlantic Anomaly (SAA) electrons than predicted.  It is
expected that there will be no "health and safety" SAA contour for the FOC.
The FOC is investigating cause of pointing errors (~3-6 arc seconds) between
where they should be pointing and where they actually end up pointing.  Part
of the error is certainly in the FOC (a systematic component) but part must
also arise somewhere else.  Nothing more on the very bright earth exposures.
 
     The Faint Object Spectrograph (FOS) ran only its Red side X-Pitch,
Y-Pitch, and (internal) Focus proposal.  The Blue side is still in hold from
the earlier safing event.  The expectation is that Blue side operation will
begin sometime next week.
 
     The Goddard High Resolution Spectrograph (GHRS) ran the High Voltage (HV)
stability proposal and found no significant differences from an earlier run.
The first GHRS spectrum (internal) will be produced tomorrow.
 
     The High Speed Photometer (HSP) is still in safemode.  Recovery is
scheduled for the SMS beginning on July 27, with proposals appearing after
August 4.
 
     WFPC successfully took its diagnostic exposures, check, and streak flats.
The cause of the pointing they found in the low temperature decontamination may
be due to an error in PASS software -- analysis is still in progress.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 10 Aug 90 06:18:08 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                  HUBBLE INVESTIGATION ADVISORY

Analyses of the possible causes of the observed spherical 
aberration in the HST suggest that the "reflective null 
corrector" may have been flawed.  The reflective null corrector 
is an optical reference device which was used to measure very 
precisely the surface figure of the HST primary mirror during its 
manufacture.  

The test setup incorporating the reflective null corrector 
remains essentially unchanged from when it was used in 
measurements during the final polishing and coating of the 
primary mirror in 1981.

The HST project/contractor team, led by Dr. Lew Allen, Chairman 
of the HST Optical Systems Board of Investigation, has been 
concentrating its efforts looking for an error in the reflective 
null corrector.  Over the last two weeks tests have been run, 
systematically checking various aspects of this device. 

Preliminary results of a test conducted at HDOS yesterday and 
last night to look at the spacings of the elements in the 
corrector have revealed a clear discrepancy of approximately 
1 millimeter between the design of the null corrector and the 
device as it exists.  One millimeter is about 1/25 of an inch 
(about the diameter of the point of a ball-point pen).  
Preliminary analysis indicates that a discrepancy of this 
magnitude could cause spherical aberration similar to that 
observed in the HST primary mirror.

The investigation board will now concentrate its efforts in two 
areas:  refining the measurement of the observed reflective null 
corrector spacing discrepancy and continuing to examine all 
aspects of the reflective null corrector and associated test 
apparatus as they were constructed and used in the fabrication of 
the primary mirror.  The board is scheduled to meet at HDOS on 
August 15 and 16, 1990.  This meeting will be the first 
opportunity for the full board to review the test procedures and 
resulting data.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (John Roberts)
Newsgroups: sci.space
Date: 11 Aug 90 01:32:15 GMT
Organization: National Institute of Standards and Technology

HUBBLE STATUS REPORT - Teleconference (audio only)  8/7/90 4:00 P.M.

The following is a set of notes from the report on NASA Select. I may of
course have misinterpreted some of what was said. This is the group which
is primarily concerned with measuring the error and finding a hardware fix
so WFPC2 can be completed and installed in a timely manner.
.........................................................................

 - Some of the investigation involves testing of the many components of HST
to make sure they work. A recent test involved ~100 exposures using the
WFPC and various filters.

 - Several instruments which were thought to be susceptible to the radiation
of the South Atlantic Anomaly have turned out to be less sensitive than had
been expected. This is good news, because it means that they will be usable
further into the SAA than had been planned, and some may be usable throughout.

 - They think they have a software fix for the safing problem associated with
turning on the "blue side" of the Faint Object Spectrograph (FOS). If it's
only an infrequent problem, this should be fine.

 - The High Speed Photometer (HSP) has five detectors, including one
photomultiplier tube. Recently the tube was turned on for testing, and it
seems to work.

 - The Goddard High Resolution Spectrograph (GHRS) has successfully been 
employed in a spiral scan operation. In this mode, the GHRS issues instructions
to the command and data handler which causes HST to slowly rotate in order to
perform a scan of a small segment of the sky in a spiral pattern. This is used
to create images (and a mosaic can be built up using multiple spiral scans),
and to locate interesting targets for more detailed investigation. This test
is significant because it represents the first time HST has fully controlled
its motions itself (rather than by direct commands from the ground). Eventually,
onboard target acquisition will be used extensively.

 - There have been several mirror characterization adjustments, as a prelude
to placing the mirror in a fixed position for the next three years. They think
they now understand the control of the secondary mirror, and will be able to
get it into a good position. More work is planned for the following few days.

 - The initial goal is to obtain a coarse measure (95% accuracy) of the
corrective prescription needed, by Labor Day. Work seems to be well ahead of
schedule. Two test procedures are to be used: "wide sweep" and "mini sweep".
Wide sweep involves moving the mirrors far out of focus in both directions.
For mini sweep, the focus is changed micron by micron. Numerous exposures are
taken, and analyzed by computer to characterize the aberration. Once the
initial number is available, it will be sent to the vendors, so they can
start rough grinding of the nickel-sized corrective mirrors for WFPC2.

 - Further measurements will be made starting in September and October
(interspersed with science activities), with the goal of refining the
accuracy of the prescription from 95% to 99% or 99.5%. The more refined
number is needed by November or early December, so the vendors can complete
final polishing sometime in the winter.

 - The first science activities will be intended not to obtain new scientific
knowledge, but to determine how well the instruments work for scientific
research. Targeted are the Wide Field/Planetary Camera (WFPC), and the
Faint Object Camera (FOC).

Comments from question and answer period:

 - It is not clear that all the remaining coma has been removed by tilt and
decenter motions of the secondary mirror, but they are fairly sure that this
will be accomplished within a week. There is still a high level of confidence
that all of the error is in a spherical aberration of the primary mirror.

 - It was commented that immediate announcement of the discovery of the
aberration (and its implications) to the press was probably a mistake. 
If they had waited 3-4 days until they understood the situation a little
better and had had a chance to think about it, many of the irresponsible
statements that are still circulating in news stories could have been avoided.
[If they had done this, I don't think it would have qualified as a coverup.
It had already been announced the day before that there was an investigation
into a possible aberration. They could have just extended this review a few
days, and said "we'll make an announcement when we understand it".]
Example: it was initially announced that WFPC and FOC were essentially useless.
It is now thought that they will have considerable use in their present form,
possibly 10-20% of what had been expected. While disappointing, that's a lot
better than 0%.

 - They are trying to decide how accurate the correction needs to be. Beyond
a certain point, the optics will be essentially within spec, and there are
diminishing marginal returns. They don't want to take up weeks of telescope
time that could be used for science to get an imperceptible improvement.

 - It's been about a month since the software fix was installed to continually
update the memory in the fine guidance electronics that was getting zapped
by the SAA. There have been no further problems, so it seems to be OK.

 - Until the hardware replacement, the GHRS and FOS are expected to be the
most useful instruments. Both seem to work fine, which makes the space
scientists happy.

 - There is still considerable interest among the general users in experiments
involving the WFPC and FOC in their present state.

 - Tentative schedule:
   - Aug 92: delivery of WFPC to Goddard for testing (perhaps as early as 
      June 92)
   - Goddard is trying to find ways to streamline the testing and still do
      a good job. They're aiming for 6-9 months.
   - June delivery > January launch
     August delivery > May launch
     The specification is for launch no later than May or June 1993. They're
     shooting for January 1993. They'll know more about the details in 6-7
     months.

 - (Why are the prescription and the correcting mirrors needed so soon?)
   WFPC2 has actually been in development for 3-4 years. In fact, the optical
   section with the nickel-sized mirrors has already been completed. This
   section will have to be disassembled and the corrected mirrors replaced.
   Like all complex instruments, WFPC2 has to be assembled in a specific
   sequence, so if the mirrors are late, it will hold up assembly of the
   other parts of the camera.

 - WFPC2 will not be launched until it has undergone an "end-to-end" test.
   To do this, they will use a light beam which has been subjected to the
   same spherical aberration calculated for the primary optics (to the 
   accuracy needed) to make sure that the correction works. The instrument
   will be tested at JPL before shipment to Goddard.

 - To verify that the prescription is correct, there will be three or four
independent analyses of the observed data.

 - The goal is to get the optics to or extremely close to spec, which is
70% of the light energy from each point source falling within a 0.1 arc second
circle.

 - The corrective software for the day-night wobble has been written, and is
being tested. The testing isn't going as well as anticipated, so it probably
will not be delivered until the end of September. It is important that the
software be thoroughly tested and verified before installation, because it
implements a major function that wasn't originally intended for HST. There is
a risk of "glitches" in which the new function interferes with functions
already present. Simulation of the physical parameters indicates that the
fix will work once it is properly implemented.

 - The first priority for this group right now is to get the best possible
prescription as soon as possible to facilitate construction of WFPC2. Later,
concentration will shift toward optimizing ongoing science, i.e. by 
computational image reconstruction. Currently, many of the image analysis
people are busy with the prescription effort.

 - The next HST teleconference is scheduled for Tuesday, August 14, at 4:00 PM
EDT.

Comments:

 - There are still conflicting reports in the media that the backup mirror
was/wasn't completed. It seems to me that if it had been completed, somebody
would be talking about testing it in the Perkin Elmer test rig to see what
happens.

- A space science idea: I get the impression that most of the scheduled 
experiments are directed toward specific targets. It might be interesting
to pick a few points in space completely at random, and see what's there. :-)
 
        John Roberts
        [email protected]

Date: 14 Aug 90 04:02:33 GMT
From: [email protected]  (Peter E. Yee)
Subject: HST takes family portrait of stars outside Milky Way (Forwarded)
 
Paula Cleggett-Haleim
Headquarters, Washington, D.C.	August 13, 1990
(Phone:  202/453-1547)
 
Randee Exler
Goddard Space Flight Center, Greenbelt, Md.
(Phone  301/286-7277) 
 
    RELEASE:  90-111
 
    HST TAKES FAMILY PORTRAIT OF STARS OUTSIDE MILKY WAY
  
	After only preliminary analysis, NASA'S Hubble Space Telescope
(HST) has provided the first detailed views of how massive stars are
formed in galaxies unlike our own.  Early observations, in support of
an engineering test, of 30 Doradus, the most prolific stellar nursery
within the Large Magellanic Cloud, revealed new information about our
neighboring galaxy. 
 
	"To have important science unexpectedly arise from engineering
test data came as a pleasant surprise to the HST science team," says
Dr. Edward Weiler, HST program scientist. 
 
	Hundreds of stars are believed to exist in this region, which
is smaller than from here to the nearest star, about 4 light years
away. One can easily count 60 stars just with the naked eye.  Early
computer analyses of this same image suggest that HST may be resolving
many more stars.  This region was thought to consist of a single star
as recently as just 10 years ago. 
 
	NASA now has a unique and detailed view of massive stars in
the neighborhoods of their birth.  Dr. Sally Heap, a NASA
astrophysicist remarked, "We now have the finest family portrait of
stars outside our galaxy." 
 
	Dr. Charles Pellerin, Director of NASA's Astrophysics
Division, said, "This now demonstrates HST's ability to conduct
crucial and important studies, even with the existing spherical
aberration.  We will continue to study this region over the next few
months, and the best is yet to come." 
 
	HST scientists plan the following activities:
 
	--to use imagery, with the "planetary camera" mode of the Wide 	
	Field/Planetary Camera (WF/PC) and the European Space 	
	Agency's Faint Object Camera (FOC) to gain another factor 
	of at least two in clarity (the current image  was taken in the 	
	"wide field" mode).
 
	--to use longer exposure times to image the fainter stars and make
	signal processing easier
 
	-- this image of 30 Doradus was acquired with an exposure of only
	40 seconds.
 
	--to produce "color imagery" by using filters to image this region
	in the near ultraviolet, green, yellow, and near infrared; the
	current image was taken in one color, violet.
 
	--to use spectroscopy to infer the temperatures, masses and chemical
	composition on many of the brightest stars, individually.
 
	The HST photograph of 30 Doradus was made on Aug. 3, 1990,
with the Wide Field/Planetary Camera (WF/PC) for use as a finding
chart in the checkout of another HST instrument, the Goddard High
Resolution Spectrograph.  The WF/PC produces star images with sharp
cores, 0.1 arc-seconds wide.  This image quality is sustained over the
full field of view, which is 2.7 arc-minutes square. 
 
	30 Doradus is readily visible with the naked eye from the
Southern Hemisphere of Earth, although it is located in another
galaxy, the Large Magellanic Cloud, at a distance of about 160,000
light years from Earth.  The late American astronomer Harlow Shapley
stated that 30 Doradus is so bright that if it were put in place of
the nearby Orion Nebula, it would cast shadows on the nighttime
landscape of Earth.  30 Doradus is located in the constellation
Dorado, the Swordfish. 
 
	HST astronomers studying the WF/PC picture report that they
can make out the central stars of the R136 cluster, within the 30
Doradus nebula. They note that because the picture was taken in violet
light, at a wavelength of 3680 angstroms, it brings out the hottest,
most massive stars in the picture. 
 
	Hot stars produce more blue and ultraviolet light than cooler
stars. Several of the stars appear to be single objects at the
resolution of the WF/PC picture.  Given their brightness and the
distance to 30 Doradus, this observation strengthens the possibility
that they may be more than 100 times as massive as the Sun. 
 
	Every HST picture of star clusters should achieve the
resolution demonstrated in the photograph of 30 Doradus.  Such
photographs, when obtained through the different colored filters on
the WF/PC and the Faint Object Camera (FOC), are expected to provide
detailed information on the masses of stars in the clusters. 
 
	Then, knowing the mixtures of masses in a cluster (i.e., how
many stars of each mass are present), astrophysicists can deduce basic
information on how stars form and how they produce the chemical
elements present in space.  All massive stars probably become
supernovae, spewing out their newly made elements.  These elements,
especially iron are essential ingredients to life on Earth.  By
determining how many such stars are present in 30 Doradus and similar
star clusters in more distant galaxies, astronomers expect to deduce
more accurate information on the enrichment of chemical elements in
the Universe. 
 

                  HST INVESTIGATION BOARD STATUS REPORT
                         August 16, 1990
 
The Hubble Space Telescope (HST) Optical Systems Board of Investigation,
met Wednesday and Thursday at Hughes Danbury Optical Systems, Danbury, CT.
The board concluded that the previously reported spacing error in the
reflective null corrector -- an optical reference device used to
measure the surface of the HST primary mirror during its
manufacture -- is the cause of the spherical aberration, according
to Dr. Lew Allen, Chairman of the HST Optical Systems Board.  The
board has not yet been able to determine how such an error
occurred; this question will be examined over the next several
weeks as documentation can be located and reviewed.  The board will
continue to probe the details of the testing and certification
process.  The next meeting is scheduled for September 12 and 13 in
Danbury.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected]
Newsgroups: clari.tw.space,clari.news.gov.usa,clari.tw.electronics
Date: 19 Aug 90 18:55:23 GMT

	DANBURY, Conn. (UPI) -- The company that made the Hubble Space
Telescope's mirrors ignored its top scientist's call for more testing, a
call that could have detected the mirrors' flaw, a published report said
Sunday.
	An error in a ``null corrector'' led technicians in the optical
systems division of the Perkin-Elmer Corp. to grind the Hubble's main
mirror into a shape that now keeps the $1.5 billion telescope from
focusing, NASA officials said last week.
	The Hartford Courant, which Sunday published a Hubble story that
included interviews with the former top scientist and other scientists,
said that the testing program at Perkin-Elmer was limited from the start
and was further undermined by pressures created by cost overruns and
missed deadlines.
	The problem could have been caused by something as simple as a
misplaced washer in the null corrector, a NASA panel said last week at
Hughes-Danbury Optical Systems, which took over the Perkin-Elmer
division in December.
	Roderic M. Scott, 75, told the Courant that he retired as the
division's chief scientist a year early in 1980 while the telescope's
mirrors were still being manufactured, partly because the company would
not heed his warnings.
	``I said, `Let's take a week and do an independent test,''' Scott
said. ``I was stirring the pot, trying to get them to do more tests.''
	Scott said he did not suspect anything was wrong with the Hubble
but felt that more testing should have been done as insurance.
	At least two other scientists who worked on the telescope said they
also had pressed for additional testing.
	The shaping problem in the orbiting telescope's 94.5-inch main
mirror was discovered in last June.
	Perkin-Elmer conducted tests in April 1981, but they did not
include measuring the space between the null corrector's mirrors and its
lens, three people involved in the project told the Courant.
	Scientists had originally planned to conduct a complete test of the
null corrector when the mirror polishing was finished, but Perkin-Elmer
officials abandoned the idea to save time and money, the three said.
	``The final check should have been done. There is no two ways about
it,'' said a former Perkin-Elmer scientist.
	At that time, Perkin-Elmer was under pressure to complete the
primary mirror so it could give more attention to the telescope's
12-inch secondary mirror and its guidance system, which were behind
schedule, said John D. Mangus, a member of the NASA board investigating
the flawed mirror.
	A list of work was submitted for testing the primary mirror's null
corrector, the former scientist said.
	``The decision was, because of money and time, it would not be
done,'' the scientist said.
	``At that point in time, everything was so tight-fisted, they were
shutting all the programs down. As quick as they looked finished -- bang
-- they were shut off,'' he said.

    I notice that the news media are still making the HST problem sound
    totally catastrophic, claiming that it is "prevented from focusing" by
    the aberration problem.
    
    Perhaps someone independent of NASA should write a letter to a
    prominent newspaper to point out that the telescope CAN focus AND take
    clearer pictures than Earth-based telescopes, even with the aberration
    present.
    
    All of this ultra-negative reporting of the problem does nothing to
    help NASA to provide future solutions to fix it.
    
    
    Dave Hazel

There has finally started to be a bit of reporting of the good news, like
the latest discovery via WF/PC that a star group which was recently thought
to be 7 or 8 stars is really 60 or so.  Unfortunately, these articles tend
to begin, "Embattled NASA, trying to shine up its tarnished image, released
the following info today..."

Burns

  The criticism is that the billion + was too much for a telescope that's only
about 2 times better than what we have on earth. Especially considering how
much the thing was over sold. No one gives a rip about a few more stars, the
dam thing was suppose to show us creation itself.

  Well, some of us like the extra stars but at one point they were telling
us that it would have an increased resolution of 350. Then it was down to
10. Now it's maybe 2 because someone forgot to see if the mirror was cut
right.

  They screwed up. They'll straighten it out in '93 but it was a blunder.

  George

    Re. -.1
    
    I am sure I have seen a figure quoted somewhere recently giving the
    resolution of the HST as 0.1 arcsec, even with the aberration. This is
    a factor of 10 better than the usual Earth-based limit of around 1
    arcsec, which is limited by atmospheric turbulence.
    
    When NASA constantly has to contend with this kind of attitude of
    "these guys can't do things right, so let's stop giving them any
    money", it is hardly surprising that they try to cut costs whenever
    possible. To the minds of the beaurocrats who run this kind of
    organisation these days, such an approach seems quite logical.
    
    Dave Hazel

                        Hubble Space Telescope Update
                               August 3, 1990
 
      Scientific Instrumet (SI) highlights this week were an Astrometry full
aperture lock test, Faint Object Spectrograph (FOS) Red Side fine Y-base
stability and Blue Side High Voltage (HV) relay testing, and the Goddard
High Resolution Spectrograph (GHRS) Mode II Spiral Search ("first light" for
GHRS).  The Astrometry test ran well with FGS3 yielding excellent S-curve
data but FGS1 and 2 gave significantly less than optimal S-curves.  The
initial suggestion of a cause of the poor modulation of the image seen in
Fine Guidance Sensor (FGS) 1 and 2 is that coma and astigmatism are
effecting these FGS's more than FGS3.  The most interesting result from the
FOS testing this week is that they detected a drift in the location of their
spectrum -- suggesting a possible sensitivity to the magnetic field of the
earth within the instrument.  Also, testing of the FOS Blue side relay that
caused the safing failed to produce any problem.  GHRS successfully saw first
light, stars in the 30 Dor region of the LMC, in their camera mode (i.e. no
spectrum).  Some operational problems occurred during the execution of the
proposal (FGS loss of lock) but enough data was obtained to call it a
successful first light.  On August 4 the first of two Bootstrap SMS will
begin that will start the full characterization of the Optical Telescope
Assembly (OTA).  These first two SMS's will run for 8 days, finishing early
on August 12.
 
     The HST Pointing Control Subsystem (PCS) has been exhibiting some
problems this past week, all old problems though, no new problems.   Small
fixes made to the Fixed Head Star Tracker (FHST) operation software have
been improving the reliability of the FHST updates.  We still are suffering
from some failures due to edge of the field-of-view effects and "spoiler"
stars.  Some progress is being made, however.  The FGS's have been exhibiting
a problem for a while that may develop into a significant operational
difficulty. The FGS Photomultiplier Tube (PMT) appear to be sensitive to the
South Atlantic Anomaly (SAA).  Upon entering the SAA the background level
rises equalling the counts produced by a ~13th magnitude star.  This makes
acquisition of such a star during an SAA passage difficult at best.  It also
increases the probability of loss of lock during SAA passage.  Data is now
being collected to fully examine the interaction of the FGS's with the SAA
and make recommendations for normal operations.  A meeting on August 5 will
discuss how to handle this problem in the short term.  The terminator
disturbance fix software has a mid-August delivery date to Goddard Space
Flight Center (GSFC).  With ground testing and check out look for testing on
the spacecraft around the last week in August.  The pointing problems
experienced by the Wide Field/Planetary Camer (WFPC) and Faint Object Camera
(FOC) appear to be problems in the generation of the slew eigenvalues in PASS.
A software fix is currently being tested.
 
     Analysis of the FOC F/96 UV and F/288 visual images obtained on July 27
show that the UV images look very much like the optical images: a sharp core
with a big halo.  Encircled energy curves are very similar to that derived
from optical images.  Some coma is clearly seen in the UV images (probably
due to the residual coma known to still be in the optics).  The F/288 visual
image shows coma and astigmatism but at a level expected from the current
state of the OTA.  The only other news regarding the focus of the HST is
that it appears that the image characterization effort will be more extensive
than originally planned.  Various panels and advisory groups have been making
recommendations on desirable ways to proceed, these recommendations are being
convolved with physical and operational constraints to develop a comprehensive
characterization program.  Various aspects of this program, including
obtaining test scientific data, will continue for ~2 or 3 months.
 
     The White Sands receiving station for TDRSS has been experiencing a lot
of problems of late (data drop outs, loss of signal, and the such), with HST
and other spacecraft.  They have temporarily imposed a hardware/software freeze
to isolate and investigate their problems.
 
     FOS ran more Red side tests and exercised the Blue side relay that caused
their most recent safing events.  They found that their Y-base spectral
position was lower than expected and that there is an apparent drift of the
location of the spectrum on the diodes over the HST orbit.  Extensive testing
(24 cycles) of the Blue side HV relay failed to show a problem -- it is now
operating as it should.
 
     GHRS obtained its first light yesterday (see above): Proposal 1350 --
Mode II Spiral Search.  A 5 x 5 spiral map was made, 3 stars were detected.
The images were clearly asymmetric.  The data is still under study.  The GHRS
had some problems with FGS loss of lock and lost most of the second half of
the proposal.
 
     The High Speed Photometer (HSP) is in hold awaiting their first proposal
since their safing event.  WFPC successfully took its check flats and
supported the GHRS spiral search with an image of the 30 Dor region.  The WFPC
high temperature decontamination went quite well, before and after results
equaled or exceeded expectations.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

                         Hubble Space Telescope Update
                                August 10, 1990
 
     The biggest news
is that the Allen Committee issued a press release yesterday indicating that
they may have identified how spherical aberration was introduced into HST.
Examination of the reflective null corrector used to check the primary mirror
uncovered a possible manufacturing error: the spacing between two elements
appears to be in error by ~1 mm, if this spacing error is confirmed it would
produce spherical aberration consistent with that observed in HST.  The
corrector is now under intensive study, more definitive results are expected in
the future (probably weeks).  The findings of the Allen Committee have caused a
major revision of the HST August/September schedule.  The extensive image
characterization proposals scheduled to begin in a week have been deferred
until later.  The characterization proposals will be replaced by an "Early
Release Observation" (ERO) program and an "Initial Science Assessment" (ISA)
program.  The ERO and ISA programs are designed to take sample real scientific
data (i.e. data on scientifically interesting objects) to assess the true
scientific capabilities of all the Scientific Instruments (SI) on HST.
Initial ERO and ISA programs
will start on August 16, the specific schedule of observation is, at the
moment, tentative (the decision to advance the ERO and ISA programs and defer
the characterization tests was made late yesterday).  Finally, one piece of bad
news arrived this week -- on August 6 it was announced that the PCS fix
software
has encountered additional problems and that a 1 month slip in delivery is
anticipated.  Assuming the current schedule look for this software to arrive at
Goddard Space Flight Center (GSFC) in mid-September with full installation in
the spacecraft in early October.
 
     The Fine Guidance Sensor (FGS)
sensitivity to the South Atlantic Anomaly (SAA) problem has
has already developed into a significant operational difficulty -- causing the
failure of a few FGS acquisition attempts and the loss of data.  The most
significant loss was 4 out of 6 FGS S-curve measurements yesterday.  Meetings
are in progress to formulate a short termed and long termed solution.
 
     Most of the news concerning focusing has come out of the Allen Committee
investigation.  Of
most interest is the possible discovery of an incorrect spacing between
elements of the reflective null corrector used to test the primary mirror.  The
Allen Committee press release states that they found a ~1 mm discrepancy in the
spacing of the elements of the corrector and that this is of the correct order
of magnitude to produce the spherical aberration seen in HST.
Examination of the
reflective corrector turned up a 1.3 plus/minus 0.5 mm discrep?ncy in the
spacing of the elements in the corrector.  The claim is that a ~1.1 mm
discrepancy in the corrector would induce 0.5 wave of spherical aberration.
Over the next weeks the corrector will be examined carefully and in great
detail, the expectation is that the separation should be determined to an
accuracy of some number of microns.  Also, the "inverse null corrector" that
was used to check the stability of the null corrector during testing apparently
still exists and can be used to check for any changes that may have occurred in
the years since it was last used.  All of this is "new" information (a day or
two old) so expect things to change a little over the next week.  On other
fronts, the last wavefront sensor (WFS) data for a while has been taken.  All
parties involved have agreed that while the WFS's are now giving very
consistent data, the interpretation of the data, and what it suggests about the
optical system is ambiguous at best.  Hughes-Danbury Optical Systems (HDOS) has
gathered a good quantity of high quality WFS data over the past weeks and are
now going to intensively study the data to see if anything can be done to
improve the analysis.  Over the past week there have been a number of focus,
tilt, and decenter secondary mirror movements designed to remove the residual
coma and astigmatism.  Overall both aberrations seem to have been reduced from
what they were a week ago but analysis of the latest images by HDOS (images
taken yesterday using the Faint Object Camera (FOC)) is not complete; a report
is expected from HDOS
tomorrow.  On August 12 a "mini-sweep" focus run begins: moving the mirror
over a
range of focus positions, with FOC and WFPC images at each position, to
establish a preliminary "best focus" for the ERO and ISA program.
 
 
     FOC ran a series diagnostic exposures for HDOS but otherwise had a quiet
week. The Faint Object Spectrograph (FOS) ran more Red side tests (Discriminator
Optimization and SAA Noise).
 
     The Goddard High Resolution Spectrograph (GHRS) ran Spectral Cal Lamp
proposals.  On August 13 there should be a press
conference showing the WFPC image of the 30 Dor region of the LMC obtained
while they were supporting GHRS.
 
     The High Speed Photometer (HSP) ran their Photomultiplier Tube
(PMT) test with no anomalies, the
PMT appears to be working fine.  WFPC successfully took flats and diagnostic
exposures with no significant
anomalies.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

                          Hubble Space Telescope Update
                                 August 13, 1990
 
     This past weekend was nicely quiet at HST.  The only "big" news was some
very unofficial news regarding the Pointing Control Subsystem (PCS) terminator
jitter fix.  Apparently, the problem that was responsible for the 1 month
delay has been identified and fixed.  The expectation is that the new control
software will be delivered much earlier than the official 15 September
delivery date, although the official delivery date is unchanged.  The near term
HST schedule is still not fully formed but Early Release Observations (ERO)
and Initial Science Assessment (ISA) observations will begin on August 16
and the image characterization proposals originally scheduled to begin on
August 16 have been deferred until later.  The only other news comes from the
Wide Field/Planetary Camera (WFPC) image of 30 Dor that was taken for the
Goddard High Resolution Spectrograph (GHRS) team on August 3.  Analysis of
this image by the GHRS and WFPC teams and Space Telescope Science Institute
(STScI) staff show the R136a region to be resolved into a large number (> 50)
of stars.
 
     There were 2 Fine Guidance Sensors (FGS) failures on August 12 that were
caused by the limb of the bright earth.  The failures are under study, the
expectation is that the bright earth avoidance angle will be increased.  The
slewing error (effecting WFPC and Faint Object Camera (FOC) relative slews)
that was found in PASS a week or so ago has been found, corrected, and tested.
Installation is expected in the 16 August ERO/ISA Science Mission Specification
(SMS).
 
     Nothing new in HST focusing other than the rearrangement of the HST
schedule and the resulting delay in the image characterization proposals.  On
August 12 a "mini-sweep" focus run was begun that moves the mirror over a small
range of focus positions, with FOC and WFPC images and Astrometry transfer scans
at each position.  The purpose of this proposal is to set a "best focus" for
the ERO and ISA program.  So far all is going adequately well: FGS loss of lock
induced by the bright earth limb has caused the loss of some Astrometry
transfer scans.  A firm date for the rescheduling of the image characterization
has not yet been established but the working date for the start of the
characterization run is August 30.  Analysis of the FOC images by Hughes
Danbury Optical Systems (HDOS) showed that most of the coma and astigmatism
has apparently been removed.
 
    The August 16 SMS has as candidate observations for ERO and ISA program:
FOC images of a radio galaxy with a jet, FOC observations of the QSO AP Lib
looking for fuzz, WFPC images of NGC 1850 in the LMC, the normal galaxy
NGC 7457.  There is also a crowded field photometry proposal by WFPC and a
WFPC PSF test in NGC 188.
 
     The Astrometry Team (AST) has reported that their analysis of the FGS
S-curve data taken this week show that FGS2 is giving the poorest S-curves.
 
      FOC is taking a series exposures in support of the current focus run.
The Faint Object Spectrograph (FOS) reported that their Red side "drift"
is indeed well correlated with the transverse magnetic field.  The
peak-to-peak amplitude is ~50 microns.  This will require additional
processing of FOS data.  Red side dark count testing showed all was as
expected. FOS has no scheduled activities for the next 6 days.
 
     GHRS is in hold and has no planned activities for about 9 days. Results
from their press conference on the WFPC image of the 30 Dor region of the LMC
was discussed above.  A threshold adjustment proposal was run, all went fine.
 
     WFPC is in the process of supporting the focus activities, first images
are scheduled to be taken this evening.  Over the weekend WFPC ran more flats.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    The HST folks released two new images yesterday.
    
    One was of a nearby 'boring' galaxy (sorry, but I forgot the NCG
    number) as a test of WF/PC and revealed the core to be much denser than
    was expected, in excess of 30,000 stars in a 9 LY radius. This makes it
    second only to M32 in terms of observed density at galactic center
    which means it may (repeat MAY) be candidate for a black hole.
    
    The other was an FOC image of supernova 1987A which quite spectacular,
    with a ring of glowing matter surrounding the star that is not a
    remnant of the explosion; the shock wave would not have reached that
    far. The ring effect is believed to have been created by the star's
    evolution from red supergiant to blue supergiant over the last million
    years.
    
    The will be a science writers' seminar on Sept 19 at STI were they will
    release other images and discuss results so far.
    
    gary

From: [email protected] (Ron Baalke)
Date: 29 Aug 90 17:21:39 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

HUBBLE SPACE TELESCOPE PEERS INTO CORE OF DISTANT GALAXY
 
     NASA's Hubble Space Telescope, a cooperative program with 
the European Space Agency, has provided a remarkably new detailed 
view of the core of a galaxy which lies 40 million light-years 
away, more than half way to the great Virgo cluster of 
galaxies.  These results promise that astronomers will be able to 
use the Hubble Space Telescope to probe the mysterious centers of 
galaxies, in a search for massive black holes.
 
     The image, taken with the Wide Field and Planetary Camera on 
August 17, reveals that stars are much more tightly concentrated 
at the center of the galaxy than was previously expected.  Since 
the galaxy, cataloged as NGC 7457, is assumed to be a "typical" 
galaxy, these preliminary findings suggest that the nuclei of 
normal galaxies may be more densely packed with stars than 
previously thought.
 
     HST scientists are greatly encouraged by this new 
observation and emphasize that it demonstrates intriguing science 
can be routinely accomplished with the spaceborne observatory.  
"The images of NGC 7457 show emphatically that research on nuclei 
of galaxies can still be done", says Tod Lauer, of the Wide Field
and Planetary Camera imaging team.  "We've never been able to
study any galaxy outside of our Local Group, our "neighborhood"
of about two dozen galaxies, at this resolution before," he said.
 
     The centers of galaxies are extremely interesting to 
astronomers because the centers are at the heart of the violent 
processes that give rise to cosmic jets, quasars, Seyfert 
galaxies and other mysterious energetic behavior.
 
     NGC 7457 is a quiescent galaxy picked for its "normality" as 
an early target for assessing the science performance of HST.  
The resulting images show, to the surprise of astronomers, that 
an exceptionally bright and compact core is embedded in the 
diffuse background of the rest of the galaxy.  Based on this new 
image, the stars in the nucleus of NGC 7457 are crowded together 
at least 30,000 times more densely than those stars seen within 
our own galactic neighborhood.  This extraordinarily high stellar 
density exceeds earlier estimates from ground-based observation 
of NGC 7457 by a factor of 400.
 
     It is far from clear whether or not a massive black hole is 
at the center of NGC 7457, since the images alone do not provide 
the answer.  But these new data suggest that NGC 7457 is an 
excellent place to use the HST's spectrographs to measure how 
much mass is concentrated at the center of the galaxy.
 
     The Space Telescope Science Institute is operated by the
Association of Universities for Research in Astronomy, Inc., for
NASA, under contract with the Goddard Space Flight Center,
Greenbelt, Md.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 29 Aug 90 17:19:53 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

HUBBLE SPACE TELESCOPE RESOLVES GASEOUS RING AROUND SUPERNOVA
 
     NASA's Hubble Space Telescope, a cooperative program with 
the European Space Agency, has provided a dramatic new look at 
the remnants of one of the most spectacular and unexpected 
astronomical events of this century, the great supernova of 1987.
 
     Observations made with the European Space Agency's Faint 
Object Camera, on August 23-24, have provided, with unprecedented 
sharpness and clarity down to .1 arc second, an intriguing view 
of the supernova and its surrounding shell of stellar material.  
The image, taken in visible light, reveals the details of the 
circumstellar shell, whose characteristics previously had been 
suggested by ground based observations and data from the 
International Ultraviolet Explorer satellite.
 
     This new image will provide important insights into the 
evolution of massive stars and their catastrophic deaths as 
supernova explosions.
 
     The visible light image clearly shows an elliptical, 
luminescent ring of gas about 1.3 light-years across surrounding 
the still glowing center of the 1987 explosion.  The ring is a
relic of the hydrogen-rich stellar envelope that was ejected in
the form of a gentle "stellar wind" by the progenitor, which was
a red supergiant star that existed an estimated 10,000 years
before the explosion took place.
 
     This diffuse gas was subsequently swept and compressed into 
a narrow, high-density shell by a high-speed stellar wind ejected 
from the star when it evolved back to a blue supergiant stage.  
The image suggests that the star was more efficient at 
compressing gas along an equatorial plane, to create a ring-like 
structure.  Because the ring is inclined along the line-of-sight, 
it has an elliptical appearance.
 
     In the first few hours following the supernova blast the 
ring was fully ionized and heated by a flood of ultraviolet 
radiation.  Three and a half years later, the ring still glows at 
a temperature of more than 20,000 degrees Kelvin.
 
     The slowly expanding ring is destined to be a relatively 
short-lived structure.  It will be overtaken by the swiftly 
moving ejecta, travelling at 1/10th the speed of light, from the 
supernova in a few more years.  This collision will heat the ring 
such that it will brightly glow in X-ray and ultraviolet light.  
Within a few decades, the ring will be completely engulfed by 
supernova debris which will be visible for centuries as a bright 
supernova remnant.
 
     The Space Telescope Science Institute is operated by the
Association of Universities for Research in Astronomy, Inc., for
NASA, under contract with the Goddard Space Flight Center,
Greenbelt, Md.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                         Hubble Space Telescope Update
                                August 30, 1990

     The most interesting news of the past two weeks has been the results,
some of them quite spectacular, from the initial round of Science Assessment
Observations (SAO).  Regarding spacecraft events, the past 2 weeks have
produced one instrument safing in the High Speed Photometer (HSP), one Hubble
Space Telescope (HST) safing event (software sunpoint), some Fixed Head Star
Tracker (FHST) and Fine Guidance Sensor (FGS) failures and loss-of-lock.
Currently all is progressing smoothly with HST.  A 7 day Optical Telescope
Assembly (OTA) characterization Science Mission Specification (SMS) that is
designed to gather Faint Object Camera (FOC) and Wield Field/Planetary Camera
(WFPC) data at a variety of secondary mirror positions specifically for the
characterization of the OTA aberrations.  This SMS begins on August 30 and
will run through September 6.

     There has been a small amount of news on the Pointing Control Subsystem
(PCS) day/night terminator induced jitter (officially known as the SAGA
(Solar Array Gain Augmentation)) fix.  It appears that the current SAGA will
produce something on the order of a factor of 30 reduction in the jitter (this
achieves the pre-launch PCS spec) but it requires too much on board CPU time
to do this.  This SAGA model is under review to either reduce CPU usage for
the current scheme or come up with a different technique that is less CPU
intensive.  The immediate result of this is a delay in the delivery and
implementation of any jitter fix.  No new date for a SAGA delivery will be
set until after the software has been reviewed (~7-10 days).  With regards
to the FGS there is one item of interest.  New operational criteria have been
implemented to reduce the loss of lock (and data) produced by the SAA,
terminator crossing and the such: if the guide stars are fainter than 13
only coarse track with the clear filter will be requested, if the stars are
brighter than 13, fine lock with the 2/3 aperture will be requested.
Stability under coarse track has been qualitatively good (quantitative
results are in progress) and the new limits have improved FGS performance,
but FGS loss-of-lock is still occurring and some data has been lost.  Also,
this current OTA characterization SMS contains a lot of FGS transfer scans
at a number of focus positions that should establish a good estimate of FGS
performance.  The FHST's performance has not changed in the past two weeks,
most updates are working but failures are still occurring (spoiler stars
being the most frequent problem) with resulting loss of data.  A renewed
effort has begun to reduce the FHST failure rate.  The HST safing event, a
software sunpoint, occurred on August 19 (20:54 UT).  Briefly, the FGS's lost
lock and could not reacquire; gyro speeds quickly ramped up triggering a
software sunpoint.  The detailed cause of the safing event is under study.
Recovery from this safing event was quite rapid with resumption of the
SAO/ERO SMS by 01:00 UT on August 22.

     There has been little news regarding the HST focus and image quality.
The OTA characterization SMS that has just begun is scheduled to obtain FOC
and WFPC images and FGS transfer scans at positions close to the current focus
(-10 microns with respect to the "Goddard Zero" position of the secondary
mirror), specifically at -5, 0, and +5 microns.  This will be followed by a
series of FOC and WFPC images obtained at five focus position far from the
nominal focus (-265, -260, -90, +250, and +420 microns) to better
characterize the OTA aberrations.

     In general the Early Release Observations (ERO) and Science Assessment
Observations (SAO) continued to yield good results.  There were the expected
data losses due to PCS problems, exposure time problems, and pointing problems,
but all in all they went quite well -- and some of the results were quite
spectacular.  Below is a list of what was taken, FOC first then WFPC, giving
the object, whether it is an SAO or ERO target, and a brief comment.  Much of
this data is still being reduced, so the comments tell little about what is
seen in the image.

FOC images:

  o PKS0521-36, a radio galaxy with a jet (SAO):   successful exposure.
  o Arp 220, interacting galaxy (ERO):   failed -- coordinate error.
  o AP Lib, QSO with fuzz (SAO):   successful exposure.
  o R136, LMC cluster (SAO):   partial success -- underexposed.
  o R Aqr: symbiotic star with mass ejection (SAO):   successful exposure
  o Crab Nebula, SNR (ERO):   failed -- severely underexposed.
  o SN 1987A, "THE" supernova (SAO):  successful exposure: an emitting ring of
    gas was found surrounding the SN, one of the subjects of the NASA
    press conference held on August 29.
  o HH1, Herbig-Haro object (ERO):   failed -- severely underexposed.
  o Ton 256, QSO with fuzz (ERO):   successful exposure but no fuzz seen.
  o M 14, looking for a historical nova in the globular cluster (an FOS SAO
    proposal):   successful exposure.
  o NGC 1068, looking at the core of a seyfert galaxy (an FOS SAO proposal):
    successful exposure.
  o G2237+0305, gravitational lens (SAO):   successful exposure.


WFPC images:

  o NGC 1850, LMC cluster (SAO):   1 of 2 images a success, failure due PCS
    problem -- will probably be repeated.
  o NGC 7457, a normal S0 galaxy (SAO):   successful exposure: an unexpectedly
    bright core was found at the center of this galaxy, one of the
    subjects of the NASA press conference held on August 29.
  o NGC 925, an intermediate distance galaxy (SAO):   successful exposure.
  o IZw1, galaxy (ERO):  failed -- obtained with WF instead of PC.
  o R136, cluster in LMC (ERO):   partial success: UV exposure is fine but
    green exposure is overexposed.
  o eta Car, self explanatory (ERO):   failed -- PCS problem.
  o M 15, globular cluster (SAO):   effective failure -- 8 of 9 exposures lost
    due to PCS problems.
  o Saturn and Titan, self explanatory (ERO):   successful exposures.


     The Astrometry Team (AST) is beginning work on the mini-sweep data
currently being obtained with the FGS's.  FOC is taking a series exposures in
support of the OTA characterization effort.  The ERO and SAO observations
taken with the FOC are discussed above.  HSP went into safemode on August 24
due to too many counts being seen in the Photomultiplier Tube (PMT) as it
drifted across the bright limb of the earth.  Recovery was made and all is
well with HSP.  Next HSP activity is in on September 10.  WFPC is in the
process of supporting the OTA characterization.  WFPC SAO and ERO activities
are discussed above.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 12 Sep 90 20:00:46 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

NASA RELEASES THREE HUBBLE SPACE TELESCOPE SCIENCE PHOTOGRAPHS
 
     Photographs of the first science images taken by the 
European Space Agency's Faint Object Camera, onboard the Hubble 
Space Telescope, are available to media through NASA's audio 
visual branch.
 
     One photograph shows four images of a very distant quasar 
which have been "multiple-imaged" by a relatively nearby galaxy 
acting as a gravitational lens.  The quasar is approximately 8 
billion light years away, whereas the galaxy, 400 million light 
years away, is 20 times closer.  The light from the quasar is 
bent in its path by the gravitational field of the galaxy.  
 
     For the first time, the exploding outer envelope of SN 1987A 
has been photographed directly.  A close look at the Supernova 
shows a curious luminescent ring surrounding the exploded star.  
This ring should help astronomers determine the nature and 
history of the progenitor of the Supernova.
 
     The most detailed and highest resolution photograph ever 
taken of the young, compact star cluster R136 also is 
available.  This star cluster is located in the center of the 30
Doradus nebula in the Large Magellanic Cloud, a neighboring
galaxy at a distance of 170,000 light years.
 
     The Hubble Space Telescope is a project of international
cooperation between NASA and the European Space Agency.
 
     Media representatives only may obtain these photos, free of
charge, by writing to or phoning Broadcast & Audio Visual Branch,
PMD/NASA Headquarters, Washington, D.C. 20546   (Phone:  202/453-
8383).
 
     Photo Numbers:
     B & W:   90-H-616,   90-H-617,   90-H-618

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

>     Photo Numbers:
>     B & W:   90-H-616,   90-H-617,   90-H-618

From the looks of those numbers, I think it's pretty clear that the "90" means
1990 and "H" stands for "Hubble", but does the 616-618 imply that there are at
least that many photographs already?

Wook

    Probably that many exposures, but not that many photographs - at least
    not that many photographs worth looking at.
    
    - dave

    Re:.141 & .142
    	A lot of those exposures so far were probably test exposures to
    test the imager, focusing tests, and aberration characterization tests.
    
    				Drew
    

For those who really want these pictures...

Unless one of our readers is a member of the media, you can apparently get
the photos from (courtesy USENET):


>The name of the Contractor is "Bara King Pictures". Address is
>4805 Frolich Lane, Hyattsville, Maryland 20781. They have color,
>and black & white pictures in any size you might want. Slides are
>also available. The price of the Color prints are $9 each, $6 for
>the black & white. I didnt ask about the slides. Add 15% for postage.
>Not too bad IMHO. For all of those who responded to my initial posting
>thanks for all the help. 
>Gary Andreas
>DLA SYSTEMS AUTOMATION CENTER
>Columbus, Ohio 43216-5001
>(614)238-5830


They are authorized by the U.S. Gov. to resell the pics.   I believe you
can use the same photo numbers specified in the previous note.


FYI,

- dave

    This from the NEWS BRIEFS column in Aviation Week, Sept 17, 1990 pg 42
    
    Copied without permission.
    
    Hubble Space Telescope investigators have found that an error made in
    transposing the design of a measurement device from the drawing board to
    an assembly room at Perkin-Elmer is the reason the observatory's
    primary mirror was designed with a serious flaw.  The mathmatical error
    led to an error in assembling the null corrector device used to measure
    the mirror during its shaping.  Investigators are examining whether
    Perkin-Elmer discounted warnings that the corrector was flawed.
    
    
    Mike H.

From: [email protected] (Ron Baalke)
Date: 22 Sep 90 22:05:12 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

   The following is a Hubble Space Telescope status report from Ron Polidan,
   astronomer on the HST team.
----------------------------------------------------------------------------

                               HST Status Report
                               September 5, 1990


Current Status and Summary

Since my last report the Hubble Space Telescope (HST) has been engaged in a
general Optical Telescope Assembly (OTA) focus and characterization Science
Mission Specification (SMS).  This SMS was divided into two parts: a
"mini-sweep" focus run designed to explore focus space around the current
mirror position and a "big-sweep" portion that was designed to gather data at
secondary mirror positions that are far from focus in order to provide the data
necessary for full characterization the OTA aberrations.  For the most part the
mini-sweep run went well, some data was lost, but the necessary data was
obtained.  The big-sweep OTA characterization run is still in progress.  So far
it has not fared as well as the mini-sweep run; a lot of data has been lost due
to the problems of attempting to guide on very out of focus images.  Details of
these runs are given below.  Other than the OTA focus and characterization runs
things have been rather quiet.  There have been no new Early Release
Observations (ERO) or Science Assessment Observations (SAO),
the next one scheduled is a Faint Object Camera (FOC) observation of
Pluto/Charon on Friday (September 7).


Pointing Control Subsystem (PCS)

There has been no further news on the PCS day/night terminator induced jitter
(officially known as the SAGA = Solar Array Gain Augmentation) fix since my
last report.  An analysis of the problems encountered with the previous scheme
(excessive CPU time) is in progress with a report due out at the end of this
week or the beginning of next week.  In a few weeks time we should have a good
estimate of the Fine Guidance Sensor (FGS) performance.  During the mini-sweep
focus run a lot of FGS S-curve data was obtained.  These data are currently
under analysis by the Astrometry team (AST) .  The only news on the Fixed Head
Star Tracker's (FHST) performance is that there are meetings going on between
the builders of the FHST's and the PASS people to attempt to clarify the
mechanical operation of these instruments.


HST Focusing and Image Quality

For the past week we have been running a focus and OTA characterization SMS
and with HST.  This SMS has two parts.  The first part is a focus "mini-sweep"
that obtains FOC and Wield Field/Planetary Camera (WFPC) images and FGS
transfer scans at positions close to the current focus (-10 microns with
respect to the "Goddard Zero" position of the secondary mirror), specifically
at -5, 0, and +5 microns.  This portion of the SMS is complete and good data
was obtained at all positions.  Some data was lost due to a variety of PCS
problems, mostly FGS loss-of-lock, but enough data was obtained to
successfully complete the run.  The second part of the SMS is the "big-sweep"
OTA characterization effort.  This proposal was designed to obtain a series
of FOC and WFPC images at five focus position far from the nominal focus
(-265, -260, -90, +250, and +420 microns) to better characterize the OTA
aberrations.  As of this report we are a little over half way through this
proposal: the +420, and +250 micron positions are complete and we are
almost through with the -90 micron measurements.  Things have not gone
terribly well.  Some WFPC data has been lost and a large amount of FOC has
been lost due to guiding problems with the out of focus images -- at the very
out of focus positions the FGS's have difficulty in holding lock and have
imparted erroneous drifts on the spacecraft at the beginning of occultation
periods, producing failed reacquisitions at the next observing period.  The
biggest single loss was at the +250 micron position with all the FOC data at
this position lost. Needless to say a major effort was mounted to understand
the details of the problem, a possible solution was proposed and installed --
it will be tested later tonight (September 5) when the mirror is moved from
the -90 micron position (where the images are "good" as far a guiding
requirements) to -260 microns.


ERO and SAO Programs

There has been no news on the Early Release Observations (ERO) and Science
Assessment Observations (SAO) since my last report.  All the teams are working
on the analysis of the data.  There will be an ESA press conference in the near
future releasing some of the FOC images.   Preliminary results on some of the
images have been discussed at various meetings.  Below is a brief update of
what has been seen in the successfully exposures.  Remember these are
preliminary reports!

FOC images:

   o PKS0521-36, a radio galaxy with a jet (SAO):   the jet has been detected.
   o AP Lib, QSO with fuzz (SAO):   fuzz is detected.
   o R136, LMC cluster (SAO):   underexposed in both F/96 and F/288 but under
     study.
   o R Aqr: symbiotic star with mass ejection (SAO): very interesting exposure.
     The "tail" is seen in [O II] and [O III].
   o SN 1987A, "THE" supernova (SAO):  ring of gas seen in [O III] and not the
     continuum.
   o Ton 256, QSO with fuzz (ERO):   successful exposure but no fuzz seen.
   o M 14, looking for a historical nova in the globular cluster (an FOS SAO
     proposal):   good deep image.
   o NGC 1068, looking at the core of a seyfert galaxy (an FOS SAO proposal):
     structure seen in the nucleus.
   o G2237+0305, gravitational lens (SAO):   four distinct objects are seen
     along with something (fifth QSO image or galactic nucleus) at or near the
     center of the lensing galaxy.


WFPC images:

   o NGC 1850, LMC cluster (SAO):   in this crowded field, 15-20% photometry
     is the best they could do so far.
   o NGC 7457, a normal S0 galaxy (SAO):   analysis of the unexpectedly bright
     core was found at the center of this galaxy is in progress.
   o NGC 925, an intermediate distance galaxy (SAO):   underexposed -- did not
     get very deep.
   o R136, cluster in LMC (ERO):   analysis in progress.
   o Saturn and Titan, self explanatory (ERO):   analysis in progress.


SMS's

All is going smoothly.  The current OTA characterization SMS runs through
Thursday, September 6.  This will be followed by a 81 hour SMS containing a
Pluto/Charon SAO exposure and Scientific Instrument (SI) activation proposals.
This, in turn, will be followed by a 7 day SMS that will contain the first
new ground system software release (F0) since launch and the Faint Object
Spectrograph (FOS), Goddard High Resolution Spectrograph (GHRS), High Speed
Photometer (HSP), and OTA testing.  SAO/ERO observations will begin again
around September 17.


SI's

AST is working on the large amount of FGS transfer scan data that was obtained
over the past week.

FOC is taking a series exposures in support of the OTA characterization effort.

FOS has been in hold (18 consecutive days).  The next FOS activity is in the
253 (10 Sept) SMS.

GHRS is in hold and has no planned activities until the 10 Sept SMS.

HSP is in hold and has no planned activities until the 10 Sept SMS.

WFPC is in the process of supporting the OTA characterization.  WFPC SAO and
ERO activities are discussed above.

    Ron Polidan
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 23 Sep 90 16:07:42 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

The following is a HST status report from Ron Polidan, astronomer on the
HST team.
--------------------------------------------------------------------------
                               HST Status Report
                               September 10, 1990


Current Status and Summary

During the past five days of operations the Hubble Space Telescope (HST)
completed the Optical Telescope Assembly (OTA) focus and characterization
Science Mission Specifications (SMS), ran a short (81 hour) SMS that contained
a Faint Object Camera (FOC) observation of Pluto/Charon and Scientific
Instruments (SI) (FOC, Wide Field/Planetary Camera (WFPC), and High Speed
Photometer (HSP)) testing.  The Pluto/Charon observations were not fully
successful:  a failed guide star acquisition (a missing ~11.5 magnitude star
in Fine Guidance Sensor 1 (FGS1)) resulted in the loss of all the F/96 data.
A major effort by the operations personnel on Saturday (September 8) did
turn things around and 3 FOC F/288 images were obtained.  Yesterday, we began a
7 day SMS that contains installation of the new F0 release ground system and
FOS, Goddard High Resolution Spectrograph (GHRS), HSP, and OTA testing: all is
going very well so far.  This SMS will run through Sunday (September 16) and
will be followed by another 7 day SMS containing more SI testing and the next
round of Early Release Observations (ERO) and Science Assessment Observations
(SAO) proposals.


Point Control Subsystem (PCS)

There is an update on the PCS day/night terminator induced jitter (officially
known as the SAGA = Solar Array Gain Augmentation) fix.  A reworking of the
SAGA software is in progress with a new delivery date of mid-October.  Not a
lot new on the Fixed Head Star Tracker (FHST) and FGS's other than the analyses
are making good progress.  The FGS acquisition failure over the weekend was of
interest:  The primary guide star was an ~11.5 magnitude star.  All indications
were that the acquisition should have been trivial, FHST updates indicated a
good attitude and a 11.5 magnitude star is hard to miss.  FGS1 failed to find
the star however.  Subsequent FHST maps showed that indeed HST was at the
proper attitude to acquire the guide star -- it simply was not there.  Needless
to say, this FGS failure is under study, thoughts are that this "star" is
either an error in the guide star catalogue or a very large amplitude variable.


HST Focusing and Image Quality

In the past ten days we have obtained a substantial amount of focus and OTA
characterization data with HST.  As I stated in my last report the focus data
obtained appears adequate to answer the remaining questions regarding the HST
focus but the OTA characterization data is deficient.  Significant loss of data
occurred at the +420 and +250 micron position due to guiding problems, with all
FOC data at the +250 micron position being lost.  There was a greater success
at the negative secondary mirror positions with no significant data losses
occurring at the -90, -260, and -265 micron positions.  However, preliminary
analysis of the characterization data suggests that a number of them are
underexposed.  The problem is under study, so far it appears likely that the
cause of the underexposures was human error rather than hardware error.
Evaluation of the quality of the existing OTA characterization data is in
progress.  Preliminary indications are that the WFPC data at all five positions
and the FOC data at the -90 and -260 positions (no FOC data was scheduled at
the -265 position) are adequate for characterization.  The FOC +420 and +250
observations, however, will likely be repeated in the day 267 (September 24)
SMS.


ERO and SAO Programs

There has been only one new ERO/SAO since my last report:  Pluto and Charon
were observed with the FOC over the weekend.  As I stated above all did not go
well.  The initial guide star acquisition failed when an ~11.5 magnitude star
could not be found in the FGS pickle, all indications are that the spacecraft
attitude was correct -- the star was simply not there (see above for details of
the failure).  Herculean efforts by the operations staff at Goddard Space
Flight Center (GSFC) and ScI to recover from the guide star problems salvaged
3 of the 6 intended exposures, all with the F/288.  As for Pluto and Charon,
one clearly sees the two bodies (separation ~0.9 arcseconds) in the raw image.
Analysis of the data is in progress.  In my last report there was an error
in the table of ERO/SAO observations: I listed the NGC 1068 observation as an
FOC observation rather than a Planetary Camera (PC) observation -- it is a PC
observation.  Below is a corrected listing.

FOC images:

   o PKS0521-36, a radio galaxy with a jet (SAO):   the jet has been detected.
   o AP Lib, QSO with fuzz (SAO):   fuzz is detected.
   o R136, LMC cluster (SAO):   underexposed in both F/96 and F/288 but under
     study.
   o R Aqr: symbiotic star with mass ejection (SAO):   very interesting
     exposure. The "tail" is seen in [O II] and [O III].
   o SN 1987A, "THE" supernova (SAO):  ring of gas seen in [O III] and not the
     continuum.
   o Ton 256, QSO with fuzz (ERO):   successful exposure but no fuzz seen.
   o M 14, looking for a historical nova in the globular cluster (an FOS SAO
     proposal):   good deep image.
   o G2237+0305, gravitational lens (SAO):   four distinct objects are seen
     along with something (fifth QSO image or galactic nucleus) at or near the
     center of the lensing galaxy.


WFPC images:

   o NGC 1850, LMC cluster (SAO):   in this crowded field, 15-20% photometry
     is the best they could do so far.
   o NGC 7457, a normal S0 galaxy (SAO):   analysis of the unexpectedly bright
     core was found at the center of this galaxy is in progress.  See the
     discussion (below) of these observations by Tod Lauer.
   o NGC 925, an intermediate distance galaxy (SAO):   underexposed -- did not
     get very deep.
   o NGC 1068, looking at the core of a seyfert galaxy (an FOS SAO proposal):
     structure seen in the nucleus.
   o R136, cluster in LMC (ERO):   analysis in progress.
   o Saturn and Titan, self explanatory (ERO):   analysis in progress.

Finally, included in this Status Report is a more technical discussion of the
WFPC observations of NGC 7457 from Tod R. Lauer of the WFPC team.


*** Report on NGC 7457 from Tod R. Lauer of the WFPC Team ***

This is a brief discussion of the WFPC IDT SAO observations of NGC 7457.  This
object, a normal nearby S0 galaxy, was observed to evaluate the feasibility of
conducting investigations on galactic nuclear structure with HST in its present
condition.  The results presented here are preliminary and are not for
attribution.

NGC was observed with the PC in two filters, F555W and F785LP, which
approximate Johnson V and I.  Total exposure time in each filter was 800
seconds.  The distribution of light in NGC 7457 for R<10'' appears to be
consistent with a smooth, featureless power-law with slope of -0.9.  No
evidence of a smooth core is seen.  Any core present must have r_c<0.056'' or
3.4pc, assuming a distance of 12.5 Mpc (H_0=80).  A central luminosity density
in excess of 3X10^4 (solar units) is implied.  At this time, M32 is the only
object known to have a core more compact than these limits, and indeed the
light profile of NGC 7457 resembles that of M32 at the same physical scale.  At
this time, there is no dynamical evidence that there is a massive black hole in
the nucleus of NGC 7457, in contrast to M32, but the compact nature of the NGC
7457 nucleus suggests that this would be an excellent target for high spatial
resolution spectra to investigate this problem.  The light is concentrated
enough in the center of NGC 7457 so that these observations could be done with
the HST spectrographs at present.
                                             Tod R. Lauer


SMS's

All is still going smoothly, we are back to 7 day SMS, running from 0 hours UT
on Monday (September 10) through the following Sunday.  The current SMS just
started and runs through 16 September.  The content of this SMS is
installation for the F0 release of the ground system and SI (Faint Object
Spectrograph (FOS), OTA, GHRS, and HSP) testing.  The next SMS (day 260,
September 17 ) continues the SI testing but also contains more
SAO/ERO observations.  The installation of the F0 ground system is going
extremely well -- there have been no significant problems to date.  Completion
of the installation of this software will provide additional capabilities to
HST operations.


SI's

The Astrometry Team (AST) continues to process their S-curve data, looking
to remove spacecraft jitter from the S-curves.

FOC successfully ran their UV throughput proposal, the data is being analyzed.
As I stated above the Pluto/Charon data is under study.  A PSF proposal that
ran just before the Pluto/Charon exposures had significant underexposures, with
the last two images yielding no obvious star.

FOS is still in hold.  The next FOS activity is Thursday morning, September 13.

GHRS is out of hold.  The are Detector Stabilization proposals -- all is going
well so far.

HSP got out of hold this weekend running a Relative Aperture Location for
Detector 4.  Everything went well -- no anomalies.

WFPC is looking at their OTA characterization data.  Over the weekend they also
ran a series of flats and the last part of their Linearity proposal.  No
anomalies have been reported for any of these tests.

    Ron Polidan
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.

The following is a HST status report from Ron Polidan, astronomer on the
HST team.
--------------------------------------------------------------------------
                               HST Status Report
                               September 15, 1990


Current Status and Summary

Since my last report on we have been in an Science Mission Specification
(SMS) that is bringing a new operations ground system (version F0) on line,
running an Optical Telescope Assembly (OTA) mini-OFAD (Optical Field Angle
Distortion) test, Fine Guidance Sensor (FGS) to FGS alignment, and S-curve
calibration, and conducting Scientific Instruments (SI), specifically Faint
Object Spectrograph (FOS), Goddard High Resolution Spectrograph (GHRS), and
High Speed Photometer (HSP), testing. The F0 installation was an outstanding
success, virtually no problems were encountered in bringing this new software
into full operation.  The OTA testing was less successful with Pointing
Control Subsystem (PCS) problems conspiring to produce significant data
losses.  All SI testing went extremely well:  FOS successfully turned on after
about a month in hold, GHRS saw starlight (no spectrum) as did HSP in coarse
alignment testing.  The "big" news this week was a report from the Allen
committee that identifies the possible cause of the misfiguring of the HST
primary mirror: a ~1.3 mm error in the placement of the field lens in the
reflective null lens.  Late on Sunday (September 16, 8PM EDT) we begin a
new SMS; it will run for 7 days and contains more SI testing and the next
round of Early Release Observations (ERO) and Science Assessment Observations
(SAO) proposals.  Also included in today's report is a summary of the
M14 observations made with the Wide Field/Planetary Camera (WFPC) by Bruce
Margon of the FOS team.


Allen Committee Findings

This is a brief report on the recent findings of the of the Allen committee.
The information was derived from a single short presentation so it is by no
means a full and complete review.  Their findings are also difficult to explain
in detail without a few diagrams, so I will attempt to give only a top level
overview in this report.  This is my view of what I was told.  The problem
ultimately derived from the use a small pinhole aperture plate that was placed
on one end of an INVAR rod that was used to set the focal distance of a field
lens in the reflective null lens.  An INVAR rod was manufactured to set the
distance between the field lens and the focal point of the incoming beam.  The
rod has spherical ends and there was concern that the incoming beam could not
be accurately focused on the exact center of the rod so an aperture plate, a
very thin piece of metal with a pinhole was manufactured an placed on a mount
to slide on the end of the INVAR rod.  Testing of the aperture plate/INVAR rod
combination gave the desired results: a reflection was seen off (apparently)
the INVAR rod only at one position with no reflection at any other position.
Unfortunately, the mount was not as good a fit on the rod as it should have
been and the aperture plate had a small "problem:"  in making the pinhole a
small polished ring around the opening was produced.  The mount held the
aperture plate above the the INVAR rod, too far above the rod to allow the
incoming beam (an F/1 beam, I think) to pass through the hole an reflect off
the end of the rod.  The polished ring around the pinhole did, however, produce
a clean reflection.  So while all looked normal the reflection was actually
coming from a surface ~1.3 mm above the end of the INVAR rod.  The net result:
a 1.3 mm error in focal length in the reflective null lens and spherical
aberration in HST.  The current measurement of the focal length error is 1.33
plus/minus 0.05 mm.  The expectation is that the focal length error should be
measurable to ~5 microns uncertainty.


PCS

There has been no further news on the SAGA (Solar Array Gain Augmentation) fix:
the new delivery date is still mid-October.  Steady progress is being made on
the variety of Fixed Head Star Tracker (FHST) and FGS problems that have been
plaguing HST.  Operations are still being effected by PSC failures.  This past
week the mini-OFAD, FGS to FGS alignment, and FGS S-curve calibration were all
heavily impacted by PCS failures.  Big impulses at the terminator crossings
produced many FGS loss-of-locks, FHST problems, one an onboard computer (DF224)
bug, added a few more problems.  The net result being that all three tests were
compromised.  Good data was obtained for all three tests but not a complete
data set.  Analysis of the data is in progress to see if enough good data was
obtained.  It is very likely that repeats will be required.  The recent FHST
and FGS failures have greatly increased the effort to solve the problems.  The
Astrometry team (AST) appears to be making significant progress in
understanding the oddities that show up in the FGS S-curves.  The builders of
the FHST's have been called in to answer questions on the details of how the
FHST work and the Astrometry Team is producing an FHST tool based on the FGS
Pickles program to assist in identification of good FHST fields.  On another
issue, the missing ~11.5 magnitude guide star from the Pluto/Charon
observations is still under study.  A faint star was reported at that position
in plates taken at the U. of Virginia and there is a suggestion that the object
may be extended on the GSS plates.  Obviously, more on this a future report.


HST Focusing and Image Quality

Nothing new here other than the report from the Allen committee discussed
above.  The Faint Object Camera (FOC) portion of the "Big Sweep" OTA
characterization run that was lost a couple of weeks ago has been rescheduled
for the day 267 (September 24) SMS.

ERO and SAO Programs

No new ERO or SAO observations have been made since my last report.  Starting
Monday (September 17) we will been a new SMS that contains a number of SAO
observations.  I will have a full report on these observations in my next
report.  In my previous report I stated that there was three successful FOC
Pluto/Charon exposures out of 6 attempts, actually it was 4 out 14 attempts:
0 out of 8 for F/96 and 4 out of 6 for F/288 (F342W and F430W images).
Another attempt at Pluto/Charon is scheduled in the day 260 (September 17)
SMS.  Again below is a listing of the current SAO and ERO observations.

FOC images:

   o PKS0521-36, a radio galaxy with a jet (SAO):   the jet has been detected.
   o AP Lib, QSO with fuzz (SAO):   fuzz is detected.
   o R136, LMC cluster (SAO):   underexposed in both F/96 and F/288 but under
     study.
   o R Aqr: symbiotic star with mass ejection (SAO):   very interesting
     exposure.  The "tail" is seen in [O II] and [O III].
   o SN 1987A, "THE" supernova (SAO):  ring of gas seen in [O III] and not the
     continuum.
   o Ton 256, QSO with fuzz (ERO):   successful exposure but no fuzz seen.
   o M 14, looking for a historical nova in the globular cluster (an FOS SAO
     proposal):   good deep image.  See the report from Bruce Margon below.
   o G2237+0305, gravitational lens (SAO):   four distinct objects are seen
     along with something (fifth QSO image or galactic nucleus) at or near the
     center of the lensing galaxy.
   o Pluto/Charon: partial success 4 F/288 images (F342W and F430W).  No F/96
     images.


WFPC images:

   o NGC 1850, LMC cluster (SAO):   in this crowded field, 15-20% photometry
     is the best they could do so far.
   o NGC 7457, a normal S0 galaxy (SAO):   analysis of the unexpectedly bright
     core was found at the center of this galaxy is in progress.
   o NGC 925, an intermediate distance galaxy (SAO):   underexposed -- did not
     get very deep.
   o NGC 1068, looking at the core of a seyfert galaxy (an FOS SAO proposal):
     structure seen in the nucleus.
   o R136, cluster in LMC (ERO):   analysis in progress.
   o Saturn and Titan, self explanatory (ERO):   analysis in progress.

Finally, included in this Status Report is a more technical discussion of the
FOC observations done by the FOS team of M14 from Bruce Margon of the FOS
team.


******* Report on M14 by Bruce Margon of the FOS IDT (Instrument Development
        Team)

This is a brief, preliminary report of the FOS IDT SAO observations of M14.
These observations were derived from part of the FOS GTO program, consisting
of imagery of the region of the globular cluster M14 containing the nova of
1938, followed by FOS spectra of the quiescent counterpart. The results
mentioned here are not for attribution.

M14 was observed in U and B filters in the FOC f/96 mode, with two exposures
totalling 2500 s in each filter. Because current acquisition errors are not
small compared with the f/96 field (11 x 11"), a realtime acquisition was
performed. Normal finding charts from ground-based data prove to be barely
sufficient for HST imagery in globular clusters! The field was identified by
R. Downes and S. Anderson of the FOS team only with great difficulty: hundreds
of stars were detected even in the brief (600 s) 22 x 22" acquisition image.
The pointing proved to be excellent (within 2" of desired).

The observations were conducted in coarse rather than fine lock as would
ordinarily be desired at this scale; as a result the images are not of optimum
shape, and differ slightly on each of the four exposures. None the less the
results are impressive indeed. Several hundred stars are easily resolved in
the 11" field. The fields are uncalibrated but certainly reach fainter than
U=B=21, possibly much fainter. Numerous faint stars apparently single in
ground-based Charge Coupled Device (CCD) imagery are clearly resolved into
multiple objects. The quiescent nova candidate previously suggested from
ground-based imagery by Shara et al. (1986) is well-detected, and also multiply
resolved (as was speculated would be the case by those authors). Analysis is
currently underway to identify the strongest candidate for the nova.

Two Planetary Camera (PC) exposures at H-alpha totalling 2500 s were also
obtained, but are badly underexposed and not useful.

                             Bruce Margon

**************


SMS's

SMS's continue to run to 7 days, from 0 hours UT on Monday through the
following Sunday.  The next SMS (day 260 SMS) starts at 0 hr UT on September
17.  It contains any SAO observations and numerous SI check-out tests.  The
following SMS (day 267, September 24 ) is similar in structure but with more
SI testing and less science observations.  The next SMS (day 274, October 1),
as currently planned, has the first GHRS SAO observation: an observation of
the Hg star chi Lupi.


SI's

AST continues to process their S-curve data, removing spacecraft jitter from
the S-curves.  As discussed above they have also begun development of an FHST
tool based on the Pickles FGS code to assist in identifying usable FHST fields.

FOC has had a relatively quiet week, having been in hold since my last report.
Evaluation of their UV images of BPM 16247 show that the UV throughput is about
as expected with no change seen over ~45 days.

FOS successfully turned on their High Voltage (HV) on Thursday morning,
September 13, after ~1 month in hold.  All went very well -- no problems or
anomalies.

GHRS ran a number of instrument tests this past week.  Detector Stability and
Pulse Height Analysis testing all went extremely well.  GHRS Coarse Alignment
runs also did well:  the expected star was clearly seen in the aperture ~1.8
arcseconds off from the Large Science Aperture -- a much better performance
then expected for the first attempt.  In general all went very well for the
GHRS.

HSP ran their Coarse Alignment test also.  The star was detected with a ~6
arcsecond offset.  The data is still under study..

WFPC, like FOC, has been essentially inactive this week with the support of the
GHRS Coarse Alignment test being the only operational activity.  Analysis of
their UV throughput data may show a lower UV (2300 A) throughput, by a factor
of ~4, then expected.  The data is being examined further.

    Ron Polidan
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    
    
    	hello,
    
    		Any pictures on the net from the HST since the last
    	lot ?
    
    	Chris

From: [email protected] (Ron Baalke)
Date: 26 Sep 90 03:46:12 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

The following is a HST status report from Ron Polidan, astronomer on the
HST team.
--------------------------------------------------------------------------
                               HST Status Report
                               September 18, 1990


Current Status and Summary

Not a tremendous amount has happened since I issued my last report.  The "F0"
Science Mission Specification (SMS) finished without any additional problems
and we successfully began a 7-day SMS that contains numerous Science
Assessment Observations (SAO) and Early Release Observations (ERO).
This SMS got off to an excellent start with successful Wide Field/Planetary
Camera (WFPC) "Sky Survey" images, Planetary Camera (PC) observations of
NGC 1850, Faint Object Camera (FOC) images of Pluto and Charon, in addition
to successful Scientific Instrument (SI) testing.  Included in todays report
is a summary of the NGC 1068 observations made with the WFPC from Ian Evans,
Lee Armus, Saul Caganoff, Holland Ford, and Anne Kinney for the Faint Object
Spectrograph (FOS) team. (In my previous report I stated in this section that
the M14 observations were made with the WFPC, they were really made with the
FOC.  The rest of my report gave the correct instrument.)


Allen Committee Findings

No changes and only a few additions from my last report.  The diameter of the
aperture is ~0.13 cm and the polished region that gave the reflection extended
~1.5 mm from the opening.  Preliminary measurement of the secondary mirror
"clone" seems to show that it is within specifications, there are more detailed
measurements upcoming.


Pointing Control Subsystem (PCS)

No new developments since my last report.


HST Focusing and Image Quality

Nothing new here since Saturday (September 15).


ERO and SAO Programs

With the beginning of the current SMS at 00:00 UT on Monday (September 17)
there has been a burst of SAO/ERO observations.  Part of these observations
are a group called the "Sky Survey" program.  This program consists of a
large list of selected galaxies for which short (~minutes) WFPC exposures
will be obtained.  The actual targeted galaxies are chosen because of their
nearness to a HST "primary" target, one in an approved OV or SV proposal,
and the availability of otherwise unusable time in the SMS.  Ten (10) such
observations appear in the current SMS.  I will get more information on this
program and present it in a future report.  SAO/ERO observations that have
been made since my last report are: 5 Sky Survey targets (WFPC), PC
observations of the LMC cluster NGC 1850, and a set of Pluto/Charon
observations by the FOC.  All these observations were obtained within the
past 2 days so there is not a lot of detailed information available.  All
indications are that all have gone very well.  The remainder of this SMS has
5 more Sky Survey observations, WFPC observations of M15, two NGC 188 (PSF
measurement), another NGC 1850, and FOC observations of Pluto/Charon
and the radio galaxy 3C66B.  Again below is a listing of the current SAO and
ERO observations, excluding those taken in the current SMS and mentioned above.

FOC images:

   o PKS0521-36, a radio galaxy with a jet (SAO):   the jet has been detected.
   o AP Lib, QSO with fuzz (SAO):   fuzz is detected.
   o R136, LMC cluster (SAO):   underexposed in both F/96 and F/288 but under
     study.
   o R Aqr: symbiotic star with mass ejection (SAO):   very interesting
     exposure. The "tail" is seen in [O II] and [O III].
   o SN 1987A, "THE" supernova (SAO):  ring of gas seen in [O III] and not the
     continuum.
   o Ton 256, QSO with fuzz (ERO):   successful exposure but no fuzz seen.
   o M 14, looking for a historical nova in the globular cluster (an FOS SAO
     proposal):   good deep image.
   o G2237+0305, gravitational lens (SAO):   four distinct objects are seen
     along with something (fifth QSO image or galactic nucleus) at or near the
     center of the lensing galaxy.
   o Pluto/Charon: partial success 4 F/288 images (F342W and F430W).  No F/96
     images.


WFPC images:

   o NGC 1850, LMC cluster (SAO):   in this crowded field, 15-20% photometry is
     the best they could do so far.
   o NGC 7457, a normal S0 galaxy (SAO):   analysis of the unexpectedly bright
     core was found at the center of this galaxy is in progress.
   o NGC 925, an intermediate distance galaxy (SAO):   underexposed -- did not
     get very deep.
   o NGC 1068, looking at the core of a seyfert galaxy (an FOS SAO proposal):
     structure seen in the nucleus.  See the report below from members
     of the FOS team.
   o R136, cluster in LMC (ERO):   analysis in progress.
   o Saturn and Titan, self explanatory (ERO):   analysis in progress.

Finally, included in this Status Report is a more technical discussion of the
WFPC (PC) observations done by the FOS team of NGC 1068 from Ian Evans, Lee
Armus, Saul Caganoff, Holland Ford, and Anne Kinney for the FOS Team.


******* Report on NGC 1068 from Ian Evans, Lee Armus, Saul Caganoff,
        Holland Ford, and Anne Kinney for the FOS Team

This is brief description of the FOS Instrument Development Team (IDT) SAO
imaging of NGC 1068; the exposures were taken directly from FOS GTO program
1036.  NGC 1068 is a nearby Seyfert 2 galaxy, and was observed to evaluate
the feasibility of conducting investigations into the structure of the
narrow line regions of nearby active galaxies with HST in its present
condition. The results presented here are preliminary and are not for
attribution.

NGC 1068 was observed with the PC in the filter F502N to study the
structure of the [O III] 5007 emitting gas, and in the filter F547M which
was used to provide a continuum image for subtraction.  Total exposure time
in the filters was 900 seconds for the narrow band filter, and 180 seconds
for the continuum filter.  The distribution of [O III] 5007 emission near
the nucleus of NGC 1068 clearly resolves the narrow line region into a
number of distinct narrow line clouds.  Maximum entropy image deconvolution
demonstrates that some of the clouds show evidence of being spatially
resolved, which implies cloud sizes of order of 3-6 pc, assuming a distance
of 10 Mpc. Three of the bright [O III] clouds appear to correspond closely
to the observed 1.3 cm triple radio structure in the nucleus.  However,
there also are visible narrow line clouds which do not correspond to the
observed radio structure. The narrow line clouds appear to be sufficiently
condensed to allow FOS spectrophotometry to disentangle much of spatial
structure.

      Ian Evans, Lee Armus, Saul Caganoff, Holland Ford, and Anne Kinney
         for the FOS Team

**************


SMS's

All is smooth.  In addition to the SAO/ERO observations discussed above the
current SMS contains FOC F/48 aperture location and linearity proposals, FOS
Red side coarse alignment, HV stability, and Blue side X-Pitch, Y-Pitch, and
Focus proposals, Goddard High Resolution Spectrograph (GHRS) Mode I target
acquisition and dark noise proposals, and High Speed Photometer (HSP) coarse
alignment proposal, plus a few other things.


SI's

The Astrometry Team (AST) continues to process their S-curve data, removing
spacecraft jitter from the S-curves.

FOC got off to a quick start this week with (apparently) successful
observations of Pluto and Charon.

FOS had a generally good weekend.  The finished their last instrument OV1 test
(Blue side Y-base), finding that the spectrum lower than expected, the impact
of this is being studied.  They also successfully ran Red side aperture
location -- finding a star ~3.5 arcsec from their aperture.

GHRS ran more tests over the weekend.  The only anomaly was a lower then
expected sensitivity in the N1 mirror.

HSP ran their Coarse Alignment test also.  The star was detected with a ~6
arcsecond offset.  The data is still under study..

WFPC has been active this week with the SAO/ERO observations discussed above.

That is all for today.  My next report will be issued sometime the week of 1
October.  Shortly I leave for Italy for 10 days (work not vacation).  I will
keep in touch electronically with HST events and if anything significant
happens I will issue a special report.  Otherwise, look for my next report to
come out late in the first week of October.

     Ron Polidan
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Saturn's Great White Spot article
Date: 17 Oct 90 18:07:15 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    Washington Times -- 10/17/90 - "Saturn Storm a Spectacle"
 
    "A gargantuan storm 1 1/2 times as wide as Earth has developed
suddenly in Saturn's atmosphere, and the Hubble Space Telescope will
be used to watch it, astronomers said today." 
 
    The Washington Times reports that an oval-shaped white spot some
12,500 by 3,100 miles in size has formed in the atmosphere of the
solar system's second largest planet. 
 
    The story cites information from astronomer Reta Beebe at the New
Mexico State University, who says that two smaller white spots have
developed along with the huge oval spot and that the three spots
together cover about 50,000 miles, nearly one third of Saturn's
circumference. 
 
    The report says that astronomers are so excited about this planetary 
storm that the Hubble Space Telescope (HST) will be used to study it. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 23 Oct 90 23:02:38 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

The following is forwared from Ron Polidan, astronomer on the HST team
------------------------------------------------------------------------

                               HST Status Report
                               October 12, 1990

Back Again

I suspect many were wondering if my HST status reports had stopped.  After two
weeks in Italy it took me a lot longer to "come up to speed" on the status of
HST then I was expecting.  This combined with a much higher density of meetings
since my return delayed the issuing of this report by about a week.  Beginning
with this report I will be back to the twice a week schedule that I had
maintained since July.  Since a lot has happened since my last report (18
September) I will not attempt to give a summary of everything that has happened
since 18 September in todays report.  Rather, in this report I will give
highlights (with some discussion) of events of the past 3 weeks with details
appearing in the next 3 or 4 reports.

Current Status and Summary

All is going reasonably well with HST.  In general the past three weeks have
passed without major observatory problems.  This is not to say all went
perfectly, there were the "usual" HST problems and the associated loss of data
these past weeks.  The SAGA (Solar Array Gain Augmentation, the day/night
terminator disturbance) fix has arrived at GSFC (Goddard Space Flight Center)
and is under review.  A lot of work has been done on the FHST (Fixed Head Star
Tracker) and FGS (Fine Guidance Sensors) problems that have plagued HST since
launch.  There have been no fundamental breakthroughs on either of these two
problems but steady progress is being made.  The SI's (Scientific Instruments)
were rather active these past weeks.  Significant advancement of the GHRS
(Goddard High Resolution Spectrograph) and the FOS (Faint Object Spectrograph)
toward science operation occurred during the past three weeks with GHRS
getting their first spectrum.  The only SI problem uncovered is that the FOS
Blue side has a magnetic shielding problem similar to but significantly smaller
than that seen on the Red side.  A UV flood guiding test for the WFPC (Wide
Field/Planetary Camera) was partially successful: the sun was clearly detected
but the pointing was a little farther off than desired. Numerous SAO/ERO
(Science Assessment Observations/Early Release Observations) were obtained,
most were quite successful.


Allen Committee Findings

Nothing significantly new here since my mid-September reports.


PCS (Pointing Control Subsystem)

There was lots of news on the PCS front in the past 3 weeks.  The long awaited
PCS fix has been delivered to GSFC and is undergoing final review.
Expectations are high that it will solve most (but not all) of the jitter
problems.  There is a meeting late yesterday (Thursday) to review arguments
with regards to the installation of the delivered software.  Since this is
flight software the primary concern is safety, although performance is
certainly being discussed.  As of the moment, no problems were found and,
pending one final high level review, all is set for installation.  Nothing
really new has happened with the FHST's.  A lot more data has been gathered, a
special tiger team has been formed, and some real progress is being made but
there has not been a significant change in the failure rate over the past 3
weeks.  The optimism that the problems with the FGS's will be removed with
"fine tuning" has virtually vanished.  Test and analyses done over the past
weeks now seem to suggest that fine tuning will do little to affect the quality
of the S-curves.  What is specifically causing the problem has not yet been
identified.  Needless to say this problem is getting high visibility.


HST Focusing and Image Quality

Nothing new here since mid-September.


ERO and SAO Programs

A number of new SAO/ERO observations were obtained over the past three weeks.
Two "new" aspects of the SAO/ERO program have occurred:  the first "Sky Survey
Snapshots" were obtained with the WFPC and the first spectrographic
observations by HST (GHRS) were completed.  The function and use of the Sky
Survey Snapshots were discussed in my previous report and are briefly discussed
below.  Below is an updated listing of the completed (and in progress) SAO and
ERO observations (both successful and failed observations) with a brief
description of the results.  Since this SAO/ERO list is getting rather long,
beginning with my next report I will include only new SAO/ERO observations or
updates on old observations reported in earlier Status Reports.

FOC (Faint Object Camera) observations:

   o PKS0521-36, a radio galaxy with a jet (SAO):   the jet has been detected.

   o AP Lib, QSO with fuzz (SAO):   fuzz is detected.

   o Arp 220, colliding galaxy (ERO), failed.

   o Crab Nebula, SN remnant (ERO), failed.

   o HH1, Herbig-Haro object (ERO), failed.

   o R136, LMC cluster (SAO):   underexposed in both F/96 and F/288 but good
     data.

   o R Aqr: symbiotic star with mass ejection (SAO): very interesting exposure.
     The "tail" is seen in [O II] and [O III].

   o SN 1987A, "THE" supernova (SAO):  ring of gas seen in [O III] and not the
     continuum.

   o Ton 256, QSO with fuzz (ERO):   successful exposure but no fuzz seen.

   o M 14, looking for a historical nova in the globular cluster (an FOS SAO
     proposal):   good deep image.

   o G2237+0305, gravitational lens (SAO):   four distinct objects are seen
     along with something (fifth QSO image or galactic nucleus) at or near the
     center of the lensing galaxy.

   o Pluto/Charon: (SAO) First observation: partial success 4 F/288 images
     (F342W and F430W).  No F/96 images.  Second observation: a partial
     success, this time with good F/96 images but most of the F/288 data lost.

   o 3C66-B, radio galaxy (SAO), successful.


GHRS observations:

   o chi Lup, Hg rich CP star (SAO), partial success.  A good Large Science
     Aperture spectrum but no Small Science Aperture data.

   o xi Per, interstellar line star (SAO), successful.  Data in both apertures
     was obtained, but the star was not centered in either aperture.

WFPC images:

   o NGC 1850, LMC cluster (SAO):  partial success only in 2 attempts.

   o NGC 7457, a normal S0 galaxy (SAO):   analysis of the unexpectedly bright
     core was found at the center of this galaxy is in progress.

   o NGC 925, an intermediate distance galaxy (SAO):   underexposed -- did not
     get very deep.

   o 1Zw1, active galaxy (ERO), failed.

   o NGC 1068, looking at the core of a seyfert galaxy (an FOS SAO proposal):
     structure seen in the nucleus.

   o R136, cluster in LMC (ERO):   analysis in progress.

   o Saturn and Titan, self explanatory (ERO):   analysis in progress.

   o M 15, globular cluster, first observation failed, a repeat was successful.
     Data is under study.

   o eta Car, young cluster (ERO),  first attempt failed, second attempt
     successful.

   o Comet Levy, comet, successful.

The "Sky Survey Snapshot" observations with the WFPC are very short
observations of galaxies, performed under gyro control only, that are used as
fillers in orbits were the planned observation finishes with usable observing
time remaining.  The galaxies are selected on the basis of their proximity to
the planned OV or SV observation target from a master list generated by
J. Bahcall, R. Doxsey, J. Gunn, O. Lahav, and D. Schneider.  Below is a list of
those that have observed over the past weeks, at the moment I do not have any
quality assessment of these observations, this will appear in a future report.

Sky Survey Snapshot Targets:

    S50014+48           Q0451-418           IE1711+712
    PKS0355-48          PKS0506-61          IE1704+710
    B20149+33           Q0551-366           4C58.27
    B20201+36B          PKS0743-67          1613.7+171
    PKS0225-01          S51039+81           PKS2150+05


SMS's (Science Mission Specifications)

All is going smoothly.  SMS's are being maintained at 7 day durations, running
from Monday through Sunday.  Most activity in the recent SMS's have been
SAO/ERO observations or SI OV/SV proposals.  The first round of OTA (Optical
Telescope Assembly) image characterization is and the next image
characterization effort, the HARP (Hubble Aberration Recovery Program) proposal
for the WFPC is scheduled to begin in the SMS that stars on 22 October.  The
SAGA installation is scheduled to begin on Monday (15 October) and will take 5
days to check out.  During this time SI activities will continue.  The first
attempt at fine lock with the SAGA in place is scheduled for Thursday, 18
October.


SI's


Below are brief summaries of what has happened to the SI over the past weeks.
In future reports I plan to add details.

AST (Astrometry Team) continues to work on understanding the FGS performance
and problems.  As stated above there is a general perception now that the FGS
problems are not just a matter of fine tuning.  Recent analyses have also
suggested that spacecraft jitter is not the fundamental FGS problem.  The
Astrometry team is also looking into the impact of these problems on their
science program.  A new proposal is being developed specifically to assess
this issue.

FOC got off to a quick start after my last report with a number of SAO/ERO
observations (see above).  This was followed by a number of instrument tests.
In general all is going well for the FOC.

FOS has had a busy three weeks, significantly advanced instrument readiness.
The current schedule has the first FOS SAO observation scheduled for the week
of 22 October.  One significant problem was discovered in FOS:  the Blue side
has a magnetic shielding problem similar to what was found for the Red side
but significantly smaller, ~25% of what was
found on the Red side.  FOS is currently spending a lot of time doing aperture
alignments without a lot of success at the moment but all the problems
encountered appear to be well understood and should not significantly impact
the first SAO observation.

GHRS has also had a busy three weeks.  The most significant event was their
first spectrum: the Hg-rich chemically peculiar star chi Lup.  The proposal was
designed to test how the aberrated image impacts spectral resolution.  The LSA
(Large Science Aperture) data was excellent but, unfortunately, the SSA (Small
Science Aperture) data (this aperture images directly onto one diode so
resolution is uneffected by image size) was lost because of a software problem.
Recently (yesterday) the GHRS looked at xi Per, specifically looking at
interstellar lines.  In this case data was obtained in both the LSA and SSA but
the star was not centered in either aperture.  Adequate data was obtained to
suggest (preliminarily) that deconvolution of LSA data gives a good match to
the SSA data.

HSP (High Speed Photometer) ran a number of instrument test these past weeks.
The only significant event was a decision to defer testing of the PMT
(Photomultiplier Tube), VIS, and POL detectors until
modifications to the bright earth avoidance angles are resolved.

WFPC has been active with the SAO/ERO observations discussed above and with
observing (or attempting to observe) the sun through the UV Flood light path.
The SAO/ERO observations were generally successful and the solar guiding
attempt went well: the sun was detected but at the edge of the scan pattern,
an error of ~0.5 degree.  This error was larger than desired but not a
surprise.

               Ron Polidan
      
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 24 Oct 90 01:11:50 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

The following is forwared from Ron Polidan, astronomer on the HST team
------------------------------------------------------------------------
                               HST Status Report
                               October 19, 1990

Current Status and Summary

All has not gone well with the SAGA (Solar Array Gain Augmentation) software on
HST.  It does appear that the software has greatly reduced the 0.1 Hz
oscillation produced by the solar arrays but it apparently was forcing the
gyros into "high mode" much more frequently than desired.  The SAGA is
currently disabled.  Testing of the SAGA software will continue to gather
additional data but it seems unlikely that this software will be kept on the
spacecraft in its present form.  Since my last report a week ago the Astrometry
team has been using the FGS's (Fine Guidance Sensors) to their first SAO
(Science Assessment Observation) -- Duplicity Among Hyades Stars, with mixed
results, GHRS (Goddard High Resolution Spectrograph) attempted to get an SAO
observation of alpha Tau, but observation was unsuccessful due to a failure of
the FGS's to acquire guide stars (incorrect guide star thresholds).  The rest
of the time HST was performing various SI (Scientific Instrument) tests,
these, in general, went well.


PCS (Pointing Control Subsystem)

The goal of the SAGA software was to remove the oscillations seen in the HST
pointing that are produced by thermal gradients warping the SPA's (Solar Power
Arrays).  Testing of the SAGA involved enabling and disabling it for periods of
time and followed by comparative analyses of performance.  The installation
went rather smoothly.  After a few days of testing a number of things became
clear.  First, the SAGA was very successful in removing the 0.1 Hz disturbance;
the estimate was a factor of 30 reduction in amplitude.  With this disturbance
gone the other oscillation frequencies known to exist in the data (ranging from
~0.3 to 0.6 Hz) were more visible but not amplified.  Unfortunately, the SAGA
was frequently forcing the gyros out of the "low mode" state necessary for
science operation and into a "high mode" state.  With the gyros in the high
mode state there there is also a probability of a safing event.  The frequency
of gyro high mode transitions was high enough to make it clear that the SAGA
fix will have to be reexamined.  In the course of the SAGA testing it was
discovered that  one part of the SAGA software, a torque limiting package, was
not disabled when the rest of the SAGA was turned off.  It was also noted that
with the SAGA off some gyro problems were still occurring, suggesting that the
torque limiter was part of the problem.  It was then discovered that the while
the torque limiting software could not be fully disabled it could be "patched"
to effectively remove it form the system.  This was quickly done and the gyro
problems disappeared.  At the moment plans are to continue testing of the SAGA
but in a manner that will have minimum impact of other HST operations.
Discussions and analyses are continuing but it appears unlikely that the
current SAGA software will be kept on the spacecraft.  It will probably be at
least next week (pending the test schedule) before we have some
definitive statements on the SAGA and its problems.  Nothing new with regards
to the FHST's (Fixed Head Star Trackers) or the FGS's since my last report.


HST Focusing and Image Quality

Nothing fundamentally new here since mid-September.  A few revised numbers:
the primary mirror conic constant: values range from -1.0145 to -1.0125 and
appear to be converging.  Error in the field lens: 1.33 +/- 0.05.


ERO (Early Release Observations) and SAO Programs

Two new SAO/ERO observations were attempted over the past week: the Astrometry
team proposal looking at "Duplicity Among Hyades Stars" and a GHRS team
proposal studying the "Chromosphere of Alpha Tauri."   The Astrometry proposal
is the second of three runs, the final run is scheduled for the SMS (Science
Mission Specification) beginning on 29 October.  At this early stage in the
proposal the only comment that has been made is that "results are mixed."  The
results of the GHRS alpha Tau proposal were much less than "mixed" -- no data
on alpha Tau was obtained.  No guide stars were acquired and the star was never
placed in the instrument aperture.  It appears that incorrect FGS thresholds
for the acquisition were in the SMS.  This proposal will be rescheduled.
Nothing additional on any of the earlier SAO/ERO observations.  (Remember
beginning with this next report I will list only new SAO/ERO observations or
updates on old observations reported in earlier Status Reports.)  Below is a
list of the recent SAO/ERO observations and those planned in the next two
weeks.


AST (Astrometry Team):

   o Duplicity Among the Hyades (SAO) -- first two parts completed (no
     assessment), final run scheduled for the week of 29 October.

   o Orbital Parameters of Known Binaries -- scheduled for the week of 29
     October.


FOC (Faint Object Camera):

   o No new observations or results.


FOS (Faint Object Spectrograph):

   o Imaging of NGC 1566 with the PC (SAO) -- scheduled for 27 October.

   o Helium in the Early Universe (target UM 675) (SAO) -- scheduled for 28
     October (this is the first FOS instrument SAO/ERO observation).

   o Red Side Spectrophotometry of NGC 1068 -- scheduled for the week of 29
     October.


GHRS:

   o Chromosphere of Alpha Tau -- Failed, no guide stars (will be rescheduled)

   o Circumstellar Matter Around Beta Pictoris -- scheduled for 23 October


HSP (High Speed Photometer):

   o No new observations.


WFPC (Wide Field/Planetary Camera):

   o No new observations or results.


SMS's

All is going reasonably well.  Most activity in the current SMS's was directed
toward the SAGA installation and testing.  Beginning Monday (22 October) we
begin an SMS that contains OTA (Optical Telescope Assembly) image
characterization, an FOC mini-sweep image characterization and the HARP
(Hubble Aberration Recovery Program) proposal for further characterization of
the WFPC.  Also included in this SMS are FOC, FOS, and HSP instrument testing,
the GHRS SAO observation of Beta Pic, and an OTA mini-OFAD (Optical Field
Angle Distortion) proposal.  The following SMS (29 October) has more SI
testing, AST and FOS SAO/ERO observations, more FOC mini-sweep image
characterization, a desorption monitoring proposal, and a WFPC UV
Flood guiding test.


SI's

There is a pointing problem that is affecting all SI's to some degree.  It
appears that there is an uncertainty in the pointing accuracy of HST with
respect to the SI apertures/field-of views.  The size of the uncertainty is 2-4
arc seconds, a rather large error compared to most of the apertures.  The
belief is that the origin of the error is in the poor FGS to FGS alignment.  A
new FGS to FGS alignment is scheduled for the week of 5 November.  Reanalysis
of earlier (poor) data is also in progress -- a bug was found in the earlier
reduction software.

AST continues to work on understanding the FGS performance and problems.  They
have developed a "9 Points of Light" proposal (scheduled for the day 323, 26
November SMS) that does a detailed investigation of focal positions within a
given FGS pickle and allows intercomparison of all three FGS pickles.

FOC continues to function well with essentially no instrument problems.

FOS has obtained their first external spectrum (Red Side) and, except for the
magnetic shielding problems, have no significant instrument anomalies.

GHRS is the most advanced of the SI in terms of OV/SV proposals completed with
all of their OV proposals and some SV proposals finished.  Unfortunately, the
same cannot be said for their SAO/ERO observations, none of those attempted
have been fully successful (see above and my previous report).

HSP is advancing instrument testing with the exception of the PMT, VIS, and POL
detectors until modifications to the bright earth avoidance angles are
resolved.

WFPC has been relatively quiet recently -- no major instrument problems have
been reported.

     Ron Polidan

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 25 Oct 90 20:33:12 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

HUBBLE TO OBSERVE SATURN'S GREAT WHITE SPOT
 
     NASA's Hubble Space Telescope (HST) is now scheduled to
observe Saturn's newly discovered white spot in early November.
The "Great White Spot," now termed the "Wilber Spot" after
amateur astronomer Steuart Wilber from Las Cruces, N.M., was
discovered September 24.
 
     According to the Central Bureau for Astronomical Telegrams,
the Wilber Spot was over 10,000 miles across, larger than the
Earth, on October 1.  Twenty-one hours later it had grown an
additional 2,000 miles.  Currently, the spot has a diameter of
over 50,000 miles, is larger than the famous "Great Red Spot" on
Jupiter and covers much of one hemisphere of Saturn.
 
     Also in the last few weeks, the spot has become even more
complex.  New spots have been seen within the main feature and
two separate white, round spots have formed.  One side of the
main spot seems darkened, as if the Wilber Spot is a raised
feature casting a shadow.
 
     Dan Green of the International Astronomical Union's Central
Bureau for Astronomical Telegrams, Cambridge, Mass., has said
that the Wilber Spot seems "almost fluorescent" in appearance.
 
     In 1933, astronomers reported a phenomenon similar to the
present disturbance.  Since that time, no other Saturnian event
has approached this magnitude.  As seen from Earth, Saturn is in
the evening sky and sets before midnight in late October.
 
     HST's Wide Field Planetary Camera will record several images
per orbit, for two orbits per day, on 3 days.  The images will be
recorded in two colors, blue and near infrared.
 
     Observing times have been chosen with considerable care
because Saturn rotates rapdily  -  a "day" on Saturn lasts about
10 hours.  An added complication is that, over time, the angle
between Saturn and the Sun, from HST, is becoming smaller, making
observations progressively more difficult.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

RE:              <<< Note 612.154 by 4347::GRIFFIN "Dave Griffin" >>>

Reminds me of the Clarke novel 2010 and what happens to Jupiter :-)
						-- Tom

    The Hubble Inst. held a press conference last Monday to release some
    images taken during the engineering checkout. A few had been seen
    before, but there were some spectacular new ones (sorry this is light
    on for detail, I accidentally erased the tape).
    
    - very clear image of Pluto and Charon; possibility of seeing surface
    features on future images
    - a local 'boring' galaxy showed a optically visible jet from it's
    center, as predicted by some theories concerning black holes at the
    center of galaxies
    - a very hot object at the center of a cluster turns out to be tens of
    thousands of stars rather than 12-20 as recent ground based images
    suggested (in a volume of approx 4 ly radius)
    
    In each case they compared the best ground based image, often very
    recent. At present they can image anything in visible light that can be
    imaged from the ground (down to 25th mag), but with 10 times more
    resolution. They had hoped to go to 28th mag, but that will have to
    wait until the cameras are replaced.
    
    Its difficult to convey how spectacular some of these images were. It
    will be worth keeping an eye on the space and astronomy rags over the
    next few months. I'm sure these will appear.
    
    gary

From: [email protected] (John Roberts)
Date: 26 Oct 90 00:35:09 GMT
Organization: National Institute of Standards and Technology

HST Update 10/22/90
Dr. Charles Pellerin and Dr. Edward Weiler
NASA Select
Selected details from broadcast

Some of this material seems to be of general interest, and I haven't seen much
of it on the list, so I thought it would be worthwhile to post a summary of
these parts:
..........................................

 - The cause of the spherical aberration seems to have been pretty much pinned
down. Elements in the null corrector (used to calibrate the shape of the
primary mirror) were spaced incorrectly by about 1.3mm. Elaborate measures
were taken to make the placement as accurate as possible, so it was not
suspected that an error of this kind could take place. To attain the ultimate
precision, measurement rods calibrated by the National Bureau of Standards
(now NIST :-) were used, and their position checked by an interferometer
(accurate to a fraction of a wavelength of light). An end cap with a hole in 
the center was placed over the end of the measurement rod of interest, to 
make sure the calibration was from the exact center of the rod. Unfortunately,
the person making that particular measurement, possibly through haste or
carelessness, got the lateral positioning of the interferometer wrong, and
calibrated from a shiny spot on the end cap, which stuck above the end of the
measurement rod. A comment was made that out of the thousands of people 
contributing to HST, this error (and the failure to detect it) was 
attributable to about three people working by themselves in an optics lab.
(I suspect those folks don't feel too good right now. :-) While in
retrospect an additional check on the null corrector would have been a good
idea, NASA still does not feel that a final integrated test for HST would have
been advisable, given the time and budgetary constraints, and the risk of
damage or contamination (I agree).

 - A graphic representation of point spread functions (target, actual, and
corrected) was shown.

 - The latest estimate is that 56% of the science that had been planned
for the near term (pre-WFPC2) can be accomplished. Since HST was already
oversubscribed by a factor of 10, now it's only oversubscribed by a factor
of 5. :-)

 - The other major problem is the jitter in the solar arrays. [It was stated
that these were provided by ESA - I hadn't realized that. Perhaps the same
company that designed Galileo's thrusters? :-) ] It is claimed that the
effect of the wobble has been overstated by the press - while the design spec
called for tracking to within the diameter of a dime at the distance from
Washington to New York, the wobble allows HST to track only to within the
diameter of a "Famous Amos" chocolate chip cookie. [No comment on choice of
units.] Most of the pictures released thus far were taken during the calm
periods in the orbit. It is hoped that the software fix (described in postings
by Ron Baalke) will be working in a few months. There are plans to replace
the solar panels in about 3 years, getting rid of the problem.

 - It is expected that WFPC2 will completely correct for the spherical
aberration. Tentative plans are being discussed to improve the performance
of the spectrographs, and perhaps perform an in-orbit repair of the Faint
Object Camera.

 - Because of atmospheric disturbance, the best images that can be obtained
from traditional ground-based telescopes (not using speckle interferometry, 
etc.) have a resolution of about 1 arc second. The HST WFPC goal was .1 arcsec,
and it is meeting this target for bright objects. It was supposed to do this
for objects down to 28th magnitude, but because of the need to compensate
for the aberration, it will only work down to about the 25th magnitude, which
is about the limit for ground-based scopes.

 - The Saturn picture was discussed, mostly repeating information given in
newspaper articles. It was mentioned that this is the highest-resolution
image ever made of Saturn from the vicinity of Earth, and that unlike Voyager,
HST can take continuing sequences of pictures to observe long-term weather
patterns. I'm looking forward to the storm pictures.

 - Because of its brightness, it is now felt that Jupiter pictures should get
pretty close to the original expected resolution.

 - Imaging Venus in ultraviolet can record weather patterns.

 - An HST / Faint Object Camera picture of Pluto and Charon is compared to the
best ever taken from the ground. The HST picture clearly has higher resolution,
showing two distinct disks with considerable separation between them. WFPC2
may be able to pick up surface features on Pluto.

 - The target resolution for the Faint Object Camera is .06 arcsec, which it
too seems to be meeting for bright objects. The image of Supernova 1987A
with its circumstellar shell was shown.

 - There are plans to add an infrared telescope to HST in 6-8 years.

 - It was speculated that the Great Observatories will probably be able to
answer the question of whether black holes exist.

 - A detailed study of gravitational lenses such as the Einstein Cross can be
used to "weigh" galaxies, and to determine the relative distance of galaxies
and quasars.
.............................
    John Roberts
    [email protected]

From: [email protected]
Newsgroups: clari.tw.science,clari.tw.space
Subject: Hubble observes distant quasar
Date: 5 Nov 90 15:31:21 GMT
  
	GREENBELT, Md. (UPI) -- The Hubble Space Telescope has made
its first observation of the chemical makeup of a faint object -- a
distant quasar that may provide clues about the early Universe, NASA
officials reported Sunday. 

	Using the telescope's Faint Object Spectrograph, astronomers
from the National Aeronautics and Space Administration, Johns Hopkins
University in Baltimore and the University of California-San Diego
observed the spectrum of a faint quasar, called UM675, about 12
billion light years from Earth. A light year is the distance light,
which moves at a speed of 186,000 miles per second, travels in one
year -- about 6 trillion miles. 

	Quasars are the brightest objects in the Universe, pouring out
energy that seems too intense to be produced from something so
compact. Although quasars were first discoverd in 1963, scientists
still understand little about how they work. 

	E. Margaret Burbidge, the University of California-San Diego
astronomer who led the team, said one of the goals of the eight-hour
observation was to look for the spectral ``signature'' of helium in
the far ultraviolet. 

	The strength of that helium signature should tell scientists
about helium abundance in the early Universe, Burbidge said. 

	``We've waited a long time. Of course, the scientific results
of the observations will only be known after intensive data
analysis,'' Burbidge said. 

	Helium is the second most abundant element in the Universe,
but scientists say the amount of the gas still appears too great to be
made by stars' nuclear fusion, which transforms hydrogen to helium.
Consequently, it has been theorized that most of the helium was made
in the ``Big Bang'' explosion that astronomers think created the
Universe about 15 billion years ago. 

	The part of a quasar's radiation that includes the main
spectral lines produced by helium cannot be picked up by ground-based
telescope. 

	But Hubble can make such observations because it operates
above Earth's atmospheric ozone, which blocks out the ultraviolet
radiation that contains the helium signatures. 

	Although the Hubble telescope capabilities have been limited
by a defect in one of its mirrors, the instrument can still conduct a
variety of research such as spectral observations until the flaw is
repaired, probably in 1993. 

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble/Saturn/Mars articles
Date: 7 Nov 90 20:54:14 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
USA Today -- 11/7/90
"Hubble To Take Look at Monster Saturn Storm"
By Paul Hoversten
 
"NASA's Hubble Space Telescope this week zeroes in on a rare giant
storm above Saturn.  Photos may help scientists better understand the
unusually spectacular phenomenon." 
 
The paper quotes Hubble astronomer Dr. James Westphal, of the
California Institute of Technology, as saying "we really don't know
what we're going to see, but it's going to be very interesting." 
 
The report says, that despite the flawed mirror, the Hubble telescope
should be able to see the storm up to three times better than
ground-based telescopes. 
 
The story says the storm is believed to be caused by the welling up of
hot ammonia gas from inside Saturn's mostly hydrogen atmosphere.  The
report quotes another astronomer, Dr. Reta Beebe of New Mexico State
University, as saying "you can get some very large bubbles and every
now and then you get a super bubble.  This is a big bubble that
punched its way through and carried warmer ammonia gas that turned to
dazzling white ice." 
 
                --------------------
 
Washington Post -- 11/7/90
"Sky Watch: Mars vs. Saturn"
By Blaine Friedlander Jr.
 
"The planet Saturn does its best to thwart the attention being paid to
that red object in the East, Mars, which hasn't been this bright in
two years." 
 
The astronomy sky watcher's special report says that Saturn is
upstaging Mars because of the recently discovered giant storm raging
in Saturn's cold but fast moving atmosphere. 
 
The article calls out viewing opportunities for Saturn and says to
look for Saturn moderately high in the west immediately after sundown.
 
Mars, though, should be the stellar star, according to the story. The
report says that those who reside in the Northern Hemisphere do not
get a chance to see Mars this bright for another 11 years and says the
Red Planet will be a minus two magnitude (normal for Venus, and very
very bright) sight until the middle of December.  The story also says
that another bright object to the right of Mars is the Taurus
constellation star Aldebaran, a red giant. 
 
The report says that Earth takes 365 days to orbit the sun and Mars
takes 687 days so it would seem the close proximity of the two planets
to each other would occur every two years.  But, the story continues,
Mars' inclination to the ecliptic plane is different from Earth's and
the "stutter-step" of celestial mechanics prevents the two planets
from being in the same close space any more frequently than once in
eleven years. 
 
The article says that Mars will be closest to Earth on Tuesday, Nov.
20, at which time the two will be 47 million miles apart. The story
says that Mars will be so bright that no light-polluted urban spot in
the Northern Hemisphere could prevent someone from seeing the Red
Planet.  The date to view Mars at its brightest, according to the
article, will be at midnight on Tuesday, Nov. 27 when the Earth-Mars
and Mars-Sun angles will be optimum. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    [I realize this is old news, but I thought I'd post it here for
    completeness.  -dmg]
    
HST CONGRESSIONAL TESTIMONY 7/10/90




                          Statement of 
                                
                       Dr. Lennard A. Fisk
                   Associate Administrator for
                 Space Science and Applications
                                
          National Aeronautics and Space Administration
                                
                           before the 
                                
          Subcommittee on Science, Technology and Space
        Committee on Commerce, Science and Transportation
                      United States Senate
                                
                                
                          July 10, 1990





Mr. Chairman and Members of the Subcommittee:

I am pleased to have this opportunity to report to the Subcommittee on the
status of the Hubble Space Telescope (HST).

When I appeared before this Subcommittee on June 29th, I reported on
NASA's preliminary assessment of tests conducted on HST over the weekend
of June 23-24.  These tests suggest that HST is experiencing what we
believe is spherical aberration, or an inability to focus light into a
single, precise point.  I want to stress that our understanding of this
anomaly is incomplete and it remains under study; however, NASA feels it
is important to maintain our policy of openness with the public and the
Congress.  As I stated at the last hearing, I am prepared to provide
whatever briefings and testimony you deem appropriate to keep you and
the other members of Congress fully informed of this situation as it
unfolds.

First, this spherical aberration is significant because it prevents Hubble
from fulfilling one of its primary requirements, namely, that "70 percent
of the total energy of a stellar image must be contained within a radius of
0.10 seconds of arc." Hubble is currently able to focus only 15 percent of
an image's energy into that same area.  
However, and let me stress this again, this aberration will not prevent
Hubble from answering the fundamental questions about the universe it
was built to investigate.  New, exciting, and unique science will be
conducted using Hubble in the near-term and over its entire 15-year
lifespan, beginning almost immediately.  Hubble will not be able to
conduct certain scientific activities in the near-term, but it will be able
to substitute significant science in a number of equally important areas. 
And over the next few years, Hubble's capabilities will be fully restored,
allowing us to recapture the science that will be deferred in the interim.

It is important to remember that NASA was established to do challenging
missions; missions that require men and machines that push the envelope
of technology to its limits.  The true test of NASA's abilities should be,
and must be, how we react when confronted with adversity; how quickly and
efficiently we overcome this problem.  I am confident that we can, and
will, overcome this.

Clearly, the first step has to be finding out the cause of this aberration. 
As I reported at the last hearing, I have established the Hubble Space
Telescope Investigation Board to investigate the cause of this anomaly. 
This Board will be a working group charged to review, analyze, and
evaluate the facts and circumstances regarding the manufacture,
development and testing of Hubble's Optical Telescope Assembly.

This Board is chaired by Dr. Lew Allen, the Director of the Jet Propulsion
Laboratory, and is composed of world-renowned experts in optical systems
and spacecraft quality control.  During this past week, the other members
of the Board were formally announced.  They are:

Charles P. Spoelhof
(Retired) Vice President, Eastman Kodak Co.

George A. Rodney
NASA's Associate Administrator for Safety and Mission Quality

John D. Mangus
Head, Optics Branch, Space Technology Division
NASA's Goddard Space Flight Center

Prof. R. (Bob) Shannon
Director, Optical Sciences Center
University of Arizona, Tucson

Dr. Roger Angel
Professor of Astronomy, Steward Observatory
University of Arizona, Tucson

The Board held its first preliminary meeting in Washington, D.C. on July 5
and 6.   A copy of the Board's public statement following its first session
is enclosed.

The second step is to continue the process of characterizing this problem
and to understand its impacts on the scientific goals of Hubble.  Our goal
will be to maximize the scientific return of Hubble in the near-term, as
well as over its 15-year lifespan.  Last week, the Hubble Science Working
Group authored a white paper which summarizes their preliminary
assessment of the impact on the science program.  With your permission, I
request that the Science Working Group's white paper be entered into the
record.

In the next few months, NASA will be working with the Space Telescope
Science Institute (STScI) and the Science Working Group to replan the
scientific program for Hubble.  As Dr. Peter Stockman reported at the last
hearing, our initial assessment is that approximately 50 percent of the
observations originally scheduled for HST are still viable.  Again, as Dr.
Stockman reported previously, part of the peer review panel that selected
HST's first-year observations will be reconvened to reevaluate the
proposals in light of Hubble's current strengths.  It is important to
remember that since there were ten times as many observations approved
originally as could be scheduled during the first year, there is little
doubt that HST will continue to be oversubscribed.  

The third step of this process will be to develop and implement a long-
term solution to the aberration.  Our preliminary assessment is that the
inclusion of a relatively small corrective mirror or lens in the front of
the second generation instruments should eliminate the scientific impact
of this aberration.  We believe that this solution should be very
straightforward and should not result in a significant cost or schedule
impact in the development of the new instruments.  NASA will also explore
accelerating the delivery of the new instruments, especially the second
Wide Field/Planetary Camera, to further minimize the scientific impact.

Remember, what we are talking about here is not 'losing science' as has
been reported in the press; but rather, altering the mix across areas of
science for the next few years.  During this interim period, we will be
deferring some significant science, primarily in visible light imaging,
while substituting equally significant science.  The bottom line is that
visible light imaging will occupy a smaller portion of on-target
observation time while ultraviolet observations, spectroscopy and
astrometry will occupy a larger portion during the first few years.  We
fully expect that after the second generation instruments have been
delivered on orbit, that all the science that is deferred will be
successfully completed.  And when examined over its full 15-year
operational lifetime, the relative distribution of observation time across
the science program will even out.

I should also note that there appears to be the potential for acquiring
additional visible and ultraviolet imaging science.  We have formed a
"tiger team" to review the potential benefits of various image processing
or reconstruction techniques.  It is thought that such techniques could
provide up to three times more resolution than the current performance
and thereby make some of the imaging science viable.  We should have some
more definitive answers on this by mid-August.

In conclusion, I would like to emphasize three points.  First, we are
committed to determine how and when the problems in the Optical Telescope
Assembly occurred which lead to the observed spherical aberration, and
how this aberration could go undetected prior to launch.  Second, we are
committed to strive forward in understanding this problem relative to its
impact on the scientific goals of the program and subsequently maximize
the scientific return of this facility both in the short term and the long
term.  Finally, we are committed to develop and implement a long-term
solution to the aberration to assure that the full potential of the Hubble
Space Telescope is realized.  I believe that we will witness discoveries
by the scientific community that will be characterized as world class.  As
Dr. Bahcall so aptly stated "When we read the history books of this
decade, we will not notice the prescription for the Hubble mirror was
slightly askew.  But we will notice that we opened major new chapters in
the understanding of the universe.  It will be an intellectual revolution."

Thank you very much.
    

    For anyone who is interested, there are GIF images from the Hubble
    Space Telescope available from: Pragma::Public:[NASA]
    
    The GIF format has viewers for just about anything with a screen, so
    view on your favorite platform.
    
    
    The two images currently available are a bland 30-Doradus, and a quite
    spectacular Saturn.
    
    
    Enjoy!
    
    - dave

    GIF is a new format to me.  Could you post a note on how to get viewers
    for it?  Thanks /jlr

For X-Windows/DECwindows see the ELKTRA::DW_EXAMPLES conference.  Look for
"GIF" in the titles.

I know the Macintosh conference has topics for the GIF viewers that
are available, I suppose the other machines have similar conferences and notes.


- dave

    See IBMPC notes conf for info on MS-DOS viewers (use VGA!). Can get
    internally from node CSCMAS: (after work hours).
                       
    I use CSHOW, great!

From: [email protected] (Ron Baalke)
Date: 9 Nov 90 23:33:49 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                            HST STATUS REPORT
                             November 3, 1990
 
     GODDARD HIGH RESOLUTION SPECTROMETER (GHRS): All phases of a fine
alignment test went well.  Analysis showed that all edges of both the large (2
arc second square) science aperture and the small (1/4 arc second square)
science aperture were scanned as planned.  That means that the star was placed
in the center of the aperture, then moved in and out of the aperture in
different directions (edges). These tests are done to facilitate future
movements of the telescope to line up a particular star in the aperture.  This
test marked the first time a star was placed in the small science aperture.
 
     HIGH SPEED PHOTOMETER (HSP): Focus and aperture map test with the
ultraviolet detector was performed successfully.
 
     FAINT OBJECT SPECTROGRAPH (FOC): Obtained three good spectra on Seyfert
Galaxy NGC 1068.
 
     WIDE FIELD/PLANETARY CAMERA (WF/PC): Completed ultraviolet flood guiding
test in which the flood mirror successfully was commanded into the flood
position.  Sixteen exposures of the Sun were taken. This is in preparation for
a later activity in which ultraviolet light will be aimed at the instrument's
charged coupled devices (CCDs), which need ultraviolet light.
 
     ASTROMETRY: A test of the parameters of binaries (a system of two stars
that revolve around their common center of gravity) was "overwhelmingly
successful."  Five good scans out of five fine locks were obtained.  From these
observations, a much better orbit can be derived on a binary star.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

RE              <<< Note 612.165 by 4347::GRIFFIN "Dave Griffin" >>>

>Sixteen exposures of the Sun were taken. This is in preparation for
>a later activity in which ultraviolet light will be aimed at the instrument's
>charged coupled devices (CCDs), which need ultraviolet light.
 
  Most likely I don't understand what this means but I thought that I
read earlier that HST would be destroyed if it was pointed at the sun
and that if it came anywhere close it would go into safe mode and the
door would close.

  Can anyone clear this up?

  George

This caught my eye as well.   Please note the preceding text which mentions
a "flood mirror".   My assumption is that there is a small mirror that can
be used to direct sunlight into the telescope assembly (though not directly
at the instruments themselves - sorta like turning on a lightbulb in a room,
but not being looking directly at it).   This is all just a guess.   The
"exposures of the Sun" were not images, but UV spectra of the ambient light
provided by the flood mirror.


- dave

    re: .162
    
    A GIF to postscript converter can be obtained from
     
    CIMTWO::DECW$PUBLIC:[XGIF.code]gif2ps.exe,.c,.opt
    
    Copy it over and then say
    
    $ gif2ps :== $[yourdir]:gif2ps
    $ gif2ps filename
    
    Saturn came out very nicely.
    /jlr

    Well,  I copied the .exe over then net and it works just fine when
    I don't specify an output file (it outputs great Postscript to the
    screen).  I've tried every possible combination of output file
    name/destination but it won't accept anything as the output file.
    All I get is a message 'input-file > output-file'.  What are the magic
    words to direct it to crank the output to a file (I've already tried
    the symbol '>', literally)?  

A typical way of reassigning output on VMS is:

$ Define/User Sys$Output file.ext
$ <Run your Program>


Please note that directs anything written to Sys$Output (stdout) to a file
for the next image that is run.  You may want to check the output file to
see that extra crud didn't get in there with the postscript file (assuming:
1. it works; 2. there's not a better way).


- dave

From: [email protected] (Ron Baalke)
Date: 16 Nov 90 16:48:56 GMT

                     HST Press Conference
 
     Next Tuesday, November 20, Hubble Space Telescope scientists will hold a
briefing on the Saturn Great White Spot (aka Wilber Spot).  New photographs
taken by HST will also be shown.  The time for the briefing is yet to be
determined.  It will be shown on NASA Select TV.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    Re: .161
    
    A couple of followups on the HST images that were made available
    in reply 161:
    
    Technical information about the images can now be obtained in 
    .INFO files (same file name as the .GIF) files.  It contains
    information like exposure times, filters, and resolution.
    
    I had mentioned that the 30 Doradus image wasn't all that thrilling.
    If you have access to any image processing programs, then play around
    with this image a bit.  A *lot* of stars are in the lower half of
    the grey scale.  If you alter the grey-scale mapping, the image becomes
    quite a sight.  I don't know if any of the programs mentioned so far
    have this capability.
    
    - dave

From: [email protected] (Ron Baalke)
Date: 19 Nov 90 02:46:45 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                            HST STATUS REPORT
                            November 11, 1990
 
     WIDE FIELD/PLANETARY CAMERA (WF/PC): Observed the Saturn white spot on
coarse track on Friday, November 9, and Sunday, November 11. On Friday, 16
exposures were taken, and all data looked good in near real time.  On Sunday,
the first set of eight exposures showed the Saturn white spot quite distinctly
and, when compared with previous exposures, the dynamics of the disturbance
were evident.
 
     HIGH SPEED PHOTOMETER (HSP): Two focus and aperture map observations were
completed.  These observations accurately determine the locations of all
science and acquisition apertures on each Image Dissector (IDT), as well as the
proper focus for each IDT beam. Also completed a Bright Earth Avoidance Test.
The test is designed to exercise a new operating method to avoid Bright Earth
occultations while the detectors are in the "operate" mode.
 
     FAINT OBJECT SPECTROGRAPH (FOS): Successfully completed internal
instrument test of the Blue Side Filter and Grating Wheel.
 
     GODDARD HIGH RESOLUTION SPECTROGRAPH (GHRS): An internal calibration test
was conducted successfully and recorded on the onboard tape recorder.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 19 Nov 90 02:49:58 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

                             HST Status Report
                             November 16, 1990
 
     NASA's Hubble Space Telescope (HST) activity progressed officially this
week from orbital to science verification, according to Joseph H. Rothenberg,
Associate Director of Flight Projects for HST at Goddard Space Flight Center.
The milestone means the operational activity of the telescope now will
devote more time to calibration of the five scientific instruments onboard the
spacecraft and less on engineering calibration of the spacecraft.
 
     "We still have some orbital verification residuals," explained Dr.
Keith Kalinowski, head of the HST Science Management Office at Goddard, "and we
will continue to eliminate these."  Among those residuals, he said, is further
diagnosis of the telescope's pointing and stability problem and an improved
calibration of instrument aperture locations relative to the Fine Guidance
Sensors.
 
     The HST, launched last April, has suffered a number of problems, primarily
a manufacturing flaw in the primary mirror that prevents proper focussing and a
"jitter" caused by the solar arrays when the spacecraft transitions from
daylight to darkness.  NASA plans to launch a repair mission to correct the
major problems with the telescope in 1993.
 
     Before the problems were discovered, officials had anticipated orbital
verification could be completed in three months.  Describing the continuing
program, Kalinowski explained, "we will start the science verification period
with a high proportion of instrument calibrations.  By June, 1991, we hope to
be devoting one-half the time to science and one-half to commissioning
activities.  As the year progresses, the science proportion will increase
and, by October, we expect to be doing 80 percent science."
 
     HST officials hope to complete science verification by December, 1991.
The science verification activity is managed by the Goddard Space Flight
Center.  Upon completion of that activity, the science operations
management will be turned over to the Space Telescope Science Institute at
Johns Hopkins University in Baltimore, which operates under a NASA contract
supervised by Goddard.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    	Yesterday, November 20, was the 101st birthday of Edwin P. Hubble.
    

From: [email protected] (Ron Baalke)
Date: 21 Nov 90 19:51:04 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
        HUBBLE INVESTIGATION REPORT TO BE RELEASED
 
     Dr. Lew Allen, Chairman, Hubble Space Telescope Optical
Systems Board of Investigation, will brief the press on the
board's findings at 2:30 p.m. EST, Tuesday, Nov. 27, 1990, at the
NASA Headquarters sixth floor auditorium, 400 Maryland Avenue,
SW, Washington, D.C.  Copies of the board's final report to NASA
will be available at the briefing.
 
     Also participating with Dr. Allen will be Dr. Lennard Fisk,
NASA Associate Administrator for Space Science and Applications,
and those members of the 
     The briefing will be carried on NASA Select television,
Satcom F2R, transponder 13, 72 degrees West longitude, frequency
3960 MHz, audio 6.8 MHz.
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (Ron Baalke)
Date: 21 Nov 90 21:34:14 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
The Philadelphia Inquirer (AP)  11/21/90
By Harry F. Rosenthal
 
Photos of Saturn show huge storm
 
"The Hubble Space Telescope has returned pictures of a
remarkable event on Saturn, a storm that has grown from an
Earth-sized white dot to a girdle around the planet with
ammonia clouds billowing 150 miles high."
 
The story quotes Cal-Tech planetary scientist Andrew
Ingersoll, "It just might me the largest atmospheric
structure right now in the solar system, outside of the sun."
 
The storm was discovered by amateur astronomers in
September when it was three times the diameter of Earth
according to the article.
 
The Hubble telescope, though hampered by a faulty mirror,
was directed a Saturn Nov. 9 and 11 and last weekend as the
storm enlarged to ring the planet with swirls and loops in a
band 6,000 miles wide, the report states.
 
 NASA Headquarter's Director of Astrophysics Charles
Pellerin said that a film would be made of the 400 pictures
take so far to depict the evolution of the "storm of the
century."
 
The article continues, saying that though astronomers do not
know the cause of the storm, Ingersoll discounted the
possibility that a comet or other celestial object struck the
planet to cause the disturbance."It has to be some sort of
internal intermittent thing on Saturn, like Saturn burped.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space
Subject: Saturn 'burps' giant storm
Date: 21 Nov 90 01:11:10 GMT
  
	WASHINGTON (UPI) -- Saturn has apparently ``burped'' a
gigantic storm that spewed a huge cloud of ammonia gas crystals that
has encircled nearly the entire mammoth planet, scientists said
Wednesday. 

	The unusual storm was first spotted in September by amateur
astronomers, prompting excited scientists to convince NASA to allow
them to use the Hubble Space Telescope to photograph the area in
detail earlier this month. 

	``It turned out it became something very special,'' said James
Westphal of the California Institute of Technology in Pasadena, Calif., 
at a news conference at NASA headquarters where the images were released. 

	The storm, which is about 150 miles above Saturn's normal
upper atmosphere, was about triple the diameter of Earth when it was
first detected on the ringed planet's equator in September. 

	The images show the storm is spreading eastward at about 1,000
mph and has stretched nearly completely around the planet's equater to
a size of about 200,000 miles -- or about 10 times the size of Earth,
the scientists said. 

	The size of the storm makes it the ``largest atmospheric
structure right now in the solar system outside the Sun,'' said Andrew
Ingersoll, a professor of planetary science at Caltech. 

	Ingersoll said he was uncertain how or why the storm formed
but that ``it really has to become sort of internal, intermittent
thing on Saturn.'' In other words, ``Saturn burped,'' he said. 

	``Why it should wait so long to burp, I don't know,'' he said,
noting that the last time anything similar was spotted on Saturn was
in 1933. 

	``It's sort of hard to see why things should build up and then
burp so magnificently,'' he said. ``But that's what it did.'' 

	Because it is summer in that part of Saturn, Ingersoll
speculated heat from the Sun may have helped trigger the storm's
formation from hydrogen and helium gas and liquid from the deep
``primordial'' interior of Saturn, which is a ``bubbling cauldron of
liquid and gas,'' he said. 

	``In some mysterious way, which I do not have a clue as to,
Saturn burps...perhaps in the summertime,'' he said. ``Just the
changing heating of the atmosphere changes the stability of the
different layers'' of the planet. 

	The scientists hope to continue to study the storm to learn
more about it and Saturn itself, which apparently is more turbulent
than previously thought, the scientists said. 

	The storm, which resembles Jupiter's 300-year-old Great Red
Spot in some ways, may eventually evolve into an ancient giant storm
like that, Ingersoll said. ``I have my fingers crossed,'' Ingersoll said. 

	Charles Pellerin, director of NASA's astrophysics division,
said the 64 images of the storm taken Nov. 9 and Nov. 11 and about 250
more pictures captured by the telescope's wide field/planetary camera
last weekend demonstrate the value of the $1.5 billion instrument
despite its flaws. 

	``Hubble is becoming a mature explorer,'' he said.

	About a month after the telescope was placed into orbit above
Earth last April, NASA discovered one of the telescope's mirrors was
apparently misshapen, blurring its view of the heavens. 

	NASA plans to correct the problem when one of the telescope's
cameras is replaced in 1993, and has said the machine can still do
valuable research in the interim. 

It mioght just be my own ignorance, but who is one to display the GIF files?
I downloaded the SATURN picture, but I can't get UTOX to display it (UTOX 
supposedly knowns what to do with a GIF file) or on RAGS (is GIF a form of
bitmap?)

					-**Ted**-

From: [email protected] (Ron Baalke)
Date: 26 Nov 90 23:14:36 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

Hartford Courant -- 11/26/90
"NASA, Perkin-Elmer Share Blame for Hubble Flaw"
By Robert Capers and Eric Lipton

"NASA and a mirror manufacturer share the blame for a flaw 
that prevents the $1.5 billion Hubble Space Telescope from 
focusing clearly, a NASA panel has concluded after a five
month investigation."

The New England paper, the closest metropolitan paper to the
former Perkin-Elmer plant where the mirror was ground,
says that to some extent the failure to detect a flaw polished
into the primary mirror in 1980 is a product of the same 
management climate that led to the fatal explosion of the space 
shuttle Challenger.

The paper says that conditions then discouraged engineers 
from bringing potential problems to their superiors at NASA 
and at Perkin-Elmer, in Danbury.

The paper quotes an investigation team member, John 
Mangus, as saying "the culture has to be encouraged where
you don't shoot the messenger.  People don't like bad news, but
what they like worse is not to be told about the problems.  I
know it has occurred on many of NASA's projects."
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    For those of you who would like to see the HST pictures of Saturn's
    White Spot, those taken on November 9 and 11 are shown in the November
    24 issue of "Science News". They are B&W but show impressive details.
    
    				Drew
    

From: [email protected] (ROB STEIN, UPI Science Editor)
Date: 27 Nov 90 23:29:59 GMT

	WASHINGTON (UPI) -- NASA and the company that built the Hubble Space
Telescope share the blame for failing to detect the flaw that crippled
the instrument's powers, a NASA report concluded Tuesday.
	Workers at a Perkin-Elmer Corp. facility in Danbury, Conn., had at
least three major chances to find the defect before the telescope was
placed into orbit in April, but the employees wrongly dismissed the
signs, the report said.
	In addition, employees in Perkin-Elmer's optical division failed to
bring the signs of trouble to the attention of top company officials or
anyone at NASA, said Lew Allen, who led a team that investigated the
embarrassing flaw for NASA and issued the report.
	However, NASA also must accept responsibility because the agency was
in charge of the project and oversaw the work, Allen said.
	``Perkin-Elmer should have not have allowed a situation for those
inhibited communications to exist. NASA had every right to expect that
Perkin-Elmer would have done a better job than this,'' Allen said at a
news conference.
	``On the other hand, it is fundamentally NASA's responsibility as the
government agency to get this done. NASA should have been aware of what
was happening at Perkin-Elmer,'' he said. ``I think you have to say each
... has to bear responsibility.''
	Sen. Al Gore, D.-Tenn., who held hearings to investigate the
telescope's defect, said the report ``makes crystal clear'' the need for
NASA to ``continue its efforts to strengthen testing and quality control
efforts.''
	Lennard Fisk, NASA's associate administrator for the Office of Space
Science and Applications, said it was ``premature'' to say whether the
agency would take action against the Perkin-Elmer business, which is now
called Hughes Danbury Optical Systems Inc. after a General Motors Corp.
subsidiary bought it. Hughes Danbury had no immediate comment.
	Fisk acknowledged the mistakes that led to both the 1986 explosion of
the space shuttle Challenger and the Hubble defect had some
similarities. But Fisk noted that Hubble's problem occurred 10 years ago
and that the agency had taken many steps since then to avoid such
mistakes.
	``Considerable effort has been made to promote communication,'' he
said.
	Allen noted his panel checked whether similar problems exist with
another NASA project underway at Hughes Danbury and found that
improvements had been made.
	Although the telescope can do valuable research despite its flaw,
NASA plans to correct the defect in 1993 by installing a modified camera
on board. The repair will cost between $40 million and $50 million, Fisk
said.
	The long-awaited $1.5 billion telescope was expected to revolutionize
astronomy by being able to study the universe in greater detail than
ever before through its advanced optical system and perch 381 miles
above Earth.
	But about two months after the instrument was placed into orbit, NASA
was shocked to discover the telescope's supposedly perfect primary
mirror was misshapen, preventing the telescope from bringing starlight
into sharp focus.
	An embarrassed NASA formed the six-member panel to investigate the
defect headed by Allen, director of the Jet Propulsion Laboratory in
Pasadena, Calif.
	The panel discovered the problem apparently was caused when a Perkin-
Elmer worker incorrectly set a device called a reflective null
corrector, which was used to measure the mirror while it was being
precisely ground.
	Employees had indications there was a problem when they had to
install washers in the device to compensate for the faulty setting, and
twice more when tests with other instruments, called refractive and
inverse null correctors, indicated the mirror was shaped wrong.
	But the warning signs were ignored because the reflective null
corrector was considered the most accurate of the three testing devices,
the panel found.
	``The Perkin-Elmer plan for fabricating the primary mirror placed
complete reliance on the reflective null corrector as the only test to
be used in both manufacturing and verifying the mirror's surface with
the required precision. NASA understood and accepted this plan,'' the
report said. ``This methodology should have alerted NASA management to
the fragility of the process and possibility of gross error.''
	In addition, Perkin-Elmer tended to operated like a ``closed shop''
in which NASA overseers were not allowed to actually watch employees
work, Allen said.
	The report also cited pressures over cost and time that deflected
attention from the mirror's construction.

HST INVESTIGATION STATEMENT

      OPENING STATEMENT AT A BRIEFING BY THE HUBBLE SPACE TELESCOPE
                OPTICAL SYSTEMS BOARD OF INVESTIGATION
                            Nov. 27, 1990
                           Time: 2:30 p.m.
       Location: NASA, 400 Maryland Ave. SW, sixth floor auditorium

     DR. LENNARD FISK:  As you will recall, last June during the
initial check out procedure of the Hubble Space Telescope, we
discovered to our dismay that the mirrors exhibit a condition that is
known as spherical aberration, and that that results in Hubble's being
unable to meet one out of the more than 50 or so principal or level one
specifications.  And in particular, the specification that's not met
is--if you have a point source with Hubble, a point source of light, 70
percent of that light should be focused to within a circle which is a
tenth of an arc second in radius--if you like, a tenth of an arc second
is a dimension approximately one thirteenth millionth of the
circumference of a circle.

     Now, with the spherical aberration, only about 20 percent of the
light is focused in the required tenth of an arc second circle. And
this results in Hubble's use being somewhat restricted in being able to
see very faint and very low contrast objects.

     Now, whenever you have a level one specification that is not met
on orbit, NASA undertakes a formal review, and so accordingly in early
July, I asked Lew Allen to chair a review board to determine three
things:  First of all, what caused the spherical aberration; secondly,
when did the problem occur; and then, finally, how did it go undetected
prior to launch.

     We placed on the board noted optical experts from around the
country--there's Doctors Angel, Mangus, Shannon and Spoelhof, and in
addition we had George Rodney, who is the associate administrator for
quality and safety here at NASA.

     Now, clearly we were interested in understanding what the causes
of the spherical aberration were for essentially two reasons:  First,
as I mentioned, when we don't meet a level one spec, we want to know
why that was the case.  But perhaps more important, we are, of course,
determined to fix Hubble, and to bring it back to its full capability,
and knowing what the cause of the spherical aberration is is very
helpful in determining these fixes.  And in that regard the Allen board
is working in concert with the other board that was appointed at that
time, the HST Independent Optical Review Panel, which has been advising
us on ways to maximize the on orbit performance of Hubble.

     I've been very pleased with the rapidity, the thoroughness and the
decisiveness with which the Allen board has answered the questions that
we asked.  Lew will review for you in a moment his conclusions about
the spherical aberration.  I don't think they're going to come as a
surprise to you, because the board, of course, has had press releases
at the end of its of its four meetings.  They've had interim press
releases which reveal the causes of the spherical aberration.   The
report that you have in front of you is simply the documentation of
these earlier findings, and it closes out the board's activities.

     We're going to spend, presumably, the next few minutes, and from
the size of the audience here, perhaps more than a few minutes,
reviewing the events that took place a decade ago that led to the error
in the primary mirror of Hubble.  But as we do so, we should always, of
course, remember that even with this spherical aberration, Hubble is
unsurpassed in its capability as an optical telescope.  There is no
ground-based telescope which has the combination of the resolution and
the sensitivity of Hubble.  And, fortunately, most  of the exciting
objects in the universe have sufficient contrast and sufficient
brightness so that the spherical aberration is just a minor
inconvenience in observing that.

     Fortunately, also, the spherical aberration was ground in with
great precision, and so it is a very straight forward thing to correct,
and we will make those corrections in 1993 to bring Hubble back to its
full capability.  Lew?


    DR. LEW ALLEN:  I might start by mentioning the Independent Optical
Review Group, which Len referred to, since it formed the basis for the
understanding of the performance of the telescope in orbit.  The error,
the spherical aberration error, has been detected on the wide
field/planetary camera, the faint object camera, and the wave front
sensors.  So, there were several sources of data to examine.

     The review group found that this error, as seen on orbit, is best
explained by an incorrectly shaped primary mirror, and is not required
for the observations that are seen so far to presume any errors in the
secondary mirror.  So this clearly enabled us to focus our attention
rather quickly to the primary mirror.

     I'd like to add to Len's statement about the panel membership,
that Robin Lawrence of the European Space Agency was an observer to the
board, and the reason for that is, of course, that he is responsible
for the faint object camera, one of the very important instruments on
board the telescope.

     Because of the nature of the aberration, that is, the very
particular character of spherical aberration, we were fairly quickly
able to identify that by far the most likely source of the error was in
the test equipment which was used to measure the mirror during its
fabrication and for its acceptance purposes. So we focused in on that
really rather quickly.  In addition, that was helped by the fact that
other Ritchey-Chretien telescopes made for ground observations have had
problems with spherical aberration and in general were caused by
difficulties in the test equipment.
 
    Our investigation began with impounding all of the equipment in
the data at, then Perkin-Elmer, now Hughes Danbury Optical Systems, and
we were then aided in the subsequent examination of that impounded
equipment and data by being able to determine that the test equipment
was undisturbed in the intervening ten years.  And if I could have the
first view graph, please, I'd like to show you the evidence of that.

     (View graph is shown.)

     This represents the interferogram as observed with the item of
test equipment which tests the primary item of test equipment, that is,
the reflective null corrector which is used to test the primary mirror,
is itself tested by what's called an inverse null corrector.

    And we have the interferogram, which is on the left of what you
see, being an interferogram that was taken in the time period of
interest--that is, 1981--and the one on the right being an
interferogram taken in 1990.  As you'll see, these two are essentially
identical.  What that means is that the reflective null corrector, the
device which we're going to look at more closely in subsequent
examinations, and its inverse null corrector have essentially been
unchanged to a high degree of accuracy in the ten years since their
measurements were really made.

     So with that understanding, then, we were able to proceed to try
to figure out what was wrong with this test equipment.
 
    Now, the reflective null corrector is a device which in effect
projects the desired shape of the mirror on to the actual mirror in the
process of its fabrication.  Then by reflecting light off that mirror
back up through the reflective null corrector, one can obtain an
interference pattern which tells you how close you are to the desired
figure, and the design of this reflective null corrector is shown in
this particular figure.
 
    Now, the Perkin-Elmer proposal to NASA for building the Hubble
telescope stated very clearly that to obtain the precision which NASA
desired that it was necessary to design a new type of null corrector,
one that had not been used in making previous telescopes--that would be
this reflective null corrector--and that it itself would be measured to
very high precision in order to be sure that it was certified to
provide the correct figure for the mirror.

     NASA understood that element of the proposal.  There were other
ways to go about this particular project, but it was a--although a
somewhat fragile philosophy of fabricating the mirror, it was
nevertheless an acceptable one.  But it did require that a great deal
of care be taken in measuring the spacing in particular of the elements
of this reflective null corrector.

     Now, the null corrector was certified by Perkin-Elmer and then was
used to measure the shape of the mirror both during fabrication, at
various steps during fabrication, and then finally at the point where
it was accepted before coating, and then at the point where it was
again accepted after coating, to ensure that the coating process did
not influence the figure.
     If I could have the next vuegraph, please.  This shows the
interferogram of the finished primary mirror.  The way the
interferogram is made is a deliberate tilt is put in one of the
elements in order to get a number of fringes, and then the shape of
those fringes is measured in this interferogram.  The fact that these
fringes are very straight indicates that the mirror was fabricated very
precisely.  As a matter of fact, it is of a degree of precision which
probably exceeds any other mirror of this size that has ever been made.
     Now, there is no question, then, that the precision of the mirror
was very good.  The problem then has to arrive because the shape to
which it was made so precisely was inaccurate.  And that inaccuracy can
come because of an error in the spacing of the elements of this
reflective null corrector. The plan which Perkin- Elmer had made
required that those elements be measured to a precision of about 10
microns.  That's three ten-thousandths of an inch.

    And if I could have the next vuegraph, I'll show you how they plan
to do at least one of the several spacing measurements.

     This figure shows that they were going to use--they did use--a
very precisely measured invar rod.  Invar is a material which doesn't
change its dimensions with changes in temperature and therefore is a
very good measuring material. This invar rod was manufactured to be a
very accurate length. Then the invar rod was positioned in the
assembled reflective null corrector such that the upper point of that
rod, as you see in this particular figure, was located with an
interferometric device to be at the center of the radius of curvature
of the lower mirror.  Then the field lens, which is shown at the bottom
of the figure, was brought up until it just contacted that rod.  And
one could observe it just contacting with very light pressure by seeing
a variation in the interference pattern that was being observed at the
top of that rod.

     Now, that procedure was carried out, but it had a problem with
it.  And if I could have the next vuegraph, please. And the problem was
that in order to center the beam of the interferometer on the rod, a
field cap was built.  The field cap had no purpose other than to ensure
that the beam went to the very center of this curved end of the rod in
order to get the measurement to be very precise.

    That end cap had been coated with an anti-reflective material so
that if the beam struck the end cap itself it would not give fringes.
But in fact some of that anti-reflective material had been removed from
around the hole--and I'll show you that in just a moment.  And what
actually happened was that the interferometric beam was
located--instead of being in the hole, on the edge of the hole, and so
the fringes were obtained from a position on the end cap which is 1.3
millimeters away from the desired point, as shown in this figure.

     When this measurement is being made, the operator can't see this
particular set-up so he doesn't know this is happening except by the
behavior of the fringes that he sees. And his procedure was not to
expect there to be fringes except when he was in the hole. Now, if we
can show the next vuegraph, please.
 
    And this is a photograph of the end cap.  And what you'll notice
is that the anti-reflective material has for some reason that we don't
know been removed from a region that is close to the hole but around
the hole.  That probably occurred because when they coated it, it
probably got some of it in the hole; when they poked it out of there it
probably broke it away a little bit from the edges.  But we're not
sure.

     Now, clearly what I've described is a hypothesis on our part, that
is, we don't know that this is exactly what occurred.  But it's a very
plausible one.  We do know that the error is there, and the error is
just what you would expect from the procedure that I've described.
Furthermore, to verify that this is a highly plausible scenario, we
reset up the apparatus and had an operator again make fringes, as he
would have 10 years ago, and indeed he made the same mistake.  But it
was clearly a mistake that was not only possible, it was one that was
likely to be made in the way that the particular apparatus was done.

     Therefore, our conclusion is that the error is a spacing error in
the reflective null corrector, and the error was caused by a procedural
error in how this particular spacing measurement was made.

     Now, the next question that Dr. Fisk asks us is, now that we
understand the error and how it probably occurred--is why wasn't it
detected prior to launch?  And the answer to that question is not a
particularly happy one, because we are obliged to go through the
various ways that it should have been detected before launch.  And I'd
like to list those very briefly as they are listed in the report.

     First of all, when the spacing error was made, the field lens
which was being brought up to the bottom of that metering rod did not
have enough travel in the adjusting screws. So they needed to add
washers to that particular adjustment to space it away.  That in itself
should have alerted people to the attention that something was
different than the designers had intended, because clearly the
designers had designed this in such a way that there would not be a
need for any unexpected washers to be added.

     We were told in testimony that the addition of those washers
required a material review board to be convened to dispose of that
variation in procedure.  We could not find in the remaining
documentation the evidence of that material review board, so we really
don't know whether that actually occurred or not.

     But, in any event, either it was not properly examined or it was
disposed of improperly, but the first opportunity to catch this would
have been when those washers were added.

     Now, in addition, when those washers were added, the screw and the
bolt and the washers and all should have been staked, that is, a
procedure in which the position of the bolt is fixed so that it will
not jiggle or be misadjusted later on. These particular bolts and nuts
were not staked.  That was an error in procedure which may or may not
have been treated by that material review board.  I doubt it.  But it
was another case to indicate that somewhere in the process of
assembling this, things were done too hastily perhaps, but without
adequate review.

     Now, there were two other major opportunities to have caught this
error, and I will describe them both.  But in each case what you will
hear me say is that the discrepant data was examined within the optical
operations division of Perkin-Elmer, and was discounted because of a
high confidence in the reflective null corrector which was regarded as
a certified test device and a lower confidence in the other instrument
which was revealing the inconsistent data, which was regarded as an
uncertified device.

     Now, the reasons for this were that the two devices I'll talk
about--the refractive null corrector and the inverse null
corrector--both were assembled with presumably less rigorous procedures
than was the reflective null corrector, and were known to have some
errors in their assembly, and therefore the data from them was
discounted.  This turns out to have been a mistake, because we had
commissioned to have done an error analysis of each of those devices
based on the as-built data, and found that while indeed they were
inaccurate to some measure the inaccuracy was substantially less than
the effect that was actually being observed.  So the data from them
should not have been discounted.  Now, if I can have the next vuegraph,
please.
 
    This shows an interferogram which is obtained by using the
refractive null corrector with a test plate in the center of the mirror
for the purpose of measuring the vertex radius.  Now, this test from
the very beginning was to be used in the manner in which only the very
central region of what you see there in that interferogram was to be
examined.  By examining the way the fringes compare in the inner zone
of the primary Hubble mirror with the test plate, which is now filling
the hole of that primary mirror, one was able to determine the vertex
radius and determine if that was correct.  This is important, among
other things, for the focused position of the telescope.  But the
refractive null corrector incidentally obtained an interference pattern
of the entire mirror, as you see.  And that interference pattern shows
a spherical aberration.  Since the purpose of the test was not to
determine the shape of the mirror, this was in part ignored, it did
cause some of the technicians at Perkin-Elmer concern that something
was wrong somewhere, and the testimony that we had indicates that that
concern was examined in some depth by the people in the optical
operations division of Perkin-Elmer and was disposed of by saying, no,
the reflective null corrector is the instrument that's correct, not the
refractive one, and therefore the discrepant data was then discounted.

     Now, there was another opportunity to have found this error, which
I'll show in the next vuegraph, which is similar to one that I showed
earlier to convince you that the reflective null corrector had not
changed in 10 years.  This is a picture of the interferogram that's
obtained when the reflective null corrector is tested against the
inverse null corrector, this device which is swung in from time to time
to verify that the reflective null corrector has not changed its
characteristics nor its alignment with its associated interferometer.
This was done periodically to make sure that everything was aligned
correctly.

     Again, the purpose of this particular measurement was just to
verify the alignment. Therefore, the operator was not told to look with
any care at the fringes that were seen here, and in fact in general did
not. Nevertheless, images were taken--interferograms were taken of the
pattern that was seen, and those interferograms clearly show again that
there's fear of collaboration somewhere in the system.  Once again,
that seems to have caused concern among some of the technicians
according to the testimony that we received.  Once again, the material
was examined by the optical operations division's people at
Perkin-Elmer and again was discounted because it was known that the
inverse null corrector had some errors in it.  That discounting was
incorrect because those errors were not as large as the sphere of
collaboration which is seen in this interferogram.

     Now, when we have gone back now obviously with the benefit of
hindsight and examined all of this information for consistency, we find
that it's all consistent; that is, the inverse null corrector was
showing that there is an error in the reflective null corrector.  The
refractive null corrector was showing that there's an error in the
reflective null corrector. And the on-orbit data shows that there is an
error in the reflective null corrector.  And all of them are consistent
in both magnitude and sign.

     Now, there were other cases where the error might have been
found.  For example, phase one of the polishing of the mirror was done
at the Wilton facility of Perkin-Elmer, and when it was transferred
there was an opportunity to compare the data as measured with the
refractive null corrector, with the reflective.  We've looked back at
that data and it does show some inconsistencies, but it's confused by
some other circumstances associated with the transfer, so we concluded
that it was probably unreasonable to have found the error at that
point, although careful analysis might have discovered it.

     Once again, very late in the process, in order to check focus, a
measurement was made, a so-called sub-aperture test, through the entire
system, that is, the assembled primary and secondary mirror, as the
whole optical telescope assembly was put together.  This was just for
the purpose of determining focus. But if it had been done very
carefully, it might have revealed this error.  But we've looked at
those interferograms. They are confused by the fact that the telescope
at this point is lying on its side and there's a good deal of gravity
distortion.  So we concluded that it's probably not reasonable to have
expected them to have seen the error at that point.

     But nevertheless there were at least three cases where there was
clear evidence that a problem was developed, and it was missed all
three times for reasons that we have described.

     Now, we can discuss a little bit some of our opinions about the
kind of things that could have caused this discrepant data to have
missed (sic), and I'll just comment on a few of them very briefly.  The
project was on severe cost and schedule problems at the time.  The
attention of management was clearly focused on other matters and there
had developed a good deal of confidence in the fabrication of the
primary mirror, and therefore it simply did not come to the top
management attention.

     There were a number of review mechanisms that were set up, and
these review mechanisms did not penetrate deeply enough into the
fabrication processes within the optical operations division.  We're
not entirely clear as to why they did not. There were review boards
that were--one of Perkin-Elmer and one of NASA--which had on them very
competent people in the use and fabrication of telescopes, but they did
not penetrate deeply enough into the fabrication process to realize
that there was discrepant data and there were some people in the
optical division that were concerned about that data.  We think that
that was probably because the optical operations division operated in a
closed-shop environment, that is, they were skilled craftsmen and
apparently felt that they operated best if they didn't have much
review, and therefore restricted external observation of their
processes except when they were near the final stages and were able to
show the final interferograms.  It is very clear that the optical
operations division people did not at any stage, at least according to
the testimony we received, present this discrepant data, the fact that
they were seeing some of these problems, to either their own management
or to either--or to NASA management--or to either of the two technical
advisory groups that were formed.  So the result of that was that this
discrepant data and the manner in which it was dispositioned did not
appear to reach the attention of anyone outside of the fabrication
division.

     Now, there are a number of lessons to be learned from this.  We
have tried to describe a few of them in our report, and I think they
are self-evident from what has happened.  I might add a couple of
points.  One of them is that a rather lengthy examination was done in
conjunction with our board examination under the leadership of George
Rodney which examined the adequacy of the quality assurance procedures
of both Perkin-Elmer and NASA.  The conclusions from that, which have
many sub-features to them, some of which are summarized in the report,
is that the quality assurance procedures that were established,
accepted by NASA and established at Perkin-Elmer, were adequate to
raise issues but did not.  There are several reasons for that, but we
think the main reason is the same one that inhibited review of the
activities within the optical operations division, and that is this
tendency to operate as a closed shop.

    That is, some of the very particularly sensitive measurements were
made in an environment where the measurement was very sensitive to
either vibration or dust, and therefore the technician making the
measurement did not allow the quality assurance person to actually
observe the measurement as he was making it.  Instead he had the
quality assurance person verify the procedure, but was obliged to
accept the technician's statement as to what the actual results were
and was not able to actually observe the procedure as it was taking
place.  That possibly could have been a contributing cause to not
catching some of these errors.

     Now, before concluding, I would like to add one point, and that is
before our board disbanded, Dr. Fisk ask that we take a day and review
the Hughes-Danbury optical systems division company, the work that is
under way for the advanced X-ray astronomical facility, because it,
too, requires the fabrications of mirrors to an unprecedented
accuracy--different kinds of mirrors for a different purpose, that is,
for observing X-rays, but nevertheless a very challenging job and one
in which one could imagine similar circumstances impeding the
confidence one had in that.  We did make such a review and asked
whether the problems that we believed led to the Hubble error existed
at the present time in the AC-staff (phonetic) fabrication process. We
concluded they did not.  For a number of reasons that have stemmed out
of changes in NASA and the contractor over the last 10 years, quite the
opposite was the case, that is, there had been very major efforts made
at Perkin-Elmer to ensure that the internal system of communications
was such that any technicians with concerns about how the process was
going had an adequate opportunity to raise those concerns to the higher
levels of Perkin-Elmer, now H. Doss management.  And we were satisfied
that that was indeed the case.  In addition, the advisory groups which
are set up in the case of AC-staff were indeed aware of their
responsibility to observe the process on the floor and see the actual
raw data as it was coming in.  And we saw evidence that the review
groups did get on the floor with the technicians and were understanding
of the in-process data, something that did not occur during Hubble.

     And then, thirdly, the management set-up is different in that
there is an integrating contractor, TRW in this case, who has a
responsibility to assure the integrity of the entire system, but that
process also causes an additional review to be made over the adequacy
of the fabrication.

     And then finally, in the case of the AC-staff, there is a
requirement for an end-to-end test which is to be done with a source of
X-rays to confirm that all of the process is working properly.

     So for all of those reasons we believe that there were very
stringent technical challenges in the AC-staff program but that the
same kind of situation did not cause that caused the problems in
Hubble.

     Now, I've reported the results of the investigation in the report
which you have, and then amplified it in some oral discussions with Dr.
Fisk and Admiral Truly, and they of course have to decide what actions
need to be taken from here on.  But at this point I'd be pleased to any
questions that you may have.

Controllers of the Hubble Space Telescope (HST) expect to resume Science 
Verification on late Sunday, Dec. 9, after the failure of a redundant gyro 
placed the spacecraft in RsafeS mode for several days.

	HST entered "safe" mode Monday, Dec. 3, at 9:08 A.M. EST.  The 
"safing," officially called a software sunpoint safemode, occurred shortly 
after the spacecraft had passed through the deepest part of the South 
Atlantic Anomaly, the area over which the Earth's radiation belts pass 
relatively close to the surface. HST  had just completed a successful guide
star acquisition. 

	First indications of a problem began at 8:05 A.M., when controllers
noticed some oscillation in the spacecraft.  A few seconds later,
the spacecraft lost lock on the guide star, and the gyros shifted
operating modes.  At the same time, the spacecraft began a
high roll rate (60 arc seconds per second).  The gyros sensed
something was wrong, causing the software to turn off the No. 6
gyro and put the spacecraft into a three-gyro configuration.  The
spacecraft has six gyros, but only uses four actively for normal
operations.  At the time of the incident, gyros 3, 4, 5 and 6 were in
operation.

	At 8:13 A.M., a scheduled loss of signal with the Tracking and Data 
Relay Satellite (TDRS) occurred and, at 8:24 A.M., the expected acquisition
of signal did not occur, indicating that either the HST antennas were not 
pointing at TDRS or the spacecraft had entered safe mode.  Data that was 
later replayed indicated that at 9:08 A.M., the spacecraft had failed a
battery rate of charge test, and the HST autonomously went into the
software sunpoint safemode, ss it is designed to do.  

	Preliminary failure analysis indicates the spacecraft probably lost
its null signal to gyro 6 and, therefore, probably suffered a failure in
the circuitry in the gyro 6 electronics control unit or in the wiring
between the two. Both units are Orbital Replacement Units and can
be replaced on the 1993 servicing mission.  

	Attempts to reset gyro 6 on Tuesday, December 4 were
unsuccessful.  About 8 P.M. Tuesday, one of the two backup gyros, 
No. 2, was activated.  It has been introduced into HST's control
system and recovery from safe mode has begun.  Appropriate
housekeeping and alignment activities related to the activated gyro
will take place over the next few days, and Science Verification
activities are expected to resume Sunday, December 9.

	Goddard Space Flight Center has established a formal failure
review board to define the most probable cause of the failure and
to provide recommendations concerning further actions.  Planning
has begun to permit the inclusion of a replacement pair of gyro ORUs on 
the 1993 servicing mission.  

Status of HST instruments and other issues:

	Goddard High Resolution Spectrograph (GHRS)--Investigated the
chromosphere of Alpha Tau, brightest star in the constellation
Taurus.  Though larger and brighter than our Sun, it is cooler. 
Purpose of the test was to observe emission lines from ionized
carbon at a wavelength near 2325 angstroms.  

	High Speed Photometer (HSP)--A focus and aperture mapping test
was conducted successfully.

	Faint Object Spectrograph (FOS)--Conducted a Red Side Absolute
Photometry test which ran "perfectly" on the second of three
targets.  The team is looking for reasons this test works on the
Red Side but not on the Blue Side, referring to the blue and red RendsS of
the spectrum of visible light.  

	Wide Field/Planetary Camera (WF/PC)--Completed photometry of
a Large Magellanic Cloud Young Cluster.  Test provides realistic
data for stellar photometry over a range of crowding.

	Astrometry--A Science Assessment Observation (SAO) for
duplicity among Hyades' stars was performed with no apparent
problems.

	Spherical Aberration--Tests required by the Hubble Aberration
Recovery Program (HARP) to characterize fully the Optical Telescope
Assembly (OTA) were completed just before the spacecraft entered 
safe mode.  From this information, the final optical prescription
for the replacement instruments on HST will be derived.  The
prescription for the Wide Field/Planetary Camera-2 is due at the
Jet Propulsion Laboratory in Pasadena, CA, by the middle of
December.

	Solar Arrays--On Nov. 28 controllers at Goddard uplinked software 
known as the Solar Array Gain Augmentation (SAGA), designed to 
attentuate the 0.1 Hz disturbances being transferred into the body of the 
HST by the European Space Agency- developed solar arrays.  The 
disturbance, more commonly referred to as a "jitter," takes place when the 
spacecraft moves from daylight to darkness and vice versa.  The SAGA 
software is aimed at offsetting the vibration in the spacecraft, which was 
making the gyros switch operating modes and causing the HST to lose lock 
on its guide stars.  Initital testing of the SAGA software was encouraging. 

In tests of up to 11 hours, HST's gyros had not switched from the low to
the high mode.  Significant damping of the 0.1 Hz disturbance was noted, 
although a small oscillatory disturbance in the roll axis was observed in
an activation just prior to entering the safe mode.  That disturbance is
being evaluated. March continues to be the target date for all software
efforts to correct the solar array jitter."

    For an excellent review of the status of the Hubble Space Telescope,
    along with some great pictures, see the January 1990 issue of Sky
    & Telescope.
    
    Photos include a 22-arc-second field of M14 (with ground comparison)
    from the FOC, Saturn, Pluto & Charon, a Seyfert galaxy, Comet Levy,
    and a spectrogram of Chi Lupi from the GHRS.
    
    Discussion and statistics of the various vibrations that are still
    occurring are also presented along with discussion about how they may
    be fixed.
    
    - dave

    re: .185
    
    I found the planetary pictures the most impressive.  The Saturn photo
    (processed to remove spherical abberation) was exceeded in quality only
    by the closeups taken by Voyager (which S&T included).  The photo of
    Pluto and Charon acutally resolved the two!  I wonder if this super
    camera would show astronaut's footprints on the Moon?
        John Sauter

In a way, I'm beginning to understand the disappointment (sadness/outrage)
of those scientists who are close to the HST and have waited so long for it.

When you see what this telescope is capable of doing when it isn't meeting
one of it's main requirements, there's quite a bit of pain there -- and it
seemed to have all been caused by simple human frailty.

On the bright side, it appears that this observatory can be repaired and
it would seem worth the money to do so.


- dave

  Did you mean January 1990 or is it January 1991?

  I doubt that they would see footsteps but could the HST see equipment
left behind by the Apollo missions? It seems that they would have to have
about a 20 foot resolution at 250,000 miles with plenty of light. Is that
within the specs of HST?

  George

    The article is in the January 1991 issue---the one just out.
    
    I don't know how much magnification they can add to the optical path of
    HST before the light hits the CCDs.  I think they were planning on
    resolving down to 0.1 seconds of arc, so that would mean (if my
    arithmetic is correct) about 200 feet at 250,000 miles.  If they've
    got the equivalent of a 10x magnifier available in the optical path
    they might get a piece of equipment as a single pixel.
    
    I don't think light is a problem.  It's a 2.4-meter telescope, and
    the moon gets as much sunlight as the Earth, on the average.  They
    might even have to stop down the primary.
    
    Maybe it's not possible, but I like the idea of getting a look at
    the cast-off Apollo equipment.
        John Sauter

    Re: HST seeing equipment on the Moon
    
    	Put the brakes on that idea, guys. First, HST is not suppose to
    look at the Moon. It is too bright and could damage some of the
    sensitive detectors. Assuming for the moment that it COULD look at the
    Moon, it could only see features as small as about 250 to 300 feet.
    That simply is based on the diffraction limit of the optics used and no
    amount of additional magnification would reveal any more detail.
    
    				Drew
    

  Don't they have filters to protect the equipment?

  Also, are they going to try to get a look at Mercury or is that too
close to the sun and out of safty limits?

  George

>  Don't they have filters to protect the equipment?

No, they have filters to do science -- they have a big door to protect the
equipment.

>  Also, are they going to try to get a look at Mercury or is that too
>close to the sun and out of safty limits?

It's highly unlikely that they would risk the telescope to peak at
Mercury.  If they ever did, it would be near the end of its life when
they were very sure of the guidance and other systems (if it is optically
possible to look at it at all without damaging the telescope).

As Drew noted, it's not possible and it's not really the purpose of the
scope.


- dave

    Among other things, they have a big door that clangs shut across the
    "business end" of the HST if all else fails to prevent it from pointing
    at too bright an object.  That happened accidentally at least once near
    the beginning of the mission.  It is quite a mess to get it back into
    observing condition after one of those!
    
    Burns
    

From: [email protected] (Ron Baalke)
Date: 18 Dec 90 19:09:02 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.


                          HST STATUS REPORT
                          December 13, 1990

     Activities during the early part of this period were postponed due to
the safing event involving the failure of rate gyro 6, which occurred on
December 3. One of the two powered-off spare rate gyros (#2) was brought
on line, and the observatory was recovered from safemode over the weekend.
Science assessment activities began again on Monday, December 10.  During the
safemode period, engineers regenerated a health and safety software load,
quality checked it and loaded it into the HST.  Safemode recovery was started
at 01:00 EST on Saturday, December 8.  In addition, recovery of the
Wide Field/Planetary Camera (WF/PC) was initiated.  A high temperature
decontamination effort is used to clean the Charge Coupled Devices (CCDs) of
contaminants which may have collected there when power had been removed. The
procedure calls for the use of heaters for 8 hours and then returning to normal
configuration.  The CCDs cool down sufficiently in 90 minutes to allow
resumption of normal operations.  Also recovered from safemode were the Goddard
High Resolution Spectrograph (GHRS), the High Speed Photometer (HSP), the Faint
Object Spectrograph (FOS), and the Faint Object Camera (FOC).  Other items of
interest:

     SPHERICAL ABERRATION: The final prescription for the WF/PC2 corrective
optics is expected to be sent to the Jet Propulsion Lab in Pasadena,
California, in the next 10 days.  This is a slip of about a week from the
planned December 15 date, but continues to support the WF/PC2 development
schedule.

     SOLAR ARRAYS: The revised software for the Solar Array Gain Augmentation
(SAGA) was uplinked on November 27 and activated on several occasions with
encouraging results.  Further testing was deferred as work centered on recovery
from the safemode.  Further tests are planned for early January or early
February.

     SECONDARY MIRROR: On Sunday, December 16, activities will begin to remove
1.75 arc minutes of the 3.5 arc minutes total tilt in the position of the
secondary mirror.  This tilt was introduced earlier in the mission when
erroneous conclusions regarding secondary mirror tilt were derived Wave Front
Sensor #1 and 3 calibration data files.  Problems with the logic of those
conclusions versus prelaunch and observed orbital data led to a review of the
involved ground support software.  Later, engineers determined that Wave Front
Sensors 1 and 3 were reversed in the ground analytical software logic.

     Analysis of the effects of the current tilt on optical system performance
indicated that significant improvement in performance would result from
reduction in or elimination of the existing 3.5 arc minutes.  This conclusion
was confirmed during an orbital mirror tilt test two weeks ago, during which
1.75 arc minutes of the tilt were temporarily removed.  Work to finalize the
ultimate "best focus" secondary mirror position will continue into January.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

                      HST Status Report

                      December 14-19, 1990



     Wide Field/Planetary Camera (WF/PC) observations of Mars,
designed to provide global monitoring of the planet during selected
seasons of the year, were conducted successfully.  HST's Mars
observations,  being carried out by a General Observer (GO), will
extend over at least three years and will provide information on
the daily development of the planet's cloud complex.  During the
appropriate season, dust storm development will be imaged
frequently to measure storm dynamics.  In addition, ozone
concentrations related to water abundance will be studied.


	On Sunday (December 16), the secondary mirror tilt was changed
from 3.5 arc minutes off plane to 1.75 arc minutes.  The effect of
this change will be analyzed over the next few weeks.  Following
the analysis, a "final" tilt position for "best focus" will be
uplinked to the observatory.


	A 12-member review committee investigating the failure of one
of the HST rate gyros met for the first time on Wednesday (December
19).  The review team is comprised of senior technologists with
discipline strengths in systems, controls, gyro technology, circuit
design, electrical components, and the effects of radiation on
electrical components.  Chairman is Dr. H. Richard Freeman, Chief
Engineer in Goddard's Flight Projects Directorate.  Other members
of the committee include William F. Tallant; Guillermo E.
Rodriguez; Mitchell L. Davis; Michael D. Femiano; Henry C. Hoffman;
Walter Squillari; and John J. Yagelowich, all of Goddard.  Others
are John W. Kelly, of McDonnell Douglas; John W. Adolphsen, of Vail
Research and Technology; and P. Bene and F. Reschke, of Lockheed
Missiles and Space Co.  


Other items of interest:

	The Independent Optical Review Committee (IORC) has defined
the "final" prescription for the WF/PC2 corrective optics.  The
prescription will be presented by JPL to the optics maker to
produce the WF/PC2 corrective mirrors.

                             ######  

From: [email protected] (Ron Baalke)
Date: 16 Jan 91 22:29:25 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.

HUBBLE SPACE TELESCOPE STUDIES MASSIVE STAR IN NEIGHBORING GALAXY
 
     Astronomers working with the Goddard High Resolution
Spectrograph, an advanced instrument on NASA's Hubble Space
Telescope (HST), reported today on what they call the best
spectrograms ever obtained of Melnick 42, a very massive star in a
galaxy 170,000 light-years from Earth.  The report was presented to
the meeting of the American Astronomical Society in Philadelphia by
a team led by Dr. Sally Heap of NASA's Goddard Space Flight Center,
Greenbelt, Md.
 
     Dr. Heap said that preliminary analysis of the spectrograms
shows that Melnick 42 is between 80 and 100 times more massive than
the sun, making it one of the most massive known stars.  Further,
the analysis reveals that Melnick 42 is shedding its hot gases at a
furious rate in a so-called "stellar wind" that strips the star of
an amount of gas equal in mass to the sun every 100,000 years.
 
     She explained that Melnick 42 is a hot young supergiant star in
the Large Magellanic Cloud (LMC), a galaxy neighboring the Milky
Way.  The star may be only 2 million years old, compared with the
4.6-billion-year age of the Earth.  Melnick 42 has a surface
temperature of about 86,000 degrees Fahrenheit, or eight times
hotter than the sun.  According to present theory, Melnick 42 will
explode as a supernova within the next few million years, while the
sun will continue to shine for several billion years.  Dr. Heap
added that Melnick 42 is more than a million times brighter than the
sun.
 
     She said her observations were made possible because Hubble's
orbit is above the Earth's atmosphere which blocks the far
ultraviolet light from reaching ground observatories.  Also crucial
to making the observations was the spectrograph's tiny entrance
hole, only about 3/75th of an inch on a side, into which HST
focussed the bright core of the star's image.  "This excluded
interfering light from stars near Melnick 42, which usually hampers
observations," Dr. Heap explained.
 
     The purpose of the research, which involves astronomers in the
United States and Europe, is to study how the chemical makeup of hot
stars (stars hotter than the sun) influences the way in which the
stars change with time on their inexorable road to stellar
explosion.  Some astronomers had thought that the low abundance of
elements heavier than helium in stars of the LMC (such as Melnick
42) compared to stars in the Milky Way galaxy would result in the
LMC stars having rather weak stellar winds.  "Our findings on
Melnick 42, if confirmed by additional study, seem to contradict
this assumption," Dr. Heap said.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Date: 16 Jan 91 21:28:32 GMT

	Data from the Hubble Space Telescope has allowed astronomers to
improve the accuracy of the yardstick used to measure interstellar
distances, a first step in improving knowledge about the size of the
universe, an official said Wednesday.
	Several months ago, the $1.5 billion telescope was used to photograph
supernova 1987A, an exploding star in the Large Magellanic Cloud, a
companion galaxy to Earth's Milky Way.
	The spectacular photograph showed an expanding shell of debris around
the destroyed star, a feature that allowed space telescope researchers
to refine their knowledge of the distance to the nearby galaxy.
	Prior to Hubble's launch, the supernova was believed to be between
143,000 and 179,000 light years from Earth -- an uncertainty of about 30
percent. A light year is the distance light, traveling 186,000 miles per
second, covers in one year.
	Based on the Hubble data, the supernova is now believed to be about
169,000 light years away with an uncertainty of just 5 percent.
	``We've used the picture of supernova 1987A to infer much more
accurately ... what the distance between ourselves and the Large
Magellanic Cloud is,'' said Hubble science director Albert Boggess.
	By measuring the apparent size of the ring, and using other data to
determine the speed of the cloud's expansion, researchers were able to
compute its actual size and thus the distance to the supernova.
	``This is the first step in what we've always said is one of the
important objectives of HST, and that is, to improve our understanding
of the size of the universe,'' Boggess said by telephone from
Philadelphia, where the American Astronomical Society is holding its
annual meeting.
	``The first stepping stone is to go from here to the Magellanic
cloud. That will allow us to calibrate other objects we find in the
Magellanic clouds and to use those at further distances.''
	Because of the vast distances involved, astronomers can directly
measure the distances to only a small number of relatively nearby stars
in the Milky Way. To measure the distances to galaxies, astronomers rely
on a variety of other, more indirect methods, including the behavior of
Cepheid variables.
	Cepheid variables are stars that periodically expand and contract by
up to 30 percent, causing them to brighten and dim in a rythmic manner.
	In 1912, Harvard astronomer Henrietta Leavitt discovered that the
time required for a complete ``cycle'' is directly related to the
overall luminosity of the star. The longer the ``period,'' the brighter
the star.
	Armed with this knowlege, astronomers can determine how bright a
Cepheid actually is versus how bright it appears from Earth. And that
allows them to determine the distance to the object.
	The Hubble data on supernova 1987A can be used to calibrate, or
refine, the values used for Cepheids in the Large Magellanic Cloud,
which may allow researchers to refine the distances to Cepheids in more
distant objects.
	Boggess said engineers and scientists are slowly but steadily working
the bugs out of the Hubble Space Telescope, learning how to compensate
for the slight jitter caused by its flexing solar panels and fine-tuning
their ability to precisely aim the instrument at its targets.
	While the telescope's two cameras are relatively easy to aim, it is
far more difficult to get a target's light into the small apertures of
the instrument's spectrographs. At present, Boggess said, spectrographic
observations are successful only about 50 percent of the time.
	But he said engineers were well on the way to resolving the problem
and that Hubble's inability to sharply focus starlight because of its
flawed primary mirror did not have a major impact on such observations,
although longer-than-planned exposures are required.
	``Since the spectrographs do have these very small apertures, they
reject all the bad parts of the image anyway,'' Boggess said. ``So the
data quality is good.''

    Question::
    
    How much of Hubble is working % wise out of it's total operational
    capacity/design.
    
    And will Hubble be definitely repaired and when.
    
    Thanks,
    Simon

    Hubble will get it's "eyeglasses" to correct the spherical aberation in
    1993 during a scheduled (prior to launch) servicing flight. This should 
    bring it to 100% capabilities. It is already doing science that can't be 
    done from the ground (under the atmosphere) and the visible light 
    resolution is said to be as good or better than current ground based 
    telescopes. An example is the two disk image of Pluto and Charon (sp?). 
    This is only resolvable to a smeared disk from the surface telescopes.

In the popular press I've seen estimates of 60% capability.

Besides the spherical aberration problem, the solar array oscillation that
occurs when HST crosses the day/night terminator continues to cause what
is known as "fine lock" problems -- in other words, HST can't always maintain
its lock on a star within specifications.

A few months ago the institution which controls HST's science observations
(STScI) held a series of meetings which discussed how they would recover
from the the most pressing problem with HST: the spherical aberration caused
by the main mirror.   A number of both conservative and wild ideas were
floated around.  I was surprised to see that one of the more radical ideas
has apparently received the endorsement of STScI.

As previous replies have noted, the WF/PC-II camera is currently under
final development at JPL.  Since WF/PC (-I) has been scheduled for replacement
in 1993, corrective optics have been prescribed for the new WF/PC -- this
would leave the other 3 instruments still dealing with the mirror defect
(notably the FOC).

The new proposal currently floating around is to sacrifice one of the
instruments and use its slot for a set of corrective optics that would fix
the remaining instruments.   The HSP (High-Speed Photometer) would be
sacrificed so that the WF/PC, FOC, and GHRS could operated at specification.

A bold fix from the science quarters.  It will be interesting to see if this
option will actually fly.

- dave

                 Hubble Space Telescope Update

                         January 2, 1991



	NASA's Hubble Space Telescope (HST) was deployed from the
Space Shuttle Discovery (STS-31) at 3:38 P.M. EDT on April 25,
1990, sending it on a 15-year mission to search the universe for
new discoveries, other galaxies and the very origins of the
universe itself.  Following deployment of the telescope on
Discovery's 50-foot mechanical arm, deployment of the spacecraft's
solar arrays and the extension of the telescope's dish antennae,
Astronaut Steve Hawley released the Shuttle's grip on Hubble,
setting the telescope into orbit.
 
      HST's Orbital Verification (OV) started with minor problems,
including a delay in activating the telescope's high-gain antennae. 
The one problem the controllers at Goddard Space Flight Center
could not solve was a slight vibration, or "jitter," as HST moved
from sunlight to darkness and darkness to sunlight.

       On May 20, controllers began receiving the first series of
images from HST.  Designed as a simple engineering test, it proved
an added bonus for the scientists, providing bright, crisp images
of a double star in the Carina system.  The images were much
clearer than pictures of the same target from ground-based
telescopes.  However, the telescope's mirrors still had to be fine-
tuned.  As controllers began moving the mirrors to focus the images
more clearly, a "spherical aberration" in the primary mirror--later
determined to be a manufacturing flaw--only 1/50th the width of a
human hair, was discovered, which prevents the telescope from
focusing all light to a single point.
 
      At first, some scientists believed the defect would cripple
the telescope badly, but later activities have shown that not to
be true. Most affected by the spherical aberration are the Wide
Field/Planetary Camera (WF/PC) and the European Space Agency's
Faint Object Camera (FOC). The telescope's ability for
spectroscopy--the observation and study of starlight--will suffer
only minimal impact because these instruments--the Goddard High
Resolution Spectrograph (GHRS) and the Faint Object Spectrograph
(FOS)--do not require finely focused light to perform their
observations.  The High Speed Photometer (HSP), which measures the
intensity and wavelength of light from a particular region in
space, is still being evaluated.  The telescope's Fine Guidance
Sensors (FGSs) currently are being calibrated. Two of the sensors
lock onto target stars and maintain the HST's pointing  stability. 
A third sensor is used for astrometry, the precise measurement of
the distance between target stars and other stars.


	A number of photo releases have been made:

     First light (WF/PC), May 20
     Enhancement of first image, May 22
     NGC 188 (ESA FOC), June 22
	30 Doradus Nebula, August 13
	1987A Supernova, August 29
	NGC 7457 Galaxy, August 29
	Gravitational Lens G2237, September 12
	Young Star Cluster R136, September 12
	Supernova 1987A, September 12
	Saturn, October 4
	Galaxy NGC 1068, October 4
	Pluto, October 4
	Radio Galaxy PKS 0521-36, October 4
	R Aquarii, October 4
  	Star Cluster M-14, October 4
	Comet Levy, October 10
	Orion Nebula Jet Structure, November 6
	Orion Nebula Window-Curtain, November 6
	Storm on Saturn, November 20

	Even with its impaired vision, the value of HST was
underscored when the Wide Field/Planetary Camera photographed the
R-136 star cluster in the star cloud known as 30 Doradus.  As
recently at 1980, astronomers believed that R-136 was a single
star.  New techniques in the 1980s gave observers a view of eight
distinct objects where they had thought only one existed.  Recent
ground-based images suggested there might be as many as 27 stars
in the cluster.  When the scientists saw Hubble's image, they
counted more than 60 stars. The cluster is located within the Large
Magellanic Cloud, a neighboring galaxy, and is about 160,000 light
years from Earth.  A light year is the distance light travels in
a year's time through a vacuum, roughly six trillion miles.  

	The photo of R-136 proved that with computer enhancement, the
WF/PC has significant capability.  Computer enhancement eliminates
some of the blurred light around the center of a star image,
effectively sharpening the focus.  Computer improvement would have
been used even on the sharpest of photographs provided by perfect
mirrors, but the technique has proved a more useful tool to reduce
the effect of spherical aberration.  Despite the telescope's
problem in obtaining a sharp focus, Hubble's imaging of bright
targets is still better than the best images produced through
ground-based telescopes on a clear night.  

	The HST image of Supernova 1987A was taken by the European
Space Agency's Faint Object Camera.  It marked the first time that
the exploding outer envelope of 1987A had been photographed
directly.  It also resolved, in unprecedented detail, a mysterious
elliptical ring around the remnants of 1987A. 

     The ring, 160,000 light years from Earth, is destined to be
relatively short-lived with expanding debris from the supernova
overtaking and disintegrating it within a century.  

	The Faint Object Camera also captured a detailed image of the
gravitational lens G2237 + 0305--sometimes referred to as the
"Einstein Cross."  Gravitational lensing occurs when the light from
a distant source passes through or close to a massive foreground
object.  As a result, several images of the background object may 
be seen.  In the HST image, light from a quasar, approximately
eight billion light years away, passes through a galaxy 400 million
light years away, or about 20 times closer.  The light from the
quasar is bent by the gravitational field of the galaxy, producing
four bright images.

	On August 26, the Wide Field/Planetary Camera photographed
Saturn at a distance of 1.39 billion kilometers (860 million miles)
from Earth.  The HST image revealed unprecedented detail in
atmospheric features at the planet's north pole, a region not
extensively imaged by the Voyager space probes.

	HST's WF/PC image of the core of galaxy NGC 1068 revealed 
far more detail than ever has been seen previously from the ground.

	ESA's Faint Object Camera looked into the inner core of the
so-called "symbiotic star," R. Aquarii.  The image revealed new
details of the star.  R. Aquarii is one of the closest stars known
to undergo violent eruptions that spew out huge quantities of
nuclear material into surrounding space.  

	On September 27, the HST's WF/PC observed the icy nucleus of
Comet Levy, revealing detail much more clearly than could be done
by ground-based telescopes.  The comet was at a distance of 160
million kilometers (100 million miles) from Earth.

	HST took the clearest pictures ever of our solar system's most
distant object, the planet Pluto.  Using ESA's Faint Object Camera,
the image was made of Pluto and its moon, Charon, and was the first
long duration HST exposure ever taken of a moving target.

	The Orion Nebula was photographed by the WF/PC.  The image
revealed the detailed structure of a newly-discovered jet of
material streaming away from a young star in the nebula as well as
a thin sheet of gas, known as a "window curtain," at the edge of
the famous nebula, an estimated 1,500 light years from Earth.  

	Late in September, astronomers discovered a new "white spot"
near the equator of Saturn.  Over the next few days, they noticed
the cloud was growing and spreading along the equator and climbing
higher in the atmosphere.  In November, HST's WF/PC observed this
rare and unusual event. 

      With the images, scientists were able to study the vertical
growth of the clouds (believed to be mainly ammonia ice crystals)
and to determine the existence of a very turbulent atmosphere, very
similar to the cloud system that trails the Great Red Spot on
Jupiter.  
                                
	Hubble completed its Orbital Verification activities,
officially transitioning to Science Verification on November 12.
During the initial phase of a two-phase Orbital Verification
period, managed by the Marshall Space Flight Center, Huntsville,
AL, the emphasis was on checking out and calibrating the
spacecraft.  The second phase was managed by Goddard Space Flight
Center, Greenbelt, MD. In Science Verification, the concentration
is on calibrating the scientific instruments onboard the
spacecraft.  Science Verification, also managed by the Goddard
Space Flight Center, is expected to be completed by December 1991. 
After that, the responsibility for science operations is assigned
to the Space Telescope Science Institute at Johns Hopkins
University, Baltimore, MD.

	The instruments on the HST are modular, designed for quick and
simple replacement, much like changing tapes in a video cassette
recorder.  Because replacing Hubble's mirror in space is out of the
question and bringing the telescope back to Earth for repair is not
practical (reentry through Earth's atmosphere would subject the
telescope's sensitive optics to contamination) scientists plan to
compensate for the spherical aberration by modifying the
telescope's replacement instruments, or "second generation"
equipment.  The first instrument scheduled for replacement is the
WF/PC.  Once a precise prescription to correct the spherical
aberration is determined, small corrective mirrors or lenses that
are expected to restore the telescope's originally planned imaging
capabilities will be installed in the "second generation" WF/PC,
or WF/PC2.  The new camera is expected to be installed on a HST
Space Shuttle repair mission in 1993.  That mission also is
expected to carry out repair or replacement of the bothersome solar
arrays and to replace a gyro that failed in early December.

       There also is a possibility that a robot module known as
COSTAR (Corrective Optics Space Telescope Axial Replacement) might
be installed in HST on the 1993 repair mission.  COSTAR has
completed a feasibility study and now is undergoing a definition
study to determine if it would correct the spherical aberration and
if it could be built in time for the 1993 mission.  Once inserted
by the astronauts, the device would project a robotic arm about one
foot toward two light-gathering mirrors and into a beam of light
that passes through a hole in the center of the primary mirror
after having bounced off the secondary mirror.  Retractable
brackets on the side of the arm would position tiny corrective
mirrors over the "eyepieces" to the other axial instruments and
reflect "corrected" light into them. Astronauts would remove the
High Speed Photometer on HST to make room for COSTAR.

	As operations moved into December, the spacecraft experienced
a safing event involving the failure of rate gyro #6.  The event
occurred on December 3. The on-board computers sensed something was
wrong, causing the flight software to drop the No. 6 gyro from the
pointing control loop and put the spacecraft into a three-gyro
configuration.  The spacecraft has six gyros, but only uses four
for normal operations.  Preliminary analysis indicates that there
probably was a failure in the circuitry in the No. 6 gyro
electronics control unit or in the wiring between the gyro and the
control unit.  The No. 2 gyro was activated later in the week, and
Science Verification activities were resumed on Sunday, December
9.  

                             #######

                      HST Status Report #9

                       December 6-13, 1990


	Activities during the early part of this period were postponed
due to the safing event involving the failure of rate gyro 6, which
occurred on December 3.  One of the two powered-off spare rate
gyros--No. 2--was brought on line, and the observatory was
recovered from safemode over the weekend.  Science assessment
activities began again on Monday, December 10.
	During the safemode period, engineers regenerated a health and
safety software load, quality checked it and loaded it into the
HST. Safemode recovery was started at 1 a.m. EST on Saturday,
December 8.  In addition, recovery of the Wide Field/Planetary
Camera (WF/PC) was initiated.  A high temperature decontamination
effort is used to clean the Charge Coupled Devices (CCDs) of
contaminants which may have collected there when power had been
removed.  The procedure calls for the use of heaters for eight
hours and then returning to normal configuration.  The CCDs cool
down sufficiently in 90 minutes to allow resumption of normal
operations.  Also recovered from safemode were the Goddard High
Resolution Spectrograph (GHRS), the High Speed Photometer (HSP),
the Faint Object Spectrograph (FOS), and the Faint Object Camera
(FOC).  

Other items of interest:

	Spherical Aberration--The final prescription for the WF/PC2
corrective optics is expected to be sent to the Jet Propulsion Lab
in Pasadena, CA, in the next 10 days.  This is a slip of about a
week from the planned December 15 date, but continues to support
the WF/PC2 development schedule.  

	Solar Arrays--The revised software for the Solar Array Gain
Augmentation (SAGA) was uplinked on November 27 and activated on
several occasions with encouraging results.  Based on analysis of
the data from this period, a new set of limiter values will be
selected and uplinked in January for evaluation.

	Secondary Mirror--On Sunday, December 16, activities will
begin to remove 1.75 arc minutes of the 3.5 arc minutes total tilt
in the position of the secondary mirror.  This tilt was introduced
earlier in the mission when erroneous conclusions regarding
secondary mirror tilt were derived from Wave Front Sensor #1 and
#3 calibration data files.  Problems with the logic of those
conclusions versus prelaunch and observed orbital data led to a
review of the involved ground support software.  Later, engineers
determined that Wave Front Sensors 1 and 3 files were reversed in
the ground analytical software logic.


	Analysis of the effects of the current tilt on optical system
performance indicated that significant improvement in performance
would result from reduction in the existing 3.5 arc minutes.  This
conclusion was confirmed during an orbital mirror tilt test two
weeks ago, during which 1.75 arc minutes of the tilt were
temporarily removed.  Work to finalize the ultimate "best focus"
secondary mirror position will continue into the new year.  


                            ######NASA Facts



                     HUBBLE SPACE TELESCOPE:
                     COMMAND/CONTROL,
                     OBSERVATION AND DATA FLOW

	The deployment of the Hubble Space Telescope (HST) into its
operational orbit by the Space Shuttle on April 25, 1990 set the
stage for a flow of scientific data from the HST's six instruments.
	The principal components of the command/control, observation
and data flow cycle are:  the HST itself; on-orbit Tracking and
Data Relay Satellite System (TDRSS); the TDRSS ground terminal at
White Sands, New Mexico; a domestic communications satellite
(DOMSAT); the Space Telescope Operations Control Center (STOCC),
and the Space Telescope Data Capture Facility (STDCF), both at
Goddard Space Flight Center, Greenbelt, Maryland; and the Space
Telescope Science Institute, located on the Homewood Campus, Johns
Hopkins University, Baltimore, Maryland.  
	The following are the steps in the cycle:

            Space Telescope Science Institute (STScI)

	The cycle is touched off from the STScI where--in response to
requests from the worldwide science community-- staff scientists
determine the astronomical targets (objects or phenomena) for the
HST to observe.  
	First users of the HST are those scientists who have helped
in the development of the telescope and its instruments. 
Additionally, in recognition of their contribution to the program, 
observing time will go to scientists from nations which are members
of the European Space Agency (ESA).
	Target requests--together with the specific observing
procedures needed for each target--are sent from the Institute to
the Space Telescope Operations Control Center (STOCC) at Goddard.

            Space Telescope Operations Control Center

	The STOCC is located in Building Three at Goddard.  The target
requests and observing procedures from the Institute come into the
STOCC's Science Support Center (SSC).  Here, operations staff
convert the target requests into an actual observing schedule for
the HST.
	SSC personnel then pass the schedule to the Payload Operations
Control Center (POCC), also in the STOCC.
	In the POCC, the observing schedule for each of the HST's
instruments is integrated into a master timetable.  This timetable
includes availability of the TDRSS for receiving target commands
from the STOCC and, in turn, relaying data from the HST back to
Earth.
	Command loads, which direct the movements of the HST for
coverage of its targets, are issued from the POCC to the White
Sands Ground Terminal (WSGT) through the orbiting DOMSAT.
                              - 2 -


	At the same time, POCC personnel monitor the HST 24 hours a
day.  This monitoring includes the HST's electrical power system,
attitude control, thermal environment and communications system.

           White Sands Ground Terminal (WSGT) and the 
        Tracking and Data Relay Satellite System (TDRSS)

	The WSGT, as instructed by the POCC at Goddard, will transmit
the command loads for relay through the TDRSS--currently three
geosynchronous satellites deployed into a fixed orbit 35,680
kilometers (22,300 statute miles) over the Equator at 41 degrees,
171 degrees and 174 degrees west longitude.
	The Tracking and Data Relay Satellites, each with two 4.9
meter (16-foot) diameter mesh antennas which operate in S-band and
K-band frequencies, can easily accommodate the HST data rate of
approximately one million bits per second.

                  Data Flow:  HST To The Users

	The real-time telemetry (or data from the spacecraft recorder)
is sent from the HST via the orbiting TDRS to the WSGT and then
through the DOMSAT to Goddard's STOCC and Space Telescope Data
Capture Facility.
	At the STOCC, the data is monitored by SSC personnel and
simultaneously is forwarded via land lines to astronomers at STScI
for quick-look analysis.  Following processing by STDCF, formatted
and quality-checked data are transmitted to the STScI within 24
hours of receipt.  
	At the STScI, instrument calibrations are applied to make the
data products (magnetic tapes, photographs, plots) suitable for
scientific analysis.  The calibrated data products are then
provided to the user scientists and also deposited in data
archives.
	These archives will be maintain at the STScI and at the
European Coordinating Facility in Munich, Germany, for the benefit
of other scientists who will be able to re-use the data for
additional research projects in the future.

                                ###### 

The Space Telescope Science Institute is publishing a quarterly newletter called
"The Observer".

If you want to get an idea of the content (sans pictures), take a look at

   Pragma::Public:[NASA]Observer_1.PS

This is my best shot at formatting this document so far (once I get my copy
I'll have a better idea of what it should look like).

6 pages (and a lot of whitespace).


- dave

From: [email protected] (Robert David Bunge)
Newsgroups: sci.astro
Subject: Some HST results and news
Date: 25 Feb 91 14:40:50 GMT
Organization: University of Maryland at College Park


                       Some early results from HST
 
 
(I wrote up the following after attending a Symposium and a Plenary Lecture
at the American Association for the Advancement of Science (AAAS) in
Washington, D.C. early last week.  In addition, some information was gleamed
from interviews afterwards.  I hope the more experienced science readers
of sci.astro/space will excuse the sometimes simple language - aimed at new
readers who may have not been around during previous discussions - Bob
Bunge)
 
----------------------
 
Hubble Space Telescope principle investigators presented a mixed review of
early science results from HST ranging from photographs showing detail
never imaged before, amazing new detailed spectra to two crippled
instruments, one perhaps even fatally.
 
In addition, investigators also showed as much concern over the
spacecraft's "jitter" as they did the flawed mirror.
 
Riccardo Giacconi, Director of the Space Telescope Science Institute
(STSI), said for the most part the space telescope is performing well
considering the mirror problem, but hinted that a jitter introduced by
shaking solar panels is more of a problem than previously thought.  The
jitter results when the solar panels expand and contract as they move in
and out of the shadow of the Earth.
 
While the flawed mirror has affected almost all science programs, in many
cases it can be corrected for during either the planning stages or during
data reduction.
 
"Even with ST in crippled condition, we can still do science, but ST can't see
galaxy formation.  Nature has been very kind to us even through we have a
crippled telescope," Giacconi said.  Seeing the early period of galaxy
formation had been a key area of research that HST promised to probe.
 
However, attempts at correcting the jitter by adjusting the telescope's
reaction wheels has not been completely successful.  This has affected the
telescope's ability to place starlight into the High Speed Photometers
(HSP) tiny apertures along with planned astrometry to be done with the Fine
Guidance Sensors.  
 
Giacconi also commented the war in the gulf has affected them somewhat
because of heavy Department of Defense usage of communication satellites
(TDRSS).  Apparently this at times this as slowed down the amount of data
received.
 
Eric Chaisson of STSI outlined plans to correct the jitter and the flawed
optics.  He explained aside from corrective optics in the new Wide Field
Planetary Camera (WF/PC, pronounced "wiff-pick") the Corrective Optics
Space Telescope Axial Replacement (COSTAR) would replace the HSP and swing
corrective optics using mirrors over the apertures of the remaining
instruments.  He said they are expecting to receive the go ahead on COSTAR
in the form of a recommendation from a group of astronomers in late
February.
 
Chaisson said the jitter was pronounced at two frequencies, 1/6th and 1/10
Hz, and while software has pretty much corrected the 1/6 Hz jitter, the
1/10 Hz jitter was too fast for the reaction wheels to correct and would
most likely remain a problem until the telescope's solar panels are
replaced.
 
He also added they have a shuttle flight scheduled for late (penciled in for
November) 1993 to try three repairs.  The first is to replace the current
WF/PC with WF/PC II.  The new camera will have newer filters and CCD
detectors.  The second goal will be to install new solar panels that will
eliminate the cause of the jitter.  The third would be to install COSTAR.  To
do all three of these tasks will require three complete days of astronaut
EVA, more than ever done during any previous shuttle flight.  
 
"We have addressed these concerns to the shuttle people and they tell us
it is possible, so we are planning to do it," he said.  It was not said if they
will also try to replace a broken gyro during this flight.  However, the news
of COSTAR and its corrective optics hasn't been good news for everyone.
 
In a pessimistic press release handed out before the symposia, HSP
principal investigator Robert C. Bless of the University of Wisconsin-
Madison, reported they were "dead in the water" because of the telescopes
inability to place the center section of a stellar image on any of a number
of tiny apertures in HSP.  This bad news has been aggravated by the news
that the HSP will be replaced by COSTAR just as the jitter problem is fixed.
 
But Bless's co-researcher Jeffery Percival was more upbeat about the
status of HSP.  Even though he didn't have any science results to present,
he said a recent software fix for the jitter showed some promise and they
have been promised priority scheduling before the 1993 repair flight if HSP
regains some usefulness.
 
Chaisson added that the HSP was the most under subscribed instrument and
was scheduled for early replacement even before the affects of the jitter
on HSP became known.
 
F. Duccio Macchetto of the European Space Agency reported on early
results obtained with the Faint Object Camera (FOC).  He showed slides of
Pluto and Charon, the "Einstein Cross" gravitational lens and the ring
around supernova 1987a.  He reported that the FOC is operating flawlessly
and researchers have been happy with results in light of the flawed optics.
 
Researchers from both the Goddard High Resolution Spectrograph (GHRS) and
the Faint Object Spectrograph (FOS) reported good results even with the
optics and presented baseline observations designed to allow the
scientific community to gauge the affect of the flawed optics on any future
science programs.
 
John Brandt of the University of Colorado at Boulder reported on spectra
of red giant Alpha Tauri, blue supergiant Melnick 42 and Xi Persei.  He said
while the Large Science Aperture in GHRS had suffered a loss of about 50
percent of expected resolution, the Small Science Aperture was mostly
unaffected.  In both cases, the spread out stellar images mean longer
exposures are required and targets must not be close to other objects. 
With each object he displayed GHRS spectra against ground based spectra
to show that ST was resolving many new - 24 in the case of Alpha Tauri
across a 50 angstrom band, - lines.
 
Richard Harms of Applied Research Corp. in Landover MD reported similar
results with the FOS.  He said the instrument required exposures three to
four times longer because of the flawed optics.  While early results based
on spectra on Seyfert galaxy NGC 1068 and globular cluster M-14 have been
promising, the smallest apertures of the instrument have been rendered
useless by the jitter because the light from an object cannot be centered
on the apertures for any length of time.
 
Laurence W. Fredrick of the University of Virginia reported on science
programs using the Fine Guidance Sensors (FGS).  He said for the most part
astrometry programs are on "hold" because of the jitter and the telescopes
current state of collimation.
 
Apparently, the spherical aberration has affected the (wave front) sensors
that provide information needed to collimate the telescope's optics.  In
turn, this has affected the FGS because they are sensitive to asymmetrical
aberration such as coma and astigmatism introduced because of the bad
collimation.  It is hoped that future movements of the secondary mirror can
be made to correct these problems.
 
Fredrick did show results of some science done with the FGS in the form of
more accurate measurements of the double star ADS 11300.  Researchers
were able to remove error introduced by the jitter to come up with the
most accurate information on this star system yet.
 
James Westphal of Caltech and the principal investigator for the Wide Field
Planetary Camera showed a series of images of Saturn, before and after
the white spot, M-42, NGC 7457 and a pre-release blue light image of Eta
Carina.  The image of Eta Carina clearly showed huge, complex loops of
matter blown off the star.  He said a color image of the star will be
released in the near future.  
 
Westphal also said a team who took images of Mars with the planetary
camera when it was near opposition will also release color images in coming
weeks.  Another up coming WF/PC release will be a new "movie" using some of
the 600 images taken of Saturn while observing the white spot last
November.
 
Westphal said they expect to start taking images of Jupiter within the next
three weeks and they will also target Saturn starting on the 15th of March
if ground based observers report interesting activities following the
ringed planets coming out from behind the Sun.  
 
Later, when asked why it took more than a month to get ST pointed at Saturn
after the discovery of the white spot, Westphal said they had approached
ST's first target of opportunity with caution and some procedures had to
be worked out.  He said currently ST can be pointed to any object within two
days of a decision being made to do so.  
Qf~? 
He also said if the optics had been flawless, the jitter would have affected
the telescope almost as much as the bad optics.  He said some people in the
control room during the night of "first light" had suspected the spherical
aberration long before it was officially announced. 
 
Finally, Robert O'Dell of Rice University reported on what might be the
first case of results from ground based follow-up research based on HST
science.
 
Using an image of M-42 taken with the WF/PC, (see page 32 of the February
_ASTRONOMY_ magazine) spectra taken with a ground based telescope had
shown what was believed to have been a jet of gas shooting from a young
hot star (middle far right side of image just above the horizonal line in the
ASTRONOMY image) is really a ionization front near the star.  But, a
"elephant trunk" shaped bright region nearby (upper far right in ASTRONOMY
image) is a jet from a star.  O'Dell said these objects are described wrong
in an up coming issue of ApJ letters.
 
 
Bob Bunge
[email protected]

From: [email protected]
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military
Subject: Space telescope begins Mars observations
Date: 17 Mar 91 23:06:37 GMT
  
	BALTIMORE (UPI) -- The Hubble Space Telescope is snapping the
sharpest pictures of Mars ever taken from the vicinity of Earth in a
long-term program to monitor seasonal changes in the atmosphere of the
Red Planet. 

	The work eventually may allow scientists to understand global
weather patterns, a prerequisite for any future manned missions to
Mars, according to the Space Telescope Science Institute, which
coordinates Hubble science activities. 

	Preliminary observations with the $1.5 billion telescope
clearly show features of the Martian atmosphere and surface details as
small as 31 miles across. The smallest features detectable by
ground-based instruments are some 93 miles wide. 

	One of the first pictures of Mars released by the Space
Telescope Science Institute was taken during mid-summer in Mars'
southern hemisphere. The picture shows a clear sky over much of the
planet, but a thick canopy of clouds obscuring the frigid north pole
region. 

	``As on Earth, the periphery of this polar hood region is the
locale of intense storm systems which migrate through northern mid
latitudes,'' the science institute said in a news release. ``Details
of the cloud structures can be seen in the HST images.'' 

	Other details visible in the Dec. 13, 1990, image include
Isidis Planitia, a 620-mile-wide impact basin, the heavily cratered
Arabia Planitia region, the windswept Syrtis Major area and the bright
Hellas Planitia basin, which measures 1,118 miles across and 5 miles deep. 

	While Mars has been studied in detail by a variety of space
probes, including the Viking landers, the planet has an active
atmosphere and goes through seasonal changes much like Earth. 

	``To understand Mars' complex meteorology and climate, the
planet must be continually monitored over many of its annual cycles,
much as the monitoring of Earth by terrestrial weather satellites has
improved our ability to understand and forecast weather on our
planet,'' the Space Telescope Science Institute said. 

	Studies with the Hubble Space Telescope will allow scientists
to monitor the surface and atmosphere of Mars to reveal the global
distribution of water and dust clouds at various locations and times
of year. 

	Such research is impossible using current ground-based telescopes 
because of the blurring effects of Earth's turbulent atmosphere. 

	In fact, the sharpest images possible, when Mars and Earth are
closest together every 780 days or so, cannot show surface features
smaller than about 93 miles across. Most of the time, the resolution
is between about 370 and 620 miles. 

	But even when Mars is at its greatest distance from Earth, the
performance of the Hubble Space Telescope's planetary camera is
comparable to that of ground-based instruments when the planets are
closest together. 

	``This makes HST an ideal instrument for monitoring long-term
changes on Mars throughout the planet's 1.8-year orbital period,'' the
science institute said in its release. 

	In addition to taking sharp pictures of the Red Planet,
Hubble's position in space allows the instrument to detect ultraviolet
light from Mars that otherwise would be blocked by Earth's atmosphere.
Such data should allow scientists to monitor water and ozone levels in
Mars' atmosphere. 

	``Comparison of images obtained at different times will reveal
surface, weather and climate changes on the Red Planet and will hasten
the day when scientists can understand and characterize weather and
surface conditions on the planet in preparation for future manned and
unmanned exploration,'' the science institute said. 

	The Hubble Space Telescope was launched from the shuttle
Discovery on April 25, 1990.  While its flawed 94.5-inch mirror
produces blurred images, computer enhancement can nonetheless yield
spectacular results. 

	NASA plans to correct the blurring program in 1993 when a
shuttle crew is scheduled to install a new planetary camera equipped
with modified lenses to counteract the mirror's spherical aberration. 

 _(_a_d_v_ _6_:_3_0_ _p_._m_._ _e_s_t_)

From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.tw.science
Subject: Citing Hubble Space Telescope, panel endorses smaller telescopes
Date: 19 Mar 91 19:22:16 GMT 
 
	WASHINGTON (UPI) -- Citing the time and money spent on the
Hubble Space Telescope, a report Tuesday called for developing more
modest instruments to study the Universe in the 1990s and only a few
large observatories. 

	A 15-member committee organized by the National Academy of
Sciences's National Research Council made the recommendation in the
report, ``The Decade of Discovery in Astronomy and Astrophysics,''
after two years of study. 

	Astronomers hope to use telescopes in space, on planes and on
the ground to answer such questions as how stars form, whether planets
orbit nearby stars, how and when galaxies formed and the ultimate fate
of the Universe. 

	In preparing the report for the National Science Foundation,
NASA, the Smithsonian Institution and other agencies, the committee
considered both the Hubble defect and NASA's ``record of successes in
carrying out other complex missions,'' the report said. 

	``The committee concluded that large telescopes are required
to answer some of the most fundamental questions in astronomy.
However, smaller telescopes can be built and launched more quickly to
answer specific questions, to respond to technological innovations and
to train future generations of scientists,'' the report said. 

	At a news briefing where the study was released, astronomer
Carl Sagan endorsed the report, calling it ``striking'' because it
outlined how astronomy could answer some of the most important
questions about the Cosmos by the year 2000. 

	``It is truly astonishing what astronomy is in the throes of
and is capable of doing,'' Sagan said. 

	John Bahcall of the Institute of Advanced Study in Princeton,
N.J., who led the committee, said that although he and other
astronomers were ``traumatized'' by the Hubble's flaw, the endorsement
of only a few large projects stemmed more from how long it took to
build Hubble. 

	``We were all thunderously affected by the imperfection in the
Hubble mirror,'' he said. ``But I think the conclusion we reached we
would have reached without the Hubble failure. I think if Hubble had
been a great success we still would have said it took too long and
delayed other programs and there should be balance between large
projects and smaller projects.'' 

	The $1.5 billion Hubble Space Telescope, which is expected to
revolutionize humanity's understanding of the Universe, was launched
into orbit in April 1990 after decades of planning. Astronomers later
learned its 94.5-inch mirror suffered from an optical defect that
prevents it from sharply focusing starlight. 

	The National Aeronautics and Space Administration hopes to
correct the problem in 1993 by installing new instruments capable of
correcting the instrument's blurred images. 

	Hubble was the first of four space-based ``Great
Observatories'' astronomers hope will help answer fundamental
questions about the Universe.  The next such instrument, the $617
million Gamma Ray Observatory, is scheduled to be launched next month.

	From more than 50 proposals, the report endorsed only four
similarly large programs during the 1990s: 

	--The $1.3 billion Space Infrared Telescope Facility, which
would complete the Great Observatory program, would be almost 1,000
times more sensitive than Earth-based telescopes operating in the infrared. 

	--An $80 million infrared-optimized telescope, equipped with a
giant 26.2-foot mirror, on Mauna Kea in Hawaii, which ``would provide
a unique and powerful instrument for studying the origin, structure
and evolution of planets, stars, and galaxies.'' 

	--The $115 million Millimeter Array, an array of telescopes
that would provide ``high-spatial and high-spectral-resolution images
of star- forming regions and distant star-burst galaxies and ''bring
new classes of objects into clear view for the first time.`` 

	--A $55 million 26.2-foot optical telescope that would operate
from the southern hemisphere and give U.S. astronomers access to
important objects in southern skies because ``all-sky coverage is
essential for pursuing many of the most fundamental astronomical questions.'' 

	The report recommended a series of more modest programs, including:

	--The $230 million Stratospheric Observatory for Far-Infrared
Astronomy, an 8.2-foot telescope that would be mounted on a Boeing 747
aircraft. 

	--The $250 million Astrometric Interferometry Mission, which
would improve by 1,000-fold the precision with which the positions of
celestial bodies are known and perhaps detect the presence of Jupiter-
sized planets around stars up to 500 light years away. 

	--The $15 million Large Earth-based Solar Telescope, which
would ``provide important information about the sun and test the
application'' of so-called adaptive optics. 

	--Spending $30 million on additional 13-foot optical
telescopes ``to provide greater access for U.S. scientists to
state-of-the-art instrumentation capable of addressing significant
astronomical problems.''

	--A $70 million spacecraft dedicated to the Far Ultraviolet
Spectroscopy Explorer satellite, and increasing to five the number of
Explorer satellites, which can be launched on rockets. 

From: [email protected] (Peter E. Yee)
Date: 27 Mar 91 01:38:19 GMT
Organization: NASA Ames Research Center, Moffett Field, CA

Terri Sindelar
Headquarters, Washington, D.C.
(Phone:  202/453-8400)                          March 26, 1991


N91-23

EDITOR'S NOTE:  
HST UPDATE DURING EDUCATOR SATELLITE VIDEO CONFERENCE


	On April 2, Dr. Ed Weiler, Program Scientist for the Hubble Space 
Telescope (HST), will discuss the challenges encountered by the HST 
team as well as discuss and show images of the excellent and unique 
scientific findings.  The April 2 conference, the last in a series of four 
educational video conferences conducted annually by NASA's 
Educational Affairs Division, will be transmitted via a Westar IV satellite, 
channel 19, from 2:30 to 4:00 p.m. EST.

	More than 30,000 educators in 50 states are expected to 
participate in this program.  The 1-1/2 hour, interactive video conferences 
are designed to update teachers on NASA programs, demonstrate 
aerospace activities for classroom use and announce new programs, 
products and activities available to classroom teachers.  

	The satellite video conference series is produced by NASA's 
Aerospace Education Services Project from Oklahoma State University 
Telecommunications Center.

	To register for the series, interested teachers should write to NASA 
Aerospace Education Services Project, Videoconference Site, 300 North 
Cordell, Oklahoma State University, Stillwater, Okla., 74078-0422, or call 
405/744-7015.  Registration is free and ensures that announcements, 
publications and other materials for teacher-participants are received by 
the school.  The 1991-92 series of educational video conferences will be 
announced later this year.

[Via NASA SpaceLink.  Not a lot of new information here, and quite a bit
    missing.  Every little tidbit helps I suppose...  -dg]
    
Hubble Space Telescope Performance Report

NASA Fact Sheet March 25, 1991


Background

	No research mission in NASA history has generated higher
scientific expectations than the Hubble Space Telescope (HST).
And few recent missions have received such widespread public
attention, either before or after launch.

	But that's understandable: HST was designed to be the
most powerful astronomical telescope ever built, far surpassing
the capabilities of ground-based optical telescopes for many
kinds of forefront research.  The key to HST power is operation
in space--above the blurring, obscuring and absorbing effects of
the Earth's atmosphere.

	The April 1990 launch of HST was flawless.  Then, two
months later, came the disappointing news of an optical defect in
the HST primary mirror that blurs the telescope's focus--which
prompted some to label the project a disaster.

	 Now, however, a more balanced picture of current HST
capabilities has emerged, together with a much more hopeful
vision of the telescope's research future.  Outstanding
scientific research is already being carried out with HST.
Moreover, instrument upgrades to be provided by future Space
Shuttle servicing missions will permit most, and perhaps nearly
all, of the original HST scientific objectives to be achieved
over the mission's planned 15-year observing lifetime.

HST Optical Design

	The HST optical design is similar to that of many
ground-based telescopes; a schematic of the HST Optical Telescope
Assembly (OTA) is given in Figure 1.  The curved HST primary
mirror, 2.4 meters (nearly 8 feet) in diameter, collects the
light from the object under study and reflects it toward a much
smaller secondary mirror, which reflects the light back through a
central hole in the primary.  The light comes to a focus at the
focal plane behind the primary mirror, producing an image of the
object that can be recorded or analyzed by the HST scientific
instruments.

	Operation above the Earth's atmosphere brings big gains
in performance.  A telescope in space provides much finer image
detail than the same telescope on the ground and permits the
study of fainter objects.  In addition, a space telescope can
observe radiation that is absorbed by the atmosphere and is
therefore unobservable from the ground.  For example, HST was
designed to detect both ultraviolet and infrared radiation as
well as visible light, with emphasis on ultraviolet and
visible-light observations during the initial phase of the HST
observing program.

Fine Detail

	The ability to distinguish between objects that appear
close together on the sky--or equivalently, to record fine detail
in an image--is known as spatial resolution.  High spatial
resolution is needed, for example, to pick out individual stars
in a densely packed star cluster or to probe the core regions of
remote galaxies for evidence of black holes.

	Atmospheric turbulence, however, blurs the view of all
ground-based optical telescopes.  Even under the best "seeing"
conditions, star images are smeared out.  Images of extended
objects--such as planets, comets, luminous gas clouds and
galaxies beyond our own--suffer a loss in detail and clarity.

	The resolution of a telescope in space, by contrast, is
limited only by the diameter of the primary mirror and the
quality of the optical system.  With its 2.4-meter primary, HST
was designed to yield spatial resolution about 10 times better
than that normally achieved by ground-based optical telescopes.

Faint Objects

	Looking out into space means looking back into time.  The
light from a galaxy a billion light-years away, for example, left
that galaxy a billion years ago; we therefore observe such a
galaxy not at it appears today, but rather as it appeared a
billion years in the past.  The farther out we look, the farther
back into time we see.  Observations of very distant galaxies
thus provide important clues to the early history of the
universe.

	Since the most distant galaxies are very faint, however,
their optical images are very difficult to record from the
ground.  Even at night, the Earth's atmosphere itself glows
faintly with emitted and scattered light.  When a galaxy is
fainter than this so-called "sky background," its image is simply
"lost in the noise," like a whisper at a crowded party.
Recording an image under these conditions requires an extremely
large telescope, or unreasonably long exposure times, or both.

	Faint-object observations from space are free of this
atmospheric effect.  They are limited almost entirely by
unavoidable, random noise within the electronic devices used as
light detectors.  Modern detectors are much less "noisy" than the
atmosphere.  HST was therefore expected to image much fainter
galaxies than could be imaged in practice by any ground-based
optical telescope.

Ultraviolet Radiation

	The light our eyes can see represents just one energy
region of the total spectrum of electromagnetic radiation, which
includes radio waves (at the low-energy end of the spectrum),
infrared radiation, visible light, ultraviolet radiation, X rays
and gamma rays (at the high-energy end).  Only the visible light
and radio waves from astronomical objects can be readily studied
from the ground (although visible light is attenuated and
distorted by atmospheric effects).  Radiation in other spectral
regions is partially or totally blocked by the Earth's
atmosphere.

	Every region of the electromagnetic spectrum carries
important information about objects or physical conditions
elsewhere in the universe.  Analysis of ultraviolet radiation,
for example, helps to reveal the chemical composition of the
interstellar medium--the tenuous clouds of gas and dust within
our galaxy that give birth to new stars.  However, only a small
fraction of the weakest ultraviolet radiation penetrates the
atmosphere. (In the case of ultraviolet radiation from the Sun,
this fraction is just sufficient to cause tanning and burning of
the skin.)

	Since ultraviolet radiation can be collected and focused
just like visible light, HST was designed to study this important
spectral region as well.  But there's a catch.  A mirror will
reflect ultraviolet radiation efficiently only if its surface is
extremely clean, as well as very smooth.  Extraordinary
precautions therefore had to be taken during manufacture of the
HST mirrors to ensure that they were free of contamination.

Launch and Deployment

	Hubble Space Telescope (HST) was launched on April 24,
1990, by Space Shuttle Discovery (see Figure 2).  After reaching
the specified orbital altitude of 330 nautical miles (370 statute
miles), the Shuttle supplied full electrical power to HST,
permitting a series of quick checks to verify that the HST
spacecraft was beginning to operate.

	On the next day, HST's solar panels were unfurled,
internal power switched on and the high-gain communications
antenna deployed.  When ground control confirmed that
communication with HST had been established, the Shuttle's
manipulator arm released the telescope into orbit.

Orbital Verification

	Before HST could become fully operational, a sequence of
orbital verification tests had to be performed.  These tests,
expected to take only a few months, included activation of the
telescope's complex pointing and control systems and careful
alignment of the mirrors in the Optical Telescope Assembly (OTA).
It was anticipated that several additional months would be needed
to fine-tune the performance of HST's scientific instruments.

	The focus test, used to determine the optimum alignment
of the OTA mirrors, was a crucial one.  The OTA was first
commanded to go completely out of focus, then to regain focus,
using starlight imaged by one of the HST cameras.

Discovery of Spherical Aberration

	Several such focus tests were carried out during the
weekend of June 23-24.  The results were totally unexpected.  No
position of the secondary mirror could be found which brought the
starlight to a sharp focus.  The star images remained blurred, as
shown in Figure 3. (The spidery "tendrils" surrounding these
images are artifacts of the secondary-mirror supports and
additional supports within the camera.)

	From the observed pattern of image blurring, it shortly
became clear that HST suffered from spherical aberration, an
optical distortion caused by incorrect mirror curvature.  By June
26, NASA Headquarters had received the disappointing news.  NASA
engineers moved immediately to find out whether the problem was
in the primary mirror or the secondary mirror and to determine
whether anything could be done to correct it.

	Because the engineers knew that a flaw in the secondary
mirror would produce an additional aberration known as coma,
tests were run on July 6 to search for this aberration.  No
evidence of coma was found.  It was then clear that the error lay
in the shape of the primary mirror.

Effects of Spherical Aberration

	The HST optical system should ideally focus the light
from a star into a sharp, almost point-like stellar image.
However, spherical aberration in the HST optics causes the
starlight to spread over a broader area, giving every stellar
image an extensive, fuzzy "halo" of light (see again Figure 3).
Although the HST mirrors are the smoothest and most uniformly
coated astronomical mirrors ever made, the shape (curvature) of
the primary mirror does not match that of the secondary mirror.
This mismatch is the cause of the spherical aberration.

Effect on Sharpness of Focus

	Figure 4 illustrates the effect of spherical aberration
on the focus of a telescope mirror.  Figure 4a shows a correctly
curved mirror: all the reflected light rays from a star converge
to a single focal point.  Figure 4b, by contrast, shows a mirror
with spherical aberration: the light rays converge to a variety
of different focal points--causing the resulting stellar image to
appear fuzzy.

	However, figures 4a and 4b do not tell the complete
story--they depict light as traveling in straight-line rays,
whereas light actually consists of waves.  Because of
interactions among these waves, some fraction of the imaged light
always falls outside the geometric center of the image.  This
effect can be included in accurate, three-dimensional computer
plots of the distribution of imaged light intensity over the
focal plane, as shown in Figure 5.

Effect on HST Images

	Figure 5a illustrates the sharp HST stellar image that
was expected.  About 80% of the starlight is focused within a
small region at the center of the focal plane; the remaining 20%
of the starlight falls outside the central peak.  However, this
slight degree of "fuzziness" is unavoidable.  Because of the wave
nature of light, the stellar image of Figure 5a is the sharpest
that can be achieved in space with a flawless primary mirror in
the 2-meter class (a larger primary would produce an even sharper
image).  Computer processing was planned from the beginning to
sharpen HST images still further.

	Figure 5b, by contrast, illustrates the appearance of an
actual HST stellar image; because of spherical aberration, only
about 15% of the light is now brought to a focus very near the
center.  Most of the light--about 85%--falls elsewhere in the
focal plane, producing a fuzzy "halo" more extensive than that in
Figure 5a.

	As Figure 5 suggests, spherical aberration limits current
HST performance in two ways.

Effect on Spatial Resolution

	First, the aberration reduces the spatial resolution of
the telescope--the ability to record fine detail.  If every star
image looked like that in Figure 5a, HST could distinguish two
stars very close together on the sky.  But because every star
image actually looks like that in Figure 5b, the images tend to
overlap, and resolving power is lost.  Because light is spread
out over a larger region of the focal plane, images of extended
objects similarly suffer a loss in detail and clarity.

	However, the loss of resolving power is less important
for bright objects than for faint ones.  The aberrated star image
of Figure 5b still retains a well-defined central "core." If
light from an object is bright enough, computer processing--which
had been planned in any case--can remove most of the fuzzy
"halos" in the HST images.  The image cores then provide good
discrimination of detail.  For bright, high-contrast objects,
such as nearby star clusters, galactic nuclei, and the major
solar-system planets, HST spatial resolution remains much better
than that of any ground-based optical telescope.

Effect on Observations of Faint Objects

	Second, the aberration reduces the ability of HST to
image faint objects, such as distant galaxies.  By contrast with
the pattern of light distribution expected, light within the
aberrated image is spread out at low intensity over a larger
region of the focal plane.  This means that faint objects are
lost either amid overlapping aberrated star images or in the
noise of the HST light detectors.  As a result, HST capability to
image faint objects is currently more like that of ground-based
telescopes, which are in practice limited by sky-background
noise.

Effect on Spectroscopy

	Spectroscopy is the analysis of radiation into its
spectrum of component colors or wavelengths.  The production of a
spectrum requires that the radiation first be passed through a
very narrow slit.  Since the HST aberration broadens all images,
less light from the image passes through the slit than was
originally anticipated.  However, this effect can be compensated
for by increasing the exposure time.  Excellent spectroscopic
measurements can therefore still be made with HST. Because early
priority was given to imaging, the current HST spectrographs are
only now beginning to demonstrate their potential for ultraviolet
and visible-light analysis.

Effect on Ultraviolet Observations

	Fortunately, the HST mirror surfaces appear to be
extremely clean, and ultraviolet reflectivity is good.  HST
therefore continues to provide unmatched capability for
observations in the ultraviolet spectral region.

Testing of the HST Primary Mirror

	The shaping of a telescope mirror includes many cycles of
grinding and polishing a disk of glass; each cycle refines the
shape left by the previous cycle.  This process is always guided
by sensitive optical tests designed to reveal the difference
between the current shape of the mirror and the shape desired.
When the desired shape is achieved, the glass is coated with a
thin film of highly reflective aluminum.  The shaping, testing,
and coating of the HST mirrors were carried out by a private
optical firm under contract to NASA.

How the HST Primary Mirror Was Tested by the Contractor

	The test used for the HST primary mirror surface was a
full-aperture interferometry or "null" test.  A schematic diagram
of the null-test system (not drawn to scale) is given in Figure
6.  An optical device called a null corrector, consisting of a
lens and two curved mirrors, played a key role.  It had been
specially designed and constructed to make a perfectly shaped HST
mirror look spherical.

	In essence, the test system compared light reflected from
a flat reference mirror with light reflected from the curved HST
primary mirror, as modified by passage through the null
corrector.  Light beams from the two mirrors were brought
together, so that the light waves in the beams could interfere
with each other and form an optical interference pattern.  At
each stage of the grinding and polishing process, this
interference pattern was photographed and analyzed to determine
the departure of the current mirror shape from the shape desired.

	Throughout the process, the null corrector was assumed to
be performing as intended.  Unfortunately, undue reliance was
placed on this test device.

	After final testing--which displayed the correct
interference pattern--the optical technicians and NASA managers
were confident that they had constructed the most accurate
astronomical mirror ever built.  However, the outer edge of the
HST primary had in fact been polished too flat by an amount equal
to 1/50 the width of a human hair--a big error in optical terms.

Cause of the Incorrect Mirror Shape

	In August 1990, NASA formed a special board of
investigation, under the leadership of Jet Propulsion Laboratory
director Dr. Lew Allen, to determine why the HST primary mirror
had been incorrectly shaped and why this error had not been
detected before launch.  The Allen committee issued its report to
NASA (the "Allen Report") in November 1990.

	After a detailed review of the mirror fabrication
process, the Allen committee identified the null corrector as the
cause of the problem.  They found that the spacing rods used to
set up the null corrector had been incorrectly used, producing a
1.3-mm error in the spacing of the null-corrector lens.  Detailed
analysis showed that this lens spacing error is almost exactly
that required to explain the apparent curvature error in the HST
primary mirror.

What Actually Happened

	The executive summary of the Allen Report draws these
conclusions about activities at the contractor site:

	"No verifications of the reflective null corrector's
dimensions were carried out... after the original assembly.
There were, however, clear indications of the problem from
auxiliary optical tests made at the time, the results of which
have been studied by the Board. A special optical unit called an
inverse null corrector was built and used to align the apparatus;
when so used it clearly showed the error in the null corrector.
A second null corrector, made only with lenses, was used...  It,
too, clearly showed the error in the primary mirror.  Both
indicators of error were discounted at the time as being
themselves flawed..."

	Unfortunately, this information was never brought to the
attention of NASA. The report continues:

	"Reliance on a single test method was a process which was
clearly vulnerable to simple error...  During the critical time
period, there was great concern about cost and schedules...

	Questions have also been raised about why a full-scale
test of the completed HST Optical Telescope Assembly was not
conducted before launch.  The Allen Report comments as follows:

	"An end-to-end test of the OTA would have been very
expensive to perform at the level of accuracy specified for the
telescope.  The test would have cost on the order of what the OTA
itself cost. . . the test could have required two additional
mirrors as large as or larger than the OTA primary..."

	Moreover, any such tests would have introduced a serious
risk of mirror contamination.  As stressed earlier, HST
performance in the ultraviolet spectral region depends critically
on the cleanliness of the mirrors, in addition to their
smoothness.  Any contamination would have seriously degraded HST
performance in the ultraviolet spectral region.

Current HST Capabilities

	Because of spherical aberration, some of the forefront
research originally planned for HST will have to be deferred
until later in the decade.  For bright, high-contrast objects,
however, HST spatial resolution still surpasses that of any
ground-based optical telescope, permitting HST to produce images
of such objects with a clarity and detail never seen before.  For
observations of faint extended objects, such as distant galaxies,
HST remains the equal of large ground-based telescopes, although
such observations are not planned for the near term.  And HST
still offers unmatched capability for ultraviolet observations.

	HST currently has five scientific instruments available
for observations at the focal plane, plus three Fine Guidance
Sensors, which can also be used for astronomical observations.  A
brief description of these instruments follows.

	The Wide Field/Planetary Camera I (WF/PC I) is designed
for high-resolution imaging of faint, extended objects in our own
and other galaxies, and of solar-system bodies, in the visible
and near-infrared spectral regions.  The workhorse of the HST
observing program, WF/PC I is seriously affected by the
aberration.  However, WF/PC I can still be used to study bright,
high-contrast objects, such as major solar-system planets and
nearby star clusters and galaxies.  The camera has already
returned spectacular images of a giant storm on Saturn (see
Figure 7) and has revealed new detail in the compact cores of two
galaxies, among many other achievements.

	The Faint Object Camera (FOC) is intended for imaging of
the faintest objects in the visible and ultraviolet spectral
regions at very high spatial resolution.  Its performance is
degraded by the spherical aberration, but the sharp image cores
still allow the FOC to detect details not seen by ground-based
telescopes.

	The current capabilities of the FOC have been extensively
demonstrated during the first months of HST operation.  For
example, the camera has imaged a high-energy jet in a distant
radio-emitting galaxy, resolved Pluto and its close satellite
Charon, probed the core of a nearby exploding star, and resolved
quasar images in the "Einstein Cross" galactic gravitational
lens.  Figures 8 and 9 illustrate other FOC accomplishments that
depend upon HST capability for high spatial resolution of bright
objects.

	Figure 8 compares a ground-based image with an FOC image
of a highly compact light source within a rich star-forming
region in the Large Magellanic Cloud (a nearby galaxy visible
from the Southern Hemisphere). This object had been suspected to
be either a very large and luminous star or a cluster of
individual stars; the FOC resolved the cluster and settled the
issue.

	Figure 9 presents another significant FOC achievement: a
detailed image of the remnant of Supernova 1987A in the Large
Magellanic Cloud, showing a complete ring structure surrounding
the exploded star.  Ground-based observations could at best
reveal only parts of the ring.

	The Faint Object Spectrograph (FOS) is designed to
analyze the light from very faint objects in the visible and
ultraviolet spectral regions.  Although the faintest objects
cannot now be reached, observations of brighter sources are only
moderately degraded.  Because most of the initial HST observing
time was devoted to imaging, the FOS only recently has begun to
demonstrate its productivity.

	The Goddard High Resolution Spectrograph (GHRS) is
intended for very detailed analysis of ultraviolet radiation.
The instrument now loses spectral resolution on the faintest
objects, but as in the case of the FOS, observations of brighter
sources are only moderately degraded.  Because HST provides a
unique capability in the ultraviolet spectral region, the GHRS is
still expected to become a highly productive instrument.

	The High Speed Photometer (HSP) is designed for accurate
measurements of light intensity and its fluctuations at temporal
resolutions of up to 100 readings per second.  Because little
observing time has so far been allocated to this instrument, the
impact of the aberration has not yet been well determined.

	The Fine Guidance Sensors (FGS) are designed not only for
accurate HST pointing, but also for astrometry--precise
measurements of stellar positions and motions.  The capabilities
of these sensors may be little affected by the aberration, but
conclusive tests are still under way.

	On balance, this assessment shows that near-term HST
programs are best directed toward brighter, high-contrast objects
and ultraviolet observations.  However, exposure times will need
to be two to seven times longer than originally planned, because
less light is now available in the core region of the image.  The
HST observing schedule will therefore be completely reorganized
in order to optimize the use of the telescope during the first
years (1991-1993) of its planned 15-year lifetime.

Servicing Plan

	The Hubble Space Telescope was designed to achieve an
overall mission lifetime of approximately 15 years through
on-orbit maintenance and repair.  From the beginning, provision
was therefore made for replacement of critical spacecraft systems
and scientific instruments.

	Although the HST primary mirror cannot be replaced on
orbit, several "second generation" scientific instruments have
long been planned as part of the HST mission strategy.  These
will eventually replace some of the current instruments in order
to extend and advance HST's scientific capability throughout its
operational lifetime.

	The first replacement instrument is the Wide
Field/Planetary Camera II (WF/PC II), which is under development.
This instrument will now be slightly modified to include its own
corrective optics--eight dime-sized relay mirrors with just
enought curvature to restore the focus of the aberrated light.
WF/PC II will be installed on HST during the first Space Shuttle
servicing mission, currently scheduled for 1993.  Additional
optical corrections designed to restore the focus of other
current HST instruments are also under review.

	Later Space Shuttle servicing missions will permit
installation of additional second-generation instruments.  These
were originally conceived to extend HST's infrared sensitivity
and add imaging capability to ultraviolet spectroscopic
observations.  Now, however, such later instruments will also,
like WF/PC II, incorporate their own corrective optics to
compensate for the effects of the aberration.  As a result of
these successive upgrades, most, if not nearly all, of the
originally planned HST observing program can be carried out by
the end of the total 15-year mission.

Article         1455
From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.tw.science,clari.news.top
Subject: Hubble Space Telescope launched one year ago
Date: 22 Apr 91 20:54:23 GMT
  
	WASHINGTON (UPI) -- One year after the launch of the ill-fated
Hubble Space Telescope, NASA officials focused Monday on the defective
observatory's accomplishments and looked forward to fixing its faulty
optical system. 
	``We have gone from what we considered a real disaster to realizing
there is still a heck of a lot of science we can do,'' project scientist
Edward Weiler said.
	The long-awaited $1.5 Hubble telescope was launched April 25, 1990,
from the space shuttle Discovery.
	Excited astronomers hoped the boxcar-sized telescope would
revolutionize astronomy by using its advanced optical system and perch
high above Earth's obscuring atmosphere to study the universe in greater
detail than ever before.
	But officials were stunned to discover that the telescope was placed
into orbit 380 miles above Earth with a misshapen primary mirror, preventing 
the telescope from focusing sharply and limiting its capability.
	An investigation subsequently determined the flaw occurred
when a technician apparently incorrectly set a device used to measure
the supposedly perfect 94-inch mirror while it was being built a
decade earlier. Results from a ground test that pointed out the flaw
were ignored. 
	``We have learned that when we have test results that show we have a
problem, we should make sure that somebody believes the results,''
Weiler said. ``We've got to have more 'checkers' and 'double-checkers'
in the system.''
	NASA hopes to fix the problem in the second half of 1993 by sending
astronauts to the telescope on a space shuttle repair mission. In
effect, the astronauts would put eyeglasses on the telescope by
installing new mirrors in front of observing instruments already on
board to compensate for the shape of the mirror.
	The spacewalking astronauts will also replace the telescope's solar
panels, which have caused vibration whenever the telescope passes from
daylight into night, install a second-generation wide field-planetary
camera and a faulty gyro system.
	On the anniversary of the telescope's launch, officials told a
nationwide telephone news conference that they looked forward to the
repairs, which should nearly completely restore the telescope to its
intended capacity.
	But they added that Hubble can complete valuable research in the
meantime despite the defect and had already chalked up a number of
important discoveries.
	``In general, we have learned over that over the past six months that
even despite the spherical aberration, Hubble is still the best
telescope in the world,'' Weiler said.
	Hubble's pictures of bright objects, like planets, are 10 times
clearer than pictures taken by the best Earth-bound telescopes, the NASA
scientist said.
	Among its accomplishments, the telescope has produced highly detailed
pictures of Mars, the Comet Levy, the planet Pluto and its moon Charon
and a gigantic storm in progress on Saturn.
	The telescope also produced the most accurate measurement of the
distance to the neighboring Large Magellanic Cloud -- an important step
toward determining the size of the universe.
	In addition, the telescope produced images of a number of other
celestial bodies, including the discovery of dozens of stars in the 30
Doradus complex where only one star was thought to be.
	Next month, NASA plans to release ``really beautiful'' pictures of
Jupiter taken by Hubble, which is expected to have a research life of 15
years to 20 years, Weiler said.
	Other projects slated for the upcoming year include taking another
peek at Saturn's surface when the planet comes out from behind the sun,
searching for black holes and using spectroscopy to study the
electromagnetic radiation from stars, galaxies and other cosmic objects.
	Currently, about half of Hubble's time is devoted to science and the
other half to engineering work aimed at fine-tuning its observations. By
November, 100 percent of the telescope's time will be spent on science,
Weiler said.
	More than 90 percent of the 100 scientific teams originally scheduled
to use Hubble are pressing on with their plans, although some have had
to reduce the scope of their projects, Weiler said.
	``Only a very few backed down and said they could not do their
science,'' he said.

HUBBLE SPACE TELESCOPE COMPLETES FIRST YEAR

4/25/91

     NASA's Hubble Space Telescope (HST) completed one year of
operation Thursday (April 25), and scientists are elated with the
results.
     The observatory was launched from Kennedy Space Center last
April 24 and deployed from the Space Shuttle Discovery the next
day.  Shortly after deployment scientists and engineers determined
that the telescope's eight-foot mirror suffered from a "spherical
aberration" that would affect the observations of the spacecraft's
five scientific instruments.  A spherical aberration prevents the
telescope from making a sharp focus.
     Although scientists at first believed the effectiveness of the
observatory would be impaired seriously, significant observations
have been made during this first year, and observing efficiency
has increased steadily, according to Joseph H. Rothenberg,
Associate Director of Flight Projects for Hubble Space Telescope
at Goddard.
     While scientists are disappointed by the limitations brought
about by the aberration, their experiences with the observatory
generally have left them pleased with the results and excited about
the science they have been able to achieve, he explained.  .
     Even with the spherical aberration, a European-built solar
array that has caused stability problems and a failed attitude
control system gyro, Rothenberg pointed out, Hubble has:
     1.  Completed orbital verification, a period designed to check
out the subsystems of the spacecraft.
     2.  Completed a significant portion of science verification,
a period for checking out and calibrating the spacecraft's
scientific instruments.  (Project officials hope to complete
science verification late this year or early in 1992.)
    3.  Released 23 images taken by the HST and the first
spectograph.
    4.  Resulted in the publication of a number of scientific
papers and the presentation of data from observations at many key
scientific meetings.
     Rothenberg said that ground controllers have developed and
installed two major improvements of the ground software without
imposing on operations and have developed onboard software which
significantly reduced the effects of solar array "jitter" affecting
spacecraft pointing control.
     During early operations, the solar arrays caused a "jitter"
in the spacecraft when it went from daylight to darkness and vice
versa.  The "jitter," which would last up to eight minutes,
prevented the spacecraft from "locking" onto guide stars, which are
used for pointing the spacecraft.
      The software used to alleviate the "jitter," developed at
Goddard and Marshall Space Flight Centers, is known as SAGA, for
Solar Array Gain Augmentation.  The software, Rothenberg explained,
reduced the frequency of the "jitter" and cut the length of time
of the vibration in half.
      Scientists plan to compensate for the spherical aberration
by modifying the telescope's replacement instruments.  The
installation of the first replacement instrument, the Wide
Field/Planetary Camera II, is planned for 1993 when a space shuttle
servicing mission is now scheduled.  Space shuttle servicing plans
call for the astronauts to replace the Wide Field/Planetary Camera,
the solar arrays and the failed gyro during three six-hour space
walks.
     There also is a possibility that a module known as COSTAR
(Corrective Optics Space Telescope Axial Replacement) might be
installed on that mission.  The module is under study by officials
from NASA, who are expected to make a decision next month on
whether it will be built and used.
     Once inserted by the astronauts, the COSTAR  device would
deploy an arm into the beam of light that passes through the hole
in the center of the primary mirror after having  bounced off the
secondary mirror.  The COSTAR then would position tiny corrective
mirrors over the apertures of the other axial instruments--the
Faint Object Spectograph, the Goddard High Resolution Spectograph
and the Faint Object Camera--and reflect "corrected" light into
them.
 

Article         1266
From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space,clari.news.gov.agency,clari.news.aviation
Subject: Hubble Space Telescope captures picture of Jupiter
Date: 6 May 91 17:00:41 GMT
  
	WASHINGTON (UPI) -- An exceptionally sharp picture of the
giant planet Jupiter taken by the Hubble Space Telescope and released
Monday shows the planet's turbulent atmosphere and the telescope's
abilities. 

	The picture of the southeast quadrant of Jupiter was captured
March 11 by Hubble's wide field-planetary camera and shows an
oval-shaped dark ring on the left and the Great Red Spot rotating out
of view on the right. 

	The features are believed to be very large hurricane-like
formations where warmer gases carry ammonia ice crystals from deep in
the Jovian atmosphere above the top of the normal clouds that shroud
Jupiter, NASA said. 

	Jupiter, the largest planet in the solar system, is 318 times
as massive as Earth. The planet is best known for the Great Red Spot,
a giant elliptical cloud system that rotates counter-clockwise. 

	The clouds on Jupiter are thought to be colored by small
amounts of sulfur, phosphorous and carbon compouds in the ice crystals. 

	The image is about as clear as those taken by the Voyager
spacecraft five days before passing Jupiter in 1979, demonstrating
Hubble's value despite its flawed optical system, said project
scientist Edward Weiler. 

	Although the picture does not reveal any new scientific
findings about Jupiter, the image demonstrates scientists will be able
to use Hubble as hoped to learn more about Jupiter's atmosphere by
observing the planet over an extended period of time, Weiler said. 

	``It shows we can do some of the cloud and motion and wind
velocity studies of the development of storms on Jupiter that we had
hoped to do over the long term,'' Weiler said. 

	Previous data about Jupiter's atmosphere collected by Voyager
was only from a couple of weeks. 

	``It's like studying Earth's weather. If you are only there
for a couple of weeks you're not going to learn much,'' he said.
``This is sort of a test image. And it looks pretty good.'' 

	The eagarly awaited $1.5 billion Hubble telescope was launched
into Earth orbit in April 1990 with the hope of revolutionizing
astronomy by studying the universe in greater detail than ever before.

	But the telescope was subsequently found to have been built
with a misshapen primary mirror that prevents the telescope from
focusing sharply, limiting its capability. 

	NASA hopes to correct the problem in 1993 by sending a space
shuttle crew to install special equipment to compensate for the flaw
in the telescope, which is orbiting 381 miles above Earth. 

	In the meantime, however, astronomers have been able to
perform more valuable research with the telescope than they initially
believed was possible when the defect was first discovered. 

	NASA previously released pictures taken with Hubble of Mars,
Pluto and its moon Charon, the Comet Levy, and a gigantic storm on
Saturn, which officials plan to study again with Hubble. 

    OK Dave, so where's that wonderful GIF picture of Jupiter that we can
    display on our workstations?  :-)
    
    ...Roger...

Article         1547
From: [email protected] (REBECCA KOLBERG, UPI Science Writer)
Newsgroups: clari.tw.space,clari.tw.science
Subject: Hubble finds new cosmic puzzles
Date: 18 May 91 01:57:09 GMT
  
	BALTIMORE (UPI) -- The Hubble Space Telescope has detected gas clouds
that appear to be from the universe's early days much nearer Earth than
previously thought possible, astronomers said Friday.
	Scientists said the finding is the $1.5 billion orbiting telescope's
most important unique contribution to astronomy to date.
	``This is a bona fide discovery no matter what way you slice it,''
said John Brandt of the University of Colorado, adding that the
achievement would have been impossible for a ground-based telescope
obscured by Earth's atmosphere.
	NASA also released pictures taken by Hubble of an unusual jet
spouting from a massive, unstable star called Eta Carinae, upsetting
existing ideas about how the star was spewing out matter. Such jets have
generally been associated with star formation rather than energy
outbursts from mature stars.
	Another fascinating result presented at a seminar at the Space
Telescope Science Institute involved detection of comet-like clumps of
material near Beta Pictoris, a star that some astronmers suspect may
have or may be developing planets.
	That research involved an analysis of invisible, ultraviolet light.
In October, Hubble is scheduled to take pictures of the outer reaches of
the disk of dust and debris surrounding Beta Pictoris in a search for
visible signs of planets. However, the telescope likely could spot only
objects bigger than Jupiter, the largest planet in our solar system,
scientists said.
	Hubble, hailed as the telescope that would revolutionize astronomy
when it was launced just over a year ago, has been hobbled by flaws in
its main mirror, a faulty gyro system and a problem with vibrations when
it passes from day into night. A shuttle mission is scheduled to repair
the telescope in 1993, but NASA scientists say valuable research still
can be conducted in the meantime.
	Unlike Hubble's most publicized recent accomplishments like highly
detailed pictures of Mars, Pluto and the Comet Levy, the discovery of
the mystifing clouds of cool hydrogen was not accompanied by pictures
because it was based on observations of non-visible light.
	In studies using light-splitting spectrographs, which are able to
detect objects invisible to the human eye by their chemical signatures,
Brandt and his Hubble colleagues found between nine and 16 thin clouds
of cool hydrogen about 1 billion light years from Earth.
	That distance is much closer than previously thought and indicates
such clouds probably persisted long after the universe's birth in a big
bang explosion some 10 billion to 20 billion years ago.
	``A new gauntlet has been thrown down and it's time to get back to
work,'' Brandt said, referring to the impact of the new finding on
efforts to understand how the universe evolved.
	Officially dubbed ``Lyman alpha'' clouds, the formations seem to be 
``little pockets of gas that never got it together to form galaxies,''
said Ray Weymann of Carnegie Institution of Washington and a leader in
the spectrograph observations.
	The size of the clouds is not known, but astronomers emphasized the
hydrogen is spread very thinly. The Hubble findings indicated such
clouds are at least five times more common in the universe than
previously thought.
	Richard Harms, of Applied Research Corp. in Landover, Md., and
also part of the Hubble scientific team, said what accounts for the
relatively nearby pools of apparently ancient gas poses ``a real mystery.'' 
	Possibilities include that the clouds were trapped by the
gravitational pull of invisible ``dark matter'' or somehow confined by
the pressure of sheets of hot, thin intergalalctic gas.
	A more far-fetched explanation is that there are forces at work in
the current era that can generate clouds of hydrogen similar to those in
the early universe.

All indications are that one of five remaining HST gyroscope sensors
failed Sunday, June 30, 1991.  Gyros maintain HST's attitude control,
with nominal control of the spacecraft requiring three gyros.
Currently the Observatory is functioning normally in the three-gyro
configuration and the timeline is proceeding as planned.

HST was launched with six gyros.  (In December 1990 HST also
experienced a gyro failure.)  If needed, the spare gyro can be
switched into the attitude control system.

The failed gyro's electronic circuitry appears to have been damaged,
possibly due to increased radiation within the South Atlantic
Anomaly, a region of high radiation environment that has
intensified due to the recent solar activity.  Data indicates that the
recent solar activity produced an unusually large proton flux.

HST controllers are currently examining whether this failure is due
to a generic problem among gyros or is unique to this occurrence.
They are actively undertaking ground radiation tests of a similar
gyro.

In the event of additional gyro failures, HST could activate its
"Retrieval Mode Gyro Package."  This package is used for placing
HST into various safemodes and/or for the STS servicing mission.

HST is designed to be fully serviceable on orbit.  Replacement gyros
are currently available and ready for the planned servicing mission.
The first HST servicing mission, tentatively scheduled for late 1993,
will replace at least one of the gyro assemblies (two gyros compose an
assembly).

Article        15449
From: [email protected] (Stupendous Man)
Newsgroups: sci.astro
Subject: Some recent experiments with HST: not so bad after all
Date: 26 Jul 91 18:05:27 GMT
Sender: [email protected] (USENET Administrator)
Organization: University of California, Berkeley
  
  I thought I'd share some information on HST I gleaned from a recent
paper and preprint.  The paper is 
 
     "Test of the Photometric Accuracy of Image Restoration using the
Maximum Entropy Method", Judith Cohen, Astronomical Journal, 101, 734
(February 1991)
 
  and the preprint
 
      "The Current Ability of HST to Reveal Morphological Structure in
Medium-Redshift Galaxies", Ivan King and eight others, to be published
in the October 1991 issue of Astronomical Journal.
 
  Both papers describe how well one can use image-restoration techniques
to compensate for the spherical aberration in HST's primary.  I was 
pleasantly surprised by the results, but daunted by the cost of achieving
them.
 
  Cohen made simulations of images that would be formed when the
Wide Field Camera of HST is used to look at moderately-crowded star
fields.  She created images using the point-spread function measured
from actual HST images, and then applied the MEMESYS3 code of Gull and
Skilling.  Note that all of her experiments dealt with point sources
of light, not extended ones.  She found that, although the deconvolution
did help to separate very close stars, it affected the photometric 
accuracy of the images quite a bit.  Comparing the actual performace 
to that expected from a mirror without aberrations, she said, 
"if one merely asks for detection ... the WFC ... is degraded by a factor
of about 4 (1.5 mag). But is one requires photometric accuracy, the
performance ... is degraded NEAR THE FAINT LIMIT (emphasis mine) by
a factor of between 10 and 15 (2.5 to 2.9 mag)."
 
  King and his coauthors, on the other hand, tried to determine how
well HST could be used to study the morphology of galaxies which are
too distant to show features in ground-based images.  They looked at
a single galaxy with the Faint Object Camera (which has a very small 
field of view, but high resolution), with two 900-second exposures,
and at a nearby field of several galaxies with the Wide Field Camera,
in a single 1800-second exposure.  They note that it is a VERY good
idea to take several short exposures with HST, rather than a single 
long one, for several reasons: first, you can easily eliminate the
many cosmic rays that mar an image if you have more than one picture.
Also, since the image restoration techniques are still considered
experimental, you can compare the results of deconvolution on several
independent images to see which features are likely to be real, and 
which artifacts of the restoration process.
 
  King et al. tried a number of techniques to restore the images to
something like their pristine form: Fourier deconvolution, Lucy-Richardson
methods, maximum-likelihood Bayesian restoration, several maximum-entropy
methods, and a version of CLEAN.  It's hard to summarize their results
briefly, but some of the important points they mention are:
 
     a. the image-restoration methods all work best on objects of
        high surface brightness; for such objects in their images,
        all the methods gave comfortingly similar results.
 
     b. for the WFC specfically, "V = 20 is certainly the limit for good
        morphological information and surface photometry in a single-
        orbit exposure ... at least ... 4-8 orbits [are needed] to do
        a reasonable job on galaxies of average surface brightness, 
        with V >= 21.5."
 
     c. again for the WFC, they estimate roughly that non-stellar objects 
        can be distinguished from stars if their deconvolved FWHM exceed
        about 0.1 arcsec, for high signal-to-noise objects, but ranging 
        up to 0.2 arcsec for objects with very low signals.
 
   The authors conclude that in the redshift range (0.2 < z < 0.5),
"HST images are capable of revealing a great deal of information about
galaxies of typical surface brightness."  Like Cohen, however, they find
that HST will need more time to reach its stated goals.  In their images,
they could find stars down to about 24th magnitude in the FOC and a bit
below 25th magnitude in the WFC (each around 1800 seconds, or one half-orbit).
 
   Let me point out that ALL the deconvolution techniques require a GREAT
DEAL of computer time: for example, the CLEAN method applied to a single
WFC image would take around 1 CPU-day on the Cray XMP they used.  Other
methods are less compute-intensive, and if you only look at subsections
of an entire 1600x1600 WFC frame, you can cut down on the computations
considerably (one big problem is that the PSF varies across a WFC image).
For example, a sophisticated maximum-entropy scheme applied to a
256x256 subimage took only 2.5 hours and a VAX 3100.  Fortunately, I
doubt many observers will be getting more than a few images!
 
--                                          Michael Richmond
"This is the heart that broke my finger."   [email protected]

NPR briefly reported that NASA is considering mounting an emergency mission
to visit HST.  Apparently the failing gyroscopes are threatening the
observatory.

- dave

  ... also I heard that it's an either or situation for HST. Either they
get the early rescue mission or they get to replace the lenses in 1993.
That from the Boston Globe so consider the source.

  George

Article         1549
From: [email protected]
Newsgroups: clari.tw.space,clari.news.gov.usa
Subject: Emergency shuttle flight considered to fix Hubble
Date: 31 Jul 91 04:09:02 GMT
  
	WASHINGTON (UPI) -- NASA is considering an emergency space
shuttle flight to save the Hubble Space Telescope from a possible loss
of control, The Washington Post reported Wednesday. 

	The troubles relate to unexplained failures in two of the
telescope's six gyroscopes and a hint of trouble in a third, the
newspaper said, citing unidentified sources. 

	The National Aeronautics and Space Administration already was
planning a repair mission for late 1993 to correct the effects of a
serious flaw built into the telescope's 94.5-inch primary mirror.
Astronauts are to replace or apply corrective optics on at least one
and possibly four of five main instruments aboard the Hubble. 

	But officials told the Post Tuesday the gyroscope problem may
be too severe to wait until the 1993 flight.  However, the complex
hardware and intricate planning required to fix the telescope's flawed
vision would not be ready in time for an earlier emergency flight,
which could occur in late 1992. 

	The officials told the newspaper they may have to choose between 
the two repairs because their budget will not allow for two flights. 

	The Hubble's gyroscopes are used to control the device's
pitch, roll and yaw so the telescope can point to any part of the sky.

	The gyroscope problem comes on top of concerns among some
structural engineers that a continuing in the Hubble's European-built
solar arrays could cause metal fatigue in the long booms that support
the panels, resulting in breakage and loss of spacecraft's power
supply, officials told the Post. 

	The European Space Agency may not be able to provide a
replacement set of solar arrays in time fo an earlier servicing
flight, officials told the newspaper. But they emphasized initial
tests indicate the panels are not likely to break before the 1993
flight. 

	The telescope was launched 15 months ago and was expected to
revolutionize astronomy by using its vantage point above Earth's
distorting atmosphere to see much finer detail than telescopes on the
ground. 

	Officials told the Post a decision on when to send shuttle
astronauts to work on the Hubble is at least a month away pending
further analysis. 

  Rather than leaving it up there with fuzzy eyes, they should consider
bringing it back down in 1992 for an overhaul. They could probably launch it
again around 1995-1997 with many factory built fixes possibly including a
new mirror.

  Long term, I bet that would result in better science since they could start
a new 15 year flight with better and fresher hardware. After all, this is a 15
to 20 year project to gather data through 4 large observatories, HST, Gamma,
X-Ray, and Infrared. Why not take it slow and do it right.

  George

You'd never get the money to do that -- or, more to the point, if you got
it down it would cost more to refurbish it than it would to build a new one.

They aren't leaving it up there with fuzzy eyes.  They have identified how
to correct for the aberration with optics placed prior to the focal plane
(there's plenty of them there already, this is "just" one more).   The fix
will require the sacrifice of the High Speed Photometer, but there is talk
around that another photometer (different design) might be piggybacked with
the optics fix, so photometry could continue.

While there isn't a total concensus in the astronomical community, a common
theme is that HST is best replaced with a number of smaller, more specialized
optical instruments - launched on unmanned vehicles [I don't know about on-orbit
servicing/retrieval requirements].  This is seen to be cheaper, less risky,
and can potentially produce better science.

The optics are starting to head into the back seat of HST's problems - even if
they were the most publicized.   If the figure of the mirror was perfect,
the doomsayers would be pointing to the solar array and gyroscopes as
fatal blows to the observatory.

They (NASA) pushed too many envelopes with HST.


- dave

  Right, but remember, the "simple fix" of the optical problem won't be ready
if they have to run a rescue mission in 1992. That means they will probably
have to go back up around 1995 or 1996 with the new camera's anyway. 

  So why not bring it down in 1992 and take it back up in 1996? They would lose
a few years, but they could take several years of lab work, rather than 3-5
days of space suit work to make repairs. Even if they were not extensive,
that sounds like better quality repairs than they will get with a couple
shuttle visits.

  By 1992 they will have taken lots of pictures for astronomers to study
showing another peal of the cosmic onion. Starting a new 15 year mission in
1996 with repaired and refreshed equipment, sounds better than continuing 
for 8 more years and depending on fixing problems with short visits.

  And since the flights are already planned, it shouldn't cost that much
more,

  George

Article         1550
From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military
Subject: More trouble for Hubble Space Telescope
Date: 31 Jul 91 16:49:49 GMT
  
	CAPE CANAVERAL, Fla. (UPI) -- Two of the Hubble Space
Telescope's six stabilizing gyroscopes have failed, a third has
problems, and jitters from flexing solar panels could force NASA to
mount an earlier-than-planned shuttle repair mission, officials said
Wednesday. 

	But space agency officials downplayed the seriousness of the
latest Hubble trouble, saying the space observatory is working
normally at present and that in any case, an unplanned repair mission
could not be mounted much earlier than 1993, when a visit already is
planned, except in a worst-case scenario. 

	``If we lose another gyroscope and we're down to three we can
still do full and normal science operations,'' said Charles Pellerin,
director of astrophysics at NASA headquarters in Washington. ``We're
pretty optimistic we can do science operations, with some loss of
efficiency, with even two gyros.'' 

	NASA already plans a late 1993 mission to install new science
instruments and corrective optics to compensate for a major flaw in
Hubble's 94.5-inch mirror that prevents the space observatory from
bringing light to a sharp focus. 

	At the same time, astronauts would replace Hubble's
European-built solar arrays, which flex and bend every time the
telescope moves out of Earth's shadow and into the heat of the Sun,
producing star-blurring jitters and possibly causing metal fatigue. 

	The problems came to light shortly after the $1.5 billion
telescope was launched from the shuttle Discovery on April 25, 1990.
Later, two of the satellite's six stabilizing gyroscopes failed,
apparently because of problems with a specific electronic ``chip.'' 

	The telescope normally operates with just three such
``gyros.'' But project managers recently decided to turn on a fourth
after one of the remaining gyroscopes began drawing more current than
normal, apparently because of dust or dirt in a rotor mechanism. 

	``Something is definitely wrong,'' Pellerin said. ``What first
caused our alarm was an over-current reading. The current is about 178
milliamps instead of 165. There's definitely anomalous behavior and we
believe the lifetime is probably limited, perhaps a year or so.'' 

	Hubble managers then began informally debating an unplanned
repair mission, possibly as early as 1992, to replace the gyros and
solar panels, assuming a new set could be built in time. A decision on
whether to ask shuttle project officials for such a mission could be
made as early as September. 

	``We would like to have a replacement set of solar arrays
before we go up for a repair mission and we're pursuing alternatives
for accelerating solar array schedules,'' Pellerin said by telephone.
``We won't know about those possibilities until the end of August. 

	``We're also continuing the failure mode analysis on the gyros
because we want to take up gyros that have the problem corrected.
We're also looking at other issues. So about September would be the
time frame that we could bring together all the engineering analysis.'' 

	Project manager Edward Weiler said the costly telescope was in
no danger of a major failure anytime soon, such as a loss of control,
even in a worst-case scenario. 

	``Even if we lost two more gyros, there's a thing called the
RMGA, the retrieval mode gyro assembly,'' he said by telephone from
the Jet Propulsion Laboratory in Pasadena, Calif. ``Those are three
mechanical gyros that can be turned on and off whenever you want. 

	``Those are there in case something really disastrous happens.
You can drop down into that mode and that will keep the satellite from
tumbling or doing anything bad.  And you can stay in that mode for
months or years.'' 

	During the planned 1993 repair mission, spacewalking shuttle
astronauts would install new solar panels, a new camera and an
instrument known as COSTAR, a complex package of small mirrors on
motorized arms that would be used by other instruments to compensate
for Hubble's optical flaws. 

	While a new wide-field planetary camera might be ready for
launch by 1992, COSTAR, which stands for Corrective Optics Space
Telescope Axial Replacement, would not. 

	``The COSTAR would not be ready until later and the wide field
is currently scheduled at a time when it would miss this (earlier)
flight,'' Pellerin said. ``But we're going to take a hard look at what
we could accelerate.'' 

	He said NASA is ``fully committed to getting those optics
fixed as early as possible,'' but it is not yet clear whether the
agency's budget would permit two shuttle repair missions so close
together or how mission priorities might stack up. 

	``You've got a range of possibilities depending on when you go
up,'' Weiler said. ``Do we need this repair mission, do we need it in
'92, can we wait until '93? We're looking at all the options. But the
important point is we have the luxury to look at options because we're
not in emergency mode at this moment.'' 

Hubble Space Telescope
Special Spacecraft Status Report

July 31, 1991


HST is functioning normally and the science timeline is proceeding as
planned.  However, on Friday July 26, 1991, an anomaly was
observed in gyroscope (gyro) number 5.  The gyro is stable and
continues to operate satisfactorily, although its control electronics are
drawing a higher-than-normal current.

A spare gyro was activated to provide another level of redundancy
within the control system.  HST now has four gyros in use; any three
can maintain the Observatory's attitude.

HST was launched with six gyros.  (In December 1990 and July 1991,
HST also experienced failures in gyro numbers 6 and 4, respectively.)
HST engineers are examining the cause of this recent anomaly, which
appears different from the previous two.

In the event of additional, multiple gyro failures, HST could activate
its "Retrieval Mode Gyro Package."  This package is used for placing
HST into various safemodes and/or for the STS servicing mission.

HST is designed to be fully serviceable on orbit.  Replacement gyros
are currently available and ready for the planned servicing mission.
The first HST servicing mission, tentatively scheduled for late 1993,
will replace at least one of the gyro assemblies (two gyros compose
an assembly).

RELEASE:  91-121 (7/31/91)



     Contrary to a news report this morning, NASA is not in the process of
planning a mission to visit the Hubble Space Telescope (HST) any earlier than
late 1993.

     There has been discussion about this possibility within the science
community because of some erratic behavior observed over the weekend in one of
the maneuvering and pointing gyros on the HST.

     Space science officials said they would ask officials of the Space
Shuttle program to help evaluate alternative servicing strategies.  No
specific request for an earlier servicing mission has been made.
 

Now one of the instruments is acting up.  Use of the Goddard High Resolution
Spectrograph's far-UV side (Side 1) has been suspended pending an investigation
into the failure of what appears to be a faulty power supply.   As this problem
is all of 48 hours old, it is difficult to assess the magnitude of it
right now -- it appears to not be a "glitch".


Gory details in: 

    pragma::public:[nasa.hst.instruments]GHRS_SIDE1_POTENTIAL_PROB_08_09_91.
            PUBLIC:[NASA.HST.DAILY]HST_STATUS_08_08_91.  (section 4.2.5)


- dave

In spite of several gyro problems over the past month, the Hubble
Space Telescope (HST) science program continued as planned with
less than 14 hours of interruption. July 1 also marked the official
start of year one of the HST General Observers cycle.

The HST has been able to maintain a full science observing schedule
while the various spacecraft problems were worked in parallel.
Activities during the month included scheduling 13 General Observer
(GO) proposals and daily observing by the Wide Field/Planetary
Camera, Faint Object Camera, Goddard High-Resolution Spectrometer
and Faint Object Spectrometer.

These instruments were used for programs involving:  new
gravitational lenses, supernova remnants, high red-shift quasars,
planetary nebula, galactic centers, stellar winds and searches for
planets around nearby stars.

Also during the past month, background and calibration
measurements as well as engineering tests were performed.
Progress was made towards completing the science verification of the
High-Speed Photometer and adding to the ongoing sky survey.

In June, one of HST's 6 Rate Gyro Assemblies (RGA), RGA #4, failed
after experiencing several episodes in which its output readings
indicated that its saturation limit had been reached.  On each
occasion, RGA #4 returned to normal operating limits without any
operator intervention.  However, on June 30, the RGA again indicated
saturation, and has not recovered to date.

The HST has continued to operate normally while analysis of the
problem was conducted.  On Friday, July 26, the RGA #5 experienced
an anomaly in which motor current stepped from its normal
operating value of 123 milliamps (a measure of electrical current) to
173 milliamps and has stayed at this level.  This condition is not
threatening to normal gyro operations and appears unrelated to
failures experienced in
gyros #4 and #6.

Preliminary analysis of RGA #5 shows that the change may have
been caused by a momentary interruption of the gyro spin motor
drive.  Based on this analysis, no further action has been taken at
this time.  The RGA #5 is being used for spacecraft control, and the
flight operations personnel will continue to monitor the telemetry.
To date, all values remain consistent with normal gyro behavior.

NASA is continuing to study these anomalies.  However, no spacecraft
safemodes were triggered by these events and no major disruption
of the science observing program has occurred.  On July 26, RGA #1
was powered and configured as a system backup.  Three gyros are
required for HST to meet its full mission and scientific data gathering
requirements.  Now, the vehicle operates with four gyros so that it
can quickly and autonomously detect a gyro failure.

Also in June, a series of erratic readings from various spacecraft
telemetry monitors occurred.  Analysis of the problem is still in
progress.   The anomalous readings appear to be attributable to a
failure in an electronic chip in a Data Interface Unit (DIU) rather than
the result of a functional failure in any of the components being
monitored.

On July 11, 1991, there was a total eclipse of the Sun along a path
across North, Central and South America. The HST orbit passed
through the eclipse shadow five times during the day.  In
anticipation of the event, several temporary modifications to the
flight software were made to insure that the spacecraft did not
interpret the loss of Sun as a spacecraft emergency.  No problems
were experienced and science observing proceeded as planned.

A combination of the new software (SAGA, or Solar Array Gain
Augmentation) and the fine tuning of the Fine Guidance Sensor (FGS)
and Fixed Head Star Tracker (FHST) parameters has greatly increased
the ability of the onboard systems to maintain fine lock on guide
stars.  This ability in turn has led to increased observing efficiency.
Loss of fine lock still occurs on approximately one out of every three
terminator crossings.

The disturbance that results in these losses is the high-frequency,
large-bandwidth solar array disturbance which is outside the control
bandwidth of the current SAGA-GA.  An upgrade to the SAGA
software is being developed that has the potential for reducing these
additional large-bandwidth effects and should be available within
the next 5 to 6 months.  In the meantime, most observing programs
are not affected by this short interruption because of careful
planning and use of the coarse track mode.

Article         1622
From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military
Subject: Hubble trouble does not warrant emergency repair
Date: 22 Aug 91 19:09:17 GMT
 
	CAPE CANAVERAL, Fla. (UPI) - An emergency shuttle mission to
replace faulty gyroscopes and solar panels aboard the Hubble Space
Telescope is not needed before a flight already set for 1993 or early
1994, a NASA official said Thursday. 

	But to be on the safe side, engineers are perfecting computer
control software that would stabilize the $1.5 billion telescope even
if all of its gyroscopes failed, keeping the costly observatory safe
until a shuttle repair mission could be mounted. 

	``The way we're thinking right now is, we don't see any reason
when we're looking at the gyros or the solar panels that we're in
imminent danger of having a catastrophic failure,'' program scientist
Edward Weiler said in a telephone interview from NASA headquarters in
Washington. 

	The Hubble Space Telescope was launched from the shuttle
Discovery on April 25, 1990. Scientists on the ground quickly
discovered the observatory's near-perfect 94.5-inch mirror had been
mistakenly ground into the wrong shape, preventing it from bringing
starlight to a sharp focus. 

	A second-generation ``wide-field/planetary camera,'' or WFPC-2, 
already was in development and engineers quickly designed changes that 
will allow it to take sharp pictures despite the flawed mirror. 

	After studying ways to modify other instruments, engineers
settled on a device known as COSTAR, a complex package of small
mirrors on motorized arms that would be used by other instruments to
compensate for Hubble's optical flaws. 

	In the meantime, the telescope's mechanical systems began having
problems. Two of the satellite's six stabilizing gyroscopes failed,
apparently because of problems with a specific electronic ``chip.''

	The telescope normally operates with just three such gyros. But
earlier this summer, project managers decided to turn on a fourth after
one of the remaining gyroscopes began drawing more current than normal,
apparently because of dust or dirt in a rotor mechanism.

	Amid this concern about the gyroscopes, engineers were
debating what to do about the telescope's two electricity-producing
European-built solar panels.  As the spacecraft sails out of Earth's
shadow and into the warmth of the Sun, the panels flex back and forth,
creating a wobble that interferes with astronomical observations. 

	When the third gyroscope began acting up, Hubble managers
began informally discussing the possibility of an emergency shuttle
flight in 1992 to install new gyros, solar panels, the
second-generation planetary camera and, if possible, the COSTAR. 

	Weiler said Thursday scientists and engineers no longer
believe such an emergency mission is necessary and that a final
decision to proceed with an already planned 1993 or early 1994 flight
was expected by late September or early October. 

	``There are several options, but the one that, in my opinion,
is the most attractive is to go up in the November-December timeframe
of 1993 as we had planned,'' Weiler said. 

	A new NASA shuttle launch manifest released earlier this week
lists a Hubble visit in 1994, but Weiler said the Hubble team hoped to
be ready for a 1993 flight if the shuttle program could support them. 

	But it is not yet clear whether all of the repair work - the
installation of four new gyroscopes, two solar panels, WFPC-2 and COSTAR
- can be done on a single shuttle mission featuring three spacewalks.

	If not, the installation of COSTAR, which stands for Corrective
Optics Space Telescope Axial Replacement, likely would be deferred to a
subsequent mission.

	``In my judgment, probably the gyros are top priority, the solar
arrays would be second priority, WFPC third and COSTAR fourth,'' Weiler
said.

	He said an earlier repair flight has been all but ruled out
because of studies that indicate the solar panels will not break,
despite their flexing, before 1993 and that Hubble's remaining
gyroscopes should continue to work properly. 

	``In the meantime, we've been developing a method of
controlling the spacecraft with no gyros in case something really bad
happens, where you use magnetometers on board, plus perhaps a sun
sensor or a star tracker to control three axes,'' he said. ``If we had
to go to the zero gyro mode we would not be able to do science. But we
could keep it safe until a shuttle gets there.'' 

	The ``zero gyro control law'' computer software should be
finished later this fall. After that, engineers will press on with
computer programming that would allow Hubble to continue gathering
science with just two gyroscopes. 

.226>>	A new NASA shuttle launch manifest released earlier this week
.226>> lists a Hubble visit in 1994, but Weiler said the Hubble team hoped to
.226>> be ready for a 1993 flight if the shuttle program could support them. 

Anyone happen to have this available (preferrably online)?

...Roger...

    Re: ,227
    
    Patience.  It's on its way...
    
    - dave

... I'm a little anxious to see what the latest launch date "estimates" are
for the next few shuttle launches.  I'll be in Florida during the first couple
of weeks in December and was hoping I might get lucky and be there when one of
the birds is scheduled to fly.

...Roger...

Sky and Telescope this month, (the 50th anniversary issue), describes the
problems with the high resolution spectrograph. The power supply for one side
of the instrument has gone south, unfortunately this supply also powers the
interface electronics rendering the whole instrument inop.

Under fixes, the article says that it is possible to reconfigure the instruement
to use interface electronics powered by the good supply ...but... all the
other instruments would have to be reconfigured as well. This would involve
shutting them down then powering them up on the other bus. Somebody was quoted
as saying that probably wasn't a good idea because stuff tends to break when
configurations are changed. There was also discusion about having the repair
mission patch in another supply, but they didn't think they would have enough
time on orbit to do all the repairs needed already.

Mike H

Article: 17278
From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Hubble Space Telescope Monthly Status Report
Date: 3 Oct 91 05:29:00 GMT
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
 
Forwarded from the Spacelink BBS
 
                       HST MONTHLY STATUS REPORT  
                           September, 1991
 
      The Hubble Space Telescope (HST) continued to operate normally
 under four-gyro control. All scientific instruments except the Goddard
 High Resolution Spectrograph (GHRS) continue to produce science data.
 The GHRS Science Data Formatter (SDF) interface continued to exhibit
 periodic anomalous behavior that has resulted in data losses and
 program interruptions.  A test scenario has been developed to exercise
 the SDF over varying orbital thermal conditions to characterize the
 problem.  The testing will be able to run in parallel with other
 instrument programs and thereby not impinge on observational
 efficiency.  The current efficiency is running approximately 30 per
 cent (ideal level is 35%) and improving as each instrument completes
 verification procedures and is able to define requirements better for
 observing parameters and timing.
 
      The scientific community is enthusiastic over the data that HST is
 producing, according to project officials.  The latest request for
 proposals for Cycle Two observing (July, 1992-July, 1993) produced more
 approximately 500 submissions from 26 different countries.  Of those
 submissions, eight were proposals to do research on non-proprietary
 data from HST's first year of operations.
 
      Planning for the 1993 servicing mission is well underway.
 Schedules and contracts are in place for the delivery of the Wide
 Field/Planetary Camera II (WF/PCII), Corrective Optics Space Telescope
 Axial Replacement (COSTAR), rate gyro assemblies and solar arrays.
 Several joint reviews were held during the month with the European
 Space Agency (ESA), and modifications being made to the (ESA) Solar
 Array II should reduce many of the causes of jitter that HST currently
 experiences, officials said.
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |     Jet Propulsion Lab |
  ___| | | | |__) |/  | | |__   M/S 301-355 Telos  | For every rule, there is 
 /___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | an exception. There is no
 |_____|/  |_|/       |_____|/                     | exception to this rule.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                  October 16, 1991

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

RELEASE:  C91-oo

        NASA's Goddard Space Flight Center, Greenbelt, Md., has awarded a
contract to the Ball Corp., Boulder, Colo., to complete construction of the
Corrective Optics Space Telescope Axial Replacement (COSTAR) for the
Hubble Space Telescope (HST).

        COSTAR was recommended by the HST Strategy Panel members from
more than 50 options.  The first opportunity to install the COSTAR is during
a servicing mission currently planned in early 1994.  This contract award is
part of a definition and development process, the results of which will be
confirmed early next year.

        Using a set of 10 small mirrors and mechanisms to position and
support the mirrors, COSTAR is designed to correct the Hubble Space
Telescope's spherical aberration.  The correction is intended to restore
significantly the scientific potential of three major instruments on board the
observatory -- the Goddard High Resolution Spectrograph, the Faint Object
Spectrograph and the Faint Object Camera.

        Ball was given a letter contract to start work on the project last
February.  Under the contract, Ball is to have the instrument ready for
delivery to NASA, with acceptance tests passed, by April 1, 1993.  This
award brings the total contract value to $30.4 million.

        "COSTAR is like putting a pair of glasses on the Space Telescope,"
explained Robert Kirk, a Goddard Procurement Manager.  "Using 10
different mirrors about the size of a quarter, COSTAR will be able to correct
the aberration-affected light from the primary mirror, sending the light on
to the three instruments that suffer from the aberration."

From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Date: 22 Oct 91 20:28:33 GMT

	CAPE CANAVERAL, Fla. (UPI) -- Scientists are increasingly confident a
$40 million to $50 million repair job in late 1993 or early 1994 will
correct the optical and mechanical defects hobbling the Hubble Space
Telescope, officials said Tuesday.
	In the meantime, astronomers around the world are using the $1.5
billion observatory to conduct world-class science studying targets that
are not terribly affected by Hubble's blurry vision, the result of a
microscopic defect in the telescope's 94.5-inch primary mirror.
	The Hubble Space Telescope was launched from the shuttle Discovery 18
months ago Friday, on April 25, 1990. Despite the spherical aberration
that prevents the main mirror from bringing starlight to a sharp focus,
program scientist Edward Weiler said the light at the end of the tunnel
is increasingly clear.
	``Before launch when we talked about the science in HST, I guess we
were ... going to go up there and hit the science home run,'' he said. 
``Contrary to what you might hear, we haven't struck out. I think we've
hit a good solid base hit and I'm pretty damn confident that come late
'93 or early '94, we're going to score.''
	That is when the National Aeronautics and Space Administration plans
to mount an ambitious shuttle repair mission requiring astronauts to
complete at least three six-hour spacewalks to install corrective
optics, a new camera, two new solar panels and four gyroscopes to
replace units that have failed.
	The spacewalkers might also be asked to install or wire in a
replacement power supply needed to restore one of Hubble's major science
instruments to full operation.
	While the details are not yet final, engineers are confident the
hardware will be ready in time for a late 1993 repair mission.
	``Right now ... we have a doable schedule,'' said Joseph Rothenberg,
a top manager at NASA's Goddard Space Flight Center in Greenbelt, Md.
	The 25,500-pound Hubble Space Telescope, the most expensive satellite
ever built, was designed to study the heavens with 10 times the clarity
of ground-based instruments, opening a new window on the universe.
	But shortly after Hubble reached orbit, engineers discovered that its
primary mirror had been ground into the wrong shape, preventing it from
bringing light to a crisp focus.
	Making a bad situation worse, engineers had trouble keeping the
telescope steady in space. They later discovered that Hubble's European-
built solar arrays flex and bend up to three feet every time the
telescope moves out of Earth's shadow and into the heat of the sun,
producing star-blurring jitters.
	In addition, two of the satellite's six stabilizing gyroscopes
failed, along with the power supply used by a critical spectroscope, one
of Hubble's primary instruments.
	Engineers have been able to improve Hubble's blurry vision with
computer processing on the ground. At the same time, changes to the
telescope's on-board programming have minimized the effects of the solar
panel flexing by applying the opposite force to the satellite when such
bending is detected.
	``The software basically takes out the jitter,'' Rothenberg said. 
``We've reduced the jitter by a large factor. We intend to reduce it
more with the new software.''
	But those are stopgap measures and Weiler said engineers and
scientists are optimistic the shuttle repair mission now planned for
late 1993 or early 1994 will correct virtually all of Hubble's troubles.
	The observatory is equipped with five primary instruments: a wide
field/planetary camera; a faint object camera; two spectroscopes; and a
sophisticated light meter called a high-speed photometer.
	The photometer will be replaced during the repair mission by a device
called COSTAR, a complex assembly of motorized mirrors that will
counteract the effects of the primary mirror's spherical aberration,
directing focussed light to the faint object camera and the
spectroscopes.
	The wide field/planetary camera will be replaced with an improved
version that has built-in corrective optics. Engineers recently settled
on a design that is less efficient than had been hoped, but one that has
a better chance of being completed in time for the repair mission.
	The cost of COSTAR and the modifications to the wide field/planetary
camera is $40 million to $50 million.
	The shuttle spacewalkers also plan to install two new European solar
panels, provided at no cost by the European Space Agency, and two sets
of replacement gyroscopes. The gyroscopes will come from an already
established spare parts program and as such will not add to the price
tag.

Jim Elliott                           November 6, 1991




       NASA'S HUBBLE SPACE TELESCOPE MONTHLY STATUS REPORT
                        FOR OCTOBER 1991

     The Hubble Space Telescope (HST) continues to operate normally
under four-gyro control, using gyros 1, 2, 3 and 5.  On October 26,
Gyro #4, which has been saturated and off-line since June 30, began
displaying nominal values on both its analog and digital rate
monitor.  Subsequently, on November 4, Gyro #4 again went off line.
Even though it came back on for short periods, it was never used in
the control loop.  Flight operations personnel will continue to
monitor its performance.  The status of Gyro #6, which failed last
December, remains unchanged.
     On October 7, flight operations personnel initiated
operational procedures to transition the Tracking and Data Relay
Satellite-West (TDRS-West) support from the TDRS-C spacecraft to
the recently-deployed TDRS-E.  The transition went smoothly.
     On October 11, Goddard Space Flight Center formally signed a
contract with Ball Corporation, of Boulder, CO for completion of
the Corrective Optics Space Telescope Axial Replacement (COSTAR).
Development at Ball is on schedule for a servicing mission in early
1994 with a Critical Design Review scheduled for December 1991 and
a planned delivery to NASA in April 1993.
 The HST science program has initiated some unique cosmological
observations using remote quasars as background sources.
Scientists working with both the Goddard High Resolution
Spectrograph (GHRS) and the Faint Object Spectrograph (FOS) have
reported detection of Lyman-alpha forest absorption in low, red-
shift quasars, and the FOS is obtaining data with important
implications for understanding the quasar emission process.  In
addition, the GHRS--in cooperation with the International
Ultraviolet Explorer (IUE) and ground-based observers--has obtained
correlative data on the flare star AU Mic.  Results from these and
other observations will be presented at the upcoming American
Astronomical Society (AAS) meeting in Atlanta in January 1992.

The observatory continues to operate normally under a four-gyro
configuration using gyros 1, 2, 3, and 5.  On November 3, gyro 4
again went into saturation and continues to behave erratically
showing saturated values when entering the night portion of the
orbit.  The erratic behavior of this unit does not impact the
current four-gyro configuration under which the observatory is
being operated.  The Flight Mission Operation engineers continue to
monitor all gyro parameters and activities.

Science programs are being implemented on a routine basis using the
Wide Field/Planetary Camera (WF/PC), the Faint Object Camera (FOC),
and the Faint Object Spectrograph (FOS).  The Goddard High
Resolution Spectrograph (GHRS) is undergoing extensive engineering
tests to determine the frequency and thermal correlation of the
science data interface failures that the GHRS has been
experiencing.  The Science Operations Team hopes to be able to
start scheduling GHRS science observations by late December.

During the month of November, Science Operations scheduled 18
General Observer programs in addition to instrument science team
observations, instrument calibrations, sky surveys and engineering
tests.  The science teams report success in observing spatially
complex objects through a strategy of using either the FOC or the
WF/PC to obtain sharper spatial information than can be gotten from
the ground to identify scientifically interesting features on a
sub-arcsecond scale and then taking spectra of the selected areas
with the FOS.  One such program in progress is observation of the
bulge and nucleus of M31.
 

Paula Cleggett-Haleim
Headquarters, Washington, D.C.             December 12, 1991



RELEASE:  91-204

        The Hubble Space Telescope (HST) resumed science data collection at 7
a.m.  EST this morning.  For the past 24 hours, the spacecraft has been safely
returning from a standby condition which began Dec. 9 at 7:47 a.m.

        Standby conditions, or safe modes, are a capability built into all NASA
spacecraft.  Safe modes are invaluable "safety nets" to protect against
spacecraft anomalies caused by on-orbit hardware problems or erroneous commands
sent from the ground.

        A subtle error in the ground software system that generates command
sequences for HST triggered this event.  The error caused an incorrect command
to be sent, which made the high gain antenna slew at a rate beyond allowable
limits.  The onboard flight computer sensed this "out-of-range" rate and put
the spacecraft in a standby and safe condition.

        According to Dr. Charles Pellerin, Director for NASA's Astrophysics
Division, "The HST flight system functioned exactly as designed and protected
itself from human errors on the ground."

        This particular type of anomaly is the first since launch of HST in
April of 1990.  The last time HST was in a safed mode of operation was in May
1991 due to a different type of computer anomaly.

        Corrections in the ground software are being worked and interim
guidelines are in place for manual inspection of command loads to ensure
against any repetition of this particular problem.

        The level of standby HST was in, called an "inertial hold mode," is the
most benign of several levels of safe configurations.  When initiated, it
basically stops executing further commands, maintains current spacecraft
attitude and alerts controllers to a potential problem.  This gives ground
personnel time to evaluate the situation, analyze the telemetry and start
appropriate actions.

Article: 1775
From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.military,clari.news.aviation
Subject: Hubble glitch caused by ground problem
Date: 11 Dec 91 19:36:42 GMT
 
	CAPE CANAVERAL, Fla. (UPI) -- A ``bug'' in a computer program
used on Earth to help control the Hubble Space Telescope knocked the
satellite out of action Monday, but officials said Wednesday the
costly observatory would be back in operation Thursday. 

	``This is one of those cases where the spacecraft once again
protected itself from the humans on the ground who wrote the software,''
Hubble project scientist Edward Weiler said by telephone from
Washington.

	The $1.5 billion Hubble Space Telescope, the most sophisticated
astronomical satellite ever built, was launched from the shuttle
Discovery on April 25, 1990.

	Since then, ground controllers have struggled to overcome a
variety of technical problems, ranging from trouble with the
satellite's stabilizing gyroscopes to instrument problems and an
unexpected jitter caused by solar panel flexing when the spacecraft
passes from Earth's shadow into sunlight. 

	The most serious problem, however, involves Hubble's main mirror.
Shortly after launch, engineers discovered the mirror had been ground
into the wrong shape, one that prevents it from bringing starlight to a
sharp focus.

	NASA plans a 1993 shuttle repair mission to install corrective
optics, new solar panels and replacement gyroscopes that should restore
the satellite to design specifications.

	In the meantime, astronomers are using Hubble to make observations
that are not severely affected by its flawed optical system. Science
data is transmitted to Earth using two ``high-gain'' antennas that beam
radio signals to a pair of NASA communications satellites.

	At 7:47 a.m. EST Monday, Hubble's on-board computer shut the
telescope down, throwing the spacecraft into a form of electronic
hibernation called a ``safe mode.'' The telescope is programmed to enter
safe mode whenever a major problem is detected.

	Weiler said the problem Monday developed because of a software
glitch on the ground that had gone undetected since launch. 

	As Hubble orbits the Earth, its two high-gain antennas track
the NASA communications satellite high above. When one such satellite
disappears behind the limb of the Earth, computer programs on the
ground calculate where the antennas should move to pick up the next
satellite. Those commands then are radioed to Hubble and executed as
required. 

	Because of a bug in the ground software, Weiler said, the
antenna was commanded to the wrong position on Monday. 

	When Hubble's on-board computer checked the antenna's position
later, it discovered the problem, ``found the antenna in the wrong
place ... and it commanded (the antenna) to go over there and get
there fast.'' 

	But safety provisions built into the telescope's on-board
programming will not permit the antenna motors to exert more than a
certain amount of force to prevent any possible damage. 

	When Hubble's electronic brain attempted to correct the antenna
problem Monday, it caused the motor to work hard enough to violate the
safety limits.

	``We entered what we call a soft safe mode on Monday at 7:47 a.m.,''
Weiler said. ``The reason we entered safe mode is ... the sensor that
senses torque on the antenna motor said it was up to 10 inch-ounces of
torque. That is the limit where the software will say stop, I'm going
into safe mode.''

	He said the ground software is made up of three million lines of
computer programming ``and as usual when humans build something, they
left a few bugs in it. This bug has been there since launch. This was
not a spacecraft problem.''

	He said the problem was identified Tuesday and that Hubble
would be back in full operation Thursday. 

                    HST MONTHLY STATUS REPORT
                          DECEMBER 1991


Hubble ended 1991 in good health and with promise for a productive
New Year in 1992.

The safemode entry that occurred on December 9 was the result of a
minor ground system's error.  The evaluation, recovery, and return
to normal science operations was accomplished within 72 hours of
the initial incident and all operations are normal.

The Goddard High Resolution Spectrograph (GHRS), which had
suspended scientific observing due to a date transfer anomaly, is
back on line and has successfully completed 36 observations during
the month without a recurrence of the interface anomaly.  Several
months of extensive testing led to a recommendation by the
engineering, operations and science teams to keep the side 2 low
voltage power supply continuously powered up.  This in turn
maintains a thermal balance that makes it possible to operate the
GHRS with reliable science data transfers.  New command and
safemode procedures are being implemented to support this
configuration and the GHRS will be routinely scheduling its science
programs starting in January.

The Astrometry Team completed a number of verification tests
necessary to calibrate the Fine Guidance Sensors for use in
astrometric science programs.  One particular test caught the
interest of both the science and mission operations teams.  The
lateral color test calibrates the instruments for color effects and
uses two different spectral type stars, one red and one green.
Since the test was scheduled for December 25 the teams dubbed the
target "The Christmas Pair."

On December 10-12, a Critical Design Review (CDR) was held on the
Servicing Mission COSTAR instrument.  The Review Board reported
confidence that the COSTAR can successfully be built as designed
and that there exists no "show stopper" issues to prevent readiness
for a 1993 Servicing Mission.

Looking forward to 1992, January will see the implementation and
testing of HST's parallel science capabilities.  Initial programs
will see the WF/PC and the FOC executing programs in parallel.
February promises an exciting series of coordinated observations of
Jupiter by the HST and Ulysses.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                January 13, 1992

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

Dr. Doug Duncan
Space Telescope Science Institute, Baltimore, Md.

RELEASE:  92-5



        Using a unique capability of NASA's Hubble Space Telescope (HST),
astronomers announced today that they have detected the rare element boron in
an ancient star.  This element may be "fossil" evidence of energetic events
which accompanied the birth of the Milky Way galaxy.  An alternative
possibility is that this rare element may be even older, dating from the birth
of our universe.  If so, then the HST findings may force some modification in
theories of the Big Bang itself.

        Dr.  Douglas Duncan, of the Space Telescope Science Institute in
Baltimore, Md., and Drs. David Lambert and Michael Lemke, of the University of
Texas, Austin, announced their results today to a press conference at the 179th
meeting of the American Astronomical Society in Atlanta. The research will be
presented to the meeting of the society in a session for late papers on
Thursday, Jan. 16.

        The light from boron only appears in the ultraviolet part of the
spectrum and so does not penetrate Earth's atmosphere. "That's why no one was
able to make this discovery before,'' says Dr. Duncan. "Having a powerful
telescope high above Earth's absorbing atmosphere has given scientists a new
window on the universe.  This was always considered to be one of the most
important reasons for building the Space Telescope."

        Using HST's Goddard High Resolution Spectrograph, the researchers
detected traces of boron in a yellow 7th magnitude star called HD 140283,
located 100 light-years away in the constellation Libra. At an estimated age of
15 billion years, the star is one of the oldest known.

        Because it was among the first stars to form in the Milky Way galaxy,
HD 140283 should contain elements which were incorporated into the star long
ago.  Preserved in the star for billions of years, such material offers clues
to conditions of the early universe when the star formed.

        Predictably, HD 140283 contains mostly primordial elements synthesized
in the Big Bang, such as hydrogen, helium and traces of lithium.  Heavier
elements such as carbon, nitrogen, oxygen and others found in the Sun, the
Earth and Solar System planets are thought to have been built up during the
lifetime of the galaxy by nuclear reactions in successive generations of stars.

        The discovery of boron comes as a surprise, however.  Previously,
another rare element, beryllium, had been detected in the star with
ground-based telescopes.

        The key question is from where did the beryllium and boron come.
Scientists know that today, beryllium and boron are produced by cosmic rays,
high-speed and extremely energetic particles which occasionally collide with
atoms in interstellar space and split them apart into lighter elements.  If
substantial amounts of beryllium and boron, the fourth and fifth lightest
elements, were formed very rapidly early in the history of the Milky Way,
swarms of energetic particles may have been present at the birth of the galaxy.
The cosmic rays could have been produced by supernovas or other highly
energetic events which occurred early in the life of the Milky Way.

        However, the astronomers found slightly different relative proportions
of beryllium and boron than what is expected from cosmic ray production.  This
offers the alternative possibility that beryllium and boron were synthesized in
the first moments of the universe's creation.

        The currently accepted version of the Big Bang says that the early
universe was uniformly hot and dense.  However, more recent theories suggest
that the Big Bang developed some structure even during the first few minutes.
These new theories differ from the traditional one in predicting that small but
detectable amounts of beryllium and boron might be created.

        To confirm these results, the astronomers plan additional HST
observations of an even older star later this year.  If the boron was produced
by cosmic rays within the young Milky Way, it should diminish the farther back
in time the astronomers look, hence closer to the birth of the galaxy.  If,
instead, astronomers find the same amount of boron in the older star, rather
than less, the finding will support the alternative explanation that boron was
produced in the Big Bang.

        "Either way, this will be an exciting test to show which of the
possible explanations is correct," concludes Duncan. "We know that our picture
of the beginning of the galaxy and the beginning of the universe is undoubtedly
oversimplified, and it is satisfying to be able to add a little more detail."

Paula Cleggett-Haleim
Headquarters, Washington, DC        January 13, 1992

Fred McGehan
National Institute of Standards and Technology,
Gaithersburg, Md.

RELEASE:  92-2

        A team of scientists using NASA's Hubble Space
Telescope (HST) has made the most precise measurement to
date of the percent of heavy hydrogen in space, which
better determines the physical conditions present in the
theorized Big Bang at the origin of the universe.

        The team's findings were presented today at a press
conference at the American Astronomical Society's
semiannual meeting in Atlanta.  The group is headed by
Jeffrey Linsky, a National Institute of Standards and
Technology (NIST) astronomer and a fellow of the Joint
Institute for Laboratory Astrophysics (JILA), a
collaboration of NIST and the University of Colorado in
Boulder.  The Hubble Space Telescope is a cooperative
project of NASA and the European Space Agency.

        Deuterium, also called heavy hydrogen, differs from
ordinary hydrogen by having one neutron in addition to one
proton in its nucleus.  A measurement of the ratio of
deuterium to ordinary hydrogen provides a critical test of
conditions in the universe at the time of the Big Bang
because it is believed that essentially all of the
deuterium now present was created at that time.

        Linsky and his collaborators used the HST's Goddard
High Resolution Spectrograph to observe the nearby star
Capella, the brightest star in the constellation Auriga and
the universe's sixth brightest star.  With the highest
spectral resolution possible on the Hubble Space Telescope,
the scientists dispersed the far ultraviolet light of the
star where the strongest absorption by normal hydrogen and
deuterium occurs.

        The so-called "Lyman alpha" lines of hydrogen and
deuterium are located next to each other in the spectrum.
These dark lines are formed when starlight is absorbed by
very low density interstellar gas located in the line of
sight toward Capella.

        A careful analysis of the two absorption lines
indicates the ratio of deuterium to hydrogen in space is 15
parts per million with an uncertainty of less than 10
percent.  This ratio is lower than the ratio in the early
universe because of the destruction of some deuterium in
the cores of stars and the subsequent dispersal of this
deuterium-poor gas into space by stellar winds and
supernova explosions.

        Deuterium has been observed in space previously by the
Copernious and International Ultraviolet Explorer
satellites.  It also has been observed by radio telescopes.
But the new measurement by the Hubble Space Telescope
greatly reduces the uncertainty in the deuterium abundance.
This permits a clear test of the creation of elements in
the early universe.

        If the assumptions of the Big Bang theory for the
early universe are correct, the deuterium-to-hydrogen ratio
in space today determines the maximum possible amount of
ordinary matter that can be present in the universe.  This
amount of ordinary matter is at least a factor of 10 too
small for the universe to be described by the ordinary laws
of geometry and for the observed expansion to be halted
eventually by gravity as some cosmologists believe.  If
enough matter in other forms does exist to eventually halt
the universe's expansion, then this missing or "dark
matter" must exist in an exotic form.

        If further research finds no evidence for large
amounts of "missing matter," then the new deuterium
measurements strengthen the idea that the universe will
expand forever.  If true, the universe had a brilliant
beginning but will have no end.

        The team of astronomers presenting this work also
includes Alexander Brown and Kenneth Gayley at JILA; Wayne
Landsman and Sara Heap at NASA's Goddard Space Flight
Center, Greenbelt, Md.; Blair Savage and Athanassios Diplas
of the University of Wisconsin, Madison, Wis.; and Thomas
Ayres of the University of Colorado.  Jack Brandt of the
University of Colorado is the principal investigator of the
Goddard High Resolution Spectrograph Program.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                              January 13, 1992

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

Dr. John Bahcall
Institute for Advanced Study, Princeton, N.J.

RELEASE:  92-4


        Astronomers reported today that recent ultraviolet observations with
NASA's Hubble Space Telescope (HST) suggest that what were thought to be
randomly distributed, nearby primordial clouds of hydrogen may actually be
associated with galaxies or clusters of galaxies.

        "This is a revolutionary finding, if supported by future observations,"
says Dr. John Bahcall of the Institute for Advanced Study in Princeton, N.J.
"We would have never thought of looking for this explanation if it hadn't
kicked us in the face."

        Drs.  Bahcall, Buell Jannuzi and Donald Schneider, all of the Institute
for Advanced Study, and George Hartig of the Space Telescope Science Institute,
Baltimore, Md., announced their results today to a press conference at the
179th meeting of the American Astronomical Society in Atlanta.

        For the past 2 decades, observations with ground-based telescopes have
shown that the spectra of high-redshift quasars contain complex "thickets" of
absorption features.  These absorption lines are unrelated to the quasars
themselves, but are attributed to invisible, intervening clouds of hydrogen gas
which absorb certain frequencies of a quasar's light.

        Ground-based observations have shown that the number of these clouds
rapidly rises as one looks back in time, so it was thought, says Hartig "that
the number of nearby hydrogen clouds was relatively small."


        Until the launch of the Hubble Space Telescope (HST), it was impossible
to directly measure the numbers of nearby clouds.  This unusual situation,
understanding the distant clouds more than the nearby ones, arose because, as
Jannuzi explains, "The recession velocity of the nearby clouds is so low that
the hydrogen absorption features occur in a part of the spectrum, the far
ultraviolet, that is inaccessible with ground-based telescopes."

        However, the HST dramatically changed this picture in 1991 when
independent observations made with the HST's Faint Object Spectrograph and
Goddard High Resolution Spectrograph detected more than a dozen hydrogen clouds
within less than a billion light-years of the Milky Way galaxy.

        Astronomers have assumed that the clouds are strung along the line-
of-sight to a quasar, like beads on a string.  The new HST observations show
that some absorption lines are more clumped together than expected for randomly
distributed material.  In addition, a few of the lines can be directly
associated with galaxies that lie along the line of sight to the quasar.  This
suggests that the material producing the nearby hydrogen absorption may be
associated with individual galaxies or clusters of galaxies.

        The new results are based upon Faint Object Spectrograph observations
of a bright and relatively nearby, approximately 4 billion light- years
distant, quasar H1821+643. "We are very pleased with the quality of the data,"
says Hartig. This spectrum shows a higher than expected number of extragalactic
absorption features, confirming the initial HST results.

        One grouping of lines in the complex spectrum has the same redshift and
hence, the same distance as the quasar.  These types of lines, called
self-absorption systems, have been found in high-redshift quasars and were
thought to be produced by material in the quasar itself.  Schneider notes that
"Recent ground-based studies have shown that H1821+643 is surrounded by a large
number of galaxies, so it is possible that the self- absorption system is
caused by material belonging to the cluster or to an individual cluster
galaxy."

        The HST observations provide additional evidence that the absorption is
associated with galaxies.  A foreground galaxy that lies along the line of
sight to the quasar has the same distance from Earth as does one of the cloud
groupings.  The cloud may be located within 300,000 light-years from the center
of the galaxy.  HST spectra of other nearby quasars are being obtained to see
if there is additional evidence of clumping of the hydrogen clouds or if any
other absorption systems can be identified as belonging to galaxies.  If so,
then one of astronomy's many current mysteries at last be may solved.

  The Boston Globe reported today that by observing ultraviolet light, the HST
has detected a heavy element in a very old star who's birth would have been
shortly after the "big bang" 15 billion years ago. If I recall correctly, the
element was barium but I'm not sure. 

  By looking at stars a long distance off, the HST effectively looks back in
time since it is viewing the light from a star that existed when the light left
the source back near the birth of the Universe. The finding disrupts the theory
that only light elements were created by the "big bang" and that heavy elements
were created by the super novas at the end of the life of 1st generation stars.
If the estimated age of the Universe is correct, then this would be a 1st
generation star that contained a heavy element. 

  The article also talked about the clumping mentioned in the last few notes.
One remark was that the "big bang" theory itself seems to be holding up
very well with regard to the new information coming from HST, even if some
other theories are having problems.

  George

      The element detected was boron, while beryllium was earlier detected
    from the ground. The star is not a long way off in astronomical terms,
    only 100 light years. It must be rather small, (probably quite a bit
    smaller than the sun) since large stars are relatively short lived.
    
    Ken

    Re:.243
    
    	I haven't been able to get much data on this particular star (yet)
    but from another press release I saw it mentioned that the star was
    magnitude 7. At a distance of 100 light years that would give the star
    an absolute magnitude of around 4.6 making it about 30% brighter than
    the Sun. If I were to make a geuss based on its age and brightness (and
    not knowing its spectral type), it was probably originally a K type
    star slightly less massive than the Sun that is nearing the end of its
    life and has begun brightening and moving off the main sequence.
    
    				Drew
    

  So how old would this star be? They seemed to imply that the light they
were getting was generated shortly after the big bang making it a 1st generation
star, hence the heavy element disproved the theory heavier elements were
only created by super novas.

  Yet if it's that close, then it must be a pretty old star.

  George

    Judging from the reports in this topic, the Hubble doesn't seem to be
    as bad as everyone makes it out to be.  I can't understand why everyone
    dumps on it?

  Everyone doesn't dump on it. The press dumps on it because they like to
give negative reports about the Space Program in general. After all, something
not working or a "waste of taxpayers money" sells copy.

  Also, it failed to produce pretty pictures which they could print. UV
pictures in print or on TV just don't seem realistic enough to wow people in
big numbers the way a visible light picture can.

  George

Hubble was supposed to generate 100 "ground-shaking" discoveries over its
lifetime.

HST in its current condition can only generate 50 or so of these discoveries.

With the fix in 93, HST should be able to generate 85-90....

The press gave/gives the impression that the number "would be around 0, well
maybe 2 or 3".


The actual numbers above are somewhat silly, but they may well represent
the proportions of science value HST was/is expected to provide.   When you
combine this with the original Space Telescope goals of 150-200 "spectacular
discoveries", and a price tag that went way beyond the original budget by
a factor of 2 or so -- a lot of people were (and are) very bitter.


The trouble with Hubble is not all the wonderful things that it will discover
over the next decade -- it's all the things it promised to discover, but
can't.

There were a large number of people working on HST, some of them for 20 years
(a few for nearly 40!).  They fought very hard for this instrument, and
brought it back from fiscal death a couple of times.  And then, the one
component that was time and time again described as "perfect" (or "most
perfect") had a near fatal flaw in it.   If the mirror was really perfect
and WF/PC or HSP didn't work - it would have been a setback, but a recoverable
one (and the press probably wouldn't have gone after it like a pack of
wolves) --- but it was the &^%$ mirror!    Can you imagine how those people
felt after putting most of their lives into this toy?   This commitment to
a project produced, I'm sure, honest anguish or anger amongst many of them.
The press feeds on this stuff like a vampire takes to blood....  We get to
hear the "good stuff" -- you really have to hunt for the real story.

Kinda makes you wonder about all the other news you hear - eh?


- dave

Paula Cleggett-Haleim
Headquarters, Washington, D.C.         January 16, 1992
                                         9:30 A.M. EST

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

Dr. Tod Lauer
National Optical Astronomical Observatories, Tuscon, Ariz.

Dr. Sandra Faber
University of California, Santa Cruz

RELEASE:  92-10

     Astronomers reported today that they have found
intriguing evidence that a black hole, weighing over 2.6
billion times the mass of the sun, exists at the center
of the giant elliptical galaxy M87, based upon images
taken by NASA's Hubble Space Telescope (HST).  The
images show that stars become strongly concentrated
towards the center of M87, as if drawn into the center
and held there by the gravitational field of a massive
black hole.

     These results were reported at the 179th meeting of
the American Astronomical Society in Atlanta by Dr. Tod
R. Lauer, National Optical Astronomy Observatories
(NOAO), Tuscon, Ariz.; Dr. Sandra M. Faber, University
of California, Santa Cruz; Dr. C. Roger Lynds, NOAO, and
other members of the HST Wide Field/Planetary Camera
(WF/PC) Imaging Team.

     M87 is at the center of a nearby cluster of
galaxies in the constellation of Virgo, 52 million
light-years distant, and contains more than 100 billion
stars.  One of the brightest galaxies in the local
universe, M87 is visible in even small telescopes.

     Early in this century astronomers discovered a
gigantic plume or "jet" of plasma apparently ejected out
of the M87 nucleus.  Later, the jet and nucleus were
found to emit strong radio and X-ray radiation.
However, the nature of the central "engine'' of this
activity has long remained a mystery.

     In 1978, the late Peter Young, California Institute
of Technology, leading a team of astronomers, announced
that the central portions of M87 visible from the ground
appeared to be dominated by the gravity of a massive
black hole.  However, prior to the HST observations,
more recent ground-based observational and theoretical
studies have failed to confirm this picture.

     Lauer, Faber, Lynds and co-investigators on the
WF/PC imaging team used the new images obtained with the
HST Planetary Camera to explore the central structure of
M87 much closer into its nucleus than is possible from
the ground.  The images show clearly that the stars in
M87 become densely concentrated towards the center,
forming a bright "cusp" of light at the heart of the
galaxy.

     The central density of stars in M87 is at least 300
times greater than expected for a normal giant
elliptical galaxy and over 1,000 times denser than the
distribution of stars in the neighborhood of the sun.
In fact, the ultimate central density of stars in M87
may be even higher, but its measurement is beyond the
resolving power of even HST.

     "The central structure of M87 is a striking
departure from what the normal core of a giant
elliptical galaxy would look like," said Lauer.  "It
strongly resembles a stellar cusp associated with a
black hole."  The cusp is visible as the steady increase
in brightness of M87 toward its center.  Theoretical
work suggests that such a cusp may form as a central
black hole grows and cause the center of the galaxy to
collapse outwards.

     Early in the life of M87 a "seed" black hole may
have formed in its nucleus from the merger of small
black holes created by the explosion of massive stars or
perhaps from the gravitational collapse of gas left over
from the formation of M87.  Once formed, the seed black
hole would grow by feeding on gas and stars that passed
by too closely.  As the mass of the black hole
increased, its gravity would begin to dominate an
increasingly larger volume of space.

     Stars, once freely orbiting in and out of the M87
core, would be gradually pulled towards the center and
then into orbits closely bound to the black hole.  The
whole core of the galaxy thus smoothly collapses inward,
and the density of stars near the very center becomes
extreme.  Some of these stars eventually may be consumed
by the black hole, fueling its growth further.  This
leads to an interesting paradox that one way to look for
a black hole is to search for a strong concentration of
starlight at the center of a galaxy.

     The mass of the black hole is estimated at 2.6
billion times that of the sun, based on comparing the
density of stars in the cusp to theoretical models
computed by Peter Young a decade ago.

     Lauer emphasizes, however, that the HST images
alone do not prove conclusively the black hole's
presence.  "It looks like a 'duck' but we haven't heard
it 'quack' yet," he observed.  Follow-on HST
spectroscopic observations are needed to measure the
velocity of stars orbiting within the nucleus.  High
velocities would be evidence of a black hole and would
provide astronomers with direct measurement of its mass.

     The search for super massive black holes in the
cores of galaxies is one of the primary missions of
NASA's Hubble Space Telescope.  By investigating both
active and quiescent galaxies, astronomers will have a
better idea of the conditions and events which lead to
the formation and growth of super-massive black holes.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                             January 16, 1992

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

Dr. Jon Holtzman
Lowell Observatory, Flagstaff, Ariz.

RELEASE:  92-9

        NASA's Hubble Space Telescope (HST) has provided intriguing new
clues to cataclysmic events in the history of the peculiar galaxy NGC 1275,
located approximately 200 million light-years from Earth.

        Astronomers have discovered about 50 bright objects at the center of
the galaxy which appear to be young massive globular star clusters.  This
discovery is surprising because most globular clusters are among the oldest
objects in the universe.  In fact, these clusters are used as a bench mark for
estimating the age of the universe.

        "Such objects have never before been seen," says Dr. Jon Holtzman, of
Lowell Observatory, Flagstaff, Ariz., who led the observing team that made
the finding.

        These results are being reported in a press conference at the 179th
meeting of the American Astronomical Society in Atlanta, Ga.  The paper is
being presented by Dr. Jon Holtzman; Dr. Sandra M. Faber, University of
California, Santa Cruz; Dr. Edward Shaya, University of Maryland; Dr. Tod R.
Lauer, National Optical Astronomy Observatories, Tucson: Dr. Edward Groth,
Institute for Advanced Studies, Princeton; Dr. Deidre Hunter, Lowell
Observatory and other members of the Wide Field/Planetary Camera
Instrument Definition Team.  Their results will be published in a paper to
appear in an upcoming issue of the Astronomical Journal.

        Holtzman's team did not expect to find young star clusters in NGC
1275 when it began observing with the HST Wide Field/Planetary Camera.
"We were looking for information to help us understand all the peculiarities
in the galaxy, but instead we discovered yet another strange feature," says
Holtzman.  This result may lead to a better understanding of how galaxies
evolve and interact through the process of collisions and mergers.

        Globular clusters are dense spherical collections of stars, containing
100,000 to 10 million stars packed in a region only about 100 light-years in
diameter.  More than 100 globular clusters orbit the Milky Way in a diffuse
swarm.  The brighter of these appear as "fuzzy" stars to the naked eye.

        Stars within these clusters are very old, believed to have formed early
in the history of the universe.  Surprisingly, the clusters in NGC 1275
appear to contain young, hot stars.  "Although young star clusters are
observed in other galaxies, none have been as massive and compact as those
seen in NGC 1275," says Holtzman.

        NGC 1275 has such a peculiar shape, some astronomers previously
have suspected that actually it may be two galaxies - a giant elliptical galaxy
and a smaller spiral galaxy -- passing through one another.  In fact, elliptical

galaxies in general may result from the merger of several spiral galaxies.
Holtzman suggests that the clusters may have formed as a result of just such
a merger or collision. The fact that elliptical galaxies can contain a hundred
times more globular clusters than spiral galaxies lends further support to
the notion that galaxy collisions also create new globular clusters.

        Other clues to the birth of globular clusters may come from the fact
that NGC 1275 lies at the heart of the Perseus cluster of galaxies, a rich
collection of more than 500 galaxies.  Because NGC 1275 is located at the
center of this cluster, the galaxy is surrounded by a luminous halo of hot gas,
which glows in X-rays.  Gravity pulls this superheated gas into the galaxy as a
"cooling flow," which produces filaments.  This cooling, condensing gas also
might produce newborn stars.  Holtzman and his colleagues plan to take
longer exposures with HST to see if there are many more fainter clusters.
He also plans to take pictures in ultraviolet light to help pin down the age of
the clusters better.

    Even with its defect, is the Hubble still better than ground-based
    telescopes?

It depends.  In the case of UV observations (which can't reach the ground
at all) definitely.  In the case of WF/PC normal-light images, if the image
is quite bright, it can be post-processed to compensate for a lot of the
spherical aberration and get quite good stuff.  If it is more faint, it is not
possible to get so much info out of the picture.

(My understanding...)

Burns

Article: 39455
From: [email protected]
Newsgroups: sci.space
Subject: HST Daily Report #554
Date: 21 Jan 92 21:06:11 GMT
Sender: [email protected]
Organization: The Internet
 
Subject: HST Daily Report #554
From:    ESIS
 
BULLETIN NUMBER:  17
DESCRIPTION: Daily report #554
FROM: STDESK       DATE: 21-JAN-1992 EXPIRES:  5-FEB-1992
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #554
 
PERIOD COVERED:  0800 EST 1/17/92 - 0800 EST 1/20/92
 
Daily Status Report as of 020/1300Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED
 
   1.1 Completed GHRS 2845 (1st Order Grating Spectral Lamp Test), no
       problems were reported.
 
   1.2 Completed six(6) iterations of WF/PC 3977 (Non-SV PC Flats - 2).
       Of the twenty-one(21) observations received, seventeen(17) were
       acceptable while the remaining four(4) were saturated.
 
   1.3 Completed seven(7) iterations of WF/PC 3978 (Non-SV WFC Flats -
       2). Of the seventy-three(73) observations received,
       fity-four(54) were good exposures, eighteen(18) were saturated,
       and one(1) was overexposed. Some prominent internal reflections
       were seen and a possible new faceplate contamination showed up;
       however, after comparisons with previous internal flats the new
       contamination was dismissed.
 
   1.4 Completed FOS 2717 (Probing the Voids). The observations
       received all looked good. Some observations showed strong
       Lyman-alpha (assumed geocoronal) plus various emissions at
       longer wavelengths.
 
   1.5 Uplinked the ephemerides twice, per MOC 2871.
 
   1.6 Completed FOC 3428 (f/96 High Voltage Turn-on). All observations
       received looked as expected.
 
   1.7 Completed WF/PC 3301 (PC Rapid Internal Monitor). The internal
       flats received were normal with no evidence of new contamination.
 
   1.8 Completed two(2) iterations of FOS 3923 (Cycle 1 Focus, X-Pitch
       and Y-Pitch). All observations received look like normal wave
       calibrations.
 
   1.9 Completed WF/PC 3230 (PC Point Spread Function and Focus
       Monitoring 2). The observation received showed the star directly
       on the Baum Spot in PC8.
 
   1.10 Completed WF/PC 3159 (Non-Proprietary "Snapshot" Survey - 2).
        The observation taken was on gyros, it contained a faint, trailed 
        fuzzy object in PC7. This is not the scheduled aperture.
 
   1.11 Complete WF/PC 2227 (Determination of Extragalactic Distance
        Scale). One observation executed in Coarse Track and the image
        is well exposed. The other observation executed in LOS;
        however, the image was well exposed and it's assumed the
        observation went well.
 
   1.12 Begin FOS 2424 (Quasar Absorption Line Survey).
 
2.0 FLIGHT OPERATIONS SUMMARY
 
   2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions :  5
                                        Successful :  5
                          Scheduled Reacquisitions :  8
                                        Successful :  8
                                    Losses of Lock :  0
 
   2.2 FHST Updates:
 
                                         Scheduled : 27
                                        Successful : 27
 
   2.3 Significant HSTARs: None.
 
   2.4 Operations Note: None.
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD
 
   3.1 Complete FOS 2424 (RD Quasar Absorption Line Survey).
 
   3.2 Complete WF/PC 3981 (PC Gravitational Lens Candidate 1208+101).
 
   3.3 Complete two(2) iterations of WF/PC 3159 (PC Non-Prop."Snapshot"
       Survey-2).
 
   3.4 Complete WF/PC 2227 (WFC Deter. of Extragalatic Distance Scale).
 
   3.5 Complete WF/PC 2600 (PC Cores of Early-type Galaxies).
 
   3.6 Complete HSP 1101 (UV2 Optical and U/V Obs. of Radio Pulsars).
 
   3.7 Complete WF/PC 3230 (PSF and Focus Monitoring 2).
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None.
 
   4.2 Significant Unresolved Anomalies: None.
 
5.1 SIGNIFICANT FORTHCOMING EVENT: Nothing at this time.
 
-END-
 
  Steven Fisk
  Internet: [email protected]
 
To: space   --andrew

Paula Cleggett-Haleim
Headquarters, Washington, D.C.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.


RELEASE:  92-22 (2/10/92)

        NASA's Hubble Space Telescope (HST) was used to study aurorae, not
on Earth but one-half billion miles away on the giant planet Jupiter. The
HST made observations of Jupiter over a 4-day period when ESA/NASA Ulysses
spacecraft swung by the giant planet.

        Ulysses used Jupiter's immense gravitational field to get a
"slingshot boost" out of the plane of the Solar System and onto a
trajectory toward the sun, where it will study the sun's polar regions
never before visited by a spacecraft.  Ulysses' closest approach to Jupiter
occurred on February 8th.

        While passing Jupiter, Ulysses made measurements of Jupiter's
powerful magnetic field and the flow of subatomic particles along magnetic
field lines.  Simultaneously, HST was looking at aurorae, one visual
manifestation of these electrical fireworks.  These joint observations will
provide a unique opportunity to combine ultraviolet images and spectra with
information on particles and fields.  This will lead to a better
understanding of what produces and maintains auroral activity.

        Despite the uncertainty as to whether the Jovian aurorae were
bright enough for HST to observe, astronomers say it was a worthwhile
experiment because of the unique opportunity to obtain auroral images and
spectra while a spacecraft was located inside Jupiter's magnetosphere.

        Several teams of astronomers used HST to observe auroral activity
at the north and south poles of Jupiter. High resolution images of
Jupiter's polar regions were taken with the Wide Field and Planetary Camera
and the European Space Agency's Faint Object Camera, while the Goddard High
Resolution Spectrograph studied the chemistry of auroral emissions.
Results from these observations will be analyzed in about a month.

        By studying the activity of Jupiter's aurorae, astronomers hope to
learn more about the dynamics of Jupiter's immense magnetic field, the
structure of the giant planet's upper atmosphere, the effects of aurora on
the chemistry of the polar regions on Jupiter and Jupiter's interaction
with the moon Io via a magnetic "flux tube."

        The shimmering colors and patterns of the aurora borealis (northern
lights) are a familiar sight to residents of northern United States and
Canada. Besides Earth, the gas-giant planets Jupiter, Uranus and Neptune
are known to have auroral activity.  Aurorae on Jupiter were first
discovered in 1979 by NASA's Voyager 1 spacecraft.  Aurorae have been
subsequently observed by NASA's International Ultraviolet Explorer (IUE),
as well as ground-based infrared telescopes.

        Hubble Space Telescope is ideally suited for studies of auroral
activity on Jupiter, as well as other planets, because Jupiter's aurorae
are most active at ultraviolet and infrared wavelengths.  The important UV
portion of the aurorae's spectrum cannot be observed through Earth's
absorbing atmosphere, hence studies cannot be done from telescopes located
on Earth's surface.

        The space telescope's ultraviolet sensitivity allowed astronomers
to filter out the glare of Jupiter and focus on the UV emissions from the
aurorae.  However, there is some uncertainty in the observations because
aurorae have never been directly imaged in this way and because the
strength of the auroral emissions varies over time.  This means that it's
possible that the aurora were too faint for HST to detect.

        Previous infrared ground based observations, in addition to
ultraviolet observations made with IUE and Voyager spacecraft, show that
Jupiter, like Earth, has auroral belts encircling the planet's north and
south pole.  On Jupiter these belts are about 1,000 miles wide.  HST may be
able to resolve details and structure as small as 100 miles across.

        Jovian aurorae radiate a trillion watts - a thousand times as much
energy as that which powers Earth's aurora.  How is this energy produced?
One possibility is that the processes are similar to those which produce
aurorae on Earth, but on a grand scale.

        Like Earth, Jupiter is enshrouded in a magnetic field, though it is
far larger and more powerful than Earth's. The solar wind, a steady stream
of electrons and protons from the sun, flows around this field.  Because
these particles are electrically charged, some become trapped and spiral
along field lines.  Aurorae are produced when these high energy particles
descend to Jupiter's magnetic poles and collide with gas molecules in the
Jovian atmosphere, making them fluoresce.

        Another possibility is that the aurorae are produced by sulfur from
Jupiter's volcanically active moon Io. Sulfur and oxygen ions, blasted off
of Io's surface, speed along a 5 million ampere river of electricity called
a "flux tube" which flows between Io and Jupiter's magnetic poles.  The
ions rain down into Jupiter's upper atmosphere at the foot of this flux
tube, when auroral activity may be intense.

        Auroral processes play an important role in the upper atmosphere of
Jupiter's polar region.  The steady cascade of particles may heat the
atmosphere and trigger chemical changes.

        The Hubble Space Telescope is managed and operated by the Goddard
Space Flight Center, Greenbelt, Md., for NASA's Office of Space Science and
Application.

        The Space Telescope Science Institute, Baltimore, Md., is operated
by the Association of Universities for Research in Astronomy, Inc. for
NASA, under contract with the Goddard Space Flight Center. The Hubble Space
Telescope is a project of international cooperation between NASA and the
European Space Agency.

Article: 511
From: [email protected] (Ron Baalke)
Newsgroups: sci.space.news
Subject: HST Monthly Status Report - February 1992
Date: 14 Mar 92 06:15:43 GMT
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
 
Forwarded from the Spacelink BBS
 
                     HUBBLE SPACE TELESCOPE
                      Monthly Status Report
                         February 1992
 
     One of the highlights of the month was the opportunity for the
HST to utilize its moving target capabilities to make observations of
Jupiter in conjunction with the NASA/ESA spacecraft, Ulysses, as
Ulysses swung by the giant planet.  Over a four-day period, from
February 6-9, five teams of HST observers implemented proposals using
the Wide Field/Planetary Camera (WF/PC), the Faint Object Camera (FOC)
and the Goddard High Resolution Spectrograph (GHRS) to observe auroral
activity at Jupiter's north and south poles.  The joint observation
provided the opportunity to combine ultraviolet images and spectra
from the HST with information on particles and fields from Ulysses and
perhaps contribute to a better understanding of what produces and
maintains auroral activity. 
 
     Another aspect of the HST program is swinging into full gear, and
that is the first servicing mission.  The latest NASA Shuttle Manifest
has the servicing mission (STS-61) scheduled for December 1993. 
Extensive coordination and planning activities are in progress and
include teams from Goddard Space Flight Center (GSFC), Johnson Space
Center (JSC) and Kennedy Space Center (KSC).  In recognition of the
complexity of the planned Extravehicular Activities (EVA), JSC has
agreed to move up the selections of two members of the four-person EVA
crew from the usual one year prior to launch to June of this year. 
 
     Currently, the observatory is performing normally with all
science instruments, except Side One of the GHRS, fully operational. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | In the middle of difficulty
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | lies opportunity  --
|_____|/  |_|/       |_____|/                     | Albert Einstein

Paula Cleggett-Haleim
Headquarters, Washington, D.C                  April 6, 1992

Randee Exler
Goddard Space Flight Center, Greenbelt, Md.


NOTE TO EDITORS:  N92-28

     The most exotic and powerful objects in the universe
will be the subject of a media briefing on Wednesday, April
8, 1992, at 1:00 p.m. EDT in the NASA auditorium, 400
Maryland Ave., S.W.

     New information about a potential, massive black hole
in our galactic backyard only 2.3 million light years away,
will be presented by Dr. Tod Lauer, a Hubble Space Telescope
scientist.  The result is based on analysis by Dr. Lauer of
the National Optical Astronomy Observatories, Tucson, Ariz.,
and the Wide Field/Planetary Camera imaging team.

     The discovery of a new class of "gamma ray quasars,"
which may emit huge energies in directed beams, will be
announced by Dr. Neil Gehrels, Project Scientist for the
Compton Gamma Ray Observatory, at NASA's Goddard Space
Flight Center, Greenbelt, Md.

     The significance of the new findings and their context
in the unfolding knowledge of the universe will be discussed
by a panel of distinguished astronomers, including Dr. Bruce
Margon, Professor of Astronomy and Chairman of the
Department of Astronomy, University of Washington, Seattle;
Dr. Daniel Weedman, Professor of Astronomy at Pennsylvania
State University, University Park; and Dr. Steve Maran,
Senior Staff Scientist at NASA's Goddard Space Flight
Center.

     This event will be carried on NASA Select Television
(Satcom F-2R, Transponder 13, 72 degrees west longitude,
frequency 3960.0 MHz, audio 6.8 MHz).  Questions will be
taken from reporters at Headquarters and at NASA centers.
 

Article: 713
From: [email protected] (Peter E. Yee)
Newsgroups: sci.space.news
Subject: NASA's Hubble finds new evidence for massive black holes (Forwarded)
Date: 8 Apr 92 18:08:34 GMT
Sender: [email protected]
Organization: NASA Ames Research Center, Moffett Field, CA
 
Paula Cleggett-Haleim
Headquarters, Washington, D.C.                  April 8, 1992
(Phone:  202/453-1547)
 
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)
 
Dr. Tod Lauer
National Optical Astronomy Observatories, Tuscon, Ariz.
(Phone:  602/325-9290)
 
Dr. Sandra Faber
University of California, Santa Cruz
(Phone:  408/459-2944)
 
RELEASE:  92-46
 
NASA'S HUBBLE FINDS NEW EVIDENCE FOR MASSIVE BLACK HOLES
  
	Astronomers report that they have found new evidence 
that a black hole, weighing 3 million times the mass of the 
Sun, exists at the center of the nearby elliptical galaxy 
M32, based on images obtained with NASA's Hubble Space 
Telescope (HST).  The images show that the stars in M32 
become extremely concentrated toward the nucleus.
 
	This central structure resembles the gravitational 
"signature" of a massive black hole.  The presence of a black 
hole in an ordinary galaxy like M32 may mean that inactive 
black holes are common to the centers of galaxies.  The new 
HST images show that M32 is an interesting "laboratory" for 
testing theories of the formation of massive black holes.
 
	This result is based on image analysis conducted by Dr. 
Tod R. Lauer of the National Optical Astronomy Observatories, 
Tuscon, Ariz., Dr. Sandra M. Faber of the University of 
California, Santa Cruz, and other members of the  HST Wide 
Field/Planetary Camera (WFPC) Imaging Team.
 
	M32 is quite small and compact as elliptical galaxies 
go, containing about 400 million stars within a diameter of 
only 1,000 light-years.  At a distance of 2.3 million light-
years, M32 (the 32nd object in a catalog of non-stellar 
objects compiled by French astronomer Charles Messier in 
1774) is one of the closest neighbors to the Milky Way galaxy.
 
	M32 is a satellite of the great spiral galaxy in 
Andromeda M31, which dominates the small group of galaxies of 
which the Milky Way is a member.  M31 can be seen with the 
naked eye as a spindle-shaped "cloud" the width of the full 
moon, and its small companion M32 can be seen with a small 
telescope.
 
	M32 has been among the best candidates for a galaxy 
with a massive central black hole.  This was first proposed 
in 1987 by Dr. John L. Tonry of the Massachusetts Institute 
of Technology, Cambridge, and independently by Dr. Alan 
Dressler of the Observatories of the Carnegie Institution, 
Wash., and by Dr. Douglas O. Richstone of the University of 
Michigan, Ann Arbor.
 
	Their observations, made with ground-based telescopes, 
showed an abrupt increase in the orbital velocities of stars 
towards the center of  M32.  This data led the astronomers to 
conclude that M32 must have a strong but unseen concentration 
of mass at its center.  A black hole at least several million 
times the mass of the Sun is the most likely type of object 
matching these characteristics.
 
	Ground-based images, however, do not have enough 
resolution to detect the effects of a massive black hole on 
the structure of M32.  The HST images analyzed by Lauer, 
Faber and co-investigators on the WFPC imaging team now show 
the nucleus of M32 in clear detail. 
 
	They find that the density of stars in the nucleus of 
M32 appears to increase steadily towards the center, with no 
sign of leveling off.  These results are very similar to the 
predictions for what a massive black hole should do to the 
central structure of a galaxy.
 
	"This is the densest stellar system known to 
astronomers," says Lauer.  "The density of stars at the 
center of M32 may be over 100 million times greater than the 
distribution of stars in the neighborhood of the Sun.  A 
visitor to a planet at the center of M32 would see a starry 
night sky so saturated with stars that their combined light 
would be brighter than 100 full moons.  The night would never 
get darker than mid-twilight on the Earth, and one could even 
read a newspaper by starlight."
 
	To date, HST has uncovered the gravitational signature 
of a black hole in one other galaxy, the giant elliptical 
galaxy called M87.  Both M32 and M87 have a distinctive 
central concentration of starlight called a "cusp."  These 
two galaxies are quite different, though, in that the black 
hole proposed for M32 is roughly 1,000 times smaller than the 
black hole that might exist at the heart of M87.
 
	Although M32 is about 20 times closer to the Earth than 
M87, its much smaller black hole means that the brightness 
cusp also is much smaller and is close to HST's resolution 
limits.  Unlike M87, M32 lacks any form of nuclear activity, 
which means that at present the black hole would not be 
accreting significant amounts of matter.  This result also 
raises the possibility that small inactive black holes are 
common to the centers of galaxies.
 
	Because the region dominated by the black hole is so 
small, Lauer and Faber also considered the possibility that 
no black hole is present.  Instead, the star density might 
level off just beyond the resolution limits of HST.  If this 
were the case for M32, it would force the researchers to 
conclude that the center of M32 is unstable and vulnerable to 
collapse.
 
	A black hole at the center of M32 would have the 
paradoxical effect of stabilizing the galaxy's nucleus.  
That's because the stars orbit so rapidly around the black 
hole, they move past each other too quickly to 
gravitationally capture each other or collide.  The black 
hole thus keeps the center of a galaxy "stirred up."
 
	In the absence of a black hole, however, the stars 
would move slowly enough to attract each other 
gravitationally.  Collisions between stars become much more 
frequent, and heavier slower moving stars sink to the center 
of the galaxy causing it to collapse.  
 
	The fate of the collapsing core is uncertain.  One 
possibility is that binary stars formed during the collapse 
would provide enough kinetic energy to halt the collapse by 
transferring momentum to single stars.  This would make the 
core rebound, like a rubber ball that has been squeezed and 
then relaxed. 
 
	An alternative possibility is that runaway merging of 
stars would occur during core collapse, leading to the 
formation of a black hole in any case.  If so, this would 
rule out alternative explanations that don't require a black 
hole.
 
	If the core is really unstable, the researchers would 
expect to find evidence of merged and captured stars called 
"blue stragglers'' (HST has in fact uncovered such stars at 
the core of a globular cluster, a much smaller aggregate of 
stars than M32).  The shape of the starlight distribution at 
the core would also be different from that which HST detects.
 
	The Hubble images instead show that the population of 
stars in the nucleus is the same as that further out in the 
galaxy, and that the shape of M32 remains constant into the 
center.  This means that a core collapse has not recently 
occurred.
 
	At the present time, astrophysical theories are not 
sophisticated enough to say whether or not M32 would have to 
evolve to make a central black hole, but do raise this as an 
intriguing possibility.  The new HST observations thus 
identify M32 as an interesting "laboratory" where astronomers 
can test theories of massive black hole formation.
 
	The search for super massive black holes in the cores 
of galaxies is one of the primary missions of NASA's Hubble 
Space Telescope.  By investigating both active and quiescent 
galaxies, astronomers will have a better idea of the 
conditions and events which lead to the formation and growth 
of super-massive black holes.
 
	The Space Telescope Science Institute is operated by 
the Association of Universities for Research in Astronomy, 
Inc., for NASA, under contract with the Goddard Space Flight 
Center, Greenbelt, Md.  The Hubble Space Telescope is a 
project of international cooperation between NASA and the 
European Space Agency.

                     HUBBLE SPACE TELESCOPE
                      MONTHLY STATUS REPORT
                           MARCH 1992

The Hubble Space Telescope continues to perform normal
operations, engineering activities, and science programs.
Scientific efficiency is currently at 30% and increasing toward
the mission goal of 35%.  Operational experience has led to
refinements in procedures and changes in both the ground and
flight software that contribute to the more efficient operations.

The Goddard High Resolution Spectrograph (GHRS) side 2 was
returned to routine scheduling of observations after a curtailed
operations period of about 8 months, during which the Project and
instrument Teams investigated an intermittent open circuit in the
electronics.

Extensive testing and analysis showed that the intermittent
failure was temperature sensitive and that maintaining the
temperature of the electronics at values above +5 degrees
Centigrade has the effect of closing the circuit.  A modification
to operational procedures has allowed the thermal environment
within the instrument to be controlled sufficiently to support
reliable operation of side 2.

Using this procedure, operations with side 2 have been run on an
experimental basis since November 1991 without experiencing a
communications failure.  Only routine operations with side 2 will
be scheduled while the Project investigates additional steps that
may be able to restore full operation to side 1.

The Wide Field Planetary Camera (WFPC) is experiencing some
residual contamination effects on the detectors.  When operated
at low temperatures, the instrument detectors experience a
contamination build-up.

The corrective procedure is to occasionally warm the detectors to
temperatures at which the substance evaporates.  In February,
after a routine clean-up procedure, it was found that the major
contaminant film had been removed but there remained a mottled
residual.

It is currently believed that the residual contamination most
likely resulted from an exceptionally heavy build-up of
contaminant material over a protracted period of time between
decontamination procedures (6 months).  Observations with the
WFPC are proceeding at their normal frequency while an indepth
assessment is made of the situation.  The residual contaminant is
expected to have only minor effects on the data.

HUBBLE SPACE TELESCOPE
MONTHLY STATUS REPORT
APRIL 1992


On April 24, 1992, the Hubble Space Telescope celebrated the
second anniversary of its launch to orbit aboard the Shuttle
Discovery.  The beginning of HST's third year of operations saw
announcements of a wealth of new astronomical discoveries,
increasingly successful science operations, progress towards
greater scientific efficiency and energetic planning for the 1993
Servicing Mission.

The anniversary was marked by the report of HST's discovery of a
potential black hole at the center of a nearby galaxy (M32), the
hottest known star (NGC2440), and images of Jupiter's aurora.

On April 7, an amateur astronomer in New Zealand detected the
rapid brightening of the dwarf nova OY Carinae.  Because only the
Faint Object Spectrograph (FOS) on HST is able to resolve both
the rapid variations of light during the outburst and provide the
important spectrographic data, a target of opportunity
observation was requested.  Science and Mission Operations
personnel were able to respond quickly and had the first
observation scheduled within five days of notification.
Approximately 13 observations of OY Car are being planned over
the next 2 months to monitor the changing phases of the event.
Other observing programs that were displaced by the target of
opportunity were rescheduled to a later date with minimal impact
to the programs.

The Solar Array Gain Augmentation (SAGA) II software was
installed successfully onboard the spacecraft on April 15.  SAGA
II is an upgrade to the software that currently is being used to
attenuate the jitter caused by the solar array panels.  The
upgrade is designed to compensate for the jitter mode at 0.6 Hz.
Preliminary results indicate significant improvement.  Flight
data will be collected over the next month to evaluate
performance further.

The first HST Servicing Mission (STS-61) is manifested for
December 1993 and the project is working enthusiastically towards
a November 1993 launch readiness.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                                 May 7, 1992
 
James Elliott
Goddard Space Flight Center, Greenbelt, Md.
 
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
 
RELEASE: 92-61
 
 
        NASA's Hubble Space Telescope has revealed an unusual and
fascinating new optical jet in the nucleus of the elliptical galaxy NGC 3862.
 
        "It appears that we are seeing a new class of phenomenon," says Dr.
Philippe Crane of the European Southern Observatory, who discovered the
jet in images sent back by the European Space Agency's (ESA) Faint Object
Camera on board HST.  "The jet-like feature was totally unexpected in this
galaxy.  This is typical of the kinds of discoveries that were expected from
HST."  Crane and ESA's Faint Object Camera Instrument Definition Team
made the observations.
 
        NGC 3862, also known as 3C264, is a bright radio source and x-ray
source.  It is the sixth brightest galaxy in a rich cluster of galaxies known as
 
Abell 1367, located at a distance of about 260 million light-years away in the
constellation Leo.  Previous observations of NGC 3862 taken in radio
wavelengths have revealed a jet-like structure that extends for a very long
distance.
 
        "Since the jet is only 0.6 arc seconds long (equivalent to the apparent
width of a dime located 2.5 miles away), it would have been very difficult to
see from a ground-based observatory," says Crane.  "The jet also is prominent
in ultraviolet light.  Both of these characteristics are especially well
exploited by the Faint Object Camera (FOC)."
 
        NGC 3862 was observed with the FOC in the high resolution (f/96)
mode, with two filters, on Jan. 25, 1992, .  One exposure, taken in yellow-
green light, was expected to reveal, outside the nucleus, the distribution of
the normal, old stellar population in the galaxy.  The second exposure, taken
in the near-ultraviolet light, was intended to reveal evidence for a young hot
stellar population in the nucleus.  To their surprise, the researchers found
the optical jet.
 
        Extra-galactic jets are not well understood.  They appear to transport
energy in a confined beam out from the active nucleus of the host galaxy.
Presumably, super-massive black holes are the powerhouses behind jets.
 
        Extra-galactic jets have been detected in radio wavelengths in many
active galaxies, but only a few have been seen in optical light.  Astronomers
do not yet understand why some jets are seen in visible light and others are
not.  They also would like to understand the connection between radio and
optical emissions.
 
        The NGC 3862 jet does not fit easily into the standard model of jets.
The new jet is markedly different in several ways from the optical jet seen
in M87 - a galaxy previously studied in detail by HST.  The NGC 3862 jet is
about 750 light-years long, compared to a length of 5,000 light-years for the
M87 jet.   The jet in M87 is brighter at redder wavelengths because it emits
reddish synchrotron radiation produced by high-speed electrons spiraling in
the magnetic field which confines the jet.  The NGC 3862 jet, however, is
much brighter in ultraviolet light, relative to visual light.
 
        "Further observations will be needed to clarify the nature of the
emission seen in this jet" says Crane.  This new type of jet suggests that
astronomers are seeing a new and unexpected phenomena in galactic nuclei.
 
        The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency.

Paula Cleggett-Haleim
NASA Headquarters, Washington, D.C.               June 2, 1992

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

RELEASE:  92-80



     NASA's Hubble Space Telescope (HST) has revealed a new
class of object in the universe -- a grouping of gigantic star
clusters produced by the collision of galaxies.  Images of the
core of the peculiar galaxy Arp 220 show that stars are
produced at a furious rate from the dust and gas supplied by
the interaction of two galaxies.

     The discovery was made by Dr. Edward Shaya and graduate
student Dan Dowling, University of Maryland, College Park, and
the Wide Field/Planetary Camera Team.

     Astronomers have never before seen a "starburst galaxy"
in such detail.  The core of Arp 220 promises to be a unique
laboratory for studying supernovas (the self-detonation of
massive stars) because they should explode frequently in
gigantic young clusters.

     Over time, the core of this galaxy should resemble a
string of firecrackers popping off.  This will provide
astronomers an unprecedented opportunity to study the late
evolution of massive stars, as well as possibly improve
techniques for measuring distances to galaxies, which use
supernovae as "standard candle" distance indicators.

     In the 1980s NASA's Infrared Astronomy Satellite
observatory showed that Arp 220 is the brightest of a dozen or
so "ultraluminous infra-red galaxies," which release 95
percent of their light in the infrared region of the spectrum.

     Ground-based telescopic images show a dust lane down the
center of Arp 220 which makes the galaxy appear double lobed.
Astronomers suspected that Arp 220's dark lane hid a massive
black hole which provided the energy for heating intervening
dust which re-radiates in infrared light.  These new
observations show that much of the energy is provided by giant
star clusters.  These star clusters will drive gas into the
accretion disk around the black hole.

     Astronomers doubted that an incredibly swift burst of
star formation could explain all of Arp 220's luminosity.  It
now seems that the dust is heated both by the nucleus and the
giant star clusters.

     The new Hubble observation seems to confirm a 1988 theory
by David Sanders (University of Hawaii), which predicted that
starburst activity is triggered in Arp 220 and other
ultraluminous infrared galaxies as a result of mergers of two
giant spiral galaxies.  Additionally, Joshua Barnes,
University of Hawaii, and Lars Hernquist, Lick Observatory,
University of Southern California, Santa Cruz, have calculated
that when two spiral galaxies merge much of the gas and dust
lose angular momentum and fall into the center.  This high gas
density would trigger a very high rate of star formation.

     HST reveals for the first time six luminous knots that
are super-bright star formation regions that lie within 2,000
light-years of the bright nucleus.  These clusters are much
brighter and ten times larger than any previously known star
cluster.  The HST observers speculate there may be even more
super-clusters embedded deeper in the dust lane.

     "We can now interpret previous microwave observations to
estimate the clusters' age to be greater than ten million
years," says Shaya.  "This means that they are no longer in
the starburst phase."  Frictional forces, however, should draw
these clusters toward the center of the galaxy where
gravitational tidal forces should tear them apart within 100
million years.  This limited age range adds further support
for the galaxy collision scenario.

     Since the clusters are young they must contain an
abundance of massive short-lived stars.  Shaya estimates that
these should explode as supernovae several times per year.

     The Space Telescope Science Institute is operated for
NASA by the Association of Universities for Research in
Astronomy, Inc., under contract with the Goddard Space Flight
Center, Greenbelt, Md.  The Hubble Space Telescope is a
project of international cooperation between NASA and the
European Space Agency.
 

                     HUBBLE SPACE TELESCOPE

                      MONTHLY STATUS REPORT
                            JUNE 1992



     Astronomers reported that NASA's Hubble Space Telescope had
detected a new class of object in the universe, gigantic and
violent star-forming clusters created by the collision of two
galaxies.  Images of the core of the galaxy ARP 220 show that
stars are produced at a furious rate from the dust and gas
supplied by the interaction of the two galaxies, producing what
is tantamount to a "supernova factory."

      Meanwhile, HST mission operations were nominal during this
reporting period, with operations having supported successfully
science observations and normal spacecraft activities without any
major problems.

     In addition to the regular general observer programs, three
programs from amateur astronomers were executed during the month.
The amateur astronomers visited the Space Telescope Science
Institute for assistance in conjunction with their observing and
receipt of associated data.

     The Amateur Astronomer Program on HST was announced in 1986
in recognition of the contributions of the estimated 300,000
amateur astronomers in the United States.  Amateur groups are
dedicated to activities such as monitoring variable stars,
mapping portions of the Moon and standing nightly watch to detect
new comets and supernovae events.  The amateur proposals for time
on HST are selected on a competitive basis similar to the
professional programs.

Article: 45053
From: [email protected] (John Roberts)
Newsgroups: sci.space
Subject: HST lecture notes
Date: 22 Jun 92 12:34:25 GMT
Sender: [email protected]
Organization: National Institute of Standards and Technology
 
"Results from the Hubble Space Telescope"
 
This lecture was held in the planetarium at the National Air and Space
Museum, and was given by Ed Weiler, the program scientist for HST.
This lecture was one of a five-part lecture series entitled "Exploring
New Worlds", which was sponsored, interestingly enough, by Hughes
Danbury Optical Systems. (Dr. Weiler emphasized that they had *not*
requested a lecture on HST, but the organizers had felt the topic was
current and relevant, so they had included this lecture. Since several
Hughes Danbury people were present, I was interested in what Dr. Weiler 
would have to say about the mirror flaw.) 
 
The main part of the lecture was on the recent discoveries by HST,
which I won't repeat because they've been covered in the excellent
postings by Ron Baalke, Peter Yee, and others. There were several
side-by-side shots of some notable objects, comparing the best
ground-based views and the HST images - even without correction, the
HST images were much more detailed. Also shown were HST images of
Jupiter and Saturn compared with Voyager images - the HST images were
not much worse than the Voyager images, and far better than
ground-based images. Dr. Weiler pointed out that HST had the advantage
of being able to take these images just about any time, instead of
being limited to a brief flyby, so that transient phenomena such as
the Wilbur Spot could be studied, and long-range weather patterns
could be documented. 
 
The final part of the lecture was on the upcoming repair mission. This
mission is important because although HST can now get full resolution
with bright objects, or look at fainter objects with decreased
resolution, it's highly desirable to get full resolution of fainter
objects in order to study more distant galaxies and quasars, get a
more accurate measurement of the Hubble Constant, and so on. The
repair mission should at the very least allow astronomers to get full
resolution of objects an order of magnitude fainter. The service
contract for the repair mission specifies 90 percent correction of the
optical flaw, but all the people involved are working very hard at
doing the job as well as they can - they're shooting for 100 percent
correction, and there's considerable optimism toward greatly exceeding
the 90% specification. 
 
After the lecture, there was a question and answer session. I wanted
to ask whether there's any ongoing effort to make as much use of the
high speed photometer as possible before it's removed, but didn't get
a chance. Some of the other questions: 
 
Q: Why did you launch HST, if you knew about the flaw in the mirror?
A: If we'd known about the flaw, there's no way we would have launched and
   subjected ourselves to the congressional inquiry.
 
Q: Why didn't you test HST before launching?
A: HST was tested, and the testing was adequate to detect the error. (In
   fact, the testing *did* detect the error.) The problem was the result of
   two human errors. First, the reflective null corrector that was used in
   making and testing the telescope was calibrated incorrectly, because
   a paint chip was knocked off the end cap of the calibration rod. Second,
   when testing detected the error, the results of those tests were ignored.
   (The null corrector used in those tests was considered less accurate than
   the null corrector that had been calibrated incorrectly.)
 
Q: Why not just stick with those high-resolution imaging tricks being 
   developed for ground-based telescopes.
A: One factor to consider is that the ground-based techniques [I didn't
   record which ones he was talking about] can only produce a field of view
   20 arc seconds across. HST can get high-resolution images in a field
   180 arc seconds across, and when fixed, it will be able to get much 
   fainter objects. Also, it can image in the ultraviolet, which is blocked
   by the Earth's atmosphere.
 
Q: How much will the repairs cost, compared to normal operation?
A: COSTAR costs about $40 million, the optical correction to WF/PC II
   about $10 million, the solar arrays are to be replaced (the European
   supplier has figured out the problem that causes the wobble, and is
   producing the replacement arrays), so total incremental cost of the
   repair is about $50-60 million. The cost of the HST program is about
   $1.6 billion plus operations costs, for a total of about $2 billion.
 
Q: How long will HST last? Will they just abandon it or return it to Earth
   after 15 years?
A: With regular maintenance every three years, HST ought to last well beyond
   the design goal of 15 years.
 
[Note: my reconstruction of the lecture is not guaranteed 100% accurate.]
 
John Roberts
[email protected]


Article: 45041
From: [email protected] (John Roberts)
Newsgroups: sci.space
Subject: Re: HST
Date: 22 Jun 92 03:58:12 GMT
Sender: [email protected]
Organization: National Institute of Standards and Technology
  
-From: [email protected] (Pat)
-Subject: Re: Moon/Mars funding
-Date: 21 Jun 92 18:16:37 GMT
-Organization: UDSI
 
-In article <[email protected]>
[email protected] (John Roberts) writes: 
->
->is to NASA's advantage to head that way. (I'm not including projects like
->HST, which *have* to be big to get the best results. But Galileo, for
 
-I don't think HST needed to be big,  it could have achieved numerous science 
-goasl  as smaller packages..  from what i saw the  photometer and FOC could
-have been separated and the spectrograph could have been separated onto
-devices with much smaller mirrors.  more science return, less risk, faster
-launch.......
 
-HST was big, cuz that garnered attention, not because it was the best design.
 
You didn't include quite enough information for me to evaluate your
views. The most important question: do you understand the concept of
diffraction limits of resolution for receivers of electromagnetic
energy? I somehow cleverly managed to erase my copy of the formula
(could somebody please post it? I don't think it's in the frequently
asked questions file yet), but basically, it's a function of aperture
and wavelength. The shorter the wavelength, and the larger the
aperture, the greater the detail you can resolve. The HST instruments
WF/PC and FOC are designed to give resolution pretty close to the
diffraction limit (and do even now, for bright objects), so it's
important to get the aperture as large and the optics as precise as
possible. In principle, one could use smaller reflectors plus optical
interferometry, but that's hardly out of its infancy on Earth, and I'm
not aware of any *current* optical interferometric *imagers*, except
for systems such as the Multiple Mirror Telescope, which aren't quite
the same thing. 
 
I don't know the resolution of the other instruments (anybody have
those?), so it's possible they could get by with smaller mirrors.
(Judging by the name of the Goddard High Resolution Spectrograph, it
might indeed need the large mirror.) However, there are at least four
factors that could be used to argue against separating them out: 

 1) Most astronomical instruments benefit from getting as much light as
    possible. (The big traditional scopes on Earth are essentially "light
    buckets", with apertures so large that the turbulence of the atmosphere
    is a far stronger determinant of resolution than is the diffraction
    limit, just in order to gather a lot of light for spectrometers, photon 
    counters, etc.) So even if some of the instruments don't need a large
    mirror for resolution, they still need a large mirror for light gathering.

 2) For many of the experiments, proper pointing is crucial. So if you split
    up the instruments, each spacecraft still has to have the reaction
    control system, guide star sensors, computer control system, etc. And
    managing HST is a very difficult task, which takes a lot of manpower on
    the ground. Having to control all of these spacecraft just adds to
    the workload.

 3) It can be extremely valuable to have coordinated observations - several
    instruments all looking at the same object. This is automatic with HST;
    coordination of multiple spacecraft would be a difficult task, especially
    since they would have to be placed pretty far apart if they share an orbit.

 4) The HST instruments are designed to be periodically serviced, and
    occasionally replaced with more advanced designs. (WF/PC II was being
    constructed even before HST was launched.) One Shuttle mission
    every few years to service HST is plausible, but one mission every few
    years for each of several spacecraft or one mission to service several
    spacecraft would be far more difficult to accomplish. You could just
    launch whole new spacecraft each time, but if they are expected to
    have capabilities comparable to the corresponding components of HST,
    it's not clear that there would be a net cost savings.
 
As I said in the previous post, I think some missions would have been
better if split up into multiple smaller missions, but I think there
is considerable justification for putting most or all of the HST
components on a single spacecraft, and for making the optical portion
of that spacecraft as large as possible. If you have specific
technical points to make that indicate the HST instruments should have
been split up, I would appreciate hearing them. 
 
In the meantime, I'll try to find my notes from the HST lecture I
attended a few weeks ago, and post the relevant portions. 
 
John Roberts
[email protected]

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                   June 29, 1992

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

RELEASE:  92-97


        Using NASA's Hubble Space Telescope (HST), an international team of
astronomers has taken a major first step in redetermining the expansion rate of
the universe.  This rate, known as the Hubble Constant, is one of two critical
numbers needed for making a precise determination of the size and age of the
universe.

        These results are being reported by Drs. F. Duccio Macchetto, Nino
Panagia and Abhijit Saha of the Space Telescope Science Institute, Baltimore
Md.; Allan Sandage of the Carnegie Institute of Washington and Gustav Tammann
of the University of Basel, Switzerland, at the international workshop "Science
With The Hubble Space Telescope," being held in Sardinia, Italy, June 29
through July 9.

        Using HST's Wide Field and Planetary Camera (WF/PC) in the wide field
mode, the team found 27 Cepheid variable stars in a faint spiral galaxy.  The
galaxy, called IC 4182, is located 16-million light years away in the northern
sky constellation Canes Venatici.

        Cepheid variable stars rhythmically change in brightness over intervals
of days -- the prototype is the fourth brightest star in the constellation
Cepheus. Early in this century astronomers found a direct link between a
Cepheid's pulsation rate and its intrinsic brightness.

        Once a star's true brightness is known, its distance is a relatively
straight-forward calculation because the intensity of light drops off at a
predictable rate.  Though Cepheids are rare, they are very reliable "standard
candles" for estimating intergalactic distances.  Only once before have
Cepheids been found in a more distant galaxy (M101, located 23 million
light-years away).

        "The few Cepheids found in M101 with ground-based telescopes were
unusually bright and required an enormous effort over many years," says
Macchetto. "Only the Hubble Space Telescope can make these types of
observations.  Cepheids are too faint and the resolution too poor, as seen from
ground-based telescopes, to separate the images in such a crowded region of a
distant galaxy."

        The galaxy IC 4182 was chosen as a target for a Cepheid search because
it is the site of a type Ia supernova explosion which occurred in 1937.  Type
Ia supernovae are thermonuclear explosions that may occur in systems containing
a pair of white dwarf stars.

        Models predict that all supernovae of this type should reach
approximately the same peak brightness -- as if all light bulbs manufactured in
the world were exactly 60 watts.

        Like the Cepheids, Ia supernova can be reliable standard candles, but
only if astronomers accurately know their true intrinsic brightness.  Type Ia
supernovae are more useful than Cepheids because they are much brighter and can
be seen at far greater distances.  These supernova are the next "rung" in a
"ladder" of techniques for estimating cosmological distances.

        The problem is that astronomers have been uncertain about the absolute
brightness these supernovae reach at maximum.  By accurately determining the
distance to IC 4182 using Cepheids, astronomers can calibrate the intrinsic
brightness of the 1937 supernova.  They essentially now can "link together" two
rungs in the cosmological distance ladder.

        Since type Ia supernovae can be seen 1,000 times farther than the
Cepheids, they can be used to determine large cosmological distances
accurately.  This measurement is a critical step in refining the true value of
the Hubble Constant, first developed by the American astronomer Edwin Hubble in
1929.

        Hubble found that the farther a galaxy is, the faster it is receding
away from us.  This "uniform expansion" effect is strong evidence that the
universe began in an event called the Big Bang and has been expanding ever
since.

        The Hubble Constant is an estimate of the rate at which the universe is
expanding and is expressed in kilometers per second per megaparsec (3.26
million light years).  The Hubble Constant is one of two critical numbers
needed to determine the intrinsic curviture of space and the fate of the
expansion.

        The other number needed is the mean density matter in the universe or
an independent verification of the age of the universe.  Previous estimates for
the Hubble Constant vary by a factor of two (50 vs. 100 kilometers per second
per megaparsec).

        Using the absolute calibration of this single type of supernovain IC
4182, the researchers yield a range for the Hubble Constant of between 30 and
60 km/sec/Mpc.  The most probable value is in the middle of this range,
yielding a value for the Hubble Constant of 45 km/sec/Mpc, which implies a
minimum age for the universe of 15 billion years.

        The astronomers plan to narrow this range for Hubble Constant by
detecting Cepheid variable stars in other galaxies that have had recent type Ia
supernovae as well.  These observations will be made next year with HST.

        When a second generation WF/PC is installed in HST during a Space
Shuttle servicing mission in 1993, the astronomers expect to detect Cepheid
Variables out to the Virgo cluster of galaxies, estimated to be 60 million
light-years away.  The ultimate goal is to use HST to refine the scale of the
universe to within 10 percent.

        The Space Telescope Science Institute is operated by the Association of
Universities for Research in Astronomy, Inc., for NASA, under contract with the
Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a
project of international cooperation between NASA and the European Space
Agency.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                                June 29, 1992

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

RELEASE:  92-98


        A serendipitous survey of the heavens with NASA's Hubble Space
Telescope (HST) is uncovering remote and unusual galaxies never before resolved
by optical telescopes on Earth.

        HST reveals an unusual variety of shape and structure in these distant
galaxies, which previously appeared as fuzzy blobs in ground-based sky surveys.
These early results may lead to a much clearer understanding of the formation
and evolution of galaxies.

        These results are being reported by Dr. Richard Griffiths of the Space
Telescope Science Institute, Baltimore, Md., at the international workshop,
Science with the Hubble Space Telescope being held in Sardinia, Italy, June 29
through July 9.

        Some of the remote galaxies, estimated to be between 5 and 20 billion
light-years away, do not have the familiar spiral and elliptical shapes
characteristic of galaxies in the nearby universe, according to Griffiths.

        One cosmological model is that galaxies in the early universe interact
dynamically and grow bigger by cannibalizing smaller regions of star formation.
If so, the objects resolved by HST may be "building blocks" for today's large
galaxies.

        "We have seen several examples of what appear to be interacting or
merging galaxies," says Griffiths, the principal investigator on this key,
long- term HST project.

        The HST's Medium-Deep "Parallel'' survey is carried out using HST's
Wide Field Camera to take pictures in a random field while a "primary''
instrument, such as a spectrograph, is performing an observation on a
preselected target about one-sixth the moon's diameter away.

        "By operating two instruments simultaneously, the overall efficiency of
the telescope is greatly improved," says Griffiths. "During the course of the
Survey, several thousand images will be recorded."

        Pictures are taken in multiple colors -- including the ultraviolet,
visual and infrared -- and searched for the unknown and unexpected.

        Mission planners at the Space Telescope Science Institute developed the
techniques necessary to schedule these observations without affecting the HST's
primary science projects.  The survey is led by Johns Hopkins University and
STScI in collaboration with a dozen astronomers in the USA and the United
Kingdom.

        The Space Telescope Science Institute is operated by the Association of
Universities for Research in Astronomy, Inc. for NASA, under contract with the
Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a
project of international cooperation between NASA and the European Space
Agency.

         This past weekend my two sons were watching some sort of race
         on TV in which different classes of pick up trucks were
         bouncing around a muddy track.  I was reading the paper and
         not really following what was going on.  At one point they
         broke to a segment about a near by observatory which housed a
         large refracting telescope.  At this point I started to
         watch.  It was mentioned that the instrument was used by
         Edwin Hubble, "the inventor of the Hubble space telescope".

         Fran

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                     July 15, 1992
(Phone:  202/453-1547)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)


RELEASE:  92-111

HUBBLE CLOSES IN ON THE CAUSE OF SOLAR FLARES


	A fleeting event on a tiny red star could help scientists explain the
cause of flares that erupt on the sun and have pronounced effects on the
Earth, reported Hubble Space Telescope (HST) astronomers from NASA's
Goddard Space Flight Center, Greenbelt, Md.

	"This is a case where observing another star can help us understand
our own sun," said Dr. Bruce E. Woodgate, who led the science team making
the new finding.  The stellar flare event was monitored by the Goddard High
Resolution Spectrograph on HST on Sept. 3, 1991.

	The Hubble observers found evidence of a powerful beam of
downward-streaming protons (nuclear particles with a positive electrical
charge) at the onset of a stellar flare.

	The telltale evidence of the proton beams was a brief but striking
increase in the intensity of ultraviolet radiation at wavelengths slightly
longer than the characteristic wavelength of "Lyman-alpha," the principal
radiation emission of hydrogen atoms.  This radiation was caused by protons
moving downward at high speed in the atmosphere of the observed star
(called AU Microscopium).

	"As the protons move downward, they collide with hydrogen atoms
and rob them of their electrons," Woodgate explained.  "That makes the
rapidly descending protons become hydrogen atoms."

	"The atoms emit their characteristic light of Lyman-alpha.  But because
the atoms are moving downward on the star and therefore, are moving away
from us as we look at the star, the light is shifted to longer wavelengths by
the Doppler effect," said Woodgate.

	To recognize the observed effect as corresponding to the predicted
proton beams, the Hubble observers required that the phenomena must
occur at the onset of a stellar flare, in the so-called impulsive phase of the
flare and that it be of very short duration.  In fact, the increase of light
that
they found near the start of the flare on star AU Microscopium lasted only 3
seconds.

	No other such brightening was observed at any other time during two
hours of monitoring with the Hubble telescope, leading the scientists to
estimate that there is only one chance in 40,000 that they had recorded a
coincidental effect not related to the stellar flare.  Nevertheless, the
scientists are planning further observations with HST to verify their finding.

	The occurrence of this phenomenon in flares on the sun was
predicted in 1976 by American astronomers Frank Q. Orrall and Jack B.
Zirker.  But instruments on sun-watching satellites have not had the
necessary capabilities to detect it.

	"We tried to find proton beams in solar eruptions using the Solar Max
satellite," explained Dr. Steve Maran, one of the authors contributing to this
research, "but the spectrograph could not obtain measurements at a
sufficiently rapid rate."  The Solar Maximum spacecraft was launched on Feb.
14, 1980, and reentered the Earth's atmosphere on Dec. 2, 1989.

	"We've been studying this for 15 years to find the first possible
confirmation of the theory," Woodgate said.  Woodgate and associates Drs.
Kenneth G. Carpenter and Stephen P. Maran collaborated with Drs. Richard
D. Robinson and Steven N. Shore, of Computer Sciences Corp., all who work
at Goddard.

	The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency.

- end -

EDITORS NOTE:  A 35-second video showing animation of the stellar flare is
available to the news media by calling NASA's Broadcast and Imaging Branch
on 202/453-8375.

From:	DECWRL::"[email protected]" 30-JUL-1992 
        13:18:10.72
To:	[email protected]
CC:	
Subj:	HST Emergency - 07/30/92

                           HUBBLE SPACE TELESCOPE
                            Spacecraft Emergency
                               July 30, 1992

     On July 30 at 0440Z, the HST POCC (Payload Operations Control
Center) declared a spacecraft emergency due to a bad ephemeris load on
the spacecraft causing it to not point at TDRS.  The spacecraft is in
inertial hold and its health is not threatened though all science
instruments have been shut down until the situation has been
rectified.  Two DSN (Deep Space Network) tracking passes were
requested, one each over DSS-46 (Canberra 26 meter antenna) and DSS-16
(Goldstone 26 meter antenna).  At the end of the DSS-46 track, the HST
project reported that commands to the spacecraft reconfigured it to
TDRS mode.  The project also reports the DSS-16 pass is still required
and will probably be the last support required of the DSN. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Most of the things you 
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/  |_|/       |_____|/                     | happen.

Article: 1594
From: [email protected] (Ron Baalke)
Newsgroups: sci.space.news
Subject: HST Update - 07/31/92
Date: 31 Jul 92 23:34:50 GMT
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
 
                             HUBBLE SPACE TELESCOPE
                              Spacecraft Emergency
                                 July 31, 1992
 
     The Hubble Space Telescope spacecraft emergency continues. 
DSS-16 and DSS-17 (Deep Space Network's antennas in Goldstone,
California) provided support for the emergency.  Goddard Space Flight
Center reported a bad ephemeris load caused the bright object detector
to take the spacecraft to safe mode.  Yesterday, both TDRS and DSS-17
was unable to acquire a downlink from Hubble.  As of this morning, the
Hubble emergency is still on, though Goddard reports nominal support
via TDRS. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Most of the things you 
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | worry about will never
|_____|/  |_|/       |_____|/                     | happen.

Article: 25291
From: [email protected]
Newsgroups: sci.space,sci.astro
Subject: Re: Hubble used for spying? + other neat info
Date: 5 Aug 92 05:42:52 GMT
Organization: University of South Australia
 
In article <[email protected]>
[email protected] writes:
 
>In article <[email protected]> 
>[email protected] (E.J. du Toit) writes:
>
>>Can the Hubble telescope be rotated to view the earth's surface and what 
>>could be seen (resolution)?
>
>No.  The Earth is too bright, even at night.  Pointing Hubble at Earth
>(or even the moon) would burn out (or seriously endanger) the Faint
>Object Camera.
 
I attended an excellent lecture by Dr. Eric Chaison of the Space
Telescope Science Institute that was given in Cleveland, Ohio in
November last year. This same question was asked by the audience and
the answer is yes, you can use Hubble to view Earth's surface. In
fact, it is routinely done for calibrating the instruments.
Fortunately for the scientists, they made the minimum exposure time
long enough such that all you see is a big blur, otherwise the U.S.
military and C.I.A. would want to start using it! There was also a
mention of the backup mirror made by Kodak (which was not flawed). It
is currently sealed inside a big box and no-one is allowed to look
inside the box. Makes you wonder if the Kodak mirror is still on
Earth or up there spying on Saddam Hussein! 
 
I wrote down details of the rest of the talk on my little dinner card.
Here's what I can make out of it. The solar panels are apparently
oscillating up to 28 cm peak to peak for about 3 seconds after passing
through the day/night terminator with up to 1 m oscillation on one
solar panel which was supposed to have been observed by U.S. spy sats
(KH-11 or KH-12). The cause is due to the use of stainless steel on
the deployment rods. Someone forgot to take into account the
coefficient of expansion of stainless steel as Hubble passed from day
to night and vice versa. The scientists are worried that stress may
break the rods. If that happens, you can kiss Hubble goodbye because
it would loose attitude control and half its power. However, the
engineers say that this won't happen and that Hubble will survive
until the repair mission in December 1993. 
 
There is also a theory that the oscillations may have contributed to
the failure of the 2 gyros, since they are being worked harder to
compensate for the oscillations. The real cause of the gyros failing
has been determined as using integrated circuits that wern't made
radiation hard enough for the Van Allen belts and South Atlantic
Anomaly. The real bummer is that apparantly these chips are also used
on U.S. spy sats where they had failed before Hubble was launched.
This information was not passed onto NASA because of the secrecy
behind the spysats. There is also another gyro which is drawing a high
current but is still usable.  Hubble has 6 gyros and requires 3 for
science operations. If 2 more gyros fail Hubble will be put into a
safe non-science mode to await repair (a set of very reliable, but
coarse accuracy gyros are used). 
 
Another fault is in the Wide Field Planetary Camera (WFPC).
Apparrantly, lanolin was used on the rivets which outgassed. The
gasses settled onto the mirror and lanolin is opaque to ultraviolet!
The camera can still see in visible though. The main mirror is 2
microns flatter at the edge which is causing all the spherical
abberation. To overcome this, 85% of the halo in each image of a star
is thrown away to obtain high resolution. This means that Hubble can
see bright objects really clearly, its the faint ones that Hubble has
trouble seeing. 
 
There was also a lot discussed on the upcoming repair mission. The
first thing that has to be done is to replace the solar panels with
ones that don't vibrate. The next job is to replace the broken gyros
with two new units (there are 2 gyros per unit). After that, a new and
improved WFPC will be put in. The last thing to be put in is the
COSTAR. The COSTAR will replace the High Speed Photometer and will
deploy 5 pairs of 5 cent size mirrors before the other 3 instruments
(the WFPC has its own corrective optics). This will clear up 90% of
the problem. If the corrective mirrors are more than 3% out of
alignment the images will be as bad as they were before, so great
accuracy is required. Unfortunately, the COSTAR was designed so that
it could replace only the HSP. If one of the other instruments were to
fail, the astronauts could end up pulling a perfectly good HSP to
correct for a failed instrument! The Goddard High Resolution
Spectrograph is having power supply problems and that's another job
for the astronauts to fix! What is worrying the scientists is that the
astronauts won't have enough time to fix all of Hubbles problems. Only
four 6 hour EVA's are planned, with one EVA left as reserve! 
 
Other info on Hubble was its pointing accuracies, resolutions, and
observation times. The WFPC has 0.1 arcseconds resolution, the Faint
Object Camera has 0.03 microns. Pointing accuracy is 0.007 arcseconds
and the jitter due to the solar panels is approximately 0.1 arcseconds
and has to be compensated for by the gyros. Hubble also only can get
30 minutes of data in each 96 minute orbit since the rest of the time
is spent looking at Earth. 
 
All the above information was given at the talk and in speaking with
Dr. Chaisson after his talk. I hope I have not made any errors, but
this was over 8 months ago and I have only my little card to go by and
my sometimes not so perfect memory. 
-- 
Steven S. Pietrobon,  Australian Space Centre for Signal Processing
Signal Processing Research Institute, University of South Australia
The Levels, SA 5095, Australia.      [email protected]

re .270
    
>What is worrying the scientists is that the astronauts won't have enough time
>to fix all of Hubbles problems. Only four 6 hour EVA's are planned, with one
>EVA left as reserve!
    
    Perhaps an EDO mission could be used that would allow more EVAs? Or is
    that already the plan?

Manifest shows a 9 day mission with Atlantis (not an EDO).


The cargo bay is probably pretty full up with replacement parts, workshop,
etc.    I've seen two of the modules -- they're not small...   [I don't know
how big the EDO pallet is, however]


- dave

"From our home on the Earth, we look out into the distances and strive
to imagine the sort of world into which we are born.  Today we have
reached far out into space.  Our immediate neighborhood we know rather
intimately.  But with increasing distance our knowledge fades rapidly,
until at the last dim horizon we search among ghostly errors of
observations for landmarks that are scarcely more substantial.  The
search will continue.  The urge is older than history.  It is not
satisfied and it will not be suppressed. "
                        -- Edwin P. Hubble
                           (1889 - 1953)


HUBBLE SPACE TELESCOPE

In April 1990, Space Shuttle Discovery launched Hubble Space Telescope
-- perhaps the most ambitious scientific mission NASA has ever
undertaken.

Then, in June 1990, came the disappointing news of spherical
aberration in the HST primary mirror.  Many concluded prematurely that
the project had no future.

But now, after 18 months in orbit, HST is in routine operation and has
surprised its early critics by producing results at the forefront of
science.  Regular Shuttle servicing missions should permit the
telescope to achieve its original scientific goals over a planned
15-year observing lifetime.



UPDATE:  18 months in Orbit


THE FIRST 18 MONTHS

More than 1,900 observations of nearly 900 astronomical objects have
already been carried out by HST.  Observations began with imaging but
now include spectroscopy.  Scientists obtain information on the
temperature, composition, and motion of an object by analyzing the
spectrum of radiation emitted or absorbed by the object.  Observing
time is in great demand by astronomers worldwide.


I THOUGHT IT WAS BROKEN.

Pluto and its close satellite Charon, barely distinguishable as
separate bodies in a ground-based image are clearly separated in the
HST image.  Because Charon is half the size of Pluto, this system is
often called the "double planet."

Ring of gas around Supernova 1987A, as shown in a HST image, was
ejected many thousands of years prior to the blast.  In combination
with spectroscopy by NASA's International Ultraviolet Explorer
satellite, HST measurements of the ring's angular size yielded the
distance to the supernova.

Q:  What's the real story with HST? I thought it was broken.
A:  Hubble Space Telescope is the most capable optical telescope
available to astronomers today, despite the mirror problem.  It is
producing images and spectral observations that place HST programs at
the forefront of astronomy.

Q:  How is that possible?
A:  First of all, HST has greater clarity of view than any
ground-based optical observatory, both because of the substantial
light-gathering power of its 94-inch mirror and because of its
location in space above the distorting effects of Earth's atmosphere.
In addition, its location in space permits HST to observe ultraviolet
radiation that does not penetrate the atmosphere.

Q:  But what about the mirror problem?
A:  Because the mirror was so perfectly polished -- albeit to a
slightly incorrect shape -- the effects of the spherical aberration
can often be removed by computer processing.  Many processed images
reveal breathtaking detail never before seen from the ground.

Q:  What is the long-range future of Hubble Space Telescope?
A:  Bright.  Through Shuttle servicing missions, which were planned
from the beginning, we can achieve the capabilities intended for HST
early in the observatory's 15-year mission lifetime.  Over this
period, HST should be able to achieve its original scientific
objectives.

IN FACT, Hubble Space Telescope is the most powerful optical telescope
in the world today:  it offers unmatched ability to image fine detail
and to study ultraviolet radiation from astronomical objects.


ACHIEVEMENTS AMID CHALLENGES

Star Regeneration in 47 Tucanae
In the cores of old globular clusters like 47 Tucanae, thousands of
stars are crowded into a region less than one light-year across.
Could these ancient stars ever be regenerated by stellar mergers or
collisions? Ground-based telescopes have not been able to answer this
question; their images of such cluster cores are smeared out by
atmospheric turbulence.  But in the core of 47 Tucanae, HST's clear
view from space has revealed dozens of hot blue luminous stars
radiating away energy so rapidly that they cannot have survived since
the birth of the cluster itself.  These observations provide the first
convincing evidence of recent star regeneration in old clusters.

HST images of Saturn, recorded at quarterly intervals of the planet's
10-hour rotation period, show successive quadrants of the surface.
Hundreds of such images, computer processed to bring out fine detail,
were assembled into a 1991 film to illustrate the progress of a giant
storm across Saturn's turbulent atmosphere.

Q:  Have you had to meet other challenges, besides the mirror?
A:  Yes -- which is not surprising for a complex system with 400,000
different parts.  For example, the solar-power arrays supplied by the
European Space Agency make HST "jitter"' or shake, every time the
spacecraft orbits into and out of daylight.  But we have fixed most of
the problem by writing special computer programs for the HST pointing
system.

Q:  Is HST especially vulnerable to malfunctions?
A:  Quite the opposite.  HST, as well as being serviceable in space,
was designed to provide high redundancy and extensive backup
capabilities.  For example, two gyroscopes used for pointing control
have stopped functioning; but we've activated two spare gyros to
continue normal operation, and another space is still available.
Overall, very few of HST's reserve capabilities have been needed so
far.

Q:  So the capability for forefront science remains high?
A:  Yes.  Consider scientific papers presented at the January 1992
meeting of the American Astronomical Society.  Of the papers reporting
space science observations -- which represented 25 percent of all the
observational papers -- one out of four described HST results.  And
demand for observing time remains strong.  In 1991, some 450
scientific groups submitted new proposals to use the telescope.

A storm was revealed in September 1990
by ground-based observations.  The HST observing schedule was quickly
modified to permit HST to track the disturbance, which by November had
spread to cover most of the plant.  White areas detected in images of
the storm are believed to be immense clouds of ammonia ice crystals,
lofted to high altitudes by violent winds.



BREAKTHROUGHS IN TECHNOLOGY


HUBBLE SPACE TELESCOPE, the creation of ten thousand people over two
decades of inspired effort, is by far the most complex and advanced
space observatory ever built.  The HST project team produced major
technological breakthroughs in order to meet the most demanding
observing requirements in space-science history.

Support Structure:
Constructed of lightweight, low-expansion, hand-formed graphite-epoxy
tubes, the structure holds HST optical components aligned within
1/10,000 of an inch during two abrupt temperature changes every 96
minutes as HST orbits into and out of sunlight.

Pointing Control System:
The most accurate ever devised for astronomy, incorporating unique,
high-spin-rate gyroscopes shielded against vibration and
electromagnetic disturbances caused by space radiation and solar
flares -- reduces pointing instability to an angle less than the width
of a dime seen 200 miles away.

Ultraviolet Performance:
The ultraviolet optical system is the most capable ever launched for
astronomical observations in this region of the electromagnetic
spectrum.  It has reflecting surfaces of unprecedented cleanliness and
smoothness to maximize the amount of ultraviolet radiation available
for imaging and spectroscopic analysis.

Serviceability:
This is the first NASA space mission designed for regular Space
Shuttle maintenance and upgrading over a planned 15-year mission
lifetime.  Forty-nine types of key components, including gyroscopes,
are accessible and readily replaceable on orbit to maintain and expand
HST capabilities.

CURRENT CAPABILITIES

Q:  What was HST designed to do?
A:  HST was designed to provide three capabilities:
    1. High angular resolution -- the ability to image fine detail;
    2. Ultraviolet performance -- the ability to produce ultraviolet
images and spectra; and
    3. High sensitivity -- the ability to detect very faint objects.

Q:  What can HST currently do?
A:  HST currently provides the first two capabilities. First of all,
for the brighter sources:
    1. Computer processing can be used to bring out much finer image
detail than can be provided by ground-based telescopes. In addition,
    2. Corrective optics, to be provided by the first Shuttle
servicing mission, will bring this scattered light back into focus,
allowing HST to achieve its original design goal and reach very
distant stars and galaxies.

High angular resolution
of HST compared with a ground-based image of the globular cluster M14
and an image recorded by HST after computer processing show the
ground-based image heavily blurred by atmospheric turbulence and
unable to reveal individual stars in the cluster center.

Ultraviolet spectroscopy
of the star Beta Pictoris by HST reveals streams of circumstellar gas
(CS) falling into the star.  From earlier optical and infrared
observation, Beta Pictoris is known to be surrounded by an orbiting
disk of matter that may be a planetary system in the process of
formation.  The HST ultraviolet observations probe the central regions
of the system and provide new insights into its dynamics.

High sensitivity
will be achieved through correction of spherical aberration by the
first Shuttle servicing mission.  The current HST image of a star is
broadened by the effect of the aberration.  The corrected stellar
image will meet the HST design goal by concentrating 60 to 70 percent
of the light within a small region near the image center, enabling HST
to study much fainter objects.

SERVICING PLAN

Q;  How does Shuttle servicing fit into your plans?
A:  HST is designed to be serviced by Space Shuttle crews.  It has 49
different types of key components readily replaceable in space, and 74
replacement parts are available right now.  We have always planned
servicing missions, at roughly 3-year intervals, to maintain HST's
operational capability and to upgrade its scientific performance as
new technologies become available.

Q:  What will you do on the first mission?
A:  Our current baseline planning calls for replacement of the solar
arrays, correction of the spherical aberration, and replacement of
other components as necessary -- for example, gyroscopes -- in late
1993 or early 1994.

Q:  And on later missions?
A:  We'll replace remaining first-generation instruments, which
represent earlier technology, with much more advanced second- and
third-generation instruments to provide even greater capability,
particularly for ultraviolet and infrared observations.

First Servicing Mission
Replace Solar Arrays
Correct Optics with WF/PC 11
And Costar
Replace 2 gyroscopes

Wide Field/Planetary Camera, workhorse of the HST observing program,
will be replaced by an optically corrected camera by astronauts on the
first Shuttle servicing mission in late 1993 or early 1994.

Later Servicing Missions  (1995-2005)
Install second-generation instruments to broaden infrared and
ultraviolet capabilities
Install third-generation instruments to increase sensitivity and
provide finer imaging and spectral detail
Boost HST spacecraft to higher altitude as required
Service other HST components as necessary

THE GREAT OBSERVATORIES

Compton Gamma Ray Observatory
launched in 1991, is now investigating the most energetic systems and
violent events in the Universe.  Compton has already shown that the
puzzling gamma-ray "bursts" observed by earlier satellites are
distributed uniformly across the sky, rather than concentrated toward
the plane of our Galaxy -- challenging current theories of burst
origin in neutron stars and suggesting that some other mechanism must
be responsible. (In operation).

Advanced X-Ray Astrophysics Facility (AXAF)
will use specially designed mirrors to image X rays from supernova
remnants, high-temperature stellar atmospheres, galactic "halos" and
nuclei, and other high-energy objects.  In September, 1991, the
initial pair of AXAF mirrors passed a series of stringent performance
tests at NASA's Marshall Space Flight Center.  (In development).

Hubble Space Telescope (HST),
launched in 1990, is already making discoveries at the forefront of
science, including clouds of high-velocity gas spiraling into the
center of an accretion disk around Beta Pictoris and a stellar
"fountain of youth" in the ancient globular cluster 47 Tucanae.  HST
will receive upgrades through Shuttle servicing missions over its
15-year mission lifetime.  (In operation).

Space Infrared Telescope Facility (SIRTF)
will use optics cooled to extremely low temperatures in order to
detect millions of faint infrared sources across the sky.  Particular
targets include the dense, warm clouds of dust and gas that pervade
star-forming regions in our own and other galaxies.  SIRTF will build
upon the extraordinary success of NASA's Explorer-class Infrared
Astronomical Satellite, which carried out the first all-sky survey of
infrared sources between 1983 and 1985.  (Technology under
development).

Hubble Space Telescope,
launched in April 1990, is now in routine operation, chalking up a
succession of scientific accomplishments despite a number of technical
challenges.  The tracking of a rare, giant storm on Saturn, the
unexpected detection of numerous clouds of hydrogen gas near our
Galaxy, and the discovery of a stellar "fountain of youth" in 47
Tucanaae, together with the exciting spectroscopy of Beta Pictoris,
are only some of the triumphs recorded to date.

HST's current scientific capabilities are outstanding, and its future
capabilities will be even better.  The first Shuttle servicing
mission, in late 1993 or early 1994, will end the "jitter" caused by
the solar arrays and give HST the high sensitivity needed to observe
very distant stars and galaxies.  Later servicing missions will
install the powerful second- and third- generation instruments that
have been planned from the start.  With these scheduled performance
enhancements, HST will be able to achieve its original scientific
goals over a planned 15-year observing lifetime.


"The exploration of space ... is one of the great adventures of all
time, and no nation which expects to be the leader of other nations
can expect to stay behind ...

We choose to go to the Moon in this decade, and do the other things,
not because they are easy, but because they are hard, because that
goal will serve to organize and measure the best of our energies and
skills, because that challenge is one that we are willing to accept,
one that we are unwilling to postpone, and one that we intend to
win..."
                     -- President John F. Kennedy
                        September 12, 1962

Source:  NASA Status Report, April 1992


BACKGROUND

The Hubble Space Telescope (HST) was launched on April 24, 1990.  By
June 1990, two problems were discovered:  spherical aberration of the
primary mirror and jitter caused by the solar arrays.  Image
processing and spacecraft control software have compensated somewhat
for both of these problems, but servicing is necessary to fix them.
HST was designed for on-orbit servicing, to repair and refurbish the
observatory and to upgrade its capabilities by installing advanced
instruments.  On-orbit servicing will permit correction of the
spherical aberration and the solar array jitter.

MISSION GOALS and PLANNING

The primary objective of the first HST servicing mission is to correct
for spherical aberration in HST's primary mirror and replace faulty
solar arrays.

The major constraint on NASA's ability to service HST on this mission
is the amount of work that can be completed during the planned Space
Shuttle flight.  The current plan provides for 3 days of
extravehicular activity (EVA) servicing, a day to redeploy HST and
another day to assure the safe return of the Space Shuttle (for
example, by manually closing the cargo bay doors if necessary).  This
amount of on-orbit work time provides for two optical fixes -- the
Wide Field/Planetary Camera II (WF/PC II) and the Corrective Optics
Space Telescope Axial Replacement (COSTAR); replacement of the solar
arrays, two pairs of gyros and one gyro electronic box; and enough
additional time to replace another subsystem that will be identified
at a later date.

During the ongoing mission preparation, NASA is investigating methods
to improve the efficiency of the work, so that any extra EVA time
would provide a margin to assure the critical work required to restore
essential HST capabilities is completed.

MISSION OVERVIEW

Currently scheduled for launch in late 1993 -- early 1994, the orbiter
will rendezvous with HST on the third day of flight.  HST will then be
captured and secured in an upright position in the cargo bay for
servicing.  Working in pairs, on alternating days, the 4 EVA crew
members will be spending three 6-hour work days performing the
repairs.

Development has begun on astronaut simulations of on-orbit servicing
operations to rehearse and optimize EVA repair work at Johnson Space
Center's Neutral Buoyancy Simulator (these large water tanks simulate
the weightless environment of space).  Early EVA training on
individual components began this March.  Other key events that will
affect planning for the mission include the selection of a flight crew
and a Shuttle cargo integration review in late 1992.  Meanwhile,
planning teams, including representatives of NASA Headquarters,
Goddard Space Flight Center, Johnson Space Center, and Kennedy Space
Center, will continue working on detailed and comprehensive procedures
and time lines for this challenging mission.

MISSION CARGO
Wide Field/Planetary Camera II

The Jet Propulsion Laboratory team that built HST's Wide
Field/Planetary Camera (WF/PC) began developing a spare instrument in
1985.  When the Hubble's mirror was found to be flawed, NASA and the
WF/PC science team immediately began working on an optical correction
that could be built into WF/PC II.  The new design incorporates an
optical correction by the refiguring of relay mirrors already in the
optical train of the cameras.  A relay mirror for each camera is
polished to a new "prescription" that will compensate for the
incorrect figure on HST's primary mirror.  Small actuators will
fine-tune the positioning of these mirrors on orbit, ensuring the very
precise alignment that is required.

Through a servicing bay door built into the side of HST, astronauts
will slide out the 610-pound, wedge-shaped WF/PC I, as they would a
giant drawer, and replace it with WF/PC II.  The new instrument will
have three wide field cameras and one planetary camera instead of the
original eight in order to develop a system to align the corrective
relay mirrors on-orbit.  Improved Charged Coupled Devices (CCDs) that
were not available when the first WF/PC was built will be incorporated
in WF/PC II to improve its sensitivity, particularly in the
ultraviolet.

WF/PC II is proceeding within its budget and, despite the complexity
of the task, is on schedule to be delivered from the Jet Propulsion
Laboratory to NASA's Goddard Space Flight Center in the spring of
1993.  WF/PC II will be tested with spacecraft and ground system
simulators there before being sent to Kennedy Space Center to be
integrated with the Space Shuttle.

CORRECTIVE OPTICS SPACE TELESCOPE
Axial Replacement (COSTAR)

COSTAR was invented by the Hubble Space Telescope Strategy Panel, a
group of scientists and engineers brought together at the Space
Telescope Science Institute in the fall of 1990 to consider how to fix
HST.  Being built by Ball Aerospace under contract to NASA, COSTAR has
no detectors or cameras.  It will use precisely shaped mirrors to
correct for the spherical aberration.

Through a servicing bay door, astronauts will pull out the 487-pound,
phone-booth-sized High Speed Photometer (HSP) and install in its place
the identically sized COSTAR.  Once in place, COSTAR will deploy a set
of mechanical arms, no longer than a human hand, that will place
corrective mirrors in front of the openings that admit light into
three of HST's observing instruments (the Faint Object Camera, Faint
Object Spectrograph, and Goddard High Resolution Spectrograph).

COSTAR's corrective mirrors will refocus light relayed by HST's
primary mirror before it enters these instruments.  COSTAR will
restore the optical performance of these instruments very close to the
original expectations, at a level sufficient to conduct to original
science programs.

The HST team decided that COSTAR would displace the High Speed
Photometer because the photometer does proportionately less science
than any one of HST's other four instruments.

Less than a year after beginning development, COSTAR passed a major
milestone, critical design review.  The project remains within budget
and on schedule, with no major technical problems.

SOLAR ARRAYS

HST's deployable solar arrays, provided by the European Space Agency
(ESA), create a jitter problem that interferes with spacecraft
stability.  The arrays were designed to accommodate the expansion and
contraction caused by heating and cooling as the Hubble moves in and
out of daylight in its 90-minute orbits.  However, a compensation
device that allows for the expansion and contraction of the solar
array blankets does not expand and contract as smoothly as expected.
ESA has redesigned a set of space solar arrays to reduce the jitter to
an acceptable level.  A critical design review took place during
January 1992.  All participants in the HST program were pleased with
the redesign, and ESA is fully committed to its role as a partner in
the program.

GYROS

Three gyros are required to point and track HST; three more gyros are
on board as backups.  One of HST's six gyros failed in December 1990,
and a second one failed in June 1991.  Two of the four gyros contain
components that are suspected of causing the failures.  While these
failures have not affected HST's performance, replacing the failed
hardware will increase system reliability.  If time permits on the
servicing mission, astronauts will remove and replace two Rate Sensor
Units (RSU) -- each housing a pair of gyros -- and an Electronic
Control Unit (ECU).  The replacement units are flight-qualified spares
that are being rebuilt to replace the suspected point of failure (a
hybrid circuit).  The first RSU and ECU are scheduled to be delivered
to Goddard Space Flight Center in the summer of 1992; the second RSU
is to be delivered in the spring of 1993.

SERVICING/SUPPORT EQUIPMENT

From the very beginning, HST was designed for servicing in space, and
many of its subsystems were designed to be modular, standardized, and
accessible.  HST has 49 different modular subsystems designed for
servicing, ranging from small fuses to scientific instruments.
(Instruments, batteries, computers, and other essential components in
the equipment bays are accessible through doors for easy removal and
replacement.  These items, called Orbital Replacement Units, are
designed for servicing in space).  HST also features 225 feet of
handrails and 31 footholds to aid EVA crews in servicing tasks.  More
than 80 tools, ranging from screwdrivers to special hardware designed
specifically for HST servicing, are available for use on this mission.

CONCLUSION

The Hubble Space Telescope servicing mission is a challenging and
complex endeavor, but all elements of mission planning are on
schedule.  The Astrophysics Division will continue to report on the
evolution of plans for the HST servicing mission.
 

HUBBLE SPACE TELESCOPE (HST):  HST operations have returned to
normal following the recent safehold entry and recovery. Starting
on July 30, a chain of events caused HST first to enter an
inertial hold safemode followed by a hardware sunpoint safemode.
The first was caused by an incorrect ephemeris table that was
loaded into the spacecraft computer, and the latter by a problem
with an onboard computer software macro. Science observations
that were scheduled for execution during the safemode events are
being rescheduled. HST launched April 24, 1990 aboard the Space
Shuttle Discovery.

Article: 49616
Newsgroups: sci.space,sci.astro,alt.sci.planetary
From: [email protected] (Ron Baalke)
Subject: HST Explores Io
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 3 Oct 1992 02:31:07 GMT
 
Paula Cleggett-Haleim
Headquarters, Washington, D.C.                         October 2, 1992
(Phone:  202/350-1547)
 
Jim Elliot
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)
 
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)
 
RELEASE: 92-163
 
NASA'S HUBBLE TELESCOPE EXPLORES JUPITER'S VOLCANIC MOON IO
 
	Extended observations by the Hubble Space Telescope indicate that
Jupiter's moon Io has a smaller atmosphere than previously thought with very
dense regions possibly over volcanoes and surface frost, NASA announced today.
 
	The observations also show that despite continual volcanic activity,
Io's surface has remained largely unchanged since first photographed by the
Voyager spacecraft when it flew past the moon in 1979.
 
	The Hubble observations mark the first time astronomers have been
able to directly gauge the size of Io's tenuous atmosphere.  Sulfur and oxygen
emissions from the atmosphere indicate that it is at least three times smaller
than previously thought -- 1.5 Io diameters across instead of the previous
upper limit value of 5 Io diameters.
 
	These observations show that the atmosphere may be patchy, with very
dense regions having 1000 times higher pressure than adjoining, low-density
regions.  Likely sources for the atmospheric gas are sulfur dioxide from the
volcanoes, evaporation of surface frost in sunlit areas or material knocked
out of the surface ("sputtered") into the atmosphere.  The observations also
confirm that the surface contains sulfur dioxide frost.
 
	Hubble's observations reveal a new oxygen emission never before
detected from the torus, a giant ring of high-temperature gas encircling
Jupiter.  From these measurements, the density and the amount of oxygen
relative to sulfur in the torus have been determined.  Oxygen is the most
abundant component of the torus with about twice as much concentration as
sulfur.
 
Moon's Effects On Jupiter
 
	Though no larger than Earth's Moon, Io affects the immense planet
Jupiter on a grand scale.  Io's atmosphere feeds material to the torus
encircling Jupiter at Io's distance.  Understanding Io's atmosphere is
essential to understanding the plasma torus, which in turn affects Jupiter's
immense magnetosphere and aurorae.
 
	Sulfur from the volcanic plumes cannot escape directly into space to
fuel the plasma torus.  Instead, sulfur and oxygen might be stripped from Io's
atmosphere in a complicated interaction between the atmosphere and the
plasma torus.
 
	Observations of Io's atmosphere were made with Hubble's Faint Object
Spectrograph (FOS) by Melissa McGrath of the Space Telescope Science
Institute (STScI), Baltimore; John Clarke, University of Michigan and Darrell
Strobel, Gilda Ballester, Warren Moos and Paul Feldman of The Johns
Hopkins University, Baltimore.
 
	Io images were taken by Francesco Paresce, European Space
Agency/STScI; Paola Sartoretti, University of Padova and co-investigators with
the Faint Object Camera (FOC).  Additional images were taken by amateur
astronomer Jim Secosky with Hubble's Wide Field/Planetary Camera (WFPC).
 
	Earlier space probes revealed that Io has surface sulfur dioxide frost
appearing as bright white patches in visible images and that Io has a very
tenuous atmosphere, composed primarily of sulfur dioxide, with a surface
pressure 1 billionth that of Earth's atmosphere.
 
	Scientific progress on understanding Io has been slow since the 1979
Voyager observations.  Io is so small and one-half billion miles from Earth,
preventing ground-based telescopes from distinguishing Io's surface features.
 
	Because Io's atmosphere is primarily sulfur dioxide, atmospheric
studies can be undertaken best at ultraviolet wavelengths.  These wavelengths
cannot penetrate Earth's atmosphere for studies by ground-based telescopes.
 
Io's Surface Unchanged Despite Volcanism
 
	To look for possible surface changes, researchers compared FOC visible-
light images to a "synthetic" Voyager image modified to match Hubble's
resolution.  The astronomers concluded that Io's trailing hemisphere, known
to be more geologically active, has not changed noticeably in the 13 years
between Voyager and Hubble observations.
 
	Detailed analysis of the images is still being carried out to search
for less obvious changes.  Two small areas roughly 200 miles across seem to
have undergone slight change.
 
	This lack of large-scale change is mysterious because Io's volcanism
should resurface the moon at a rate of a few inches per year.  One possibility
is that there is a constant equilibrium between volcanic eruptions and
unknown processes which might remove or cover volcanic debris.  This
would preserve the general appearance of Io's surface over long periods.
 
	Io's surface looks remarkably different in ultraviolet (UV) light.
Regions which look bright in visible light are dark in UV.  The most likely
explanation is that large areas of Io are covered with a sulfur dioxide frost.
Because sulfur dioxide is a strong absorber of UV radiation, sulfur
dioxide-rich areas are dark in the UV and bright in visible light.
 
	Dr. Paresce points out that there also are regions that are bright or
dark in images taken at both wavelengths.  This suggests that the size of
sulfur dioxide grains also may play a role in brightness.  The reflectivity of
sulfur dioxide is very sensitive to the grain size at ultraviolet wavelengths.
 
	Amateur astronomer Jim Secosky made near-infrared images (7100
Angstroms) of Io which complement the FOC images by providing new
constraints on Io's surface composition.  Some models predict the presence
of basalts and polysulfur oxide on the surface.  But these dark compounds do
not show up in Hubble's longer wavelength images.  This further supports the
model for Io's surface being predominantly sulfur and sulfur dioxide.
 
	Secosky took HST snapshots of Io emerging from Jupiter's shadow to
look for evidence of frost evaporation which might have formed on Io while it
was chilled behind Jupiter.  This would have been evident if Io was 10
percent brighter than while emerging from eclipse.
 
	Secosky did not see any evidence of the "post-eclipse brightening"
phenomena which have been reported occasionally by ground-based observers
since 1964.  Secosky thinks his negative results mean that the post-eclipse
brightening effect, if real, may be driven by sporadic volcanic activity.
 
	The researchers continue developing models of Io's complex surface
structure and composition to account for Hubble's imaging and simultaneous
spectroscopic observations.  Because Io is the solar system's most dynamic
and evolving moon, Hubble will continue to be used for detecting changes in
Io's atmosphere and on its surface.
 
- end -
 
Editors Note:  Photographs and a video, "HST Studies Jovian Moon Io," are
available to media representatives by calling 202/453-8373.
 
HST Single Image                            HST Comparison Images
Color:  92-HC-671                            92-HC-672
B&W:   92-H-726                              92-H-727

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Einstein's brain is stored
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/  |_|/       |_____|/                     | in Wichita, Kansas.
 

HST: The first four batteries (#2,3,5 and 6) have been discharged
successfully under a battery reconditioning program started in
August. Recharging is in progress.  After an analysis of the
discharge and recharge profiles of the first four batteries,
reconditioning of the last two will be undertaken.  HST launched
April 24, 1990 aboard the Space Shuttle Discovery.
Contact: Jim Elliott (301) 286-6256

RELEASE:  92-168

     NASA's Hubble Space Telescope (HST) has photographed a striking
mirror-image of a very distant galaxy.

     The observations might unlock the secrets of the dark matter mystery
that have puzzled astronomers for decades.  Understanding the nature of
dark matter might lead to predictions of whether the universe will expand
indefinitely or collapse of its own gravity.

     The mirror image is seen through a huge cluster of foreground galaxies
located four billion light-years away.  The gravity of the galaxy cluster acts
as a natural lens or magnifying glass, bending, concentrating and focusing
the light of the distant galaxy into several images, each of which is bigger
and brighter than otherwise would be the case.

     "This rare combination of Hubble's powerful telescope mirrors and the
natural 'telephoto lens' gives astronomers new information on the nature of
distant galaxies," says Richard Ellis of Durham University, England.

     By studying how the natural lens bends the light, investigators also can
deduce the amount and location of mysterious "dark matter," thought to
make up most of the cluster's mass.

     Astronomers estimate that at least 90 percent of the universe consists
of material that does not emit any radiation detectable by current
instrumentation.  Although dark matter cannot be seen directly, the
phenomenon of gravitational lensing provides a powerful probe in the
search for dark matter.

     "We already knew from ground-based images that this cluster of
galaxies could act as a gravitational lens," says Ellis.  "The remarkable
feature of the new data is the detail with which we can study background
galaxies by combining the lensing phenomenon with the excellent image
quality possible with HST.

     "The unique combination has allowed us to measure the bending power
of the lens very precisely, enabling us to determine the distribution of
matter in the cluster regardless of whether or not it emits light."

     Ellis and co-researchers Dr. Warrick Couch (University of New South
Wales, Australia), Dr. Ray Sharples and Ian Smail (Durham University)
made the discovery when observing the cluster called AC114 in one of the
first long exposures with the spacecraft's Wide Field Camera.

     Two, 6-hour exposures revealed a striking pair of faint objects close to
the center of the cluster.  Each image has a faint structure attached to it.
These structures show perfect mirror-symmetry, as expected if both are
lensed images of the same source.  The images are unusually far apart for
a lensed system, implying AC114 has a dense massive core.

     "Despite their wide separation, the high degree of symmetry and near-
identical colors of the objects are a strong indication that they are images
of the same source, supporting the hypothesis that we have discovered a
very massive lens," Ellis explained.

     "We believe that we are looking at a very faint, distant galaxy
undergoing an energetic period of star formation.  At first we thought we
were privileged to see such a dramatic feature in the first long exposure
with Hubble, but we now believe that similar, highly magnified, multiple
images will be observed when the spacecraft looks through the centers of
other massive clusters."

A Zoom Lens In Space

     Albert Einstein was the first to point out that gravitational fields
deflect light as well as matter.  The gravitational field of a massive
object -- such as a cluster of galaxies -- will deflect light rays from
more distant sources seen close to the cluster center.

     This has the effect of shifting their apparent positions and magnifying
and distorting their shapes and brightness.  The greater the cluster's
mass, the greater the effect.  If the cluster is dense enough it can create
several images of a single distant object.

     Multiple-lensed systems provide astronomers with a powerful probe to
investigate the form of the gravitation field of the lens.  Ellis and fellow
researchers have developed numerical models based on Einstein's theory.

     Starting from the location and shapes of the first two images, they
predict the existence and location of further images.  The remarkably blue
color and unusual morphology of the source has enabled them to identify a
third fainter image.

     This, and any further images similarly located, will enable the group to
refine their lens model.  The goal is to make it precise enough to find the
distances and properties of hundreds of very faint galaxies viewed through
the cluster.

     These objects are far too faint for more traditional distance-measuring
techniques and promise to reveal the nature of the very early universe.
"Just as in school optics, once you know the basic properties of a lens, you
can examine the images it produces and figure out how far away the
sources are," Ellis explained.

The Search for Dark Matter

     Although dark matter cannot be seen, its existence has been inferred
from its gravitational influence on the motions of galaxies in clusters.
Clusters like AC114 are not only very useful probes of the galaxies at the
limits of the universe, their lensing properties also show how much dark
matter they contain.

     More importantly, the amount can be measured directly via
gravitational lensing.  Ellis' model for AC114 provides an important new
measurement of the amount of dark matter in AC114 which agrees with
previous estimates based on the motions of its galaxies.

     It also suggests, however, that the dark matter is more concentrated
toward the center of the cluster than the individual galaxies.  This is
contrary to the predictions of models in which the dark matter is made up
of subatomic non-interacting particles.

     The group plans to extend this work to other clusters at different
distances.  This will allow the researchers to probe the universe at different
times in the distant past (because of the effect of light-travel time).  Such
observations will enable them to follow the evolution of the dark and visible
matter independently.

     "We intend to use HST's superlative image quality to search for similar
lensed systems in other rich clusters," said Ellis.  "Using these we will be
able to directly probe the changes in the structure of clusters as they
evolve and grow in the universe."

     The Space Science Telescope Institute is operated by the Association of
Universities for Research in Astronomy, Inc., for NASA under contract with
the Goddard Space Flight Center, Greenbelt, Md.  The Hubble Space
Telescope is a project of international cooperation between NASA and the
European Space Agency.

                                           - end -

EDITORS NOTE:  A photograph of the gravitational lens in galaxy cluster
AC114 is available to news media by calling the NASA Headquarters
Broadcast and Imaging Branch at 202/453-8375.

          Color:     92-HC-674
          B&W:     92-H-730

A videotape to accompany this release containing animation of the
gravitational lens also is available at the Broadcast and Imaging Branch.

HUBBLE SPACE TELESCOPE

       A successful engineering test of the Faint Object Camera (FOC) f/48 was
conducted following high voltage problems last month.  All other subsystems and
science observations are performing nominally.  Both the Planetary Camera and
the Faint Object Spectrograph (FOS) were used to make atmospheric observations
of the planet Saturn. The spectral observations were taken from several
latitudes along the central meridians.  All of the observations were received
and reported to look fine.  The Fine Guidance Sensors were used to make
astrometric observations of the giant o-type star AV488 in the small Magellanic
Cloud. The target acquisitions appeared to be successful.  The spectrum showed
a complex structure.  HST launched April 24, 1990 aboard the Space Shuttle
Discovery.
 

     [Forwards removed.]

                  I N T E R O F F I C E   M E M O R A N D U M

                                        Date:     23-Oct-1992 10:09am EST
                                        From:     VMSMail User PORTER
                                                  PORTER@LANDO@MRGATE
                                        Dept:
                                        Tel No:

TO:  VHOLTZENDORF@GUCCI@MRGATE

CC:  PORTER@LANDO@MRGATE

Subject: Space Telescope testimonial for press kit

			SPACE TELESCOPE SCIENCE INSTITUTE

	The Space Telescope Science Institute, located in Baltimore,
Maryland, is the astronomical research center which operates the Hubble
Space Telescope as an international observatory.  The Institute is operated
for NASA by the Association of Universities for Research in Astronomy, Inc.
With a staff of astronomers, computer scientists, and technicians, the
Institute provides long-term guidance and support for the science mission
of the Hubble Space Telescope, and provides a means for disseminating and
utilizing the data from the telescope.  The OpenVMS VAX family of computer
systems are an integral part of the system supporting the Hubble Space
Telescope. 

	"We are porting many small to large C and FORTRAN applications that
perform a variety of tasks," stated Joel Richon, Computer Scientist at the
Space Telescope Science Institute.  "For many of these applications,
porting to the Alpha AXP platform takes little or no effort, and is much
the same as any porting task.  Training and literature from Digital about
Alpha AXP porting helped us anticipate and solve most of the problems we
did encounter," Richon added. 

	"The performance on the Alpha AXP system ranges from fast to
unbelievably fast.  One particular application completed so quickly that we
thought it had crashed because of a porting problem; instead the
application had completed successfully." 

	"Our port of large FORTRAN applications is going quite smoothly and
I believe our applications will be more robust and reliable on Alpha AXP and 
VAX platforms after going through the porting effort," added Joel Richon. 

	Contact:  Joel Richon, Computer Scientist
		  The Space Telescope Science Institute
		  Baltimore, Maryland
		  Telephone:  (410) 516-5451

Article: 2451
Newsgroups: sci.space.news
From: [email protected] (Ron Baalke)
Subject: Hubble Observes Most Distantly Known Galaxy in Universe
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 14 Nov 1992 02:29:29 GMT
 
Paula Cleggett-Haleim
Headquarters, Washington, D.C.                      November 13, 1992
(Phone:  202/358-0883)
 
Jim Eliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)
 
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4757) 
 
RELEASE:  92-203
 
HUBBLE OBSERVES MOST DISTANT KNOWN GALAXY IN UNIVERSE
 
	NASA's Hubble Space Telescope (HST) has revealed a chain of 
luminous knots in the core of the most distant known galaxy -- one that 
existed in the infancy of the universe and is located more than 10 billion 
light years from Earth. 
 
	"These knots could be giant clusters of stars.  If that is so, then 
each  knot would contain about 10 billion stars and would be about 1,500 light 
years across," said Dr. George Miley of Leiden University in the Netherlands 
and leader of the international astronomer team which examined the galaxy.
 
	An alternative theory is that the knots are gas or dust clouds caught 
in a "searchlight" beam of energy from a massive black hole hidden at the 
galaxy's core.
 
	The galaxy's great distance from Earth indicates that it was formed 
only 1 or 2 billion years after the Big Bang, which marked the beginning of 
the observable universe.  Most galaxies probably formed during this early 
epoch.
 
	The new photos, taken with the HST's wide field and planetary 
camera, reveal detail ten times better than photographs previously taken 
with ground-based telescopes.
 
	The galaxy, designated 4C 41.17, also is known as a radio galaxy.  
Radio galaxies produce powerful, extended radio emissions.  Several have 
been discovered by this international team in the past few years at great 
distances from Earth.
 
	In the case of 4C 41.17, astronomers presume that a massive black 
hole, rotating in the core of the galaxy, is producing twin jets of particles 
moving at enormous speed.  The energy from the jets would be the source of 
the radio emissions.
 
	The Hubble photographs are remarkably similar to images of the galaxy 
produced on the basis of the radio emissions, Miley said.
 
	These corresponding images suggest that the high velocity particle 
jets compress gas and dust along their paths, triggering the formation of 
new stars.  This would account for the elongated optical appearance of the 
galaxy.
 
	If this explanation is accurate, the knots along the jet paths would be 
clusters of stars in "enormous numbers, the products of the highly disturbed 
inner region of the primeval galaxy," Miley said.
 
	It also is possible, said Miley, that the light photographed by the HST 
is not due to stars along the jet paths, but rather is light from a disk of 
material surrounding the black hole which is being scattered off clouds of 
gas or dust.  
 
	An active galactic nucleus of this description is called a quasar.  It 
is hidden from optical view by a thick dust shroud which allows light to escape 
only along the radio or jet axis.
 
	Hubble can help discriminate between these possibilities by further 
studying the colors and other properties of these and similar objects.  After 
the scheduled Space Shuttle servicing mission for Hubble in late 1993,  HST 
then can be used to carry out detailed studies of many galaxies at distances 
comparable with 4C41.17.  
 
	"More than 50 are now known," said Miley, "observing them with the 
renewed Hubble would provide us with an important new window through 
which we can glimpse the early history of our universe."
 
	The observations of galaxy 4C 41.17 were carried out by Miley and co-
investigators Kenneth Chambers, of the University of Hawaii; Wil van Breugel 
of Lawrence Livermore National Laboratories of the University of California; 
and Duccio Macchetto of the Space Telescope Science Institute, Baltimore 
and the European Space Agency.  The results will be published in the 
December 20 issue of Astrophysical Journal Letters.
 
	This research was supported by the Netherlands Organization for the 
Advancement of Pure Research, the Space Telescope Science Institute, the 
European Space Agency, NASA, the European Economic Community, NATO 
and the U.S. Department of Energy. 
 
	The Hubble Space Telescope is a project of international cooperation 
between NASA and the European Space Agency.
 
- end -
 
Editors Notee:  A photograph to illustrate this story is available to media 
representatives through NASA's Broadcast and Imaging Branch, (202/453-8375).
                        B&W               
                     92-H-748          
 
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Give people a second 
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | chance, but not a third. 
|_____|/  |_|/       |_____|/                     | 
 

Article 2471 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!nntpd.lkg.dec.com!news.crl.dec.com!deccrl!decwrl!purdue!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: HST Briefing on Possible Black Hole
Message-ID: <[email protected]>
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  HST
Sender: [email protected] (Usenet)
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Reply-To: [email protected]
Organization: Jet Propulsion Laboratory
Date: Tue, 17 Nov 1992 05:13:15 GMT
Approved: [email protected]
Lines: 54

Paula Cleggett-Haleim
Headquarters, Washington, D.C.            November 16, 1992
(Phone:  202/358-0883)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)


NOTE TO EDITORS:  N92-98

BRIEFING NOV. 19 ON HUBBLE IMAGE OF DISK AROUND POSSIBLE BLACK HOLE

     Hubble Space Telescope's first image of a giant dust disk 
orbiting a suspected black hole will be the subject of a media 
briefing Thursday, Nov. 19, 1992, at 1:00 p.m. EST in the NASA 
auditorium, 400 Maryland Ave., S.W., Washington, D.C.

     Dr. Walter Jaffe, of Leiden Observatory, The Netherlands, 
will present this recent finding and show an image clearly 
depicting the Frisbee-shaped disk.  The image provides 
astronomers with the first clear view of the disk's bright 
hub, which presumably harbors a black hole.

     The disk is at the core of galaxy NGC 4261, chosen 
because it is one of the dozen brightest galaxies in the Virgo 
Cluster, located 45 million light-years away.

     A video featuring animation of the disk fueling the black 
hole will be available at the NASA Headquarters Broadcasting 
and Imaging Branch by calling 202/453-8383.  Views of the 
galaxy's center using stills from ground-based observatories 
and Hubble also are on the video.

     Host Dr. Stephen Maran, from NASA's Goddard Space Flight 
Center, Greenbelt, Md., will be joined by veteran panelists 
Dr. Bruce Margon, Professor of Astronomy and Chairman of the 
Department of Astronomy, University of Washington, Seattle, 
and Dr. Daniel Weedman, Professor of Astronomy at Pennsylvania 
State University, University Park.

     The briefing will be carried live on NASA Select 
television, Satcom F-2R, Transponder 13, 72 degrees west 
longitude, frequency 3960.0 MHz, audio 6.8 MHz.  Questions 
will be taken from NASA centers.

- end -
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Learn to recognize the
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | inconsequential, then 
|_____|/  |_|/       |_____|/                     | ignore it.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.             November 19, 1992

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.



RELEASE:  92-208


     Astronomers using NASA's Hubble Space Telescope (HST) have gotten their
best look yet at the disk of material that surrounds and is being pulled into a
suspected black hole.

     The disk is at the core of a galaxy in the Virgo Cluster 45 million
light-years from Earth. Dr. Walter Jaffe of Leiden Observatory in The
Netherlands said the disk is tipped about 60 degrees -- enough to provide
astronomers with a clear view of the galaxy's bright hub.

     "The nucleus is probably the home of a black hole with a mass 10 million
times that of our sun," Jaffe said. "This is our best view to date of the
immediate surrounding of the nucleus of an active galaxy," the name given
galaxies that emit especially strong radiation indicating that they harbor
powerful energy sources.

     "This is the first case where we can follow the disk's gas in an orderly
way down to the immediate environment of the black hole," said co-investigator
Dr. Holland Ford of The Johns Hopkins University in Baltimore.

     The observations, made with the Wide Field/Planetary Camera (WF/PC) in the
planetary camera mode, make a strong contribution to mounting evidence for the
existence of black holes in the universe, the two astronomers said.

     A black hole is a theoretical object that is believed to form after a
massive star collapses.  The star's matter is so densely compacted that it has
a powerful gravitational pull that traps all matter that comes near it.

     Black holes to date are theoretical because their gravitational pull is so
great that not even light can escape.  Therefore, they cannot be seen.
Astronomers infer a black hole's existence by its gravitational influence on
the motion of stars and other material near it.

     The galaxy, designated NGC 4261, was selected for study because it is one
of the brightest in the Virgo Cluster.

     "The galaxy is unremarkable in visible light," said Jaffe. "However,
observations with radio telescopes show a pair of opposed jets emanating from
the nucleus and spanning a distance of 88,000 light-years." Spectroscopic data
from the Observatory del Roque de los Muchachos in the Canary Islands show
ionized gas in the nucleus moving at speeds approaching several million miles
an hour, or one percent of the speed of light.

     "Most astronomers believe both phenomena, which have been seen earlier in
radio galaxies and quasars (active nuclei of remote galaxies), to be caused by
material being swallowed by massive black holes hiding in the nuclei of large
galaxies," said Ford.

     The dark, dusty disk which is 300 light-years across, represents the cold
outer region which extends inwards to within a few hundred million miles of the
suspected black hole.  This disk feeds matter into the black hole, where
gravity compresses and heats the material to tens of millions of degrees.  Some
hot gas squirts out from the black hole's vicinity like twin streams of water
from a lawn sprinkler.

     "The spin axis of the disk orients the radio jets," said Ford. "The
cooler, outer regions of the washer-shaped disk confine the ionizing radiation
from the hot interior into a pair of cones whose axes are parallel to the radio
jets."

     Because dust and cool gas (neutral hydrogen) are not normally found in
elliptical galaxies, the presence of a disk at all provides a mystery.  Much of
the dust should have been destroyed quickly by the hot gas in the galaxy.  One
possible explanation is that the dust is a remnant of a spiral galaxy that was
swallowed by NGC 4261 in the recent past.

     After the scheduled Space Shuttle servicing mission for Hubble in late
1993, the researchers hope to use spectroscopy to study the motion of the gas
within a few dozen light-years of the black hole.  This might allow them to
prove the existence of the black hole by accurately measuring its mass.

     The researchers also hope to use spectroscopy to infer the thickness and
shape of the inner parts of the disk that are too small to be seen even with
the HST.


     The results are to be published in the Astrophysical Journal.
Co-investigators with Ford and Jaffe are Robert O'Connell (University of
Virginia, Charlottesville), Laura Ferrares (Johns Hopkins University,
Baltimore) and Frank van den Bosch (Leiden Observatory, The Netherlands).

     The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency.
 

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                        November 24, 1992



EDITORS NOTE:  N92-103


        Hubble Space Telescope astronomers will present the first detailed
images of galaxies as seen more than 4 billion years ago at a briefing on
Tuesday, Dec. 1, at 1 p.m.  EST in the NASA auditorium, 400 Maryland Ave.,
S.W., Washington, D.C.

        Serendipitously, the Hubble images also may have revealed the farthest
cluster of galaxies ever seen, located 10 billion light-years away.

        Dr.  Alan Dressler, Carnegie Institution, Washington, D.C., will
describe the shapes and evolution of these primordial galaxies.  The Hubble
pictures are sharp enough to distinguish between the various forms of galaxies.

        Dr.  Peter Stockman, Acting Director of the Space Telescope Science
Institute, will join host Dr. Stephen Maran, from NASA's Goddard Space Flight
Center, Greenbelt, Md., with veteran panelists Dr. Bruce Margon, Professor of
Astronomy and Chairman of the Department of Astronomy, University of
Washington, Seattle, and Dr. Daniel Weedman, Professor of Astronomy at
Pennsylvania State University, University Park.

Galileo Flyby Briefing

        Originating from NASA's Jet Propulsion Laboratory, Pasadena, Calif., at
2 p.m.  EST, project officials will discuss the Galileo Earth flyby to occur on
Dec. 8 and scientific observations of the Earth and moon.

        William J. O'Neil, Galileo Project Manager, will describe the flyby
maneuver, the third in Galileo's Venus-Earth-Earth gravity assist trajectory,
and outline plans for the mission to Jupiter.

        Dr.  Torrence V. Johnson, Galileo Project Scientist, will discuss
planned scientific activities, which include first-time surveys of the
north-polar regions of the moon.  Galileo also will observe the Earth for a
period of more than a week and will calibrate its instruments for the Jupiter
mission of 1995-1997.

        Both briefings will be carried live on NASA Select television, Satcom
F-2R, Transponder 13, 72 degrees west longitude, frequency 3960.0 MHz, audio
6.8 MHz.

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                  December 1, 1992

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.

RELEASE:  92-213


        Looking deeply into the universe and far back in time, NASA's Hubble
Space Telescope (HST) has found some suspected ancestors of today's galaxies.

        The Hubble images reveal that star-forming galaxies were far more
prevalent in the clusters of the younger universe than in modern clusters of
galaxies near us today.

        "The results have important implications for theories of how galaxies
have evolved since the beginning of the universe 15 billion years ago," said
Dr. Alan Dressler of the Carnegie Institution, Washington, D.C.

        Serendipitously, the Hubble observations also might have uncovered the
most distant galaxy cluster yet seen.  The cluster might be as far as 10
billion light-years, at a "look-back" time corresponding to the early epoch of
galaxy formation.

        A principal goal for the HST is to trace galaxy evolution through
direct observations.  This is very difficult to achieve with ground-based
telescopes because the tiny images of distant galaxies smear into faint blurs
when viewed through Earth's atmosphere.


        HST images of a pair of remote clusters of galaxies, located 4 billion
light-years away, allow astronomers to distinguish, for the first time, the
shapes of galaxies which existed long ago.

        The pictures, taken with HST's Wide Field/Planetary Camera in Wide
Field Camera mode, are so detailed that they show a full range of galaxy types
inhabiting the universe of 4 billion years ago -- elliptical, spiral, distorted
and irregular forms.

        The images also reveal galaxies in collision.  Some are tearing
material from each other.  Others are merging into single systems.

        Dressler said the pictures are sharp enough to distinguish between
various forms of spiral galaxies, whose distinctive swirl patterns are outlined
by vigorous star formation.

        "This shows us that clusters billions of years ago contained not only
the elliptical and S-zero galaxies like those dominating their descendant
clusters today, but also several times as many spiral galaxies," said Dressler.
S-zero galaxies are lens-shaped, featureless galaxies that may be the
transition between spiral and elliptical galaxies.

Disappearing Galaxies

        "The new Hubble data are the first unambiguous sign of the influence of
environment on the form of a galaxy" said Dressler. "Clearly, spirals were
common in clusters in the distant past, but they have largely disappeared or
changed form by now."

        Base upon the HST pictures and the results of earlier research with
ground-based telescopes, the team thinks that the rapid decline in the spiral
galaxy population can be explained by three mechanisms -- merger, disruption
and fading.

        HST reveals many examples of strong galaxy interactions or mergers in
one of the clusters.  This is evident by the presence of "tails" distorting the
shapes of some galaxies.  The tails probably are caused by tidal effects where
the gravitational pull between closely passing galaxies stretch and disrupt
their stellar distributions.

        The result is that many ancient spirals might have merged to form giant
elliptical galaxies or simply been torn apart and dispersed by the violence of
what Dressler calls the "Cuisinart environment."


        Dressler, however, believes that violent collisions are not the whole
story of the missing spiral galaxies.  His earlier research indicated that
bursts of star formation also were much more common in the past.  When the star
formation subsided in many of these early spiral galaxies, they may have faded
and are unnoticed in today's nearby clusters.

Most Distant Galaxy Cluster

        The HST observations also may have discovered the farthest cluster of
galaxies ever seen, located 10 billion light-years away.  The HST picture
resolved a cluster of about 30 very faint objects.

        "The smaller, more compact appearance of the objects suggests that they
are in the background, much further away than the foreground galaxies," said
Dressler.

        Additional evidence comes from the presence of a quasar possibly among
the faint objects.  Ground-based spectral observations of the quasar's
redshift, an indicator of cosmological distances, place the quasar at a
distance of 10 billion light-years.

        Quasars are theorized to be the extraordinarily bright, active cores of
primordial galaxies.  Quasars were prevalent in the early universe and hence,
most are located out at 10 billion light-years.

        "Though the superposition of the cluster objects and the quasar could
be a coincidence, both are so unusual that there is good reason to believe that
all are members of the same cluster" said Dressler.

        The bright spots which might accompany the quasar do not resemble the
elliptical and spiral galaxies of today, according to Dressler. "Conceivably,
the objects might not be separate galaxies but rather 'hot spots' in galaxies
whose full, extended forms are too faint to be seen in the Hubble
observations."

        Dressler suggested that the small spots seen in the more distant
cluster could be sites of vigorous star formation.  This would explain their
blue colors, because young, massive stars are brightest in blue and ultraviolet
light.

        "If the cluster is as far as the quasar, then it will offer an
unprecedented opportunity to learn how galaxies formed.  With so many objects,
it seems likely that among them are the ancestors of common galaxies like our
own Milky Way."


        The team believes that the further study of this cluster and similar
ones could provide a major breakthrough in seeing galaxies in the very act of
formation.

        The research was carried out by Drs. Dressler, Augustus Oemler of Yale
University, James E. Gunn of Princeton University and Harvey Butcher of the
Netherlands Foundation for Research in Astronomy.

        When HST's full optical capabilities are restored during a Space
Shuttle servicing mission in late 1993, HST will be able to resolve the
morphology of these very young galaxies.  Hubble will be capable of showing the
evolution of galaxy form over a wide range of environments and in even earlier
epochs.  This will greatly aid astronomers in their efforts to understand this
key piece of the cosmological puzzle.

        The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency.

Article: 102
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: hst_status_11_25_92
Sender: [email protected] (USENET News System)
Organization: Space Telescope Science Institute
Date: Tue, 1 Dec 1992 21:57:11 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #773
 
PERIOD COVERED:  0800 EST 11/25/92 - 0800 EST 11/30/92
 
Daily Status Report as of 335/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed FOS/BL 4110 (Massive O Type Stars in Different Galaxies)
 
       The Faint Object Spectrograph was used to make observations of
       Massive O-type star AV-238 located in the Large Magellanic Cloud.
       The binary search and peakup were received in real time and
       displayed. The peakup had maximum counts near the end of the scan.
       Seven sets of observations were taken. All were reported to be okay,
       showing good spectra. 
 
   1.2 Completed Four Sets of WFC 4105 (HST Medium Deep Survey High Latitude) 
 
       Four sets of observations were made using the Wide Field Camera to
       make a medium-deep high latitude sky survey. The first three sets of
       observations were reported to be okay. The third set was received
       and displayed. The exposure time was shortened by a few minutes
       because of a loss of lock which delayed the start of the exposure. 
 
   1.3 Completed WFC 3917 (HST Medium Deep Survey Part 1)
 
       Six images were taken with the Wide Field Camera in parallel with
       the prime science observations. The targets of interest were stars,
       normal and active galaxies, and possible solar system objects. All
       six images were received and displayed, and reported to be okay. 
 
   1.4 Completed Two Sets of WFC/PC 4109 (WF/PC Calibration Rapid Internal
       Monitor) 
 
       Both the Wide Field Camera and the Planetary Camera was used to take
       two sets internal flat observations checking for different forms of
       contamination. Both sets were monitored, and no problems were
       reported. 
   
   1.5 Completed Ten Sets of PC 3603 (Snapshot of Protoplanetary Nebulae)
 
       The Planetary Camera was used to take ten sets of of three different
       protoplanetary systems (Variable star TX Camelpardilis, PK215-24D1,
       and V384 Persei). All of the observations showed objects located in
       the expected CCDs. They were reported to be okay. 
 
   1.6 Completed Three Sets of PC 4163 (Solar Nebulae Surrounding Pre-main
       Sequence)
 
       A total of five Earth flat images were taken during three individual
       observation periods using the Planetary Camera. All were received
       and displayed. Of the five Earth flats, one was underexposed, and
       four were saturated. 
 
   1.7 Completed FOS/BL 4081 (Spectra for QSOs with Z>2.0 Augmentation)
 
       The Faint Object Spectrograph was used to make ultraviolet spectral
       observations of the quasar 1246-057 looking for broad absorption
       lines. The red shift of the quasar is about Z=2.0. The OSS conducted
       routine monitoring, and no problems were reported. 
 
   1.8 Completed PC 4347 (WF/PC Calibration, Flood Retention Test)
 
       The Planetary Camera was used with filter F439W to make Three Earth
       flat calibration images. All three images were received and
       displayed. Of the three flats, one was saturated, one was under
       exposed, and the last was okay. 
 
   1.9 Completed Three Sets of PC 3698 (Survey of 102 Markarian Galaxies II) 
 
       The Planetary Camera was used to make One observation of Markarian
       galaxy NGC-5548, and two observations of Galaxy MARK 246. All of the
       observations were received and displayed. The targets were reported
       to be visible in the expected CCD. The observations were reported to
       be okay. 
 
   1.10 Completed PC 2266 (Post Asymptotic Giant Branch Evolution)
 
       The Planetary Camera was used to make two observations of the
       planetary nebula SMC-SMP7-P located in the Small Magellanic Cloud.
       Both of these observations were received and displayed in the OSS.
       The shutter remained closed during each of these observations
       because the guide star acquisition failed. 
 
   1.11 Completed FOS/BL 3270 (Spectra Polarimetry of QSOs, Blazars, and 
        AGNs)
 
       The Faint Object Spectrograph was used to make four ultraviolet
       spectral observations below 3000 A0 of Quasar MARK231 which shows
       periodic brightness variations. All of the observations were
       received and displayed. The data from the binary target acquisition
       had eight groups, and looked good. The observations were noisy, but
       showed some structure in the spectra. 
 
   1.12 Uplinked Updated Ephemeris Tables, Per MOSES 2871
 
        Uplinked at 330/1208Z, 334/0505Z, and 332/1218Z.
 
   1.13 Completed FOS/BL 1144 (Linear Extent in Lyman Alpha Clouds)
 
       The Faint Object Spectrograph was used to make observations of the
       Lyman Alpha Cloud around Quasar TON155. The observations were
       monitored by the OSS, and no problems were reported. 
 
   1.14 Completed FOC/96 3671 (Spectroscopy of Hydrogen Poor Nebulae)
 
       The Faint Object Camera (f/96) was used to make observations of
       planetary nebula PK81-14D1. This planetary nebula is rich in metals,
       but poor in hydrogen. The observations were executed as scheduled,
       and no problems were reported. 
 
   1.15 Completed Two Sets of FOC/96 3790 (Polarization Imaging of Radio
        Galaxies) 
 
       The Faint Object Camera was used to take two observations of radio
       galaxy 3C109 in the ultraviolet using filter F320W and two
       polarizers. The observations were initiated as scheduled. No
       problems were reported. 
 
   1.16 Completed PC 4106 (HST Medium Deep Low Latitude)
 
       The Planetary Camera was used to take high latitude observations in
       parallel mode to provide for serendipitous discoveries and to obtain
       data for a basic sky survey. The OSS monitored the observations, and
       assessed the quality of the data. No problems were reported. 
 
   1.17 Completed FOS/BL 3600 (Oscillation Flares and Topography of AE 
        Aquarii)
 
       The Faint Object Spectrograph was used to make rapid read-out mode
       (Once per Second) to take high time resolution spectral observations
       of variable star AE Aquarii. The acquisition was via an onboard
       peakup. Doppler and time-delayed tomography were used to map the
       ultraviolet emission regions. The observations were executed as
       scheduled. All of the observations were reported to be okay. 
 
   1.18 Completed Two Sets of PC 3912 (Cores of Early type Galaxies)
 
       The Planetary Camera was used to take two sets of observations of
       the active core of galaxy NGC-3599. The first set of observations
       contained two images which contained the target in the expected CCD.
       The second set of observations contained three images, which had a
       dead column passing through the center of the image. 
 
   1.19 Completed Two Sets of PC 3230 (PC PSF and Focus Monitoring 2)
 
       The Planetary Camera was used to make two sets of point spread
       function and focusing test observations of two standard stars
       (SAO62717 and SAO62925). All of the observations were reported to
       have the point spread function centered on the Baum spot. 
 
   1.20 Completed Four Sets of FOC/96 4069 (Ultraviolet Spectra of High
        Redshift Quasars) 
 
       The objective prism  on the Faint Object Camera (f/96) was used to
       take ultraviolet spectral observations of high red shift quasar
       Q1209+154 to investigate the opacity of the intergalactic medium in
       the Lyman Continuum. Three observations were received and displayed.
       The exposure times for each of the first two observations were
       shortened by several minutes due to the losses of lock. Otherwise,
       all three observations were reported to be okay. 
 
   1.21 Completed PC 4140 (Rapid Internal Monitor)
 
       Two internal flat observations were made with the Planetary Camera
       to look for new forms of contamination. Both observations were
       received and displayed. The first observation was saturated, and the
       second was okay. 
 
   1.22 Complete PC 4093 (Snapshot of 102 Markarian Galaxies)
 
       The Planetary Camera was with filter F785LP used to take one image
       of Markarian galaxy MARK413 to study its morphology and nuclear
       luminosity function. The observation was received and displayed. It
       was reported to be okay. 
 
   1.23 Complete HSP/POL 2952 (X-Ray Binaries)
 
       The High Speed Photometer was used to measure the photometric and
       Polarimetric light curves of the x-ray binary system Cygni X-1 (aka
       HDE226868). The observations were executed as scheduled, and no
       problems were reported. 
   
2.0 FLIGHT OPERATIONS SUMMARY:
 
 
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 52
                                        Successful : 48
 
                                          (Four Failed)
 
                          Scheduled Reacquisitions : 38
                                        Successful : 38
                                    Losses of Lock : 8
 
                           (329/1631,
                            334/0234,1214,1841,2152,2244,
                            335/0301,0839Z)
 
   2.2 FHST Updates: 
 
                              Scheduled : 76
                             Successful : 74
 
 
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: 
 
       The Flight Software Version FSW 8.2 release was uplinked 25 Nov.,
       1992. This release changed the Safemode Recovery Load to reflect the
       three RGA configuration now used for PCS control. 
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Five Sets of WFC 4713 (WF/PC Cal:WFC internal Delta Flats)
 
   3.2 Complete FOS/RD 3647 (Star-Forming Histories of Elliptical Galaxies)
 
   3.3 Uplink Updated Ephemeris Tables ,Per MOSES 2871
 
   3.4 Complete WFC 1297 (GTO High Latitude Parallel Program)
 
   3.5 Complete Two Sets of FOC/96 3747 (High Resolution Observations of 
       Cataclysmic Variables)
 
   3.6 Complete HSP/POL  2952 (X-Ray Binaries)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS: Nothing at this time
 
                                -END-
 

Article: 104
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: hst_status_11_30_92
Sender: [email protected] (USENET News System)
Organization: Space Telescope Science Institute
Date: Wed, 2 Dec 1992 20:22:47 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #774
 
PERIOD COVERED:  0800 EST 11/30/92 - 0800 EST 12/01/92
 
Daily Status Report as of 336/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed Five Sets of WFC 4713 (WF/PC Cal:WFC internal Delta Flats)
 
       The Wide Field Camera was used to take a series of internal flat
       observations using 18 different filters to look for changes in the
       quantum efficiency of the CCDs which occurred after the WFPC
       decontamination operations. One of the images was totally saturated,
       one was saturated in the corners opposite the pyramid corner, and
       the others were reported to be okay. 
 
   1.2 Completed FOS/RD 3647 (Star-Forming Histories of Elliptical Galaxies)
 
       The Faint Object Spectrograph was used to make five observations of
       the metallicity and age distribution of the hot stars in elliptical
       galaxy NGC-3610. All of the observations were received and
       displayed. They all were reported to be okay. 
 
   1.3 Uplinked Updated Ephemeris Tables ,Per MOSES 2871
 
       Uplinked at 336/0106Z.
 
   1.4 Completed WFC 1297 (GTO High Latitude Parallel Program)
 
       The Wide Field Camera was used to take two high latitude
       observations taken in parallel with the prime science observations.
       Both observations were received and displayed. They were reported to
       look okay. There were unusual looking bands across the images which
       were slightly darker than the background. They were still present
       after PODPS processed the images, so they are not flat field
       features. 
 
   1.5 Completed Two Sets of FOC/96 3747 (High Resolution Observations of 
       Cataclysmic Variables)
 
       The Faint Object Camera was used to make ultraviolet observations of
       the complex emission nebulosity surrounding cataclysmic variable
       star AG Pegasi. One observations was received and displayed. It was
       reported to be okay. A second observation still remains on the
       Science Tape Recorder and will be analyzed later. 
 
   1.6 Completed HSP/POL  2952 (X-Ray Binaries)
 
       The High Speed Photometer was used to measure the photometric and
       polarimetric light curves of the x-ray binary star Cygni X-1 (aka
       HDE226868). These observations are hoped to improve our
       understanding of the structure of this x-ray binary system. The
       observations were executed as scheduled, and no problems were
       reported. 
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 5
                                        Successful : 5
                          Scheduled Reacquisitions : 6
                                        Successful : 6
                                    Losses of Lock : 2
 
                           (335/1325Z, and 336/0709Z)
 
   2.2 FHST Updates: 
 
                              Scheduled : 8
                             Successful : 8
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: None
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Two Sets of HSP/POL 2952 (X-Ray Binaries)
 
   3.2 Complete Two Sets of FOC/96 3747 (High Resolution Observations of
       Cataclysmic Variables) 
 
   3.3 Complete WFC/PC 4109 (WF/PC Calibration: Rapid Internal Monitor)
 
   3.4 Complete Three Sets of PC 4714 (WF/PC Calibrations: PC Internal Delta
       Flats) 
 
   3.5 Complete Two Sets of WFC 4713 (WF/PC Calibration: WFC Internal Delta
       Flats) 
 
   3.6 Complete FOC/96 4107 (Search for QSOs Observations of He II 304 
       Absorption)
 
   3.7 Complete PC 4093 (Survey of the Markarian Galaxies)
 
   3.8 Complete PC 3230 (PC PSF and Focus Monitoring II)
 
   3.9 Complete GHRS/2 4227 (GHRS Return To Brightest (LSA) Test 2)
 
   3.10 Complete GHRS/2 4068 (GHRS Detector Calibrations)
 
   3.11 Initiate HSP/UV2/S/C 3798 (Search for Radial Pulsation in White Dwarfs)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS: 
 
       The First Servicing Mission Segment #1 Internal Simulations will be
       conducted on Wednesday Dec. 2, and Thursday Dec. 3. These
       simulations will provide the HST Servicing Mission team (FOT) with
       functional training to ensure operational readiness. The simulations
       will run approximately 12 hours each day. There are no planned test
       anomalies scheduled for these simulations. Support will be provided
       by Project Team, MOSES, ESA, PASSOPS, DOC, SPIF, and the HST
       Simulator. 
  
                                -END-
  

Article: 105
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: hst_status_12_04_92
Sender: [email protected] (USENET News System)
Organization: Space Telescope Science Institute
Date: Tue, 8 Dec 1992 19:54:43 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #778

Content-Length: 9034
X-Lines: 208
 
PERIOD COVERED:  0800 EST 12/04/92 - 0800 EST 12/07/92
 
Daily Status Report as of 342/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed FOS/BL 3791 ( Quasar Absorption Line Survey)
 
       The Faint Object Spectrograph was used to make observations of
       quasar PKS2251+11 to learn about its structure and evolution of gas
       distribution. It appeared as if the target was near the edge of the
       dwell scan, but the target was still successfully located. All of
       the following observations were reported to be okay. 
 
   1.2 Completed Six Sets of PC 4714 (WF/PC Calibration: PC Internal Delta
       Flats) 
 
       The Planetary Camera was used to take six sets of internal flat
       observations. The first five sets were monitored in the OSS, and no
       problems were reported. The last observation occurred during LOS and
       is still on the Science Tape Recorder. It will be reviewed later. 
 
   1.3 Completed PC 4163 (Formation and Evolution of Solar Nebulae)
 
       The Planetary Camera was used to take a series of five Earth flat
       observations which will be used later with observations of various
       protoplanetary nebulae. The observations were received and displayed.
       The first two, and the fourth flat were saturated. The others were
       reported to be okay. 
 
   1.4 Completed PC 4347 (WF/PC Calibration:Flood Retention Test)
 
       The Planetary Camera was used to obtain two Earth flat images using
       filter F439W, to determine how much of the last ultraviolet flood
       was still effective. One of the images was saturated, and the other
       was okay. 
 
   1.5 Completed Six sets of WFC 4713 (WF/PC Calibration : WFC Internal
       Delta Flats) 
 
       The Wide field Camera was used with 20 different filters to take
       internal flat observations. These are to be used in the restoration
       of Earth flats, which are altered due to changes in quantum
       efficiency which occurs after a WFPC decontamination operation. Five
       observations were received and displayed. four were reported to be
       okay, and one was saturated. 
 
   1.6 Completed FOC/96 4069 (Far Ultraviolet Spectra of Redshift Quasars)
 
       The Faint Object Spectrograph (f/96) was used to make objective
       prism spectral observations of high redshift quasar Q0302-003. The
       redshifted Lyman continuum was observed. The observation was
       executed in fine lock without problems. The core of the object were
       slightly elongated because the prism was in place. The point spread
       function was reported to slightly overlap the occultating finger. 
 
   1.7 Completed WFC 1297 (GTO High Latitude Parallel Program)
 
       The Wide Field Camera was used to make two high latitude
       observations in parallel with the prime science observations. Both
       image showed a few field stars in each chip, and a way-cool galaxy
       appeared in WF1. The observations were executed in fine lock. 
 
   1.8 Uplinked Updated Ephemeris Tables, per MOSES 2871.
 
       Uplinked at 340/0256Z, and 342/0225Z.
 
   1.9 Completed Two Sets of FOC/96 4107 (Search for QSOs Observation of He
       II 304 Absorption) 
 
       The Faint Object Camera (f/96) was used to attempt to image three
       different faint quasi-stellar objects. All three of the images were
       received and displayed. All of the images were reported to be blank. 
 
   1.10 Completed Two Sets of HSP/POL/UV2 2952 (X-Ray Binaries)
 
       The High Speed Photometer was used to measure the photometric and
       polarimetric light curves of the x-ray binary star Cygni X-1 (aka
       HDE226868). The first onboard target acquisition failed, and a 
       corrective SIP maneuver was uplinked to the spacecraft. There was an
       indication the the resultant observation was not centered. The OSS
       elected no to uplink another SIP. The next observation showed low
       counts and was reported to be bad.  The next onboard target
       acquisition left the target well centered,and the observations were
       received and displayed in the OSS. An HSTAR was filed on the failed
       binary search. 
 
   1.11 Completed FOC/96 4233 (FOC Point Spread Function f/96)
 
       The Faint Object Camera (f/96) was used to make two ultraviolet
       256X256 images of standard star BPM16274 to derive highly accurate
       point spread function images. Both images were taken in fine lock.
       The first image was somewhat overexposed. A corrective SIP
       maneuvered was uplinked. The second image was received and
       displayed. It was reported to look okay. 
 
   1.12 Completed WFC 3917 (HST Medium Deep Survey Part 1)
 
       The Wide Field Camera was used to take one high latitude image in
       parallel with the prime science observations. The observations was
       received and displayed in the OSS. The image was reported to be okay. 
 
   1.13 Completed WFC PC 4109 (WF/PC Calibration: Rapid Internal Monitor)
 
       Both the Wide Field Camera and the planetary camera was used to take
       two internal flat observations to check for different forms of
       contamination (i.e., daisies and measles). Both images were reported
       to look okay. 
 
   1.14 Completed PC 4140 (WF/PC Calibration: Rapid Internal Monitor Part 2)
 
       The Planetary Camera Was used to take two internal flat images to
       check for new forms of contamination. Both images were reported to
       be okay. 
 
   1.15 Completed FOS/BL 4057 (Spectropolarimetry of QSOs and Blazars)
 
          1.16 Completed WFC 4105 (HST Medium Deep Survey High Latitude)
 
       The Wide Field Camera was used to take one high latitude observation
       in parallel with the prime science observations. The image was
       reported to be okay, but nothing particularly interesting showed up. 
 
   1.17 Completed FOC/96 3790 (Polarization Imaging of radio Galaxies)
 
       The Faint Object Camera was used to take an ultraviolet polarization
       images of radio galaxy PKS1345+12. The observation was received and
       found to have a reduced exposure time due to a loss of fine lock. 
 
   1.18 Completed HSP/UV2 3255 (Search for Variability Associated with Black 
        Holes)
 
       The High Speed Photometer was used to make high rate ultraviolet
       photometry observations of the x-ray binary star A0620-00, who's
       companion is a suspected black hole. The target acquisition images
       were received and displayed. They showed nothing but noise. The next
       observations was lost since the TDRSS service was taken by the Space
       Shuttle, and the data was not written to the science tape recorder.
       The next observations was received and displayed and showed only
       noise, because the target acquisition failed. 
 
   1.19 Completed WFC 1306 (GTO Low Latitude Parallel Program)
 
       The Wide Field Camera was used to make low latitude observations in
       parallel with the prime science observations. The observations were
       executed as scheduled, and no problems were reported. 
 
   1.20 Completed HSP/VIS/S/C 3607 (Quasi-Periodic Oscillations in HM 
        Herculis Binaries)
 
       The High Speed Photometer was used to study high speed oscillations
       in binary system EF-Eridani. Three observations were taken in fine
       lock. The target was nearly centered in the second observation.
       During the third observation there was a loss of fine lock which
       appeared to interrupt the observation. This observation was filed as
       being bad. 
 
 2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 13
                                        Successful : 13
                          Scheduled Reacquisitions : 26
                                        Successful : 26
                                    Losses of Lock : 8
 
                               (339/2225,
                                340/0423, 0559,
                                341/0349, 0946, 1121, 1611, 1715Z)
                                  
   2.2 FHST Updates: 
 
                              Scheduled : 25
                             Successful : 25
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: None
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Two Sets of HSP/POL 2952 (X-Ray Binaries)
 
   3.2 Complete Five Sets of WFC 4713 (WF/PC Calibration: Internal Delta 
       Flats)
 
   3.3 Complete FOS/RD 3647 (Star Forming Histories of Elliptical Galaxies)
 
   3.4 Uplink Updated Ephemris Tables, Per MOSES 2871
 
   3.5 Complete WFC 1297 (GTO High Latitude Parallel Program)
 
   3.6 Complete Two Sets of FOC/96 (#&$& High resolution Observation of 
       Cataclysmic Variables)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS: Nothing at this time
 
                                -END-
 

Article: 106
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: hst_status_12_07_92
Sender: [email protected] (USENET News System)
Organization: Space Telescope Science Institute
Date: Thu, 10 Dec 1992 18:57:35 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #779
 
PERIOD COVERED:  0800 EST 12/07/92 - 0800 EST 12/08/92
 
Daily Status Report as of 343/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed Two Sets of FOS/BL 4204 (Spatially Resolves spectroscopy of 
       Saturn)
 
       The Faint Object Spectrograph was used to make ultraviolet spectral
       observations of Saturn's moon Tethys from 1500 to 3000 A0. The
       binary search and the acquisition image were reported to look okay.
       The three spectral science observations were okay. The third
       confirmation image of Tethys was well centered. 
 
   1.2 Completed PC 4163 (Formation and Evolution of Solar Nebulae)
 
       The Planetary Camera was used to take five Earth calibration images
       which will be used later to process images of protoplanetary
       nebulae. All five Earth flats were received and displayed. Two were
       underexposed, one was saturated, and the other two were okay. 
 
   1.3 Completed PC 3648 (Imaging of BL Lac Host Galaxies)
 
       The Planetary Camera was used to make eight images of BL Lac type
       object 1407+599 to measure its luminosity and determine the
       morphology of its nebulosity. The observations were executed in fine
       lock. All eight observations were reported to look okay. 
 
   1.4 Completed PC 3551 (Elliptical with Kinematically Distinct Nuclei)
 
       The Planetary Camera was used to obtain a pair of images of
       elliptical galaxy NGC-4589. Both observations were executed in fine
       lock. The images were received and displayed in the OSS. They were
       reported to look "nifty". 
 
   1.5 Completed PC 3799 (Imaging of Gravitational Lenses)
 
       The Planetary Camera was used to make images of gravitational lens
       candidate MG2016+112 to obtain data to aid in the characterization
       of the lensing systems. The observations were executed as scheduled,
       and no problems were reported. 
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 4
                                        Successful : 4
                          Scheduled Reacquisitions : 7
                                        Successful : 7
                                    Losses of Lock : 0
 
   2.2 FHST Updates: 
 
                              Scheduled : 8
                             Successful : 8
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: None
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Completed PC 3799 (Imaging of Gravitational Lenses)
 
   3.2 Complete FOS/RD 4112 (Evolution of Lyman Alpha And C IV Absorption 
       Study)
 
   3.3 Complete WFC-PC 4109 (Rapid Internal Monitor)
 
   3.4 Uplink Updated Ephemeris Tables, Per MOSES 2871.
 
   3.5 Complete PC 4748 (Imaging and Spec. of Near Earth Astroid)
 
   3.6 Complete FOC/96 4075 (Magellanic Cloud Planetary Nebulae)
 
   3.7 Complete PC 4163 (Formation and Evolution of Solar Nebulae)
 
   3.8 Complete S/C 4215 (FGS ITS Test)
 
   3.9 Complete PC 3551 (Elliptical with Kinematically Distinct Nuclei)
 
   3.10 Complete PC 4347 (Flood Retention Test)
 
   3.11 Initiate FOS/RD-BL 3791 (Quasar Absorption Line Survey)
 
   3.12 Initiate WFC 1306 (GTO Low Latitude Parallel Program)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS: Nothing at this time
 
                         -END-
 

Article: 107
Newsgroups: sci.astro.hubble
From: [email protected] (Ron Baalke)
Subject: WFPC-2 Will Magnify Hubble's Views of the Universe
Sender: [email protected] (USENET News System)
Organization: Jet Propulsion Laboratory
Date: Thu, 10 Dec 1992 19:01:49 GMT
 
>From the "JPL Universe"
December 4, 1992
 
JPL's new camera will magnify Hubble's views of the universe
By Diane Ainsworth
 
     Just weeks ago, the Hubble Space Telescope's all-purpose
"eyes" -- known as the Wide Field/Planetary Camera -- captured
the most detailed view ever of a galaxy's core, feeding a
suspected black hole in the Virgo cluster about 45 million light
years from Earth. 

     "The nucleus is probably the home of a black hole with a
mass 10 million times that of our sun," said Dr. Walter Jaffe of
the Leiden Observatory in the Netherlands, whose findings were
published in the Astrophysical Journal. "This is our best view to
date of the immediate surroundings of the nucleus of an active galaxy."

     While the performance of Hubble's Wide Field/Planetary
Camera-1 (WF/PC-1) has been hampered by a flaw in the curvature
of the telescope's primary mirror, the camera has nonetheless
produced some of the most awe-inspiring photographs of planets,
galaxies and exploding supernova ever taken. 

     Now JPL's new second-generation Wide Field/Planetary Camera
(WF/PC-2) -- scheduled for launch as part of the Hubble Space
Telescope's servicing mission next December -- is in final
assembly and promises even more spectacular views of distant
galaxies in the universe. The new camera has been designed to
correct the optical flaw in the Space Telescope's 95-inch
(2.4-meter or 8-foot) diameter primary mirror.  

     After installation, WF/PC-2, along with a second instrument
-- COSTAR, the Corrective Optics Space Telescope Axial
Replacement -- will restore the Hubble Telescope to its original
capabilities of imaging fine detail with high angular resolution,
photographing star clusters, detecting very faint stars, distant
galaxies and objects in the ultraviolet.     

     An innovative approach to correct the error in the primary
mirror was incorporated in the design of the new secondary
mirrors of the Wide Field/Planetary Camera relay optics, said
Larry Simmons, WF/PC-2 program manager at JPL.    

     "The WF/PC-2 incorporates optics that will internally
refocus the beam of incoming light from Hubble," he said. "We
corrected for the error in the curvature of the primary mirror by
creating an error of equal and opposite magnitude on the surfaces
of our WF/PC-2 relay optics. When the images reach the camera's
charge-coupled detectors (CCDs), the error will be reversed and
completely cancelled out."

     The Wide Field/Planetary Camera-2 actually consists of four
camera systems -- three wide-field cameras and one planetary camera.

     The wide-field cameras provide extraordinary sensitivity for
the detection of star clusters and distant galaxies, while the
planetary camera performs high-resolution studies of individual
objects, including planets and their moons, nearby galaxies and
other stellar objects. 

     As light enters the Hubble Space Telescope, it is bent at a
90-degree angle by a "pick-off" mirror and aimed into the Wide
Field/Planetary Camera. Design modifications in the new WF/PC
call for an adjustable pick-off mirror that ground technicians
will be able to tilt to align the light beam entering the camera.

     "The alignment of the pick-off mirror is critical to
correcting images," Simmons said. 

     The light beam passes through one of 48 filters before a
pyramid mirror inside the camera splits the light into four
quadrants. Each of the four quadrants of light is relayed by
tiny, nickel-size relay mirrors -- the mirrors that JPL modified
to correct for the error in the telescope's primary mirror -- to
a separate detector called a charge-coupled device (CCD). CCDs
collect light in the same way that film collects light in a
camera, but with much greater sensitivity.

     "The corrected images are formed on the CCD sensors,"
Simmons said. "The CCDs we are using in the new camera will have
greater sensitivity and will allow the camera to see from the
ultraviolet to the infrared."

     The new Wide Field/Planetary Camera and the COSTAR axial
replacement instrument will restore Hubble's imaging performance
to nearly 100 percent of the original specifications. Currently,
the telescope is able to focus only 10 to 15 percent of the light
it receives within a diameter of 0.2 arc-second. Its original
performance goal was to focus 70 percent of the light received.

     The telescope was designed to provide three basic
capabilities: high angular resolution -- the ability to image
fine detail; ultraviolet performance -- photographing ultraviolet
images and spectra; and high sensitivity -- the ability to detect
very faint stellar objects.

     With its corrective optics, scientists expect the telescope
will be able to provide the highest sensitivity to detect objects
10 times fainter than those visible from Earth-based telescopes,
with about 10 times greater spatial resolution.

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The 3 things that children 
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/  |_|/       |_____|/                     | space, dinosaurs and ghosts.
 

Article: 29629
Newsgroups: sci.astro
From: [email protected]
Subject: Toutatis with HST!
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Thu, 10 Dec 1992 22:29:27 GMT
 
This afternoon (Dec 10, around 18:30 UT) we got four images of asteroid
4179 Toutatis with the Planetary Camera of Hubble Space Telescope, at a
distance of about 0.029 AU and phase angle about 91 degrees.  An earlier 
attempt on Tuesday afternoon failed for technical reasons, and this was 
our last shot at it. 
 
Since the brightness was difficult to predict we took exposures of 6.0, 
2.3, 1.0, and 0.5 seconds in the visible-light filter (F555W).  The image
scale was 0.044 arcseconds or about 930 meters per pixel at the distance
of the object.  The first image was overexposed, and the second one 
saturated at the brightest pixel, but the other two were fine.  
 
This was HST project DD 4748, of which Keith Noll is PI and Alex Storrs, 
Hal Weaver, and I are co-investigators.  We cannot say what we saw until 
we do image deconvolution to correct for the spherical aberration.  I will 
post a summary as soon as we are ready to release any information. 
 
Other reports include visible photometry (lightcuves) and UBVRI by David 
Tholen at Mauna Kea and Peter Birch at Perth; thermal images in the 10-micron 
region at phase angles from 150 down to 92 degrees, by Jim Emerson colleagues 
at UKIRT on Mauna Kea; a successful UV spectrum with IUE this morning by 
Alan Stern et al; and truly splendid radar results by Steve Ostro at JPL. 
 
To my knowledge people at Tucson, Arizona and Merida, Venezuela should also 
be doing lightcurves, but I have not heard from either one.  The object is 
now rapidly moving away from the earth as it approaches opposition on Jan 18.  
It will continue to be accessible to groundbased observers into February. 
If you have a professional need-to-know about ongoing work, send e-mail to
John Spencer at [email protected] and he will be happy to add you to his 
distribution.
 
Ben Zellner
 
Article: 29663
Newsgroups: sci.astro
From: [email protected]
Subject: Toutatis with HST
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Fri, 11 Dec 1992 15:44:21 GMT
 
I neglected to list Art Whipple of the University of Texas as one of our
co-Investigators.  My apologies to Art
 
Ben
 

      Controllers are still investigating an anomaly involving a gyro, which
occurred November 18.  The spacecraft continues to operate and perform routine
science operations.  Initial telemetry indicated that the gyro lost
synchronization and motor current.  A later review of all monitors points to an
interruption of power to Gyro 1.  It has been commanded off for further study.
Candidate causes of the gyro anomaly include other anomalies within the control
electronics unit (such as a failed fuse).  An assessment of safely restarting
Gyro 1 is in progress.  Other actions being evaluated include 1) changes to HST
safemode configuration memory to remove access to Gyro 1, and 2) test and
activation of backup safemode software which increases vehicle protection when
in a three-gyro configuration.  Gyros 2,3, and 5 are operating normally.
Safemode will protect HST in the near term should another gyro failure or other
anomaly occur.  These gyros are part of HST's pointing control subsystem, which
maintains the spacecraft's positional stability and aligns the spacecraft to
point to an remain locked on any specific target.
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61

Paula Cleggett-Haleim
Headquarters, Washington, D.C.               December 16, 1992

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore

RELEASE:  92-226


     NASA's Hubble Space Telescope has uncovered the strongest evidence yet
that many stars may form planetary systems.

     Dr.  C. Robert O'Dell of Rice University, Houston, and colleagues have
used Hubble to discover extended disks of dust around 15 newly-formed stars in
the Orion Nebula starbirth region 1,500 light-years away.

     Such disks are a prerequisite for the formation of solar systems like
Earth's, according to astronomers.

     "These images provide the best evidence for planetary systems," said
O'Dell. "The disks are a missing link in our understanding of how planets like
those in our solar system form.  Their discovery establishes that the basic
material of planets exists around a large fraction of stars.  It is likely that
many of these stars will have planetary systems."

     Hubble Space Telescope's detailed images confirm more than a century of
speculation, conjecture and theory about the genesis of a solar system.

     According to current theories, the dust contained within the disks
eventually agglomerates to make planets.  Earth's solar system is considered a
relic of just such a disk of dust that accompanied the sun's birth 4.5 billion
years ago.

     Before the Hubble discovery, protoplanetary disks had been confirmed
around only four stars, Beta Pictoris, Alpha Lyrae, Alpha Piscis Austrini and
Epsilon Eridani.

     Unlike these previous observations, Hubble has observed newly formed stars
less than a million years old which are still contracting out of primordial
gas.

     Hubble's images provide direct evidence that dust surrounding a newborn
star has too much spin to be drawn into the collapsing star.  Instead, the
material spreads out into a broad, flattened disk.

     These young disks signify an entirely new class of object uncovered in the
universe, according to O'Dell.

     Hubble can see the disks because they are illuminated by the hottest stars
in the Orion Nebula, and some of them are seen in silhouette against the bright
nebula.  However, some of these protoplanets are bright enough to have been
seen previously as stars by ground-based optical and radio telescopes.  Their
true nature was not recognized until the Hubble discovery.

     Each protoplanet appears as a thick disk with a hole in the middle where
the cool star is located.  Radiation from nearby hot stars "boils off" material
from the disk's surface at a rate equal to about one-half the mass of Earth per
year.  This material is then blown back into a comet-like tail by a stellar
"wind" of radiation and subatomic particles streaming from nearby hot stars.

     Based on this erosion rate, O'Dell estimates that a protoplanet's initial
mass would be at least 15 times that of the giant planet Jupiter.

     Many of the youngest and hottest stars in the Milky Way Galaxy are found
in the Orion Nebula. The nebula is on the near edge of a giant molecular cloud
which lies immediately behind the stars that trace the sword of the
constellation Orion the Hunter.

     The region of Orion is a bright part of the nebula where stars are being
uncovered at the highest rate.  These results suggest that nearly half the 50
stars in this part of Orion have protoplanetary disks.

     O'Dell's co-investigators are graduate students Zheng Wen and Xi-Hai Hu of
Rice University and Dr. Jeff Hester of Arizona State University. Their results
will be published in the Astrophysical Journal next spring under the title
"Discovery of New Objects in the Orion Nebula on HST Images: Shocks, Compact
Sources and Protoplanetary Disks."
     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61

Article: 112
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: HST Status Report, 12/17 - 12/18
Sender: sah@wfpc3 (HST Newsgroup)
Organization: Space Telescope Science Institute
Date: Tue, 22 Dec 1992 15:15:57 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #787
 
PERIOD COVERED:  0800 EST 12/17/92 - 0800 EST 12/18/92
 
Daily Status Report as of 353/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Complete One Set of GHRS/2 3482 (Nature of In-Falling Matter on Star
       Beta Pictoris) and Initiate a Second.
 
       The High Resolution Spectrograph was used to take a series of 19
       ultraviolet spectral observations of the gaseous disk around Beta
       Pictoris (aka, HD39060) looking for cometary like objects which
       might be falling into the disk and being evaporated. The onboard
       target acquisition was successful. The wave calibrations looked
       okay, and all the spectral observations were reported to look good.
       A second set of observations are currently under way, and no
       problems have been reported. 
 
   1.2 Complete FOS/RD 3840 (Abundance of Carbon, Nitrogen, and Oxygen in ST)
 
       The Faint Object Spectrograph was used to make four ultraviolet
       spectral observations of the extra-galactic H II region IZW18. The
       binary search found the target in group eight, and looked okay.
       All of the spectral observations were reported to be okay. The
       second confirmation image also looked okay. 
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 2
                                        Successful : 2
                          Scheduled Reacquisitions : 9
                                        Successful : 9
                                    Losses of Lock : 0
 
   2.2 FHST Updates: 
 
                              Scheduled : 7
                             Successful : 7
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: 
 
       The First Servicing Mission Internal Simulation #2 was successfully
       completed yesterday, Thursday, Dec. 17. This simulation was intended
       to provided the HST Servicing Mission team with functional training
       to ensure operational readiness. This simulation went well and no
       major problems were reported. 
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Six Sets of GHRS/2 3482 (Nature and In-Falling of Matter
       on Star Beta Pictoris) 
 
   3.2 Uplink Updated Ephemeris Tables, Per MOSES 2871
 
   3.3 Complete PC 4093 (Survey of Nuclear Regions of Markarian Galaxies)
 
   3.4 Complete WFC/PC 4109 (WF/PC Calibration:Rapid Internal Monitor)
 
   3.5 Complete Two Sets of GHRS/2 4068 (GHRS Detector Calibrations)
 
   3.6 Complete PC 4140 (WF/PC Calibration: Rapid Internal Monitor Part 2)
 
   3.7 Complete PC 4163 (Evolution of Solar Nebulae Surrounding Pre-Main 
       Sequence)
 
   3.8 Complete GHRS/2 4065 (Dark Noise Monitoring HRS)
 
   3.9 Complete PC 3551 (Elliptical Galaxies with Kinematically Distinct 
       Nuclei)
 
   3.10 Complete FOC/96 4096 (Far Ultraviolet Spectra of High redshift 
       Quasars)
 
   3.11 Complete FOS/BL 3816 (White Dwarf Stars)
 
   3.12 Complete WFC 4105 (HST Medium Deep Survey,High Latitude)
 
   3.13 Complete WFC 4713 (Internal Delta Flats)
 
   3.14 Complete GHRS/2 2851 (Pulse Height Analysis (PHA))
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS: Nothing at this time
 
                          -END-
 
Article: 113
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: HST STATUS REPORT, 12/18 - 12/21
Sender: sah@wfpc3 (HST Newsgroup)
Organization: Space Telescope Science Institute
Date: Tue, 22 Dec 1992 15:17:27 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #788
 
PERIOD COVERED:  0800 EST 12/18/92 - 0800 EST 12/21/92
 
Daily Status Report as of 356/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed Six Sets of GHRS/2 3482 (Nature and In-Falling of Matter
       on Star Beta Pictoris) 
 
       The High Resolution Spectrograph was used to make ultraviolet
       observations of the gaseous disk around star Beta Pictouis (aka,
       HD39060) looking for cometary like objects which might be falling in
       to the disk and evaporating on contact. A total of 24 spectra were
       received and displayed. They were reported to be okay. Two
       observations did not occur because of GHRS carousel reset problems. 
 
   1.2 Uplinked Updated Ephemeris Tables, Per MOSES 2871
 
       Uplinked at 354/0102Z and 356/0057Z.
 
   1.3 Completed PC 4093 (Survey of Nuclear Regions of Markarian Galaxies)
 
       The Planetary Camera was used to take two images of two separate
       Markarian galaxies (MARK 382 and NGC-985) looking in their inner
       core regions and using filter F785LP. Both images were received and
       displayed in the OSS. Both images were reported to look okay. 
 
   1.4 Completed WFC/PC 4109 (WF/PC Calibration:Rapid Internal Monitor)
 
       Both the Planetary Camera and the Wide Field Camera were used to
       take internal flat observations which are checking for different
       forms of contamination (i.e., daisies and measles). The OSS
       monitored the observations and assessed the quality of the data. No
       problems were reported. 
 
   1.5 Completed Two Sets of GHRS/2 4068 (GHRS Detector Calibrations)
 
       The High Resolution Spectrograph was used to make internal flat
       calibration observations to check on the stability of the detectors.
       The observations were received and displayed. No problems were
       reported. 
 
   1.6 Completed PC 4140 (WF/PC Calibration: Rapid Internal Monitor Part 2) 
 
       The Planetary Camera was used to make two internal flat observations
       checking on new forms of contamination, and the reappearance of
       quantum efficiency hysteresis. Both images were received and
       displayed. They both were reported to look okay. 
 
   1.7 Completed PC 4163 (Evolution of Solar Nebulae Surrounding Pre-Main 
       Sequence)
 
       The Planetary camera was used to make internal Earth flat
       calibration images to be used later to process images of nebulae
       around pre-main sequence stars. Five images were received and
       displayed. Three images were reported to be saturated, one was
       underexposed, and one was reported to be okay. 
 
   1.8 Completed GHRS/2 4065 (Dark Noise Monitoring HRS)
 
       The High Resolution spectrograph was used to make internal dark
       observations to check on the levels of detector dark noise. The
       observations were executed as scheduled, and no problems were
       reported. 
 
   1.9 Completed PC 3551 (Elliptical Galaxies with Kinematically Distinct
       Nuclei) 
 
       The Planetary Camera was used to take two image of elliptical galaxy
       NGC-4494 looking at the stellar component of its nucleus. It is
       known to be kinematically distinct from the stars in the rest of the
       galaxy. Both observations were received and displayed. Both were
       reported to look okay. 
 
   1.10 Completed FOC/96 4096 (Far Ultraviolet Spectra of High redshift 
       Quasars)
 
       The Faint Object Camera (f/96) was used to obtain three ultraviolet
       objective prism images of high red shift quasar Q1451+124. All three
       images were received and displayed. It was noted that they all had a
       background level of around 7-10 counts, which is higher than usual. 
 
   1.11 Completed FOS/BL 3816 (White Dwarf Stars)
 
       The Faint Object Spectrograph was used to obtain spectral
       observations of white dwarf stars. Three observations were received
       and displayed. The first observations was a binary target
       acquisition, and had ten groups. The following two observations were
       reported to look okay. Shortly after the FOS came up to its final
       high voltage, a status buffer error message was received. It appears
       to be caused by a GIMP test. An HSTAR was written. 
 
   1.12 Completed WFC 4105 (HST Medium Deep Survey,High Latitude)
 
       The Wide Field Camera was used to take an image to be used for a
       high latitude survey. This image was taken in parallel with the
       prime science observations. It was received and displayed in the
       OSS. It was reported to look okay. 
 
   1.13 Completed WFC 4713 (Internal Delta Flats)
 
       The Wide Field Camera was used to make position measurements of the
       star Proxima Centauri to determine the presence of a Jupiter sized
       planet in orbit around the star. The observations were complete as
       scheduled, and no problems were reported. 
 
   1.14 Completed GHRS/2 2851 (Pulse Height Analysis (PHA))
 
       The High Resolution Spectrograph was used to make internal flat
       observations which will be used for the restoration of Earth flat
       images. These were altered due to changes in the quantum efficiency
       which occurred after WFPC decontamination operations. The
       observations were monitored in the OSS. No problems were reported. 
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 11
                                        Successful : 11
                          Scheduled Reacquisitions : 31
                                        Successful : 31
                                    Losses of Lock : 2
 
                                   (LOL at 355/1927, and 2104Z)
 
 
   2.2 FHST Updates: 
 
                              Scheduled : 21
                             Successful : 21
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: None
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete FGS 4031 (A Search for Planetary Companions to Low Mass)
 
   3.2 Complete Three Sets of PC 4714 (Internal Delta Flats)
 
   3.3 Complete GHRS/2 3964 (Dynamics and Energy Balance in Stellar 
       Regions)
 
   3.4 Complete FOC/96 3428 (High Voltage Turn On)
 
   3.5 Initiate GHRS/2 2536 (Deuterium in the Local Interstellar Gas)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       There will be a partial eclipse of the Sun at the end of Dec. 23 and
       the start of Dec. 24. This will effect two orbital passes of the
       Space Telescope, one orbit in each day. The First orbit will be
       effected for a 20 minute period, with a maximum of 37% reduction in
       Sun light. The second orbit will be effected for six minutes, with a
       2.4% reduction in Sun light. The Battery Rate of Charge Test will be
       disabled in the EPS System, and the Course Sun Sensors in the PCS
       System. 
 
       Due to the Christmas and New Years holidays no daily reports will be
       written on Thursday Dec. 24, Friday Dec. 25, and Friday Jan. 1. A
       daily report will be written Monday Through Thursday (Dec. 28 - Dec.31). 
 
                             -END-

Article: 114
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: HST STATUS REPORT, 12/21 - 12/22
Sender: sah@wfpc3 (HST Newsgroup)
Organization: Space Telescope Science Institute
Date: Mon, 28 Dec 1992 18:14:46 GMT
 
                           HUBBLE SPACE TELESCOPE
                               DAILY REPORT #789
 
PERIOD COVERED:  0800 EST 12/21/92 - 0800 EST 12/22/92
 
Daily Status Report as of 357/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed FGS 4031 (A Search for Planetary Companions to Low Mass)
 
       The Fine Guidance Sensors were used to measure the position of star
       Proxima Centauri relative to background reference stars. The intent 
       is to determine the presence of a Jupiter Sized planet in orbit
       around the target star. The observations were monitored by the OSS,
       and no problems were reported. 
 
   1.2 Completed Three Sets of PC 4714 (Internal Delta Flats)
 
       The Planetary Camera was used to take three different sets of
       internal delta flat images. All of the observations were received
       and displayed in the OSS. They all were reported to be okay. 
 
   1.3 Completed GHRS/2 3964 (Dynamics and Energy Balance in Stellar Regions)
 
       The High Resolution Spectrograph was used to observe the late type
       star HD61421 which is known to have plasma heated to temperature
       above 10,000 K above the photosphere. Four spectral observations
       were received and displayed. A wave length calibration image was
       also taken. A observations were reported to be okay. 
 
   1.4 Completed FOC/96 3428 (High Voltage Turn On)
 
       A standard high voltage turn on test was performed using the Faint
       Object Camera. Two internal flat, and one dark observations were
       taken. This was strictly an internal test. All of the observations
       were received and displayed. They all looked okay. 
 
   1.5 Initiated GHRS/2 2536 (Deuterium in the Local Interstellar Gas)
 
       The High Resolution Spectrograph's Echelle spectrograph was used to
       observe the interstellar absorption lines in the spectra of white
       dwarf star G191-B2B. A total of five observations have been
       completed , and a sixth observation has been initiated. The first
       two observations included two deflection calibrations, and spiral
       search, and peakup. the fifth observation was a calibration
       spectrum. The sixth observation is the spectral observation of the
       target star. 
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 3
                                        Successful : 3
                          Scheduled Reacquisitions : 9
                                        Successful : 9
                                    Losses of Lock : 1
 
                                   (LOL at 356/1312Z)
 
   2.2 FHST Updates: 
 
                              Scheduled : 5
                             Successful : 5
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: None
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete GHRS/2 2536 (Deuterium in the Local Interstellar Gas)
 
   3.2 Complete Two Sets of PC 4714 (Internal Delta Flats)
 
   3.3 Complete Two Sets of S/C 4215 (FGS ITS Test)
 
   3.4 Uplink Updated Ephemeris Tables, Per MOSES 2871
 
   3.5 Complete FOS/RD 3816 (White Dwarf Stars)
 
   3.6 Complete PC 4106 (HST Medium Deep Survey: Low Latitude)
 
   3.7 Complete WFC-PC 4109 (Rapid Internal Monitor)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS: Nothing at this time
 
                                -END-
 
Article: 115
Newsgroups: sci.astro.hubble
From: [email protected]
Subject: HST STATUS REPORT, 12/22 - 12/23
Sender: sah@wfpc3 (HST Newsgroup)
Organization: Space Telescope Science Institute
Date: Mon, 28 Dec 1992 18:18:36 GMT
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #790
 
PERIOD COVERED:  0800 EST 12/22/92 - 0800 EST 12/23/92
 
Daily Status Report as of 358/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed GHRS/2 2536 (Deuterium in the Local Interstellar Gas)
 
       The High Resolution Spectrograph used its Echelle spectrograph
       to make observations of interstellar absorption lines in the spectra
       of white dwarf star G191-B2B. The first four observations were: two
       deflection calibrations, a spiral search, and the peakup. There were 15
       spectral observations which followed. All of the observations were
       made in course track, and all were reported to be okay. 
 
   1.2 Completed Two Sets of PC 4714 (Internal Delta Flats)
 
       A total of nine internal flat observations were made with the
       Planetary Camera. These images will be used for the restoration of
       Earth flats, which are altered due to the changes in quantum
       efficiency which occur after a WFPC decontamination operations. All
       of the internal flats were received and displayed. They were all okay. 
 
   1.3 Completed Two Sets of S/C 4215 (FGS ITS Test)
 
       The Fine Guidance Sensor internal test was executed as scheduled,
       and no problems were reported. 
 
   1.4 Uplinked Updated Ephemeris Tables, Per MOSES 2871
 
       Uplinked at 358/0100Z.
 
   1.5 Completed FOS/RD 3816 (White Dwarf Stars)
 
       The Faint object Spectrograph was used to obtain spectral
       observations of white dwarf star L151-81. The onboard target
       acquisition was successful. The OSS monitored the first spectral
       observation, and it was successful. The other observations occurred
       during LOS, and still are on the science tape recorder. 
 
   1.6 Completed PC 4106 (HST Medium Deep Survey: Low Latitude)
 
       The Planetary Camera was used to make low latitude observations in
       parallel with the prime science observations. This is to provide for
       serendipitous discoveries and data for a basic sky survey. The
       observations were monitored in the OSS, and no problems were
       reported. 
 
   1.7 Completed WFC-PC 4109 (Rapid Internal Monitor)
 
       Both the Wide Field Camera and the Planetary Camera were used to
       obtain internal flat observations using filter F555W. This operation
       is to check for different forms of contamination (i.e., daises and
       measles). The internal flat observations were monitored in the OSS,
       and no problems were reported. 
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 1
                                        Successful : 1
                          Scheduled Reacquisitions : 7
                                        Successful : 7
                                    Losses of Lock : 0
 
   2.2 FHST Updates: 
 
                              Scheduled : 7
                             Successful : 7
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Note: None
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Two Sets of GHRS 2536 (Deuterium in the Local Interstellar
       Gas) 
 
   3.2 Complete Two Sets of PC 3912 (Cores of Early Type Galaxies)
 
   3.3 Complete FOS/BL 3939 (Lyman Alpha Regions in QSOs)
 
   3.4 Complete HSP/UV2 1099 (Active Galactic Nuclei)
 
   3.5 Complete Uplink Updated Ephemeris Tables, Per MOSES 2871
 
   3.6 Complete Two Sets of FGS 3688 (Diagnostic of Early Type Stellar
       Evolution) 
 
   3.7 Complete HSP/UV1-PC 4741 (Orbital Effects Test Calibration)
 
   3.8 Complete One Set of FOS/RD 3816 (White Dwarf Stars) and Initiate a 
       Second.
 
   3.9 Complete PC 4106 (HST Medium Deep Survey: Low Latitude)
 
   3.10 Complete PC 4347 (Flood Retention Test)
 
   3.11 Complete FOS/RD 3566 (Do Galaxies Produce Absorption Lines)
 
   3.12 Complete WFC 4105 (HST Medium Deep Survey: High Latitude)
 
   3.13 Complete PC 4712 (Measles Monitor)
 
   3.14 Complete HSP/UV1 3257 (Periodic Variations in DQ Herculis Stars)
 
   3.15 Complete PC 3657 (The Host Galaxies of the BL Lacertea Objects)
 
   3.16 Complete PC 4349 (Black Holes, Stellar Dynamics and Populations)
 
   3.17 Complete PC 4140 (Rapid Internal Monitor - Part 2)
 
   3.18 Complete PC 3286 (Nuclei of Nearly Normal Galaxies)
 
   3.19 Complete FOC/96 4107 (Search for QSOs Suitable for Subsequent 
        Observations)
 
   3.20 Complete WFC-PC 4109 (Rapid Internal Monitor)
 
   3.21 Complete S/C 4215 (FGS ITS Test)
 
   3.22 Complete HRS/2 4065 (Dark Noise Monitoring)
 
   3.23 Complete FOC/96 3504 (Resolution Imaging and Spectroscopy of AGN)
 
   3.24 Complete WFC 2227 (Determination of Extra-galactic Distance Scale:
        M-81) 
 
   3.25 Complete GHRS/2 3706 (Nature of Gaseous Loops in the Milky Way Halo)
 
4.0 ANOMALY STATUS:
	
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
 
 5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       There will be a partial eclipse of the Sun at the end of Dec. 23
       (today) and the start of Dec. 24 (tomorrow). This will effect two
       orbital passes of the Space Telescope, one orbit in each day. The
       First orbit will be effected for a 20 minute period, with a maximum
       of 37% reduction in Sun light. The second orbit will be effected for
       six minutes, with a 2.4% reduction in Sun light. The Battery Rate of
       Charge Test will be disabled in the EPS System, and the Course Sun
       Sensors in the PCS System. 
 
       Due to the Christmas and New Years holidays no daily reports will be
       written on Thursday Dec. 24, Friday Dec. 25, and Friday Jan. 1. A
       daily report will be written Monday Through Thursday (Dec. 28 - Dec.
       31). 
 

Paula Cleggett-Haleim
Headquarters, Washington, D.C.               January 7, 1993

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore

RELEASE:  93-006


     Astronomers, using the Hubble Space Telescope, now
believe that a galaxy they have observed for a decade
actually is composed of two merged galaxies and that the
collision has provided new fuel for a massive black hole
which is spewing out a jet of gas and other matter 240,000
light-years long.

     The galaxy is Markarian 315 located about 500 million
light-years from Earth.  The collision and refueling theory
emerged after the Hubble Telescope revealed that the galaxy
has a double nucleus or two core-like regions.

     The brighter core-like region is believed to harbor the
massive black hole which accounts for the tremendous amounts
of energy produced by the galaxy.  The fainter nucleus is
considered to be the surviving core of a galaxy that recently
merged into Markarian 315.

     "The galaxy's active core presumably harbors a black
hole which has been re-fueled by the galactic collision,"
said Dr. Jack MacKenty, Assistant Scientist at the Space
Telescope Science Institute in Baltimore.

     "The Hubble images provide support for the theory that
the jet-like feature may be a 'tail' of gas stretched out by
tidal forces between the two galaxies as they interacted,"
explained Dr. MacKenty, Assistant Scientist at the Space
Telescope Science Institute.

     "The jet feature is most likely a remnant of a merger
between Markarian 315 and a smaller galaxy," said MacKenty.
This observation best explains the extraordinary 240,000-
light-year long jet-like feature of Markarian 315.

     An image of the core of Markarian 315, taken with the
Hubble Space Telescope's Wide Field and Planetary Camera
shows a second, fainter nucleus located approximately 6,000
light-years (or 2 arc seconds in angular separation) from the
galaxy's bright central nucleus.  One light-year equals
approximately 5.8 trillion miles (9.3 trillion km).

     Galaxy mergers may be one mechanism for driving gas deep
into the heart of a galaxy, astronomers believe.  This raw
material fuels massive black holes, theorized to be the
"central engines" in Seyfert galaxies and other active
galaxies.

     The Hubble Space Telescope's high spatial resolution
allows astronomers to probe the cores of Seyfert galaxies in
unprecedented detail.  In exposures taken with ground-based
telescopes, the companion nucleus is drowned out by the
brighter Seyfert nucleus.

     The report on this discovery is by Drs. John MacKenty
and Andrew Wilson of the Space Telescope Science Institute,
Baltimore; Richard Griffiths of The Johns Hopkins University,
Baltimore; and Susan Simkin of Michigan State University,
East Lansing.  The report was delivered at the 181st Meeting
of the American Astronomical Society meeting in Phoenix,
Ariz.

     The Hubble Space Telescope is a project of international
cooperation between NASA and the European Space Agency.

     Source:NASA Spacelink    Modem:205-895-0028  Internet:192.149.89.61
=

Article: 3244
Newsgroups: sci.space.news
From: [email protected] (Ron Baalke)
Subject: Building WF/PC-2
Sender: [email protected]
Organization: Jet Propulsion Laboratory
Date: Fri, 12 Mar 1993 16:12:00 GMT
 
From the "JPL Universe"
March 12, 1993
 
Bold measures result in quick turnaround for design,
building of WF/PC-2's mirrors.
 
By Diane Ainsworth
 
     When push came to shove in December 1991, and JPL's Dr.
James Fanson was asked to investigate the feasibility of building
three moveable fold mirrors for the new Wide Field/Planetary
Camera, he decided to go for broke.

     "There was no tried-and-true way to solve the problem we had
discovered with the Hubble Telescope's primary mirror," he said.
"We discovered that correcting the imaging performance of the
Hubble would require 10 times more precise optical alignment than
it did for the WF/PC-1 camera. So we set out to build a set of
articulating fold mirrors inside the camera that we could adjust
from the ground to realign images.

     "We were up against the tightest deadline we've ever had,"
Fanson said. "We needed to design and build the articulating
mirrors in less than 10 months, and we had to build the control
electronics in less time than it normally takes just to procure
the parts!

     "But JPL took some bold measures to ensure that our work was
high priority, and every procedure was completed as quickly as
possible," he said. "If ever there were a case-in-point of JPL's
ability to build something faster, better and cheaper, this was it."

     Fanson assembled a team of the best talent at JPL, and they
hit the ground running.

     "We quickly realized that to meet the performance
requirements for these new mirrors, we needed to use new
technology ceramic actuators, which were developed by Litton/Itek
Optical Systems for the Department of Defense," he said. "The JPL
procurement people got Itek on contract with us in less than four weeks."

     Fanson and his team next identified the solution that would
correct and bring images into focus from the Hubble Telescope's
8-foot-diameter (2.4-meter) primary mirror.

     "Basically what's going on inside the camera is that we're
canceling the error in the Hubble primary mirror with a matching
error intentionally polished onto a mirror in WF/PC-2," he said.
"This cancellation is straightforward in theory, but is made
difficult in practice because of the large magnitude of the
error. It's like trying to subtract a large number from another
large number and coming up with zero.  This only works if the
Hubble is exactly aligned with WF/PC-2, and that's the job of the
new articulating fold mirrors."

     Light entering the camera is split into four quadrants by
the pyramid mirror before reaching the relay secondary mirror.
The newly shaped secondary mirror, which is the size of a dime,
is where the cancellation of the Hubble error actually occurs.
Light then continues on to the camera's charge-coupled devices
(CCDs), where the image is formed.

     Fanson, along with Bob Bamford and Paul MacNeal of the
Applied Technologies Section 354, decided that they would have to
replace the "fixed" -- unmoveable -- fold mirrors in the camera
with articulated, adjustable mirrors that could be tipped and
tilted to make sure the light beam fell precisely in the middle
of the secondary relay mirrors. Not only would that alignment
capability be necessary after the vibrations and jitters of
launch and installation, Fanson said, but it would be a means of
guaranteeing on-orbit alignment in later months.

     "The trick was to come up with a design that would fit in a
very tiny space, less than nine-tenths of an inch thick and 1.6
inches in diameter," he said.  "The parts are so small that they
were assembled under a microscope." Designing the assembly
tooling and procedures was the responsibility of Al Delgadillo of
the Mechanical Systems Development Section 352.

     Changes in mirror position are accomplished by each mirror's
tilt mechanism, which is like a three-legged stool, Fanson
explained. The legs are composed of tiny ceramic actuators that
lengthen when a voltage is applied to them.

     "By controlling the lengths of the three legs, we can
control the tip and tilt of the mirror," Fanson said. "We are
talking about very small motions -- the total stroke of the
actuators is equal to the length your hair grows in 15 minutes."

     The amount of voltage applied to the actuators is programmed
by computers at the ground operations facility at Goddard Space
Flight Center in Greenbelt, Md.

     After assembly at JPL and Itek, the mirrors went through
environmental testing. When specifications were met, they were
delivered to the WF/PC-2 integration and test team in early July
-- with two days to spare in the schedule. Meanwhile, Tom Radey
of the Imaging Systems Section 381 was busy building an extremely
stable set of control electronics to command the 18 actuators in
the three articulating mirrors.

     "We made it in the nick of time, but we made it," said
Fanson, who was awarded a 1992 Lew Allen Award for the articulating 
fold mirror effort. "We came in under budget and on time."

     Launch of the Hubble Space Telescope servicing mission,
STS-61, is tentatively scheduled for Dec. 2, 1993, aboard the
space shuttle Endeavour. Installation of the new Wide
Field/Planetary Camera will occur on the second day of astronaut
extra-vehicular activities (EVA), said Michael Devirian, WF/PC-2
deputy program manager and head of servicing and operations.

     Adjustments to the camera and other instruments will take
about a month, Devirian said. Ground-controllers will have to
wait three weeks before they can turn on the coolers to bring the
camera sensors down to about minus 80 degrees Celsius (about
minus 112 degrees Fahrenheit). Then they will begin taking
photographs, analyzing the images and fine-tuning the new
articulating fold mirrors.

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | It's kind of fun to do
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | the impossible. 
|_____|/  |_|/       |_____|/                     | Walt Disney
 

Article 3542 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: HST Servicing Mission Scheduled for 11 Days
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41    
Keywords: HST
Sender: [email protected]
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Organization: Jet Propulsion Laboratory
Date: Fri, 23 Apr 1993 16:41:00 GMT
Approved: [email protected]
Lines: 88

Ed Campion
Headquarters, Washington, D.C.                             April 23, 1993
(Phone:  202/358-1780)

Kyle Herring
Johnson Space Center, Houston
(Phone:  713/483-5111)

RELEASE:  93-76

HUBBLE TELESCOPE SERVICING MISSION SCHEDULED FOR ELEVEN DAYS

	The December flight of Endeavour on Space Shuttle mission STS-61 to
service the Hubble Space Telescope (HST) has been scheduled as an 11 day
mission designed to accommodate a record five spacewalks with the capability
for an additional two, if needed.

	The decision to schedule five extravehicular activities, or EVAs, was
reached following extensive evaluations of underwater training, maneuver times
required using the Shuttle's robot arm based on software simulations and actual
EVA tasks on previous missions.

	"Basically what we've done by going to five EVAs rather than three is
to repackage our margin so that we have the capability to respond to the
dynamics, or unknowns, of spacewalks," Mission Director Randy Brinkley said.
"It improves the probabilities for mission success while providing added
flexibility and adaptability for reacting to real-time situations."

	In laying out the specific tasks to be completed on each of the
spacewalks, officials have determined that changing out the gyros, solar arrays
and the Wide Field/Planetary Camera (WF/PC) and installing the Corrective
Optics Space Telescope Axial Replacement (COSTAR) are priority objectives
during the mission.

	"When we looked at accomplishing all of the tasks, highest through
lowest priority, and recognizing that the major tasks -- gyros, solar arrays,
WF/PC and COSTAR -- would consume most of the time set aside for each
spacewalk, five EVAs were deemed appropriate," said Milt Heflin, Lead Flight
Director for the mission.

	While the five spacewalks will be unprecedented, the use of two
alternating spacewalk teams will alleviate placing more stress on the crew than
previous missions requiring two, three or four EVAs.

	"We have paid close attention to lessons learned during previous
spacewalks and factored these into our timeline estimates for five EVAs,"
Heflin said.  "In planning for all Space Shuttle missions, it is necessary to
formulate a work schedule that represents as realistic a timeline as possible
to accomplish the mission objectives."

	Planning currently calls for at least five water tank training sessions
that include support from the Mission Control Center, called joint integrated
simulations, lasting between 10 and 36 hours.  In addition, many stand alone
underwater training "runs" will practice individual tasks in each spacewalk.

	Various refinements to the specific tasks on each spacewalk will be
made based on actual training experience during the months prior to the
mission.  Also, lessons learned from other spacewalks leading up to the flight
will be valuable in assisting the STS-61 crew in its training techniques.

	Endeavour's June flight and Discovery's July mission both will include
spacewalks to evaluate some of the unique tools to be used on the HST mission.
The evaluations will help in better understanding the differences between the
actual weightlessness of space and the ground training in the water tanks at
the Johnson Space Center, Houston, and the Marshall Space Flight Center,
Huntsville, Ala.

	Also, the inflight spacewalking experiences will assist in gaining
further insight into the time required for the various tasks and expand the
experience levels among the astronaut corps, the flight controllers and
trainers.

	Designed to be serviced by a Space Shuttle crew, Hubble was built with
grapple fixtures and handholds to assist in the capture and repair procedures.

	The telescope was launched aboard Discovery in April 1990.  At that
time the NASA mixed fleet manifest showed the first revisit mission to HST in
1993 to change out science instruments and make any repairs that may have
become necessary.

- end -
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The aweto from New Zealand
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | is part caterpillar and
|_____|/  |_|/       |_____|/                     | part vegetable.

Mark Hess/Jim Cast
Headquarters, Washington, D.C.          May 25, 1993


RELEASE:  93-96

        A task force established by NASA Administrator Daniel S. Goldin to
review plans for the Hubble Space Telescope servicing mission concluded that,
"the mission is achievable." This conclusion was driven by the fact that the
spacecraft and most of its subsystems were designed for on-orbit maintenance.

        The Task Force on the Hubble Space Telescope Servicing Mission,
chartered in late January, reviewed all aspects of the first servicing mission
which is currently scheduled for December 1993.  Dr. Joseph F. Shea was
Chairman of the task force.

        "We were asked to arrive at a judgement as to the likelihood of success
of the repair and servicing mission," said Shea. "In our opinion, we think the
mission is achievable."

        The task force pointed out, however, that the mission is complex and
will require more EVA (spacewalk) time than any mission to date.  Given this
complexity, the task force recommended that a second HST servicing mission be
planned 6 to 12 months after the STS-61 flight to handle tasks that might not
be completed during the first mission or respond to failures that occur in the
intervening months.

        Shea said planning and management changes, which have taken place over
the past few months, will improve the likelihood of success. "We support the
appointment of a Mission Director, and believe that such a position, with
authority and resources, is necessary if the mission is to be carried out with
confidence," Shea said.

        The task force report also concluded that a full end-to-end simulation
of the EVA in the Neutral Buoyancy Simulator at the Marshall Space Flight
Center, Huntsville, Ala., which is currently in the planning stage, is
"essential to a successful mission."

        "There are some areas, like schedule, where we still have some
concerns," Shea said. "We think the timelines for the EVAs are very tight and
some of the hardware is not fully assembled.  But we were very pleased to see
that NASA extended the mission duration and the number of EVAs for the flight."

  

Paula Cleggett-Haleim
Headquarters, Washington, D.C.

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.


RELEASE:  93-97

        NASA's Hubble Space Telescope has looked into the heart of a galaxy
created by the collision of two galaxies and peering deeply into its nucleus,
discovered a remarkable pinwheel-shaped disk of gas surrounded by clusters of
young stars born as a result of the merger.

        The star clusters apparently were born as a result of the collision of
two disk-shaped galaxies.  The galaxy merger, which occurred about 1 billion
years ago, triggered an infall of the gas which fueled the birth of new stars
around the center of the galaxy.

        "This may unlock the key for understanding how all globular clusters
formed in ellipticals," said Dr. Brad Whitmore of the Space Telescope Science
Institute (STScI), Baltimore, Md. "The Hubble observation also shows how tiny
disk-like structures might have formed in many other galaxies."

        This discovery provides some of the best evidence to date for
explaining the origin of giant elliptical galaxies.  For more than a half
century, astronomers have theorized about how such galaxies formed.  Some
theories propose that ellipticals formed from collisions between disk galaxies
-- flattened stellar systems resembling the Milky Way galaxy.

        These results are being presented in a press conference today at NASA
Headquarters, Washington, D.C., by Whitmore and Dr. Francois Schweizer of the
Carnegie Institution of Washington. Co-investigators are Claus Leitherer, Kirk
Borne and Carmelle Robert of STScI.



Pinwheel of Stars and Gas

        The striking Hubble image shows a spiral pattern at the galaxy's core,
surrounded by bright star clusters. "I knew I had a major result within 10
seconds of looking at the Hubble picture," said Whitmore.

        The pinwheel shaped disk has an uncanny resemblance to a face-on spiral
galaxy, yet it is only 10 thousand light-years across -- about 1/20 the size of
the total galaxy.  The gas and stars in the disk swirl around the nucleus,
making a spiral pattern like cream poured in a cup of coffee.  The mini-spiral
contains enough gas to make 8 billion stars like the sun.  Though several of
the clusters were first spotted from ground- based telescopes, their true
nature was uncertain until the Hubble observations.

        Hubble's resolution is so good that the astronomers can measure the
diameters (0.04 arc seconds, the apparent size of a dime at a distance of 80
miles) of the bright star clusters seen in the same image as the spiral disk.
They turn out to be about 60 light years across, the same size as globular
clusters that orbit the Milky Way galaxy.

        The globular clusters found in NGC 7252 are considered the progenitors
of similar clusters that orbit the Milky Way galaxy.  Since globular clusters
normally contain ancient red giant stars, they provide a fossil record of the
formation and evolution of galaxies.  Globular clusters contain about 1 million
stars each, arranged in a tight, spherical swarm and generally are found to be
about 15 billion years old.

        However, the "ultra-luminous clusters" found in NGC 7252 contain hot
bluish stars.  Because these blue stars are short-lived, the clusters in NGC
7252 are estimated to be mostly between 50 and 500 million years old.

        The blue stars make the globular clusters up to several hundred times
brighter than the clusters that orbit the Milky Way galaxy.  If the Milky Way's
globular clusters were as bright, they could be seen with the naked-eye and
would be brighter than the stars in the Big Dipper.

        In the 1920's, American astronomer Edwin Hubble classified galaxies
according to their spiral or elliptical shape.  A key difference is that stars
are concentrated in a disk in spirals, but are distributed in a diffuse,
roughly spherical distribution in ellipticals.

        Since Edwin Hubble's time, astronomers have sought an explanation for
why there are two different types of galaxies.  During the past decade, the
hypothesis that spiral galaxies can collide and merge to form elliptical
galaxies has become increasingly popular.




        Located 300 million light-years away in the constellation Aquarius, NGC
7252 has been considered the prototypical example of a merger between two
disk-shaped galaxies.  The galaxy has a pair of long tails that are unambiguous
evidence of the effects of gravitational tidal forces from a galaxy merger.

        The galaxy NGC 7252 is nicknamed the "Atoms-for-Peace" galaxy because
its stars form a bizarre loop-like structure that resembles a schematic diagram
of an electron orbiting and an atomic nucleus. (In December 1953.  U.S.
President Dwight D. Eisenhower made his "Atoms for Peace" speech to foster
peaceful applications of nuclear energy.

        If globular clusters can be born during galaxy collisions, it
reinforces the theory that disk galaxies merge to make giant elliptical
galaxies.  One argument against this theory is that elliptical galaxies have
more globular clusters than expected if disk galaxies were simply combined,
since disk galaxies have relatively few clusters.

Hubble Picture Helps to Solve Mystery

        The new Hubble Space Telescope observation solves this dilemma by
showing that when disk galaxies collide they can form new globular clusters.
Rather than being a problem for the merger scenario, an increase in the number
of globular clusters is a natural consequence of galaxy mergers.

        The existence of a "mini-disk" also fits with the merger scenario since
similar disk-like features appear to exist in many elliptical galaxies.
Another clear indication that the material originated from the collision of two
galaxies is that the mini-spiral is rotating in a direction opposite to the
rest of the galaxy.

        This discovery is the latest in a series of disk-like structures that
Hubble has uncovered at the cores of galaxies.  Previously, HST found a giant
disk of cool dust and gas orbiting a suspected black hole in the active galaxy
NGC 4261 and discovered an edge-on "donut" of dust in the spiral galaxy M51.

        The astronomers predict that in a few billion years the gas in NGC 7252
will be exhausted.  The galaxy will look like a normal elliptical galaxy with a
small inner disk.

Article 3895 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: WFPC-2 Shipped
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41    
Keywords: WFPC-2, JPL
Sender: [email protected]
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Wed, 2 Jun 1993 17:37:00 GMT
Approved: [email protected]
Lines: 70

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

Contact: Diane Ainsworth

FOR IMMEDIATE RELEASE                              June 2, 1993
JPL Press Release #1511

     The Jet Propulsion Laboratory's new Wide Field/Planetary
Camera, designed to replace the current camera on board NASA's
orbiting Hubble Space Telescope, was shipped yesterday from JPL,
two years after major redesign changes began in August 1991.  
     The camera will be delivered to the Goddard Space Flight
Center in Greenbelt, Md., where it will be tested with spacecraft
and ground system simulators before being shipped to Kennedy
Space Center in Florida for integration with the space shuttle,
said Larry Simmons, WF/PC-2 program manager at JPL.
     "The Wide Field/Planetary Camera-2 was designed to restore
nearly all of the original imaging capability lost when an
optical flaw was discovered in the Hubble telescope's primary
mirror," Simmons said.  "We modified the camera's internal relay
optics and made several other design changes to enhance WF/PC-2's
overall imaging capability."
     Four small relay mirrors inside the camera's four optical
trains have been polished to a new prescription that will cancel
the error in the curvature of the Hubble Space Telescope's
primary mirror by creating an error of equal and opposite
magnitude, Simmons said.
     Small actuators will fine-tune the alignment of these
mirrors on orbit, assuring the optical quality that will be
required to image fine detail in star clusters, distant galaxies
and objects in the ultraviolet.
     After the camera has been tested at Goddard, it will be
delivered in mid-September to Kennedy Space Center, where it will
be readied for a Dec. 2, 1993 launch aboard the space shuttle
Endeavour.     
     The camera is scheduled to be installed on the orbiting
telescope on the third day of astronaut extravehicular activities
during STS-61, the first of several Hubble Space Telescope
servicing missions designed to replace major components of the
space telescope and science instruments. 
     About one month after installation, the new camera will be
ready to begin imaging science targets with its three wide-field
camera systems and one planetary camera system.  The wide-field
cameras will provide extraordinary sensitivity for the detection
of star clusters and distant galaxies, while the planetary camera
will perform high-resolution studies of individual objects,
including planets and their satellites, nearby galaxies and other
stellar objects.    
     WF/PC-2 will be able to detect objects 100 times fainter
than those visible from Earth-based telescopes, with about 10
times greater spatial resolution.  The camera also has the unique
capability of imaging in the far ultraviolet, a capability that
is impossible from ground-based telescopes and limited, at best,
from space.    
     The Wide Field/Planetary Camera-2 was designed and built by
the California Institute of Technology's Jet Propulsion
Laboratory for NASA's Office of Space Science.
                              #####
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

Article 3956 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: Hubble Closes In On Age of the Universe
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
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Keywords: HST
Sender: [email protected]
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Paula Cleggett-Haleim
Headquarters, Washington, D.C.                      June 9, 1993
(Phone:  202/358-0883)            

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)

RELEASE:  93-108

HUBBLE CLOSING IN ON AGE OF THE UNIVERSE

     Astronomers working with NASA's Hubble Space Telescope today
announced results of a major step to measure the Hubble Constant
and the age of the universe.

     The team has discovered Cepheid (variable) stars in its
first target, the spiral galaxy M81, and measured the distance of
the galaxy to be 11 million light years.  They quote a 10 percent
uncertainty in this result (plus or minus approximately one
million light years).  Previous estimates of the galaxy's
distance have ranged from 4.5 to 18 million light years.

     Cepheids are pulsating stars that become alternately
brighter and fainter with periods ranging from 10 to 50 days.
Astronomers have known for over 50 years that the periods of
these stars precisely predict their total luminous power, which
allows their distance to be measured.

     The Hubble Constant (H0) is the ratio of the recession
velocities of galaxies to their distances in the expanding
universe.  The age of the universe can be estimated from the
Hubble Constant and currently is thought to lie between 10 and 20
billion years.  A more precise measurement of the Hubble Constant
is required to narrow this range.

     Team member Dr. Wendy Freedman of Carnegie Institution of
Washington said, "In our two observed fields in M81, we have
found a total of 32 Cepheids.  Decades of previous work from the
largest ground-based telescopes have only succeeded in measuring
periods for two Cepheids.  HST's superior resolution and its
ability to schedule observations when and where they are required
give HST a special advantage in this work."

     Messier 81 is a large spiral galaxy in the constellation
Ursa Major.  It is a rotating system of gas and stars similar to
the Milky Way galaxy, but approximately twice as massive.  This
galaxy achieved prominence 3 months ago when the brightest
northern supernova of this century was discovered.

     The astronomers used the Hubble's Wide Field & Planetary
Camera to study two fields in M81.  In each field they took 22
20-minute exposures spread over 14 months to find the variable
stars and measure their periods and brightness.

      The project is one of several so-called "key projects"
designated top priority scientific goals for the Hubble Space
Telescope.  This extragalactic distance scale key project aims to
discover Cepheids and measure the distances to galaxies to
determine an accurate value of the Hubble Constant.

      Dr. Jeremy Mould, Principal Investigator for the team,
said, "This is the first step in a major program of measuring
distances of galaxies with the Hubble Space Telescope.  When the
telescope is serviced later this year, and the new Wide Field &
Planetary Camera is installed with its corrective optics, we plan
to use the same technique on galaxies up to 50 million light
years away, which will allow us to measure the Hubble Constant,
the rate of expansion of the universe.

      "We have 3 years of work ahead of us and, until the project
is substantially complete, I won't speculate on what value of H0
this work will yield."

      Although this HST key project has the explicit goal of
getting H0, other astronomers have used Hubble to search for
Cepheids.  Previous HST observations carried out by a different
group also demonstrated HST's unique capability by resolving 27
Cepheids in another galaxy.

      The announcement was made at the 182nd meeting of the
American Astronomical Society in Berkeley, Calif.  The results
are detailed in several presentations by team members at that
meeting and are being submitted for publication in the
Astrophysical Journal.

      The team, led by Jeremy Mould (California Institute of
Technology, Pasadena, Calif.), consisted of Sandra Faber and
Garth Illingworth (Univ. of California, Santa Cruz);  Wendy
Freedman, John Graham and Robert Hill (Carnegie Institution of
Washington);  John Hoessel (Univ. of Wisconsin, Madison);  John
Huchra (Center for Astrophysics, Cambridge, Mass.);  Shaun Hughes
(Caltech) (Univ. of Calif., Santa Cruz);  Robert Kennicutt (Univ.
of Arizona, Tuscon);  Myung Gyoon Lee (Carnegie);  Barry Madore
(Caltech);  Peter Stetson (Dominion Astrophysical Observatory,
Victoria, British, Columbia);  Anne Turner (Univ. Arizona,
Tuscon); and Laura Ferrarese and Holland Ford (Space Telescope
Science Institute, Baltimore).

- end -
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

Article 3966 of sci.space.news:
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Path: nntpd2.cxo.dec.com!nntpd.lkg.dec.com!news.crl.dec.com!deccrl!decwrl!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: Hubble Finds Evidence of Stellar Close Encounters
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41    
Sender: [email protected]
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Organization: Jet Propulsion Laboratory
Date: Thu, 10 Jun 1993 18:53:00 GMT
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Paula Cleggett-Haleim
Headquarters, Washington, D.C.                       June 9, 1993
(Phone:  202/358-0883)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)


RELEASE:  93-109

HUBBLE FINDS EVIDENCE OF STELLAR CLOSE ENCOUNTERS

     NASA's Hubble Space Telescope (HST) has discovered a group
of stars that apparently have been canabalized of their cooler
outer gas layers by other passing stars, resulting in stellar
"naked cores" with surface temperatures five times hotter than
Earth's sun.

     "This is amazing.  These objects represent a totally new
population of very blue stars," says Guido De Marchi, of the
Space Telescope Science Institute (STScI), Baltimore, Md., and
the University of Florence, Italy.  "When we started wondering
what they could be, we realized that they may be among the first
observed stars to have been stripped."

     The stars are located deep in the core of M15, one of the
densest globular clusters known.  A globular cluster is a
"beehive swarm" of several hundred thousand stars held together
by each other's gravity.  If the cluster is exceptionally dense,
chances are increased for close encounters of stars, in which
bodies with strong gravitational attraction could strip other
stars of their outer material.

     "If our planet were there, we would see 100,000 stars closer
than Proxima Centauri, the closest star to Earth's sun," said De
Marchi.  "The night sky would look simply fantastic."

     De Marchi and Dr. Francesco Paresce of the European Space
Agency, explain that this could only have happened if stars are
so crowded together in the core they can be stripped of much of
their gaseous envelopes by the gravitational pull of bypassing
stars.

     This stellar cannibalism could only take place where stars
are so crowded together that chances for close encounters are
exceptionally high, they said.  De Marchi and Paresce interpret
the existence of this new class of stars as possible evidence
that the center of the globular cluster has contracted to an
extremely dense condition called "core collapse."

     This research by De Marchi and Paresce is being announced at
a press briefing today at the meeting of the American
Astronomical Society in Berkeley, Calif.

     The astronomers were surprised to discover about 15 hot blue
stars segregated at the very core of M15.  Their surface
temperatures are above 60,000 degrees Fahrenheit (the sun's
surface is 11,000 degrees Fahrenheit).

     This discovery was possible only with the Hubble Space
Telescope because it can resolve stars at the dense core of M15
that are only a blur from the ground.  The observations also
required Hubble's sensitivity to ultraviolet light to distinguish
the hot stars from the surrounding cooler stars.

     Such very hot blue stars can be made in several ways besides
stellar stripping, such as magnetically stirred-up super massive
stars, white dwarfs, or planetary nebulae.  However, the
researchers are quick to point out that none of these scenarios
explain why the stars are so concentrated and so numerous only at
M15's core.

     "This rules out a number of other hypotheses," says De
Marchi.  He explains that all the blue stars lie within a 1
light-year radius at the very core of the cluster.  What's more,
90 percent of them are concentrated at the very center of this
volume, within a 4/10th light-year radius.

Close Encounters Of The Stellar Kind

     According to this scenario, the new population of blue stars
was once the cores of red giant stars.  Such stars expand to
enormous sizes late in their lives, due to changes in the nuclear
"burning" at their cores.  If the sun were the size of a red
giant it would engulf the inner solar system out to the diameter
of Mars' orbit.

     Red giant stars are so distended that they have a weak
gravitational hold on their outer envelope of cool gas.  If a
normal main sequence star passes within a few stellar radii it
can rob gas from the red giant.  This stripping process can, in
theory, expose a star's core -- the nuclear fusion "engine" that
powers stars.

     However, conditions where stars are so crammed together are
unusual.  For example, in the Earth's stellar neighborhood the
stars are typically a million times farther apart than the
distance between the sun and Earth.

     Conversely, due to the relentless pull of gravity, the stars
at the core of M15 have converged so that they are at about 500
times the distance between the Earth and the sun.

     The astronomers used Hubble Space Telescope's Faint Object
Camera to probe the core of M15 (15th object in the Messier
Catalog) which is located 30,000 light-years away in the
constellation Pegasus.  M15 is visible to the naked eye as a hazy
spot 1/3rd the diameter of the full Moon.

Core Collapse

     Globular clusters are compact "beehive swarms" of several
hundred thousand stars loosely held together under the mutual
pull of gravity.  The stars are deflected by gravity if they pass
near each other.  During such close encounters a smaller, less
massive star steals momentum from the larger star.

     Because of these near-collisions, the massive stars lose
momentum and "fall" toward the center of the cluster, like
marbles rolling to the bottom of a funnel.  Given enough time,
massive stars should accumulate at the cluster's center.
Theoretically, this could become a runaway collapse where stars
quickly crowd together.

     Previous Hubble observations suggest that the cluster
probably contains powerful energy "storage batteries" in the form
of double star systems, which prevent the core from imploding all
the way down to a black hole.  The rapid orbits of two stars
about each other in tight binary systems create a powerful
reservoir of kinetic energy.  A few double stars can stir up the
motion of in-falling stars.  This would cause the core to
rebound, like squeezing and relaxing a rubber ball.

     Astronomers have long sought evidence for core collapse at
the heart of very dense clusters like M15.  To estimate the true
stellar density from ground-based visible light photographs,
however, has been difficult.  The Hubble observation does not
tell whether the core is still collapsing or rebounding.

     Previous research by a team led by Paresce found that
another class of unusual blue star, dubbed blue stragglers, also
dwell at the cores of some clusters.  However, even the
"stragglers" are not as hot nor as blue as the new population of
blue stars in M15.  Most of the blue stragglers are probably
double stars that gravitationally capture each other.  The
capture stirs-up the stragglers' nuclear fuel.  The star "resets
its clock" to relive a bright and hot youth.

     The researchers plan to use Hubble to peer into the cores of
other globular star clusters to see if this new class of star
dwells elsewhere as well.

- end -

NOTE TO EDITORS:    A photo to illustrate this release is
available through NASA's Broadcast and Imaging Branch by calling
202/358-1900.  The photo number is:

        Color:  93-HC-240             B&W:  93-H-263

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

Article 3983 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!pa.dec.com!decwrl!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: HST Update - 06/14/93 (Safe mode)
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41    
Keywords: HST
Sender: [email protected]
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Mon, 14 Jun 1993 16:07:00 GMT
Approved: [email protected]
Lines: 17

                              HUBBLE SPACE TELESCOPE
                                    SAFE MODE
                                 June 14, 1993

     On June 14, 1993 at 0320Z, Goddard Space Flight Center requested support
from the DSN (Deep Space Network) because the Hubble Space Telescope (HST) went
into safe mode.  DSS-16 (Goldstone 26 meter antenna) was called into service.
The project reported that HST went into safe mode at 0017Z on June 14.
A DSS-66 (Madrid 26 meter antenna) support has been requested by Goddard
for use later today.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The tuatara, a lizard-like
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | reptile from New Zealand,
|_____|/  |_|/       |_____|/                     | has three eyes.

From:	US1RMC::"[email protected]" "Ron Baalke" 16-JUL-1993 
To:	[email protected]
CC:	
Subj:	Hubble Supports Black Hole Model for Active Galaxies

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                           July 16, 1993
(Phone:  202/358-0883)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)

RELEASE:  93-130

HUBBLE SUPPORTS BLACK HOLE MODEL FOR ACTIVE GALAXIES

	A team of astronomers reports that recent NASA Hubble
Space Telescope (HST) observations of a class of active
galaxies further support the theory that they are fueled by a
massive black hole at the center.

	The researchers say the HST results rule out vigorous
star formation as the alternative explanation for the
mysterious power source behind quasars and extremely bright
galactic nuclei.

	"Our observations provide perhaps the most direct
evidence to date that normal Seyfert galaxies and quasars are
not powered by a burst of star formation," says Alexei V.
Filippenko, Professor of Astronomy, University of California at
Berkeley.  "The most likely alternative, then, is the standard
model in which the energy is provided by matter falling into a
black hole."

	Seyfert galaxies are nearby galaxies with extremely
bright central regions that often obscure the much dimmer stars
in the surrounding galaxy.  Quasars -- quasi stellar radio
sources -- are among the most distant objects in the universe
and are visible from Earth only because they are so bright.

	Both types of objects, collectively referred to as active
galactic nuclei (AGN), give off prodigious amounts of energy.
Much of the radiation is in the form of high-energy x-rays and
gamma rays.

Convincing Observations

	Observations over the past 30 years have convinced most
astronomers that the only object capable of producing such
tremendous amounts of energy in a relatively small galactic
core is a black hole.

	A black hole is a theoretical object that is so compact
its intense gravity prevents even light from escaping.  In the
standard model for AGNs, dust, gas and stars falling into the
black hole heat up as they collide with one another, releasing
tremendous amounts of radiation.

	A competing explanation is the starburst hypothesis,
which proposes some active galaxies -- in particular so-called
Seyfert galaxies and some dimmer quasars -- are bright because
of vigorous star formation at the center.  This starburst
activity generates massive hot stars that evolve rapidly and
explode after a mere 10 million years.

	This model, championed by Roberto Terlevich of the Royal
Greenwich Observatory in Cambridge, England, predicts that
light from the nucleus of an active galaxy should show
characteristics of light from very hot stars.  In particular,
it should show ultraviolet absorption lines -- specific
wavelengths in the ultraviolet part of the spectrum that are
blocked or absorbed by cooler gas in the atmospheres of the stars.

	"Terlevich's hypothesis was generally dismissed by
astronomers, but we felt it was conceivable that some of the
least luminous active galaxies could have enough stars in their
nuclei to produce this amount of energy," Filippenko says.
"Among astronomers, there is a tendency to associate anything
mysterious with a black hole, but we thought it was important
to test the hypothesis and not jump on the black-hole bandwagon."

	The astronomers chose to use NGC 4395 to test the
starburst hypothesis because the region around the nucleus is
nearly devoid of stars, which could contaminate the spectra and
make the findings ambiguous.

	Filippenko and his colleagues used the Faint Object
Spectrograph aboard the HST to make a 7-hour observation of the
nucleus of NGC 4395.  They did not detect any absorption lines
that could be ascribed to stars in the nucleus.

	"We can say with confidence that there is no unambiguous
evidence that stellar processes are responsible for light
emitted by the nucleus of this galaxy," Filippenko says.

	In addition, an image of the galaxy obtained with HST's
Planetary Camera shows a galactic center at most 2 light years
across -- less than half the distance from the sun to the
nearest star.

Starburst Hypothesis

	"This is smaller than all but the smallest star clusters,
which are extremely rare, " Filippenko says.  "Although the
size alone does not rule out the possibility of a star cluster
being responsible for the light, it makes this unlikely."  He
concludes, "The starburst hypothesis doesn't work for this nearby 
active galaxy, so it probably doesn't work for most others."

	The findings are reported in the June 20, 1993, issue of
The Astrophysical Journal by Filippenko, graduate student Luis
C. Ho and California Institute of Technology astronomer Wallace
L.W. Sargent.

	Filippenko and Sargent identified NGC 4395 4 years ago as
the least luminous and nearest Seyfert galaxy known, based on
its spectrum.  It is about 8 million light years away in the
direction of the constellation Canes Venatici (The Hunting Dogs).

	Seyfert galaxies, quasars and other AGNs are generally
thought to comprise only about one of every 100 known galaxies.
Based on a survey of more than 500 galaxies over the past 10
years, Filippenko and Sargent think the number may be closer to
one in 10.

	Previous Hubble observations have found additional
circumstantial evidence for the presence of massive black holes
in the core of active galaxies:  dust disks, "light-cones" of
ionizing radiation, and extremely dense stellar concentrations
consistent with theoretical models for the presence of a black hole.

	Support for the research was provided by NASA through the
Space Telescope Science Institute and the National Science Foundation.
The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Common sense is not very
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | common.
|_____|/  |_|/       |_____|/                     | 

Paula Cleggett-Haleim)
Headquarters, Washington, D.C.                      July 19, 1993

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore

RELEASE:  93-133


        A team of astronomers using NASA's Hubble Space Telescope (HST) has
discovered a "double nucleus" in the center of the neighboring spiral galaxy
M31, located in the constellation Andromeda.

        A nucleus is a dense clustering of stars at the very center of a
galaxy.

        "Hubble shows that the M31 nucleus is much more complex than previously
thought," said Dr. Tod R. Lauer of the National Optical Astronomy
Observatories, Tuscon, Ariz.

        The astronomers report that the brighter member of the double nucleus
might be the remnants of another galaxy cannibalized by M31. They say that an
alternative possibility is that dust might dim the core to create the illusion
of a pair of separate star clusters.

        The Hubble images intensify the mystery of what's happening in the
center of this galaxy," said Lauer. "Neither interpretation offers a complete
explanation of the M31 nuclear structure."

        The double nucleus discovery is based on image analysis conducted by
Lauer, Dr. Sandra M. Faber of the University of California, Santa Cruz, and
other members of the HST Wide Field/Planetary Camera Imaging Team.


        The HST pictures show two bright spots at the heart of the M31 galaxy.
The dimmer of the two "light-peaks" appears to mark the exact center of the
galaxy.  The brighter peak is at least 5 light years away from the true center,
but corresponds to what astronomers previously had thought was the nucleus of
M31, based on ground-based observations.

        Well-known as the Andromeda Galaxy, M31 (the 31st object in a catalog
of non-stellar objects compiled by French astronomer Charles Messier in 1774)
is located only 2.3 million light years away, making it the nearest major
galaxy to the Earth's own Milky Way. M31 dominates the small group of galaxies
of which the Milky Way is a member and can be seen with the naked eye as a
spindle-shaped "cloud" the width of the full Moon.

        Like the Milky Way, M31 is a giant spiral-shaped disk of stars, with a
bulbous central hub of older stars.  M31 has long been known to have a bright
and extremely dense grouping of a few million stars clustered at the very
center of its spherical hub.  As seen from large ground-based telescopes, the
starlight blends to resemble a single bright, almost point-like source.
Previous ground-based observations gave little hint of the true structure of
the core, which is now revealed by Hubble.

Pinpointing the M31 nucleus

        In the 1960's the first high resolution photographs of M31's core were
obtained by Stratoscope II, a balloon-borne observatory.  The images were not
as sensitive as Hubble's and only showed a single bright cluster of stars.

        An important clue came with observations obtained in 1986 by the late
Jean-Luc Nieto, then at the Pic du Midi Observatory in France. He found that
the bright nucleus was offset by several light-years from the exact center of
the galaxy's central bulge.  The new HST images show that the dimmer peak
instead is the true nucleus and that the bright point of light evident from
ground-based telescopes corresponds to the brighter of the two peaks.

A cannibalized galaxy?

        One possible explanation for the second cluster being offset from the
exact center is that it is the remnant of a smaller galaxy that fell into M31
perhaps a billion or so years ago.  The smaller galaxy's core is the only
surviving fossil relic of the galactic collision.

        A problem with the collision scenario is that the remnant core should
be torn apart by the massive black hole hypothesized to dwell at the exact
center of M31. The suspected black hole would be located in the middle of the
dimmer peak uncovered by HST.


        In 1988, the first evidence for a black hole at the exact center of M31
came from ground-based observations by Dr. John Kormendy (now at the University
of Hawaii), and independently, by Dr. Alan Dressler (Observatories of the
Carnegie Institution of Washington), and Dr. Douglas O. Richstone (University
of Michigan). Their data indicated an abrupt increase in the orbital velocities
of stars in the center of the M31 nucleus.

        This led the astronomers to conclude that M31 must have a strong but
unseen concentration of mass at its center.  A black hole at least 10 million
times the mass of the sun is the most likely type of object matching these
characteristics.  A black hole is a theoretical object that is so dense that
even light cannot escape its intense gravitational pull.

        If such a black hole really exists, than the remnant core from the
cannibalized galaxy would be torn apart in just a few 100,000 years. "This is
very short in cosmic time," said Lauer. "We would have to be looking at the
galaxy at a very special time to see it now."

        One way for the remnant to survive for a much longer time is if it has
its own massive black hole.  Gravity from a black hole in the remnant would
hold it together against destruction from the other black hole at the M31
center.

        "In retrospect, there may be evidence for this possibility in the
spectra obtained by Kormendy, Dressler and Richstone, said Lauer. "One problem
with this picture, however, is if the black hole in the remnant were too big,
it would distort even the true nucleus of M31."

A dust lane bisecting the nucleus?

        Another interpretation of the "twin peaks" is that the bright spot is
just the outer portion of a large nuclear star cluster and that the central
portions have been obscured by dust.  A thick ring of dust might even cut
across the nucleus, creating the illusion of two separate objects rather than
one elongated structure.

        Lauer explains that the problem with this idea is that normal galactic
dust would scatter the light such that it would appear reddened. "But this is
not the case, there are no color effects at all," he emphasized. "This means
that the dust grains would have to be much larger than average." In the Milky
Way galaxy, however, the interstellar dust grains are roughly the same size.

        "We can only guess that earlier nuclear activity in M31 would have
destroyed all the fine dust grains that would cause color effects," said Lauer.


        M31 is an ideal target for Hubble once the telescopes's optics are
improved during a Space Shuttle servicing mission in December. Spectrographs
aboard Hubble will dissect the light from the two peaks of the double nucleus
and determine if they are truly separate clusters.  Astronomers will be able to
measure the velocity of stars to pin down whether there is a black hole in
either or both.

        This is the latest in a series of Hubble observations that have
uncovered unusual structures in the cores of galaxies.  Some of them might be
fossil evidence of galactic collisions.  Hubble also has resolved very dense
concentrations of stars in the cores of other galaxies that are circumstantial
evidence that massive black holes are common among galaxies.

From the "JPL Universe"
July 16, 1993

Putting WF/PC-2 in place may require the hands of a surgeon
By Diane Ainsworth

     What will it take to slide a 280-kilogram (620-pound),
wedge-shaped camera into the side of NASA's orbiting Hubble Space
Telescope without so much as bumping an edge of the instrument?
     NASA thinks it may take the hands of a surgeon.
     So Story Musgrave, a surgeon by training and payload
commander on STS-61 -- the first Hubble telescope servicing
mission -- has been practicing, along with four other crew
members, in a 12-meter-deep (40-foot-deep) water tank at Marshall
Space Flight Center in Huntsville, Ala. The tank simulates the
weightlessness of space.
     "Working in the water tank, and in the Weightless
Environment Training Facility at Johnson Space Center, we are
learning things like reach and visibility," Musgrave told members
of the press at a recent Hubble Space Telescope News Writers
Workshop in Baltimore.  "We are learning the right kinds of
positions we will use in the work sites on orbit, how to work in
spacesuits and how to restrain objects in zero G."
     Musgrave and his colleagues were halfway through a
three-week water training session at Marshall Space Flight Center
when he took time out to give the press an astronaut's
perspective on the upcoming December 1993 Hubble Space Telescope
servicing mission via remote satellite link from Huntsville.
     The 57-year-old veteran of four space flights, who had
recently suffered frostbite on several fingertips during a
training session, didn't flinch when the inevitable question --
would the crew be able to fix everything -- came up.
     "It's a bunch of hard work, but I think we're going to get
the whole thing done," he declared enthusiastically. "People
should remember that during the lunar program, we were working on
the moon eight hours a day, three days in a row," he said.
"During this mission, we will be working (out in space) six hours
every other day."
     The Space Shuttle Endeavour is scheduled to rendezvous with
and capture the Hubble Space Telescope during STS-61, tentatively
set for launch at 4:30 a.m. Eastern Standard Time on Dec. 2.
Astronauts will retrieve the 13.1-meter-long (43-foot-long)
orbiting telescope on the third day of the mission.
     Once the telescope has been captured by the shuttle's
15-meter (50-foot) mechanical arm, it will be secured upright in
the cargo bay for servicing. One-hundred-and-seventy-one tools,
ranging from simple tote bags to sophisticated, battery-operated
power tools, have been prepared to assist the astronauts in the
repair mission.
     Working in pairs on alternating days, four of the seven crew
members -- Musgrave and mission specialists Jeffery Hoffman,
Thomas Akers and Kathryn Thornton -- will be spacewalking a
record five days of the mission and, perhaps, as many as seven
days. Each spacewalk will last from five to eight hours,
depending on how long the oxygen supplies last.
     Three priorities on STS-61 have been identified as crucial
to the success of the mission: replacing the telescope's two
12-meter (39-foot) solar panels; replacing the
Wide-Field/Planetary Camera; and installing the Corrective Optics
Space Telescope Axial Replacement, known as COSTAR.
     Musgrave said the crew has been working with a full-scale
training version of the camera to learn how to delicately remove
the cover of the pickoff mirror, which points out from the tip of
the camera, before the instrument is guided like a giant drawer
into the side of the telescope.
     "You are about this far away from the mirror," he said,
extending his arm about 30 centimeters (12 inches) in front of
his face, "and you've got the optics of an incredibly important
instrument, probably one of the most important instruments ever
flown. It has to be protected, it cannot be touched at all, and
you have to give it the most tender loving care of all until it
is inserted into the telescope."
     The astronauts have learned from water training that the
Wide-Field/Planetary Camera will have to be handed off to one
astronaut, who will be holding onto the side of the telescope
from his or her partner, who will be standing on the shuttle's
robot arm.
     "We discovered that the person on the arm will not have the
visibility to slide the camera into the side of the telescope,"
Musgrave said.  "Keep in mind that we are wearing big helmets and
visors that limit our sight, how much we can turn our heads and
where we can put our eyeballs."
     Two extra days have been built into the 11-day mission to
give the astronauts a day off and to allow for contingencies --
anything that might go awry or require research from the ground.
     "If we find that we're running behind in some task or
running ahead of schedule, we will be able to move on to other
tasks," Musgrave said. "We are being trained to accommodate
surprises, changes in the flight plan, things that may interrupt
or delay our activities."
     The crew will begin its daily spacewalks on the day
following telescope capture, Dec. 5, said Milt Heflin, flight
director for the first servicing mission.
     The first extravehicular activity (EVA) will involve
replacing three backup gyros that are used to point and track the
telescope and preparing the solar arrays for deployment, Heflin
said.
     The second EVA will be devoted to replacing the solar
arrays, followed on the next EVA day by replacement of the
Wide-Field/Planetary Camera. The fourth EVA will be used to
remove the 220-kilogram (487-pound), telephone booth-sized High
Speed Photometer and replace it with the 272-kilogram (600-pound)
COSTAR. All of the science instruments will be returned to Earth
to determine how well they weathered the space environment.
     NASA is considering a follow-up mission nine to 12 months
after STS-61 if all of the repairs are not completed. Although
Musgrave said he'd "jump at it" to be one of the returning
astronauts, he also voiced his confidence that the STS-61 crew
would be able to accomplish its mission regardless of the
surprises or setbacks.
     "In my 26 years with NASA, I have never seen such a
detailed, energetic approach to trying to identify all of the
surprises, to look ahead to all of the possibilities, all of the
contingencies that might happen during the mission," he said.
     "But this is not your local garage ... this is spaceflight,
this is one of the most ambitious things we have ever attempted.
It's a drama, and it's going to have to be played out."
                                  ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | When given a choice between
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | two exciting things, choose
|_____|/  |_|/       |_____|/                     | the one you haven't tried.

Sarah Keegan
Headquarters, Washington, D.C.                        August 27, 1993

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

Ray Villard
Space Telescope Science Institute, Baltimore, Md.


RELEASE:  93-156

        Astronomers using the NASA Hubble Space Telescope have taken an image
for the first time of a double star that is emitting enormous amounts of x-ray
energy and previously only could be "seen" by instruments that detect x-rays.

        "I was just doing a routine study of the dynamics and population of
stars in the cluster which harbors this binary (double star) system," said Dr.
Ivan King of the University of California at Berkeley. "My decision to take an
ultraviolet image was a shot in the dark."

        He noted that the double star never could have been seen with ground-
based telescopes.  However, Hubble's high resolution and ultraviolet
sensitivity clearly distinguish the star from the others around it.  King's
picture was obtained by the European Space Agency's Faint Object Camera aboard
Hubble.

        The binary system is in the heart of a dense globular cluster of stars
called NGC 6624.  It is about 30,000 light years from Earth in the
constellation Sagittarius.

        One binary system member is a neutron star, the corpse of a massive
star that exploded eons ago.  It is extremely dense and compact, and exerts a
powerful gravitational pull.  Its companion, which has less mass, is a white
dwarf, the remnant of a burned-out star which once was like Earth's sun.

        The two stars are only about 100,000 miles apart and complete one orbit
of each other every 11 minutes, making it the fastest binary system known.

        During this deadly dance, the neutron star's intense gravity strips
helium from its companion, accumulating a disk of the gas around the neutron
star.  This continuous infall of gas produces a steady stream of x-ray energy.
The energy, or radiation, heats the gas disk to temperatures greater than
100,000 degree Fahrenheit.

        When enough super-hot helium accumulates in the disk, it spontaneously
ignites with the force of an enormous nuclear fusion bomb.  The outburst of
energy is of far greater intensity than the steady infall emission and is
called an "x-ray burster." Astronomers have identified about 30 x-ray bursters
in the universe, most near the center of the Milky Way galaxy.

        Astronomers are interested in binary systems like this to gain greater
insight into the physics of matter falling onto gravitationally powerful,
compact objects such neutron stars and black holes.  This mechanism is thought
to be the primary source of energy in a variety of exotic objects in the
universe, ranging from x-ray sources in the Milky Way to quasars, the most
energetic objects known.

        Kings plans to use Hubble's High Speed Photometer to look for
brightness changes as the binary goes around its 11-minute orbit.  He also will
look optically for the mysterious flickering at 30-40 times per second that has
been seen in x-rays.

        "There is only a remote hope of seeing something in the millisecond
range, but we can't afford not to look," he says.  HST eventually will be used
to make spectroscopic observations that should confirm the nature of the star.

        The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency.

- end -

[Note: A GIF of the image is promised in a few days... -dg]

    re .307
    
>        The two stars are only about 100,000 miles apart and complete one orbit
>of each other every 11 minutes, making it the fastest binary system known.
    
    Over 700 km/s orbital speed - mind-boggling.

Article: 43142
Newsgroups: sci.astro
From: [email protected] (BEN)
Subject: Asteroid 19 Fortuna resolved
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Tue, 14 Sep 1993 23:14:22 GMT
 
People,
 
Not to publish via the Internet, but I would like to share a image of
asteroid 19 Fortuna taken last Friday with the Planetary Camera of the
Hubble Space Telescope. 
 
The image was taken for my HST snapshot program to look for satellites
of asteroids.  There isn't any earth-shaking science to be done here - 
I don't see any satellites - but the neat part is that Fortuna happened
to be passing within a few arcseconds of a field star of about the same
peak-pixel brightness.  I have set the contrast to emphasize the inner
core of the point-spread function for both objects, demonstrating very
nicely the difference between a point source (the star) and a resolved
object only 0.20 arcseconds in diameter. 
 
An extraction from the frame is posted as fortuna.gif at stsci.edu in
directory stsci/epa/gif as fortuna.gif, along with a text file
fortuna.txt giving some details of the observation.  Be sure to use
binary file transfer for the GIF file.  If you cannot ftp to stsci.edu,
drop me a note and I can send you a BINHEX4 version. 
 
Co-Investigators on this HST program include Charlie Kowal and Ed Wells
of Computer Sciences Corporation, Alex Storrs of STScI, and David
Tholen of the University of Hawaii.
 
Enjoy, and share the image any way you like, just please don't publish it!  
 
Ben Zellner
Computer Sciences Corporation
Space Telescope Science Institute
 
Article: 43192
Newsgroups: sci.astro
From: [email protected] (BEN)
Subject: error re asteroid 19 Fortuna
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Wed, 15 Sep 1993 19:01:41 GMT
 
As several people have pointed out, the text file that accompanied my 
posting in stsci.edu from last Friday's image of 19 Fortuna contained 
a typo. The distance of the object was around 231,400,000 km, not 231,000 
as posted.  
 
The error should have been corrected by the time you see this.
 
Ben
 

Article: 43285
Newsgroups: sci.astro
From: [email protected] (STSCI PUBLIC INFO. MGR.(410-338-4514))
Subject:  FAQ- science from Hubble Space Telescope
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Thu, 16 Sep 1993 22:43:09 GMT
 
Hubble Space Telescope's Scientific Highlights 
 
Prepared by the
Educational and Public Affairs Office
Space Telescope Science Institute
 
PLANETS
 
*    Conducting long-term observations of global weather changes on Mars.
 
*     Followed the development of a rare storm on Saturn.
 
*    Resolved Pluto and Charon as completely separate objects. 
 
*    Monitoring long term weather changes on Jupiter and auroral activity.
 
*    Measured the size of the atmosphere of the Jovian moon Io,
     and looked for surface changes.
 
 
STELLAR EVOLUTION
 
*    Uncovered the strongest evidence yet that many stars form
     planetary systems by discovering disks of dust around 15
     newly formed stars in the Orion Nebula, a starbirth region
     1,500 light-years away.  The HST images confirm more than
     two centuries of speculation, conjecture and theory about
     the genesis of a solar system. Such disks are considered a
     prerequisite for the formation of solar systems like our own.
 
*    Discovered a luminescent ring around Supernova 1987A,
     resolve the supernova's cloud of expanding debris for the
     first time, and use the ring's angular diameter to determine
     an accurate distance to a neighboring galaxy.  
 
*    Revealed  the structure behind the shock waves in the Cygnus
     Loop supernova remnant. The HST image  allows  astronomers 
     to compare directly the actual structure of the shock with
     theoretical model calculations. Hubble's detailed image
     shows the blast wave overrunning dense clumps of gas which
     are small enough to fit inside our Solar System.
 
*    Provided the first clear view of one of the hottest known
     star (360,000 degrees Fahrenheit), which lies at the center
     of the "Butterfly Nebula" NGC 2440.
 
*    Observed the eruption of a stellar flare on the star AU
     Microscopium, providing the first direct evidence for
     "proton-beaming" at the onset of a stellar flare. 
 
*    Provided the earliest look ever at a rapidly ballooning
     bubble of gas blasted off a star.  The shell surrounds Nova
     Cygni 1992, which erupted on February 19, 1992. HST reveals
     a remarkably circular yet slightly lumpy ring-like
     structure. A striking relic of the explosion is an unusual
     bar-like structure across the middle of the ring. It might
     mark the edge-on plane of the orbits of the two members of
     the binary system. 
 
 
STAR CLUSTERS 
 
*    Discovered young globular star clusters at the core of a peculiar 
     galaxy -- the equivalent of finding "Jurassic Park" in space.
 
*    Resolved stars in the cores of a globular star clusters and
     uncovered evidence that some cores may be rebounding or
     collapsing due to stellar dynamics in such a crowded environment.
 
*    Found blue straggler stars in core of a globular cluster,
     providing evidence of stellar capture and merger.
     
*    Discovered a cataclysmic variable star in the core of
     cluster 47 Tucane, the first optical counterpart to an x-ray
     source in a globular cluster.
 
*    Discovered a new class of  extremely hot and blue stars in
     the core of cluster M15. They are possibly the "naked cores"
     of stars that were stripped of their outer shells of gas
     through close encounters with other stars. This new
     population might be fossil evidence that the cluster's core
     had contracted to a extremely dense condition called "core collapse". 
 
*    Detected the optical light from an unusual double star that
     is a source of violent bursts of X-rays. The position of the
     binary coincides with the position of the X-ray burster 4U
     1820-30, which is located in the core of the globular cluster NGC 6624. 
 

GALAXIES
 
*    Yielded direct observational evidence for galaxy evolution
     by resolving the different shapes of galaxies that existed
     long ago. HST revealed that many ancient spiral galaxies
     have since disappeared, possibly through mergers, collisions, 
     and fading.  The Hubble images provide the first unambiguous 
     evidence for the influence of environment on a galaxy's form.
 
*    Provided the first direct view of an immense ring of dust
     that fuels a suspected massive black hole at the heart of
     the giant elliptical galaxy NGC4261 and the spiral galaxy
     M51. Even more surprising is the discovery of a secondary
     ring or dust lane orbiting the M51 black hole.
 
*    Uncovered circumstantial evidence for the presence of a
     massive black hole in the core of the neighboring galaxy
     M32, and the giant elliptical galaxy M87. Both M32 and M87
     have a distinctive central concentration of starlight called
     a "cusp" that is probably shaped by the concentrated
     gravitational field of the black hole. This implies that
     massive black holes may be quite common among "normal" galaxies.
 
*    Resolved detailed structure and unique differences in the
     shapes of optical extragalactic jets which are believed to
     be powered by massive central black holes. 
 
*    Imaged extremely distant and unusual galaxies during a
     "serendipitous" survey of the heavens. HST revealed a wide
     variety of shape and structure in these distant galaxies,
     which previously appeared as fuzzy blobs in ground-based sky surveys. 
 
*    Uncovered new details in the most distant known galaxy
     (4C41.17- 14.5 billion light-years away) which formed less
     than a billion years after the Big Bang. HST resolved bright
     luminous knots that may be gigantic clusters that line up
     along a high-speed jet of gas being ejected from the
     galaxy's center. A massive black hole at the core is the
     likely powerhouse behind the jet. 
 
 *   Discovered a double nucleus in the core of an active galaxy,
     Markarian 315. The brighter member of the pair is the
     energetic core of the galaxy that probably contains a black
     hole.  The fainter companion is  the core of a galaxy that
     has merged with Markarian 315. The image helps confirm that
     galaxy mergers may be one mechanism for driving gas deep
     into the heart of a galaxy, according to astronomers.  This
     raw material fuels a massive black hole, theorized to be the
     "central engine" in active galactic nuclei.
 
*    Found a double nucleus in the center of the neighboring
     spiral galaxy M31. The brighter member of the double nucleus
     might be the remnants of another galaxy cannibalized by M31.
     An alternative possibility is that dust might dim the core
     to create the illusion of a pair of separate star clusters. 
     
*    Uncovered further support for the theory that active
     galaxies are fueled by a massive black hole at the center.
     HST's image of the Seyfert galaxy, NGC 4395, shows a
     galactic center at most two light years across. The results
     rule out vigorous star formation as the alternative power
     source, because HST did not detect any absorption lines that
     could be ascribed to stars in the nucleus. 
 
 
COSMOLOGY
 
*    Allowed astronomers to take a major first step in
     redetermining the  expansion rate of the universe by
     detecting 27 Cepheid variable stars in a faint spiral galaxy
     called IC 4182. Cepheid variables are "standard candles" for
     estimating distances to galaxies,  The expansion rate, known
     as the Hubble Constant, is one of two critical numbers
     needed for making a precise determination of the size and
     age of the universe.
 
*    Discovered the presence of Boron, fifth lightest element, in
     a very ancient star. If the boron was produced in the first
     few minutes of the birth of our universe, it implies that
     there were inhomogeneities in the cosmological Big Bang.
 
*    Detected more than a dozen intergalactic hydrogen clouds
     within less than a billion light-years of our Milky Way
     galaxy. Follow-on observations with HST  suggest that,
     instead of being randomly distributed, the nearby primordial
     clouds may actually be associated with galaxies or clusters
     of galaxies.
 
*    Provided unprecedented information about the frequency of
     gravitational lensing by galaxies based upon a survey of 300
     quasars. These results set new constraints that cosmological
     models must satisfy, and already rule out some of the
     extreme theories for the origin of the universe.

    	The image of 19 Fortuna may be found at:
    
    	PRAGMA::PUBLIC:[NASA.MARSH]FORTUNA.*

pragma::public:[nasa]hst_fortuna.*

- dave

Newsgroups: sci.astro,sci.space
From: [email protected]
Subject: HST does work - a GO's perspective
Organization: Space Telescope Science Institute
Date: Fri, 24 Sep 1993 13:10:13 GMT



Well this week I got to see HST work from the other perspective - Guest
Observer.  The project I worked on obtained about 13 hours of HRS spectra of a
very interesting binary system at several phases.  At this point I can only say
that the data are spectacular.   In all my years of observing I have seen a lot
of nice data but these really stand out.  I would also like to add that no
where, not on or above earth, except with HST, could these data have been
obtained.  Furthermore, the team here did a great job to help me coordinate
these observations with IUE and VLA. This is note is not meant to start yet
another debate about HST but rather to re-emphasize that HST is working and
working well.  Well, off to the workstation to analyze my data....

----------------------------------------------------------------------------
Robert Dempsey                                        (410) 338-1334
STScI/PODPS                                                               

One of the symptoms of an aproaching nervous breakdown is the belief that
one's work is terribly important.  - Bertrand Russell
----------------------------------------------------------------------------

Sarah Keegan
Headquarters, Washington, D.C.                 September 24, 1993

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.

George Diller
Kennedy Space Center, Fla.

RELEASE:  93-169


     NASA officials have decided that further testing on the Wide
Field/Planetary Camera II (WF/PCII), an instrument scheduled to
fly on the Hubble Space Telescope Servicing Mission in December,
might be necessary.

      The instrument, now at the Kennedy Space Center (KSC),
Fla., may be returned to the Goddard Space Flight Center,
Greenbelt, Md., for the tests, according to Joseph Rothenberg,
Associate Director of Flight Projects for Hubble Space Telescope
(HST) at Goddard.  The additional testing is not expected to
impact on the planned Dec. 2 launch.

     A decision on whether the instrument will be returned to
Goddard is expected to be made Sunday, Rothenberg said.
Officials are waiting until Sunday to allow completion of further
testing, which is being conducted at the Maryland facility.
Optical experts at Goddard conducted tests until 1:30 a.m. Friday
and will continue practically around-the-clock until early Sunday
morning, Rothenberg said.

     Further testing of the instrument is required because of new
results from earlier tests at Goddard which show that the focus
point for HST might be outside the adjustment range for on-orbit
focusing by remote control from Goddard, Rothenberg explained.
Rothenberg said the instrument may be returned to Goddard for 3
weeks.

     Closeout of the solar arrays and the Corrective Optics Space
Telescope Axial Replacement (COSTAR) instrument at KSC are
continuing at the Payload Hazardous Servicing Facility.  On Oct.
1, they will arrive at the Vertical Processing Facility to begin
compatibility tests with the Space Shuttle, KSC officials said.
If the decision is made to return WF/PC II to Goddard, the
instrument would rejoin the flow without schedule impact after
its return to KSC, according to KSC officials.

    On orbit focusing, according to Rothenberg, involves focusing
the WF/PC II by moving the observatory's secondary mirror.  Once
the WF/PC II is focused, the COSTAR, which has adjustable
mirrors, is focused so both instruments are in focus using the
same secondary mirror position.

     In a more detailed analysis of the test previously carried
out at Goddard, officials discovered error margins that showed
that the WF/PC II might be at the very edge of COSTAR's
adjustment range and that focusing both instruments
simultaneously might not be possible.  The magnitude of the error
is about 7.5 millimeters, or about one third of an inch,
Rothenberg said.

     This data, he explained, is inconsistent with results of all
other testing carried out at Goddard and at the Jet Propulsion
Laboratory, Pasadena, Calif., where the instrument was built.  As
a result, he continued, a procedural error in the testing or a
discrepancy in the way the test was set up is believed to have
caused an erroneous measurement.

    Rothenberg said NASA will not launch the WF/PC II until the
discrepancy is understood.  The planned 11-day mission will have
from five to seven spacewalks for servicing the observatory.  The
WF/PC II is a second generation instrument that will replace
WF/PC I.

    HST was launched in April 1990.  Approximately 2 months after
launch, a manufacturing flaw in the observatory's primary mirror
was discovered that resulted in limiting the scientific
achievements of the spacecraft.  The COSTAR, built by Ball
Aerospace, Boulder, Colo., is designed to correct for the
manufacturing flaw and improve the capabilities of the three
remaining instruments on the observatory.

Article: 43771
Newsgroups: sci.astro
From: [email protected] (Zoltan Levay)
Subject: HST PR Images via ftp
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Fri, 24 Sep 1993 18:00:47 GMT
 
HOW TO RECEIVE HUBBLE SPACE TELESCOPE IMAGES ELECTRONICALLY
 
The Space Telescope Science Institute's Educational and Public Affairs
Office offers an electronic news service which makes Hubble Space
Telescope public release images available electronically as part of
the STScI Electronic Information Service (STEIS).
 
Downloading the images requires that you have access to an Internet
host computer that supports Anonymous File Transfer Protocol (FTP).
 
Call the STEIS bulletin board by typing:  "ftp stsci.edu".  The
following example illustrates a typical session.  Note that various ftp
programs may differ in the specific interaction, but the commands will
be similar.
 
prompt "STSCI.EDU>"
-  enter "login"
prompt " FOREIGN USERNAME: "
-  enter "anonymous"
prompt "PASSWORD: "
-  enter "[your last name]"
-  enter "cd stsci/epa/tiff"   (or gif)
-  enter "dir"                 (List image file names)
-  enter "binary"              (Set transfer mode)
-  enter "get [image file]"    (Retrieve a file)
 
Under the directory "epa", there are two subdirectories containing HST
images in different formats.  The "gif" directory contains images in
GIF format which supports up to 256 colors (8-bits per pixel).  The
"tiff" directory contains images in TIFF format, which supports full
color (24-bits per pixel).  All image data are binary, so when
transferring using ftp, make sure to set the transfer mode to "binary".
Both image directories include plain (ASCII) text files containing
descriptions of the images.  In addition, there are README files which
describe the contents generally, and Index files which give a bit more
information on each image.
 
*************************************************************
 
/stsci/epa/gif  as of September 1993
 
File Name        Size        Instrument   Object
---------        ----        ----------   ------
fortuna.gif      614x346     PC           Asteroid 19 Fortuna
m31c.gif         1132x769                 M31 galaxy composite
mars.gif	 512x512     WF/PC        Mars, composite color
marsb.gif        512x512     WF/PC        Mars, blue frame
marsg.gif        512x512     WF/PC        Mars, green frame
marsr.gif        512x512     WF/PC        Mars, red frame
ngc1741.gif      849x615     FOC          NGC 1741 starburst in galaxies
ngc2440.gif      700x700     WF/PC        NGC 2440
ngc4261.gif      459x427     WF/PC        NGC 4261 galaxy
ngc6624.gif      466x243     FOC          NGC 6624 globular cluster
ngc7252.gif      512x512     WF/PC        NGC 7252 (Atoms for Peace Galaxy)
orib.gif         680x524     WF/PC        Orion Nebula, blue frame
orig.gif         680x524     WF/PC        Orion Nebula, green frame
orir.gif         680x524     WF/PC        Orion Nebula, red frame
 
 
/stsci/epa/tiff  as of September 1993
 
File Name        Size        Instrument   Object
---------        ----        ----------   ------
cloop.tiff       1519x1526   WF/PC        Cygnus Loop nebula
jupiter.tiff     800x800     WF/PC        Jupiter
m31.tiff         340x290     WF/PC        M31 Nucleus
m31c.tiff        1132x769                 M31 galaxy composite
m51.tiff         512x512                  M51 galaxy
mars.tiff        512x512     WF/PC        Mars
mb3.tiff         175x133
ngc2300.tiff     285x340     ROSAT        NGC 2300 galaxies
ngc4261.tiff     795x631     WF/PC        NGC 4261 galaxy
ngc5728.tiff     669x515     WF/PC (PC)   NGC 5728 Seyfert galaxy
ngc6624.tiff     1024x683                 X-ray burster illustration
ngc7252.tiff     512x512     WF/PC        NGC 7252 galaxy
odellcoll.tiff   557x406                  Orion Nebula
oria.tiff        680x524                  Orion Nebula
orib.tiff        803x603                  Orion Nebula
oric.tiff        1142x858                 Orion Nebula
oricomp.tiff     1600x1600                Orion Nebula
rosat5.tiff      285x340     ROSAT        NGC 2300 galaxies
saturn.tiff      546x492     WF/PC        Saturn
 
-- 
 
  						Zolt
  						[email protected]

    "The visions we present to our children shape the future.  It matters
  what those visions are." - Carl Sagan

CONTACT:  Ray Villard, STScI               FOR RELEASE:  September 30, 1993
          (410) 338-4514
	                                   PRESS RELEASE NO.: STScI-PR93-21
          Dr. Francesco Paresce, ESA, STScI
          (410) 338-4823



               HUBBLE SEES GAS SHELL AROUND NOVA CYGNI 1992

NASA's Hubble Space Telescope (HST) has given astronomers their earliest 
look at a rapidly ballooning bubble of gas blasted off a star.  The shell 
surrounds Nova Cygni 1992, which erupted February 19, 1992. 

A nova is a thermonuclear explosion that occurs on the surface of a white
dwarf star in a double star system.  Nova Cygni 1992 was one of the 
brightest novae in 20 years, reaching naked-eye visibility for a brief 
period.

Hubble Space Telescope's high resolution provides a unique opportunity to 
understand the nova mechanism, according to Dr. Francesco Paresce of the 
European Space Agency and the Space Telescope Science Institute.  "This is 
the first time we've been able to separate the white dwarf star from the 
ejecta so early in the nova event," he says.

Hubble, because of its high resolution, has "arrived at the scene of the 
crime" much earlier than ground based telescopes could have, according to 
Paresce.  (This shell will not be resolved from the ground for at least 
another five years.)  The shell is so young it still contains a record of 
the initial conditions of the explosion, he explains.  This will allow 
astronomers to construct the history of the nova explosion.

By the time the shell can be resolved with ground based telescopes, it 
will have been deformed and chemically contaminated by passing through 
other material around the star.  "The HST observations provide a unique 
opportunity to study the 'pristine' envelope of gas ejected by the 
explosion," Paresce explains. 

The HST image, taken with the European Space Agency's Faint Object 
Camera (FOC), reveals a remarkably circular yet slightly lumpy ring-like
structure.  The ring is the edge of a bubble of hot gas.  The shell is 
only 37 billion miles across, or 400 times the diameter of the Solar System.
A beam of light could cross the shell in less than 2-1/2 days.  By knowing
the shell's diameter, as calculated from a comparison between its angular 
size and it expansion velocity (as measured from ground-based observations),
astronomers can measure precisely the distance to Nova Cygni, which turns 
out to be 10,430 light-years. 

A striking relic of the explosion is an unusual bar-like structure across 
the middle of the ring. It might mark the edge-on plane of the orbits of 
the two members of the binary system, astronomers think.  A large amount of
gas stirred-up along the plane would make the shell denser in the plane of
the orbit of the double star.   An alternative possibility is that the bar 
is produced by twin jets of gas ejected from the star and spanning the 
distance between the shell and the star.


A nova occurs in a double star system where one member is a normal star 
and the other is a white dwarf, a compact corpse of the core of a 
Sun-like star that has dimensions the size of Earth.  The compact and 
gravitationally powerful white dwarf pulls material from its stellar
companion.  This material accumulates on the white dwarf's surface until
pressures and temperatures increase to the stage where thermonuclear 
reactions take place.  

The entire white dwarf's surface explodes as a gigantic hydrogen bomb.  A 
nova releases as much energy as our Sun produces in 1,000 years.  As the 
expanding shell of hot gas envelopes both stars, they continue to orbit 
inside it.  This should produce a thick disk of gas created through the
"eggbeater" motion of the two stars, according to astronomers.  The bar in
the Nova Cygni 1992 image may be the relic of the this event.

Shells around older novae, seen by ground-based telescopes, are deformed
by passage through interstellar space, and are faint and tenuous.  HST 
observations will be able to trace the expansion of the shell to a much 
earlier time in the history of a nova.

Watching the evolution of the shell also will reveal how heavy elements, 
processed in the star's envelope, are ejected back into space.  Such 
explosions enrich space with elements such as oxygen, carbon, and silicon
that are the fundamental building blocks for new generations of planets 
and presumably life. 



                                 ********

The Space Telescope Science Institute is operated by the Association of 
Universities for Research in Astronomy, Inc. (AURA) for NASA, under 
contract with the Goddard Space Flight Center, Greenbelt, MD.  The 
Hubble Space Telescope is a project of international cooperation between 
NASA and the European Space Agency (ESA).




  **********************************************************************

PHOTO CAPTION  STScI-PR93-21          FOR RELEASE: September 30, 1993      

                     GAS SHELL AROUND NOVA CYGNI 1992

A NASA Hubble Space Telescope (HST) image of a rapidly ballooning bubble 
of gas blasted off a star.  The shell surrounds Nova Cygni 1992, which 
erupted on February 19, 1992.  The shell is so young it still contains a 
record of the initial conditions of the explosion. 

The HST image was taken in ultraviolet light with the European Space 
Agency's Faint Object Camera (FOC) on May 31, 1993, 467 days after the 
explosion.  The FOC reveals a remarkably circular yet slightly lumpy 
ring-like structure.  The ring is the edge of the bubble's shell of hot 
gas.  The shell is only 37 billion miles across, or 400 times the 
diameter of the solar system.  A beam of light could cross the shell 
in less than 2-1/2 days.  

A striking relic of the explosion is an unusual bar-like structure across 
the middle of the ring. It might mark the edge-on plane of the orbits of 
the two members of the binary star system that triggered the nova.  An 
alternative possibility is that the bar is produced by twin jets of gas
ejected from the star and spanning the distance between the shell and 
the star.

A nova is a thermonuclear explosion that occurs on the surface of a 
white dwarf star in a double star system. 

By knowing the shell's diameter, as calculated from a comparison between 
its angular size and it expansion velocity (as measured from ground-based
observations) astronomers can precisely measure the distance to Nova Cygni,
which turns out to be 10,430 light-years.  Nova Cygni is located in the 
summer constellation Cygnus. 

       Credit: Francesco Paresce, ESA/STScI and NASA 

RE: Note 612.316

>A nova is a thermonuclear explosion that occurs on the surface of a white
>dwarf star in a double star system.

Gee, then what do you call thermonuclear explosions of other kinds of stars,
or of white dwarfs in non-binary (e.g., single or triple) systems? Or don't
these other configurations ever explode? (Later passages in the posting sort of
imply this, but that doesn't sound right.)

>The shell is 
>only 37 billion miles across, or 400 times the diameter of the Solar System.

Gee, I didn't know that the Solar System was only 92,500,000 miles across!
Sounds suspiciously like 1 AU, rather than the diameter of the solar system
(whatever the definition of that might be). 
						-- Tom

Hmmm...I think that case where a star that is LARGER than that which will
collapse to a white dwarf runs out of H2 and explodes is called a supernova.
It may be that the only way a smaller star can explode is under the conditions
specified.  I think a large star that runs out turns into a red giant.

I'm pulling this out of some very deep memories, so take it for what it is
worth...

Burns

re deep memory......

I thought supernova was from stars over the critical mass (sheesh, was it
something like 11 solar masses??? this is real rusty) run their life cycle.

And it has to be that many solar masses when the, what is it oxygen? is all
burnt up.  If mass is syphoned off by a companion (or some other reason), no
supernova.

I don't believe that a smaller star explodes in a supernova.

A nova is, again, from deep memory, normal matter, accreated on a white dwarf
that reaches the critical point.  (This type of explosion could probably also
happen with a neutron star???)  Since it is not a black hole, the white dwarf
serves to compress the notmal matter to the point of ignition, which sets off
the blast.  My understanding of theory is that nova's can reoccur, whereas
supernova's arte one time deals.

Tony

    re .-1 .-2
    
    The errors aluded occur all the time, what the scientist releases to
    the press and what the press releases to the public are only vaguely
    related to each other ... its called  PRESS RELATIVISM ... (-;
    
    What seems to have happened is that the reporter compressed a larger
    report, and took a few short cuts in unknown territory, with the given
    results.
    
    When I catch these errors in areas that are familiar to me, it always
    makes me nervous thinking of all the garbage I must have swalloded in
    other less familiar areas.
    
    In any case, 37 Billion miles IS 2.28 light days wich is ALMOST 400
    AU (the distance between the Earth and the Sun)  and ONLY 5.5 times
    the solar system diameter.
    
    And so on ... 
    		Gil

From: [email protected] (UPI)
Newsgroups: clari.tw.space,clari.local.florida,clari.tw.electronics
Subject: Hughes, Perkin-Elmer settle Hubble Space Telescope lawsuit
Copyright: 1993 by UPI, R
Date: Tue, 5 Oct 93 4:22:47 PDT

	DANBURY, Conn. (UPI) -- Hughes Aircraft Co. and Perkin-Elmer Corp.
agreed Monday to pay the U.S. government $25 million to settle a lawsuit
over a manufacturing flaw in the Hubble Space Telescope.
	NASA discovered a problem with the Hubble's mirror soon after
launching the telescope as part of the space shuttle program.
	Astronomers had expected Hubble to produce some of the best photos
ever of celestial objects, but the flaw seriously reduced the
telescope's usefulness.
	However, NASA astronauts plan to try to fix the Hubble during a
December shuttle mission.
	On Monday, Perkin-Elmer, which built the telescope, said it will pay
the government $15 million cash and take a $15 million charge against
earnings in order to avoid a protracted, costly legal battle with the
government.
	``Perkin-Elmer firmly believes that it acted responsibly in
accordance with NASA's procedures during the manufacture of the Hubble
Telescope mirror and that a lawsuit would have been completely
unwarranted,'' company Chairman and Chief Executive Gaynor Kelley said.
	``However, we determined that it would be contrary to Perkin-Elmer's
best interest to even attempt to match the seemingly limitless resources
of government agencies,'' he said.
	Perkin-Elmer sold the unit that manufactured the Hubble's mirror to
Hughes in 1989, shortly before NASA launched the telescope into space.
	Hughes, which took over the Hubble contract after the launch, agreed
Monday to forgo $3.5 million of on-orbit fees remaining on that pact,
and to reduce feess for future Hubble contract work by about $6.5
million.
	Meanwhile, Perkin-Elmer announced Monday that the U.S. Tax Court has
upheld the company's pricing practices with respect to its Puerto Rican
operations.
	The Puerto Rican tax case inolved treatment of transactions between
1975 and 1981.
	Perkin-Elmer said the tax court has set aside the government's
interpretations and found the company acted properly.
--
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RE: <<< Note 612.321 by PRAGMA::GRIFFIN "Dave Griffin" >>>

>This, and all articles in the clari.* news hierarchy, are Copyright 1993 
>by the wire service or information provider, and licensed to ClariNet 
>Communications Corp. for distribution. Except for articles in the 
>biz.clarinet.sample newsgroup, only paid subscribers may access these 
>articles. Any unauthorized access, reproduction or transmission is strictly 
>prohibited. 

Gee, is this re-posting OK?
						-- Tom

re: -.1

I was under the impression that all information sent through the internet
is deemed public domain.  Paid services such as the clari.*.* newsgroups
might be different, tho...

- jeff

You can forward clairnet articles to anyone within digital (including
notesfiles).  You just can't send them outside of digital with clarinet's
approval.

This has been covered before....

In addition to what Matt stated in .324, I believe we also cannot have
some automatic extraction tool (e.g., I cannot build something that takes
every article from clari.tw.space and post it here).   All repostings are
kept within Digital and I (or whoever) does them manually (a few mouse
clicks, but it isn't a program).    This keeps us well within the usage
rights for the clari newsgroups.


- dave

[From the September 1993 (Vol. 10 No.2) issue of SPACE TELESCOPE SCIENCE 
INSTITUTE NEWSLETTER.  Explanations to certain astronomical terms are provided.]

HOT HST OBSERVATIONS: COMET SHOEMAKER-LEVY 9 (1993E) AND SUPERNOVA SN 1993J
By Nino Panagia

Starting with this issue, we will provide concise descriptions of recent 
observations of objects which, to our arbitrary judgement, are particularly 
interesting either scientifically or for their technical challenge and can be 
illustrative of the exceptional results that HST achieves.  Our selection for 
the time are Comet Shoemaker-Levy and SN 1993J.

Comet Shoemaker-Levy (1993e)

Both the Planetary Camera and the Faint Object Spectrograph were 
used to make observations of the Comet Shoemaker-Levy 9 (a.k.a., 
Comet 1993e) on July 1st.  This comet broke into many fragments during 
a close approach to the planet Jupiter in July 1992, but was not 
discovered until late March 1993.  Ground-based observations revealed 
that the fragments are currently strung out in a line about one arcminute 
in length.  [NOTE: 1 arcminute = the angular size of a quarter seen from 
79 meters away.]  The string of fragments was imaged with the Planetary 
Camera, and spectra were obtained with the FOS G270H grating and 
Red Side detector.  [NOTE: The Red Side detector is one of the 2 Digicon 
detectors that is more sensitive to longer (red) wavelengths.  The grating 
used is one of 8 gratings available on the Faint Object Spectrograph.]  
The images looked great and should provide important information on 
the sizes of the fragments.  The spectroscopic observations were made to 
search for the UV bands of OH [hydroxyl], as the latter provide a sensitive 
indicator of any ice sublimation occuring in the system.  The comet 
fragments are predicted to collide with Jupiter, near its South Temperate 
Belt [The dark belt to the south of the Great Red Spot], in July 1994.  
Although the fragments will probably hit the planet surface on its dark 
side, the fast rotation of Jupiter will rapidly bring the impact zone into 
view.  The study of this event will hopefully provide a wealth of 
information on the structure and properties of the Jovian atmosphere.

SN 1993J

Observations of SN 1993J, the brightest supernova in the Northern 
Hemisphere since 1937, successfully tested HST's capabilities to make 
target-of-opportunity observations on short notice.  The difficulty of 
scheduling these observations was increased because they had to be 
inserted into the schedule just when the telescope was recovering from a 
safemode episode (the SADE-1 shut-off).  Discovered on 28 March 1993, 
SN 1993J was first observed with the Goddard High Resolution 
Spectrograph (GHRS) on April 8-9 to measure interstellar lines of MgI 
and MgII, and on April 15 with the Faint Object Spectrograph (FOS) to 
measure the overall spectrum of the supernova in the range 1600-4800 
Angstrom [NOTE: Mg = Magnesium.  MgI = neutral magnesium, MgII = 
magnesium atoms stripped of one electron.  1 Angstrom = 0.1 nanometer].  
Both observations were successful, providing spectra of high and medium 
resolution of excellent quality.  Chris Blades, PI [Principal Investigator] 
of the first program reports "... some fabulous absorption line profiles.  
We are looking at the interstellar MgII doublet and MgI in gas from our 
galactic halo and the parent galaxy using the supernova simply as a 
background probe."

CONTACT:  Ray Villard, STScI  FOR RELEASE: October 18, 1993
          (410) 338-4514
                              PRESS RELEASE NO.: STScI-PR93-22
          Dr. Harold Weaver
          (410) 338-5004


       HUBBLE INVESTIGATES COMET ON A COLLISION COURSE WITH JUPITER

NASA's Hubble Space Telescope has provided the most detailed look
yet at the comet hurtling toward a July 1994 collision with the
giant planet Jupiter.

Hubble's high resolution shows that the approximately 20 objects
that comprise comet P/Shoemaker-Levy 9 -- giving it the
resemblance of a "string of pearls" -- are much smaller than
originally estimated from observations with ground-based
telescopes.  According to Dr. Harold Weaver of the Space
Telescope Science Institute (STScI) Baltimore, MD, the Hubble
observations show that the cometary nuclei are probably no bigger
than three miles across, as opposed to earlier estimates of nine
miles.

The new Hubble data show that the impacts will unleash only
1/10th to 1/100th as much energy as thought previously.  However,
even with these new size estimates, the total energy of the
collisions will be equivalent to 100 million megatons of TNT --
10,000 times the total destructive power of the world's nuclear
arsenal (at the peak of the Cold War).  The impacts will be
comparable in strength to the collision of a large asteroid or
comet with Earth 65 million years ago. This latter cosmic catastrophe
is suspected to have caused the extinction of the dinosaurs and 
hundreds of other species between the Cretaceous and Tertiary ages. 

Weaver and a team of co-investigators are announcing their
analysis of the Hubble observation at the 25th annual meeting of
the Division for Planetary Sciences of the American Astronomical
Society held in Boulder, Colorado.

Since the comet's discovery last March, there have been widely
varying estimates of how energetic the collisions with Jupiter
will be. The force of the collision depends not only on the speed
of the impacting bodies, but their size as well.

Measuring the sizes of the nuclei is very difficult because each
nucleus is surrounded by a haze of dust, called a coma.  "Most of
the light being observed is due to scattering by dust in the
coma," Weaver says.  Relative to ground-based images, the Hubble
image provides improved contrast between the nuclei and their
comae, thereby allowing a better estimate for the sizes. 
However, "even the current Hubble image does not allow a clear
separation of nucleus and coma, so its size estimates are still
probably only upper limits to the true nuclear sizes," according
to Weaver.

Fortunately, the definitive answer might be available soon. 
During the December Hubble Servicing Mission a new camera called
WFPC-2, (Wide Field and Planetary Camera 2) with corrective
optics to compensate for aberration in Hubble's primary mirror,
will be installed on the telescope. "The Hubble repair should
provide images with much better contrast than the current images,
and if the nuclei are close to the sizes we now think they are,
then they should really pop out in the new Hubble images," Weaver
says.

Hubble's sharp resolution shows that one bright knot in the comet
stream is really four fragments close together.  Two of the
pieces have an apparent separation of only 700 miles.  The Hubble
image also shows that most of the visible nuclei have comparable
sizes.  Weaver says that the close match in size among the chunks
suggests they might be the primordial "building blocks" of
comets. According to calculations, the parent comet broke apart
when it passed close to Jupiter in July 1992.  "Jupiter's gravity
might have disassembled the comet back into the primordial
objects, called planetesimals, that were present when our Sun
formed 4.5 billion years ago," Weaver says.  "However, since the
current Hubble observations cannot detect nuclei much smaller
than about 2 km, the size distribution of the planetesimals is
still indeterminate.  Once Hubble's optics are fixed, we should
get a better handle on the range of sizes within the planetesimal
population."

Though commonly referred to as a comet, some astronomers think
P/Shoemaker-Levy 9 might be an asteroid. In this case, it would
have come from the asteroid belt between the orbits of Jupiter
and Mars, rather than from a hypothetical comet belt beyond
Pluto's orbit.  However, no one has ever seen an asteroid break
apart so it is difficult to predict how asteroids should behave
under these circumstances.  Likewise, since there are few
detailed studies of comets as far away as Jupiter (1/2 billion
miles), it's hard to know how a comet should behave at Jupiter's
distance. 

At Jupiter's distance the comet's surface is so cold that the
sublimation rate of water ice is very small. "On the other hand,
the breakup of the comet may have released an unusually large
number of icy grains, exposing such a large surface area to the
sun that the sublimation might become detectable," Weaver says. 
"Also, there are probably substances present that are more
volatile than water ice."

Weaver's team took spectra near the brightest fragment to search
for molecules that might have been released from subliming ice. 
This would provide strong evidence that P/Shoemaker-Levy 9 is a
comet, not an asteroid.  Spectroscopic observations made with
Hubble Faint Object Spectrograph failed to find hydroxyl
molecules that would be a clear indicator of cometary origin.

Another way to address this mystery is by watching the evolution
of the surrounding coma. A cometary origin would be likely if the
coma is continually replenished by gas streaming off the
fragments, since comets are more icy than asteroids.  However, if
the coma simply spreads out, eventually completely disappearing,
the coma might just be dust from a broken-up asteroid. The
current Hubble image shows that the coma is apparently not
continually being replenished, but more observations are needed
to monitor the coma development further. 

The Jupiter collision is expected to occur over a six-day period
around July 21, 1994.  The effect of the impact will depend not
only on the size and velocity of the cometary nuclei, but also
their composition and structure.  Comets are very porous and,
thus, might break up high in the atmosphere.  For example, on
June 30, 1908 a 160-foot (50-meter) wide cometary nucleus or
stony meteor is suspected to have disintegrated in Earth's
atmosphere at an altitude of five miles (8 km).  The resulting
explosion leveled hundreds of thousands of acres of forest in
Siberia's Tunguska River Valley, Russia. 

The Jupiter impacts could potentially produce spectacular
phenomena in the giant planet's multicolor cloud tops.  The
plummeting comet nuclei would turn into gigantic versions of
meteors or "shooting stars."  Each 100-mile wide, blue-white
fireball would blow a hole in Jupiter's atmosphere the size of
Texas.  Although the impacts are predicted to occur on Jupiter's
far side (not observable from Earth), it's likely that the
effects on the atmosphere still will be visible as the impact
zone rotates into the Earth's view.  (Jupiter's rotation rate is
9 hours, 50 minutes.) 

The Hubble telescope is expected to be a key player during next
year's encounter, although there are no definite observing plans
yet.  Due to its low-level of scattered light and high angular
resolution, the Hubble should be able to observe the comet even
when the glare of Jupiter prevents further ground-based
observations.  After the impact, the Hubble images should show
details in Jupiter's atmosphere that are unattainable by any
other means.

The comet was discovered last March by Dr. Carolyn Shoemaker of
Northern Arizona University, Dr. Eugene Shoemaker of the U.S.
Geological Survey, and veteran amateur comet observer David Levy. 
The HST observing team consists of these three people, Weaver,
and 15 others from a variety of institutions.


                                 ********

The Space Telescope Science Institute is operated by the
Association of Universities for Research in Astronomy, Inc.
(AURA) for NASA, under contract with the Goddard Space Flight
Center, Greenbelt, MD.  The Hubble Space Telescope is a project
of international cooperation between NASA and the European Space
Agency (ESA).




*****************************************************************



PHOTO CAPTION  STScI-PR93-22a           FOR RELEASE: October 18, 1993      

                 HUBBLE VIEWS THE "STRING OF PEARLS COMET"

[left]
An image of comet P/Shoemaker-Levy 9 taken on 30 March 1993 with
the Spacewatch Camera of the University of Arizona.  Although not
clearly visible in this image, the bright "streak" near the
center contains many individual nuclei and their associated comae
and tails.  In addition, light scattered from fine dust particles
can be seen extending for large distances beyond the region of
the streak.

credit: Dr. J.V. Scotti, University of Arizona

[center]
An image taken by the Planetary Camera of the Hubble Space
Telescope on July 1, 1993 that shows the streak region in much
greater detail.  The appearance of this broken-up comet is
reminiscent of a "string of pearls." 

[right]
This is an enlargement of the HST image in the region of the
brightest nucleus.  By looking carefully, one can tell that the
"brightest nucleus" near the center of the frame is actually a
group of at least four separate pieces that are blurred together
when observed at poorer resolution.  The HST images allow for the
best separation of the individual nuclei and their comae, which
results in a better estimate of the nuclear sizes.

The amount of energy unleashed into the Jovian atmosphere in July
1994 depends on the nuclear sizes, so these HST images provide
important information for those seeking to predict the effects of
the collisions on Jupiter's atmosphere.

Comet P/Shoemaker-Levy 9 (1993e) made a close approach to Jupiter
in the summer of 1992 and was broken into multiple pieces as a
result of tidal forces from that giant planet.  The remaining
pieces are expected to plunge into Jupiter's atmosphere during a
5.6-day period of time centered on 21 July 1994.

credit:   Dr. H. A. Weaver and Mr. T. E. Smith, STScI 
          NASA

                             *****************




PHOTO CAPTION  STScI-PR93-22b           FOR RELEASE: October 18, 1993      

          HUBBLE TELESCOPE IMAGE OF THE "STRING OF PEARLS COMET" 

A NASA Hubble Space Telescope image of approximately 20 objects
that comprise comet P/Shoemaker-Levy 9, giving it the resemblance
of a "string of pearls."  The comet is hurtling toward a July
1994 collision with the giant planet Jupiter.

Hubble's high resolution shows that the comet's nuclei are much
smaller than originally estimated from observations with
ground-based telescopes.  The Hubble observations show that the
nuclei are probably less than three miles (5 km) across, as
opposed to earlier estimates of nine miles (14 km).

The amount of energy unleashed into the Jovian atmosphere in July
1994 depends on the nuclear sizes, so these HST images provide
important information for those seeking to predict the effects of
the collisions on Jupiter's atmosphere.

This image was taken with the Wide Field and Planetary Camera
(WFPC), in PC mode, on July 1, 1993. 

credit:   Dr. H. A. Weaver and Mr. T. E. Smith, STScI
          NASA


                             *****************




PHOTO CAPTION  STScI-PR93-22c           FOR RELEASE: October 18, 1993      

       HUBBLE CLOSE-UP OF BRIGHT NUCLEUS IN COMET P/SHOEMAKER-LEVY 9

This is an enlargement of a NASA Hubble Space Telescope image of
the "brightest nucleus" in a string of approximately 20 objects
that comprise comet P/Shoemaker-Levy 9.  The  comet is hurtling
toward a July 1994 collision with the giant planet Jupiter.

Hubble's high resolution shows that this bright region is
actually a group of at least four separate pieces.  The HST
images allow for the best separation of the individual nuclei and
their surrounding halo of dust (comae), which results in a better
estimate of the nuclear sizes.

The image was taken with the Wide Field and Planetary Camera
(WFPC), in PC mode, on July 1, 1993.  The Hubble observations
show that the cometary nuclei are probably less than three miles
(5 km) across, as opposed to earlier estimates of nine miles (14
km).

The new Hubble data show that the impacts will unleash only
1/10th to 1/100th as much energy as thought previously.  However,
even with these new size estimates, the total energy of the July
1994 collisions will be equivalent to 100 million megatons of
TNT.

credit:   Dr. H. A. Weaver and Mr. T. E. Smith, STScI
          NASA

European Space Agency
Press Information Note Nr. 12-93
Paris, France					14 June 1993

FIVE EVA SESSIONS: THE MOST COMPLEX SHUTTLE MISSION EVER TO REPAIR THE HUBBLE 
SPACE TELESCOPE

In the opinion of scientists themselves, the ESA/NASA Hubble Space 
Telescope is producing really exceptional results that no other instrument 
in existence can match.  Since the start of its mission in April 1990 it has 
been observing planets, stars and galaxies, giving us a greatly improved 
overall view of the cosmos.  The recently published image of a violent 
young star is a further example of the contribution the HST is making to 
modern astrophysics.  And yet, in December this year, a crew of seven 
astronauts, including ESA's Claude Nicollier from Switzerland, will be 
taking off on board the US Shuttle to go to work on the HST.  Why is this?  
Why repair an instrument that is already established as the world's best in 
its category?

First, because this mission was planned from the outset.  The impression 
may have been received that the astronauts' rendezvous with the Hubble 
satellite is an emergency mission to correct the optical flaw in the 
Telescope's primary mirror.  But that is a misapprehension, as the facts 
make clear:

"Since design work started on it, back in the 1970s, the Space Telescope 
has always been intended to remain in orbit for an operational lifetime of 
15 years.  That is a relatively long time.  Routine service calls by 
astronauts have therefore always been one of the key features of the 
mission.  A series of rendezvous, using the Shuttle, are scheduled at 
intervals of three years on average.  This year's is the first, with more to 
come in 1996/97, 2000, and so on", explains Derek Eaton, HST Project 
Manager for ESA.

The structure of the Hubble Telescope is therefore designed to facilitate 
the tasks to be performed by astronauts during EVA.  It comprises 49 
standardised, readily accessible and replaceable modules.  On its outer 
surface, it has about a hundred footholds and handholds for use by visiting 
"space mechanics".

These servicing missions have therefore always been an integral part of 
the Space Telescope programme, to fulfil two purposes: to modernise the 
scientific instrumentation and to replace any elements found to be 
defective.  The original plan for the first rendezvous was to replace the 
American Wide Field/Planetary Camera (designed in about 1975) with a 
more advanced model (1990 technology).  After the discovery of the 
Telescope's defective vision and a vibration problem on the European 
solar arrays, it was decided to take the opportunity to deal with these two 
anomalies in addition.  Corrective optics will be installed, and the solar 
arrays will be replaced sooner than planned.

Secondly, repairs have indeed become necessary.  After three years in 
orbit, the Telescope has suffered considerable wear, although this was 
expected.  It has lost three of the original six gyroscopes, leaving it with 
the minimum number required for pointing control.  Of the three fine 
guidance sensors, which serve to "lock on" celestial objects, one is out of 
action and the other two are still operating.  One of the two electronic 
systems for control of solar array deployment is also showing signs of 
wear.  The deterioration that has occured so far is as yet having little effect
on the programme's overall performance.  All the satellite's sensitive 
elements were installed in duplicate.  But in the case of the gyroscopes, 
for instance, there are no useable spares left.  In other words, restoring 
redundancy on board is becoming a matter of urgency, to make sure that 
the mission can continue with maximum reliability and effectiveness.

The third and last justification for December's rendezvous is that it will in 
fact be very beneficial scientifically.  "The Space Telescope is admittedly 
suffering from impaired vision.  It cannot see as clearly or as far as 
expected.  Nevertheless, it has demonstrated its extraordinary capabilities.  
It is producing first-class observations day after day, in a limited portion of
the universe.  Any improvement is therefore worthwhile, and installation of 
the corrective optics is certainly going to be a paying proposition.  The 
slightest progress -- even if it does not quite attain the standards originally
expected -- will enable us to make significant strides in the quality and 
quantity of data and ultimately in our knowledge of the cosmos," maintains 
Duccio Macchetto, ESA's man at the Space Telescope Science Institute in 
Baltimore, USA, who for 15 years led the European team in charge of 
developing the Faint Object Camera.  "Moreover," he adds, "the scientific 
instrument that will benefit most from the corrective optics will be the FOC, 
designed and built by European scientists to explore the most distant 
regions of the universe."

With hindsight, the Space Telescope programme approach can be seen to 
have been fully justified.  Without this crewed mission, it would have been 
impossible to correct the two manufacturing faults discovered after the 
launch.  Worse still, with normal wear and tear on the satellite, the 
programme might have run into serious difficulties within the next few 
years.  Instead, the human presence in space has brought just the right 
measure of flexibility to one of the most ambitious space science 
programmes of these closing years of the century, while at the same time 
actually enabling the payload to be modernised in line with technological 
progress on Earth.

The US Shuttle Endeavour will therefore be lifting off in December with 
clearly defined objectives, with a two-tier priority ranking:

Top priority:
	Change the solar arrays
	Replace the Wide Field/Planetary Camera (WF/PC)
	Install the corrective optics (COSTAR)
	Change some of the gyroscopes
Second priority (according to time remaining available):
	Repair a scientific instrument (high-resolution spectrograph)
	Increase the capacity of the on-board computer
	Carry out other minor repairs (magnetometer, etc.)

The new solar arrays are being delivered this month by ESA to NASA.  
WPFC II is more sensitive than the original camera, especially in the 
ultraviolet.  But COSTAR (Corrective Optics Space Telescope Axial 
Replacement), the Space Telescope's "spectacles", is bound to be the 
piece de resistance of next December's mission.

COSTAR is the optical system that is to be installed to compensate for the 
aberration in the Telescope's primary mirror.  The principle according to 
which it operates was worked out by a group of American and European 
scientists, and it was then selected from among a total of 28 solutions 
proposed.  It is the size of a telephone booth and will be taking the space 
occupied by the scientific instrument of which least use has been made, 
the high-speed photometer.  It will make corrections for the three 
remaining "axial" instruments, the European Faint Object Camera, the 
high-resolution spectrograph and the Faint Object Spectrograph.  WFPC 
II, a "radial" instrument, will contain its own compensation mechanism.

COSTAR is a complex device.  It differs from spectacles in that optical 
correction is by reflective mirrors rather than transparent glass lenses.  It 
continas eight tiny aspherical mirrors, the size of a fingernail.  The surface 
of each has been polished to a precision of one millionth of a millimetre, 
which means that the residual surface variation are no higher than a stack 
of about 10 atoms!  These mirrors will be held by moveable fingers at the 
end of a deployable arm and placed, with extraordinary accuracy and 
lightness of touch, in front of the instruments to be corrected.

Europe will be playing a substantial role in the repair mission.  As Roger 
Bonnet, Director of ESA's Science Programme, points out: "First, we have 
had a 15% share in the Space Telescope programme from the outset.  
That is a considerable scientific and financial input on Europe's part.  So 
we have a direct interest in improvement of this unique satellite's 
performance.  Sceondly, our participation includes an extremely important 
scientific instrument, the Faint Object Camera, which is severely affected 
by the Telescope's blurred vision.  So it is very much in out interests for 
this problem to be rectified.  We have another direct involvement in that 
the flexible solar arrays, whicha are affecting the pointing of the Telescope 
and have to be changed, were made in Europe, under the Agency's 
responsibility.  Finally, Europe will be represented on board the Shuttle by 
the ESA astronaut Claude Nicollier, who was the obvious choice for this 
role, not only on account of his expertise as an astronaut (he is a specialist 
in operation of the robot arm) but because he is also an astronomer."

With its very heavy workload, the STS-61 mission promises to be one of 
the most sophisticated in the Shuttle's history.  It is scheduled to last 11 
days, and crew members will be making at least five EVA sorties, an all-
time record.  Even the spectacular Intelsat retrieval in May 1992 required 
only four.  In fact, to be on the safe side, NASA is allowing for two 
additional sorties, if neded, so that the total number might be as high as 
seven.

In order to bring off this exploit without too much fatigue, the five 
extravehicular working sessions will be shared between two alternating 
shifts of two astronauts.

The crew will have seven members, all of them with previous experience: 
the Commander Richard Covey (aged 47, 3 missions), the Co-Pilot 
Kenneth Bowersox (aged 37, 1 flight), the Mission Specialist Claude 
Nicollier (aged 49, 1 flight) and the four "space walkers", the Payload 
Specialist Story Musgrave (aged 58, 4 flights) and the Mission Specialists 
Tom Ackers (aged 42, 2 flights), Kathryn Thornton (aged 41, 2 flights) and 
Jeffrey Hoffman (aged 49, 3 flights).

Although he will not be engaged in the EVA work, Claude Nicollier will 
have the vital role of operating the Shuttle's robot arm while two of his 
colleagues are outside, repairing the Space Telescope.

The detailed mission schedule has not yet been finalised.  It will be 
published by ESA in October.  However, we do already know that the first 
two days will be taken up by the launch and the various checks to be 
carried out on arrival in orbit.  On the third day, Claude Nicollier will 
capture the HST with the robot arm.  The next five days will be devoted to 
the five EVA sessions, during which the solar arrays, the WFPC and the 
gyroscopes will be replaced, COSTAR will be installed, and so on.  The 
HST will be released on the ninth day, the tenth will be taken up by the 
checks to be carried out prior to reentry, and the eleventh will see 
Endeavour's return to Earth.

The most distinctive feature of the mission is the large number of critical 
operations to be carried out in space.  Considerable allowance therefore 
has to be made for the unforeseen.  The mission schedule will be planned 
with this in mind, seeking to maximise the chances of success while 
retaining the flexibility needed in order to react to circumstances as they 
arise.  The astronauts themselves are currently engaged in intensive 
underwater training, at the space centres in Houston, Texas, and 
Huntsville, Alabama.  As Story Musgrave commented recently, "The one 
thing we know for sure is that there will be surprises.  The mission is not 
going to pass off exactly as planned.  We realise that and so we are 
examining all the possible contingencies."

This Information Note is the second in a series of six that ESA is issuing to 
the press to provide details of the STS-61 mission scheduled for launch on 
2 December 1993 to carry out servicing and repairs on the HST, 
explaining the importance of this mission, the aims pursued and the 
preparations being made.  The first Note (1) gave an account of the 
scientific breakthroughs made by Hubble.  This one (2) describes the 
servicing mission itself in general terms.  The subjects of those still to 
come will be: (3) ESA's participation in the HST programme, (4) the 
astronaut Claude Nicollier, (5) the detailed STS-61 mission schedule and 
(6) the Space Telesocpe's future through to the next century.

[From the September 1993 (Vol. 10 No. 2) issue of SPACE TELESCOPE SCIENCE 
INSTITUTE NEWSLETTER.]

HST SERVICING MISSION UPDATE AND OVERVIEW OF SERVICING MISSION OBSERVATORY 
VERIFICATION (SMOV)
By Carl Biagetti

The first HST servicing mission is still on schedule with the Shuttle 
launch slated for 2 December 1993, at 4:30 AM, EST.  Within the first two 
days of the mission, the HST will be readied, through a combination of 
on-board commands and ground commands, for capture by the Shuttle.  
At approximately 4 AM on Dec. 4, the Shuttle is scheduled to grapple and 
berth the HST.  Starting on day three, the astronauts will begin a series of 
five EVAs, one per day, during which all the HST upgrades and repairs 
will be accomplished.  As of this writing, the principal activities planned 
for each EVA are as follows:

EVA 1	Rate Sensing Unit (RSU) 2 (Gyros 3 & 4)
	RSU 3 (Gyros 5 & 6)
	Magnetic Sensing System (MSS) 1 (Magnetometer 1)

EVA 2	Solar Array II

EVA 3	Wide Field Planetary Camera (WFPC) 2
	Goddard High Resolution Spectrograph (GHRS) Repair Kit

EVA 4	COSTAR
	Electronic Control Units (ECUs) 1 & 3

EVA 5	Solar Array Drive Electronics unit 1 (SADE-1)
	MSS 2
	Coprocessor
	Fuse Plug

At the end of EVA 5, the new Solar Arrays will be deployed.  The current 
schedule calls for HST to be unberthed at 1:30 AM on Dec. 10.  At 4:00 
AM, the Aperture Door is opened, followed by release of HST at 5:20 AM, 
a little more than eight days after launch.

The Servicing Mission Observatory Verification (SMOV) begins upon 
release of HST from the Shuttle.  Planned for execution over an 
estimated three-month period, the SMOV has as its primary objectives 
the recommissioning of the HST for the resumption of science operations 
in as short a time as possible, and for the publication of Early Release 
Observations (EROs) to demonstrate the improvement in telescope 
performance.

The SMOV period is divided into three phases: 1) the Real-Time 
Command Phase, 2) the Health & Safety Stored Program Command 
(SPC) Phase, and 3) the Science Mission Specification (SMS) 
Command Phase.

The Real-Time Command Phase is the shortest of the three phases, 
having an expected duration of less than two days.  It begins upon HST 
release from the Shuttle orbiter and consists of those basic operations 
that normally constitute HST recovery from PSEA Safemode 
[Pointing/Safemode Electronics Assembly].  These operations include, 
among other things, initialization of the spacecraft, attitude determination 
and transition to on-board attitude control, gyro bias updates, and uplink 
of the new ephemeris.

Once the first phase of SMOV is completed, the Health & Safety SPC 
Load, enabling the initiation of High Gain Antenna (HGA) tracking.  The 
Health & Safety SPC Phase is planned to last about two days, and 
provides for the completion of the flight software transition to support 
normal science activities.  The third and longest of the SMOV phases is 
the SMS Command Phase.  This phase consists of an extensive series of 
engineering activation and check-out of the serviced systems, including 
WFPC2, COSTAR and the COSTAR-corrected SIs [Science Instruments], 
i.e., FOC [Faint Object Camera], FOS [Faint Object Spectrograph], and 
GHRS.  The HST OTA [Optical Telescope Assembly] is then collimated, 
the COSTAR Deployable Optical Bench (DOB) is deployed, and a 
coordinated program for optical alignment of all the SIs is begun.  As 
each SI achieves fine alignment, a calibration program designed to 
recommission the SIs as quickly as possible for resumption of science 
operations is undertaken.

At appropriate times after SI alignment and during the calibration phase, 
Early Release Observations (EROs) will be performed in order to provide 
images, and possibly spectra, of scientifically interesting targets that 
clearly demonstrate to the public, the media, and to the scientific 
community the dramatic improvement in HST performance.

The entire SMOV program consists of several dozen interrelated 
activities that have been designed and documented in a joint effort by 
NASA/GSFC, the ST ScI, PIs [Principal Investigators] and IDTs 
[Instrument Development Teams].  The ST ScI SMOV preparation team is 
currently processing 82 proposals for execution during the SMOV period 
which, under current estimates, will require thirteen weeks for 
completion.

    re .-2
    
    Will they be bringing the High Speed Photometer back to Earth? Does
    anyone know of any plans to reuse it, if so?

    What is it about gyroscopes that makes them so susceptible to failure?
    
      John

Ball bearings...


- dave  :-)

    Quick question
    
    
    Has the hubble's orbit declined significantly since initial launch. If
    so would the shuttle be able to boost it to a higher orbit? I expect
    based on my reading that there is not scheduled orbital correction
    maneuver planned for this mission. 
    
    Will there be future boosts on future missions or is the altitude of
    the hubble sufficient to last the 15 planned years.
    
    regards.
    
    Roger

    re .332
    
    What's the reason that they don't use Ring Laser Gyros (RLG)?

I've wondered that myself.   They do have some intrinsic reliability properties
that makes them very useful.

A few things come to mind (being somewhat ignorant of gyroscope technology):

  1. They aren't as accurate as the mechanical ones (though this seems
     a bit unlikely).  They are less mature.

  2. The design for HST is rather old.  Laser gyros were either too new or
     too inaccurate during the design phase.

  3. The gyros that they have are so customized to the task that replacing
     them with a different technology was too expensive.

[I have a saying on my white board (attributed to Voltaire):
    le mieux est l�nnemi du bien
 which roughly translates to "the best is the enemy of the good (enough)".
 This is a engineering maxim that if the component meets the design specs,
 then there's no reason to put in a better one -- if you ever want to
 finish a project.   The specs on the mechanical gyros should have provided
 them with sufficient lifetime.  20/20 hindsight doesn't count.]


- dave

p.s. As my "smiley" may have indicated, I honest don't know for sure that the
gyros are mechanical.  I vaguely remember something about vibration and overtemp
problems with them, so I extrapolated.

>>>    
>>>    What's the reason that they don't use Ring Laser Gyros (RLG)?
>>>

Because these won't provide any external torque. The use the gyros to
physically point the scope, not as feedback.

erik

RE Hubble's decaying orbit.

  Originally it was placed as high as they could get it with the shuttle. Since
they are capable of taking it on board and bring it home, boosting it to a
higher orbit shouldn't be a problem.

  I haven't heard, but will they be placing it into the hold for the repairs
or are they going to leave it outside the Shuttle while they work on it? If
they were going to bring it on board, moving to a higher orbit would be simple,
just fly the shuttle higher before releasing it again.

  George

    	The November issue of SKY & TELESCOPE has two detailed articles
    on the HST repair.  The plan is to place HST on one end in the cargo
    bay while the astronauts do their tasks.
    
    	Larry
                    

    re .336
    
    Erik, can you explain further? Like my initialsake, I don't know much
    about gyro technology. Are you saying that an RLG can detect rotation
    but not do anything about it whereas a mechanical gyroscope can be used
    both to monitor and to control rotation?
    
    re .various
    
    *Is* Hubble's orbit decaying? I haven't seen any postings from NASA to
    that effect. In 636.66 it talks about *GRO*'s orbit needing a reboost
    (from 345km->450km).

RE: Hubble's orbital decay

The orbit has decayed (as all orbits this low do), but I don't know by how
much. In two years, I'm pretty sure the decay is on the order of miles, but
perhaps not many tens of miles.

Just because the Shuttle can enclose the device doesn't mean the Shuttle can
boost it's orbit enough. Depends on the mass of the device and on the amount
of boost required. The OMS engines don't have enough fuel to boost something
as massive as the Hubble 100 miles or more, I bet. So if the decay was left to
accumulate significantly, the Shuttle wouldn't be capable of providing the
required boost. If the decay had been miles or tens of miles, the Shuttle
probably is capable of the required boost.
						-- Tom

  The Shuttle should be able to boost Hubble to it's original height with no
problem. 

  It was a Shuttle that flew the thing to it's original height. That means that
the Shuttle took off and flew from the pad to the original height carrying all
the weight. 

  It seems that if a Shuttle were to take off and fly up to Hubble's current
height with only spare parts, there would be extra weight capacity available for
extra fuel. Loading it on board and flying it up to it's original height should
be easy, in fact they should be able to take it higher. 

  George

Re: .341:  I'm really lousy at orbital mechanics, but I'll point out that the
shuttle brought HST to its original orbit with the SSMEs.  They didn't
start out at a lower orbit and raise it with the OMS.

That aside... (and continuing with my armchair speculation):

The shuttle has changed orbit heights before (a couple of missions had them
all over the place).   I don't think the additional bulk of the HST is
so substantial that they couldn't do a couple of OMS burns to create a
transfer orbit and then circularize at a significant new height...

- dave

    In a few of the shuttle missions, to hear it they are flying all
    over the place between here and the moon. 
    
    But the reality is, that the Shuttle's OMS delta-velocity capacity
    is minor. And the Shuttle can't alter its orbit that much. Enough
    to catch a satellite or a station that is already in almost in the 
    same orbit and that is about it.
    
    You can't just do much  with the couple hundred meters per second
    of total delta-velocity available.
    
    Gil

  I'm not an expert in orbital mechanics either, but it still should work.

  Yes, the shuttle used it's main engines and SSME's to get into low orbit with
Hubble then it used it's OMS system to move up to the final orbit. They will
also use the SSME's and SRBs to launch this mission and it seems that if they
needed to they could carry extra OMS fuel instead of HUBBLE. 

  Anyway, if HUBBLE is scheduled to fly for 15 years then it must be possible
to raise it's orbit unless the orbital decay at that altitude is so minimal
that it won't matter.

  George

RE: <<< Note 612.344 by HELIX::MAIEWSKI >>>

>  Yes, the shuttle used it's main engines and SSME's to get into low orbit with
>Hubble then it used it's OMS system to move up to the final orbit. 

Not correct. The SSMEs and the fuel in the ET were used to achieve most of the
final Hubble orbit. The OMS burn(s) on the deployment mission were "routine"
circularization maneuvers.

>They will
>also use the SSME's and SRBs to launch this mission and it seems that if they
>needed to they could carry extra OMS fuel instead of HUBBLE. 

There is unused payload mass available to carry fuel, but no place to put it.
I haven't heard of developments to construct payload-bay fuel tanks.

>  Anyway, if HUBBLE is scheduled to fly for 15 years then it must be possible
>to raise it's orbit unless the orbital decay at that altitude is so minimal
>that it won't matter.

Certainly, re-boosts must be planned for. The shuttle presumably can do it for
small re-boosts at a time (e.g., every few years or so). But if one waited to
re-boost until the HST orbit decayed from its launch ~360nm orbit way down to
routine shuttle orbits of 160mn to 200nm, I don't think the shuttle could
perform the reboot. That's all I'm saying.
						-- Tom

>>       <<< Note 612.339 by AUSSIE::GARSON "Hotel Garson: No Vacancies" >>>
>>
>>    re .336
>>    
>>    Erik, can you explain further? Like my initialsake, I don't know much
>>    about gyro technology. Are you saying that an RLG can detect rotation
>>    but not do anything about it whereas a mechanical gyroscope can be used
>>    both to monitor and to control rotation?
>>    

	Ok, firstly, I'm working on a couple of assumptions about my
	understanding of the laser gyros, and possible flawed memory.. ;-)

	If you take a spinning mechanical gyro, and push against it, it
	will "push back". This is the property that is used for navigation 
	in a 2 or 3 dimentual space. You measure how much the gyro has 
	"pushed back", and you have the data to figure out where you moved.
	
	IN the HST, they use this property so that if you want to move 
	the scope in a particular direction, they push against the gyro,
	the gyro will want to remain stationary, so as a result, the scope 
	moves. 	(This also puts load on the bearings.. ;-)

	A lazer gyro, if my understanding and memory is correct, has no 
	moving parts. It works because light travels in a straight line, 
	and fixed speed. So, if you launch a photon at a target, and then 
	move the target, before the photon arrives, it will land offcenter 
	of the target. So, you can look at how far off center, and for 
	how long, to figure out how far you moved.

	So, if you have a laser gyro, and push it over, it will fall over
	and tell you very precicly, how far, at what speed...... it moved. 
	It won't push back :-(

Now if anyone else has a better understaning of this, feel free to shoot 
photons (But not torpedo types) at me. ;-)

erik

        RE .346  MECHANICAL GYROS

    That's pretty close.  Another example of a mechanical gyro is that
    that is the principle that keeps a bicycle or motorcycle upright.
    If you think of the tires as basically giant gyros.

    I remember an experiment/demonstration that we used to do back in
    high school.  We'd take a bar stool that would rotate and a bicycle
    tire/rim with handles attached to the axle (gyro).  Sit on the bar 
    stool and hold the "gyro" out in front of you with the tire in the 
    vertical position.  Start the "gyro" spinning.  Then as you try to 
    tilt the gyro from side to side you will get a lateral force that will 
    push you one direction or the other.


    fred();

Well, I'm not sure the gyros are used to *move* the HST.

If I recall how HST works, there are two pointing mechanisms, and two
positioning mechanisms:


  Pointing
    Mode        Position Sensor      Position Actuator
 ----------     ---------------     -------------------------
  Course         Gyroscopes           Momentum Wheels

   Fine          FGS (Optical)        Electromagnetic Torquers


Slews to particular coordinates are done with the gyroscopes and momentum
wheels.  That gives them a course lock on a target.

The FGS (Fine Guidance Sensors) then acquire a guide star and take over for
fine tuning and holding the HST during exposures, etc.  Those fine adjustments
are made by bouncing electromagnets off the magnesphere.

I'll try to verify this over the weekend...  I think I have a description
in my library somewhere..


- dave

I reviewed some HST status reports from back in 91, just to see if I could
glean some useful data.

[Sigh... I may have to recant .348, but I'll wait till I've got better proof.
 The gyros may be used for both purposes (guidance and movement).  I KNOW that
 the gyros are definitely used for attitude sensing.  I'm not sure if they
 also are used to actually move the observatory.]


Anyway, gyros #4 and #6 failed rather early in the flight.  The contractors
for the gyros, Bendix/Allied Signal, and a review board determined that the
problem was electrical in nature: "open wire bond" (whatever that means --
could mean "broken wire").  The "open wire bonds" were in different areas
for the two gyros.

So, for at least two of the gyros, the electronics and not the mechanical
systems seem to be the problem-causers  (so much for my offhand comment about
ball bearings).


- dave

This is extracted from a 1991 HST newsletter...  I've swapped the
order of the articles for clarity.  The first one describes the gyros
a bit, and the second goes into the failures and implications.

- dave

-------------------------
 HST Gyros

        Since its launch on April 24, 1990, HST has experienced failures of
two of its six gyros, the mechanisms used to point and stabilize the
telescope (see previous article). Because there are only four gyros left,
and the telescope needs at least three to operate, it is natural to ask
what the gyros are and how they work.

        The principle of the gyros is similar to that of a child's toy
gyroscope: the inertia of a spinning mass provides a restoring force that
counters any displacement of its spin axis. In the HST case, the gyros have
only one degree of freedom-the spin axis is supported by only one gimbal.
In the accompanying diagram, rotation about the input axis causes the
gimbal to precess about the output axis. (You can see why this happens if
you remember that the angular-momentum vector is parallel to the spin
axis.)

        What our engineers call a "gyro" is actually composed of some very
sophisticated electronics, which together with the above hardware form a
feedback system that works in concert with the Fine Guidance Sensors and
Fixed Head Star Trackers to point the telescope. These electronic
"reference" gyros are called Rate Gyro Assemblies. They are made up of a
Rate Sensing Unit and an Electronic Control Unit, both of which can be
replaced in orbit. There are three of these RGAs, each containing two gyros
(x- and y-axes) whose input axes are skewed with respect to the telescope's
axes. This offset means that three-dimensional control of the spacecraft
can be maintained with any configuration of three or four gyros. That is,
if the six gyros were aligned exactly with the telescope axes, and two on
the same axis malfunctioned, then only the two remaining axes could be
controlled.

        The gyros are located on the equipment shelf near the back of the
telescope, in order to isolate them from vibrations caused by the reaction
wheels and the high-gain antenna. The reaction wheels are four flywheels,
each with mass of about 45 kg, which control and modify spacecraft attitude
based on RGA information processed and interpreted by the Control Law
Software. The reaction wheels are also mounted with angled spin axes to
provide redundancy.

        There is a separate set of backup gyros called the Retrieval Mode
Gyro Assembly, which are used if fewer than three main gyros are available.
There is no direct ground communication with the RMGA-it is enabled by the
Power Distribution Unit. The telescope is then safely kept in "hardware sun
point" mode with the aperture door closed, but of course it cannot then be
used for scientific observations.

-Pete Reppert

---------------------
HST Spacecraft Operational Status

[... other details omitted ...]

        While it had essentially no effect on on-going scientific
observations, there was another gyro failure (this time of gyro #4) this
past summer. This gyro behaved intermittently for several weeks, and then
apparently failed completely. At the time of the initial failure, HST was
operating in its normal four-gyro configuration. The failure resulted in a
saturated output from the gyro, e.g., it indicated the maximum possible
rotation rate. The flight software recognized the erroneous input
immediately and took the gyro out of the control loop, falling back to a
three-gyro configuration. The saturated condition lasted for about 80
seconds, after which the gyro output returned to normal although the flight
software remained in the three- gyro configuration.

        After investigation, we returned gyro #4 to the control loop. A
very similar event occurred again three days later, except that the gyro
stayed saturated for 10 minutes. Finally, a week later, the gyro failed
with a saturated output and remained saturated.

        Analysis indicates that the likely cause of the failure was a
failed wire bond in one of the hybrid circuits in the gyro electronics
package. Although in a different circuit, it is a similar failure to the
gyro #6 failure that occurred last December.

        Gyro #4 was left running, although its output obviously was not
used to control the telescope. In late October, it unsaturated again, and
produced reasonable data for a period of about a week. The HST Operations
Control Center at GSFC is continuing to monitor its performance.

        Following the failure of gyro #4, we turned on the last spare gyro,
gyro #1, and after calibration it was placed into the control loop,
returning HST to a four-gyro configuration. The four-gyro configuration
allows the flight software to perform checks on gyro data and detect
failures, as it had done with gyro #4. Science operations are also possible
with only three gyros, as indeed was done for a period this summer while
the problems were being diagnosed. Vehicle pointing performance is
essentially the same in the three- gyro configuration as in the four-gyro
configuration.

        These events led to a review of the flight software "sanity" checks
that are available when operating in three-gyro mode and possible failure
modes. As a result, modifications are being made to the flight software
that will provide more robust checks of gyro performance while in
three-gyro mode. A zero-gyro safemode that is designed to maintain the
health of the spacecraft has also been added, but (obviously) it cannot
carry out a science program.

        In addition to the gyro #4 failure, there have been two other gyro
anomalies since the last Newsletter. Gyro #5 has shown an increase in
operating current, but there has been no change in its performance. Gyro #1
has had one short episode of increased noise. These anomalies are distinct
from those exhibited by gyros #4 and #6 as they were failing. Both
situations are being analyzed, but at this time they are not believed to be
precursors of further failures.

-Rodger Doxsey

I was a wire bonder while in school many years ago.

You sit at a microscope and put gold wires from pad to pad WITHIN a chip 
package before it is sealed. The wires are ultrasonicly scrubbed into the 
surface and the wire is cut off with a flame on the final up stroke 
leaving a tail. Later, these tails are pulled manually on another line 
and the wires lifted to avoid shorts and check the integrity of the 
bonds on both ends. G forces and vibration can cause these bonds to fail 
since few of the chips are "potted" (filled with an insulator)

They were just automating this 15 years ago when I moved on to software

Failure of one of these bonds would lift a wire and cause an "open" in the 
circuit.

Aha...so I think .350 is saying that there are two separate sets of gadgets: 
Rate Gyros, which are used to sense motion, and reaction wheels, which are used
to change motion.  And it is the rate gyros that are causing trouble.

That implies that one could use Laser Ring Gyros or some new technology, except
that that would not help the kinds of problems that the Hubble rate gyros are
experiencing.

Interesting stuff...thanks for digging it up.

Burns

>> Rate Gyros, which are used to sense motion, and reaction wheels, which are used
                                                   ^^^^

	These are simply "big gyros" with more mass to push against. ;-)

All very interesting...

erik

>>> Rate Gyros, which are used to sense motion, and reaction wheels, which are
>used
>                                                   ^^^^
>
>	These are simply "big gyros" with more mass to push against. ;-)
>

Sure, and much less sophisticated sensors, and more powerful actuators, and
I would guess that they are designed to work over a wider variety of speeds of
the wheel.

Burns

Article: 15725
Newsgroups: sci.space.shuttle
From: [email protected] (David Wicks)
Subject: 'Day One' Hubble Feature
Sender: [email protected] (netnews admin account)
Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
Date: Tue, 2 Nov 93 20:41:31 GMT
 
Producers from the ABC News program 'Day One' were spotted in Houston
this morning preparing a feature on the Hubble repair mission for the 
magazine show.  They interviewed STS-61 astronauts Jeff Hoffman and
Kathy Thornton about their roles on the repair effort, and captured
footage of the JSC Manipulator Development Facility, where RMS opera-
tors train for upcoming missions by maneuvering full-sized helium-
filled balloons with a hydraulic replica of the Shuttle's robot arm.
 
This morning, the Hubble balloon was mounted in the Orbiter payload
bay mockup, and RMS operator Claude Nicollier practiced maneuvering
the RMS with an EVA astronaut on a Manipulator Foot Restraint.  (Yes,
there's even a helium-filled astronaut balloon.) The Hoffman inter-
view was conducted next to the MDF.
 
When asked when the feature would air, the producer allowed that she
did not know for certain, since it was up to "New York" to decide,
but figured it would be in December or January.
 
STS-61 is scheduled for late-November or early December.  If "New
York" doesn't want to show the feature before the mission, perhaps
it means they want to see the results before making their final edits.
(But that's just my suspicious mind.)
 
-----------------------
 
Interview Trivia  (A Propos of nothing, but interesting to me):
 
The sound system for this interview was, well, "neat".  Interviewer
and subject wore cordless microphones which transmitted audio to the
sound man, who set the level and whatever else.  He then broadcast
the mixed audio to the camera, where a cordless receiver fed the audio
into the camera audio input.  All transmitters are on separate fre-
quencies, of course.
 
To film interviewer and subject in a 'casual' stroll, the cameraman
sat in a chair on a small, wheeled pallet pulled along by an assistant.
Low-tech, but effective.
 
*****************************************************************************
* David Wicks ([email protected])   | ". . . that rare first draft of    *
* Lockheed Engineering & Sciences Co.  |  the Constitution with the word    *
* Houston, Texas                       |  'suckers' in it." - W. SMITHERS   *
*****************************************************************************

From:	US1RMC::"[email protected]"  4-NOV-1993 00:58:32.78
To:	Multiple recipients of list <[email protected]>
CC:	
Subj:	PLANETARIANS-PEN digest 23

Contents:
HST Servicing Mission ([email protected])

----------------------------------------------------------------------

Date: Wed, 3 Nov 1993 11:12:35 -0800
From: [email protected]
Subject: HST Servicing Mission

This is a paper given at the GLPA conference by Rob Landis
of the Space Telescope Science Institute. It was posted on
sci.astro.planetarium in 4 parts.

>From [email protected] Wed Nov  3 06:52:23 1993
Date: Wed, 3 Nov 93 09:52:16 EST
From: Robert Landis <[email protected]>
To: [email protected]
Subject: HST Servicing Mission/GLPA 1993 Paper

Hi Alan,

I tht. you might be interested in this paper.  I presented
it at the GLPA conference in Dayton a couple weeks ago.  If you'd
like to post to sci.astro.planetarium -- by all means, please do.

If folks in the planetarium world would like slides and video (which
accompanied my paper at GLPA), they need to write the E/PA office on
letterhead and send a blank VHS cassette to: 

        Educational/Public Affairs Office
        Space Telescope Science Institute
        3700 San Martin Drive,
        Baltimore, MD  21218
        ATT'N.:  Janet Morrissey

Janet's email address is:  [email protected]

I (we) would be very interested in knowing how many folks out there in the
planetarium world will cover the mission.

Best,

++Rob
*****************************************************
       Covering the HST Servicing Mission from Your Planetarium

Rob Landis
Space Telescope Science Institute/Science Planning Branch
3700 San Martin Drive, Homewood Campus
Baltimore, MD  21218
email:  [email protected] on INTERNET
        73237,3222 on Compu$erve

ABSTRACT:  The Hubble Space Telescope servicing mission is
the most complex shuttle mission ever attempted.  The most
experienced crew launched aboard the space shuttle will
make an unprecedented five planned EVAs to replace failing
hardware to restore the Hubble to its full scientific poten-
tial.  Planetaria are among the HST project's biggest cheer-
leaders.  HST is a national resource and NASA Select tele-
vision may provide planetarium patrons a ringside seat to
the high stakes, high profile nature of the STS-61
[Endeavour] flight.  This paper suggests a possible background
program and day-by-day coverage planetaria may wish to share
with the public and media during the servicing mission.


        The author and Steve Fentress (Strasenburgh Planetarium)
had remarkable success covering the Voyager 2/Neptune encounter
during August 1989 using existing NASA video and still images.
No special effects were needed -- nor used -- to bring Voyager 2's
odyssey to the Upstate New York community.  A similar program
could just as easily be implemented to cover the first servicing
mission to the Hubble Space Telescope.

                                Background

        Since its preliminary inception in 1973, HST was designed
to be a different type of mission for NASA -- a permanent space-
based observatory.  To accomplish this goal and protect the spacecraft
against instrument and equipment failures, NASA had always planned on
regular servicing missions.  Hubble has special grapple fixtures,
76 handholds, and stabilized in all three axes -- quite unlike the
Intelsat 6 communications satellite (serviced and reboosted on STS-49),
which was not designed to be serviced in orbit.

        When originally planned in 1979, the Large Space Telescope
program called for return to Earth, refurbishment, and relaunch
every 5 years, with on-orbit servicing every 2.5 years.  Hardware
lifetime and reliability requirements were based on that 2.5-year
interval between servicing missions.  In 1985, contamination and
structural loading concerns associated with return to Earth aboard
the shuttle eliminated the concept of ground return from the program.
NASA decided that on-orbit servicing might be adequate to maintain
HST for its 15-year design life.  A three year cycle of on-orbit
servicing was adopted, and servicing misisons are planned for
December 1993, March 1997, mid-1999, and mid-2002.  Contingency
flights could still be added to the shuttle manifest to perform
specific tasks that cannot wait for the next regularly scheduled
servicing mission (and/or required tasks that were not completed
on a given servicing mission).

        The first servicing mission to the Hubble Space Telescope
is the most intensively complex undertaking in manned spaceflight
since the Apollo moon landings.  An unprecedented five EVAs are
planned for STS-61.  The high drama of human spaceflight and man-
kind's quest for knowledge may be a sure-fire means of identifying
your facility as an interface and focal point between the public/media
and NASA.

        Shortly after launch (24 April 1990) and during the ensuing
science and orbital verfication phase, astronomers and engineers dis-
covered two major problems with HST:

(1) the now well-publicized spherical aberration of the primary mirror,
and (2) the telescope "jittered" twice per orbit as it crossed Earth's
day/night terminator.  The jitter is due to the thermal expansion/con-
traction of solar panels during each day/night crossing.  This unwanted
motion further limits the amount of observing time HST can provide.

        During the fall of 1990, NASA organized a panel of scientists
and engineers to explore possibilities of restoring Hubble's optical
system to its full potential.  Several possible solutions were entertained;
the simplest being COSTAR (Corrective Optical Space Telescope Axial Re-
placement).

        Hubble has five (5) main science instruments:  the High Speed
Photometer (HSP), the Goddard High Resolution Spectrograph (GHRS), the
Faint Object Camera (FOC), the Wide Field/Planetary Camera (WF/PC),
and the Faint Object Spectrograph (FOS).  COSTAR will displace the HSP.

                            Servicing Mission Tasks

        Crew and spacecraft safety being foremost in any spaceflight,
the first servicing mission has three primary goals:  (1) demonstrate
that extensive on-orbit servicing of a complex spacecraft is practical,
(2) restore Hubble's science capabilities with corrective hardware back
to the original expectations for sensitivity and quantitative accuracy,
and (3) restore redundancy to the spacecraft subsystems.  In order of pri-
ority, the most significant hardware to be installed is:

        o Replacement of the solar arrays.  The European Space Agency
          (ESA) has developed a new pair of arrays which should eliminate
          the jitter as the telescope crosses the day/night terminator.

        o COSTAR installation; jointly developed by GSFC and Ball
          Corporation.  Essentially, COSTAR is a deployable optical
          bench with a series of attached corrective mirrors.  After
          the astronauts install COSTAR and verify electrical connections,
          ground controllers will actuate the bench, extending it into
          the telescope assembly in front of the GHRS, FOC, and FOS.  (This
          will be done through a series of steps throughout SMOV).

        o WF/PC2 installation; developed by JPL; has its own corrective
          optics. More photometrically stable CCDs with better S/N ratio.

        o RSU (gyroscope) replacement.  Of the six gyroscopes aboard HST,
          three have failed.  One more RSU failure would temporarily halt
          science operations until new software is written to point the
          telescope on the two remaining gyroscopes.

        o Magnetometer replacement; one is faulty and will probably fail
          soon.  The other is suspect.  Two new Schonstedt magnetometers
          have been ordered.  (The magnetometers are not specifically de-
          signed for changeout.)


        There are also several secondary tasks for STS-61's crew.  In order,
these secondary priorities include:

        o Solar Array Drive Electronics (SADE) replacement.  This is a new
          addition to the list of tasks following the SADE-1 failure in March
          1993.  SADE controls the solar panel motions of the spacecraft.
          As a precautionary measure, the number of solar panel motions are
          currently limited on the spacecraft (SADE-2 is operating on a
          back-up system).

        o Computer augmentation (addition of a co-processor).  One of the
          Rockwell DF-224 general purpose computers has failed.  Endeavour
          will carry a second DF-224, but the preferred repair is to place
          a co-processor in a test slot.  The latter task is simpler and
          increases computer memory.

        o GHRS Repair Kit.  The power supply to the HRS is suspect.
          Astronauts will attach an electronics box to a handrail to
          cross-strap two separate electronics systems to either side
          of the spacecraft.


                                Launch and Rendezvous

        As of this writing, STS-61 remains on schedule for a 2 December
1993 launch.  Rendezvous is slated for near the end of Flight Day 2.
HST will first appear "star-like" to the Endeavour crew.  As the shuttle
approaches, Hubble's cylindrical telescope assembly and solar arrays
become obvious.  Before berthing HST, the crew will examine the telescope
for damage.  Of particular concern is the solar arrays.  The crew will
attempt to photograph the jitter phenomenon as HST crosses the day-night
terminator.

        Under the control of an astronaut, the shuttle's Remote Manipulator
System (RMS) arm will grasp one of two grapple fixtures on HST.  The tele-
scope will be lowered onto a special support structure at the aft end of
the payload bay.  At that moment, the HST will be attached to an umbilical
to feed off of the shuttle's power.

        After rendevous and berthing, Endeavour's crew will secure the cabin
and sleep.  Unlike previous shuttle missions with seven crewmembers [where
the crew was split into two working shifts], STS-61 will not implement split
work/sleep shifts.  The philosophy for the first servicing mission is to keep
all crew on the same wake/sleep cycle in the event a substitution or backup
is required at the last minute.  Flight Day 3 marks the first of five EVAs.

                                Scheduled EVAs

        All EVA crewmembers for STS-61 (Musgrave, Hoffman, Thornton, Akers)
are crosstrained on one another's tasks should last-minute rescheduling of
activities be required.  Further, one backup astronaut (Harbaugh) is fully
trained in all tasks should one of the other EVA crew be unable to fly.

        Although replacement of the solar arrays is top priority, this is
currently scheduled for the second day of EVA work (Flight Day 4).  Instead,
the first EVA crew will first prepare the cargo bay for the five days of EVAs.
Two gyroscopes (RSUs) and a magnetometer are to be replaced.  Before returning
to the shuttle cabin, the first EVA crew will prepare the telescope for solar
array replacements.

        On Flight Day 5, which equates to EVA Day 2, the solar array replace-
ments are on the docket.  Once the first array is properly in place, the
"turntable" structure supporting HST will rotate 180! for installation of
the second solar array.  This task -- replacement of the solar arrays -- is
scheduled for the entire six-hour period allotted for this EVA.

        The changeout of WF/PC1 with WF/PC2 is slated for the following day,
and, if time permits a new relay box will be installed on the GHRS.  This
relay will provide an alternate power source for the short wavelength detector.

        EVA Day 4 begins with the installation of COSTAR, which will displace
the HSP.  Assuming a nominal installation [and a successful release of Hubble],
COSTAR's optical bench will deploy and be aligned, tested, etc., over a period
of ~ 13 weeks.  COSTAR should restore HST to its original optical specification.

Before returning to the shuttle cabin, two electronic control units for the
gyroscope system will be installed.

        The final scheduled day of EVA activities include:  (1) replacing SADE,
(2) replacement of the second magnetometer, (3) installation of fuse plugs for
the gyroscopes, and (4) adding a co-processor to HST's main computer.  Closure
for the final EVA will take about an hour.  The final EVA crew will pick up
loose ends, stow tools, and prepare the cargo bay for re-entry.

        A timeline schedule of the events described above appears later in this
paper. Please note it is tentative and only current as of 15 September 1993.
The schedule could easily change between now and launch, or even after launch.
Although no three-man EVAs are planned, such an EVA could be implemented.

        SMOV (Servicing Mission Observatory Verification) begins on Flight
Day 9  once controllers at Goddard give the "go for release" signal to the
Endeavour crew.  The SMOV period consists of spacecraft recommissioning,
WF/PC2 engineering and decontamination, engineering checkout of COSTAR,
science instrument calibrations, and more.  SMOV will probably end in
March 1994.  The first early release observations should be available
during the tail-end of SMOV.


                        Future Servicing Missions to Hubble

        Although the next servicing mission is tentatively slated for
March 1997, Shea et al. (1993) has recommended that NASA shelve plans for
regular service calls and maintain contingency "place holder" missions in
the shuttle schedule to be used for HST as needed.  The EVA workload for
STS-61 has grown 25% (Asker, 1993) since the mission was first defined.
Depending upon what Endeavour's crew accomplishes, NASA is considering a
second HST servicing mission 3 to 9 months after STS-61, instead of 1997.
NASA will make this decision regarding an immediate revisit upon the con-
clusion of the end-to-end simulations and the final flight readiness review
in late October 1993.

        In the meantime, the next planned servicing mission to Hubble is
on the manifest for March 1997.  On that mission, two new instruments may
be installed on HST:  the Near-Infrared Camera and Multi-Object Spectrometer
(NICMOS) and the Space Telescope Imaging Spectrograph (STIS).  Of course,
both will displace existing instruments (probably the FOS and GHRS) but will
extend HST's infrared capabilities.  For the 1999 servicing mission, the
Advanced Camera (AC) may be installed to replace the then-aging FOC.  One
last servicing mission to Hubble is tentatively planned for 2002.

          Why Might Planetaria Want to Cover the First Servicing Mission?

        With the profusion of satellite dishes (plus, many cable television
companies carry the NASA Select signal) and video within the planetarium
communitiy, the servicing mission affords the opportunity to identify a
facility as a space science information center for fast-breaking news.
Granted, many of the lay-public may have access to NASA Select, but no
one to intrepret the NASA jargon or explain the planned (and contingent)
activities.  Undoubtedly, the planetarium is a unique environment to showcase
this topical space event provided staff members are familiar with and keep
abreast of the mission.  The footage that is recorded during the flight may
easily be utilized  in future productions (i.e., space shuttle, HST, space
station, etc.).

        Although it requires work and planning for contingencies, it is easy
to fill a 50-minute program with a multi-media background video and slides,
current days' work/accomplishments, and a question and answer session.  As
with the case with covering the Voyager 2/Neptune encounter, many patrons
felt like a part of the space program.

        Planetaria may wish to consider using a local astronomer who is a GO
on the HST project and staff to help interpret the NASA jargon.  For example,
Susan Simkin is an astronomy professor at Michigan State University, home of
Abrams Planetarium; Doug Duncan, a former STScI planning scientist and also
a GO, is now at the Adler; Jim Secosky of Rochester, New York is one of the
few amateur astronomers to use Hubble (of course, Rochester is home to
Strasenburgh).

        Covering STS-61 also gives planetaria the opportunity to renew
interest in space science amongst patrons.  Despite the problems and equipments
HST has experienced, it continues to produce excellent science and make new
astronomical discoveries daily.  The planetarium environment is a unique
conduit to share these discoveries and the servicing mission with its patrons.

Author's note:  The slides and video segment which complemented this paper are
available via STScI's Education/Public Affairs Office.  The slides have also
been donated to the GLPA Slide Bank.  Video may be obtained when requested in
writing on institutional letterhead by sending a blank VHS tape to the E/PA
Office, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD
21218.


Timeline for EVA activities has changed since this paper was first
written. The new timeline appears as Figure 1b.  This may change yet
again following a final flight readiness review in late-October 1993. 

                                Appendix

                        Hubble Space Telescope
                      First Servicing Mission Crew

Dick Covey      Commander               STS-51I, STS-26, STS-38

Ken Bowersox    Pilot                   STS-50

Story Musgrave  Payload Commander       STS-6, STS-51F, STS-33, STS-44

Claude NicollierMission Specialist      STS-46

Jeff Hoffman    Mission Specialist      STS-51D, STS-35, STS-46
                                        First unscheduled EVA on 51D

Tom Akers       Mission Specialist      STS-41, STS-49
                                        Two EVAs on STS-49:  Intelsat, ASEM

Kathy Thornton  Mission Specialist      STS-33, STS-49
                                        EVA STS-49:  ASEM

Greg Harbaugh   Mission Specialist      STS-54
                        [Backup]        EVA STS-54:  EVA Operations Evaluations


                        Space Shuttle EVA Training History

   Mission                      Water Tank Hours                  Description

STS-6                                   76              First shuttle EVA
STS-41B                                121              First MMU flight
STS-41C                                109              Solar Max repair
STS-41G                                 54              ORU refueling demo
STS-51A                                 67              Westar/Palapa retrieval
STS-51I                                 43              Syncom repair
STS-61B                                 59              Ease/access
STS-31                                  94              HST deployment
STS-37                                 182              GRO deployment
STS-49                                 238              Intelsat 
retrieval/repair
STS-61                                 394              First HST servicing 
mission

                HST:  STS-61/SM-1 Overview (as of 15 September 1993)

Activity                  Predicted Date/Time (EDT)     MET (dd:hr:min)

Launch                          2 December 1993/
                                4:30 AM                 00:00:00

Configure HST                   3 December 1993
 - NSSC-1  H&S SMS
        (end normal science)    4:30 AM                 01:00:00
 - Configure GHRS               5:00 AM                 01:00:30
 - Close Aperture Door          7:30 AM                 01:03:00

Begin Rendezvous Maneuvers
 - Orbiter Grapple HST          4 December 1993/
                                4:00 AM                 01:23:30
 - HST to external power        5:00 AM                 02:00:30

EVAs
 - EVA 1 begin (6 hours)        5 December 1993/
                                12:10 AM                02:19:40

 - EVA 2 begin (6 hours)        6 December 1993/
                                12:10 AM                03:19:40

 - EVA 3 begin (6 hours)        7 December 1993/
                                12:10 AM                04:19:40

        - WF/PC1 powerdown      1:10 AM                 04:20:40
        - WF/PC2 activation     2:30 AM                 04:22:00
        - GHRS powerdown        TBD
        - GHRS re-activation    TBD
        - WF/PC2 test           7:15 AM                 05:01:45

 - EVA 4 begin (6 hours)        8 December 1993/
                                12:10 AM                05:19:40
        - HSP powerdown 1:00 AM                         05:20:30
        - COSTAR activation     2:30 AM                 05:22:00
        - COSTAR test           6:30 AM                 06:02:10

 -EVA 5 begin (6 hours) 9 December 1993/
                                12:10 AM                06:19:40
      - Safe all SIs            ~2:40 AM                06:22:10
      - Recover SIs (not FOS)   end of EVA 5
      - Deploy solar arrays     5:30 AM                 07:01:00

Deploy HST (possible reboost)
 - Switch to internal power     10 December 1993/
                                1:00 AM                 07:20:30
 - Unberth HST                  1:30 AM                 07:21:30
 - HST release                  5:20 AM                 08:00:50

Orbiter landing                 13 December 1993/
                                2:30 AM                 10:22:00

STScI SMOV begins               13 December 1993/
                                3:30 PM                 11:11:00


[Sorry, no figures in email version of paper.]
FIGURE 1a:  Time line of EVA activities on STS-61.  Current as of 15 September
1993.  1b:  Time line of EVA activities as of 19 October
1993.  Courtesy GFSC.

FIGURE 2:  Diagram (to scale) shows 13-meter long HST berthed at the aft
end of shuttle cargo bay.  Depicts COSTAR removal from ORU. Courtesy Lockheed.

                                        Acronyms

COSTAR  Corrective Optics Space Telescope Axial Replacement

ESA  European Space Agency

EVA  Extravehicular Activity

FOC  Faint Object Camera

FOS  Faint Object Spectrograph

FGS  Fine Guidance Sensor

GO  General Observer (also Guest Observer)

GHRS  Goddard High Resolution Spectrograph, also referred to as HRS.

GTO  Guaranteed Time Observer

HSP  High Speed Photometer; to be displaced by COSTAR

HST  Hubble Space Telescope

JPL  Jet Propulsion Laboratory

NASA  National Aeronautics and Space Administration

NICMOS  Near-Infrared Camera and Multi-Object Spectrometer

ORU  Orbital Replaceable Unit

RSU  Rate-sensing unit (gyroscope)

SAA  South Atlantic Anomaly

SADE  Solar Array Drive Electronics

SMOV  Servicing Mission Observatory Verification

STIS  Space Telescope Imaging Spectrograph

STS-61  Space Transportation System; the first servicing mission is the 61st
shuttle mission on the manifest since the space shuttle first flew in 1981.

STScI  Space Telescope Science Institute.

WF/PC  (pronounced "wif-pik")  Wide Field/Planetary Camera

                        Acquiring the NASA Select Signal

NASA Select television is carried on GE Satcom F2R, transponder 13,
C-band, 72 deg West longitude, transponder frequency is 3960 MHz,
audio subcarrier is 68 MHz, vertical polarization.  Correct pointing
of your receiving dish is left as an exercise in spherical astronomy
for the user.

                                        References

Asker, J. R., "Hubble:  Risky, But Achievable,"  Aviation Week and
Space Technology, 138:40-41+ (1993).

Shea, J.F. et al., Report of the Task Force on the Hubble Space
Telescope Servicing Mission (1993).

------------------------------
End of Digest
************************

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From:	US1RMC::"[email protected]" "Mostly Harmless"  8-NOV-1993 12:16:16.53
To:	distribution:;@us1rmc.bb.dec.com 
CC:	
Subj:	HST Deep-Sky Survey Finds Interacting Galaxies in a Cluster

CONTACT:  Ray Villard, STScI     FOR RELEASE: November 8, 1993
          (410) 338-4514
                                 PRESS RELEASE NO.: STScI-PR93-23
          Dr. Richard Griffiths
          (410) 516-4194

               HUBBLE SPACE TELESCOPE DEEP-SKY SURVEY FINDS 
                     INTERACTING GALAXIES IN A CLUSTER

In one of the deepest celestial surveys yet made by NASA's Hubble
Space Telescope, astronomers have discovered a small group of
previously unknown,interacting galaxies estimated to be three
billion light-years away*. 

Hubble caught the galaxies in an early stage of evolution, and so
they offer new clues to developing a much clearer understanding
of how galaxies have changed over time.

Nearly half the galaxies appear to be merging with one another in
the Hubble image.  This suggests a very rapid evolution of
galaxies and clusters of galaxies over very short time spans,
according to astronomers.  These results might help improve
theories which predict that galaxies evolved faster than earlier
thought, perhaps due to the influence of dark matter -- invisible
or undetected mass pervading the universe. 

A galaxy is a city of stars that are held together by their
mutual gravitation. Galaxies are considered the basic building
blocks of the universe and HST's high resolution image reveals
that many early galaxies "building blocks" are in pairs. "In many
of the pairs, at least one galaxy is blue, which indicates that
star formation is under way at a high rate, possibly triggered by
interaction with the neighbor galaxy," says Dr. Richard Griffiths
of The Johns Hopkins University, Baltimore.  "Such mergers and
interactions may be the rule within galaxy clusters rather than
the exception."

"Though the largest galaxy in the image is about the size of our
own Milky Way galaxy, most of the galaxies detected are much
smaller than our own.  They might eventually merge to form the
many large galaxies that we see in the universe at the present
day," he says.

Over the past two years, Griffiths and colleagues at Johns
Hopkins University, with a team of astronomers in the U.S. and
Britain, have used the Hubble Space Telescope to carry out a
serendipitous survey of small areas of sky.  This is done with
the Wide Field Camera, which is used to take a picture of a piece
of sky close to a main target such as a quasar or galaxy that is
being observed by a different Hubble instrument.

The survey is one of several Key Projects using Hubble.  In
previous images the deep survey has uncovered remote and unusual
galaxies never before resolved by an optical telescope. HST's new
level of detail reveals a bizarre variety of shape and structure
in these distant galaxies, which only previously appeared as
fuzzy blobs from ground based telescopes.

*The distance to the largest galaxy in the image has been
measured by Prof. Rogier Windhorst and his group at Arizona State
University, using the Multi-Mirror Telescope in Arizona, operated
by the University of Arizona and the Smithsonian Institution.

                                 ********

The Space Telescope Science Institute is operated by the
Association of Universities for Research in Astronomy, Inc.
(AURA) for NASA, under contract with the Goddard Space Flight
Center, Greenbelt, MD.  The Hubble Space Telescope is a project
of international cooperation between NASA and the European Space
Agency (ESA).

******************************************************

PHOTO CAPTION  STScI-PR93-23a    FOR RELEASE: November 8, 1993    

HUBBLE SPACE TELESCOPE DEEP-SKY SURVEY FINDS INTERACTING GALAXIES
IN A CLUSTER

A NASA Hubble Space Telescope image of a previously unknown small
group of galaxies estimated to be three billion light-years away*.  
They existed when the universe was only about 80% its present age. 

HST's high resolution reveals that many appear to be interacting
and merging galaxies.  In many cases, at least one member of each
pair is blue in color, indicating active star formation, possibly
triggered by interaction with a neighbor galaxy.

The observations promise to eventually lead to a much clearer
understanding of galaxy evolution.

This image is part of a serendipitous sky survey which has been
conducted over the past two years by Prof. Richard Griffiths and
colleagues at Johns Hopkins University, with a team of
astronomers in the U.S. and Britain. 

The survey is one of several Key Projects for Hubble.  In
previous images, the deep survey has uncovered a bizarre variety
of shapes and structures in distant galaxies, which only
previously appeared as fuzzy blobs from ground based telescopes.

Technical Description

The left-hand frame is a composite "true-color" image taken by
Prof. Rogier Windhorst and colleagues of Arizona State
University, using the 90-inch telescope at Steward Observatory,
University of Arizona.  The right-hand frame is a "true-color"
composite of 9 images taken in visible and near infrared light
with the Wide Field Camera, in May 1993.  Each exposure was about
30 minutes long.  The field of view is 44 arc seconds across,
corresponding to a span of 600 thousand light-years at the
measured distance to the brightest galaxy in the image.  The
resolution is 0.1 arc seconds, about 10 times better than can be
routinely achieved from the ground.

credit:   Richard Griffiths, The Johns Hopkins University and NASA

*The distance to the largest galaxy in the image has been
measured by Prof. Rogier Windhorst and his group at Arizona State
University, using the Multi-Mirror Telescope in Arizona, operated
by the University of Arizona and the Smithsonian Institution.

              **********************************************

PHOTO CAPTION  STScI-PR93-23b    FOR RELEASE: November 8, 1993    

HUBBLE SPACE TELESCOPE DEEP-SKY SURVEY FINDS INTERACTING GALAXIES
IN A CLUSTER

A NASA Hubble Space Telescope image of a previously unknown small
group of galaxies estimated to be three billion light-years away*.  
They existed when the universe was only about 80% its present age. 

HST's high resolution reveals that many appear to be interacting
and merging galaxies.  In many cases, at least one member of each
pair is blue in color, indicating active star formation, possibly
triggered by interaction with a neighbor galaxy.

The observations promise to eventually lead to a much clearer
understanding of galaxy evolution.

This image is part of a serendipitous sky survey which has been
conducted over the past two years by Prof. Richard Griffiths and
colleagues at Johns Hopkins University, with a team of
astronomers in the U.S. and Britain. 

The survey is one of several Key Projects for Hubble.  In
previous images the deep survey has uncovered a bizarre variety
of shape and structure in distant galaxies, which only previously
appeared as fuzzy blobs from ground based telescopes.

credit:   Richard Griffiths, The Johns Hopkins University
     and NASA

*The distance to the largest galaxy in the image has been
measured by Prof. Rogier Windhorst and his group at Arizona State
University, using the Multi-Mirror Telescope in Arizona, operated
by the University of Arizona and the Smithsonian Institution.

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Mon, 08 Nov 1993 12:12:02 -0500 (EST)
% From: Mostly Harmless <[email protected]>
% Subject: HST Deep-Sky Survey Finds Interacting Galaxies in a Cluster

I don't know if this is covered in any of the follow-up replies, but I just
received the STS-61 press kit (it'll be ready in a couple of days), and the
burn list includes some reboost maneuvers (if propellant margins permit).

- dave

From:	US1RMC::"[email protected]" "MAIL-11 Daemon" 12-NOV-1993 
To:	[email protected]
CC:	
Subj:	JPL/Wide Field and Planetary Camera-II fact sheet

FACT SHEET:      WIDE-FIELD AND PLANETARY CAMERA-II

      When astronomers open their great mountaintop observatories
to the heavens, their powerful telescopes serve as time machines
to uncover events as they happened hundreds, thousands, millions
or billions of years in the past.  Peering back through space and
time on a clear, dark night, large telescopes can resolve distant
galaxies at the edge of the observable universe -- revealing them
as they would have appeared long ago, when the universe was much
younger than it is now.

      Even on the summits of remote mountains where the air is
clear and the night skies are free from the glare of city lights,
slight density variations in the overlying ocean of air cause
light rays to bend, resulting in the blurring of images that
often interferes with telescopic observations.  The great joy in
an astronomer's life is the rare night of good "seeing," when the
air is calm and the stars appear steady and sharp.  Even then,
absorption by the constituents of the atmosphere blocks radiation
from reaching the ground, except in narrow spectral windows at
visible and near infrared wavelengths.

      Visionary astronomers had long dreamed of operating
telescopes above the obscuring and turbulent layers of Earth's
atmosphere.  With the historic launch of NASA's Edwin P. Hubble
Space Telescope, carrying the Wide-Field and Planetary Camera
among its retinue of scientific instruments, astronomers of today
are seeing these dreams become a reality.

      Using the Hubble Space Telescope, astronomers are already
gaining new insights into the nature of galaxies -- the building
blocks of the universe -- and into the major constituents of our
own Milky Way galaxy, where stars and star-forming clouds of gas
and dust lie.  Newly observable Cepheid variable stars are
helping to measure cosmic distances with greater accuracy than
ever before.  Astronomers are able to see and measure uncharted
regions of the ultraviolet spectrum, where many quasar emissions
and telltale signatures of intergalactic hydrogen gas lie hidden
from ground-based observation.

      Closer to home, many of the remarkable features of our own
planetary system are visible in new detail.  For instance, the
gaseous giants Jupiter and Saturn and their corresponding
satellites, photographed at close range during the flybys of the
Voyager spacecraft in the 1970s and 1980s, are observable in fine
detail using the orbiting Hubble Space Telescope.


THE WIDE-FIELD AND PLANETARY CAMERA

      The first-generation Wide-Field and Planetary Camera (WFPC-
I), launched on April 24, 1990, is one of five scientific data-
gathering instruments onboard the Hubble Space Telescope (HST).
Designed and built by the California Institute of Technology's
Jet Propulsion Laboratory under contract to NASA, the camera
occupies the prime location at the center of the telescope's
focal plane and provides key imaging capability for both planetary 
and deep-sky objects, such as star clusters and galaxies.

      By the time WFPC-I was launched, a second-generation
replacement instrument, the Wide-Field and Planetary Camera-II
(WFPC-II) was in the early stages of construction.

      Two months after the launch, scientists detected a flaw --
an error of curvature termed spherical aberration -- in the
telescope's 2.4-meter-diameter (94.5-inch) primary mirror.
Subsequent studies of star images returned by the telescope
showed that the surface of the mirror was too flat by an amount
equal to about 1/50th the width of a human hair.  With the flaw,
only about 12 percent of the light is brought into focus within a
circle with a diameter of 0.2 arc second rather than the
originally specified 70 percent of the light.  (An arc second is
an angular measure equaling 1/3,600th of a degree.)

      As a result, light is spread out over a much larger area in
a fuzzy halo rather than being focused into a sharp, pointed
image.  For compact bright objects, computer image processing has
been successful in restoring to a considerable extent the
telescope's intended image sharpness or resolution.  However, for
diffuse objects, very faint compact objects and objects located
in crowded star fields, computer processing is not effective.
Consequently, these objects cannot be satisfactorily studied by WFPC-I.

      During the first Hubble Space Telescope servicing mission,
planned for December 1993 aboard the space shuttle Endeavour,
WFPC-I will be replaced by the recently completed second-
generation instrument, WFPC-II.

      The original purpose of WFPC-II was to provide a backup for
WFPC-I, which had been designed and built in the late 1970s and
early 1980s.  Several design changes had been made to enhance
WFPC-II's overall imaging capability.  They included the use of
newly available, low-noise charge-coupled device (CCD) light
detectors, an upgraded set of spectral filters and a flat-field
photometric calibration system.

      Because of the flaw in HST's primary mirror, the task to be
undertaken by WFPC-II grew to include the correction of the
blurred incoming light by means of modifications that could be
built into WFPC-II's relay optics.  To enable these modifications
to work correctly and reliably in orbit, WFPC-II was further
modified to include mechanisms to permit remote control alignment
of its corrective optical system relative to the telescope.  This
is achieved by means of an articulated pickoff mirror and three
articulated fold mirrors within the instrument.

      With these modifications, WFPC-II is expected to fully
restore the originally planned imaging capability of the HST
within a field of view covered by the three wide-field camera
channels and one planetary camera channel in WFPC-II.  The
ability to obtain crisp images from the near infrared to the far
ultraviolet promises to revitalize the HST science community,
whose diverse interests range from observations of nearby planets
to studies of the most distant objects in the observable universe.


THE HUBBLE SPACE TELESCOPE

      The Hubble Space Telescope was launched and deployed into
orbit 600 kilometers (330 nautical miles or 370 statute miles)
above Earth's surface from NASA's space shuttle Discovery on
April 24, 1990.  The telescope orbits Earth once every 95 minutes.

      For a planned 15 years until 2005, the telescope and its
imaging instruments, including WFPC-I and WFPC-II, will study
objects ranging from asteroids, comets and planets within our
solar system to galaxies and quasars at the farthest and oldest
reaches of the universe.

      In conjunction with the space telescope, WFPC-II provides
images which are sharper and more steady than any attainable from
Earth's surface at visible wavelengths, and provides access to
ultraviolet wavelengths which are completely inaccessible to
ground-based observatories.

      For distant galaxies, WFPC-II's sharp and steady images will
stand out more clearly from the background, allowing astronomers
to study detailed structures and populations of stars at much
greater distances than possible from the Earth.  Our knowledge of
such details will be extended by a factor of seven deeper in
space and farther back in time.

      The space telescope is 13.1 meters (43 feet) long and 4.3
meters (14 feet) in diameter and about the size of a railroad
tank car.  It weighs 12,000 kilograms (26,000 pounds), about as
much as eight automobiles.

      Light from distant space objects enters the telescope's tube
at one end and strikes the primary mirror 2.4 meters (94.5
inches) in diameter.  The light reflected by the mirror then
converges toward the secondary mirror, located 4.9 meters (16
feet) in front of the primary mirror.  The secondary mirror is
only 30 centimeters (12 inches) in diameter.  From there, the
beam of light narrows further and intensifies, passing through a
60-centimeter (24-inch) hole in the center of the primary mirror.

      The light is then measured by one of the science
instruments.  While four of the telescope's five instruments are
mounted directly behind and perpendicular to the focal plane,
WFPC-II is mounted radially in the telescope, and light from the
focal plane is deflected into the camera by a pickoff mirror.  In
all, the science instruments include:

      -- The Wide-Field and Planetary Camera, which provides
photometric imaging over a wide field of view from the far
ultraviolet to the near infrared;

      -- The Faint Object Camera, designed for higher spatial
resolution over a relatively small field of view, primarily in
the ultraviolet;

      -- The Faint Object Spectrograph, which examines the
ultraviolet and visible spectra of distant objects in order to
study their chemistry;

      -- The Goddard High Resolution Spectrograph, providing the
sharpest discrimination of spectra in the ultraviolet;

      -- The High Speed Photometer, which measures the brightness
of sources and rapid changes in their brightness over time.

      The science instruments generate data in digital form, which
are transmitted to the ground via NASA's Tracking and Data Relay
Satellite System (TDRSS).  The data are then converted into
pictures and other usable forms.

      Electrical power for the space telescope is provided by two
arrays of 48,000 solar cells positioned like a pair of wings on
either side of the telescope's main tube.  Power is stored in six
batteries so that operations are continuous, even when the
telescope is in Earth's shadow.

      The space telescope's pointing control system is responsible
for moving the telescope and pointing it at the celestial object
selected for study.  The system is made up of gyroscopes,
momentum wheels, magnetic torquers and star trackers, which can
keep the telescope pointed to within 7/1000ths (0.007) of an arc
second -- the equivalent of locking onto a dime in San Francisco
from Los Angeles (or in Washington, D.C., from Boston) more than
650 kilometers (400 miles) away.

      Other support systems include the space telescope's main
computer, which controls the overall spacecraft; high-gain
antennas, which receive ground commands and transmit data back to
Earth; a thermal control system using thermal blankets and a
network of tiny heaters to keep the telescope within an
acceptable temperature range; and a safing system, designed to
control the telescope to protect it from damage in the event of
serious computer problems or loss of communication with ground-
controllers.


HST PERFORMANCE REPORT AND NEW OPTICAL REQUIREMENTS

      The space telescope's optical system was designed to
concentrate 70 percent of the light in a star image inside a
circle 0.2 arc second in diameter.  The flaw in the telescope's
primary mirror caused a significant degradation in this
performance, allowing only 12 percent of the light to fall within
such a circle.

      The remainder of the light is spread over a larger region in
the focal plane, causing a blurred rather than sharply focused
image to arrive at all of the science instruments.  Images that
require a great deal of clarity and detail, such as binary stars
orbiting each other at close range, or star clusters containing
thousands of individual stars enveloped by dust or luminous gas,
suffer from the loss of spatial resolution.

      The second-generation Wide-Field and Planetary Camera had
been under construction for four years when the aberration in the
primary mirror was discovered.  In order to recover from the
space telescope's defect as quickly as possible, the schedule to
complete WFPC-II was accelerated, and a requirement was added
that the camera's internal optical system be redesigned to
compensate for HST's spherical aberration.

      This was accomplished by altering the mirrors in WFPC-II's
relay optics in such a way as to introduce exactly the opposite
spherical aberration into the relays.  The new shape in the optics 
would cancel the aberration of the telescope's primary mirror.

      The corrected imaging performance of the Hubble Space
Telescope would also require 10 times more precise alignment of
its optical components than was necessary with the first Wide-
Field and Planetary Camera.  Miniature images of HST's primary
mirror formed within WFPC-II would have to be centered to within
less than 0.1 millimeter (0.004 inch) on the dime-sized secondary
mirrors of the relay cameras.  If not, another aberration -- coma
-- would be introduced, quickly defeating the purpose of the
corrective optical design.

      To assure accurate alignment, WFPC-II includes four new
alignment mechanisms that can be controlled from the ground.  The
previously fixed pickoff mirror and three of four fixed "fold"
mirrors in WFPC-I were replaced in WFPC-II by articulated,
adjustable mirrors than can be tipped and tilted to assure that
the light beam from the telescope falls precisely on the centers
of the relay secondary mirrors after the instrument is launched
and installed in the orbiting HST.


WFPC-II SCIENCE OBJECTIVES

      During its lifetime, the Hubble Space Telescope will see
distant galaxies and quasars, the stars and stellar systems of
our Milky Way galaxy and the constituents of our own solar
system, including planets with their accompanying satellites,
asteroids and comets.  Perhaps HST will detect planetary systems
around other stars.

      While solar system studies by WFPC-II will uncover treasures
of new information, the real gold mine for celestial prospectors
is expected to lie in distant fields.

      The WFPC-II project exerted unprecedented efforts to
eliminate contamination to maximize the sensitivity of the
instrument to light in the far ultraviolet regions of the
spectrum.  WFPC-II is especially sensitive to wavelengths around
1216 angstroms, the wavelength of the strongest emission line
(Lyman-alpha) of atomic hydrogen.  Since ultraviolet imaging from
ground-based telescopes is prevented by atmospheric absorption,
WFPC-II will be uniquely capable of observing in this
scientifically fascinating region.

      Astronomers have set for themselves three major tasks in the
field of cosmology, the study of the origin and evolution of the
universe:  to refine and extend the scale of cosmic distances; to
understand how galaxies evolved from the earliest times to the
present; and to test fundamental theories of the expanding universe.

      Astronomical distances are measured by a variety of
carefully devised methods, all of which depend upon a knowledge
of the distance from Earth to the sun.  Distances to the nearest
stars are established by direct triangulation as Earth moves in
its orbit around the sun.  These stars are then used to calibrate
still greater distances from brightness measurements of stars in
clusters.

      The great achievement enabling astronomers to measure the
distances between galaxies was the discovery by Henrietta Leavett
early in this century that certain highly luminous variable stars
-- Cepheids -- have a definite relation between the period of
their light variation and their absolute luminosity.  Thus, the
apparent brightness of Cepheids detected in a relatively nearby
galaxy can be used to estimate the distance to that galaxy.

      The most distant galaxies are much too far away to allow
individual stars -- even Cepheids -- to be seen.  Their distances
can only be estimated in terms of the general expansion of the
universe; the velocity of recession (or red shift of spectral
lines) increases with increasing distance.

      But in that method lies a seed of doubt:  We reside in an
immense cluster of galaxies, whose mutual gravitational
attraction may alter their motions, or the apparent universal
expansion inferred from them.  Extrapolated to yet larger samples
of the universe, small effects from this cause could build up to
significant error.

      How do astronomers hope to surmount this problem?  The
straightforward answer is to obtain even better, more precise
measurements.  WFPC-II will be able to measure stars in distant
galaxies 100 times fainter than the 5-meter (200-inch) Hale
Telescope atop Palomar Mountain near San Diego, Calif.  The
capability will enable astronomers to detect and measure Cepheid
variables in galaxies that, until now, have been too distant to
calibrate.  By so doing, measurements of the distances to local
galaxies will, for the first time, be tied to the scale of
distances to great clusters of galaxies outside the local group.

      The WFPC-II supports many other investigations across a
diverse range of astronomical topics.  Objectives established by
the WFPC-II science team are:

      -- To calibrate the cosmic distance scale to within an error
of not more than 10 percent;

      -- To investigate the evolution of distant and local galaxies;

      -- To study populations of stars in distant galaxies and
crowded fields;

      -- To examine the detailed structure and surroundings of
distant sources such as quasars;

      -- To observe cloud motions and identify compositions of
planetary atmospheres in our solar system.


THE SECOND-GENERATION WIDE-FIELD AND PLANETARY CAMERA (WFPC-II)

      The WFPC-II instrument comprises four camera systems:  three
wide-field cameras having one magnification, and one planetary
camera having a magnification of about 2.2 times greater.

      The wide-field cameras provide the greatest sensitivity for
the discovery of faint objects.  They have a focal ratio of
f/12.9, a field of view of 2.67 arc minutes on a side, and a
resolution of 0.1 arc second per picture element, or pixel.  (An
arc minute is an angular measure equaling 1/60th of a degree.)

      The planetary camera facilitates high-resolution studies of
individual objects such as planets, galaxies and stellar systems.
This camera has a focal ratio of f/28.3, a field of view of 34.2
arc seconds (0.57 arc minutes) on a side, and a resolution of
0.046 arc second per pixel.  This resolution would allow the
camera to resolve a baseball-sized object from a distance of
about 400 kilometers (250 miles).

      When light comes to a focus within the camera, it is
transformed into electrical signals by solid-state imaging
sensors, called charge-coupled devices (CCDs).  All four WFPC-II
camera systems are equipped with new, highly improved CCD
detector arrays, each containing 640,000 pixels arranged in 800
rows and 800 columns.  Transmitted back to Earth and recombined
as a mosaic, the image produced by the four CCDs contains 2.56
million pixels.

      The cameras are sensitive to light at wavelengths ranging
from ultraviolet to the near infrared (1,200 to 10,000
angstroms).  Forty-eight different color filters mounted on 12
filter wheels can be deployed selectively in front of the
cameras.  The filter set includes wide-band ultraviolet filters
that transmit light only shortward of 2,000 angstroms.  Exposure
times are controlled by an electrically operated shutter.
Shutter speeds can be varied from 110 milliseconds (about 1/10th
second) to 28 hours.

      On Earth the WFPC-II instrument weighs 281 kilograms (619
pounds).  In orbit, it consumes an average of 200 watts of
electrical power.  A system consisting of a radiator, heat pipes
and thermoelectric coolers keeps the CCDs at selected constant
temperatures of between -22 degrees and -90 degrees Celsius (-8
and -130 degrees Fahrenheit).  The cold operating temperatures
are needed to keep the background signal in the CCDs at a minimum.


THE HUBBLE SPACE TELESCOPE SERVICING MISSION

      STS-61 is the first of a series of planned Hubble Space
Telescope servicing missions.  It is tentatively scheduled for
launch at 4:57 a.m. Eastern Standard Time on Dec. 1, 1993.  The
mission was originally designed to replace major components of
the space telescope and its science instruments as improved
technologies became available.  Because of several problems that
have occurred since the telescope was launched, the first mission
will be largely one of repair and maintenance.

      The principal goals of STS-61 are to correct for the primary
mirror's spherical aberration by removing WFPC-I and installing
WFPC-II, and removing the High Speed Photometer and installing in
its place the Corrective Optics Space Telescope Axial Replacement
(COSTAR), which will focus light entering the remaining three
axial instruments.

      Also planned for STS-61 is replacement of the telescope's
solar arrays to stabilize the vibration that occurs each time the
telescope crosses from daylight into the cold darkness of Earth's
shadow.  The STS-61 astronauts will also replace several
gyroscope units and computers, and make repairs to the High
Resolution Spectrometer.


ORGANIZATIONS AND PERSONNEL

      Larry Simmons at the Jet Propulsion Laboratory is the WFPC-
II program manager.  Dr. John Trauger at JPL is the WFPC-II
principal investigator.

      Overall management of the Hubble Space Telescope project is
the responsibility of NASA's Goddard Space Flight Center in
Greenbelt, Md.  NASA's Marshall Space Flight Center in
Huntsville, Ala., was responsible for telescope development and
launch.  The Space Telescope Science Institute at Johns Hopkins
University in Baltimore, Md., is operated by Associated
Universities for Research in Astronomy Inc. under contract to
NASA's Goddard Space Flight Center.

      The optical telescope assembly of HST was fabricated by the
Perkin-Elmer Corporation (now Hughes Danbury Optical Systems
Inc.) in Danbury, Conn.  The telescope was integrated by Lockheed
Missiles and Space Corporation in Sunnyvale, Calif.

      The European Space Agency provided the space telescope's
solar arrays and the Faint Object Camera.  Other instrument
sources are: the Faint Object Spectrograph, built by Martin
Marietta Astronautics for the University of California at San
Diego; the High Resolution Spectrograph, built by Ball Aerospace
Corp., Boulder, Colo., for Goddard Space Flight Center; and the
High Speed Photometer, built by the University of Wisconson at
Madison, which will be replaced by COSTAR.

      WFPC-II was designed and built by the California Institute
of Technology's Jet Propulsion Laboratory for NASA's Office of
Space Science, Washington, D.C.

                           #####

11-2-93 DEA

Article: 78282
From: [email protected] (Ad absurdum per aspera)
Newsgroups: sci.research,sci.space
Subject: FYI #154 (Hubble in the House)
Date: 24 Nov 1993 01:06:13 GMT
Organization: Relayed, not written, by Lawrence Berkeley Laboratory
 
[Written by the American Institute of Physics and posted by us.  
Respond to <[email protected]> or other references below.  Always 
posted here on sci.research; sometimes crossposted to other 
interested groups with followups directed here. Back issues, 
along with PHYSICS NEWS UPDATE and the American Physical Society 
column WHAT'S NEW, are archived on NIC.HEP.NET for your anonymous 
FTP'ing pleasure, courtesy of H.A. Kippenhan, Jr. Enjoy! -jc]
 
Science Committee Hearing on Hubble Space Telescope Repair Mission
 
FYI No. 154, November 23, 1993
 
Indicative of the great interest there is in the early December
shuttle flight to repair the Hubble Space Telescope (HST) was a
November 16 hearing of the House Subcommittee on Space.  As one of
NASA's planned great observatories, HST is seen, in the words of
subcommittee chairman Ralph M. Hall (D-Texas), as "a project that
became a symbol of a troubled space program." It is clear from the
hearing that the upcoming mission has the potential to renew
congressional optimism about NASA, with the reverse being equally true.
 
On October 4, NASA agreed to a $25 million settlement with The
Perkin-Elmer Corporation and Hughes Danbury Optical Systems, Inc.
"by reason of the defect in the primary mirror."  An additional
$6.5 million in future HST-related contracts will be performed by
Hughes Danbury at no cost through the end of 1999.  The agreement
specifies that it is not to be construed as an admission of any
liability on the part of Perkin-Elmer and Hughes Danbury.  NASA's
General Counsel testified that "actual, monetary damages ...from
the defect in the mirror" was $87 million, which he felt could not
be recovered because of "certain legal defenses."  Hall and Ranking
Republican James Sensenbrenner (R-Wisconsin) were generally
supportive of the agreement, although Rep. Dana Rohrabacher
(R-California) criticized the lack of any personnel action being
taken against responsible individuals.
 
First to testify was Lieutenant General Thomas P. Stafford,
Chairman of the Hubble Space Telescope Servicing Mission Review
Team.  His team of nine other individuals first met in September
1992.  Their primary charge was to review NASA's plans for
conducting the servicing of the telescope.  They made a series of
recommendations, the chief among them being one calling for the
appointment of a mission director with overall responsibility for
the mission.  Other technical recommendations including the testing
of tolerances, training, and that "as much testing and verification
as possible should be planned for the Hubble Space Telescope while
the Shuttle is still on-orbit."  Additional recommendations
concerned management and review procedures, and the provision of
some backup crew members for the mission.
 
Also testifying was Bill Colvin, NASA's Inspector General. Colvin
explained, with the aid of large visual displays, "six significant
irregular events which occurred during the manufacture of the
mirror."  His team's investigation revealed, in his words, that
"obvious evidence of errors existed at all stages of the
manufacturing process of the primary mirror.  Yet it appears no
serious attempt was made to resolve the source of these errors."
Colvin testified that one Perkin-Elmer engineer was "haunted" by
the interferometric pattern of the refractive null corrector test
of the primary HST mirror.  Colvin continued, "to our best
determination, Perkin-Elmer did not share the discrepant results of
the vertex radius test with NASA."  These findings formed the basis
of the civil complaint filed by the Department of Justice against
Perkin-Elmer, which led to the October settlement agreement.
 
In the conclusion of his testimony, Stafford sounded a note of
caution about the future of the Hubble Space Telescope and its
repair mission: "Throughout our review the Team was very concerned
about relaying overly optimistic expectations to the public....
Every press release should convey the ambitious and difficult
nature of this mission and the new challenges involved.  NASA again
faces a challenge in conveying to the public that even if all of
this mission's objectives cannot be accomplished, meaningful
science will still be achieved at factors far greater than
available on Earth."
 
The twelve-day mission to repair the telescope is scheduled to
lift-off at 3:00 am on December 1.
 
UPDATE ON THE PENNY-KASICH BUDGET LEGISLATION: Last night, the
House rejected by a vote of 219-213 this amendment which contained
provisions establishing a Department of Science, reduced fusion
energy funding, and capped university research overhead costs (see
FYI #153.)
 
###############
Public Information Division
American Institute of Physics
Contact: Richard M. Jones
(301) 209-3095
###############
 
Joe

"Just another personal opinion from the People's Republic of Berkeley"

Disclaimer: Even if my employer had a position on the subject,
I probably wouldn't be the one stating it on their behalf.

Article: 2050
From: [email protected] (UPI)
Newsgroups: clari.tw.space,clari.news.gov.agency,clari.tw.aerospace
Subject: Hubble Space Telescope facts and figures
Date: Mon, 29 Nov 93 22:18:40 PST
 
	CAPE CANAVERAL, Fla. (UPI) -- The Hubble Space Telescope is
the most powerful optical instrument ever built for operation above
Earth's obscuring atmosphere. Here are telescope details at a glance: 

	-Cost: $1.55 billion for the telescope hardware; $400 million
for development of ground systems; $200 million for development and
planning for in-orbit servicing; $160 million (per year) for operations 
at the Space Telescope Science Institute at Johns Hopkins University in 
Baltimore and $40 million per year for grants and data storage. 

	-Primary contractor: Lockheed Missiles and Space Co., Sunnyvale,
Calif.

	-Mirror contractor: Hughes-Danbury Optical Corp., formerly Perkin-
Elmer Corp. of Danbury, Conn.

	-Launched: April 25, 1990.
	-Planned lifetime: 15 years.
	-Orbital altitude: 380 miles.
	-Length: 43.5 feet.
	-Weight: 25,500 pounds.
	-Diameter: 14 feet.

	-Telescope design: Cassegrain; light enters the telescope
tube, bounces off a primary mirror and back up to a smaller, secondary
mirror mounted near the opening of the tube. From there, the light
bounces back down through a hole in the primary mirror and is brought
to a focus at the ``focal plane'' where cameras and other instruments
can be placed to record the concentrated light. 

	-Primary mirror: a 1,827-pound, 94.5-inch mirror made of ultra
low- expansion titanium silicate glass coated with aluminum and
magnesium fluoride to enhance reflectivity. The special coating is
just 4 millionths of an inch thick. After the telescope's April 25,
1990, launch, NASA managers discovered that the primary mirror
suffered from spherical aberration. 

	-Secondary mirror: a 27.4-pound, 12.2-inch mirror.
	-Mirror support truss: graphite epoxy.
	-Distance between primary and secondary mirror: 16 feet.
	-Primary mirror hole: 24 inches wide.
	-Focal plane: 4.9 feet behind front surface of primary mirror.
	-Focal ratio: F/24.
	-Solar panels: two 7.8-foot wide, 39.4-foot long panels.
	-Solar cells: 48,000 (24,000 per panel).
	-Electrical power: 2,400 watts, minimum.

	-Data transmission rate: 1 million bits per second; at this
rate, the contents of a 30-volume encyclopedia could be transmitted in
42 minutes. 

	-Aiming accuracy: 0.007 arc seconds, equivalent to keeping a
beam of light 600 miles long centered on a target 1.2 inches wide. 

	-Scientific instruments: five, all of which can be replaced or
repaired in orbit by spacewalking astronauts. 

	-Instrument power consumption: 110 to 150 watts.

	The Hubble Space Telescope is equipped with two cameras, a
wide-field planetary camera capable of studying large areas of space
and taking Voyager-class photos of the planets, and a faint object camera 
that will be used to study powerful quasars and other distant objects. 

	It also is equipped with two light-splitting spectrographs,
one to study the spectra of faint objects in ultraviolet light and one
for high-detail research involving exploding galaxies, quasars and
other dense objects. The telescope also is equipped with a high-speed
photometer, a sort of high-tech light meter, to study the total light
given off by a target. 

	Finally, one of the telescope's three guidance sensors can be
used to measure stellar positions with unprecedented accuracy. 

RE: Note 612.361

>From: [email protected] (UPI)
>
>	The Hubble Space Telescope is equipped with two cameras, a
>wide-field planetary camera capable of studying large areas of space
>and taking Voyager-class photos of the planets...

This is the first I've heard of Hubble's planetary imaging capabilities as
comparable to Voyager images. Assuming the claim is referring to Voyager images
taken around the time of a close encounter, I find this hard to believe. The
few planetary images I've seen published that were taken by Hubble are good
but NOWHERE near Voyager images. Anyone else know more?
						-- Tom

    I'm not sure if every cable company subscribes/offers this, but 
    Nashoba Cable now offers a NASA channel which normally offers 
    coverage and space shows/information every day from 6 AM until 8 PM
    (at which time the channel converts to Playboy, or a blank screen if
    you don't subscribe to that).  And now with all the Hubble activity,
    Nashoba Cable has switched the NASA channel to another channel 
    between the hours of 8 PM and 6 AM.  So there is now 24 hour coverage
    of this mission available.  Get to see some great shots of the 
    astronauts in action, and listen in to them working on the repairs.
    
    dave
    

Mission Control Center
STS-61 Status Report #9
Monday, December 6, 1993, 8 a.m. CST

Spacewalking STS-61 astronauts Tom Akers and Kathy Thornton, working in 
the Space Shuttle Endeavour's payload bay, successfully jettisoned a bent 
solar array and installed two new solar arrays on the Hubble Space 
Telescope during a six hour and 36 minute spacewalk that ended at 4:05 
a.m. CST Monday. 

During a Monday morning press briefing, HST managers applauded the crew's 
performance. 

"I believe that the first objective has been met," said Joe Rothenberg, 
HST flight project director. "We can handle on-orbit servicing and we can 
handle contingencies." 

The early Monday spacewalk marked the second extravehicular activity in 
as many days during the HST servicing mission. Crew members are expected 
to perform three more spacewalks during this mission. 

Akers and Thornton spent the duration of their spacewalk working with the 
telescope's solar arrays which provide power to the four-story tall 
orbiting observatory. The spacewalking duo began their work in the 
payload bay at about 9:29 p.m. CST Sunday. At about 10:51 p.m. CST, 
Thornton, who was positioned at the end of Endeavour's robot arm 
alongside one of the arrays, attached a transfer handlebar to the right 
solar array which failed to completely retract on Sunday because of a 
kink in its bi-stem framework. Akers then disconnected the array at the 
telescope body and its electrical connections were broken before Thornton 
released the array above the payload bay. 

After  Mission Specialist Claude Nicollier, the robot arm operator from 
the shuttle's flight deck, moved Thornton back down into the cargo bay, 
Commander Dick Covey and Pilot Ken Bowersox maneuvered the shuttle away 
from the drifing array. The astronauts and ground observers got a long 
last view of the kinked solar panel and observed its solar blankets 
flutter as they felt the shuttle's gentle firing pulses. 

"It looks like a bird," Thornton told ground flight controllers as the 
array drifted away from the shuttle. 

Scientists have estimated it will take the discarded solar array about 
one year to re-enter the Earth's atmosphere where it will burn up. 

At about 11:17 p.m. CST, Thornton used the transfer handle once again to 
lift one of the new solar arrays from the solar array carrier in 
Endeavour's payload bay and into position on the telescope where it was 
installed. Thornton and Akers then manually folded down the other old 
solar array which had been automatically rolled up Sunday, and at about 2 
a.m. CST Akers tied the old array into position in the solar array 
carrier. The old solar array will be returned to Earth for study. 

Just before 3 a.m. CST Monday, the spacewalking astronauts completed the 
installation of the second solar array and a few minutes later 
controllers at the Space Telescope Operations Control Center in 
Greenbelt, Maryland, confirmed that both of the new solar arrays were 
electrically alive and well. The new solar arrays will be unfurled after 
the fifth spacewalk is completed early Thursday. 

At about 4:05 a.m. CST as the spacewalking astronauts were wrapping up 
their payload bay activities, CAPCOM Greg Harbaugh congratulated Akers 
who had just broken the record for longest EVA time in the shuttle era by 
logging in 22 hours and 50 minutes, surpassing fellow astronaut Jerry 
Ross' record by one minute. 

"Thanks, but I'm afraid it'll be short lived," Akers said, referring to 
his new record entry. At the end of the EVA as the two spacewalkers had 
re-entered the airlock, Thornton reported ear problems. As a result, the 
airlock was depressurized and then repressurized at a slower rate until 
the airlock's pressure reached the 10.2 pounds per square inch 
requirement. 

Crew members' sleep period begins at 9:57 a.m. CST and they will wake up 
at 5:57 p.m. CST today to begin their sixth flight day activities. The 
mission's third spacewalk will highlight the sixth flight day. EVA 
astronauts Story Musgrave and Jeff Hoffman, who performed this mission's 
first EVA, once again will step into the payload bay where they will 
changeout the telescope's wide field/planetary camera. 

All of Endeavour's systems continue to perform well as the shuttle 
circles the Earth every 95 minutes in a 320 by 313 nautical mile orbit. 

[This person appears to have a good conduit of information from inside 
 HST operations  -dg]


From: [email protected] (HST Newsgroup)
Newsgroups: sci.astro.hubble
Subject: HST now has two new Solar Arrays !!
Date: 6 Dec 1993 18:17:25 GMT
Organization: College of Liberal Arts and Sciences, ASU

			SM Report #5

	6:00 AM December 06	340:11:00

	Summary of recent activities:

	EVA #2 has been completed successfully.  HST now
has two brand new Solar Arrays.  

	The EVA crew, Kathy Thornton and Tom Akers, 
started the EVA a bit early, leaving the airlock at
about 10:30 pm eastern time.  The first task was to 
jettison the + solar array, the one which had the 
kinked bi-stem.  This was accomplished by Kathy
Thornton, riding on the RMS arm, simply releasing
the array, backing away the arm, then backing away
Endeavour.  I missed the TV image of the array jettison
but am told that it appeared to "flap away" as the
Endeavour backed away.  It has been tracked on radar
and is well separated (more than 20 miles) from the 
Endeavour.  The EVA crew then installed the new + Wing
with no incidents.  They removed the old - Wing and stored
it on the Solar Array carrier in the orbiter bay for
return to earth.  They then installed the new - Wing
on the HST.  The STOCC at GSFC ran electrical aliveness
tests which were successful.  The arrays will remain
stowed until later in the mission.

	The EVA crew finished their assigned tasks a
little early and did some preparatory work for tommorrows
EVA.  This should give tommorrows EVA crew a head start
on their activities.  

	During the day yesterday their were several SI
reconfigurations which demonstrated that the fuse plugs
installed on EVA #1 are all working properly.

	The SIs are being maintained in a warm state in
preparation for later activities.  They seem to be 
staying warmer than the thermal models indicated, so several
steps have been taken to keep them from getting too warm.
The GHRS is being kept warm with 3 DEBs on instead of 4. 
We have had to do a little balancing act with the WFPC. The
sun has frequently been directly on the radiator.  In this
condition the TECs can barely keep the CCDs cold without
violating internal limits.  At one point we had to shut
the TECs off for a few hours.  Now that the Solar Array
installation has been completed HST is being rotated to
an orientation which should keep the radiator shadowed
enough for temperatures to remain within limits.

	Problems/Issues/Changes under consideration:

	The GHRS pressure sensor has detected several "pulses"
of pressure over the last two days.  The first occurred during
the first EVA while Story Musgrave was in the aft shroud changing
out the RSU assemblies.  This was believed to be due to water
from the suit cooling system and should not cause any problems.
The second was during EVA #2 when the Endeavour fired jets and 
backed away from the jettisoned solar array.  The pressure jumped 
up for about three minutes and then dropped back down again.  This
has raised some contamination concerns, which are being looked
into by engineers and contamination experts at GSFC and JSC.
The FOS ion gauge has been turned on to provide additional
monitoring of aft shroud internal pressures.

	Near-term plans:

	EVA #3 is scheduled for tommorrow.  This EVA will replace
the WFPC-I with the WFPC-II and will install two replacement 
magnetometers.

WFPC replacement appears to have gone as planned.

I watched them removing WFPC-I on CSPAN.   Really neat stuff!  It is quite
amazing that Tom could handle that 600 lb camera so nimbly, even if he does not
have to contend with gravity.

Yeaaaa!  3 down, 2 to go.  Costar tonight, I think.

Burns

COSTAR is tonight...  It was Jeff on the arm (or "crane" as CSPAN called it)
and Story was the free-floater (man can he zip around the place).


K.T. and Tom are the EVA crew tonight for COSTAR and some other miscellaneous
(low-priority) upgrades.

- dave

           STATUS REPORT:  HST First Servicing Mission 
           
             As of Mission Elapsed Time:  Day 8, 11:00
                        (15:28 EST 12/10/93)
                               
                    K. Carpenter and M. Niedner                   
                    HST Project Science Office
                           NASA - GSFC 
                           
SI Status:
  
    WFPC2 is in hold, with heatpipe heaters on to prevent condensation of
      of contaminants (decontamination mode), windows at 22 deg C
    COSTAR is in Servicing Mission hold mode (normal hold, except arm 
      heaters off)
    GHRS is in hold mode, side 2 low-voltage on  
    FOC is in hold mode, side A
    FOS has low-voltage & ion (pressure) gauge on
    FGS's are in default position under SSM (telescope) control

    WFPC2 has passed its functional test
    COSTAR has passed its functional test
    GHRS has passed its aliveness test, after installation of the RK.

Other notes:

    Spacecraft is in software sunpoint (as planned)    
    NSSCI (NASA Standard Spacecraft Computer) is in normal mode
    The new MSS's (magnetometers) are reported to be "fine"
     
Current Activities:

    FHST (Fixed Head Star Tracker) mapping to support low and high
      mode gyro calibrations

    Spacecraft is currently controlled by Real-time commands from the
      the Space Telescope Operations Control Facility (STOCC), prior to
      the initialization of SMS loads. 

Upcoming Events:

    Health and Safety load (SMS's begin) about 4 pm EST 12/11/93
      allows use and management of High Gain Antennas (HGA's) and
      positions HST to attitude at which first SMOV SMS will intercept
      timeline.

    SMOV (Servicing Mission Observatory Verification) begins on Monday
      12/13/93 at 16:00 EST.

And, finally, because it still looks so very impressive, here is one
final listing of the 

              Accomplishments and Major Events of the FSM:  
              --------------------------------------------

           launch, rendezvous and grapple of HST
           restoration of full gyro redundancy by replacement of RSU's 2 & 3 
             and ECU's 3 and 1 (We now have 6 fully functional gyros).  
           Replacement of 8 fuse plugs.  
           Solar array preparations for EVA 2.
           jettisoning of +V2 wing of Solar Array - I
           installation of both wings of Solar Array - II
           replacement of WF/PC I with WFPC 2
           new magnetometers (MSS1 and MSS2) piggybacked onto
             original magnetometers and tied in electonically to
             replace function of originals.
           replacement of HSP with COSTAR 
           installation of Coprocessor 
           recovery of MLI (multi-layer insulation) from RSIPE, to
              cover old magnetometers (on EVA #5)
           suspected coprocessor problem analyzed and found to be
             due to problem in communication links, not in flight hardware
           single-burn reboost of HST to 321 x 320 nm orbit 
           changeout of SADE-1
           SADE-1 aliveness test executed and passed!
           covering of original MSS's (magnetometers) 
             with multi-layer insulation
           installation of GHRS redundancy kit
           GHRS aliveness test executed and passed!
           deployment of new solar arrays
           deployment of high-gain antennas
           telemetry from Data Interface Unit 2 side A garbled,
             problem diagnosed as partial failure of side A flight hardware,
             decision made to switch to redundant side B (fully functional)
           grapple of HST with RMS arm
           deployment of HST

From:	US1RMC::"ASTRO%[email protected]" "Astronomy Discussion 
        List" 14-DEC-1993 01:22:02.06
To:	Multiple recipients of list ASTRO <ASTRO%[email protected]>
CC:	
Subj:	Re: Hubble fix

----------------------------Original message----------------------------
First, an introduction.  I'm Bill Gawne, a staff astronomer at the STScI
in Baltimore.  I work in HST science planning and scheduling.  This is
my first contribution to the ASTRO mailing list.

Peter Plantec asked:

>A: (how did) the mirror get so badly done on a multibillion dollar deal

The mirror was very well done.  It is probably the most perfectly wrong
mirror ever made.  The thing that has made the beautiful HST images you've
been seeing for the last several years possible is that the spherical
aberration is almost perfectly symmetric.

The specific cause of the aberration is that the mirror figure was
tested with a reflective null corrector in the Perkin-Elmer optics
lab while the final figure of the Ritchey-Chretin design was being
ground and polished.  After mirror finishing was complete, the figure
was checked with a refractive null corrector, which showed the classical
indications of spherical aberration.  According to Lew Allen's report
on the investigation into the HST optical problems, P-E optical
engineers decided to ignore the refractive null corrector test because
the reflective null corrector was considered to be better (it was
undoubtedly more expensive.)  The investigating team was given access
to the optics lab where the HST mirror had been final figured, and found
the reflective null corrector still set up as it had been for the HST
work.  Careful analysis showed the null corrector had been slightly
mis-assembled, resulting in the reflection of the laser beam occuring
3 mm too far forward.  See Lew Allen's report for all the gory details.
I can get the specific title and ISBN for anybody interested.

>B: Why did we accept it?

Who are we?  Do you mean, "Why did NASA management accept a mirror that
has since proven to be misfigured?"  The answer to that is that NASA
management was prevented by DoD from placing any engineers in Perkin-
Elmer's labs since P-E was also making mirrors for the KH-11 and KH-12
spy satellites.  NASA was required by congressional direction to accept
P-E's engineering judgement without question.  See Smith's book, The
Space Telescope, for a good in-depth criticism of the problems with
Perkin-Elmer.  Smith's book is also quite critical of NASA management
practices, and well worthh reading by anybody interested in the details
of the HST project or _any_ "big science."

>C: Who does the person or persons who knew about it and set the damn
>thing up anyway, live with themselves.  Sombody HAD to know and kept
>thier chicken mouth shut.

The senior optical engineer for the project at Perkin-Elmer was reported
to have suffered a nervous breakdown after the mirror was delivered.
Draw whatever conclusions you wish.

Somebody else replying to these questions mentioned a "Challenger type
investigation."  Lew Allen's investigation was very similar to the Rogers
commission investigation into Challenger.  The findings are available for
all to read (admittedly they're written in the dreary "IRS Style Manual"
style so common in govt documents.)  Smith's book that I mentioned above
is a fine, critical look at the project which was published before launch.
Another excellent source of information is "A Strategy For Recovery," the
results of an investigation conducted by the HST Users Group into the
best way to get things back to spec.  It's this document that really drove
the choice to build COSTAR and modify WFPC-II to include articulating
fold mirrors.

-Bill Gawne
 HST Science Planning and Scheduling
 "We didn't build it, we just make it work."
 I am NOT an official spokesman for the STScI or anybody else

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date:         Tue, 14 Dec 1993 01:13:12 EST
% Sender: Astronomy Discussion List <ASTRO%[email protected]>
% From: Bill Gawne <[email protected]>
% Subject:      Re: Hubble fix
% To: Multiple recipients of list ASTRO <ASTRO%[email protected]>

                 HST Servicing Mission Observatory Verification

                                 NASA Facts

                 National Aeronautics and Space Administration

              Goddard Space Flight Center Greenbelt, Maryland 20771 AC

                              NF-194 June 1993



The question often is asked if NASA will be able to verify the optical
correction being made to the Hubble Space Telescope (HST) during the first
servicing mission while the telescope is still attached to the space shuttle,
or immediately after it is released from the shuttle?  The answer to both
questions is "No." A very detailed process, taking as long as 13 weeks for some
instruments, will be required before astronomers will know if the "fix" is
working as planned.  About seven weeks will be required after release to
complete the focussing and alignment procedures for the optically-corrected
Wide Field/Planetary Camera ll (WF/PC ll) and about ten weeks after release to
focus and align the train of corrected optics in the Corrective Optics Space
Telescope Axial Replacement (COSTAR)for the Faint Object Camera (FOC).  Only
when those focus and alignment procedures are completed will the HST be able to
produce camera images of demonstration quality.  Alignment of the COSTAR
corrective optics devoted to the Faint Object Spectrograph (FOS) and to the
Goddard High Resolution Spectrograph (GHRS) will be completed from nine to 13
weeks after release, according to project officials at NASA's Goddard Space
Flight Center, Greenbelt, MD.

Why Does Focussing And Alignment Take So Long?

The initial focus and alignment of HST's telescope, the Optical Telescope
Assembly (OTA), and the scientific instruments (Sl's) were accom plished
primarily during assembly of the HST prior to its launch in April 1990.  First
generation instruments on HST did not contain mechanisms which would allow them
to be aligned optically in orbit because the alignment tolerances inherent in
the original system design were relatively large.  After launch, most focussing
and alignment activity centered on adjusting the orientation of the OTA's
secondary mirror, and the lack of convergence of this procedure led to the
first discovery of HSTs spherical aberration.

With spherical aberration, the alignment process now becomes critical and
alignment tolerances are tight.  Both the WF/PC ll and COSTAR contain mecha
nisms that can tilt and translate some of their mirrors, allowing the incoming
beam of light from the telescope to be oriented precisely and focussed onto the
corrective optical surfaces (mirrors).  To achieve this precise alignment is a
time consuming process that involves the collection and analysis of sequences
of purposely out-of-focus images, the calculation of trial solutions for the
best positions of the mirrors and the repetition of the procedure to refine
these solutions.  Thus, the "first light" images taken with the WF/PC ll and
with COSTAR/FOC necessarily will be very "fuzzy."

The alignment of the corrective optics must be very precise.  To correct for
the incorrect shape of the telescope's primary mirror, astronomers must focus
and align precisely an image from this 7.8- foot (2.4 meter) mirror onto
corrective surfaces in the WF/PC ll and COSTAR which range in diameter from 12
to 25 mm, or from about the size of a dime to the size of a quarter.  The shape
of the corrective surface must be complementary to that of the OTA primary
mirror.  For example, the OTA primary mirror is too flat, so the corrective
surface on which its image is projected must be correspondingly steep.  This
allows all the light rays reflected off the primary mirror to travel the same
distance to the focal point.  With the current spherical aberration, light rays
reflected from different parts of the primary mirror come to focus at different
places.

Many other activities besides the alignment and focussing will take place
during the approximately 15-week orbital verification period.  These include
reactivation and engineering checkout of the major spacecraft subsystems and
verification of the performance of the new spacecraft components inserted
during the servicing mission-- solar arrays, gyros, computer co-processor among
others.  The project intends to carry out a small number of imaging
observations of astronomical sources after the completion of the WF/PC ll and
COSTAR focussing and alignment to demonstrate some of the scientific benefits
of the optical corrections, and these "Early Release Observations" will be made
public shortly after they are obtained.

Baseline observations with the instruments to be corrected by COSTAR, taken
before COSTAR deployment, will be made to verify that the shuttle servicing
activity did not perturb these instruments' optical alignment.  This is done by
comparing those results to pre-servicing data.  If COSTAR were deployed first,
there would be no way to determine definitively the source of any misalignment
problems.

The following is a preliminary summary of science related activities during the
orbital verification period.  Times are given in weeks after release from the
orbiter.  These times might change somewhat as further planning take place
regarding the orbital verification program.  Time intervals in weeks are to be
read as from the end of a week to the end of the other week.  For example, 1 -
3 would indicate from the end of week one through the end of week three.

Weeks Activity


O-2 Establish spacecraft health and safety and pointing control; checkout
        instruments.
1-2 Preparation for optical alignment: baseline observations; focus and align
        telescope; deploy COSTAR optical bench.

Wide FieldlPlanetary Camera ll

1-3 Coarse alignment.
3-4 Cool detectors.
4-7 Fine alignment.
7-8 First corrected stellar image.
7-13 Calibration.
9-13 Early release of astronomical image.
13 plus Science.

Goddard High Resolution Spectrograph

1 - 8 Science continues.
8 -10 Deploy COSTAR arm.
10-11 Coarse alignment.
11-13 Finealignment.
13-15 Calibration.
15 plus Science

Faint Object Camera

1-3 Deploy COSTAR arm.
3-5 Coarse alignment.
5-10 Fine alignment.
10 -11 First corrected stellar image.
10-12 Calibration
13-15 Early release of astronomical image.
12 plus Science.

Faint Object Spectrograph

1-2 Deploy COSTAR amm.
5-7 Coarse alignment.
7-9 Fine alignment.
9-12 Calibration.
12 plus Science.


The observatory will remain scientifically productive during this period.  The
Space Telescope Science Institute, Baltimore, Md. automatically will schedule
science activities during times when there are no checkout activities.  Early
on, before COSTAR is deployed, science data will be taken that are spheri cally
aberrated (as they have been during the past three years).  As soon as the
mirrors are aligned for a given instrument, that instrument will be used to
obtain science data while COSTAR is aligned for the next instrument.

The Hubble Space Telescope project is managed by the Goddard Space Flight
Center for the Office of Space Science, NASA Headquarters. The Space Telescope
Science Institute is operated by the Association of Universites for Research in
Astronomy (AURA) under contract to Goddard.

HST Daily Report #1028
December 10, 1993

The HST has been released from the orbiter and is a free flying satellite
once again.  Release occurred about 5:26 am EST today following the
grapple, disconnect, and unberthing operations.  All the orbiter related
servicing mission objectives were accomplished and the Servicing Mission
Observatory Verification (SMOV) period has begun.

Prior to the release activities, it was determined that two circuit cards
on the data interface unit #2 had failed on the spacecraft.  The STOCC
successfully reconfigured to the redundant (B) side of the unit.  The B
side of the unit operated nominally and the decision to release was made.

HST is in a sunpoint attitude under on-board computer control.  The health
and safety load is in process and is expected to begin execution tomorrow
afternoon.

=============================================================================

       HST Daily Report #1029
       December 11, 1993


       HST remains in a sunpoint attitude under on-board computer control.
All subsystems are nominal.  The STOCC is actively managing the
transponders and low gain antennas.

       All Pointing Control Subsystem hardware and software are performing
nominally.  Real-time trending of Gyro and MSS data shows normal
operating conditions.  In the last 24 hour period both high and low
gyro biases have been uplinked.  An attitude reference update (ARU)
was also uplinked to reduce the vehicle attitude RSS error to
approximately one third of a degree.  All the Fixed Head Star 
Tracker (FHST) maps performed following the ARU indicate that the attitude
has stabilized which is evidence of no uncompensated gyro bias drift.
All primary and backup collection of FHST/FHST alignment data has
been completed.  Preliminary results indicate that the tracker
to tracker alignments have not shifted relative to pre-servicing alignment.
 
       HST release from the shuttle occurred at 344/10:26:50 with RSS
"tip-off" rates of 0.054 deg/sec (V1 0.041 deg/sec, V2 0.033 deg/sec, and 
V3 0.012 deg/sec).  The maximum allowable "tip-off" rate was 0.2 deg/sec.
CSS data indicated an attitude error of approximately 3 degrees in both
V1 and V2 axes. HST software sunpoint capture occurred within 1 minute
20 seconds of RMS release.

       The power system is functioning properly with a peak current out of
the new solar arrays noted at 154 amps.

       The health and safety loads have been processed and are being
reviewed by all subsystems for approval before uplinking.  The first health 
and safety load will be uplinked this morning and will begin execution
at 4:00 pm this afternoon.

================================================================================


       HST Daily Report #1030
       December 12, 1993

       HST Servicing Mission activities continue as planned and all
subsystems are nominal.  The Health and Safety loads were uplinked 
yesterday and began execution as planned.  The HST is now operating under 
on-board computer control using ground generated command loads.  The first
STScI SMS has been received and loads are being processed.  These loads
will be uplinked after ground review and approval.  Execution is scheduled
to begin at 4:00 pm Monday.

       Telemetry formats "P" and "F" were loaded and verified.  Two DF-224
software patches were uplinked to correct the FGS acquisition logic
and to correct a database error in the attitude error threshold used for
computing the sequential attitude update (#44) command.  The latter
error was the cause of the majority of FGS loss of lock events since June
1993.  

       Nominal performance continues for all Pointing Control System 
(PCS) hardware and software.  The newly replaced gyros and magnetometers
continue to show normal behavior.  Currently, all six rate gyros are
powered on in low mode and drift rate biases are being computed from
star tracker mapping data.  Gyros 4, 5, and 6 are being used by the PCS
for attitude measurement.

       The HST has remained in normal mode and successfully performed 
+/- 1 degree slews about all three vehicle axes to verify gyro polarity.
Two attitude reference updates were uplinked, two low-mode gyro bias
updates were computed and uplinked, and one high-mode gyro bias update was
computed and uplinked.  Trends in the rate gyro biases are beginning
to show convergence to stable values.  The HST has maintained pointing
errors to within 300 arcseconds RSS.

       Power system performance has been nominal.  Average maximum 
battery capacity at the end of charge periods was 496 Amp hours.  Average
maximum solar output in full charge was 154 Amps.  Only K1 relays opened
during trickle charging periods.  All K2 relays remained closed.

================================================================================

       HST Daily Report #1031
       December 13, 1993

       The Space Shuttle Endeavour landed at Kennedy Space Center this 
morning at 12:30 am.

       HST Servicing Mission activities continue as planned and all 
subsystems remain nominal.  The HST continues to operate under on-board 
computer control using ground generated command loads.  The first STScI SMS 
based loads will begin execution this afternoon.

       Nominal performance continues for all Pointing Control System (PCS)
hardware and software.  All gyros and magnetometers continue to show
normal behavior.  The HST remains in normal mode with all six rate 
gyros powered on in low mode.  Gyros 4, 5, and 6 are being used by the PCS 
for attitude measurement.   Drift rate biases are being computed from 
star tracker mapping data.  The HST has maintained pointing errors to 
within 0.4 degrees RSS.

       Power system performance continues to be nominal.  The average 
maximum battery state of charge is 496 Amp hours with an average maximum 
solar array output current of 154 Amps.

STScI doesn't appear to be posting anything readable anymore, so I thought
I'd try to summarize what's going on:

Generally the SMOV (Servicing Mission Orbital Verification) activities are
progressing as planned, or within acceptable limits.

The gyros and magnetometers are working fine, the solar arrays are slewing
properly, etc.   There's been no explicit commentary if the solar array
"flapping" was eliminated with the new arrays.

Except for the WF/PC-II, I believe all the instruments have been turned on
and are testing out fine.   Calibration lamp tests last week went great and
some observations with the spectrographs is proceeding.

Outgassing/decontamination of the WF/PC-II is moving along, and low-voltage
startups are planned for the next few days.


Please note that the SMOV timeline has all the instruments running and checked
out without COSTAR first, so any early indications of aberration correction
are still a bit in the future.  The initial WF/PC-II calibration images 
are to adjust the pickoff mirror and are not expected to be great shakes.


- dave

    Last Wednesday afternoon on NASA Select there was a teleconference
    (No video, just audio) between a NASA team, HST team, & some others
    where they discussed for about an hour what their expected time-line
    of activities would be in the up-coming weeks. They said that this
    meeting would be a regularly scheduled meeting between these key
    team members, and that it would be scheduled for each Wednesday
    at noon cst. They said that it would be broadcast on NASA Select
    for other NASA sites to listen in on. There wasn't anything broadcast
    yesterday, so I'm not sure whether they didn't have the meeting or
    just held it without the benefit of also broadcasting it on NASA Select
    TV like they alluded to the week before. I'll try to make sure I tape
    the NASA Select coverage on Wednesday's in the up-coming wesks to see 
    if there is anthing worth transcribing here the following day.
    
    Bob

Article: 80155
From: [email protected] (Steven Pietrobon)
Newsgroups: sci.space.science,sci.space
Subject: COSTAR article
Date: 19 Dec 1993 22:32:14 GMT
Organization: Australian Space Centre for Signal Processing
Sender: [email protected] (Steven Pietrobon)
 
There is an excellent article on the COSTAR (Corrective Optics Space
Telescope Axial Replacement) that was recently installed on the Hubble
Space Telescope in a recent IEEE Spectrum. The reference is 
 
D. Hancock, "`Prototyping' the Hubble fix," IEEE Spectrum, vol. 30,
pp. 34-39, Oct. 1993. 
 
There are very good colour photos of the `virtual' COSTAR that was
used to test the clearances of the boom and arms of the COSTAR as they
were deployed. The author described how the software was used to find
that the hole where the FOC-M1 (Faint Object Camera Mirror 1) arm
deploys from was too small! This prevented a large delay had the
COSTAR gone into manufacture with the flaw. The software also picked
up that the FOC-M1 was partially blocking the light from the FOC-M2
into the FOC (this was also independently discovered by the optics
design team). You can see this in 3-D in Figure 4 of the article (Hold
your finger halfway between your nose and the the two stereo photos.
Focus on your finger. Move your finger back and forth until you see
three images. The middle photo is the combination of the left and
right images but will be blurred. The hard part is now to adjust the
focus of your eyes to that of the page without the left and right
images coming apart. This takes some practice as the position and
focus of your eyes are completely opposite to what they would normally
be. Warning: you may get a headache trying this.) 
 
The software also picked up another potentianlly serious fault that
could have masked very faint images with a haze of light. All these
faults were fixed before the COSTAR was manufactured and installed on
Hubble. 
 
-- 
Steven S. Pietrobon,  Australian Space Centre for Signal Processing
Signal Processing Research Institute, University of South Australia
The Levels, SA 5095, Australia.     [email protected]

From:	US1RMC::"ASTRO%[email protected]" "Astronomy Discussion 
        List" 29-DEC-1993 10:07:49.57
To:	Multiple recipients of list ASTRO <ASTRO%[email protected]>
CC:	
Subj:	Re: Hubble Telescope Repair

From Bill Gawne <[email protected]>

Brian Dickson <[email protected]> wrote:

>I was just wondering if anyone out there has heard anything more about
>the repair of the Hubble telescope since it was released.

Well, yes.

>I realize that it hasn't gone into use yet, but they must be testing
>it extensively now.  I have heard absolutly nothing about it on the
>news and was just curious if anyone out there has heard anything.

*General Disclaimer:  What follows is based on my own observations and  *
*opinions, and should in no way be interpreted as an official position  *
*or report by the STScI.  If I'm vague about some things its deliberate.*
*We're under some pretty strong restrictions about what we can say to   *
*anybody these days.                                                    *

In the early days of orbital reverification daily reports from Roger
Doxey (head guy with science instrument engineering here) were being
posted to sci.astro.hubble.  We're through with the engineering part
of SMOV (Servicing Mission Orbital Verification) now so Roger's reports
have ceased.

There is a SMOV timeline available via gopher at stsci.edu.  You'll have
to root around a bit to find it, or I can e-mail it if there's an interest.
If you have gopher capability try looking in the subdirectory stsci/hst-
reports.

Calibration of the science instruments and COSTAR is still in progress,
although since I'm in Operations Division I'm not free to discuss the
details of that.  In general, I'll allow there've been no surprises.
We currently expect to be taking some Early Release Observation images
in the Jan 5th to 10th timeframe.  Of course these images will have to
be de-biased and flatfielded, which all of you who've done that sort of
thing know takes some additional time.  You can expect the ERO's to be
released with suitable fanfare during the January AAS meeting in Washington.

The SMOV timeline is a 90-day calendar, and some SMOV activities will likely
continue past March.  The current plan is to start doing regular Cycle 4
science observations shortly after 1 Mar 94, assuming that everything
continues to go as well as it has so far.

-Bill Gawne
 HST Science Planning and Scheduling
 "We didn't build it, we just make it work."

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date:         Wed, 29 Dec 1993 09:50:39 -0500
% Sender: Astronomy Discussion List <ASTRO%[email protected]>
% From: Bill Gawne <[email protected]>
% Subject:      Re: Hubble Telescope Repair
% X-To:         [email protected]
% To: Multiple recipients of list ASTRO <ASTRO%[email protected]>

From:	US1RMC::"ASTRO%[email protected]" "Astronomy Discussion 
        List" 29-DEC-1993 10:12:26.47
To:	Multiple recipients of list ASTRO <ASTRO%[email protected]>
CC:	
Subj:	Re: Hubble Telescope Repair

NASA has implemented a news blackout concerning test images from HST.
The reason for this blackout is obvious-- the news media!

If they released the images that they have so far (test stars, flats, etc),
the media's (irresponsible) response would be "We paid HOW much for THAT?"

Not to mention that the deployment schedule for all of the new optics spans
weeks after the end of STS-61.

The rumors and hints that I've heard so far lead me to believe that every-
thing is going pretty well with the re-configuration and calibration tasks.

Let's hope for clear images and a responsible press/media!
(...well, at least ONE of the two!)

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date:         Wed, 29 Dec 1993 08:39:19 CST
% Sender: Astronomy Discussion List <ASTRO%[email protected]>
% From: Dennis Ward <ZU02308%[email protected]>
% Subject:      Re: Hubble Telescope Repair
% To: Multiple recipients of list ASTRO <ASTRO%[email protected]>

There's been a bit of a drought of HST status information over the holidays.
Some information has been peeking through and the operational status
reports appear to be flowing again.

All reports indicate that the telescope is performing fine and the SMOV and
alignment activities are progressing per plan.

COSTAR is deployed and alignment with the Faint Object Camera (FOC) is underway.
The fine alignment of these two instruments is next in the schedule.

WFPC-2 is still being turned on and decontaminated.  All data from the camera
is reported as normal.


- dave

I believe there is to be a press conference next week in which they will release
some images.  I saw the date/time, but I apparently did not save it.

Burns

 The Boston Globe had a story about it today. Rumor is that things are going
well and some really good pictures of the Orion Nebula should be out in about
a week.

  George

    The STS-61 mission press conference was shown on NASA on Tuesday.
    A reporter asked about whether any of the crew was having regular
    dialogue with the HST team folks. I think it was Jeff Hoffman who
    replied that yes they were, but did not allude to a specific time
    line for when pictures might be available. He only said that the
    HST Team has their work on-schedule and there aren't any significant
    problems which would prevent them from having some pictures by the
    end of January and maybe sooner.
    
    Bob

The issue of Aviation Week that arrived today (the Jan 3 issue) has a short
report and some sensational photos. The gyros and solar array drive electronics
have been checked out. WF/PC has been tested for contamination by photographing
a star in UV and found to be clean. (There apparantly was some concern because
the original camera picked up some contamination along the line.) The new solar
arrays reduced the night/day "twang" by 90%, Rockwell is in the process now of
simplifying the anti-twang program to free up more resources in the onboard
processor.

The report notes that the servicing operation was much less traumatic for Hubble
than expected. For example, despite the problems the astronauts had closing the
aft shroud doors which cover the fixed head star trackers, the trackers, when
tested, showed no signs of being disturbed. No matter what else, the mission
demonstrated that large scale on-orbit servicing is very feasible.

Mike H.

in .-1 I mentioned Rockwell. That should have been Lockheed. MH

SMOV activities are reported to be either on-time or slightly ahead of
schedule.

COSTAR - FOC (Faint Object Camera) alignment and focusing activities are
proceeding on target.

WF/PC-II has made several observations of external targets (as reported
earlier in this string):

       The WF/PC-2 was used to make observations of NGC-1976-ER which is
       located in the Orion Nebula (aka, M-42). Several short exposures
       were taken, using two different filters. The objective was to study
       fine scale turbulence in the nebula. A total of six observations
       were received and displayed.

       The WF/PC-2 was used to make observations of inner regions of the
       spiral galaxy M-100 (aka, NGC-4321) which is located in the Virgo
       Cluster. The intent is to resolve individual stars within the
       galaxy. A total of seven images were received and displayed. The
       guide star reacquisition was still in process when the first
       observation began. All images were reported to be okay.

Astrometric observations using the FGS (Fine Guidance Sensors) is also
proceeding. [The FGS array has a dual purpose of doing science as well.]


The FOC was used to take some images prepping for the early release images:

       The Faint Object Camera (f/96) was used to make observations of the
       ejecta from Super Nova SN-1987A to monitor its evolution.
       Observations were taken with several different filters. A SIP
       corrective maneuver was successfully uplinked to the spacecraft. A
       total of nine images were received and displayed.

       The Faint Object Camera was used to make narrow band ultraviolet and
       optical observations of the environment around Nova Cygni 1992A. A
       SIP corrective maneuver was successfully uplinked to the spacecraft.
       One of the images was reported to be over-exposed. All the other
       images were reported to be satisfactory.


- dave

WF/PC-2 fine alignment and focusing activities continuing.  The targets
mentioned tend to be ones that have both visible and UV outputs so they can
calibrate the response of the optics and the CCDs over the range of
frequencies.

COSTAR/FOC alignment continues as well.



There is a news conference today which will unveil some early release images
to the public.   I'm sure they'll be scanned in by somebody and we'll have
them available both in the archives and on the Web.    Media reports indicate
that the repairs have indeed worked and the HST is performing well.


- dave

Sarah Keegan
Headquarters, Washington, D.C.                                                
January 13, 1994
(Phone:  202/358-1547)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)

RELEASE:  94-7

NASA DECLARES HUBBLE SERVICING MISSION SUCCESSFUL

NASA Administrator Daniel S. Goldin today declared that last month's 
Space Shuttle mission to service the Hubble Space Telescope (HST) had 
been fully successful in correcting the vision of the telescope's optical 
components.  The announcement, accompanied by the first new images from 
HST, followed the initial 5 weeks of engineering check-out, optical 
alignment and instrument calibration. 

Word of the Hubble success came at a press conference at NASA's Goddard 
Space Flight Center, Greenbelt, Md.  Goldin was joined in making the 
initial announcement by Dr. John H. Gibbons, Assistant to the President 
for Science and Technology, and Senator Barbara A. Mikulski (Md.), Chair, 
Appropriations Subcommittee on VA, HUD and Independent Agencies. 

"This is phase two of a fabulous, two-part success story," Goldin said.  
"The world watched in wonder last month as the astronauts performed an 
unprecedented and incredibly smooth series of space walks.  Now, we see 
the real fruits of their work and that of the entire NASA team. 

"Men and women all across this agency committed themselves to this 
effort.  They never wavered in their belief that the Hubble Space 
Telescope is a true international treasure," Goldin said. 

Mikulski, who unveiled two new HST pictures at the press conference, 
said, "I am absolutely delighted that Hubble is fixed and can see better 
than ever.  This is tremendous news. 

"Now we are going to look at the origins of our universe, "Mikulski said.  
"What a wonderful victory this is for the Hubble team of astronauts, 
astronomers, scientists and engineers.  Together they are moving American 
science and technology into the 21st century with exciting new 
opportunities for scientific and economic progress." 

Pictures were released from the two cameras that received corrective 
optics during the servicing mission -- the Wide Field/Planetary Camera II 
and the European Space Agency's Faint Object Camera.  

Here they are...  On the Web (or will be in a few minutes), plus...

  pragma::public:[nasa]wfpc-new-XX.gif

01     114K    Hubble/WFPC-II image M100 galaxy before/after 1/13/94
02     119K    Hubble/WFPC-II image M100 galaxy and inset 1/13/94
03     183K    Hubble/WFPC-II image M100 Cepheid stars 1/13/94
04     114K    Hubble/WFPC-II image R136 cluster and inset 1/13/94
05     105K    Hubble/WFPC-II image star ground/before/after 1/13/94
06     126K    Hubble/WFPC-II image Eta Carinae 1/13/94

More later...

- dave

From: [email protected] (DOUGLAS A. LEVY, UPI Science Editor)
Copyright: 1994 by UPI, R
Date: Thu, 13 Jan 94 12:55:48 PST

        GREENBELT, Md. (UPI) -- Beaming NASA scientists and managers Thursday
unveiled evidence that the $2 billion Hubble Space Telescope no longer
suffers from fuzzy vision.
        ``The Hubble is fixed,'' said program scientist Ed Weiler. ``It is
fixed beyond our wildest expectations.''
        NASA Administrator Daniel Goldin said repairs by the shuttle
Endeavour crew last month worked perfectly to correct the telescope's
blurred optical system and wobbly solar power wings.
        ``It's exceeding our goals,'' Goldin said. ``The spacecraft is
operating beyond our expectations. Everyting we know today says we are
OK.''
        A photograph of the spiral galaxy M100 taken by the Hubble's Wide
Field Planetary Camera 2 on Dec. 31 showed minute details of the
galaxy's bright core and the stars and gas clouds surrounding it -- an
estimated 50 million light years from Earth.
        A comparison picture taken by the original camera in November, before
NASA's ambitious repair mission, was blurry and less detailed.
        ``When that image came up, even us skeptics believed we had fixed it,
'' Weiler said.
        Astronomers also got their best look yet at the gas shell surrounding
Nova Cygni 1992, which erupted in a thermonuclear explosion on Feb. 19,
1992, over 10,000 light years away, NASA officials said. The image was
taken by the European Space Agency's Faint Object Camera on board the
Hubble telescope.
        Senior Hubble scientist Dave Leckrone said the orbiting telescope was
operating ``like a dream.''
        ``We've had to devote no time whatsoever to troubleshooting,'' said
Leckrone, at a news conference at NASA's Goddard Space Flight Center,
near Washington, D.C.
        ``The trouble with Hubble is over,'' said Sen. Barbara A. Mikulski,
D-Md., who chairs the Senate subcommittee that oversees the space
agency's budget. Mikulski called the new pictures ``remarkable.''
        Mikulski unveiled photographs that were taken from Hubble during the
past five weeks of checking on engineering, optical alignment and
instrument calibration since repairs to the giant telescope were made by
the the shuttle Endeavour's astronauts.
        Astronauts installed new, upgraded equipment and corrective mirrors
to fix an error in the original lens installed on the Hubble telescope
before its launch in 1990.
        James Crocker, the Space Telescope Science Institute manager who
first proposed the corrective optics system installed on the Hubble,
said the rejuvenated telescope now was strong enough to detect a firefly
in Tokyo from as far away as Washington.

    How about some picrtures of Mars so we can lay to rest the faces and
    pyramid claims. 

I don't believe that even the theoretical angular resolution of HST could
achieve such a feat -- the Mars Observer cameras could have easily done
so.

Remember, all this face nonsense comes from Viking Orbiter pictures taken
a few hundred miles up.

- dave

re .388
    
>I don't believe that even the theoretical angular resolution of HST could
>achieve such a feat
    
    In support of this assertion see 565.5 which lists the best resolution
    of HST at Mars as 8 miles, clearly not good enough for even large
    "buildings".

I finally found the FOC (Faint Object Camera) images that were released.

Available via the Web from the same location.  Also available are the
WFPC-2 images with some informative captions.  I have kept both sets
available.

The files are also available the old fashioned way from pragma::public:[nasa]

The new FOC images:

psfcomparison-jan94.gif  PSF comparison with caption.
ngc1068core-jan94.gif    FOC image of core of Seyfert galaxy NGC1068.
novacyg-jan94.gif        FOC image of expanding shell around Nova Cygnus
                         compared to image taken last year (shell has expanded)

Captioned WFPC images (no new images, just repackaging of the original set):

doradus-jan94.gif        R136 again, but with caption.
focpsfs-jan94.gif        Another PSF comparison.
m100wcaption-jan94.gif   M100 again, with caption.

- dave

Where on the Web are these located?  I tried STSCI or whatever, as the 
most likely place, but didn't see these at first.  Last time I tried,
I had trouble getting into ST institute.

Thanks,
PeterT

    Hi,
    
    Can someone please enlighten a novice and tell me what the object is
    in WFPC-NEW-06. Is this the new cassiopeian nova....? Was that a 
    stupid question....?
    
    Gav$lots_to_learn_still

I believe WFPC-NEW-O6 is the nebula Eta Carinae, which is, I believe, 
a southern hemisphere object.  It certainly looks like a nova, supernova
remnant, but it could be something else.  It is not the new nova.

PeterT

An interesting tidbit from a recent HST status report that I thought
people would be interested in...


   1.3 Completed FOC/96 5150 (Pluto and Charon)

       The Faint Object Camera (f/96) was used to make observations of the
       planet Pluto and its moon Charon. Pluto was reported to subtend 10
       pixels, and Charon about 5. The two bodies were separated by about
       30 pixels. Four images were received and displayed. The images were
       reported to be excellent!

I hope the investigators are kind and release it early (rather than the 1 year).


- dave

    30 pixels separating them?!  They were never more than an elongated
    blur before, were they?
    
    Burns
    

Article: 52872
Newsgroups: sci.astro
From: [email protected] (Chris O'dea)
Subject: Early Release Observations from Hubble Space Telescope
Sender: [email protected]
Organization: Space Telescope Science Institute
Date: Fri, 18 Feb 1994 22:48:32 GMT
 
EARLY RELEASE OBSERVATIONS: PROPRIETARY SITUATION
-------------------------------------------------
 
The intent of this memo is to clarify the proprietary situation
concerning the so-called "Early Release Observations", or ERO, and to
announce the public release of a subset of the data. The imaging
program is now complete, and is summarized below.
 
All observations which were obtained under the auspices of the ERO
program were drawn from existing science programs, both GO and GTO,
although the ERO program itself is separate from those science
programs.  It was agreed early in the process of soliciting input for
the program that in such an eventuality, and in contrast to the
previous ERO/SAT exercise after launch, that the ERO data would be
subject to the normal proprietary restrictions for a science program
(i.e. one year after the data are obtained) and that the proprietary
rights would belong to the PI of the science program. The PIs all
agreed to release images of their data in the form of press releases
and postings of gif files etc. on steis.
 
There is some sympathy however amongst the scientists involved that a
subset of the data should be made available for public release either
immediately or with a shortened proprietary period.  This will allow
people to improve their familiarity with the current HST and its
instrumentation and assist in Cycle 5 proposal writing.  In addition,
SMOV calibration data will also be released following a very short
proprietary period and this too will offer an opportunity for
interested parties to obtain hands-on experience of working with WFPC2
and COSTAR related data.
 
The list below summarizes the current situation for the ERO.  It is
complete and there will be no further observations obtained under this
program. When there are additional releases, notices will be posted to
that effect also on steis.
 
If you require access to publically available data, please contact
[email protected].
 
ERO PI list, proposal numbers and proprietary situation:
--------------------------------------------------------
 
WFPC2
 
Orion    5193  Bob O'Dell           F547M, 2 images public now.
QSO host 5502  John Hutchings       1 yr
CL0939   5190  Alan Dressler        Three month proprietary period
M100     5195  Jeremy Mould         F555W one epoch; 4 images public now.
Eta Car  5188  Jim Westphal         1 yr
R136     5589  John Trauger         1 yr
 
FOC/COSTAR
 
SN1987A  5186  Peter Jakobsen       1 yr
47 Tuc   5191  Francesco Paresce    1 yr
NGC1068  5578  Duccio Macchetto     1 yr
Nova Cyg 5577  Francesco Paresce    1 yr
 
FOS/COSTAR
 
M87      5267  Richard Harms        1 yr
 
GHRS/COSTAR
 
R136 s 1 5297  Sally Heap   ***     1 yr
 
*** Not yet obtained
 
-- 
  +--------------------------------------------+-----------------------+
  | Chris O'Dea                                | [email protected]        |
  | Space Telescope Science Institute          | Phone (410) 338-2590  |
  | 3700 San Martin Drive, Baltimore, MD 21218 | Fax   (410) 338-5085  |
  +--------------------------------------------+-----------------------+ 

        "Philosophy is useless.  Reality is worse."  (Dire Straits)
 

  I think someone tried to explain it to me once but I forget. Just how is the
public served by giving a few scientists exclusive rights to these pictures for
such a long time? A couple weeks ok, but a full year? Somehow I don't see the
benefit to the tax payers who paid for all of this. 

  George

It is a *big* debate and somewhat a matter of philosophy...

The story goes that the people who have spent literally YEARS of their
time designing, building, testing, and characterizing the instruments
of a satellite have earned a right to keep the data gathered by those
instruments so that they can reap the rewards of their efforts.

Public funding of these activities seems to be a bigger part of the argument:
if you accept public funds then you "lose" that right.

In the "publish or perish" atmosphere of astronomy (and other sciences)
such predatory behavior seems understandable and "unscientific" at the
same time.  Toss in our tax bucks and it gets more complicated.   Toss in
that HST is a part US part European venture and it probably gets worse.

A few observatories have dispensed with the rights and distributed the data
almost immediately (subject to archiving and other delays).  They seemed to
be happy with the arrangements -- I guess nobody's pet project was stomped
on by an outsider.


- dave

On the other hand, when you are studying something like astronomy, whose
immediate impact on the lives of nearly every living thing on this planet
approaches zero, and represents a field whose history is probably longer
than recorded history itself -- what's a lousy 365 days?  Regardless of
who pays for it?

I recommend we create a separate topic (possibly in the Astronomy notes 
conference) if there is any significant interest...


- dave

[... that at least I can relate to!]


   1.5 Completed Two Sets of WF/PC-2 5392 (Mapping Io's Surface and
       Volcanic Activity: Cycle 4 Medium)

       The WF/PC-2 was used to make images of the surface of Jupiter's moon
       Io to study changes since the Voyager Mission and before the Galileo
       Mission. Images were made before and during an eclipse of Io which
       occurred at 065/0419Z. The images were reported to be nominal.

From:	VERGA::US1RMC::"[email protected]" "23-Mar-1994 0944" 23-MAR-1994 
To:	distribution:;@us1rmc.bb.dec.com 
CC:	
Subj:	1994 HUBBLE FELLOWS SELECTED

Contact:  Cheryl Gundy        For Release:   March 28, 1994
          410-338-4707                                 
                              Press Release No.:  STScI-PR94-14

               1994 HUBBLE FELLOWS TO STUDY HST DISCOVERIES

The Space Telescope Science Institute (STScI) has recently selected 11
young scientists for the 1994 Hubble Postdoctoral Fellowship Program. 
The awardees were selected from a pool of applications from
highly-qualified candidates worldwide. 

Inaugurated in 1990, the Hubble Fellowship Program funds research
opportunities for a significant fraction of the approximately two
hundred Ph.D. astronomers who graduate annually.  The program is a
joint venture between NASA and STScI in cooperation with astronomical
institutions across the United States. 

The scientists selected for this program will have an opportunity to
conduct Hubble Space Telescope (HST)-related research of their choice
at participating astronomical institutions throughout the U.S. In
order to avoid an excessive concentration of talent at any one
astronomy institution, no more than one Fellow per year is approved
for any one place.  New Hubble Fellows are added each year, for
three-year terms.  The program currently supports a pool of several
dozen astronomers. 

Candidates are selected each year through a review by a nine-member
panel composed of eminent scientists from U.S. institutions, which
ranks them on the basis of merit (research proposal, publications,
academic achievements), after which the STScI Director or his
designate makes final selection.  On completion of the Fellowship
Program, these young astronomers are expected to go on to
professorships at major institutions. The Hubble Fellowship Program is
expected to play an important role in expanding and strengthening the
astronomical community. 

"The Hubble Fellowships not only fund excellent scientific research,
but also bring the best and brightest into the nation's centers of
higher education," said Peter Stockman, deputy director of STScI. "We
expect that many of the Hubble Fellows will become tomorrow's top
scientists and educators." 

The 1994 Hubble Fellowship recipients are:  Michael E. Brown, Lunar
and Planetary Laboratory, Houston, Texas; Julianne Dalcanton,
Observatories of the Carnegie Institution of Washington, Pasadena,
California; Todd J. Henry, Space Telescope Science Institute,
Baltimore, Maryland; John E. Hibbard, Institute of Astronomy,
University of Hawaii, Honolulu, Hawaii; Lynne A. Hillenbrand,
University of California, Berkeley, Berkeley, California; and Victoria
M. Kaspi, Jet Propulsion Laboratory, Pasadena, California. 

Other recipients are:  Limin Lu, California Institute of Technology,
Pasadena, California; Suzanne T. Staggs, University of Chicago,
Chicago, Illinois; Julie A. Thorburn, Yerkes Observatory, Williams
Bay, Wisconsin; Roeland P. van der Marel, Institute for Advanced
Study, Princeton, Princeton, New Jersey; and Guy S. Worthey,
University of Michigan, Ann Arbor, Michigan. 

                              *  *  *  *  *  *

The Space Telescope Science Institute is operated by AURA (the
Association of Universities for Research in Astronomy, Inc.) for NASA,
under contract with the Goddard Space Flight Center, Greenbelt, MD. 
The Hubble Space Telescope is a project of international cooperation
between NASA and ESA (the European Space Agency). 

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Wed, 23 Mar 1994 09:29:51 -0500 (EST)
% From: [email protected]
% Subject: 1994 HUBBLE FELLOWS SELECTED
% To: distribution:;@us1rmc.bb.dec.com

Article: 55106
Newsgroups: sci.astro
From: [email protected] (Stupendous Man)
Subject: HST programs to seek planets (Bonus! HST looks at Pluto)
Sender: [email protected] (USENET News System)
Organization: Princeton University
Date: Sat, 26 Mar 1994 02:34:22 GMT
 
  Okay, I've done a little snooping over the Internet and found the
following information on HST Programs to look for planetary -- or,
at least, low-mass stellar -- companions.
 
  First, there's a program (PI Schroeder) which is looking for
companions to HD 22049, using the PC of WF/PC II.  They use red and
near-IR filters, and got a bunch of exposures a few weeks ago.
 
  Second, there's a program (PI Barbieri) which uses FOC to look
for companions to nearby stars.  They've looked at GL 1245 recently,
and (probably) plan to look at several others.  The narrow-band filter
they mention below is centered at 4860 Angstroms.  Here's the proposal
abstract:
 
Prop. Type:  GTO/FOC
 
               STELLAR POPULATIONS    -- (
FC08 - "DETECTION OF FAINT COMPANIONS TO NEARBY STARS"
     Keywords : STARS,SUB-STELLAR MASS COMPANIONS
     Proposers: Cesare Barbieri (PI; Padova, University Of; Italy),
                F.Macchetto (ESA, Space Telescope Science Institute)
 
     The program aims at detecting companions of substellar masses in nearby
     stars with evidence of duplicity coming from:

     - astrometric perturbations
     - radial velocity variations
     - infrared speckle data

     The FOC is uniquely capable to resolve the faint companion because of its
     photon counting mode and excellent optical quality.
     The search will be conducted mostly using a narrow-band filter in order
     to take advantage of the best possible PSF, and to
     attenuate saturation effects in the primary;
     the choice of this band is aimed also at obtaining a good indication of 
     the temperature of the secondary, when infrared data are available.
 
-----------------------------------------------------------------------------
 
  Third, there's a program to use the FGS to look for low-mass
companions via the astrometric perburbations on the primary star. This
one has gotten several observations lately, too, of stars AC+48D1595,
VA 472, and VA 72 (don't ask me which ones those are :-)). Here's the
proposal abstract: 
 
Prop. Type:  GTO/AST
 
               SOLAR SYSTEM          -- (
4031- CT - "HIGH SPEED ASTROMETRY - A SEARCH FOR PLANETARY COMPANIONS TO
                LOW-MASS STARS CYCLE ONE - NEW AND IMPROVED"
     Continuation of Program Number  2939
     Keywords : FINE GUIDANCE SENSORS, FGS, STELLAR COMPANIONS, EXTRASOLAR
                PLANETS
     Proposers: William H. Jefferys (PI; University Of Texas), G.Benedict
                (University Of Texas), R.Duncombe (University Of Texas), O.Franz
                (Lowell Observatory), L.Fredrick (University Of Virginia),
                P.Hemenway (University Of Texas), P.Shelus (University Of Texas)
 
     We propose to test the hypothesis that Jupiter-like planets are formed at
     distances from the primary dictated by the 'freezing' temperature of the
     volatiles which comprise jovian planets. Predicted periods for jovian
     planets orbiting this sample of very late-type, low-mass stars range from
     70 to 160 days. We shall monitor the positions of these nearby late-M stars
     with a time-resolution of 4 to 10 days in an attempt to detect positional
     perturbations caused by possible jovian companions. Detection limits for
     these proposed targets lie between 0.4 and one Jupiter mass.
 
-----------------------------------------------------------------------------
 
  Finally, to round out this message, since someone earlier mentioned
HST observations of Pluto, here's a proposal which is scheduled to do
so.  I guess I'm not up on the latest image-analysis software, because
my understanding is:
 
                   - the FOC Airy disk is ~0.08 arcsec in diameter
                   - Pluto is 0.08 arcsec in diameter
 
and so it strikes me that discerning anything more than "Pluto is not
a perfect point source" will be, um, difficult.  Anyway, here's the abstract.  
 
 Prop. Type:  GTO/FOC
 
               MINOR PLANETS    --  (
FC09 - "HIGH RESOLUTION IMAGING OF MINOR PLANETS"
     Keywords : ASTEROIDS, PLUTO
     Proposers: Cesare Barbieri (PI; Padova, University Of; Italy)
 
     The purpose of this investigation is to determine shapes, spin axis
     orientation and surface details of the largest asteroids. In addition,
     Pluto will be imaged. The diameter of the planet is approximately 8 pixels,
     so that given the improved image quality, it is possible to resolve surface
     details (if the brightness modulation is greater than approximately 5%)
     without resorting to unduly complex algorithms.
 
-----------------------------------------------------------------------------
 
  My thanks to the Space Telescope Science Institute for their great
public-access system!  It's exciting to see science in action!
 
-- 
-----                                                    Michael Richmond
"This is the heart that broke my finger."    [email protected]
 
Article: 55203
Newsgroups: sci.astro
From: [email protected] (Daniel Briggs)
Subject: Re: HST programs to seek planets (Bonus! HST looks at Pluto)
Organization: National Radio Astronomy Observatory, Socorro NM
Date: Mon, 28 Mar 94 01:33:53 GMT
 
In article <[email protected]>
  [email protected] (Stupendous Man) writes:
 
>Prop. Type:  GTO/FOC
>
>               STELLAR POPULATIONS    -- (
>FC08 - "DETECTION OF FAINT COMPANIONS TO NEARBY STARS"
>     Keywords : STARS,SUB-STELLAR MASS COMPANIONS
>     Proposers: Cesare Barbieri (PI; Padova, University Of; Italy),
>                F.Macchetto (ESA, Space Telescope Science Institute)
>
>     The program aims at detecting companions of substellar masses in nearby
>     stars with evidence of duplicity coming from:
>     - astrometric perturbations
>     - radial velocity variations
>     - infrared speckle data
 
I presume they mean that they'll also be using ground based IR speckle
data?  Is "evidence of duplicity" some catch phrase that I don't
recognize? I can almost torture the phase into "auxiliary evidence",
but it's not clear. 
 
-- 
| Daniel Briggs  ([email protected])                        |  USPA C-23367
| New Mexico Tech / National Radio Astronomy Observatory   |      DoD #387
| P.O. Box O / Socorro, NM 87801   (505) 835-7391          | 
| Dart:	MC Ot+W H 3 Y L+ W C+ I++ T++ A+ H+ S+ V+ P++/P B+ |

From: [email protected]
Newsgroups: sci.astro.hubble
Subject: HST Status Report, 04/06 - 04/07
Date: Thu, 7 Apr 1994 15:37:48 GMT
Organization: Space Telescope Science Institute
 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1112
 
PERIOD COVERED:  0700 EST 04/06/94 - 0700 EST 04/07/94
 
Daily Status Report as of 097/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats,
       Large Set)
 
       The WF/PC-2 was used to make a set of Earth flat calibration images
       using different filters in order to construct high quality flat
       fields of the OTA illumination pattern. A total of eight images were
       received and displayed. One image was reported to be underexposed,
       two were saturated, and the other five were okay.
 
   1.2 Completed Two Sets of WF/PC-2 5562 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor 3: Darks)
 
       The WF/PC-2 was used to obtain two 30-minute long, dark exposures
       to provide ongoing calibration of the CCD dark current and to
       monitor and characterize the evolution of hot pixels. Both images
       were received and displayed in the OSS. They were reported to look
       nominal.
 
   1.3 Completed Two Sets of WF/PC-2 5476 (Continuum Snapshots of 3CR Radio
       Galaxies)
 
       The WF/PC-2 was used to make snapshot images of radio galaxy 3C181.0
       and 3C299.1 as part of a continuum survey and to study the galaxies'
       morphology. Two images were received and displayed. Both were
       reported to look nominal.
 
   1.4 Completed WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 2 : Flats)
 
       The WF/PC-2 was used to make a visual flat calibration images to
       monitor flat field stability and the stability of the
       analog-to-digital converters. Five observations were monitored by
       the OSS. All five images were reported to be saturated.
 
   1.5 Completed FGS 5054 (High Speed Astrometry: A Search for Planetary
       Companions to Low Mass Stars)
 
       The  Fine Guidance Sensors were used to make observations of the
       position of the star Proxima Centauri to determine the presence of a
       Jupiter sized planet in orbit about the target star. The Baseline
       guide star acquisition failed to make fine lock on FGS #1 and #2. It
       did make course track on FGS #1. The remaining time under this
       guiding period was all during LOS, and could not be monitored in
       real time.
 
   1.6 Completed WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
       The WF/PC-2 was used to make observations taken in parallel with the
       prime science observations. This is part of a survey to take
       pictures of a large number of fields within 30 degrees of the
       galactic plane. The intent is to determine the luminosity function
       of low mass stars and the mass density in the solar neighborhood.
       The observations were executed as scheduled, and no anomalies were
       noted.
 
   1.7 Completed Two Sets of FGS 5134 (Extragalactic Astrometry and
       Astrophysics: FT12-23, Part 2 of 2)
 
       The FGSs were used to make astrometric observations of five
       different stars to tie the HIPPARCOS and extragalactic reference
       frames together. Most of the targets in this set of observations
       were successfully acquired and observed. Two targets failed to be
       located, and the Stop Flag was set. About half of the observations
       occurred during LOS. The observations which could be monitored were
       reported to be nominal.
 
   1.8 Completed FGS 5174 (Astrometric Companion Search: Cycle 4)
 
       FGS #3 was used to make astrometric observations of the possible
       binary dwarf star BD+68D946 to look for an astrometric unseen low
       mass companion. The OSS monitored the observations and assessed the
       data quality. No anomalies were noted.
 
   1.9 Completed WF/PC-2 5091 (GTO High Latitude Parallel Program: Cycle 4)
 
       The WF/PC-2 was used in parallel with the prime science observations
       to make high galactic latitude observations greater than +/-30
       degrees. These are randomly chosen fields to sample very low
       luminosity stars in the solar galactic neighborhood, galactic halo
       objects, and distant galaxies. The science observations remains on
       the science tape recorder, and will be analyzed later. No anomalies
       were noted.
 
   1.10 Completed WF/PC-2 5324 (Globular Cluster Core Imaging)
 
       The WF/PC-2 was used to make images of the central region of globular
       cluster NGC-7078 (aka, M-15). The OSS monitored the observations.
       The data remains on the science tape recorder. No anomalies were
       noted.
 
   1.11 Completed FOS/BL 5530 (FOS Location of Spectra and Aperture)
 
       The Faint Object Spectrograph (Blue Side) was used to make Y-base maps
       of the FOS detectors using internal lamps. The purpose is to
       determine the location of the spectra on the diodes. The
       observations were executed as scheduled, and no anomalies were
       noted.
 
   1.12 Completed WF/PC-2 5351 (Properties of Intermediate Redshift
       Galactic Disks Causing Damped Ly-Alpha)
 
       The WF/PC-2 was used to make observations to study the diffuse
       material at intermediate redshifts that is identified by absorbing
       Lyman-Alpha spectrum from quasar PKS0454+03. The observations were
       executed as scheduled, and no anomalies were noted.
 
   1.13 Completed GHRS/1 5413 (The Local ISM Flow Within the Heliosphere)
 
        The High Resolution Spectrograph was used to make observations to
        study the flow of neutral atoms in the interstellar medium by
        observing diffuse sky background in Lyman Alpha. The observations
        were executed as scheduled, and no problems were noted.
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions : 9
                                        Successful : 8
 
        A guide star acquisition failed to course track at 096/1632Z. The
        scan step limit was exceeded. FGS #1 went to course track.
 
 
                          Scheduled Reacquisitions : 6
                                        Successful : 6
 
   2.2 FHST Updates:
 
                              Scheduled :18
                             Successful :18
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes:
 
       An uneventful day was experienced as each HST subsystem reported
       anomaly-free operations.
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Two Sets of WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 2: Flats)
 
   3.2 Complete WF/PC-2 5404 (Narrow-Band Imaging fo Hydrogen-Poor
       Planetary Nebulae Cycle 4 High)
 
   3.3 Complete WF/PC-2 5475 (A Snapshot Survey for Blue Stragglers in
       Magellanic Cluster Cores)
 
   3.4 Complete WF/PC-2 5415 (The Distance to the M-96 Galaxy Cluster:
       Cycle 4 Medium)
 
   3.5 Complete WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats,
       Large Set)
 
   3.6 Complete GHRS/2 5358 (The Chromosphere of Alpha Tau: Cycle 4 Medium)
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       Nothing at this time.
 

From: [email protected] (HST Newsgroup)
Newsgroups: sci.astro.hubble
Subject: Status Reports and Recentering Events
Date: 7 Apr 1994 21:47:07 GMT
Organization: College of Liberal Arts and Sciences, ASU
 
There have been numerous requests from the readership concerning the
recentering events noted in the OSS status reports posted here daily.  To get
the official word I contacted sources at STScI to confirm what I thought they
were and here are the details.
 
During an exposure, the position of the telescope's pointing is continuously
checked through the FGS sensors and due to creaking and small motions these
pointing fluctuations are deemed acceptable if they are less than 20
milliarcseconds in pitch and yaw, and 200 mas in roll.  If these limits are
exceeded then a "recentering event" is noted as the gyros compensate for the
departure to bring the pointing back inside the "safe" box.
 
Recall that for WFPC-2, one pixel is about 44 mas in the PC and 100 mas in the
WFC's.  Therefore, a roll recentering event (about the V1 axis) might result
in a deformation of a circular stellar image in the direction of the
departure.  The length of these departures is short, a few seconds, and so it
would only be a big effect, relatively, for a shorter exposure.
 
If the departure presists for more than a few tens of seconds then the event
becomes a loss of lock, and more forceful pointing correction methods have to
be employed and a possible compromise of the data could happen.
 
In summary, the recentering events are in general merely a note of a small
departure from "ideal" or "perfect" pointing for the telescope, and only in
rare cases do they affect the data taken.  Loss of lock events are more
serious and could affect the quality of the data.
 
--
--------------------------------------------------------------------------------
HST newsgroup - Moderator:
Paul A. Scowen				INTERNET: [email protected]
Department of Physics & Astronomy		
Arizona State University		Tel:      (602) 965-0938
Tempe, AZ 85287-1504			FAX:      (602) 965-7954
--------------------------------------------------------------------------------

    I found a summary of HST observations to date on USENET, but it is
    in a wide format. It is also several thousand lines long.

    I originally thought to post it, but because it is wide (132 columns)
    it would not really do well in Notes. If I edited it, or wrapped the
    lines to fit on-screen...well...goo info would be lost and it would
    look funny.

    So, I placed it in the following location for any who are interested:

    CXDOCS::SYS$PUBLIC:HST_OBSERVATIONS.TXT

    Its about 837 blocks.

    Enjoy!

    Regards,

    John B.

From: [email protected]
Newsgroups: sci.astro.hubble
Subject: HST Status Report, 04/07 - 04/08
Date: Fri, 8 Apr 1994 15:11:57 GMT
Organization: Space Telescope Science Institute
 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1113
 
PERIOD COVERED:  0700 EST 04/07/94 - 0700 EST 04/08/94
 
Daily Status Report as of 098/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed Two Sets of WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 2: Flats)
 
       The WF/PC-2 was used to make a visual flat calibration images to
monitor flat field stability as well as the stability of the 
analog-to-digital
converters. The observations were monitored by the OSS, and no anomalies
were noted.  The data has not yet been analyzed due to problems with ground
receipt.  A LOR from WSGT is expected.
 
   1.2 Completed WF/PC-2 5404 (Narrow-Band Imaging fo Hydrogen-Poor
       Planetary Nebulae Cycle 4 High)
 
       The WF/PC-2 was used to make narrow band images of the small
dynamical structure  of the hydrogen-poor planetary nebula IRAS1833-2. This
nebula contains gas that consists of nearly undiluted products of the
nuclear burning that is thought to result when a final helium shell flash
occurs after the complete removal of the hydrogen envelope. Four images
were received and displayed. No anomalies were noted.
 
   1.3 Completed WF/PC-2 5475 (A Snapshot Survey for Blue Stragglers in
       Magellanic Cluster Cores)
 
       The WF/PC-2 was used to make short exposure snapshot images of the
blue straggler stars located in populous cluster NGC-339. A populous
cluster is the Magellanic Cloud equivalent of a galactic globular cluster.
The observations were made with two different color filters. The intent is
to find out if blue straggler stars exist within these clusters. Both of 
the
images were received and displayed. They were reported to look nominal.
 
   1.4 Completed WF/PC-2 5415 (The Distance to the M-96 Galaxy Cluster:
       Cycle 4 Medium)
 
       The WF/PC-2 was used to make observations of Cepheid variable stars
within the galaxy NGC-3368 which itself is located in the M-96 galaxy
cluster. This is to help determine the distance to this galactic group, and
to improve the determination of the Hubble constant. The observations were
received and displayed. No anomalies were noted, although full analysis is
pending receipt of the STR dump.
 
   1.5 Completed WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats,
       Large Set)
 
       The WF/PC-2 was used to make a set of Earth flat calibration images
using different filters in order to construct high quality flat fields of
the OTA illumination pattern. The OSS monitored the observations and
assessed the data quality. No anomalies were noted.  Of the 8 exposures, 4
were underexposed and 1 was saturated.
 
   1.6 Completed GHRS/2 5358 (The Chromosphere of Alpha Tau: Cycle 4
       Medium)
 
       The High Resolution Spectrograph (Side Two) was used to make
spectroscopic observations of the chromosphere of the star Alpha Tauri. The
baseline guidestar acquisition failed to make fine lock.  The observations
continued in coarse track.  The onboard target acquisition probably
succeeded.  No problems were noted.  All data remains on the STR.
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions : 4
                                        Successful : 3 (failure at 
097/2213Z;
FGS#3 failed to acq;
remained in coarse
track)
                          Scheduled Reacquisitions : 9
                                        Successful : 9
 
   2.2 FHST Updates:
 
                              Scheduled :11
                             Successful :11
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes: There were no significant reported problems in any
 HST subsystem.
 
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Three Sets of WF/PC-2 5475 (A Snapshot Survey for Blue
       Stragglers in Magellanic Cluster Cores)
 
   3.2 Complete Two Sets of WF/PC-2 5562 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor 3: Darks)
 
   3.3 Complete FGS 5333 (Linking the HIPPARCOS to the Extragalactic
       Reference Frame, BR12-23, Part 2)
 
   3.4 Complete WF/PC-2 5370 (HST Medium-Deep Survey: Cycle 4 High Galactic
       Latitude)
 
   3.5 Complete WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 1)
 
   3.6 Complete WF/PC-2 5397 (Determination of the Extragalactic Distance
       Scale. Cycle 4 High)
 
   3.7 Complete WF/PC-2 5612 (SMOV WF/PC-2 Decontamination)
 
   3.8 Complete GHRS/1 5278 (GHRS N1 and G140L Sensitivity Calibrations:
       Cycle 4 )
 
   3.9 Complete Three Sets of  WF/PC-2 5476 (Continuum Snapshots of 3CR
       Radio Galaxies)
 
   3.10 Complete Three sets of WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration:
       Earthflats, Large Set)
 
   3.11 Complete FOS/RD 5530 (FOS Location of Spectra and Aperture)
 
   3.12 Complete FOC/96 5140 (Observations of the Narrow Line Regions in
       Nearby Seyfert Galaxies)
 
   3.13 Complete WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
   3.14 Complete WF/PC-2 5090 (Large Area/ Multicolor Survey: Cycle 4)
 
   3.15 Complete Three Sets WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 2: Flats)
 
   3.16 Complete Two Sets of WF/PC-2 5415 (The Distance to the M-96 Galaxy
       Group: Cycle 4 Medium)
 
   3.17 Complete GHRS/2 5300 (Probing the Outer Galactic Halo: Cycle 4 
High)
 
   3.18 Complete GHRS/2 5506 (The Deuterium Abundance in Moderate Redshift
       QSO Systems)
 
   3.19 Complete FGS 5174 (Astrometric Companion Search: Cycle 4)
 
   3.20 Complete WF/PC-2 5091  (GTO High Latitude Parallel Program: Cycle 
4)
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       Nothing at this time.
 

 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1114
 
PERIOD COVERED:  0700 EST 04/08/94 - 0700 EST 04/11/94
 
Daily Status Report as of 101/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed WF/PC-2 5475 (A Snapshot Survey for Blue Stragglers in
       Magellanic Cluster Cores)
 
       The WF/PC-2 was used to make short exposure snapshot images of the
       blue straggler stars located in populous clusters NGC-419,
       NGC-1868, and NGC-1847. A populous cluster is the Magellanic Cloud
       equivalent of a galactic globular cluster. The observations were
       made with two different color filters. The intent is to find out if
       blue straggler stars exist within this cluster. For the first
       cluster two observations were received and displayed. There were
       some recenterings, but no other problems. The next two objects were
       observed during LOS, and the data remains on the science tape
       recorder. The data will be analyzed later. No anomalies were noted.
 
   1.2 Completed WF/PC-2 5562 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor 3: Darks)
 
       The WF/PC-2 was used to obtain a 30-minute long, dark exposure to
       provide ongoing calibration of the CCD dark current and to monitor
       and characterize the evolution of hot pixels. One image was received
       and displayed in the OSS. The image was reported to look okay.
 
   1.3 Completed FGS 5333 (Linking the HIPPARCOS to the Extragalactic
       Reference Frame, BR12-23, Part 2)
 
       The FGSs were used to obtain astrometric observations on several
       stars whose apparent positions lie near extragalactic objects.
       These stars will also be observed with the HIPPARCOS satellite. The
       intent is to tie the HIPPARCOS reference frame to the extragalactic
       frame. Five astrometric observations were monitored in real-time.
       Observations of the third object ended with a Stop Flag set, but
       the other four observations were successful.
 
   1.4 Completed WF/PC-2 5370 (HST Medium-Deep Survey: Cycle 4 High
       Galactic Latitude)
 
       The WF/PC-2 was used in parallel with the prime science observations
       to make high galactic latitude observations as part of a medium-deep
       sky survey. The main purpose of these observations is to study the
       evolution and structure of galaxies. Two observations were received
       and displayed. there was one recentering event, and lots of cosmic
       ray hits. Otherwise, there were no problems.
 
   1.5 Completed WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 1)
 
       The WF/PC-2 was used to make several internal bias, and K-Spot
       calibration observations to monitor the CCD camera electronics, the
       optical alignment, and for contamination. A total of ten images were
       taken. Ten observations were received and displayed. No problems
       were noted.
 
   1.6 Completed WF/PC-2 5397 (Determination of the Extragalactic Distance
       Scale. Cycle 4 High)
 
       The WF/PC-2 was used to make images of galaxy NGC-5457-FI to help
       establish the Hubble constant to an accuracy of better than 10% by
       measuring the periods of Cepheid variable stars within the galaxies.
       Five images were received and displayed. No problems were noted
       other than some recenterings during most of the exposures.
 
   1.7 Completed WF/PC-2 5612 (SMOV WF/PC-2 Decontamination)
 
       The WF/PC-2 was used to perform decontamination operations.
       Observations of standard  A+81D266, and K-Spot observations were
       also taken. A total of nine observations were monitored and
       displayed. The target star was reported to be saturated in the last
       two images. No other anomalies were noted.
 
   1.8 Completed GHRS/1 5278 (GHRS N1 and G140L Sensitivity Calibrations:
       Cycle 4 )
 
       The High Resolution Spectrograph (Side One) was used to make
       calibration observations of ultraviolet standard star BD28D4211 to
       determine if the N1 mirror may be used for target acquisitions and
       to re-establish the sensitivity calibration for the G140L grating.
       19 observations were monitored and displayed. The onboard Large
       Science Aperture (LSA) target acquisition was successful, and the
       confirmation map showed the target well centered. The onboard Small
       Science Aperture (SSA) target acquisition was also successful. No
       anomalies were noted.
 
   1.9 Completed WF/PC-2 5476 (Continuum Snapshots of 3CR Radio Galaxies)
 
       The WF/PC-2 was used to make snapshot images of radio galaxies
       3C287.1 and 3C238.0 as part of a continuum survey and to study the
       galaxies' morphology. Two images were received and displayed. Both
       were reported to look okay.
 
   1.10 Completed Three sets of WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration:
       Earthflats, Large Set)
 
       The WF/PC-2 was used to make a set of Earth flat calibration images
       using different filters in order to construct high quality flat
       fields of the OTA illumination pattern. A total of sixteen images
       were received and displayed. Four images were reported to be
       saturated, two were underexposed, and ten were okay.
 
   1.11 Completed FOS/RD 5530 (FOS Location of Spectra and Aperture)
 
       The Faint Object Spectrograph (Red Side) was used to make Y-base maps
       of the FOS detectors using internal lamps. The purpose is to
       determine the location of the spectra on the diodes. A total of nine
       observations were received and displayed. They all were reported to
       be okay.
 
   1.12 Completed FOC/96 5140 (Observations of the Narrow Line Regions in
       Nearby Seyfert Galaxies)
 
       The Faint Object Camera (f/96) was used to make observations at
       several different wavelengths of Seyfert galaxy MRK-79 which is
       located near the Cygnus A source. This is to study relations between
       the radio and optical emissions. The OSS monitored the observations,
       and assessed the data quality. Six images were received and
       displayed. They were reported to be probably satisfactory, though
       most were saturated in the center.
 
   1.13 Completed WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
       The WF/PC-2 was used to make an observation taken in parallel with
       the prime science observations. This is part of a survey to take
       pictures of a large number of fields within 30 degrees of the
       galactic plane. The intent is to determine the luminosity function
       of low mass stars and the mass density in the solar neighborhood.
       The image was received as scheduled, and it was reported to look
       okay.
 
   1.14 Completed WF/PC-2 5090 (Large Area/ Multicolor Survey: Cycle 4)
 
       The WF/PC-2 was used to make deep exposure images of field #1415 as
       part of a large area, high galactic latitude, multicolor sky survey
       to learn more about the distribution of galaxies, their morphology,
       distribution in magnitude and redshift, and evolution of galactic
       luminosity, function, and colors. Two images were received and
       displayed. Except for some recenterings, no other anomalies were
       noted.
 
   1.15 Completed Three Sets WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 2: Flats)
 
       The WF/PC-2 was used to make ultraviolet flat calibration images
       to monitor flat field stability and the stability of the
       analog-to-digital converters. Two observations were monitored by the
       OSS, and no anomalies were noted.
 
   1.16 Completed Two Sets of WF/PC-2 5415 (The Distance to the M-96 Galaxy
       Group: Cycle 4 Medium)
 
       The WF/PC-2 was used to make observations of Cepheid variable stars
       within the galaxy UGC-5889 which itself is located in the M-96
       galaxy cluster. This is to help determine the distance to this
       galactic group, and to improve the determination of the Hubble
       constant. Two observations were received and displayed. Except for
       some recenterings, no other problems were noted.
 
   1.17 Completed GHRS/2 5300 (Probing the Outer Galactic Halo: Cycle 4
       High)
 
       The High Resolution Spectrograph (Side Two) performed observations
       of AGN F5 as a probe to study the physical properties of the gas in
       the Outer Galactic Halo. The observations were made using grating
       G160M. Much of the data still remains on the science tape recorder,
       and will be analyzed later. Except for some recentering events, no
       anomalies were noted.
 
   1.18 Completed GHRS/2 5506 (The Deuterium Abundance in Moderate Redshift
       QSO Systems)
 
       The High Resolution Spectrograph (Side Two) was used to make
       observations of QSO 0454-220. This is to attempt to measure the
       deuterium to Hydrogen ratio in the spectrum of the highly
       red-shifted quasar. A wavelength calibration image was also made.
       The observations were executed as scheduled, no anomalies were
       noted.
 
   1.19 Completed FGS 5174 (Astrometric Companion Search: Cycle 4)
 
       FGS #3 was used to make astrometric observations of the possible
       binary dwarf star W922 to look for an astrometric, unseen, low mass
       companion. The OSS monitored the observations and assessed the data
       quality. No anomalies were noted.
 
   1.20 Completed WF/PC-2 5091  (GTO High Latitude Parallel Program: Cycle
       4)
 
       The WF/PC-2 was used in parallel with the prime science observations
       to make high galactic latitude observations greater than +/-30
       degrees. These are randomly chosen fields to sample very low
       luminosity stars in the solar galactic neighborhood, galactic halo
       objects, and distant galaxies. Two observations were executed
       parallel to the astrometry, and no anomalies were noted.
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions : 18
                                        Successful : 18
                          Scheduled Reacquisitions : 27
                                        Successful : 27
 
   2.2 FHST Updates:
 
                              Scheduled :43
                             Successful :43
 
   2.3 Significant HSTARs:
 
       Safemode entry at 101/0559Z. SA Profile Test failed.
 
       HST entered software sunpoint safemode on day 101 at 05:59:00 GMT.
       This occurred after the DF224 computer detected a profile error
       during a solar array maneuver from 68 degrees to the 117 degree
       position. Preliminary data indicates that the - solar array wing
       overshot its desired position at the end of the slew by at least 14
       degrees, enough to trigger the profile test. As a result of the
       safemode test failure, the DF224 turned off Solar Array Drive
       Electronics (SADE) 1, turned on SADE 2, and commanded +V3 software
       sunpoint mode. The solar arrays were then commanded to the 90 degree
       position by the DF224 under control of SADE 2, where they remain. No
       other problems have been detected and the HST is in a nominal
       software sunpoint configuration. Data analysis is underway, however
       all required data will not be available until late this morning due
       to ground station visibility for safemode tape recorder dumps.
 
   2.4 Operations Notes: None
 
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Three Sets of FOS/RD 5535 (Cycle 4 Internal Wavelength
       Calibration)
 
   3.2 Complete Three Sets of WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 2 Flats)
 
   3.3 Complete Two Sets of WF/PC-2 5475 (A Snapshot Survey for Blue
       Stragglers in Magellanic Cluster Cores)
 
   3.4 Complete FGS 5135 (Extragalactic Astrometry and Astrophysics FT0-11,
       Part 1 of 2)
 
   3.6 Complete WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
   3.7 Complete WF/PC-2 5402 (Multiple Arc Systems in X-Ray Selected
       Clusters: Cycle 4 Medium)
 
   3.8 Complete WF/PC-2 5476 (Continuum Snapshots of 3CR Radio Galaxies)
 
   3.9 Complete WF/PC-2 5612 (SMOV WF/PC-2 Decontamination )
 
   3.10 Complete WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 1)
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       Recovery of the spacecraft from Safe Mode, and the resumption of
       normal operations.
 
 

 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1115
 
PERIOD COVERED:  0700 EST 04/11/94 - 0700 EST 04/12/94
 
Daily Status Report as of 102/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
       The spacecraft entered software safemode at 101/0559Z. All
       observations after that time did not execute, and were mark as
       "failed".
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions : 0
                                        Successful : 0
                          Scheduled Reacquisitions : 0
                                        Successful : 0
 
   2.2 FHST Updates:
 
                              Scheduled :0
                             Successful :0
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes:
 
       The observatory remains in software sunpoint safemode. The anomaly
       investigation team continues to meet.
 
       The Gimbal Electronic Assemblies and the FHSTs were powered on
       immediately following communications recovery yesterday morning.
       The DCE was powered on at 1300Z.  The PSEA was reconfigured for SADE
       2 operations at 1405Z. FHST maps and tape recorder dumps are
       currently being managed by real-time commands.
 
       The tentative recovery schedule specifies that the health and safety
       SMS will begin this evening at 103/0000Z, and the first SMS from the
       STScI will begin execution tomorrow afternoon at 103/1900Z.
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
       The first SMS from the STScI will begin execution tomorrow afternoon
       at 103/1900Z.
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       Recovery of the spacecraft from software sunpoint safemode, and the
       resumption of normal science observations.
 

Article: 1114
From: [email protected]
Newsgroups: sci.astro.hubble
Subject: HST Status Report, 04/12 - 04/13
Date: Mon, 18 Apr 1994 14:58:29 GMT
Organization: Space Telescope Science Institute
 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1116
 
PERIOD COVERED:  0700 EST 04/12/94 - 0700 EST 04/13/94
 
Daily Status Report as of 103/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
       The spacecraft entered software safemode at 101/0559Z. All
       observations after that time did not execute, and were mark as
       "failed". 
 
2.0 FLIGHT OPERATIONS SUMMARY: 
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 0
                                        Successful : 0
                          Scheduled Reacquisitions : 0
                                        Successful : 0
 
   2.2 FHST Updates: 
 
                              Scheduled :0
                             Successful :0
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes: 
 
       The HST remains in software sunpoint safemode with all subsystems
       performing in a nominal fashion.  FHST maps and ETR dump are still
       being managed by real-time commands.  The HGA control laws were
       initialized at 102/1726Z.  Since then some problems with drops due
       to RFI have been encountered. 
 
       Implementation of the health and safety SMS was delayed because of
       problems experienced in the off-line testing of the SADE 1
       turn-on/SA slew test contingency cases.  The revised recovery
       schedule calls for the health and safety SMS to begin this evening
       at 104/0000Z. The Health and Safety SMS includes the FGS 1/2/3 spin
       test. The first SMS from the STScI is now scheduled to begin 24
       hours later, at 105/0000Z, and will run for three days. 
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD: 
 
       The first observational SMS from the STScI will begin execution  at
       105/0000Z. 
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS: 
 
       Recovery of the spacecraft from software sunpoint safemode, and the
       resumption of normal science observations. 
 

From: [email protected]
Newsgroups: sci.astro.hubble
Subject: HST Status Report, 04/14 - 04/15
Date: Mon, 18 Apr 1994 15:11:07 GMT
Organization: Space Telescope Science Institute
 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1118
 
PERIOD COVERED:  0700 EST 04/14/94 - 0700 EST 04/15/94
 
Daily Status Report as of 105/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
       The first observational SMS from the STScI began execution  at
       105/0000Z. 
 
   1.1 Completed XSAFE (Safemode Recovery of the HST Science Instruments: 
       FOC)
 
       The proposal was executed as scheduled, and no anomalies were noted. 
 
   1.2 Completed YSAFE (Safemode Recovery of the HST Science Instruments: 
       FOS)
 
       The proposal was executed as scheduled, and no anomalies were noted. 
 
   1.3 Completed WF/PC-2 5476 (Continuum Snapshots of the 3CR Radio 
       Galaxies)
 
       The WF/PC-2 was used to make snapshot images of radio galaxy 3C403.1
       as part of a continuum survey and to study the galaxy's morphology.
       The observations were executed as scheduled, and no anomalies were
       noted. The science observations remain on the science tape recorder,
       and will be analyzed later. 
 
   1.4 Completed WF/PC-2 5562 (WF/PC-2 Cycle 4: Internal Monitor 3: Darks)
 
       The WF/PC-2 was used to obtain several 30-minute long, dark exposures
       to provide ongoing calibration of the CCD dark current and to
       monitor and characterize the evolution of hot pixels. The
       observations were monitored in the OSS. The data remains on the
       science tape recorder, and will be analyzed later. 
 
   1.5 Completed GHRS/2 5398 (Eclipsing Mapping of the Chromospheric and 
       Transition Region Structure)
 
       The High Resolution Spectrograph was used to obtain high signal to
       noise ratio spectra of the eclipsing binary star HR2554 (aka,
       HD50337) which is a known Zeta Aurigae-Type binary star. This system
       consists of a dwarf star and a G6 giant star. The light from the
       dwarf will be used as a probe of the outer atmosphere of the giant
       star. The observations were executed as scheduled, and no anomalies
       were noted. 
 
2.0 FLIGHT OPERATIONS SUMMARY: 
 
    2.1 Guide Star Acquisitions: 
 
                            Scheduled Acquisitions : 3
                                        Successful : 3
                          Scheduled Reacquisitions : 3
                                        Successful : 3
 
   2.2 FHST Updates: 
 
                              Scheduled :10
                             Successful :10
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes: 
 
       The recovery from software sunpoint safemode was completed with the
       successful transition to normal science operations at 105/0000Z.
       There were no reported problems.  All HST susbsystems are performing
       nominally. 
 
       During the day yesterday while operating out of the health and safety
       SMS, the FGS spin test was conducted.  All real-time indications are
       that the test went well for each FGS, although much of data
       collected has not yet been fully analyzed. 
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD: 
 
   3.1 Complete WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal 
       Monitor. 1)
 
   3.2 Complete Two Sets of WF/PC-2 5415 (The Distance to the M-96 Galaxy 
       Group: Cycle 4 Medium)
 
   3.3 Complete Six Sets of WF/PC-2 5476 (Continuum Snapshots of 3CR Radio 
       Galaxies)
 
   3.4 Complete GHRS/2 5443 (A Study of Galactic Gas-Phase Abundance 
       Gradients: Cycle 4 High)
 
   3.5 Complete WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats. 
       Large Set)
 
   3.6 Complete Two Sets of WF/PC-2 5562 (WF/PC-2 4 Calibration: Internal 
       Monitor 3: Darks)
 
   3.7 Complete WF/PC-2 5351 (Properties of Interstellar Redshift Galactic 
       Disks Causing Damped Lyman Alpha)
 
   3.8 Complete WF/PC-2 5612 (SMOV WF/PC-2 Decontamination)
 
   3.9 Complete FGS 5054 (High Speed Astrometry: A Search for Planetary 
       Companions to Low-Mass Stars)
 
   3.10 Complete WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
   3.11 Complete WF/PC-2 5173 (WF/PC-2 Images of Ejecta From Eta Carine)
 
   3.12 Complete Two Sets of GHRS/2 5398 (Eclipse Mapping of the 
       Chromosphere and Transition Region Structure)
 
   3.13 Complete WF/PC-2 5397 (Determination of the Extragalactic Distance 
       Scale: Cycle 4 High)
 
   3.14 Complete FOC 5139 (A Search for Low-Mass Companions to Nearby 
       Astrometric Binaries)
 
   3.15 Complete WF/PC-2 5091 (GTO High Latitude Parallel Program: Cycle 4)
 
   3.16 Complete GHRS/2 5473 (The Interstellar Abundance of Krypton: Cycle 4 
       High)
 
   3.17 Complete WF/PC-2 5454 (Ellipticals with Kinamatically Distinct 
       Cores: Cycle 4 Medium)
 
   3.18 Complete S/C 5582 (FOC/48 Monthly Activation (Camera Section Only): 
       Cycle 4)
 
   3.19 Complete WF/PC-2 5098 (UV Spectra of Low Redshift QSOs: Cycle 4 
       Observations)
 
   3.20 Complete WF/PC-2 5324 (Globular Cluster Core Imaging)
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS: 
 
        Nothing at this time
 

From: [email protected]
Newsgroups: sci.astro.hubble
Subject: HST Status Report, 04/15 - 04/18
Date: Mon, 18 Apr 1994 17:36:09 GMT
Organization: Space Telescope Science Institute
 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1119
 
PERIOD COVERED:  0700 EST 04/15/94 - 0700 EST 04/18/94
 
Daily Status Report as of 108/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 1)
 
       The WF/PC-2 was used to make several internal bias calibration
       observations to monitor the CCD camera electronics, the optical
       alignment, and for contamination. A total of ten images were
       received and displayed. The fifth observation showed a bias jump,
       otherwise there was no problems.
 
   1.2 Completed Two Sets of WF/PC-2 5415 (The Distance to the M-96 Galaxy
       Group: Cycle 4 Medium)
 
       The WF/PC-2 was used to make observations of Cepheid variable stars
       within the galaxies UGC-5889 and NGC-3368 which are located in the
       M-96 galaxy cluster. This is to help determine the distance to this
       galactic group, and to improve the determination of the Hubble
       constant. Two observations were received and displayed in the first
       set. The first observation showed a 35 second recentering event, and
       the second observation had a 138 second recentering event in three
       second bursts. No problems were seen with the second set of images.
 
   1.3 Completed Six Sets of WF/PC-2 5476 (Continuum Snapshots of 3CR Radio
       Galaxies)
 
       The WF/PC-2 was used to make snapshot images of radio galaxy 3C200.0
       as part of a continuum survey and to study the galaxy's morphology.
       Three images were received and displayed. All three were reported to
       look okay.
 
   1.4 Completed GHRS/2 5443 (A Study of Galactic Gas-Phase Abundance
       Gradients: Cycle 4 High)
 
       The High Resolution Spectrograph was used to make observations of
       star HD177989 at three different wavelengths using the Echelle
       gratings to help measure galactic gas-phase abundance. Of particular
       interest are the ultraviolet interstellar absorption lines due to Si
       II, Zn II, Cr II, and Fe II. The observations were completed without
       apparent incident. The onboard 5X5 spiral target acquisition located
       the target in map six. There were several recentering events
       reported. Two observations were received and displayed, and it was
       reported to look okay.
 
   1.5 Completed WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats.
       Large Set)
 
       The WF/PC-2 was used to make a set of Earth flat calibration images
       using different filters in order to construct high quality flat
       fields of the OTA illumination pattern. A total of eight images were
       received and displayed. Four were underexposed, and four were
       saturated.
 
   1.6 Completed WF/PC-2 5562 (WF/PC-2 4 Calibration: Internal Monitor 3:
       Darks)
 
       The WF/PC-2 was used to obtain a 30-minute long, dark exposure
       to provide ongoing calibration of the CCD dark current and to
       monitor and characterize the evolution of hot pixels. The
       observation was dumped from the spacecraft; but due to TAC problems
       the data was not received. A Line Outage Recorder (LOR) playback was
       requested. The observation was received and displayed. It was
       reported to be nominal.
 
   1.7 Completed WF/PC-2 5351 (Properties of Interstellar Redshift Galactic
       Disks Causing Damped Lyman Alpha)
 
       The WF/PC-2 was used to make observations to study the diffuse
       material at intermediate redshifts that is identified by absorbing
       Lyman-Alpha spectrum from quasar 3C196.0. The observations were
       executed as scheduled, and no anomalies were noted.
 
   1.8 Completed WF/PC-2 5612 (SMOV WF/PC-2 Decontamination)
 
       The WF/PC-2 was used to perform decontamination operations.
       Observations of standard  A+81D266, and K-Spot observations were
       also taken. The OSS monitored the observations, and assessed the
       data quality. No anomalies were noted.
 
   1.9 Completed FGS 5054 (High Speed Astrometry: A Search for Planetary
       Companions to Low-Mass Stars)
 
       The  Fine Guidance Sensors were used to make observations of the
       position of the star Proxima Centauri to determine the presence of a
       Jupiter sized planet in orbit about the target star. The OSS
       monitored the observations and assessed the data quality. No
       problems were reported.
 
   1.10 Completed WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
       The WF/PC-2 was used to make observations taken in parallel with the
       prime science observations. This is part of a survey to take
       pictures of a large number of fields within 30 degrees of the
       galactic plane. The intent is to determine the luminosity function
       of low mass stars and the mass density in the solar neighborhood.
       The observations were executed as scheduled, and no anomalies were
       reported.
 
   1.11 Completed WF/PC-2 5173 (WF/PC-2 Images of Ejecta From Eta Carina)
 
       The WF/PC-2 was used to make observations of the Eta-Carnea nebula
       to study its morphology and the dynamics of the stellar ejecta. Six
       observations were received and displayed. They were reported to be
       nominal.
 
   1.12 Completed Two Sets of GHRS/2 5398 (Eclipse Mapping of the
       Chromosphere and Transition Region Structure)
 
       The High Resolution Spectrograph was used to obtain high signal to
       noise ratio spectra of the eclipsing binary star HR2554 (aka,
       HD50337) which is a known Zeta Aurigae-Type binary star. This system
       consists of a dwarf star and a G6 giant star. The light from the
       dwarf will be used as a probe of the outer atmosphere of the giant
       star. The first set of observations were executed in fine lock
       without apparent problems. However, the second set of observations
       were missing one observation. One observations appeared to run too
       long, and ran over into the time of the next observation. An HSTAR
       was written for the missing observation. Several recentering events
       were also reported.
 
   1.13 Completed WF/PC-2 5397 (Determination of the Extragalactic Distance
       Scale: Cycle 4 High)
 
       The WF/PC-2 was used to make images of galaxy NGC-5457-FL to help
       establish the Hubble constant to an accuracy of better than 10% by
       measuring the periods of Cepheid variable stars within the galaxy.
       One image was received and displayed. It was reported to have had a
       total of 17 recentering events, for a total of 81 seconds. No other
       problems were noted.
 
   1.14 Completed FOC 5139 (A Search for Low-Mass Companions to Nearby
       Astrometric Binaries)
 
       The Faint Object Camera (f/96) was used to to search for faint
       companions near the astrometric binary star GL866A. Two FOC images
       were received and displayed. It was reported that there appeared to
       have been an error in the stars coordinates.
 
   1.15 Completed WF/PC-2 5091 (GTO High Latitude Parallel Program: Cycle 4)
 
       The WF/PC-2 was used in parallel with the prime science observations
       to make high galactic latitude observations greater than +/-30
       degrees. These are randomly chosen fields to sample very low
       luminosity stars in the solar galactic neighborhood, galactic halo
       objects, and distant galaxies. Two images were received and
       displayed. They both were reported to be nominal.
 
   1.16 Completed GHRS/2 5473 (The Interstellar Abundance of Krypton: Cycle
       4 High)
 
       The High Resolution Spectrograph was used to make observations of
       the star Kappa Orionis which is an O/B class star to study the
       abundance of Krypton to provide information about stellar
       nucleosynthesis and stellar evolution. Two observations were
       received and displayed. No anomalies were noted.
 
   1.17 Completed WF/PC-2 5454 (Ellipticals with Kinamatically Distinct
       Cores: Cycle 4 Medium)
 
       The WF/PC-2 was used to make observations of the small elliptical
       galaxy NGC-1700 which contains a massive core which is kinamatically
       distinct from the rest of the galaxy. The observations were executed
       as scheduled, and no anomalies were noted.
 
   1.18 Completed S/C 5582 (FOC/48 Monthly Activation (Camera Section
       Only): Cycle 4)
 
        This proposal was executed as scheduled, and no anomalies were
        noted.
 
   1.19 Completed WF/PC-2 5098 (UV Spectra of Low Redshift QSOs: Cycle 4
       Observations)
 
       The WF/PC-2 was used to make two ultraviolet images of the Low-Z
       quasi-stellar object 3C286 to obtain images and spectra of the
       surrounding galaxy. The observations were monitored by the OSS, and
       the data quality was assessed. No anomalies were noted.
 
   1.20 Completed WF/PC-2 5324 (Globular Cluster Core Imaging)
 
       The WF/PC-2 was used to make observations of the center of globular
       cluster NGC-6624 to try and detect the flatting of the density
       profile which could result from binary heating and core
       oscillations. The observations were executed as scheduled, and no
       anomalies were noted.
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions : 28
                                        Successful : 28
                          Scheduled Reacquisitions : 22
                                        Successful : 22
 
   2.2 FHST Updates:
 
                              Scheduled :46
                             Successful :46
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes:
 
       There were no significant reported problems in any HST subsystem.
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Two Sets of WF/PC-2 5562 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 3: Darks)
 
   3.2 Complete WF/PC-2 5623 (SINS: The Supernova Intensive Study Target of
       Opportunity: Cycle 4)
 
   3.3 Complete GHRS/2 5357 (Cepheid Masses: Cycle 4 High)
 
   3.4 Complete WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats, Large
       Set)
 
   3.5 Complete FOC/96 5140 (Observations of the Narrow Line Regions in
       Nearby Seyfert Galaxies)
 
   3.6 Complete WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
   3.7 Complete WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 1)
 
   3.8 Complete GHRS/2 5398 (Eclipse Mapping of the Chromospheric and
       Transition Regions Structure)
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       Nothing at this time.
 

From: [email protected]
Newsgroups: sci.astro.hubble
Subject: HST Status Report, 04/18 - 04/19
Date: Tue, 19 Apr 1994 16:44:46 GMT
Organization: Space Telescope Science Institute
 
 
                            HUBBLE SPACE TELESCOPE
                               DAILY REPORT #1120
 
PERIOD COVERED:  0700 EST 04/18/94 - 0700 EST 04/19/94
 
Daily Status Report as of 109/1200Z.
 
1.0 ACTIVITIES SCHEDULED AND ACCOMPLISHED:
 
   1.1 Completed Two Sets of WF/PC-2 5562 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor. 3: Darks)
 
       The WF/PC-2 was used to obtain a 30-minute long, dark exposure to
       provide ongoing calibration of the CCD dark current and to monitor
       and characterize the evolution of hot pixels. The image was received
       and displayed in the OSS, and they were reported to look okay.
 
   1.2 Completed WF/PC-2 5623 (SINS: The Supernova Intensive Study Target
       of Opportunity: Cycle 4)
 
       The WF/PC-2 was used to make target-of-opportunity observations of
       supernova SN1994I. Four observations were received and displayed in
       the OSS. They all were reported to be nominal.
 
   1.3 Completed GHRS/2 5357 (Cepheid Masses: Cycle 4 High)
 
        The High Resolution Spectrograph (Side Two) was used to make
        ultraviolet spectral observations of binary Cepheid star HD91595 to
        determine its mass. Twelve observations were received and displayed
        in the OSS. They were reported to be satisfactory.
 
   1.4 Completed WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats,
       Large Set)
 
       The WF/PC-2 was used to make a set of Earth flat calibration images
       using different filters in order to construct high quality flat
       fields of the OTA illumination pattern. A total of eight images were
       received and displayed. Most of the observations were nominal. The
       last observation was written across a tape recorder track switch.
       Another observation was reported to be underexposed.
 
   1.5 Completed FOC/96 5140 (Observations of the Narrow Line Regions in
       Nearby Seyfert Galaxies)
 
       The Faint Object Camera (f/96) was used to make observations at
       several different wavelengths of a Seyfert galaxy which is located
       near the Cygnus A source. This is to study relations between the
       radio and optical emissions. The baseline guide star acquisition
       failed to acquire the star in fine lock. The guide star was acquired
       in coarse track, and the observations was reported to be degraded.
 
   1.6 Completed WF/PC-2 5092 (GTO Low Latitude Parallel Program: Cycle 4)
 
       The WF/PC-2 was used to make observations taken in parallel with the
       prime science observations. This is part of a survey to take
       pictures of a large number of fields within 30 degrees of the
       galactic plane. The intent is to determine the luminosity function
       of low mass stars and the mass density in the solar neighborhood.
       The baseline guide star acquisition failed to acquire the star in
       fine lock, and the observation was made in coarse track. The
       observation was reported to be degraded.
 
   1.7 Completed WF/PC-2 5560 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 1)
 
       The WF/PC-2 was used to make several internal bias, K-Spot, and flat
       calibration observations to monitor the CCD camera electronics, the
       optical alignment, and for contamination. The observations remain on
       the science tape recorder, and will be analyzed later. No anomalies
       were noted.
 
   1.8 Completed GHRS/2 5398 (Eclipse Mapping of the Chromospheric and
       Transition Regions Structure)
 
       The High Resolution Spectrograph was used to obtain high signal to
       noise ratio spectra of the eclipsing binary star HR2554 (aka,
       HD50337) which is a known Zeta Aurigae-Type binary star. This system
       consists of a dwarf star and a G6 giant star. The light from the
       dwarf will be used as a probe of the outer atmosphere of the giant
       star. The observations were executed as scheduled, and no anomalies
       were noted.
 
2.0 FLIGHT OPERATIONS SUMMARY:
 
    2.1 Guide Star Acquisitions:
 
                            Scheduled Acquisitions : 5
                                        Successful : 5
 
                                       At 108/2253Z One Fine Lock failed to
                                       Course Track. Subsequent acquisition
                                       at 109/0445Z was successful.
 
                          Scheduled Reacquisitions : 9
                                        Successful : 9
 
                                       Two Fine Locks failed to Course Tracks
 
   2.2 FHST Updates:
 
                              Scheduled :9
                             Successful :9
 
   2.3 Significant HSTARs: None
 
   2.4 Operations Notes:
 
       A quiet day was experienced as each HST subsystem reported nominal
       conditions.
 
3.0 ACTIVITIES SCHEDULED FOR NEXT REPORTING PERIOD:
 
   3.1 Complete Three Sets of WF/PC-2 5476 (Continuum Snapshot of 3CR Radio
       Galaxies)
 
   3.2 Complete FOS/RD 5623 (SINS: The Supernova Intensive Study Target of
       Opportunity: Cycle 4)
 
   3.3 Complete WF/PC-2 5475 (A Snapshot Survey for Blue Stragglers in
       Magellanic Cluster Cores)
 
   3.4 Complete WF/PC-2 5570 (WF/PC-2 Cycle 4 Calibration: Earthflats,
       Large Set)
 
   3.5 Complete WF/PC-2 5561 (WF/PC-2 Cycle 4 Calibration: Internal
       Monitor. 2: Flats)
 
   3.6 Complete GHRS/2 5398 (Eclipse Mapping of the Chromosphere and
       Transition Region Structure)
 
   3.7 Complete Two Sets of WF/PC-2 5562 (WF/PC-2 Cycle 4 Calibration:
       Internal Monitor 3: Darks)
 
   3.8 Complete WF/PC-2 5397 (Determination of the Extragalactic Distance
       Scale: Cycle 4 High)
 
4.0 ANOMALY STATUS:
 
   4.1 Significant New Anomalies: None
 
   4.2 Significant Unresolved Anomalies: None
 
5.0 SIGNIFICANT FORTHCOMING EVENTS:
 
       Nothing at this time.
 

From:	US4RMC::"ASTRO%[email protected]" "Astronomy Discussion 
        List" 13-MAY-1994 20:30:04.17
To:	Multiple recipients of list ASTRO <ASTRO%[email protected]>
CC:	
Subj:	Information on the STScI Listserver

Jim Caffey at Southwest Missouri State asked me about the various items
we distribute via the listserver here.  I figured I'd publish this latest
information to everybody.  (It's also available via gopher at stsci.edu.)

BTW, Jim, I can't seem to get a reply to your address to work!  Send
me a short note.

-Bill Gawne
 HST Science Planning and Scheduling

stsci/steis/listserver
03/03/93
                  Listserver for STEIS Files

   The Space Telescope Science Institute has augmented STEIS (the Space
Telescope Electronic Information Service) with listserver capabilities.
Users can subscribe to certain popular files, which will be e-mailed
automatically whenever they're updated. It is also possible to request
items from the archive of previous files. The list of available files
will expand with time to include other frequently accessed ascii files.
Please send any requests for additional files you would like to see made
available through listserver to [email protected].


    Files currently available for subsciption are:

             filename                       description
        long-range-plan         - lists observations for the coming year
        timeline                - detailed weekly schedule of observations
        hst-status              - daily activity/instrument status reports
        completed-observations  - list of all observations completed to date
        wfpc-psf-library        - point spread functions for wfpc
        wfpc-delta-flats        - delta flat field information for wfpc


To subscribe to a listserver file, send a message with a blank subject
line to [email protected] and the following text:

                subscribe  file name   Your Name

where file name is one of the above file names and Your Name
represents the user's full name. Your return email address is copied
from this message and added to the list of subscribers.  To
unsubscribe from a list, just replace subscribe with unsubscribe in
the above message.

 For a quick overview of commands, send a message with a blank
subject line to the same email address but with the word HELP as
the message. Listserver is a UNIX utility and is described in detail in
the  User Commands Manual. For further assistance contact Fred
Romelfanger ([email protected], phone: (410) 516-8641) or Pete
Reppert ([email protected], phone: (410) 338-4551).

Pete Reppert and Chris O'Dea
User Support Branch

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date:         Fri, 13 May 1994 16:32:37 -0500
% Reply-To: Astronomy Discussion List <ASTRO%[email protected]>
% Sender: Astronomy Discussion List <ASTRO%[email protected]>
% From: Bill Gawne <[email protected]>
% Subject:      Information on the STScI Listserver
% X-To:         [email protected]
% To: Multiple recipients of list ASTRO <ASTRO%[email protected]>

From:	VERGA::US4RMC::"[email protected]" "It's not easy having a good 
        time.....even smiling makes my face ache." 19-MAY-1994 15:55:06.97
To:	distribution:;@us4rmc.pko.dec.com 
CC:	
Subj:	Hubble Finds Mysterious Ring Structure Around Supernova 1987A

                                   	EMBARGOED UNTIL 11:00 A.M. EDT
CONTACT:  Ray Villard, STScI            	Thursday, May 19, 1994   
          (410) 338-4514

                              		PRESS RELEASE NO.: STScI-PR94-22 
          Dr. Christopher Burrows ESA/STScI
          (410) 338-4913

HUBBLE FINDS MYSTERIOUS RING STRUCTURE AROUND SUPERNOVA 1987A 

NASA's Hubble Space Telescope (HST) has obtained the best images
yet of a mysterious mirror- imaged pair of rings of glowing gas
that are encircling the site of the stellar explosion supernova 1987A.
  
One possibility is that the two rings might be "painted" by a
high-energy beam of radiation or particles, like a spinning
light- show laser beam tracing circles on a screen.

The source of the radiation might be a previously unknown stellar
remnant that is a binary companion to the star that exploded in
1987. Images taken by Hubble show a dim object in the position of
the suspected source of the celestial light show. 

"The Hubble images of the rings are quite spectacular  and
unexpected," says Dr. Chris Burrows of the European Space Agency
and the Space Telescope Science Institute in Baltimore, Maryland. 
Burrows used Hubble's Wide Field Planetary Camera 2 to image the
rings in February 1994.

The striking Hubble picture actually shows three rings.  The
smaller "center" ring of the trio was seen previously.  The
larger pair of outer rings were also seen in ground-based images,
but the interpretation was not possible until the higher
resolution Hubble observations.

Though all of the rings probably are inclined to our view (so
that they appear to intersect), they probably are in three
different planes.  The small  bright ring lies in a plane
containing the supernova; the two rings lie in front and behind it. 

To create the beams illuminating the outer rings, the remnant
would need to be a compact object such as a black hole or neutron
star with a nearby companion.  Material falling from the
companion onto the compact object would be heated and blasted
back into space along two narrow jets, along with a beam of
radiation.  As the compact object spins it might wobble or
precess about its axis, like a child's top winding down. The twin
beam would then trace out great circles like jets of water from a
spinning lawn sprinkler. 

If the rings are caused by a jet, however, the beams are
extremely narrow (collimated to within one degree). This leads
Burrows to conclude: "This is an unprecedented and bizarre
object.  We have never seen anything behave like this before."

The jet model explains why the rings appear to be mirror imaged,
and why they appear to be symmetrical about a point offset from
the center of the explosion. 

Burrows got the idea for the beam explanation when he noticed
that where a ring appears brighter, an equally bright region
appears on opposite ring.  By connecting lines between the
similar clumps on opposite rings Burrows found a common center. 
However, it is offset from the heart of the supernova ejecta. 
When Burrows did a detailed inspection of the HST image, he found
a dim object which may be the source of the beam at the predicted
location. The object is about 1/3 light-year from the center of
the supernova explosion. 

From previous HST observations and images at lower resolution
taken at ground-based observatories, astronomers had expected to
see an hourglass-shaped bubble being blown into space by the
supernova's progenitor star.  "The rings are probably on the
surface of the hourglass shape," says Burrows.
 
The hourglass was formed by a wind of slow-moving gas that was
ejected by the star when it was a red supergiant, and a much
faster wind of gas that followed during the subsequent blue
supergiant stage. The hourglass was produced by the fact that the
stellar wind from the red giant was denser in the equatorial plane 
of the star. When the star reached the blue supergiant stage, 
the faster winds tended to break out at the poles of the star. 

Energetic radiation from the supernova explosion illuminated the
dense gaseous material in the equatorial "waist" of the
hourglass, causing it to glow -- thus explaining the central
bright ring.  However, the two outer rings might be painted on
the surface of the hourglass by a very different process, by the
beams from the stellar remnant.

Further observations with HST will study any further changes that
might occur. In particular, if a remnant companion really exists,
it should collide with the supernova's expanding cloud of ejecta
in the mid 1990s.

The observations were led by Dr. Chris Burrows in collaboration
with the WFPC 2 Investigation Definition Team.  The supernova is
169,000 light years away, and lies in the dwarf galaxy called the
Large Magellanic Cloud, which can be seen from the southern hemisphere. 

                     *********************************

The Space Telescope Science Institute is operated by the Association
of Universities for Research in Astronomy, Inc. (AURA) for NASA, under
contract with the Goddard Space Flight Center, Greenbelt, MD.  The
Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA). 

PHOTO CAPTION:  STScI-PR94-22          FOR RELEASE:  Thursday, May 19, 1994 

HUBBLE FINDS MYSTERIOUS RING STRUCTURE AROUND SUPERNOVA 1987A  

This striking NASA Hubble Space Telescope picture shows three
rings of glowing gas encircling the site of supernova 1987A, a
star which exploded in February 1987.

Though all of the  rings appear inclined to our view (so that
they appear to intersect) they are probably in three different
planes.  The small  bright ring lies in a plane containing the
supernova, the two larger rings lie in front and behind it.

The rings are a surprise because astronomers expected to see,
instead, an hourglass shaped bubble of gas being blown into space
by the supernova's progenitor star (based on previous HST
observations, and images at lower resolution taken at
ground-based observatories). 

One possibility is that the two rings might be "painted" on the
invisible hourglass by a high-energy beam of radiation that is
sweeping across the gas, like a searchlight sweeping across
clouds. The source of the radiation might be a previously unknown
stellar remnant that is a binary companion to the star that
exploded in 1987.

The supernova is 169,000 light years away, and lies in the dwarf
galaxy called the Large Magellanic Cloud, which can be seen from
the southern hemisphere.

The image was taken in visible light (hyrdrogen-alpha emission),
with the Wide Field Planetary Camera 2, in February 1994.   

credit:   Dr. Christopher Burrows, ESA/STScI and NASA 

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Thu, 19 May 1994 15:41:23 -0500 (EST)
% Subject: Hubble Finds Mysterious Ring Structure Around Supernova 1987A

From:	VERGA::US4RMC::"[email protected]" "It's not easy having a good 
        time.....even smiling makes my face ache." 19-MAY-1994 15:55:22.74
To:	distribution:;@us4rmc.pko.dec.com 
CC:	
Subj:	HST Observes the Supernova in the Whirlpool Galaxy

                              		EMBARGOED UNTIL 11:00 A.M.  EDT
CONTACT:  Ray Villard, STScI                     Thursday, May 19, 1994
          (410) 338-4514
                              		PRESS RELEASE NO.: STScI-PR94-20
          
          Dr. Robert P. Kirshner, Harvard University (617) 495-7519

            HST OBSERVES THE SUPERNOVA IN THE WHIRLPOOL GALAXY 

NASA's Hubble Space Telescope has returned valuable new images of
supernova 1994I in the inner regions of the "Whirlpool Galaxy," M51,
located 20 million light-years away in the constellation Canes
Venatici.  The images were taken with the Wide Field and Planetary
Camera 2 (WFPC2). 

The supernova was discovered by amateur astronomers on April 2, 1994
and has been the target of investigations by astronomers using ground-
based optical and radio telescopes.  At its brightest, around April 10, 
the supernova was about 100 million times brighter than the Sun. 

Previous observations show that SN 1994I is a very unusual supernova,
called "Type Ic," for which very few examples have been studied carefully. 

Following initial observations with the International Ultraviolet
Explorer satellite, which demonstrated that the supernova could be
detected in the ultraviolet, a preplanned series of observations was
initiated by the international SINS (Supernova Intensive Survey) team,
headed by Dr. Robert P. Kirshner of Harvard-Smithsonian Center for
Astrophysics. 

The SINS group is using HST to study supernovae in the ultraviolet
shortly after they are discovered, and at optical wavelengths as they
become too faint to monitor from the ground. They hope to learn which
stars explode as supernovae, what chemical elements are ejected by the
eruption, and how to use these bright events as yardsticks for
measuring the size of the universe. 

For example, the Supernova 1987A, located in the nearby Large
Magellanic Cloud, has been studied by the SINS team since the launch
of the HST in 1990 and will continue to be a target of investigations.

A supernova is a violent stellar explosion that destroys a star, while
ejecting the products of nuclear burning into the gas between stars. 

Hubble Space Telescope has the unique capability of being able to
image and to measure the spectra of distant supernovae in ultraviolet
light.  As the M51 supernova ages, Hubble will see more deeply into
the interior of the exploded star.  This will allow astronomers to
probe the chemical composition of the debris and to learn more about
the type of star that exploded. Debris from supernova explosions play
a central role in increasing the heavy element abundance of galaxies.
The material that makes up the Sun, the Earth, and our bodies was once
inside stars that exploded long before the solar system formed about
five billion years ago. 

                     *********************************

The Space Telescope Science Institute is operated by the Association
of Universities for Research in Astronomy, Inc. (AURA) for NASA, under
contract with the Goddard Space Flight Center, Greenbelt, MD.  The
Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA). 

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Thu, 19 May 1994 15:36:38 -0500 (EST)
% Subject: HST Observes the Supernova in the Whirlpool Galaxy

From:	US4RMC::"[email protected]" "Peter Yee" 10-JUN-1994 01:30:54.00
To:	[email protected]
CC:	
Subj:	Hubble briefing on protoplanetary disks [NTE 94-40] (Forwarded)

Sarah Keegan
Headquarters, Washington, D.C.				June 9, 1994
(Phone:  202/358-1547)

Jim Elliott
Goddard Space Flight Center, Greenbelt. Md.
(Phone 301/286-6256)

NOTE TO EDITORS: N94-40

HUBBLE BRIEFING ON PROTOPLANETARY DISKS

	New Hubble Space Telescope (HST) pictures of protoplanetary
disks in a cluster of young stars will be the subjects of a media
briefing Monday, June 13, 1994, at 2:00 p.m. EDT in the NASA
Headquarters auditorium, 300 E Street, SW, Washington, D.C. 

	Presenting the images and his findings will be Dr. C. Robert
O'Dell, professor of astrophysics at Rice University in Houston. 
Moderator Dr. Stephen Maran, NASA's Goddard Space Flight Center, will
be joined by Dr. Anne Kinney, astronomer, Space Telescope Science
Institute, Baltimore, Md., and Dr. Suzan Edwards, professor of
astronomy at Smith College, in a discussion of the significance of
these findings. 

	Copies of the new HST images will be available at the
briefing.  Immediately before and after the briefing, there will be a
clean video feed of the graphics used in the program. 

	This event will be carried live on NASA Television, Spacenet 2, 
69 degrees west longitude, Transponder 5 (Channel 9), frequency 3880 MHz. 

Article: 60825
Newsgroups: sci.astro
From: [email protected] (Stupendous Man)
Subject: Whatever happened to Stratoscope?  The sad answer....
Sender: [email protected] (USENET News System)
Organization: Princeton University
Date: Thu, 9 Jun 1994 19:06:05 GMT
 
 Gerald Cecil writes about balloon-borne telescopes::
 
> This would followup on the Stratoscope balloon telescope that Spitzer,
> Schwarzschild, & Co. flew in the late 60's (a 60cm telescope
> that was diffraction limited, and mothballed after its 3rd[?] flight in 1970
> because of the imminent launch of HST!  Stupendous Man can get the details
> in Peyton Hall.) 
 
  I'm out of New Jersey at the moment, but if my recollections are
correct, the Stratoscope mirror -- which is actually about 1-meter in
diameter, I believe, and nearly diffraction-limited -- is languishing
in limbo. You see, it was placed into a telescope on the Princeton
campus, in the FitzRandolph Observatory, which is the big white dome
SE of the football stadium.  This building orginally housed a large
Clark refractor, but Princeton traded the refractor for a reflector
structure large enough to house the Stratoscope mirror. 
 
  Unfortunately, the observatory had an elevator floor (for use with
the looong tube of the old refractor), which, I am told, is now
defunct and out of repair.  As a result, the observatory is CLOSED,
and its use is forbidden to all (for fear of liability, I suppose). 
The department has no interest in the telescope: "What can you do with
a 36-inch telescope in New Jersey?"  I've tried to argue for any
number of projects, but ...  So, it looks like the mirror will
continue to sit, unused, until, um, Doomsday, I guess. 
 
  Sigh.  How depressing.
 
-- 
-----                                                    Michael Richmond
"This is the heart that broke my finger."    [email protected]
 

From:	US4RMC::"[email protected]" "We are the dream makers....and we are 
        the dreamers of the dreams. -- Willy Wonka" 13-JUN-1994 14:20:14.69
To:	distribution:;@us4rmc.pko.dec.com 
CC:	
Subj:	STScI-PR94-24

                                   EMBARGOED UNTIL:   2:00 P.M. EDT
CONTACT:  Ray Villard, STScI                  Monday, June 13, 1994
          (410) 338-4514
                                   PRESS RELEASE NO.: STScI-PR94-24
          
          Dr. C. Robert O'Dell
          (713) 527-8101 x3633

HUBBLE CONFIRMS ABUNDANCE OF PROTOPLANETARY DISKS AROUND NEWBORN STARS

NASA announced today that a Rice University astronomer using the
Hubble Space Telescope has uncovered the strongest evidence yet
that the process which may form planets is common in the Milky
Way galaxy, of which Earth is a part, and  the universe beyond.

Dr. C. Robert O'Dell said observations with the newly repaired
telescope clearly reveal that great disks of dust -- the raw
material for planet  formation -- are swirling around at least
half and probably many more of the stars in the Orion Nebula, a
region only 1,500 light-years from Earth where new stars are
being born.

O'Dell and a colleague, Zheng Wen, formerly of Rice and now at
the University  of Kentucky, surveyed 110 stars and found disks
around 56 of them.  Because  it is easier to detect the star than
the disk, it is likely that far more stars are being orbited by
protoplanetary material, O'Dell said. 

O'Dell first discovered these disks, which he dubbed "proplyds,"
in Hubble Space Telescope images taken in 1992.  However, the new
images bolster his theory by distinguishing clearly that the
objects are indeed pancake-shaped disks of dust, not shells of
dust as some astronomers have maintained.  HST clearly resolves a
young star at the center of each disk.  O'Dell has also been able
to measure at least a portion of the mass of a dust disk and
found  that the disk contains enough material to make an
Earth-like planet. 

The theory that the Earth and other planets of the solar system
were formed  out of just such a disk some 4.5 billion years ago
by the coalescing of matter caused by gravitational attraction is
widely accepted.  O'Dell said the disks in the Orion Nebula
presumably contain the same materials that constitute the planets
of Earth's solar system -- carbon, silicates, and other base
constituents.
 
The only confirmed planetary system to date, consists of three
earth-sized bodies orbiting a neutron star 1,000 light-years
away.  Since the neutron star is the burned-out remnant from a
stellar explosion, these planets might have formed at the end of
the star's life, and so, are not a good indicator of the
abundance of planetary systems like our own.

O'Dell's findings of an abundance of protoplanetary disks in a
cluster of  young stars reinforces the assumption that planetary
systems are common in the universe.

And because planets are necessary for life, as it is known on
Earth, to become established and flourish, the likelihood that
planets are common in the universe raises the likelihood of the
existence of life beyond Earth. 

The only place where life is known to exist is Earth.  Finding
life, or  fossils of life, elsewhere in our solar system -- the
major object of the exploration of Mars -- would be the first
evidence of life beyond Earth.  For life to arise independently
on two planets in the same solar system would mean  that life
likely is not accidental and is abundant in the universe. 

The Hubble images clearly distinguish the central star from the
disk and show that stars in Orion that are the mass of our Sun
and lower are likely to possess disks.  Stars hotter than our Sun
might destroy the dusty disks before they can agglomerate into
planets, according to O'Dell.
 
Hubble can see the disks because they are illuminated by the
hottest stars in the Orion Nebula, and some of them are seen in
silhouette against the bright nebula.  However, some of these
proplyds are bright enough to have been seen previously by
ground-based optical and radio telescopes as stars.  Their true
nature was not recognized until the Hubble observations.
   
One striking HST image shows a dark elliptical disk silhouetted
against the bright background of the Orion nebula.  "This object
represents the most direct evidence uncovered to date for
protoplanetary disks," says O'Dell. 

Hubble's resolution has allowed O'Dell to determine accurately
the mass of the outer rim of the disk.  It turns out to be at
least several times the mass of our Earth.  The entire disk is 53
billion miles across, or 7.5 times the diameter of our solar system.  
The central, reddish star is about one fifth the mass of our Sun.

The disks identified in the Hubble survey are a missing link in
the understanding of how planets like those in our planetary
system form.  Their abundance in a young star cluster shows that
the basic material of planets exists around a large fraction of
stars.  This reinforces the probability that many stars have
planetary systems.

Because the Orion star cluster is less than a million years of
age, there has not been enough time for planets to agglomerate
from the dust within the disks.  Many of the stars are still
contracting towards the mature status that they will then retain
for billions of years.  The most massive stars in the cluster
have already reached their adult stage of maximum hydrogen fuel
burning and their surfaces have become so hot that their
radiation heats up the gas left over after star formation.  This
is visible to observers with binoculars as the Orion nebula,
which is in the middle of the region known as the sword of Orion. 

THE GENESIS OF A SOLAR SYSTEM

Hubble Space Telescope's detailed images confirm more than a
century of speculation, conjecture, and theory about the genesis
of a solar system.

According to current theories, the dust contained within the
disks eventually agglomerates to make planets.  Hubble's images
provide direct evidence that dust surrounding a newborn star has
too much spin to be drawn into the collapsing star.  Instead, the
material spreads out into a broad, flattened disk.  

Before the Hubble discovery, remnant dust disks had been
confirmed around only four stars:  Beta Pictoris, Alpha Lyrae,
Alpha Piscis Austrini, and Epsilon Eridani.  They are a fraction
of the mass of the proplyds in Orion, and might be leftover
material from the planet formation process.  Less direct
detections of circumstellar material around stars in nearby star
forming regions have been made by radio and infrared telescopes. 

Unlike these previous observations, Hubble has observed newly
formed stars less than a million years old which are still
contracting out of primordial gas. 

Planets are considered a fundamental prerequisite for the
existence of life as we know it.  A planet provides a storehouse
of chemicals for manufacturing the complex molecules of biology,
gravitationally holds an atmosphere of gasses that are used by
life, and receives heat and light from the central star to power
photosynthesis and other chemical reactions required by life forms.  

O'Dell's Orion results will appear in the November 20 issue of
The Astrophysical Journal. 

                     *********************************

The Space Telescope Science Institute is operated by the Association
of Universities for Research in Astronomy, Inc. (AURA) for NASA, under
contract with the Goddard Space Flight Center, Greenbelt, MD.  The
Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA). 

PHOTO CAPTION  STScI-PR94-24a          FOR RELEASE: Monday, June 13, 1994  

                    HUBBLE PROBES THE GREAT ORION NEBULA
 
A NASA Hubble Space Telescope image of a region of the Great
Nebula in Orion.   
 
This is one of the nearest regions of very recent star formation
(300,000 years ago).  The nebula is a giant gas cloud illuminated by
the brightest of the young hot stars at the top of the picture.  Many
of the fainter young stars are surrounded by disks of dust and gas
that are slightly more than twice the diameter of the Solar System. 
 
The great plume of gas in the lower left in this picture is the
result of the ejection of material from a recently formed star.

The brightest portions are "hills" on the surface of the nebula, and
the long bright bar is where Earth observers look along a long "wall"
on a gaseous surface.  The diagonal length of the image is 1.6
light-years.  Red light depicts emission in Nitrogen; green is
Hydrogen; and blue is Oxygen. 

The Orion Nebula star-birth region is 1,500 light-years away, in
the direction of the constellation Orion the Hunter.
 
The image was taken on 29 December 1993 with the HST's Wide Field
and Planetary Camera  2.
 
 credit:  C.R. O'Dell/Rice University
          NASA
 
PHOTO CAPTION  STScI-PR94-24b          FOR RELEASE: Monday, June 13, 1994  

                      CLOSE-UP OF "PROPLYDS" IN ORION
 
A Hubble Space Telescope view of a small portion of the Orion Nebula
reveals five young stars.  Four of the stars are surrounded by gas and
dust trapped as the stars formed, but were left in orbit about the
star.  These are possibly protoplanetary disks, or "proplyds," that
might evolve on to agglomerate planets.  The proplyds which are
closest to the hottest stars of the parent star cluster are seen as
bright objects, while the object farthest from the hottest stars is
seen as a dark object. The field of view is only 0.14 light-years across. 
 
The Orion Nebula star-birth region is 1,500 light-years away, in the
direction of the constellation Orion the Hunter. 
 
The image was taken on 29 December 1993 with the HST's Wide Field and
Planetary Camera 2. 
 
 credit:  C.R. O'Dell/Rice University
          NASA

PHOTO CAPTION  STScI-PR94-24c          FOR RELEASE: Monday, June 13, 1994  

                    HUBBLE VIEW OF A PROTOPLANETARY DISK

A Hubble Space Telescope view of a very young star (between
300,000 and a million years of age) surrounded by material left
over from the star's formation.  The cool, reddish star is about
one fifth the mass of our Sun.  The dark disk, seen in silhouette
against the background of the Orion Nebula, is possibly a
protoplanetary disk from which planets will form.  The disk
contains at least seven times the material as our Earth.  The
disk is 56 billion miles across (90 billion kilometers), or 7.5
times the diameter of our Solar System.
 
The Orion Nebula starbirth region is 1,500 light-years away, in
the direction of the constellation Orion the Hunter.
 
The image was taken on 29 December 1993 with the HST's Wide Field
and Planetary Camera 2, WFPC2,  in PC mode.
 
 credit:  C.R. O'Dell/Rice University
          NASA

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Mon, 13 Jun 1994 13:57:56 -0500 (EST)
% From: "We are the dream makers....and we are the dreamers of the dreams. 
         -- Willy Wonka" <[email protected]
% Subject: STScI-PR94-24
% To: distribution:;@us4rmc.pko.dec.com (see end of body)
% Message-Id: <[email protected]>
% X-Vms-To: @STSCIPR.DIS
% X-Vms-Cc: MORRISSEY

From:	US4RMC::"[email protected]" "Peter Yee" 30-JUN-1994 19:39:49.24
To:	[email protected]
CC:	
Subj:	Hubble technology contributes to improved breast biopsies 
        [Release 94-107] (Forwarded)

Sarah Keegan
Headquarters, Washington D.C.                                 June 30, 1994
(Phone:  202/358-1547)

Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-6256)

RELEASE:  94-107

HUBBLE TECHNOLOGY CONTRIBUTES TO IMPROVED BREAST BIOPSIES

        A new, non-surgical and much less traumatic breast biopsy
technique, based on technology developed for NASA's Hubble Space
Telescope, is now saving women time, pain, scarring, radiation
exposure and money, according to NASA officials. 

        Radiologists predict that the new technique -- known as
stereotactic large-core needle biopsy -- will reduce national health
care costs by approximately $1 billion annually.  The new technique is
replacing surgical biopsy as the technique of choice, in many cases. 
Performed with a needle instead of a scalpel, it leaves a small
puncture wound rather than a large scar.  The patient is conscious
under local anesthesia compared to being unconscious in surgery. 

        The new technique involves a NASA-driven improvement to the
digital imaging technology known as a Charge Coupled Device or CCD. 
CCDs are high tech silicon chips which, unlike photographic film,
convert light directly into an electronic or digital image.  This
image can be manipulated and enhanced by computers.  For the last ten
years, CCDs have been almost routinely used to observe stars, galaxies, 
and other astronomical objects in visible and ultraviolet light. 

        In the breast imaging system, a special phosphor enables the
new CCD to convert X-rays to visible light, allowing the system to
"see" with X-ray vision.  The thinned and highly sensitive CCD --
which was not commercially available prior to Hubble's development --
is now leading the field of digital breast imaging technology,
according to medical specialists. 

        "The woman who has gone through a needle localization
procedure and formal surgical biopsy on a prior occasion and now comes
in to have the same thing done, but has it done as a stereotactic
biopsy, is about the most appreciative patient you can imagine,
because you've taken a long, drawn-out, anxiety-ridden and expensive
event and made it shorter, easier to schedule, more comfortable.  She
has no surgical wound," explained Dr. David Dershaw, Director of
Breast Imaging at Memorial Sloan-Kettering Cancer Center in New York. 
(His comments are in patient information materials of the LORAD Corp.,
Danbury, Conn., which produces breast imaging equipment.) 

        The technology breakthrough came when scientists at NASA's
Goddard Space Flight Center, Greenbelt, Md., developing the Space
Telescope Imaging Spectrograph (STIS) -- due to be installed on Hubble
in1997 -- realized that existing CCD technology could not meet the
instrument's demanding scientific requirements. 

        NASA contracted with Scientific Imaging Technologies, Inc.,
(SITe), of Beaverton, Ore., to develop a more sensitive CCD and lower
manufacturing costs.  After meeting NASA's rigorous scientific and
spaceflight requirements, the company then applied its new knowledge
to manufacturing CCDs for the digital spot mammography market.  The
result is a device that images suspicious breast tissue more clearly
and efficiently than is possible with conventional X-ray film screen
technology.  What made the transfer of knowledge possible was the
common imaging requirements of both astronomy and mammography:  high
resolution to see fine details, wide dynamic range to capture in a
single image structures spanning many levels of brightness, and low
light sensitivity to shorten exposures and reduce X-ray dosage. 

        SITe's CCD for digital breast imaging is virtually identical
to the CCD developed for Hubble, said William Stephens, Chief
Executive Officer of SITe.  Approximately 350 digital breast imaging
units containing SITe's thinned CCD already are in use, said Anne
Smith, Marketing and Communications Manager for the LORAD Corp., which
uses the STIS-like CCDs in its breast imaging equipment, and many more
are on order.  Currently, digital breast imaging is most often
associated with stereotactic biopsies, but by mid-1995, full digital
breast units should be available for routine mammographies. 

        In the new non-surgical technique, the CCD is part of a
digital camera system that "sees" the suspicious breast tissue.  A
needle extracts the tissue.  The patient lies face down with one
breast protruding through an opening in a specially designed table. 
The imaging device and needle are mounted under the table. 

        The radiologist locates the suspected abnormality with the
stereotactic X-ray imaging device by taking images of the suspected
mass from two different angles.  The computer finds the coordinates of
the abnormality based on those two images, and the radiologist
extracts a tiny sample of it with the needle.  The tiny puncture wound
is covered with a small bandage, and the patient can walk out of the
office minutes after the procedure and resume normal activities. 

        More than 500,000 American women undergo breast biopsies each
year.  While 80 percent of the suspicious masses are benign, this
cannot be determined without a biopsy.  The traditional surgical
technique involves running a guide wire into the breast to pinpoint
the mass, surgically following the wire and digging into the breast to
extract a tissue sample.  With the traditional surgical biopsy,
recuperation is about one week and involves a significant amount of
pain, suturing, and scarring, doctors say. 

        Although stereotactic location is also possible with X-ray
film technique, radiologists say the new digital imaging device
exposes patients to only half the radiation of the conventional X-ray
film method.  Unlike the X-ray film method, which radiates the entire
breast, digital imaging exposes only a small portion of the breast to
radiation. Also unlike X-ray film, which holds "frozen" pictures,
digital images can be computer-enhanced to sharpen details. No film or
plates must be processed, allowing patients to be evaluated in near
real time. 

        "In addition to exposing patients to about half the radiation,
digital breast imaging also approaches real time, cutting down
procedure time by one-half to one-third," said Dr. Dershaw.  "It's
more cost effective." 

        Studies show that the new procedure is just as effective as
traditional surgery.  While traditional surgery costs about $3,500,
core biopsy runs about $850.  Sampling suspicious tissue now can be
done in a radiologist's office. 

        The digital images, which are stored on computer disks, may be
downloaded instantly to distant experts via computer networks,
cellular signals or satellites, Stephens said.  The digital image
acquisition is almost foolproof, he explained, virtually eliminating
re-takes and additional radiation exposure. 

        "The image quality is much better because the signal-to- noise
ratio is better with CCDs," explained Dr. Hans Roehrig, Research
Professor of Radiology and Optical Science at the University of
Arizona.  "You don't get the granularity that you do with X-ray film,
which causes the signal-to-noise ratio of the film to be poor." 

        "Stereotactic biopsies also were done before the advent of the
thinned CCDs, but they took a long time,"  said Dr. Roehrig.  "First,
two X-ray pictures of the abnormality had to be taken.  The pictures
had to be developed in the darkroom, which takes about three minutes. 
Then, measurements had to be taken on the film images and run through
a computer in order to perform triangulation to determine the
coordinates [of the suspected abnormality]. The process of taking
pictures, developing the film and locating the coordinates of the
abnormal tissue mass typically takes about fifteen to twenty minutes,
and during this whole time, the patient -- still at the machine --
cannot move.  Now, in near real time, the entire process of locating
the mass can take as little as five minutes and is much more
comfortable for the patient." 

        The new biopsy technique, made possible by the CCDs developed
for Hubble Space Telescope, will spare millions of women pain, scars
and radiation exposure, will lead to much faster recuperation and will
save billions in health care costs. 

NOTE TO EDITORS:  Color and B&W images are available to news media
from NASA's Broadcast and Imaging Branch.  To obtain images, please
fax your request to the Branch at 202/358- 4333.  The photo numbers
for the color images are 94-HC-168 and 94-HC-169; and for the B&W
images, the numbers are 94-H- 180 and 94-H-183. 

From:	US4RMC::"[email protected]" "MAIL-11 Daemon" 30-JUN-1994 
To:	[email protected]
CC:	
Subj:	WFPC-II status 7/1/94

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

         WIDE FIELD AND PLANETARY CAMERA-II MISSION STATUS
                       Hubble Space Telescope
                            July 1, 1994

     The Jet Propulsion Laboratory's Wide Field and Planetary
Camera-II (WFPC-II), designed to correct for the flaw in the
Hubble Space Telescope's primary mirror, continues to perform
well and is being used to record the majority of images obtained
by the Hubble Space Telescope.

     The orbiting space telescope is currently concentrating on
key science programs that were made possible by the first
servicing mission last December to install the replacement
camera.  One of the primary programs being conducted is a precise
calibration of the cosmic distance scale from observations of
Cepheid variable stars in spiral galaxies belonging to the Virgo
cluster of galaxies.

     Other science targets include galaxies at extreme distances
in a deep-space survey; quasars and active galaxy nuclei; star
clusters and star-forming regions within the Milky Way galaxy and
its nearest neighboring galaxies, the Magellanic clouds.

     Scientists are also examining eruptive stars such as Eta
Carinae and supernova remnants such as the Crab nebula.  Io, a
moon of Jupiter having active volcanoes, has been imaged, as well
as the fragments of Comet Shoemaker-Levy 9, which will crash into
Jupiter's atmosphere beginning on July 16.

     All other Hubble Space Telescope and WFPC-II operations are
proceeding normally.  Instrument calibration is continuing as is
customary with any scientific instrument to assure that measuring
errors, however small, can be identified and corrected as
observational data is processed.  For example, there are slight
variations in the sensitivity and background signals from one
picture element (pixel) to another in WFPC-II's four charge-
coupled devices (CCDs) that record the images.  Background signal
variations in a small percentage of pixels are believed to result
from the impacts of charged particles from space. To minimize
such effects, the CCD temperatures were lowered by 10 degrees, to
minus 88 degrees Celsius, and are periodically warmed to room
temperature.  Such variations are routinely measured and compensated 
for in the data processing to remove their effects from the images.

     WFPC-II's science team expects that the Hubble Space
Telescope images will continue to be flawless, giving scientists
and the public the best views ever of astrophysical objects that
have been hidden from ground-based observations.

Article: 63375
Newsgroups: sci.astro
From: [email protected] (mary-frances  jagod)
Subject: HST detects promordial Helium
Sender: [email protected] (News System)
Organization: University of Chicago
Date: Thu, 7 Jul 1994 22:37:03 GMT
 
[Downloaded from NASA Spacelink]
 
Sarah Keegan
Headquarters, Washington, D.C.
July 7, 1994
 
Jim Elliott
Goddard Space Flight Center, Greenbelt, Md.
 
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
 
RELEASE:  94-109
 
HUBBLE DETECTS PRIMORDIAL HELIUM IN THE EARLY UNIVERSE
 
        An international team of astronomers has used the European Space
Agency's (ESA's) Faint Object Camera (FOC) on the Hubble Space Telescope (HST)
to confirm a critical prediction of the Big Bang cosmological theory -- that
the chemical element helium should be widespread in the early universe.
 
        The detection of this helium by HST may mark the discovery of a tenuous
plasma that fills the vast volumes of space between the galaxies -- the
long-sought after intergalactic medium.
 
        The new findings also shed light on the physical conditions that
existed in intergalactic space at a time when the universe was only a tenth of
its present age, and quasars and galaxies had only recently formed.
 
        The discovery follows from work done by a team of European astronomers,
led by ESA's project scientist for the FOC, Dr. Peter Jakobsen. The FOC was
used as a spectrograph to analyze the ultraviolet light received from a very
distant quasar.
 
        Reporting in the July 7, 1994, issue of the British science journal
Nature, the group describes how the helium was detected in the light of a
remote celestial body, a quasar, located in the constellation of Cetus at a
distance so great that its light has taken some 13 billion years, or 90% of the
age of the universe, to get to us.
 
        By showing that significant amounts of helium existed in the early
universe at a time when it was only a tenth as old as today, the discovery
reaffirms the explanation of the formation of the chemical elements in the
universe.  Hydrogen and helium were formed in the first three minutes after the
Big Bang by reactions between the primordial protons and neutrons.  The heavier
elements (carbon, oxygen, silicon, iron, etc.,) came only later through nuclear
reactions in the centers of stars.
 
        The Hubble Space Telescope is a project of international cooperation
between NASA and ESA.
 
        The scientific team responsible for this research includes Drs. Peter
Jakobsen of ESA/ESTEC, The Netherlands; Alec Boksenberg of the Royal Greenwich
Observatory, U.K.; Jean-Michel Deharveng of Laboratoire d'Astronomie Spatiale,
France; and Perry Greenfield, Robert Jedrzejewski and Francesco Paresce, all
working on the ESA FOC at the Space Telescope Science Institute, Baltimore, Md.

Article: 63380
From: DrDarkMatter
Newsgroups: sci.astro
Subject: Re: HST detects promordial Helium
Date: 7 Jul 1994 23:03:51 GMT
Organization: University of Oregon Network Services
Sender: [email protected] (A Service Organization)
 
Readers beware of this one.  Very difficult to show that this signal
is actually coming from a diffuse Intergalactic Medium as opposed to some
absorption cloud of material. Still its nice to confirm one of the
simplest predictions of big bang - that helium was created in an abundance
of 25% by mass in the first 15 minutes of the Universe's history

Article: 63384
From: [email protected] (Greg Hennessy)
Newsgroups: sci.astro
Subject: Re: HST detects promordial Helium
Date: Fri, 8 Jul 1994 00:23:36 GMT
Organization: None
 
In article <[email protected]>,  <DrDarkMatter> wrote:
>Readers beware of this one.  Very difficult to show that this signal
>is actually coming from a diffuse Intergalactic Medium as opposed to some
>absorption cloud of material. 
 
Since the Keck has also found a similar line (if I was at work I'd
give the reference, but it was in Nature about six weeks ago), how
many similar observations would it take for you to feel comfortable
this isn't a statistical conspiracy?
 
Greg Hennessy

Article: 63400
From: [email protected] (Ben Weiner)
Newsgroups: sci.astro
Subject: Re: HST detects promordial Helium
Date: 8 Jul 94 06:18:00 GMT
Organization: Rutgers Univ., New Brunswick, N.J.
 
[email protected] (Greg Hennessy) writes:
 
>In article <[email protected]>,  <DrDarkMatter> wrote:
>>Readers beware of this one.  Very difficult to show that this signal
>>is actually coming from a diffuse Intergalactic Medium as opposed to some
>>absorption cloud of material. 
 
>Since the Keck has also found a similar line (if I was at work I'd
>give the reference, but it was in Nature about six weeks ago), how
>many similar observations would it take for you to feel comfortable
>this isn't a statistical conspiracy?
 
The Hawaii group's detection is supposed to be a _deuterium_ line.
 
(Am I the only one who thinks it's weird when people say "the Keck did
this" or "HST did that"?  Perhaps for these observations it's OK since
the procedure is relatively standard and the aperture is really the
advance.)
 
Quasar spectra are positively riddled with hydrogen Lyman-alpha cloud 
absorption lines, anyway.  Take a look at a high-resolution spectrum
sometime.  That's why just one detection is not ironclad.

Article: 63422
From: [email protected] (Harry Ferguson)
Newsgroups: sci.astro
Subject: Re: HST detects promordial Helium
Date: 8 Jul 1994 15:12:14 GMT
Organization: Space Telescope Science Institute
 
This is a hard topic to try to explain in a newspaper or press release.
Yesterday the Baltimore Sun had an article on the results that was
completely incomprehensible. The press release is a bit better, but I
can see where the reporter might have gone wrong, as it doesn't give
much in the way of details.
 
The possibility of detecting an intergalactic medium (IGM) using the
light from distant quasars was recognized shortly after their
discovery. In 1965 Gunn and Peterson pointed out that smoothly
distributed primordial gas will produce a characteristic trough of
Lyman-alpha absorption due to neutral hydrogen extending from the
redshift of the quasar to shorter wavelengths. The depth of the trough
is a direct measure of the neutral hydrogen density in the IGM as a
function of redshift.  However, observations of quasars to date show no
such signature for a neutral IGM. There are many discrete absorption
lines in quasar spectra, but there is no continuous absorption that 
might have signaled the presence of a uniform IGM.
 
Therefore, either the IGM does not exist, or it is highly ionized.  The
test carried out by Jakobsen and collaborators  was to search for
absorption by the redshifted 304 Angstrom line of singly-ionized
helium. This could not be done from the ground, as even at reshifts 
>3 the line is still in the far ultraviolet.
 
The observations were made with the FOC objective prism, which gives a
low-resolution spectrum but allows for good background subtraction,
essential for this kind of observation. The reported optical depth is
~2.7 (if I recall correctly -- can't find the preprint at the moment).
Actually, this is something of a lower limit, as the quasar continuum
is not seen beneath the absorption trough.
 
While the result is very important, the HST observation does not by
itself tell us that there is a smooth IGM made up of primordial gas.
The spectral resolution and signal-to-noise ratio of the observations
are too low to tell us whether the helium absorption is continuous or
in discrete lines. Helium is presumably present in the known clouds
along the line of sight. The FOC observations provide information on the
shape of the ionizing radiation field if helium is present in these
clouds in its expected primordial abundance. It will take some detailed
modeling to decide whether some additional absorption due to a uniform
IGM is needed in to explain the depth of the observed trough.  Higher
resolution observations and observations along different lines of
sight are essential, but will be exceedingly hard to get.
 
The observations do not confirm that helium was formed in the big bang,
but are consistent with that explanation.
 
------------------------------------------------------------------------------
Harry Ferguson     Space Telescope Science Institute    Tel: (410) 338-5098
Internet:  	   [email protected]                   Fax: (410) 338-5090
------------------------------------------------------------------------------

From:	US4RMC::"[email protected]" "Andrew Yee, Science North"  
        1-AUG-1994 04:13:48.99
To:	[email protected]
CC:	
Subj:	High resolution HST images of Pluto and Charon

European Southern Observatory
Information and Photographic Service
Garching, Germany					18 May 1994

PRESS RELEASE: For immediate release
PR 09/94

AT THE EDGE OF THE SOLAR SYSTEM: HIGH RESOLUTION HST IMAGES OF PLUTO
AND CHARON 

The remote planet Pluto and its moon Charon orbit the Sun at a mean
distance of almost 6,000 million kilometres, or nearly fourty times
farther out than the Earth.  During a recent investigation by an
international group of astronomers (1), the best picture ever of Pluto
and Charon was secured with the European Space Agency's Faint Object
Camera at the Hubble Space Telescope (HST).  It shows the two objects
as individual disks, and it is likely that further image enhancement
will allow us to see surface features on Pluto. 

A very special pair of celestial objects

Almost all the known facts about these two bodies show that they are
quite unusual: Pluto's orbit around the Sun is much more elongated and
more inclined to the main plane of the Solar System than that of any
other major planet; Charon's orbit around Pluto is nearly
perpendicular to the plane; their mutual distance is amazingly small
when compared to their size; Charon is half the size of Pluto and the
ratio of their masses is much closer to unity than is the case for all
other planets and their moons.  Moreover, both are small and solid
bodies, in contrast to the other large and gaseous planets in the
outer Solar System. 

We do not know why this is so.  But there is another important aspect
which makes Pluto and Charon even more interesting: at this very large
distance from the Sun, any evolutionary changes happen very slowly. 
It is therefore likely that Pluto and Charon hold important clues to
the conditions that prevailed in the early Solar System and thus to
the origin and the evolution of the Solar System as a whole. 

Long and difficult analysis ahead

The present image shows that the overall quality of the new data
obtained with the ESA Faint Object Camera on the refurbished Hubble
Space Telescope is extremely good.  However, such an image represents
only the first step of a subsequent, detailed analysis with the ultimate 
goal of determining the physical properties of the two bodies, first of 
all their composition, surface structure, and possible atmospheres. 

The analysis of data from a facility as complex as the Hubble Space
Telescope is very demanding, and involves experts in many different
fields: planetary astronomy, instrument technology, numerical image
restoration, and spacecraft engineering.  It is therefore not surprising 
that this investigation is expected to last a long time yet. 

However, while still in its preliminary stages, it already now appears
to indicate the presence of areas of different reflectivity on the
surface of Pluto.  By a comparison of HST images obtained at two
different wavelengths (i.e. in ultraviolet and visual light), the team
members hope that it will become possible to construct rough maps of
the planetary surface and perhaps also to answer the long-standing
question of whether or not there is an atmosphere around Pluto. 

(1)  This investigation is carried out at the Space Telescope European
Coordinating Facility, which is located at the European Southern
Observatory as part of a collaboration with the European Space Agency,
and also involves other institutes in Europe and the U.S.A.  The team
of astronomers is headed by Rudolf Albrecht (ST-ECF), and includes
Hans- Martin Adorf and Richard Hook (ST-ECF), Alessandra Gemmo and
Olivier Hainaut (ESO), Cesare Barbieri and Gabriele Corrain
(Osservatorio Astronomico di Padova, Italy), Chris Blades, Perry
Greenfield and William Sparks (Space Telescope Science Institute,
Baltimore, Maryland, U.S.A.) and David Tholen (Institute for
Astronomy, University of Hawaii, U.S.A.) 

From:	US4RMC::"[email protected]" "MAIL-11 Daemon"  5-AUG-1994 
To:	[email protected]
CC:	
Subj:	WFPC-2 status 8/5/94

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

        WIDE FIELD AND PLANETARY CAMERA-2 MISSION STATUS
                    Hubble Space Telescope
                        August 5, 1994

     The Jet Propulsion Laboratory's Wide Field and Planetary Camera-2
-- the primary camera onboard NASA's Hubble Space Telescope -- is
continuing to take vivid images of distant stars, galaxies and the
planets of the solar system. 

     For the last month, the majority of Hubble's time has been
devoted to observations of the Comet Shoemaker-Levy 9 collisions in
mid-July, although other unrelated celestial targets were interleaved
into the observing schedule.  The Wide Field and Planetary Camera-2
was used to take approximately 500 images of the collisions between
July 15 and 26.  Nearly 100 images also were taken of the comet
fragments before they crashed to help scientists determine the
fragment orbits, sizes and any evidence of fragment disintegration. 
Jupiter is currently about 780 million kilometers (480 million miles)
from Hubble's orbit around Earth. 

     Observations will continue using the Wide Field and Planetary
Camera-2 through the end of August, while debris continues to pummel
the planet. This showering of comet debris will occur on the planet's
near side as viewed from Earth.  The collisions will occur at a
decreasing pace both in terms of impact frequency and characteristic
size of the individual particles. 

     As the events subside, astronomers will be interested in
observing changes in the characteristics of the impact sites.  The
impact features appear to be evolving on time scales of days as the
dark cloud sites move and become distorted by Jupiter's winds. 
Because these dark impact regions are at higher altitudes than the
regular Jovian cloud decks, tracking the spots will provide an
opportunity to measure the speed and direction of winds in Jupiter's
upper atmosphere. 

     The Wide Field and Planetary Camera-2 is taking advantage of its
ultraviolet capability -- not available from Earth-based telescopes --
to image the best full-disc ultraviolet photographs ever taken of
Jupiter.  Ultraviolet light is quickly absorbed by the planet's
atmosphere so it does not penetrate very far.  As a result,
astronomers see only the highest part of the atmosphere, where the
comet activity is most prevalent, in ultraviolet light. This explains
why familiar features such as Jupiter's Great Red Spot and different
colored cloud stripes appear washed out in ultraviolet images. 

                          #####

From:	US1RMC::"[email protected]" "Andrew Yee, Science North"  
        1-SEP-1994 03:53:22.67
To:	[email protected]
CC:	
Subj:	EURECA & HST solar arrays back at ESA/ESTEC after long
        journeys in space 

European Space Agency
Press Information Note No. 18-94
Paris, France					7 July 1994

EURECA AND HUBBLE SPACE TELESCOPE SOLAR ARRAYS BACK AT ESA/ESTEC AFTER
LONG JOURNEYS IN SPACE -- INITIAL OBSERVATIONS AND FINDINGS 

For more than 25 years European solar arrays have been developed, 
manufactured and used as power generators in space for the vast 
majority of Earth-orbiting satellites.  Until 1993 no solar array or major 
solar array parts had ever been returned to Earth after mission 
completion and apart from indirect telemetry data there was no direct 
information on the appearance and the durability of the complex and 
delicate solar arrays with their very large unprotected and electrically 
active surface after long term exposure to the hostile space environment.

This situation has changed completely since the two largest ESA solar 
arrays ever built have been successfully retrieved from space by 
successful Shuttle missions:

*  EURECA with its 5kW rigid panel array returned in August '93, after 11 
   months in a 500 km orbit.

*  The first servicing mission to the Hubble Space Telescope (HST) with 
   its 4.8kW flexible double-roll-out solar generator was carried out in 
   December '93, after almost 4 years in a 600 km orbit and one of the 2 
   solar array wings was brought back to Earth.

Both solar generators are currently being evaluated in the framework of 
Post-Flight Investigation Programme of ESA at the European Space 
Technology Center (ESTEC) in Noordwijk, the Netherlands, through 
investigations of the solar arrays subsystems and all major assemblies, 
mechanisms and components.  The two arrays represent two main 
conceptual families of deployable solar arrays, i.e. advanced carbon-
fibre face skin rigid panel and double-roll-out flexible blankets.  
Therefore, the mechanisms and structural elements used in the two 
arrays are basically different and not directly comparable whereas the 
electrically active solar cell panel surfaces are quite similar thus 
allowing comparative analyses.

Initial inspections and surveys have meanwhile been carried out at the 
manufacturer's premises (EURECA solar array at Fokker (the 
Netherlands) and HST array at British Aerospace (Great Britain)) where 
the arrays had been deployed for the first time after retrieval.  Mulitple 
deployments and retractions of both arrays went flawless and precisely 
as specified indicating excellent survivability of the associated 
mechanisms.  A visible change on the HST blankets is the darkening on 
some peripheral surfaces of synthetic materials (as expected from 
laboratory pre-tests).  Numerous small micrometeorite/debris impact 
craters ranging from a maximum of several mm diameter down to 
submillimeter size are visible from close-by in the solar cell area of both 
arrays.  672 impacts with a diameter of 1.2 mm or more were counted on 
the solar cell side of the HST array blankets and several particles 
penetrated in multilayer blankets.  However, this did not cause any loss 
of function or measurable electrical performance degradation of the 
monocrystalline silicon solar cells on either of the solar arrays.

In the solar cell area of one of the EURECA panels a pronounced burn 
mark is visible indicating plasma arcing and temperatures above 2000 
degrees centigrade for a short while during the mission.  The cause for 
this singular event is not known and subject of further investigations.  
Contrary to this unexplained anomaly, the investigations provided a good 
understanding of the fatigue damage mechanism of the flat silver wires 
on the EURECA panels as a consequence of the extended thermal 
cycling between -100 and + 90 degrees C in the Sun/eclipse transients 
which occur every 90 minutes.

The solar cell areas of the HST blankets and of the EURECA panels (with 
the exception of the singular burn mark mentioned above) appear "like 
new" and the solar cells degraded somewhat less than expected from the 
assumed worst case predictions thus confirming their excellent long-life 
operation potential in space.

The detailed investigations are expected to provide valuable information 
on the solar array environmental interactions.  The main environmental 
parameters in the associated orbits are thermal cycling due to thousands 
of sunlight/eclipse transients, atomic oxygen, high energy elementary 
particle radiation, UV radiation, low-Earth-orbit plasma and 
micrometeorites and space debris.  Exact knowledge of their effect on the 
solar array mechanisms, surfaces and components will lead to significant 
design improvements for the benefit of future space missions.

Already at this early stage of the post-flight investigations it is evident 
that the arrays withstood the large number of micrometeorites and debris 
impacts without measurable power loss.

This confirms the excellent survivability of solar cells in a very hostile 
environment which is quite extraordinary if one considers the clearly 
visible deep impact craters on one side and the delicate semiconductor 
structure of the solar cells on the other side.

From:	US1RMC::"[email protected]" 21-SEP-1994 13:32:49.08
To:	distribution:;@us1rmc.bb.dec.com (see end of body)
CC:	
Subj:	HST UNCOVERS HIDDEN QUASAR IN NEARBY GALAXY

CONTACT:  Ray Villard, STScI       EMBARGOED UNTIL: 6:00 P.M. EDT 
          (410) 338-4514       Wednesday, September 21, 1994
          
PRESS RELEASE NO.: STScI-PR94-42
          Dr. Anne Kinney, STScI
          (410) 338-4831

            HUBBLE UNCOVERS A HIDDEN QUASAR IN A NEARBY GALAXY

Astronomers using NASA's Hubble Space Telescope (HST) have found, to
their surprise, that a relatively nearby galaxy harbors a powerful
quasar.  This active galaxy, known as Cygnus A, is the second strongest
radio source in Earth's sky. 

Because most quasars are billions of light-years away, it is a
surprise to find one virtually in our own cosmic back yard -- at a
relatively close distance of 600 million light-years.  This discovery
by Hubble also means that astronomers now have a close-up example of a
quasar to study in detail. 

"I was stunned when we realized we had a quasar; it was a total
surprise," say Dr. Anne Kinney of the Space Telescope Science
Institute, Baltimore, Md. She emphasizes that this unexpected result
suggests that all powerful radio galaxies might harbor quasars that
are hidden from view. 

The observations were made by Robert Antonucci and Todd Hurt of the
University of California at Santa Barbara, and Kinney.  Their results
appear in the September 22 issue of Nature. 

Quasars (Quasi-Stellar Radio Sources) are compact objects that look
like pinpoints of light (like stars) in ground-based telescopes, but
are actually hundreds of times brighter than entire ordinary galaxies
like our Milky Way. There is increasing evidence that quasars dwell in
the core of remote galaxies, and are powered by a supermassive black
hole devouring dust, gas, and stars from the host galaxy.  Most
quasars existed billions of years ago in the early universe, and, so,
it's unusual to find one in our own epoch. 

Though Cygnus A is categorized as an elliptical galaxy, it has an
unusual peanut-shape due to a dark band of dust encircling the
enigmatic nucleus. The Hubble astronomers could only peek into the
core by taking advantage of a natural "periscope effect."  Dust
outside of the nucleus acts like a mirror to reflect the shorter
wavelengths or, blue component of the light, toward Earth. 

The astronomers used the ultraviolet sensitivity of the Faint Object
Spectrograph to look for the spectral signature of extremely hot,
supermassive stars hidden in the nucleus.  Such stars are theorized as
one possible explanation for Cygnus A's powerful optical emissions. 

Instead, the resulting ultraviolet spectrum was so unusual that
astronomers puzzled over the data for three months before reaching
their startling conclusion.  After much analysis, they realized it was
in part composed of the typical spectrum of a quasar.  Such a spectrum
possesses broad emission lines that indicate that gas in the nucleus
is swirling at high speeds. "One caveat is that the broad emission
line could possibly be many narrow emission lines blended together,"
says Kinney.  "We will double check that possibility with more
observations."  HST's ultraviolet sensitivity allowed this spectrum to
be distinguished more easily from the galaxy's starlight and other
components. 

Kinney emphasizes that it is probably more than coincidence to find a
quasar embedded in the nearest extremely powerful radio galaxy to
Earth.  She says these results suggest that quasars might be common to
radio galaxies and might explain their powerful radio emissions. 

Though this provides an unexpected opportunity for close-up study of
the mysterious "engine" behind a quasar, these results add further
mystery as to the true nature of the powerhouse. 

Previous ground-based radio observations show that there is an
elongated optical object in the Cygnus A's core.  This is inconsistent
with black hole models that predict a compact point source of
radiation.  Supermassive black holes are leading candidates for
explaining a quasar's prodigious outpouring of energy. 

The astronomers plan to use the Hubble Space Telescope to study the
spectrum of other radio galaxies and look for fingerprints of other
quasars. 

                          * * * * * * * * * * * *

The Space Telescope Science Institute is operated by the Association
of  Universities for Research in Astronomy, Inc. (AURA) for NASA,
under contract with the Goddard Space Flight Center, Greenbelt, MD. 
The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA). 

% ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ======
% Date: Wed, 21 Sep 1994 13:26:22 -0500 (EST)
% From: [email protected]
% Subject: HST UNCOVERS HIDDEN QUASAR IN NEARBY GALAXY
% To: distribution:;@us1rmc.bb.dec.com (see end of body)
% Message-Id: <[email protected]>

From: [email protected] (Peter Yee)
Subject: Hubble yields secrets of star birth in the early universe [Release 94-171] (Forwarded)
Date: 2 Nov 1994 01:57:23 -0800
Organization: NASA Ames Research Center, Moffett Field, CA
 
Don Savage
Headquarters, Washington, DC           October 17, 1994
(Phone:  202/358-1547)
 
Jim Elliott
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-6256)
 
Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone:  410/338-4514)
 
 
RELEASE:  94-171
 
HUBBLE YIELDS SECRETS OF STAR BIRTH IN THE EARLY UNIVERSE
 
 
       NASA's Hubble Space Telescope has provided new insights into
how stars might have formed many billions of years ago in the early
universe.  Hubble observations of a pair of star clusters suggest a
new link in the stellar evolution processes.
 
       The pair of clusters are 166,000 light-years away from Earth in
the southern hemisphere constellation, Doradus, within the Large
Magellanic Cloud (LMC).  The clusters are unusually close together for
being distinct and separate objects, according to Hubble astronomers.
 
       A preliminary assessment of the HST observation indicates that
these two compact clusters contain many more massive stars than
expected.  "If this were also the case billions of years ago, it could
have altered drastically the early history of the universe," says Dr.
Nino Panagia of the Space Telescope Science Institute (STScI) in
Baltimore, MD, and the European Space Agency (ESA).
 
       Panagia, R. Gilmozzi (also of STScI/ESA) and their
co-investigators utilized HST's unique capabilities -- ultraviolet
sensitivity, ability to see faint stars, and high resolution -- to
identify three separate populations in this concentration of nearly
10,000 stars.  (Previous observations with ground-based telescopes
have been able to resolve less than 1,000 stars in this region.)
 
       About 60 percent of these stars belong to the dense cluster
called NGC 1850, estimated to be 50 million years old.  However,
Hubble found that a loose distribution of extremely hot, massive stars
in a separate cluster  within the same region --representing about 20
percent of the stars in the Hubble image--are only about 4 million
years old.  (The third group of stars observed by Hubble are simple
field stars in the LMC.)
 
       The significant difference between the ages of the two clusters
suggests that they are two separate star groups that lie along the
same line of sight.  The younger, more open cluster probably lies 200
light-years beyond the older cluster, says Panagia, because if it were
in the foreground, then dust from the younger cluster would obscure
stars in the older cluster.
 
       Having two well-defined star populations separated by such a
small gap of space is very unusual.  This juxtaposition suggests that
the clusters might be linked in an evolutionary sense.  The possible
scenario proposed by the Hubble researchers is that an expanding
"bubble" of hot gas from more than 1,000 supernova explosions in the
older cluster triggered the birth of the younger cluster.
 
       The bubble expanded across space for 45 million years before
plowing into a wall of cool gas and dust.  The resulting shock front
then caused the gas to contract and precipitate a new generation of
star formation.  The massive, hot stars produced by this contraction
are destined to explode in a few million years, and thus create yet
another expanding bubble of gas.
 
       Previously, such detailed studies of stellar population were
restricted to nearby star-forming regions within the plane of our
Milky Way Galaxy.  However, Hubble's high-quality images enable these
studies to be extended a hundred times farther into the universe, out
to the distance of a neighboring galaxy.
 
       The LMC is a natural laboratory for studying the birth and
evolution of stars because it lies outside the clutter of the Milky
Way and its stars have few heavy elements, so their composition is
believed to be more like the primordial stars that formed in the early
universe.
 
       The findings will be published in the Nov. 1, 1994 issue of the
Astrophysical Journal Letters.
 
       Co-investigators are R. Gilmozzi (STScI, Baltimore, MD and
ESA), E.K. Kinney (STScI); S.P. Ewald (California Institute of
Technology, Pasadena, CA), N. Panagia (STScI and ESA, and University
of Catania, Italy); and M. Romaniello (University of Pisa, Italy).
 
       The Hubble Space Telescope is a project of international
cooperation between NASA and the ESA.

From: [email protected] (Peter Yee)
Subject: Important step taken to determine age, size of universe [Release 94-180] (Forwarded)
Date: 2 Nov 1994 02:11:25 -0800
Organization: NASA Ames Research Center, Moffett Field, CA
 
Donald Savage
Headquarters, Washington, DC         October 26, 1994
(Phone:  202/358-1547)
 
Jim Elliott
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-6256)
 
Ray Villard
Space Telescope Science Institute, Baltimore
(Phone:  410/338-4562)
 
RELEASE:  94-180
 
IMPORTANT STEP TAKEN TO DETERMINE AGE, SIZE OF UNIVERSE
 
       Astronomers using NASA's Hubble Space Telescope (HST) have taken an 
important step toward determining the age and size of the universe.
 
        They announced today that they have been able to calculate with 
considerable precision the distance to a remote galaxy, M100, in the Virgo 
cluster of galaxies.
 
        The ability to make accurate distance measurements over vast reaches 
of space will help provide a precise calculation of the expansion rate of the 
universe, called the Hubble Constant, which is crucial to determine the age and
size of the universe.
 
       "Although this is only the first step in a major systematic program to 
measure accurately the scale, size, and age of the universe," noted Dr. Wendy 
L. Freedman, of the Observatories of the Carnegie Institution of Washington, "a
firm distance to the Virgo cluster is a critical milestone for the 
extragalactic distance scale, and it has major implications for the Hubble 
Constant."
 
       HST's detection of Cepheid variable stars in the spiral galaxy M100, a 
member of the Virgo cluster, establishes the distance to the cluster as 56 
million light-years (with an uncertainty of +/- 6 million light-years).
M100 is now the most distant galaxy in which Cepheid variables have been 
measured accurately.
 
       The precise measurement of this distance allows astronomers to 
calculate that the universe is expanding at the rate of 80 km/sec per 
megaparsec (+/- 17 km/sec).  For example, a galaxy one million light-years 
away will appear to be moving away from us at approximately 60,000 miles per
hour.  If it is twice that distance, it will be seen to be moving at twice the 
speed, and so on.  This rate of expansion is the Hubble Constant.
 
       These results are being published in the Oct. 27 issue of the journal, 
"Nature."  The team of astronomers is jointly led by Freedman, Dr. Robert 
Kennicutt (Steward Observatory, University of Arizona), and Dr. Jeremy Mould 
(Mount Stromlo and Siding Spring Observatories, Australian National
University).
 
       Dr. Mould noted, "Those who pioneered the development of the Hubble 
Space Telescope in  the 1960s and 1970s recognized its unique potential for 
finding the value of the Hubble Constant.  Their foresight has been rewarded 
by the marvelous data that we have obtained for M100."
 
       Using Hubble's Wide-Field and Planetary Camera (WFPC2), the team of 
astronomers repeatedly imaged a field where much star formation recently had 
taken place, and was, therefore, expected to be rich in Cepheids  -- a class of
pulsating stars used for determining distances.  Twelve one-hour exposures, 
strategically placed in a two-month observing window, resulted in the 
discovery of 20 Cepheids.  About 40,000 stars were measured in the search for 
these rare, but bright, variables.  Once the periods and intrinsic brightness
of these stars were established from the careful measurement of their 
pulsation rates, the researchers calculated a distance of 56 million light-years 
to the galaxy.  (The team allowed for the dimming effects of distance as well 
as that due to dust and gas between Earth and M100.)
 
       Many complementary projects are currently being carried out from the 
ground with the goal of also providing values for the Hubble Constant.  However, 
they are subject to many uncertainties which HST was designed and built to
circumvent.  For example, a team of astronomers using the Canada-France-Hawaii
telescope at Mauna Kea recently has arrived at a distance to another galaxy in 
Virgo that is similar to that found for M100 using HST -- but their result
is tentative because it is based on only three Cepheids in crowded star fields.
 
       "Only Space Telescope can make these types of observations routinely," 
Freedman explained.  "Typically, Cepheids are too faint and the resolution too 
poor, as seen from ground-based telescopes, to detect Cepheids clearly in a
crowded region of a distant galaxy."
 
       Although M100 is now the most distant galaxy in which Cepheid variables 
have been discovered, the Hubble team emphasized that the HST project must 
look into even more distant galaxies before a definitive number can be agreed on
for the age and size of the universe.  This is because the galaxies around the 
Virgo Cluster are perturbed by the large mass concentration of galaxies near 
the cluster.  This influences their rate of expansion.
 
REFINING THE HUBBLE CONSTANT
 
       These first HST results are a critical step in converging on the true 
value of the Hubble Constant, first developed by the American astronomer Edwin 
Hubble in 1929. Hubble found that the farther away a galaxy is, the faster it
is receding away from us.  This "uniform expansion" effect is strong evidence 
the universe began in an event called the "Big Bang" and that the universe has 
been expanding ever since.
 
       To calculate accurately the Hubble Constant, astronomers must have two 
key numbers: the recession velocities of galaxies and their distances as 
estimated by one or more cosmic "mileposts," such as Cepheids.  The age of
the universe can be estimated from the value of the Hubble Constant, but it is 
only as reliable as the accuracy of the distance measurements.
 
       The Hubble Constant is only one of several key numbers needed to 
estimate the universe's age.  For example, the age also depends on the average 
density of matter in the universe, though to a lesser extent.
 
       A simple interpretation of the large value of the Hubble Constant, as 
calculated from HST observations, implies an age of about 12 billion years for 
a low-density universe, and 8 billion years for a high-density universe.  
However, either value highlights a long-standing dilemma.  These age estimates 
for the universe are shorter than the estimated ages of some of the oldest 
stars found in the Milky Way and in globular star clusters orbiting our Milky 
Way. Furthermore, small age values pose problems for current theories about 
the formation and development of the observed large-scale structure of the 
universe.
 
COSMIC MILEPOSTS
 
       Cepheid variable stars rhythmically change in brightness over intervals 
of days (the prototype is the fourth brightest star in the circumpolar 
constellation Cepheus).  For more than half a century, from the early work
of astronomers Edwin Hubble, Henrietta Leavitt, Allan Sandage, and Walter 
Baade, it has been known that there is a direct link between a Cepheid's 
pulsation rate and its intrinsic brightness.  Once a star's true brightness is
known, its distance is a relatively straightforward calculation because the 
apparent intensity of light drops off at a geometrically predictable rate with 
distance.  Although Cepheids are rare, once found, they provide a very reliable
"standard candle" for estimating intergalactic distances, according to 
astronomers.
 
       Besides being an ideal hunting ground for the Cepheids, M100 also 
contains other distance indicators that can in turn be calibrated with the 
Cepheid result.  This face-on, spiral galaxy has been host to several 
supernovae, which are also excellent distance indicators.  Individual 
supernovae (called Type II, massive exploding stars) can be seen to great 
distances, and can be used to extend the cosmic distance scale well beyond 
Virgo.
 
       As a crosscheck on the HST results, the distance to M100 has been 
estimated using the Tully-Fisher relation (a means of estimating distances to 
spiral galaxies using the maximum rate of rotation to predict the intrinsic 
brightness) and this independent measurement also agrees with both the
Cepheid and supernova "yardsticks."
 
       HST Key Projects are scientific programs that have been widely 
recognized as being of the highest priority for the HST and have been 
designated to receive a substantial amount of observing time on the telescope.  
The Extragalactic Distance Scale Key Project involves discovering Cepheids in a
variety of important calibrating galaxies to determine their individual 
distances.  These distances then will be used to establish an accurate value 
of the Hubble Constant.
 
       The Key Project Team on the Extragalactic Distance Scale consists of 
Sandra Faber, Garth Illingworth and Dan Kelson (Univ. of California, Santa 
Cruz), Laura Ferrarese & Holland Ford (Space Telescope Science Institute), Wendy
Freedman, John Graham, Robert Hill and Randy Phelps (Carnegie Institution of 
Washington), James Gunn (Princeton University), John Hoessel and Mingsheng Han 
(University of Wisconsin), John Huchra (Harvard-Smithsonian Center for 
Astrophysics), Shaun Hughes (Royal Greenwich Observatory), Robert Kennicutt, 
Paul Harding, Anne Turner and Fabio Bresolin (Univ. of Arizona), Barry Madore 
and Nancy Silbermann (JPL, Caltech), Jeremy Mould (Mt. Stromlo, Australian 
National University), Abhijit Saha (Space Telescope Science Institute), and 
Peter Stetson (Dominion Astrophysical Observatory).
 
       The Space Telescope Science Institute is operated by the Association of 
Universities for Research in Astronomy, Inc., for NASA, under contract with 
the Goddard Space Flight Center, Greenbelt, MD.  The HST is a project of 
international cooperation between NASA and the European Space Agency.
 
       The Wide Field and Planetary Camera 2 was developed by NASA's Jet 
Propulsion Laboratory, Pasadena, CA, and is managed by the Goddard Space 
Flight Center for NASA's Office of Space Science, Washington, DC.

Donald Savage
Headquarters, Washington, DC           November 15, 1994
(Phone:  202/358-1547)
 
Jim Elliott
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-6256)
 
Ray Villard
Space Telescope Science Institute, Baltimore
(Phone:  410/338-4562)
 
RELEASE:  94-188
 
HUBBLE RULES OUT A LEADING EXPLANATION FOR DARK MATTER
 
       Two teams of astronomers, working independently with NASA's Hubble 
Space Telescope (HST), have ruled out the possibility that red dwarf stars 
constitute the invisible matter, called dark matter, believed to account for 
more than 90 percent of the mass of the universe.
 
       Until now, the dim, small stars were considered ideal candidates for 
dark matter.  Whatever dark matter is, its gravitational pull ultimately will 
determine whether the universe will expand forever or will someday collapse.
 
       "Our results increase the mystery of the missing mass.  They rule out a 
popular but conservative interpretation of dark matter," said Dr. John Bahcall, 
professor of natural science at the Institute of Advanced Study, Princeton, NJ, 
and leader of one of the teams.
 
       The group, led by Bahcall and Andrew Gould of Ohio State University, 
Columbus, OH, (formerly of the Institute for Advanced Study), showed that 
faint red dwarf stars, which were thought to be abundant, actually are sparse 
in the Earth's home galaxy, and in the universe by inference.
 
       The team, led by Dr. Francesco Paresce of the Space Telescope Science 
Institute in Baltimore, MD, and the European Space Agency, determined that the 
faint red stars rarely form and that there is a cutoff point below which 
nature does not make this type of dim, low-mass star.
 
       The space telescope observations involved accurately counting stars and 
gauging their brightness.  The observations overturn several decades of 
conjecture, theory and observation about the typical mass and abundance of the 
smallest stars in the universe.
 
PREVIOUS GROUND-BASED RESULTS INCONCLUSIVE
 
       In our own stellar neighborhood, there are almost as many red dwarfs as 
there are all other types of stars put together. The general trend throughout 
our galaxy is that small stars are more plentiful than larger stars, just as 
there are more pebbles on the beach than rocks.  This led many astronomers to 
believe that they were only seeing the tip of the iceberg and that many more 
extremely faint red dwarf stars were at the limits of detection with 
ground-based instruments.
 
       According to stellar evolution theory, stars as small as eight percent 
of the mass of the Sun are still capable of shining by nuclear fusion processes.
 
       Over the past two decades, theoreticians have suggested that the lowest 
mass stars also should be the most prevalent and therefore might provide a 
solution for dark matter.  This seemed to be supported by previous observations 
with ground-based telescopes that hinted at an unexpected abundance of what 
appeared to be red stars at the faintest detection levels achievable from the 
ground.
 
       However, these prior observations were uncertain because the light from 
these faint objects is blurred slightly by Earth's turbulent atmosphere.  This 
makes the red stars appear indistinguishable from the far more distant, 
diffuse-looking galaxies.
 
PINNING DOWN THE LONG-SOUGHT HALO POPULATION
 
       Hubble's capabilities made it possible for the team of astronomers led 
by Bahcall and Gould to observe red stars that are 100 times dimmer than those 
detectable from the ground -- a level where stars can be distinguished easily 
from galaxies.  Hubble Space Telescope's extremely high resolution also can 
separate faint stars from the much more numerous galaxies by resolving the 
stars as distinct points of light, as opposed to the "fuzzy" extended signature
of a remote galaxy.
 
       Bahcall and Gould, with their colleagues Chris Flynn and Sophia Kirhakos 
(also of the Institute for Advanced Study, Princeton) used images of random 
areas in the sky taken with the HST Wide Field Planetary Camera 2 while the 
telescope was performing scheduled observations with other instruments.  By 
simply counting the number of faint stars in the areas observed by HST, the 
scientists demonstrated that the Milky Way has relatively few faint red stars.
 
       The HST observations show that dim red stars make up no more than six 
percent of the mass in the halo of the Galaxy, and no more than 15 percent of 
the mass of the Milky Way's disk.  The Galactic halo is a vast spherical 
region that envelops the Milky Way's spiral disk of stars, of which Earth's 
Sun is one inhabitant.
 
FAINT RED STARS MISSING FROM A GLOBULAR CLUSTER
 
       By coincidence, Paresce pursued the search for faint red dwarfs after 
his curiosity was piqued by an HST image taken near the core of the globular 
cluster NGC 6397.  He was surprised to see that the inner region was so devoid 
of stars, he could see right through the cluster to far more distant background 
galaxies.  Computer simulations based on models of stellar population predicted 
the field should be saturated with dim stars-- but it wasn't.
 
       HST's sensitivity and resolution allowed Paresce, and co-investigators 
Guido De Marchi (Space Telescope Science Institute and the University of 
Firenze, Italy), and Martino Romaniello (University of Pisa, Italy) to conduct 
the most complete study to date of the population of the cluster (globular 
clusters are ancient, pristine laboratories for studying stellar evolution).  
To Paresce's surprise, he found that stars 1/5 the mass of our Sun are very 
abundant -- there are about 100 stars this size for every single star the mass 
of our Sun -- but that stars below that range are rare.  "The very small stars 
simply don't exist," he said.
 
       A star is born as a result of the gravitational collapse of a cloud of 
interstellar gas and dust.  This contraction stops when the infalling gas is 
hot and dense enough to trigger nuclear fusion, causing the star to glow and 
radiate energy. "There must be a mass limit below which the material is 
unstable and cannot make stars," Paresce emphasizes.  "Apparently, nature 
breaks things off below this threshold."
 
       Paresce has considered the possibility that very low-mass stars formed 
long ago but were thrown out of the cluster due to interactions with more 
massive stars within the cluster, or during passage through the plane of our 
Galaxy.  This process would presumably be common among the approximately 150 
globular clusters that orbit the Milky Way.  However, the cast-off stars 
would be expected to be found in the Milky Way's halo, and Bahcall's HST 
results don't support this explanation.
 
THE SEARCH FOR DARK MATTER
 
       The HST findings are the latest contribution to a series of recent, 
intriguing astronomical observations that are struggling to pin down the 
elusive truth behind the universe's "missing mass."
 
       Models describing the origin of helium and other light elements during 
the birth of the universe, or "Big Bang," predict that less than 5% of the 
universe is made up of "normal stuff," such as neutrons and protons.  This 
means more than 90% of the universe must be some unknown material that does 
not emit any radiation that can be detected by current instrumentation.  
Candidates for dark matter include black holes, neutron stars and a variety of 
exotic elementary particles.
 
       Within the past year, astronomers have uncovered indirect evidence for 
a dark matter candidate called a MACHO (MAssive Compact Halo Objects).  These 
previous observations detected several instances of an invisible object that 
happens to lie along the line of sight to an extragalactic star.  When the 
intervening object is briefly aligned between Earth and a distant star, it 
amplifies, or gravitationally lenses, the light from the distant star.
 
       The new HST finding shows that faint red stars are not abundant enough 
to explain the gravitational lensing events attributed to MACHOs.  Bahcall 
cautions, however, that his results do not rule out other halo objects that 
could be smaller than the red stars such as brown dwarfs -- objects not massive 
enough to burn hydrogen and shine in visible light.
 
       Additional circumstantial evidence for dark matter in the halo of our 
galaxy has been inferred from its gravitational influence on the motions of 
stars within the Milky Way's disk.  Recently, this notion was further supported 
by ground-based observations, made by Peggy Sachett of the Institute for 
Advanced Study, that show a faint glow of light around a neighboring spiral 
galaxy that is the shape expected for a halo composed of dark matter.  This 
could either be light from the dark matter itself or stars that trace the 
presence of the galaxy's dark matter.
 
       The reality of dark matter also has been inferred from the motions of 
galaxies in clusters, the properties of high-temperature gas located in 
clusters of galaxies and from the relative amounts of light elements and 
isotopes produced in the Big Bang.
 
       The ultimate fate of the universe will be determined by the amount of 
dark matter present.  Astronomers have calculated that the amount of matter -- 
planets, stars and galaxies -- observed in the universe cannot exert enough 
gravitational pull to stop the expansion which began with the Big Bang.  
Therefore, if the universe contains less than a critical density of matter, it 
will continue expanding forever, but if enough of the mysterious dark matter 
exists, the combined gravitational pull someday will cause the universe to stop
expanding and eventually collapse.
 
       Bahcall stresses, "The dark matter problem remains one of the 
fundamental puzzles in physics and astronomy.  Our results only sharpen the 
question of what is the dark matter."
 
       Bahcall's results appeared in the November 1, 1994 issue of the
Astrophysical Journal.  Paresce's paper will appear in the February 10, 1995, 
issue of the Astrophysical Journal.
 
       The Space Telescope Science Institute is operated by the Association of 
Universities for Research in Astronomy, Inc. (AURA) for NASA, under contract 
with the Goddard Space Flight Center, Greenbelt, MD.  The Hubble Space 
Telescope is a project of international cooperation between NASA and the 
European Space Agency (ESA).

European Space Agency
Press Release No.47-94
Paris, 16 December 1994
 
Hubble finds one of smallest stars in the Universe
 
This picture taken by the European Space Agency's faint object camera on-board 
the Hubble Space Telescope* resolves, for the first time, one of the smallest 
stars in our Milky Way galaxy. Called G1623b the diminutive star (right of 
center) is ten times less massive than the Sun, and 60,000 times fainter. (If 
it were as far away as the Sun it would only be eight times brighter than the 
Full Moon).
 
Located 25 light years away, in the constellation Hercules, G1623b is the 
smaller component of a double star system, where the separation between the 
two members is only twice the distance between Earth and the Sun 
(approximately 300 million Km). The small star completes one orbit about its
larger companion every four years.
 
G1623b was first detected, indirectly, from previous astrometric observations 
that measured the wobble of the primary star due to the gravitational pull of 
its smaller, invisible companion. However the star is too dim and too close to 
its companion star to be seen by ground-based telescopes. Hubble's view is 
sharp enough to separate the small star from its companion.
 
The new Hubble observations will allow astronomers to measure the intrinsic 
brightness and mass of G1623b. This will lead to a better understanding of the 
formation and evolution of the smallest stars currently known. Red dwarf stars 
were once thought to be the most abundant stars in the Galaxy. However, recent 
Hubble observations show that these low mass stars are surprisingly rare
 

 
CONTACT:  Ray Villard, STScI
          (410) 338-4514                            Tuesday, December 6, 1994
 
          Duccio Macchetto, STScI       PRESS RELEASE NO.:  STScI-PR94-52
          (410) 338-4790
 
          Alan Dressler, Carnegie Institutions of Washington
          (818) 304-0245
 
          Mark Dickinson, STScI
          (410) 338-4992
 
 
HUBBLE IDENTIFIES PRIMEVAL GALAXIES, UNCOVERS NEW CLUES TO THE UNIVERSE'S 
EVOLUTION
 
 
Astronomers using NASA's Hubble Space Telescope as a "time
machine" have obtained the clearest views yet of distant galaxies
that existed when the universe was a fraction of its current age.
 
A series of remarkable pictures, spanning the life history of the
cosmos, are providing the first clues to the life history of galaxies.
The Hubble results suggest that elliptical galaxies developed remarkably
quickly into their present shapes. However, spiral galaxies that existed
in large clusters evolved over a much longer period -- the majority being
built and then torn apart by dynamic processes in a restless universe.
 
Astronomers, surprised and enthusiastic about these preliminary
findings, anticipate that Hubble's observations  will  lead to a better
understanding of the origin, evolution, and eventual fate of the
universe.  The Hubble observations challenge those estimates for
the age of the universe that do not allow enough time for the galaxies
to form and evolve to the maturity seen at an early epoch by Space
Telescope.
 
"These unexpected results are likely to have a large influence on our
cosmological  models and theories of galaxy formation," says Duccio
Macchetto of the European Space Agency and the Space Telescope
Science Institute (STScI).  "These Hubble telescope images are
sufficient to provide a first determination of the properties of these
very young and distant galaxies."
 
"This is compelling, direct visual evidence that the universe is truly
changing as it ages, as the Big Bang model insists," emphasizes
Alan Dressler of the Carnegie Institutions, Washington, D.C.  "Though
much of the quantitative work can be done best with large Earth-bound
telescopes, Hubble Space Telescope is providing our first view of the
actual forms and shapes of galaxies when they were young."
 
"These initial results are surprising," adds Mauro Giavalisco (STScI).
"Hubble is giving us, for the first time, a chance to study in great detail
the properties of very young galaxies and understand the mechanisms
of their formation."
 
A series of  long exposures, taken by separate teams led by  Macchetto,
Dressler, and Mark Dickinson (STScI)  trace galaxy evolution  in rich
clusters that existed when the universe was approximately one-tenth,
one-third, and two-thirds its present age.  Their key findings:
 
     Scientists identified the long-sought population of primeval galaxies
     that began to form less than one billion years after the Big Bang.
 
     One of the deepest images ever taken of the universe reveals a
     cosmic zoo" of bizarre fragmentary objects in a remote cluster
     that are the likely ancestors of our Milky Way Galaxy.
 
     A series of pictures, showing galaxies at different epochs, offers the
    most direct evidence to date for dynamic galaxy evolution driven by
    explosive bursts of star formation, galaxy collisions, and other
    interactions, which ultimately created and then destroyed  many
    spiral galaxies that inhabited rich clusters.
 
 
 
Postcards from Edge of Space and Time
 
The researchers used Hubble as a powerful "time machine" for probing
the dim past. The astronomical equivalent of digging through geologic
strata on Earth,  Hubble peers across  a large volume of the observable
universe and resolves thousands of galaxies from five to twelve billion
light-years away.  Because their light has taken billions of years to cross
the expanding universe, these distant galaxies are  fossil evidence,"
encoded in starlight, of events that happened  long ago.
 
These long-exposure Hubble images will help test and verify ideas
about galaxy evolution based on several decades of conjecture,
theoretical modeling, and ground-based observation.    Ground-based
observations have not been able to establish which of several
competing theories best describe how galaxies formed and evolved
in the early universe.
 
Though the largest ground-based telescopes can detect objects at great
distances, only Hubble can reveal the shapes of these remote objects by
resolving structures a fraction of the size of our Milky Way Galaxy. This
is allowing astronomers, for the first time, to discriminate among various
types of  distant galaxies and trace their evolution. Like watching
individual frames of a motion picture, the Hubble pictures reveal the
emergence of structure in the infant universe, and the subsequent
dynamic stages of galaxy evolution.
 
Now that Hubble has clearly shown that it is an exquisite time machine
for seeking our cosmic "roots," astronomers are anxious to push back
the frontiers of time and space even further. "Our goal now is to look
back  further than twelve billion years to see what we are sure will be
even more dramatic evidence of galaxies in formation,"  says Dressler.
 
                                * * * * * *
The Space Telescope Science Institute (STScI) is operated by the
Association of Universities for Research in Astronomy, Inc. (AURA)
for NASA, under contract with the Goddard Space Flight Center,
Greenbelt, MD.   The Hubble Space Telescope is a project of
international cooperation between NASA and the European
Space Agency (ESA).
 
                                * * * * * *
 
NASA press releases and other information are available automatically
by sending an Internet electronic mail message to [email protected].
In the body of the message (not the subject line) users should type
the words "subscribe press-release" (not quotes).  The system will
reply with a confirmation via E-mail of each subscription.  A second
automatic message will include additional information on the service.
Questions should be directed to (202) 358-4043.
 
 
To electronically access this press release and associated captioned
images and background information, you can use the Internet or
World Wide Web.
 
Image files are on ftp.stsci.edu in the directory /stsci/epa/gif:
 
     PR#                      GIF file            Caption text
     STScI-PRC94-52a          GalaxEvA.gif        GalaxEvA.txt
     STScI-PRC94-52b          GalaxEvB.gif        GalaxEvB.txt
     STScI-PRC94-52c          GalaxEvC.gif        GalaxEvC.txt
     STScI-PRC94-25           GalaxEvD.gif        GalaxEvD.txt
 
The press release text is in the file /stsci/epa/press-releases/94-52.
 
The same data is available using WWW/Mosaic, which is always
accessible via:
 
          http://www.stsci.edu/EPA/OPO.html
 
or to get right to the latest release:
 
          http://www.stsci.edu/EPA/OPO/Latest.html
 
 
PHOTO RELEASE NO.:  STScI-PR94-52A
DECEMBER 6, 1994
 
                       DISTANT CLUSTER OF GALAXIES
[left]
One of the deepest images to date of the universe, taken with NASA's
Hubble Space Telescope (HST), reveals thousands of faint galaxies at
the detection limit of present day telescopes.  Peering across a large
volume of the observable cosmos, Hubble resolves thousands of
galaxies from five to twelve billion light-years away.  The light from
these remote objects has taken billions of years to cross the
expanding universe, making these distant galaxies  fossil evidence"
of events that  happened when the universe was one-third its
present age.
 
A fraction of the galaxies in this image belong to a cluster located
nine billion light-years away. Though the field of view (at the
cluster's distance) is only two million light-years across, it contains
a multitude of fragmentary objects. (By comparison, the two million
light-years between our Milky Way galaxy and its nearest large
companion galaxy, in the constellation Andromeda, is essentially
empty space!)
 
Very few of the cluster's members are recognizable as normal
spiral galaxies (like our Milky Way), although some elongated
members might be edge-on disks.  Among this  zoo  of  odd
galaxies are ``tadpole-like'' objects, disturbed and apparently merging
systems dubbed "train-wrecks," and a multitude of faint, tiny shards
and fragments,  dwarf galaxies or possibly an unknown population
of objects. However, the cluster also contains red galaxies that
resemble mature examples of today's elliptical galaxies. Their red
color comes from older stars that must have formed shortly after
the Big Bang.
 
The image is the full field view of the Wide Field and Planetary
Camera-2. The picture was taken in intervals between May 11
and June 15, 1994 and required an 18-hour long exposure, over 32
orbits of HST,  to reveal objects down to 29th magnitude.
 
[bottom right]
A close up view of the peculiar radio galaxy 3C324 used to locate the
cluster. The galaxy is nine billion light-years away as measured by
its spectral redshift (z=1.2), and located in the constellation Serpens.
Based on the colors and the statistical distribution of the galaxies in
3C 324's vicinity, astronomers conclude a remote cluster is at the same
distance as a radio galaxy.
 
[center right]
This pair of elliptical galaxies, seen together with a few fainter
companions, is remarkably similar in shape, light distribution, and
color to their present day descendants. This Hubble image provides
evidence that ellipticals formed remarkably early in the universe.
 
[top right]
Some of the objects in this compact tangled group resemble today's
spiral galaxies.  However, they have irregular shapes and appear
disrupted and asymmetric. This might be due to a high frequency
of galaxy collisions and close encounters in the early universe.
 
Credit: Mark Dickinson (STScI) and NASA
PHOTO RELEASE NO.:  STScI-PR94-52B
DECEMBER 6, 1994
 
 
                          GALAXIES IN THE YOUNG UNIVERSE
[left]
This image of a small region of the constellation Sculptor, taken with a
ground-based photographic sky survey camera, illustrates the
extremely small angular size of a distant galaxy cluster in the night sky.
Though this picture encompasses a piece of the sky about the width of
the bowl of the Big Dipper, the cluster is so far away it fills a sky area
only 1/10th the diameter of the Full Moon.   The cluster members are
not visible because they are so much fainter than foreground stars.
 
[center]
A NASA Hubble Space Telescope (HST) image of the  farthest cluster
of galaxies in the universe, located at a distance of 12 billion light-years.
Because the light from these remote galaxies has taken 12 billion years
to reach us, this image is a remarkable glimpse of the primeval universe,
at it looked about two billion years after the Big Bang. The cluster
contains 14 galaxies, the other objects are largely foreground galaxies.
The galaxy cluster lies in front of  quasar Q0000-263 in the constellation
Sculptor. Presumably the brilliant core of an active galaxy, the quasar
provides a beacon for searching for primordial galaxy clusters.
 
The image is the full field view of the Wide Field and Planetary
Camera-2,  taken on September 6, 1994. The 4.7-hour exposure reveals
objects down to 28.5 magnitude.
 
[right]
This enlargement shows one of the farthest  normal  galaxies yet
detected, (blob at center right) at a distance of 12  billion light-years
(redshift of z=3.330). The galaxy lies 300 million light-years in front
of the quasar Q0000-263 (z=4.11, large white blob and spike on
left side of frame) and was detected because it absorbs some light
from the quasar.  The galaxy's spectrum reveals that vigorous star
formation is taking place.
 
Credit: Duccio Macchetto (ESA/STScI), Mauro Giavalisco (STScI),
and NASA
 
 
PHOTO RELEASE NO.:   STScI-PR94-52C
DECEMBER 6, 1994
 
 
                            GALAXIES: SNAPSHOTS IN TIME
 
This sequence of NASA Hubble Space Telescope (HST) images of
remote galaxies offers tantalizing initial clues to the evolution of galaxies
in the universe.
 
[far left column]
These are traditional spiral and elliptical-shaped galaxies that make up
the two basic classes of  island star cities that inhabit the universe we
see in our current epoch (14 billion years after the birth of the universe
in the Big Bang).  Elliptical galaxies contain older stars, while spirals
have vigorous ongoing star formation in their dusty, pancake-shaped
disks. Our Milky Way galaxy is a typical spiral, or disk-shaped galaxy,
on the periphery of the great Virgo cluster. Both galaxies in this column
are a few tens of millions of light-years away, and therefore represent
our current stage of the universe s evolution.
 
[center left column]
These galaxies existed in a rich cluster when the universe was
approximately two-thirds its present age. Elliptical galaxies (top)
appear fully evolved because they resemble  today's descendants.  By
contrast, some spirals have a  frothier  appearance, with loosely shaped
arms of young star formation. The spiral population appears more
disrupted due to a variety of possible dynamical effects that result
from dwelling in a dense cluster.
 
[center right column]
Distinctive spiral structure appears more vague and disrupted in
galaxies that existed when the universe was nearly one-third its present
age. These objects do not have the symmetry of current day spirals
and contain irregular lumps of starburst activity.   However, even this far
back toward the beginning of time, the elliptical galaxy (top) is still
clearly recognizable.  However, the distinction between ellipticals and
spirals grows less certain with increasing distance.
 
[far right column]
These extremely remote, primeval objects existed with the universe was
nearly one-tenth its current age. The distinction between spiral and
elliptical galaxies may well disappear at this early epoch. However, the
object in the top frame has the light profile of a mature elliptical galaxy.
This implies that ellipticals formed remarkably early in the universe
while spiral galaxies took much longer to form.
 
Credit: A. Dressler (Carnegie Institutions of Washington),
M. Dickinson (STScI), D. Macchetto (ESA/STScI), M. Giavalisco
(STScI), and NASA
 
Hubble Uncovers New Clues to Galaxy Formation
 
     National Aeronautics and
     Space Administration
 
     NASA Headquarters
     Washington, D.C.                                          December 1994
 
 
 
                   SCIENCE BACKGROUND
 
 
     The Paradox: Grown-Up Galaxies in an Infant Universe
 
Hubble Space Telescope's recent observations identify fully formed
elliptical galaxies in a pair of  primordial galaxy clusters that have been
surveyed by teams lead by Mark Dickinson of the Space Telescope
Science Institute and Duccio Macchetto of the European Space Agency
and the Space Telescope Science Institute.  Although the clusters were
first thought to be extremely distant because of  independent ground-
based observations, the Hubble images provide sharp enough details
to confirm what was only suspected previously.
 
The surprise is that elliptical galaxies appeared remarkably "normal"
when the universe was a fraction of its current age, meaning that they
must have formed a short time after the Big Bang.
 
Dickinson, in studying a cluster that existed when the universe was
nearly one-third its current age, finds that its red galaxies resemble
ordinary elliptical galaxies, the red color coming from a population
of older stars.
 
This has immediate cosmological implications, since the universe
must have been old enough to accommodate them.  Cosmologies with
high values for the rate of expansion of  space (called  the  Hubble
Constant, which is needed for calculating the age of the universe)
leave little time  for these galaxies to form and evolve to the maturity
we're seeing in the Hubble image,"   Dickinson emphasizes.
 
Macchetto's observation of a galaxy that existed 12 billion years ago,
or nearly one-tenth the universe's present age, also finds a light
distribution remarkably similar to today's elliptical galaxies. "This
seems to show that elliptical galaxies reach their 'mature' shape very
quickly, during a robust burst of star formation, and then evolve
passively," says Mauro Giavalisco of the Space Telescope Science
Institute.  "Astronomers suspected that this was the case for at least
some ellipticals.  Now, Hubble has  found direct evidence for it."
 
To produce such a shape in a galaxy requires one billion years for the
gas to settle into the center of the galaxy's gravitational field.  Therefore,
these galaxies, which we observe as they were less than two billion years
after the Big Bang, were beginning to form less than one billion years
after the Big Bang!  says Macchetto.
 
"Elliptical galaxies are exceptional laboratories for studying stellar
dynamics and evolution," adds Giavalisco, "and the explanation of their
origin is still controversial. This new observational evidence is suggesting
that at least some ellipticals formed via processes such as 'violent
relaxation', where a large grouping of stars will rapidly contract into a
dense cluster. Well known from a theoretical point of view, these
mechanisms of galaxy formation appear to have been confirmed by the
images taken with the Hubble."
 
A Cosmic Zoo of Bizarre Galaxies
 
Contrary to the gravitationally "relaxed" and normal looking primordial
elliptical galaxies, the same set of Hubble images tells a remarkable story of
the creation -- and destruction -- of spiral  galaxies in large clusters.
 
In one of the longest exposures taken to date with Hubble, representing
18 hours of continuous observing, Dickinson has uncovered a
"celestial zoo" of  faint,  compact objects that might be the primordial
building blocks from which spiral galaxies such as our Milky Way
formed. These  irregular bluish fragments, dating back nine billion
years, may ultimately have coalesced into spiral galaxies, he reports.
 
"We see a bewildering range of galaxy shapes. The Hubble image is
like looking at a drop of pond water under a microscope, where we
see a menagerie of strange creatures."   Though Dickinson does not
have a direct measurement of distance, he suspects these objects
are also remote cluster members since they group closely around a
distant radio galaxy (a class of energetic galaxy with a precisely
measured distance) and do not resemble anything seen in the present
universe.
 
Very few of the bluish objects are recognizable as normal spirals,
although some elongated members might be edge-on disks, Dickinson
concludes.  Among this  zoo  are "tadpole-like'' objects, disturbed and
apparently merging systems dubbed "train-wrecks", a multitude of tiny
shards and fragments, faint dwarf galaxies or possibly an unknown
population of objects.
 
However, Dickinson cautions that the bright blue light of star formation
can dramatically affect apparent galaxy shapes at great distances
(where ultraviolet light is redshifted to visible wavelengths due to the
uniform expansion of space).  "Nevertheless, it is difficult to escape
the impression that evolutionary processes are shaping or disrupting
disk galaxies."
 
 
The Violent History of Spiral Galaxies
 
While Dickinson sees the birth of spiral galaxies, Alan Dressler's Hubble
images of several rich clusters chronicle the demise of spirals
inhabiting large clusters. "It seems that almost as soon as  nature
builds spiral galaxies in clusters, it begins tearing them apart," he says.
 
"The cause of this disappearance of spirals from clusters, from four
billion years ago to the present, is unsettled and vigorously debated.
Just the fact that the form of entire galaxies could be altered in so
short a time is important in our attempts to find out how galaxies
formed in the first place,"  Dressler concludes.
 
The evidence provided by Hubble shows that this large-scale galactic
"demolition derby" could explain why there were so many more spiral
galaxies in rich clusters long ago than there are today.   Apparently,
many spiral galaxies have since been destroyed or disappeared.
Hubble observations also reveal many unusual objects within the
clusters that can be considered fragments of galaxies.
 
"When we look back in time to these clusters, we see many distorted
galaxies -- they appear to  have been disturbed or disrupted  in one
way or another," says Dressler.  "There are so many  little shreds of
galaxies -- it almost looks like galactic debris -- flying around in these
clusters.   Perhaps this is a result of tidal encounters, but at this point
we really don't understand what's happening.   However,  the Hubble
pictures make it pretty clear that it had taken a long  time  for these
star systems to organize and that in their younger forms they were
still easily perturbed."
 
Hubble shows that spiral galaxies could not easily survive in the
dynamic environment of a dense galaxy cluster. Detailed Hubble images
show that these "fragile" disk galaxies were prone to being warped
from their pancake shape.
 
Analysis of the pictures has inspired  several alternate mechanisms
for explaining the galaxy distortion.  One possibility is that the
galaxies were disrupted by mergers and tidal interaction  caused by
close encounters between galaxies in the dense cluster.  Also, there is
evidence from  nearby clusters of galaxies that the hot, high pressure
gas residing in a cluster can work to  remove the gas in the disks of
individual spiral galaxies.
 
Finally, disk galaxies might have been stripped of their mantles of
"dark matter" (unknown material that is  probably not made up of
stars but accounts for a significant fraction of a Galaxy's mass) as
they plunge through the cluster.  Dressler points out that computer
models of  galaxies show that a spherical halo of material is important
to stabilizing a thin disk, so loss of  this material could result in the
disk warping or fracturing, diminishing the galaxy's chance of  survival
as a spiral.
 
Thankfully, galaxy "bumper cars" took place only in large clusters,
containing hundreds or even thousands of galaxies.  Our Milky Way,
one of the largest members of a Local Group of nearly  two dozen
galaxies, presumably evolved in a far less crowded region of the universe.
 
 
 Finding Primeval Galaxy Clusters
 
"We have very likely identified the long-sought population of
primeval galaxies," Macchetto  reports. Until the Hubble results,
astronomers had searched unsuccessfully for several decades for truly
primeval galaxies, which are hard to find when they are in their very early
phase of  existence.
 
"If you can find the primeval galaxies at the cosmic epoch when they
started to form and  understand their shape, mass, color and brightness,
then chances are that you will develop a  better understanding of
cosmology," comments Giavalisco.
 
Macchetto and his team used quasars (bright cores of distant active
galaxies) as beacons to look  for the "shadowing effect" of galaxies
between Earth and the quasar. Their search strategy is based on the
theory that the first galaxies to appear in the  universe were highly
clumped in  space.   Therefore, if a quasar's light is modified by an
intervening galaxy, it more than  likely belongs to a primeval cluster.
 
"All you have to do is to look around the quasar using a specially
developed optical filter,  fine-tuned to observe galaxies at the distance
suggested by the change in the quasar's light,"  Macchetto says.
 
Using this novel technique with ground-based telescopes, the team
looked at the field around quasar Q0000-263 in the constellation
Sculptor and found the farthest "normal" galaxy ever observed, at
a distance of 12 billion years.
 
This observation led Macchetto and Giavalisco to identify a whole
cluster of primeval galaxies in that region of the sky.  Remarkably,
the Hubble has shown that the cluster members are characterized by
a compact shape, supporting the idea that they all underwent a
similar mechanism of formation.
 
"The very presence of the cluster shows that these large structures
already existed two billion  years after the Big Bang. This is unexpected
and counter to many theories of cluster and galaxy formation," says
Macchetto. "Although nothing conclusive can be stated with only
one cluster,  now that we know how to search for them we will be  able
to strongly constrain these theories."
 
Dickinson selected a candidate cluster for Hubble's sharp vision as a result
of a ground-based infrared survey of the environments of distant  radio
galaxies. Based on the color and the statistical distribution of the galaxies,
Dickinson concluded that a cluster is at the same distance as the radio
galaxy 3C 324, located nine billion light-years away in the constellation
Serpens.      The cluster appeared to have a population of very red galaxies
similar in color to  present-day elliptical galaxies.
 
Hubble's 18-hour long exposure reveals thousands of faint galaxies near
the limit of what Hubble can detect (29th magnitude). "Though many are
presumably closer or farther than the cluster, since Hubble  is peering
across a tremendous volume of the universe to reach 3C 324, the galaxies
concentrated around 3C 324 are most likely cluster members,  he reports.
 
 
The Birth of Galaxies
 
Island cities of hundreds of billions of stars each, galaxies allow
astronomers to trace the evolution of matter and structure since the
beginning of the universe in the Big Bang.   Scientists have sought to
understand this evolution ever since American astronomer Edwin
Hubble sorted nearby galaxies into three fundamental shapes: spiral or
disk-shaped, elliptical, and irregular.
 
As the Big Bang theory gained acceptance in the 1950s, astronomers
realized that galaxies simply weren't made the way they appear today
but must evolve over time.  This notion was reinforced by two dramatic
discoveries in the 1960s: the confirmation of the Big Bang by detection
of the cosmic microwave background and the discovery of quasars.
Quasars are theorized to be the active cores of extremely distant galaxies.
Their abundance at great distances clearly shows that galaxies were
at a different evolutionary stage billions of years ago.
 
However, the fainter "normal" population of early galaxies has been
elusive, because the tiny images of distant galaxies smear into faint
blurs when viewed through Earth's atmosphere.  In the late 1970s,
astronomers found the first evidence that the stellar populations of
galaxies had changed dramatically, even over a relatively small fraction
of the time back toward the Big Bang.  Astronomers also were puzzled
by a specie of  blue galaxies in distant clusters, which disappeared in
our current epoch.
 
Now, Hubble Space Telescope's sharp view at last provides for
detailed studies of the properties of  early galaxies.  Hubble's initial
results show that the mysterious blue cluster galaxies are mostly spirals,
often with signs of  disturbance that may provide clues about their
disappearance by the present epoch. Paradoxically, elliptical galaxies
appear normal throughout most of the history of the universe, with
little evidence for dramatic changes in their stellar population or shape.
 
                                       ******
Co-investigators on Alan Dressler's team: Gus Oemler  (Yale); Harvey
Butcher (Netherlands Foundation for Astronomy); Richard Sharples
(Durham University, U.K.), Richard Ellis (Cambridge University,  U.K.),
and Warrick Couch (University of New South Wales, Australia).
 
Co-investigators on Mark Dickinson's team: Hyron Spinrad and
Arjun Dey (U.C. Berkeley), S. Adam Stanford (IPAC/JPL), Peter
Eisenhardt (JPL), George Djorgovski (California Institute of
Technology).
 
Co-investigators on Duccio Macchetto's team: Mauro Giavalisco
(STScI), Charles Steidel (MIT), Piero Madau (STScI), and William
Sparks (STScI).

From: [email protected] (Ron Baalke)
Subject: Hubble Observes a New Saturn Storm
Date: 20 Dec 1994 15:24:36 -0800
Organization: Jet Propulsion Laboratory
 
PHOTO RELEASE NO.:  STScI-PRC94-53 RELEASE DATE:  DECEMBER 21, 1994
 
HUBBLE OBSERVES A NEW SATURN STORM
 
This NASA Hubble Space Telescope image of the ringed planet Saturn 
shows a rare storm that appears as a white arrowhead-shaped feature 
near the planet's equator.  The storm is generated by an upwelling of 
warmer air, similar to a terrestrial thunderhead.  The east-west extent of 
this storm is equal to the diameter of the Earth (about 7,900 miles).  
Hubble provides new details about the effects of Saturn's prevailing 
winds on the storm.  The new image shows that the storm's motion 
and size have changed little since its discovery in September, 1994.
 
The storm was imaged with Hubble's Wide Field Planetary Camera 2 
(WFPC2) in the wide field mode on December 1, 1994, when Saturn 
was 904 million miles from the Earth.  The picture is a composite of 
images taken through different color filters within a 6 minute interval 
to create a "true-color" rendition of the planet.  The blue fringe
on the right limb of the planet is an artifact of image processing 
used to compensate for the rotation of the planet between exposures.
 
The Hubble images are sharp enough to reveal that Saturn's prevailing 
winds shape a dark "wedge" that eats into the western (left) side of the 
bright central cloud.  The planet's strongest eastward winds (clocked at 
1,000 miles per hour from analysis of Voyager spacecraft images taken in 
1980-81) are at the latitude of the wedge.
 
To the north of this arrowhead-shaped feature, the winds decrease so 
that the storm center is moving eastward relative to the local flow.  The 
clouds expanding north of the storm are swept westward by the winds 
at higher latitudes.  The strong winds near the latitude of the dark 
wedge blow over the northern part of the storm, creating a secondary 
disturbance that generates the faint white clouds to the east (right) of 
the storm center.
 
The storm's white clouds are ammonia ice crystals that form when 
an upward flow of warmer gases shoves its way through Saturn's 
frigid cloud tops.  This current storm is larger than the white clouds 
associated with minor storms that have been reported more frequently 
as bright cloud features. 
 
Hubble observed a similar, though larger, storm in September 1990, 
which was one of three major Saturn storms seen over the past two 
centuries.  Although these events were separated by about 57 years 
(approximately 2 Saturnian years) there is yet no explanation why they 
apparently follow a cycle -- occurring when it is summer in Saturn's
northern hemisphere.
 
Credit:   Reta Beebe (New Mexico State University), D. Gilmore, 
L. Bergeron (STScI), and NASA
 
To electronically access this photo release and its associated text, 
you can use ftp or World Wide Web via Internet. The image file is on 
ftp.stsci.edu in the directory /pubinfo/gif:
 
PR#		GIF File	Caption text	Object    
 
STScI-PRC94-53	SatStorm.gif	SatStorm.txt	Saturn with Storm  
 
Another directory, /pubinfo/latest, contains all of the files relevant to 
the latest releases.  The same data is available using  WWW/Mosaic, 
which is always accessible via: http://www.stsci.edu/OPO.html.   
Or you can use:  http://www.stsci.edu/EPA/Latest.html to get right to 
the latest release.
 

Donald Savage
Headquarters, Washington, DC           December 22, 1994
(Phone:  202/358-1547)
 
RELEASE:  C94-oo
 
NASA SELECTS NEXT REPLACEMENT CAMERA FOR HUBBLE TELESCOPE 
 
       NASA Associate Administrator for Space Science, Dr. 
Wesley T. Huntress, Jr.,  announced the selection of a 
proposed scientific investigation which includes the 
development of a new camera for the Hubble Space Telescope 
(HST).  The estimated cost of the new camera is about $30 
million.
 
       NASA will work with Dr. Holland Ford of Johns 
Hopkins University, Baltimore, MD, to negotiate a contract 
for the new camera, called Hubble Advanced Camera for 
Exploration (HACE).  The new camera is planned for 
installation on the HST by Shuttle astronauts during the 
third servicing mission scheduled for November 1999.
 
       The new camera's capabilities will be a major 
enhancement to Hubble's present camera, the Wide Field and 
Planetary Camera-2 (WFPC-2) according to Dr. Edward Weiler, 
HST Program Scientist, Washington, DC.  WFPC-2 was 
installed into the orbiting space telescope by Shuttle 
astronauts during the December 1993 servicing mission.
 
       "HACE not only will maintain but will greatly 
enhance HST's superlative imaging capabilities well into 
the next century," said Weiler.  "It will allow astronomers 
to make even more detailed observations of black holes, 
quasars and galaxies which formed immediately after the Big 
Bang, as well as solar system objects."
 
       Plans call for the HACE to be installed into the HST 
instrument bay in place of one of the current instruments.  
NASA will decide which instrument to replace about two or 
three years before the 1999 mission.  The decision will be 
based on the health and scientific productivity of the 
instrument.
 
       Ball Aerospace Corp., Boulder, CO, is the prime 
hardware contractor for HACE.
 
                   - end -

    See the new issue of "Time" for an interesting controversy started by
    Hubble observations.
    
    Mike

 
Don Savage
Headquarters, Washington, DC               June 6, 1995
(Phone:  202/358-1547)
 
Tammy Jones
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-5566)
 
Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone:  410/338-4514)
 
RELEASE:  95-83
 
HUBBLE OBSERVES THE FIRE AND FURY OF A STELLAR BIRTH
 
     NASA's Hubble Space Telescope has provided a detailed 
look at the fitful, eruptive, and dynamic processes 
accompanying the final stages of a star's "construction." 
 
     Images from the orbiting observatory reveal new 
details that will require further refinement of star 
formation theories, according to several independent teams 
of astronomers who have used Hubble to observe different 
embryonic stars.  The Hubble observations shed new light on 
one of modern astronomy's central questions: how do tenuous 
clouds of interstellar gas and dust make stars like our Sun?
 
     "For the first time we are seeing a newborn star close 
up -- at the scale of  our solar system -- and probing the 
inner workings," said Chris Burrows of the Space Telescope 
Science Institute, Baltimore, MD, and the European Space 
Agency.  "In doing so we will be able to create detailed 
models of star birth and gain a much better understanding 
of the formation of our Sun and planets." 
 
     The Hubble images provide a dramatically clear look at 
a collapsing circumstellar disk of dust and gas that builds 
the star and provides the ingredients for a planetary 
system, blowtorch-like jets of hot gas funneled from deep 
within several embryonic systems, and machine-gun like 
bursts of material fired from the stars at speeds of a 
half-million miles per hour.
 
     The images offer clues to events that occurred in our 
solar system when the Sun was born 4.5 billion years ago.  
Astronomers commonly believe that Earth and the other eight 
planets condensed out of a circumstellar disk because they 
lie in the same plane and orbit the Sun in the same 
direction.  According to this theory, when the Sun ignited 
it blew away the remaining disk, but not before the planets 
had formed.
 
     "The Hubble images are opening up a whole new field of 
stellar research for astronomers and clearing up a decade's 
worth of uncertainty," added Jeff Hester of Arizona State 
University, Tempe, AZ.  "Now we can look so close to a star 
that many details of star birth become clear immediately."
 
     The key new details revealed by the Hubble pictures:
 
     *    Jets originate from the star and the inner parts 
of the disk and become confined to a narrow beam within a 
few billion miles of their source.  It's not known how the 
jets are focused, or collimated.  One theory is that 
magnetic fields, generated by the star or disk, might 
constrain the jets.
 
     *    Stars shoot out clumps of gas that might provide 
insights into the nature of the disk collapsing onto the 
star.  The beaded jet structure is a "ticker tape" 
recording of how clumps of material have, episodically, 
fallen onto the star.  In one case, Hubbleallowed 
astronomers to follow the motion of the blobs and measure 
their velocity.
 
     *    Jets "wiggle" along their multi-trillion-mile 
long paths, suggesting the gaseous fountains change their 
position and direction.  The wiggles may result from the 
gravitational influence of one or more unseen protostellar 
companions.
 
     More generally, Hester emphasizes:  "Disks and jets 
are ubiquitous in the universe.  They occur over a vast 
range of energies and physical scales, in a variety of 
phenomena."  Gaining an understanding of these young 
circumstellar structures might shed light on similar 
activity in a wide array of astronomical phenomena:  novae, 
black holes, radio galaxies and quasars.
 
     "The Hubble pictures appear to exclude whole classes 
of models regarding jet formation and evolution," said Jon 
Morse of the Space Telescope Science Institute.
 
     A disk appears to be a natural outcome when a slowly 
rotating cloud of gas collapses under the force of gravity 
-- whether the gas is collapsing to form a star, or is 
falling onto a massive black hole.
 
     Material falling onto the star creates a jet when some 
of it is heated and blasted along a path that follows the 
star's rotation axis, like an axle through a wheel. 
 
     Jets may assist star formation by carrying away excess 
angular momentum that otherwise would prevent material from 
reaching the star.  Jets also provide astronomers with a 
unique glimpse of the inner workings of the star and disk.  
"Not even the Hubble Telescope can watch as material makes 
its final plunge onto the surface of the forming star, but 
the new observations are still telling us much about that 
process," said Hester.
 
     Burrows, Hester, Morse and their co-investigators 
independently observed several star birth sites in our 
galactic neighborhood.  "All of these objects tell much the 
same story," Hester emphasized.  "We are clearly seeing a 
process that is a crucial part of star formation, and not 
just the peculiarities of a few oddball objects."
 
     The researchers all agree that the Hubble pictures 
generally confirm models of star formation but will send 
theorists back to the drawing board to explain the details.  
The researchers emphasize that future models of star 
formation will have to take into account why jets are 
ejected from such a well-defined region in the disk, why 
jets are collimated a few billion miles out from the star, 
and why gas in the jets is ejected quasi-periodically.
 
			- end -
 
EDITOR'S NOTE:  Images to illustrate this release are 
available for news media representatives by calling the 
Headquarters Broadcast and Imaging Branch on 202/358-1900.  
Photo numbers are:
 
Caption description                      Color           B&W
Hubble Views of Three Stellar Jets     95-HC-292       95-H-297
Motion Of Jets From An Embryonic Star                  95-H-298
Pair of Jets from a Young Star         95-HC-293       95-H-299
Wiggling Jet from a Wobbling Star                      95-H-300
 
Image files in GIF and JPEG format may be accessed on 
Internet via anonymous ftp from ftp.stsci.edu in the 
/pubinfo directory:
 
                                    GIF          JPEG
 
PRC95-24a      HH30/HH34/HH47   gif/JetDisk3 jpeg/JetDisk3
PRC95-24b      HH30 Jet Motion  gif/HH30     jpeg/HH30
PRC95-24c      HH1/HH2 Details  gif/HH1-2    jpeg/HH1-2
PRC95-24d      HH47 Jet Detail  gif/HH47     jpeg/HH47
 
 
 
The same images are available via World Wide Web from these 
URL locations: http://www.stsci.edu/pubinfo/PR/95/24.html, 
or via links in http://www.stsci.edu/public.html.