Conference 7.286::space

Date: Thu, 16 Mar 89 09:37:41 PST
From: Peter Scott <[email protected]>
Subject: Voyager update
X-Vms-Mail-To: EXOS%"[email protected]"
 
    Excerpted without permission from NASA Voyager Bulletin, Mission Status 
Report # 85, March 3, 1989 [stuff in square brackets is Peter Scott's]: 
 
    It's not just a fuzzy tennis ball after all...
    ----------------------------------------------
 
    A bright cloud feature on Neptune, similar to spots seen by
planetary astronomers using Earth-based telescopes, is visible in
images taken by Voyager 2 on January 23, 1989 when the spacecraft was
about 309 million kilometers (185 million miles) from the planet.  The
fact that distinct cloud features are visible while the spacecraft is
still so distant suggests that pictures taken as Voyager 2 approaches
its August 1989 flyby of Neptune will show far more detail than was
visible in the atmosphere of Uranus, which Voyager 2 encountered in
January 1986.  (Due to the lack of visible cloud features, Uranus has
been lightheartedly described as a "fuzzy blue tennis ball," and less
kindly as bland.) 
 
    The cloud is at about 30 degrees south latitude, and its motion
during the time between images is consistent with the 17- to 18-hour
rotation period derived from observations with Earth-based telescopes.
The January images show details as small as about 6000 kilometers
(3500 miles).  The cloud has not yet been confirmed to be any of the
cloud features seen on Neptune by Drs. Richard Terrile of JPL and Brad
Smith of the University of Arizona at Las Campanas Observatory, Chile,
in 1983, or by Dr. Heidi Hammel of JPL at the University of Hawaii's
Mauna Kea facility in 1988.  The features seen from these Earth-based
telescopes were best seen through methane filters not available on
Voyager 2, and imaging scientists have been somewhat concerned that
such features might not be visible to Voyager 2's cameras. 
 
    The mottled appearance of Neptune in these frames is likely to be
"noise" in the camera system.  Color versions of these images, assembled 
from pictures taken through violet, clear, and orange filters, show a 
dark band of clouds encircling the planet's southern pole.  [...]  The 
natural color of Neptune is a pale blue-green, caused by the absorption 
of red light by methane gas in the planet's atmosphere. 
 
    [...] Spacecraft review
          -----------------
 
    [...] At launch, each spacecraft carried about 105 kilograms (232
pounds) of hydrazine.  During its 11.5 years in space, Voyager 2 has
used about 60 kilograms (140 pounds) of hydrazine. 
 
    [...] Each Voyager is powered by three radioisotopic
thermoelectric generators (RTGs), which produce electrical energy
throutgh the conversion of heat generated by the radioactive decay of
plutonium-238.  At launch, the power output of the RTGs was about 423
watts.  The power output steadily declines as the plutonium decays,
and is now about 380 watts.  The science instruments require about 105
watts, or about the same wattage as a typical light bulb. 
 
    [...]  Instrument Description and Health
           ---------------------------------
 
    [...] Each Voyager spacecraft carries two imaging cameras: a
200-mm, f/3.5 wide-angle camera using a refracting telescope and a
1500-mm f/8.5 narrow-angle (telephoto) camera using a reflecting
telescope.  Each camera carries a one-inch selenium-sulfur vidicon to
convert an optical scene into electrical signals. 
 
    Each frame consists of 640,000 pixels, each of which is expressed
as a level of gray on a scale from 0 (black) to 255 (white).  [...] 
The sensitivity of the filters ranges from 3460 (ultraviolet) to 6184
angstroms (red-orange). [...] 
 
    Voyager 2's narrow-angle camera has dust specks on the vidicon
which result in faint, doughnut-shaped blemishes in images [what do
they expect, it's been twelve years since the maid came].  In
addition, the emission of the vidicon cathode in the narrow-angle
camera has decreased since launch. 
 
    [...]  The photopolarimeter measures the way light is scattered
from particles in an atmosphere or on a surface.  By studying the
polarization of reflected light as ther lighting geometry changes
during a flyby, scientists can make inferences about the nature of a
planetary surface or atmosphere.  The photopolarimeter can also be
used to study rings by measuring the intensity of a background star as
the starlight passes through the rings. 
 
    The photopolarimeter consists of a 200-mm Cassegrain telescope
with filters, polarization analyzers, and a photomultiplier tube to
convert incoming light into electronic signals.  It covers three
wavelengths in the region between 265 and 750 millimicrons.  Five of
the eight original filters and four of the eight original analyzers
are no longer accessible.  [...] 
 
    Voyager 2's Health
    ------------------
 
    Both Voyagers have experienced several health problems since
launch, some minor and some rather major ones.  Nevertheless, mission
controllers have in every case been able to identify the problems and
provide a way to continue to meet mission objectives. 
 
    In September 1977, about a month after launch, Voyager 2 suffered
a hardware failure in the FDS [flight data subsystem - one of the
computers].  As a result, 15 engineering measurements can no longer be
made (about 215 engineering measurements remain). 
 
    In 1978, eight months after launch, Voyager 2's main radio
receiver failed, and a tracking loop capacitor failed in the backup
receiver.  As a result, Voyager 2 can receive signals in only a narrow
"window" of frequencies--and the window slides.  The window is about
1000 times narrower than it originally was, and temperature changes in
the radio receiver of even 1/4 degree cause the window to slide up or
down in frequency.  Temperature changes can be caused by heat
generated by the spacecraft's electronics.  The flight team has
devised a rigorous routine for commanding the spacecraft.  Signals are
sent several times at different frequencies to determine the receiver's 
current frequency "window".  Commands are then transmitted, after 
calculating where the receiver's "window" will be, and taking into 
account how the signal frequency will change due to Earth's rotation 
and other motions. 
 
    [...]  In August 1981, just after Voyager 2 passed Saturn, the
scan platform quit moving.  Three years of intensive analysis and
testing of similar parts on Earth, and of the scan platform on Voyager
1, led to a failure model and to guidelines for safe usage of the
platform.  The failure has been attributed to a lack of full
lubrication of the bearing area between the gear and pin in the
azimuth actuator.  Lubricant has probably migrated back to the bearing
surfaces, healing the problem.  Adherence to the guidelines for safe
usage permitted Voyager to complete a successful encounter with Uranus
in 1986, returning some of the highest resolution images ever taken of
solar system bodies.  [...] 
 
    Just days before its closest approach to Uranus, Voyager 2
suffered the loss of one word of memory in one FDS processor.  As a
result, bright and dark streaks appeared in images.  Only imaging data
was affected, and a software patch was sent to bypass the failed bit. 
 
    Despite a little arthritis, a little hearing problem, and some
loss of memory, Voyager 2 is still in excellent operating condition,
and gaining rapidly on Neptune and Triton. 
 
    Peter Scott ([email protected])
 

Hi,

Can anyone answer any or all of the following?

	What happened Voyager 1 ?
	Is there a PIONEER craft that is "further" from Earth than
	the Voyagers?
	What sort of Hardware (MSI?) is on the Voyager?
	Does the USSR have an equivalent?

Thanks in advance
John

    	VOYAGER 1 is still functioning, and will probably continue to do 
    so through the year 2000.  It is now heading above the plane of the
    ecliptic (the plane is where the planets orbit the Sun), and will
    encounter no more planets (at least in this solar system).  It is
    expected to last roughly one billion years in interstellar space, and
    will come within a few lightyears of several stars on its journey
    through the Milky Way Galaxy.  
    
    	The same events will also occur for VOYAGER 2 and PIONEER 10 and 11,
    both of which are far ahead of the VOYAGERs, having been launched in
    1972 and 1973 (the VOYAGERS were launched in 1977).  Both types of
    probes have messages for any intelligences (alien or our future star-
    traveling descendants) which happen to find the craft.  The PIONEERs
    carry plaques, and the VOYAGERs have records of Earth life, sounds, 
    and music.  Details on these messages can be found in Carl Sagan's
    1978 book, MURMURS OF EARTH (Random House).
    
    	Though I'm not sure exactly what type of computers are aboard the
    VOYAGERs, I have read that they are more primitive than today's home
    personal computers.
    
    	No, the Soviets have not launched any probes to any celestial
    objects beyond Venus, Mars, and Comet Halley.
    
    	Larry
    

    	For more on the current state of the PIONEER probes, see Topic 435.
    

    Re: .2
    	Well I can answer 3 of the 4 questions:
    
    1) Voyager 1 is still being tracked and is still making periodic
    measurements of the interplanetary conditions (e.g. B-fields, particle
    fluxes, etc.)
    
    2) Pioneer 10 and Pioneer 11 are further out than either Voyager
    spacecraft. This situation should change around the turn of the century.
    The Voyagers (especially V 2) are exiting the solar system faster
    than the Pioneers did and the Pioneers should be passed sometime
    in the next 10 years or so (I forget the exact figures)
    
    3) MSI??
    
    4)The Soviets have no spacecraft that have reached much beyond
    the orbit of Mars. There were some rumors of a "Yupiter" spacecraft
    to be sent to Jupiter in the early 80's but it was only a rumor.
    There are now plans (not yet approved) for a Saturn/Titan mission 
    in 1998. But there are apparently no plans for any Soviet spacecraft
    to exit the solar system. As has been proven many times in the past
    (most recently with the Phobos mission) the Soviets have spacecraft
    reliability problems that make an successful outer planet mission
    unlikely.
    
    			Drew
    

    Re: .5
    
    MSI - Medium Scale Integration - an indication of the number of
    transistors crammed onto a chip.
    
    Gregg

Guys, I REALLY appreciate the answers,

However, I'm going for broke with two more quickies!!!

	Do the pictures of Saturn, Jupiter... we see on the TV screens show
	natural colours of the planets, or computer generated colours ?

	Any books (or official releases) of these photos?

Thanks again in advance!!

John

    write JPL in Cal, when I ask them about the mission they
    sent me about 50 color slides.  Also call or write  the Sup. of Documents
    at US Gvt Printing office ,  Washington DC 70402
    202-783 3238 
    or if in the Boston Mass area 617 6071.  Ask for a catalog 
    of Space and Science, they may have the print such a book.  
    I know the have all the photo of Mars and maps made up of
    the photos...
    
    john
    

    re: .7
    	The photos that are generally seen from almost any planetary
    probe are not in natural color. This is primarily for two reasons:
    
    1) The filters used on the cameras generally do not match the primary
    colors detected by the eye (i.e. red, green, and blue). As an example,
    Voyager frequently uses orange, clear, and violet filters to construct
    "color" photos (among other combinations).
    
    2) Even when the filtered images match or are processed to approximate
    the primary colored components of a scene, usually the resulting
    picture presents only limited information to the scientist or are
    just plain dull looking to the public. In order to get the maximum
    amount of information out of the photo or to make it more appealling
    to the eye, the pictures have the saturation of the colors and the
    contrast stretched. A classic example is Jupiter's moon Io which
    in most photos looks primarily red or orange. If you were to travel
    there yourself and look at Io it would look more like a washed out
    yellowish orange quite different than the typical photo. 
    
    	From a man with many years of image processing experience,
                                   Drew
    

	For the cost of a tape you can get the Voyager images in an 
	electronic form from NASA (if you ask nicely !!).

	As a previous note mentioned each image comes as an 800 x 800
	pixel image, with each pixel taking a value from 0 to 255.

	Colour images are made up to a series of images and consequently 
	there are fine differences in the images which made up the colour
	image. This can be seen around the edge of the planet in the picture
	as "fuzziness".

	Unfortunatly, on your average LJ250 this is the least of your 
	problems.

    
    	Are any of these images available over the net ?
    
    	_Brij

    

>    	Are any of these images available over the net ?


	SNOC01""::DISK$CC60J:[IMAGE]

Sorry to be ignorant but how can I TYPE/PRINT

		SNOC01""::DISK$CC60J:[IMAGE]

John

    You can't - you have to translate the image data into something
    which you CAN print (sixel format, for example).  There's a file
    in the same area called "INFO.DOC" which gives the format of the
    image data file.
    
    I'm screwing around with a C program to do the translation; if
    I ever get it completed I'll make it available.

	Sorry for not being more specific.

	The files I have placed in the directory SNOC01::DISK$CC60J:[IMAGE]
	are the following.

	INFO.DOC

		Some notes on the Voyager image file and how to read the
		data into a program. It also describes the programs 
		contained in this directory.

	SIXEL_IMAGE_FILE.DAT

		This is a sixel file of the image that has been generated by 
		the program listed. (ie VOYAGER_IMAGE.PAS)

		It is designed to be printed on an LJ250, in strips to 
		fit onto an 80 column wide paper.

		This file can be typed on any sixel supported terminal (eg
		VT330, VT340). However this is not particularly useful as
		the image is a good deal larger than the screen, so all
		you see is the left-hand side of the image.


	SIXEL_REF.PAS

		A PASCAL program to produce a file containing a 6 character
		sixel string for each pixel value from 0 to 255.

		eg 	255  '??????'	This sixel char string will produce
					a white 6 x 6 dot.
                          .	.
                          .	.
                          .	.

			  0  '~~~~~~'   This sixel char string will produce
					a black 6 x 6 dot.


		This output file is used by VOYAGER_IMAGE to generate the
		sixel_image_file.


	VOYAGER_298_1.DAT

		The image data file obtained from NASA.

		The format of the file is describe (in brief) in the file
		INFO.DOC.


	VOYAGER_IMAGE.PAS

		A PASCAL program that generates the sixel_image_file
		you can either generate the image in 4 strips or as
		a single image. The 4 strip version is for 80 column
		paper printers and the single image is for laser 
		printers (ie LN03+, LPS40)



	If you have any problems, comments, suggestions on any of this
	my VAXmail address is SNOC01::NORMAN

	
	Russell.

    VOYAGER STATUS - can890408.txt - 4/3/89 
 
    Editor's note: The following information is taken from the March
22 status report for the Voyager 2 spacecraft. 
  
    A bright cloud feature on Neptune, similar to spots seen by
planetary astronomers using Earth-based telescopes, is visible in
images taken by Voyager 2 on January 23, 1989, when the spacecraft was
about 309 million kilometers from the planet. The fact that distinct
cloud features are visible while the spacecraft is still so distant
suggests that pictures taken as Voyager 2 approaches its August 1989
flyby of Neptune will show many more features than were visible in the
atmosphere of Uranus, which Voyager 2 encountered in January 1986.
(Due to the lack of visible cloud features, Uranus has been
lightheartedly described as a "fuzzy blue tennis ball," and less
kindly as bland.) 
 
    The cloud is at about 30 degrees south latitude, and its motion
during the time between images is consistent with the 17- to 18- hour
rotation period derived from observations with Earth-based telescopes.
The January images show details as small as about 6000 kilometers. The
cloud has not yet been confirmed to be any of the cloud features seen
on Neptune by Richard Terrile of JPL and Brad Smith of the University
of Arizona at Las Campanas Observatory, Chile, in 1983, or by Heidi
Hammel of JPL at the University of Hawaii's Mauna Kea facility in
1988. The features seen from these Earth-based telescopes were best
seen through filters that pass the spectral characteristics of
methane. Filters at this wavelength band are not available on Voyager
2, and imaging scientists had been somewhat concerned that such
features might not be visible to Voyager 2's cameras. 
 
    The mottled appearance of Neptune in these frames is likely to be
"noise" in the camera system. Color versions of these images,
assembled from pictures taken through violet, clear, and orange
filters, show a dark band of clouds encircling the planet's southern
pole. The banded appearance is similar to cloud structures on the
three other giant planets, Jupiter, Saturn, and Uranus. The natural
color of Neptun is a pale blue-green, caused by the absorption of red
light by methane gas in the planet's atmosphere. 
 
    Spacecraft Review and Status
 
    Both Voyager spacecraft have survived in space for nearly 12
years, and although each has experienced some hardware failures, they
are still in robust health and capable of returning valuable
scientific data well into the next century. 
 
    Spacecraft Review
 
    The core of each Voyager is a 10-sided bus, an aluminum framework
ring which houses the spacecraft's electronics. The bus is about 50 cm
high and 180 centimeters across. 
 
    Each spacecraft carries three computer subsystems: the computer
command subsystem (CCS), the flight data subsystem (FDS), and the
attitude and articulation control subsystem (AACS). Each computer has
a backup, for a total of six computers, each with a separate memory. 
 
    The CCS is in overall control of the spacecraft. It monitors
spacecraft activities, routes commands back and forth between the
other computers, receives commands from Earth, and issues commands to
send data back to Earth. 
 
    Computer programs (called sequence loads) to control the
spacecraft are written on Earth and transmitted to the CCS. During
cruise phases, a sequence load may operate the spacecraft for as long
as six months; during a planetary encounter, a sequence load may
operate the spacecraft for as few as 50 hours, depending on the
complexity of the activities required to obtain the science data at
the planet. A sequence load for a relatively quiet cruise phase may
take about nine weeks to plan, build, and test before it is sent to
the spacecraft, while an encounter load may take as long as 15 months.
 
    Seven fault detection and correction routines are stored in the
CCS at all times to automatically place the spacecraft in a safe state
should the CCS detect a problem, such as an electrical short, a
receiver or transmitter failure, or a failure in the CCS. 
 
    The FDS collects engineering and science data measurements and
formats the data for transmission to Earth. The FDS controls the
science instruments as directed by the CCS. The FDS also has several
special data handling modes, such as data compression and encoding. 
 
    Data are often recorded on board the spacecraft on a high-
capacity eight-track digital tape recorder for transmission to Earth
at a later, more convenient time. For example, mission controllers may
opt to wait until the spacecraft is "over" a specific DSN station
before asking the spacecraft to transmit its data to Earth. Similarly,
data is recorded during high-activity periods, or when the spacecraft
is behind a planet. 
 
    The AACS maintains the pointing of the spacecraft's antenna,
orients or maneuvers the spacecraft, and points (articulates) the scan
platform. The spacecraft is stabilized on three axes (pitch, yaw, and
roll) and senses its orientation either through its internal
gyroscopes, or by tracking two celestial bodies, typically the Sun and
a reference star such as Canopus). The AACS maintains the spacecraft's
orientation by using small rocket thrusters which expel hydrazine
propellant, a compound of nitrogen and hydrogen. At launch, each
spacecraft carried about 105 kilograms of hydrazine. During its 11-1/2
years in space, Voyager 2 has used about 60 kilograms of hydrazine. 
 
    The Voyagers communicate with Earth via their telecommunications
systems, which include a 3.65-meter-diameter high-gain antenna, a
low-gain antenna, an S-band receiver, and X- and S-band transmitters.
The spacecraft can receive only in the S-band frequencies, at about
2100 MHz. They can transmit both at S-band (about 2300 MHz) and at
X-band (about 8400 MHz). The X-band frequency has a narrower beamwidth
and thus a tighter focus than does the S-band. The wavelength of the
X-band signal is 3.5 cm, while the wavelength of the S-band signal is
slightly longer at 13 cm. 
 
    Each Voyager is powered by three radioisotope thermoelectric
generators (RTGs), which produce electrical energy through the
conversion of heat generated by the radioactive decay of
plutonium-238. At launch, the power output of the RTGs was about 423
watts. The power output steadily declines as the plutonium decays, and
is now about 380 watts. The science instruments require about 105 watts. 
 
    Instrument Descriptions and Health
 
    Each spacecraft carries instruments for ten scientific
investigations. Optical instruments for four of the investigations are
mounted on a movable (scan) platform at the end of a short boom.
Instruments for six more investigations measure magnetic and
electrical fields and charged or neutral particles in space and in the
vicinity of planets. In addition, the spacecraft radio is used for an
eleventh investigation. 
 
    Scan Platform Instruments
 
    Imaging Cameras (ISS): Each Voyager spacecraft carries two imaging
cameras: a 200-mm, f/3.5 wide-angle camera using a refracting
telescope and a 1500-mm f/8.5 narrow-angle (telephoto) camera using a
reflecting telescope. Each camera uses a one-inch selenium-sulfur
vidicon to convert an optical scene into electrical signals. Each
frame consists of 640,000 picture elements (pixels), each of which is
expressed as a level of grey on a scale from 0 (black) to 255 (white).
Color scenes are reconstructed on Earth by electronically combining
images taken through different filters. The sensitivity of the filters
ranges from 3460 (ultraviolet) to 6184 angstroms (red-orange). (The
human eye can see in the range from 4000 to 7000 angstroms.) 
 
    Voyager 2's narrow-angle camera has dust specks on the vidicon
which result in faint, doughnut-shaped blemishes in images. In
addition, the emission of the vidicon cathode in the narrow-angle
camera has decreased since launch. 
 
    Imaging team leader is Bradford A. Smith of the University of
Arizona, Tucson, Arizona; deputy team leader is Larry A. Soderblom of
the U.S. Geological Survey, Flagstaff, Arizona. 
 
    Photopolarimeter (PPS): The photopolarimeter measures the way
light is scattered from particles in an atmosphere or on a surface. By
studying the polarization of reflected light as the lighting geometry
changes during a flyby, scientists can make inferences about the
nature of a planetary surface or atmosphere. The photopolarimeter can
also be used to study rings by measuring the intensity of a background
star as the starlight passes through the rings. 
 
    The photopolarimeter consists of a 200-mm Cassegrain telescope
with filters, poarization analyzers, and a photomultiplier tube to
convert incoming light into electronic signals. It covers three
wavelengths in the region between 265 and 750 millimicrons. Five of
the eight original filters and four of the eight original analyzers
are no longer accessible. 
 
    Principal investigator is Lonne Lane of the Jet Propulsion Laboratory,
Pasadena, California.
 
    Infrared interferometer spectrometer and radiometer (IRIS): IRIS
measures the temperatures of planets and satellites to determine their
energy balance (the balance between the heat received from the Sun and
the heat--if any--generated by the body itself). Global temperature
maps are produced for each body. IRIS also studies the molecular
composition of atmospheres, and can detect molecules such as hydrogen,
ammonia, methane, ethane, acetylene, and other complex hydrocarbons.
IRIS uses a 50-cm telescope to gather light and direct it into the
optics. The radiometer measures the solar radiation reflected from a
body in the range from 0.3 to 2.0 microns, while the interferometer
measures radiation emitted in the middle-and far-infrared (4.0 to 55
microns). The neon reference signal has decreased, and the
interferometer has lost some of its sensitivity due to degraded
alignment of its optical components. 
 
    Principal investigator is Barney J. Conrath of NASA's Goddard
Space Flight Center in Greenbelt, Maryland. 
 
    Ultraviolet spectrometer (UVS): The ultraviolet spectrometer
studies the chemical composition, temperature, and structure of
atmospheres by observing how ultraviolet light from the Sun is
absorbed or scattered after it enters the atmosphere of a planet or
satellite. It also studies ultraviolet light coming from stars. 
 
    The UVS detects and measures ultraviolet radiation in the range
from 500 to 1700 Angstroms.  Included in this range are the atomic
hydrogen Lyman alpha series, molecular hydrogen, helium, methane
(natural gas), acetylene, ethane, and other atmospheric hydrocarbons. 
 
    Principal investigator is A. Lyle Broadfoot of the University 
of Arizona, Tucson, Arizona.
 
    Radio Science
 
    Effects on Voyager's radio signals can help determine the
structure and composition of  an atmosphere, the size and distribution
of particles in rings, and the characteristics of planetary and
satellite gravitational fields. 
 
    Team leader is Len Tyler of Stanford University's Center for Radar
Astronomy, Stanford, California. 
 
    Fields & Particles Instruments
 
    Magnetometers (MAG): Each Voyager carries four magnetometers
mounted along a 13-meter boom. The magnetometers help characterize
planetary magnetic fields, as well as the structure of a magnetosphere
and its interactions with planetary moons. Interplanetary magnetic
fields are also measured. 
 
    The dynamic range of the low-field magnetometers is from about 0
to 50,000 gammas, while the range of the high-field magnetometers is
from about 1/2 to 20 gauss (50,000 to 2 million gammas). 
 
    Principal investigator is Norman F. Ness of the University of
Delaware's Bartol Research Institute, Newark, Delaware. 
 
    Plasma (PLS): Plasmas are hot ionized gases that flow like liquids
and are affected by magnetic fields. Plasmas are often trapped by
planetary magnetic fields and interact with planetary satellites and
rings. The plasma detector characterizes these interactions and also
determines the properties and radial evolution of the solar wind. PWS
measures protons and electrons in the energy range from 10 to 5950
electron volts and ions from 20 to 11,900 electron volts. 
 
    Principal investigator is John W. Belcher of the Massachusetts
Institute of Technology's Center for Space Research, Cambridge,
Massachusetts. 
 
    Low-Energy Charged Particles (LECP): The LECP instrument measures
the composition and energy spectrum of low-energy charged particles
trapped in planetary magnetospheres, as well as the distribution and
variation of galactic cosmic rays. The instrument measures electrons
in the range from about 15,000 electron volts (15 keV) to more than 11
MeV, and protons and heavier ions in the range from 20 keV to 150 MeV,
as well as nuclei in the range from about 47 keV to more than 200 MeV
per nucleon. The sensitivity of the LECP has decreased slightly over
the years. 
 
    Principal investigator is S. M. (Tom) Krimigis of the Johns Hopkins 
University's Applied Physics Laboratory in Laurel, Maryland.
 
    Cosmic Rays (CRS): Cosmic rays are the most energetic particles
found in nature and are atomic nuclei (primarily protons) and
electrons. Voyager's cosmic ray package uses seven telescopes to
analyze cosmic-ray nuclei ranging from hydrogen through iron, over an
energy range from about 1 to 500 MeV. Principal investigator is Edward
C. Stone of the California Institute of Technology, Pasadena, California. 
 
    Planetary Radio Astronomy (PRA): Radio emissions from planets are
generated by charged particles spiraling along magnetic field lines.
Since the magnetic field originates in the interior of a planet, the
radio emissions are a good indication of processes within the planet.
Radio emissions from the Sun and from lightning in a planet's
atmosphere can also be detected. The planetary radio astronomy
experiment uses two 10-meter whip antennas to listen for planetary
radio emissions over a range from 1.2 kHz to 40.5 MHz. The PRA has
occasional, seemingly random power problems which the spacecraft is
now programmed to sense and automatically correct. 
 
    Principal investigator is James W. Warwick of Radiophysics, Inc.,
Boulder, Colorado. 
 
    Plasma Waves (PWS): Plasma waves are low-frequency oscillations in
the plasmas in interplanetary space and in planetary magnetospheres.
The plasma wave instrument detects and measures plasma wave
interactions in planetary magnetospheres and detects interactions
between a planetary magnetosphere and the solar wind. It can detect
particles in the ring plane and measure their impact rate on the
spacecraft. The PWS shares the two whip antennas with the PRA
investigation to provide the equivalent of a single 7-meter antenna.
PWS covers the frequency range from 10 Hz to 56.2 kHz. 
 
    Principal investigator is Donald Gurnett of the University of 
Iowa, Iowa City, Iowa.
 
    Voyager 2's Health 
 
    Both Voyagers have experienced several health pblems since launch,
some minor and some rather major ones. Nonetheless, mission
controllers have in every case been able to identify the problems and
provide a way to continue to meet mission objectives. 
 
    In September 1977, about a month after launch, Voyager 2 suffered
a hardware failure in the FDS.  As a result, 15 engineering measurements 
can no longer be made (about 215 engineering measurements remain). 
 
    In 1978, eight months after launch, Voyager 2's main radio
receiver failed, and a tracking loop capacitor failed in the backup
receiver. As a result, Voyager 2 can receive signals in only a narrow
"window" of frequencies -- and the window slides. The window is about
1000 times narrower than it originally was, and temperature changes in
the radio receiver of even 1/4 degree cause the window to slide up or
down in frequency. Temperature changes can be caused by heat generated
by the spacecraft's electronics. The flight team has devised a
rigorous routine for commanding the spacecraft. Signals are sent
several times at different frequencies to determine the receiver's
current frequency "window". Commands are then transmitted, after
calculating where the receiver's "window" will be, and taking into
account how the signal frequency will change due to Earth's rotation 
and other motions. 
 
    The receiver problem occurred nearly a year before Voyager 2
reached its first objective, the Jupiter system, yet successful
encounters of Jupiter, Saturn, and Uranus followed. 
 
    In August 1981, just after Voyager 2 passed Saturn, the scan
platform quit moving. Three years of intensive analysis and testing of
similar parts on Earth, and of the scan platform on Voyager 1, led to
a failure model and to guidelines for safe usage of the platform. The
failure has been attributed to a lack of full lubrication of the
bearing area between the gear and pin in the azimuth actuator.
Lubricant has probably migrated back to the bearing surfaces, healing
the problem. Adherence to the guidelines for safe usage permitted
Voyager to complete a successful encounter with Uranus in 1986,
returning some of the highest resolution images ever taken of solar
system bodies. The scan platform was programmed to track the target
body during certain exposures. 
 
    The Uranus encounter was not without its surprises, either. Just
days before its closest approach to Uranus, Voyager 2 suffered the
loss of one word of memory in one FDS processor. As a result, bright
and dark streaks appeared in images. Only imaging data was affected,
and a software patch was sent to bypass the failed bit. 
 
    Despite a little arthritis, a little hearing problem, and some
loss of memory, is still in excellent operating condition, and gaining
rapidly on Neptune and Triton. 
 

Newsgroups: sci.space
Subject: NASA Select TV to feature Voyager 2 Neptune images (Forwarded)
Date: 8 Jun 89 20:02:33 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond
Headquarters, Washington, D.C.
 
Robert MacMillin
Jet Propulsion Laboratory, Pasadena, Calif.
 
    N89-46
    EDITORS NOTE:  NASA SELECT TV TO FEATURE VOYAGER 2 NEPTUNE IMAGES
 
     Beginning Tuesday, June 13, at noon EDT, a selection from the
previous week's images of Neptune from the Voyager 2 spacecraft will
be broadcast on the NASA Select TV system, Satcom F2R, transponder 13,
every Tuesday through Aug. 8. 
 
     The broadcast of the images is expected to last about 1 hour and
will show a replay of the first-order reconstruction of the Voyager's
imaging system views of Neptune.  At the time of the first broadcast,
Voyager 2 will be nearly 2-2/3 billion miles from Earth and
approximately 71 million miles from Neptune. 
 
     On June 5, the Voyager 2 spacecraft went into the observatory
phase mode.  In this mode the spacecraft begins a series of near-
daily imaging observations of Neptune from afar.  Voyager planetary
scientists will use these images to help study the Neptune atmos-
phere, already seen to be more turbulent than that of Uranus and
possessing what appear to be variable "white" spots, covering portions
of whole hemispheres.   The spots come and go with relative rapidity. 
Dr. Brad Smith, University of Arizona, said, "Neptune is now more
interesting that Uranus was even at close encounter."  Smith is the
Voyager Imaging Team leader. 
 
     The observatory phase runs from now through Aug. 6, when the
scientific team goes into the "far encounter" phase.  Voyager's
closest approach to Neptune, the "near encounter" phase, begins near
midnight on Aug. 24.  At this point, the spacecraft will whisk past
Neptune's cloud tops at an altitude of only about 3,000 miles, travelling 
at a velocity relative to Neptune in excess of 37,000 miles per hour. 
 
     The Voyager 2 spacecraft, along with its sister Voyager 1, were
launched on Titan-Centaur vehicles in 1977 by NASA from the Kennedy
Space Center, Fla., to take advantage of a rare (once every 175 years)
planetary alignment of Jupiter, Saturn, Uranus and Neptune.  This
alignment allowed NASA's Jet Propulsion Laboratory (JPL), Pasadena,
Calif., to swing both Voyager 1 and 2 from Jupiter to Saturn and, in
the case of Voyager 2, from Saturn to Uranus and on to Neptune. 
 
     Without the advantage of gravity-assist trajectory maneuvers,
neither spacecraft would have been able to encounter more than a
single planet. 
 
     The timetable for NASA Select replay of Voyager 2 images, along
with the distance remaining to Neptune and the distance from Earth, is
given below. 
 
Date             Neptune Distance             Earth Distance
 
June 13          70.70 million miles          2.65 billion miles
June 20          64.40 million miles          2.65 billion miles
June 27          59.00 million miles          2.66 billion miles
*July 4          53.73 million miles          2.66 billion miles
July 11          48.30 million miles          2.664 billion miles
July 18          42.88 million miles          2.67 billion miles
July 25          37.45 million miles          2.678 billion miles
August 1         32.03 million miles          2.686 billion miles
August 8         26.60 million miles          2.696 billion miles
 
    *(This date may move later in the week due to holiday observance.)
 
     The images to be replayed on NASA Select will include both the
actual image of Neptune as seen by Voyager and engineering and science
information about the conditions of the imaging system and lighting
conditions.  This data will appear alongside each image of
retransmissions but will be removed in later, more processed views.
Early transmissions will not show a great amount of detail and the
planet will occupy only a small portion of the imaging frame. Detail
will improve dramatically as the spacecraft nears Neptune. 
 
     One-way light and radio transmission times between the Voyager 2
spacecraft and the NASA Deep Space Network receiver facilities at
Madrid, Canberra and Goldstone, Calif., range from 3 hours, 57 minutes
now to an expected 4 hours, 6 minutes at the closest approach.  It
takes over 8 hours for commands, sent from JPL's Space Flight
Operations Facility, Pasadena, to reach the Voyager 2 spacecraft and
be verified and sent back to Earth. 
 
     Because the JPL facilities associated with the Voyager project
are not completely geared up for the close encounter activity, these
views will be released in video format via satellite only. There will
be no capability to release individual still photos for the complete
video series.  Current expectations, though, include the capability to
release on a periodic basis, a set of hard copy views which have
received the benefit of further computer enhancement.  JPL's complete
computer processing capabilities will be up and running, though, for
the encounter period from Aug. 21 through Aug. 29.  Post encounter
runs from Aug. 29 through Sept. 11, at which time the Voyager 2 will
return to interplanetary cruise mode. 
 
     NASA will operate a full-time Voyager encounter news facility at
the JPL Von Karman Auditorium from Aug. 21 through Aug. 29. 

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Neptune animation
Date: 9 Jun 89 00:19:46 GMT
Organization: The Internet
 
    The NAIF (Navigation Ancillary Information Facility) people here
have a little animation running on a Ramtek of the rotation of Neptune
(just under half a rotation).  You can clearly see the big spot at
about 20 deg south, and there appears to be a smaller white spot
attached to it on the south side.  The only banding visible is a broad
slightly darker band from around 70 to 80 deg south.  Too early to
tell whether mottling on the rest of the planet is noise in the system. 
 
    Peter Scott ([email protected])

    On NPR this AM (20 JUN Tue) they said that Voyager had
    imaged a large storm on Neptune, has anyone heard any
    more about it....  has this image shown up on NASASELECT
    
    jb
    

    	Yes, it is a large black atmospheric phenomenon roughly similar
    to Jupiter's Great Red Spot.  Neptune's "spot" is about 6,000 miles
    in diameter, almost the diameter of Earth (Jupiter's Red Spot is
    the length of three Earths).  Neptune is showing to be far more
    detailed months before encounter than Uranus was at VOYAGER 2's
    closest approach.
    
    	Larry
      

    	FYI, in the July, 1989 issue of "Sky & Telescope" there are
    a couple of articles on Voyager 2 including one very good article
    describing the upcoming encounter with Neptune. Included in the
    article are the investigations to be performed, an event timetable,
    and some expected results. It is highly recommended reading.
    
    				Drew
    

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager update
Date: 22 Jun 89 18:46:54 GMT
Organization: The Internet
 
    Extracted without permission from  the _Voyager Bulletin_, Mission
Status Report No. 87, June 15: 
 
    Three months before Voyager 2's closest approach to Neptune, the
spacecraft is returning images of the planet that show an unexpectedly
dynamic atmosphere on the eighth planet from the Sun.  A recently
released set of five images, taken on May 24 when the spacecraft was
134 million kilometers (83 million miles) from the planet, shows the
large dark spot, smaller white spot, atmospheric banding, and
brightening at the south pole seen in earlier images. The images were
taken through five different filters on Voyager 2's narrow-angle
camera.  The planet's appearance differs markedly as it is
photographed in different colors, probably because of differences in
colors of specific cloud features and the effects of hazes.  Bright
features are more visible in green and orange light, while darker
features show more contrast in violet and blue light.  The degree of
dynamic activity was unexpected in Neptune's atmosphere because
Neptune receives only one-tenth of one percent as much solar energy as
does Earth. 
 
    NASA SELECT TV TO FEATURE VOYAGER 2 NEPTUNE IMAGES
 
    Beginning Tuesday, June 13, at noon EDT, a selection from the
previous week's images of Neptune from the Voyager 2 spacecraft will
be broadcast on the NASA Select TV system, which uses Satcom F2R,
transponder 13, every Tuesday through August 8.  NASA Select TV is
available only in the contiguous United States since the Satcom
satellite is in geosynchronous orbit over North America. 
 
    The broadcast of the images is expected to last about 1 hour and
will show a replay of the first-order reconstruction of Voyager 2's
imaging system views of Neptune.  At the time of the first image in
the first broadcast, Voyager 2 was nearly 2-2/3 billion miles from
Earth and approximately 71 million miles from Neptune. 
 
    On June 5, the Voyager 2 spacecraft went into the Observatory
phase mode. In this mode the spacecraft begins a series of imaging
observations of Neptune from afar.  Five images are taken every 3
hours, 34.4 minutes (one-fifth of Neptune's estimated rotation
period).  Voyager planetary scientists will use these images to help
study the Neptune atmosphere, already seen to be more turbulent than
that of Uranus and possessing what appear to be variable "white"
spots, covering portions of whole hemispheres.  The spots come and go
with relative rapidity.  Dr. Brad Smith, University of Arizona, said,
"Neptune is now more interesting than Uranus was even at close
encounter." Dr. Smith is the Voyager Imaging Team leader. 
 
    The timetable for NASA Select replay of Voyager 2 images, along
with the distance remaining to Neptune and the distance from Earth at
the start of each broadcast, is given below: 
 
Broadcast 	Distance to Neptune	Distance from Earth
  Date             (million miles)	  (billion miles)

June 13			70.70			2.65
June 20			64.40			2.65
June 27			59.00			2.66
July 4 *		53.73			2.66
July 11			48.30			2.66
July 18			42.88			2.67
July 25			37.45			2.68
August 1		32.03			2.69
August 8		26.60			2.70
 
* - This date may move later in the week due to holiday observance.
 
    The images to be replayed on NASA Select will include both the
actual image of Neptune as seen by Voyager and engineering and science
information about the conditions of the imaging system and lighting. 
This data will appear alongside each image of retransmissions but will
be removed in later, more processed views. 
 
    Because the JPL facilities associated with the Voyager project are
not completely geared up for the close encounter activity, these views
will be released in video format via satellite only.  There will be no
capability to release individual still photos for the complete video
series.  Current expectations, though, include the capability to
release, on a periodic basis, a set of hard copy views which have
received the benefit of further computer enhancement.  JPL's complete
computer processing capabilities will be up and running, though, for
the encounter period from August 21 through 29. The Post-encounter
phase runs from August 29 through October 2, at which time Voyager 2
will return to interplanetary cruise mode. 
  
    Peter Scott ([email protected])

    	In regards to earlier Notes in this Topic discussing the fact
    that the VOYAGER spacecraft are moving faster than the PIONEER probes
    and will overtake them in their outward journeys over the next few
    decades, I have the following figures on the events, supplied from
    the book by Mark Littmann, PLANETS BEYOND: DISCOVERING THE OUTER SOLAR 
    SYSTEM, which I highly recommend.
    
    	PIONEER 10 is currently travelling 2.384 astronomical units (AU)
    per year (one AU equals 93 million miles, the average distance from
    Sol to Earth).  PIONEER 11 is making 2.214 AUs per year.  VOYAGER 1
    is covering 3.501 AUs per year, and VOYAGER 2 is moving at 3.386
    AUs per year.
    
    	VOYAGER 1 will overtake PIONEER 10 in distance in 1998; VOYAGER 2 
    will accomplish the same task in the year 2016.
    
    	Larry
    

    I hear they're going to raise the speed limit to 5 AUPY in some of the
    outlying regions of the solar system...
    
John

    They gonna make the Duke governor of Pluto?
    
    Actually, Uranus might be a better choice . . .

RE:< Note 532.23 by EPIK::BUEHLER "So who's the U-boat commander?" >

>    I hear they're going to raise the speed limit to 5 AUPY in some of the
>    outlying regions of the solar system...
    
HA!  I can see it now, the entire country on alert, jets in the air, ICBMs 
being readied as this flying saucer lands on the lawn of the White House.  
The world waits...

Suddenly a hatch opens and out steps a 2 headed purple people eater.  He
walks up to the nearest vehicle and indicates he wants to see the head of
NASA.  When the surprised director is brought forth the spaceman puts his
foot up on the bumper and says... 

^$%&$#^#*^YHLUG  &%*&^RYFG *&^(*%TCVHERGEW& 

which roughly translated means "OK buddy, where's the fire??!!"

He then writes a ticket for speeding and hands it to the chagrined director 
telling him to watch it or next time he'll wind up pumping methane on Neptune.

Then the space cop gets back into his saucer and flys back to his speed trap 
behind that big mountain on Pluto.

>which roughly translated means "OK buddy, where's the fire??!!"
    
    I love it.  I couldn't stop laughing.  Oh, the imagery that comes to
    mind...
    
John

Newsgroups: sci.space
Subject: Voyager 2 Status for 06/27/89 (Forwarded)
Date: 28 Jun 89 00:47:18 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                  Voyager 2 Status Bulletin   
                        June 27, 1989   
           
     Voyager 2 this week received and began executing the second load
of commands of the observatory phase of the Neptune encounter.  The
five-week-long command load continues imaging and periodic ultraviolet
scans of Neptune. In late July, the spacecraft cameras will begin
photographic searches for Neptune's uneven ring system and for new
Neptunian moons that would be undetectable from Earth. 
        
     Efforts on Wednesday, June 28, will focus on a rehearsal of radio
science measurements associated with the near-encounter period.  The
operations readiness test will involve antennas and other ground
equipment at the Deep Space Network complexes, the Very Large Array in
Socorro, New Mexico, Japan's Usuda Radio Telescope and Australia's
Parkes Radio Observatory.  Altogether, 38 antennas on four continents
will send or receive Voyager 2 telemetry or radio science data during
the Neptune encounter. 
   
     Because the best radio "view" of Voyager and Neptune is from
Earth's southern hemisphere, the most critical Deep Space Network
tracking will occur at the Australian site. Two of the three largest
antennas (one 34-meter and one 70-meter dish) will be assisted in
receiving Voyager's signal by the 64-meter Parkes Radio Observatory
about 200 miles away.  During the most important encounter period, the
huge, super-sensitive antennas will simultaneously gather Voyager's
faint transmissions, the strength of which amounts to only one
10-quadrillionths (1/10,000,000,000,000th) of a watt by the time the
signal strikes the 70-meter antenna surface.  An electronic digital
wristwatch operates at a power level 20 billion times greater. 
      
    DISTANCE TO EARTH:   2,663,767,000 miles   
    DISTANCE TO NEPTUNE:     52,687,000 miles   
    HELIOCENTRIC VELOCITY:   42,209 mph               

Newsgroups: sci.space
Subject: Voyager Status for 07/05/89 (Forwarded)
Date: 6 Jul 89 00:42:13 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
     Voyager Status Report - July 5, 1989 
  
     Voyager 2's television cameras this week remained the only
experiment on the spacecraft to detect Neptune, a fact that does 
not surprise Voyager scientists who anticipate that many of the
experiments will not "see" the Neptunian system until a month or 
even days before the spacecraft's closest approach. 
 
     The planetary radio astronomy (PRA) experiment, which detects
radio-wave emissions from planets, has not yet "heard" Neptune.  But
interestingly, the instrument is still hearing radio emissions from
Jupiter which, next to the Sun, is the noisiest radio source in the
solar system. 
 
     This Friday, the heating unit for the 20-inch mirror in the
infrared interferometer and spectrometer (IRIS) will be turned off to
allow the heat-mapping instrument to cool down to its approximately 0
degree Celsius (32 degree Fahrenheit) operating temperature.  When the
IRIS is not making observations, the heater is kept on to preserve the
instrument's sensitivity.  A 1 1/2-month cool-down period will ensure
the IRIS is ready for its most critical observations of heat emissions
from Neptune and Triton beginning about 10 days prior to Voyager 2's
closest approach to the planet. 
  
    DISTANCE FROM EARTH:  2,670,438,000 miles 
    DISTANCE FROM NEPTUNE:  45,495,000 miles 
    HELIOCENTRIC VELOCITY:  42,202 mph

Newsgroups: sci.space
Subject: NASA's Voyager 2 finds new moon around Neptune (Forwarded)
Date: 7 Jul 89 16:25:19 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Paula Cleggett-Haleim 
NASA Headquarters, Washington, D.C.                  July 7, 1989
 
Mary Beth Murrill 
NASA/Jet Propulsion Laboratory, Pasadena, Calif.
  
RELEASE:  89-110
 
    NASA's VOYAGER 2 FINDS NEW MOON AROUND NEPTUNE
 
     A new moon has been discovered orbiting Neptune, scientists on
the Voyager Project at NASA's Jet Propulsion Laboratory (JPL),
Pasadena, Calif., announced today. 
 
     The moon's discovery was confirmed Wednesday, July 5, when it was
located in images returned from the Voyager 2 spacecraft enroute to
Neptune.  Temporarily designated 1989 N1, the new moon was initially
seen in Voyager 2 images transmitted to Earth in mid-June.  Later images 
showing the small body in its predicted orbit confirmed its existence. 
 
     Dr. Stephen P. Synnott, a Voyager imaging team scientist at JPL,
found the small, bright smudge in Voyager pictures that led to the
moon's discovery.  According to Synnott, the new Neptunian satellite
could range in diameter from about 125 miles to 400 miles and is in a
very nearly circular, equatorial orbit about 57,600 miles from the
planet's cloud tops or 73,000 miles from the planet's center. 
 
     At this point, the moon is too indistinct to appear in photographic 
prints made from the Voyager images.  Pictures taken in coming weeks will 
show the moon more clearly. 
 
     The moon cannot be seen from Earth because the moon is so close
to Neptune that the brightness of the planet itself masks the tiny
point of light.  Voyager 2 will continue to study the moon and conduct
searches for others as it approaches the planet. 
 
     Neptune has two other known moons:  Triton discovered in 1846 and
Nereid discovered in 1949.  Triton is between 1,500 to 2,500 miles in
diameter.  Nereid probably is between 200 miles to 700 miles in diameter. 
 
     Voyager 2 is now 43 million miles away from Neptune and will make
a close pass of the planet on Aug. 24, 1989.  The spacecraft was
launched in 1977 and flew past Jupiter in 1979, Saturn in 1981 and
Uranus in 1986.  The Neptune encounter will be the final planetary
flyby of the Voyager mission, which also included Jupiter and Saturn
flybys conducted by twin spacecraft Voyager 1. 
 
     The Voyager mission is managed by JPL for NASA's Office of Space
Science and Applications, Washington, D.C. 

Newsgroups: sci.space
Subject: Voyager Status for 07/07/89 (Forwarded)
Date: 7 Jul 89 16:27:42 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                        July 7, 1989
  
      Voyager team scientists have found a new moon in orbit around Neptune.  
     
     The discovery was confirmed Wednesday when the moon was located
in images from Voyager 2.  Temporarily designated 1989 N1, the new
satellite was initially seen in images transmitted to Earth in
mid-June.  Its existence could not be confirmed, however, until later
images showed the small body in its predicted orbit. 
     
     Dr. Stephen P. Synnott, a Voyager imaging team scientist at JPL,
found the small, bright smudge in Voyager images that led to the
moon's discovery.  According to Synnott, the new Neptunian satellite
could range in diameter from 200 to 600 kilometers (about 125 to 400
miles) and orbits in a very nearly circular and equatorial orbit about
92,700 kilometers (about 57,600 miles) from the planet's cloud tops
(or about 117,500 kilometers (73,000 miles) from the planet's center).
     
     At this point, the moon is too indistinct to appear in
photographic prints made from the Voyager images, but pictures taken
in coming weeks will show the moon more clearly. 
 
     1989 N1 cannot be seen from Earth because the moon is so close to
Neptune that the brightness of the planet itself masks the tiny point
of light.  Voyager 2 will continue to study the moon and conduct
searches for others as it approaches the planet. 
    
     Moons known to orbit Neptune now total three.  The other two,
Triton and Nereid, were discovered in 1846 and 1949, respectively. 
 
     Ultimately, 1989 N1 will be given a name drawn from mythology
associated with Neptune, in accordance with nomenclature protocol set
by the International Astronomical Union. 
  
    DISTANCE FROM EARTH:    2,672,377,000 miles
    DISTANCE FROM NEPTUNE:  43,696,000 miles
    HELIOCENTRIC VELOCITY:  42,200 mph

    Has the Voyager II video that's being sold commercially been discussed
    in this conference?  (Assembled [entirely?] from Voyager-returned
    images, according to a Boston Globe review.)   - John C.

Newsgroups: sci.space
Subject: Voyager Status for 07/11/89 (Forwarded)
Date: 15 Jul 89 06:36:19 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                        July 11, 1989
  
     Voyager 2's discovery last week of a new Neptunian moon has
scientists rethinking theories about the origin of Triton. 
 
     The new moon, 1989 N1, orbits Neptune in a tidy, nearly circular
orbit around the planet's equator.  The orderliness of its orbit makes
it an anomaly when compared with the two other known Neptunian moons,
Triton and Nereid, which occupy unruly orbits around the planet. 
Triton's orbit is retrograde, or backward, and inclined at about 20
degrees to the equator.  Nereid has a prograde, or forward, orbit that
is inclined 30 degrees to Neptune's equator. 
 
     Before last week's discovery, scientists thought that because of
Triton's peculiar retrograde and tilted orbit, it must have been a
body wandering the solar system alone when it was captured by Neptune.
But now, with the discovery of 1989 N1, "The difficulty we have is
that we've found a moon in a place we didn't think one should have
existed," said assistant project scientist Dr. Ellis Miner. 
 
     If Triton were a relative newcomer to the Neptune system, Miner
said, it would have passed near enough to the low orbit of any
preexisting moon such as 1989 N1 either to collide with it or sweep it
up through gravitational attraction.  Therefore, the existence of 1989
N1 in the orbit it occupies suggests that Triton may not be a captured
object, but instead be a native to Neptune.  Theoreticians are now
battling with this new discovery to see if the Triton-as-captured-object 
theory can be salvaged or if alternative explanations for its retrograde 
orbit can be found. 
  
    DISTANCE FROM EARTH:    2,675,488,000 miles
    DISTANCE FROM NEPTUNE:  40,999,000 miles
    HELIOCENTRIC VELOCITY:  42,198 mph

Newsgroups: sci.space
Subject: Voyager Status for 07/18/89 (Forwarded)
Date: 19 Jul 89 17:46:55 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report 
                        July 18, 1989 
       
     Neptune's new moon, 1989 N1, is becoming a new guidepost for the
Voyager navigation team and is a candidate to help better determine
the location of Neptune itself. 
 
     Neptune was discovered in 1846, and the planet takes 165 years to
orbit the Sun; thus, Neptune won't return to the position where
astronomers first saw it until 2011.  This leaves great uncertainty in
the precise knowledge of Neptune's orbit that Voyager navigators need
to get the spacecraft to the targeted area of the planet at the right
time.  But the new Neptunian moon, 1989 N1, will provide the
navigation team with a better idea of Neptune's exact location. 
 
     The discovery of the moon fulfilled expectations of Voyager
navigators who were hoping to find at least one new object in the
Neptune system whose orbit could potentially be used to gauge the
relative positions of Triton, Neptune and various background stars,
said Don Gray, Voyager Navigation Team Chief. 
 
     Many of the images coming back from the spacecraft are optical
navigation frames.  Ideally, the frames show a moon against a field of
stars.  Using stars as dim as 10th magnitude as reference points, the
Voyager navigators progressively update and refine the location of
Neptune and its moons.  This new information is then integrated into
commands that adjust Voyager's flight path and retarget the
spacecraft's observations, if necessary. 
 
     The next trajectory correction maneuver is being designed and
will be uplinked to the spacecraft late next week.  The maneuver is
one of the final three that will be conducted between now and closest
approach to bring the spacecraft within about 100 miles (150 kilometers) 
of the point at which its aimed - about 3,000 miles (4,850 kilometers) 
from Neptune's cloud tops. 
  
    DISTANCE TO EARTH:     2,686,949,000 miles 
    DISTANCE TO NEPTUNE:   33,805,000 miles 
    HELIOCENTRIC VELOCITY: 42,192 mph 

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: New satellite of Neptune
Date: 20 Jul 89 18:17:57 GMT
Organization: The Internet
 
    Excerpted without permission from NASA _Voyager Bulletin_, Mission
Status Report No. 88, July 12: 
 
    ADD A NEW NEPTUNIAN MOON
 
    A new moon has been discovered orbiting Neptune.  Temporarily
designated 1989 N1, the new moon was initially seen in images
transmitted to Earth by Voyager 2 in mid-June.  Its existence was
confirmed upon examination of other images after the moon's orbital
motion had been calculated and its position could be predicted. 
 
    The new Neptunian satellite could range in diameter from 200 to
600 km (about 125 to 400 miles) and oribts in a very nearly circular
and equatorial orbit about 92,700 km (about 57,600 mi) from the
planet's cloud tops (or about 117,500 km) (73,000 mi) from the
planet's center). 
 
    A permanent name will be given to the moon at a later date by the
International Astronomical Union (IAU). 
 
    According to Dr. Stephen P. Synnott, a Voyager imaging team
scientist at JPL, the satellite appeared as a small, bright smudge in
Voyager pictures due to the long (46-second) exposure.  At this point,
the moon is too indistinct to appear in photographic prints made from
the Voyager images. Pictures taken in coming weeks will show the moon
more clearly. 
 
    1989 N1 cannot be seen from Earth because the moon is so close to
Neptune that the brightness of the planet itself masks the tiny point
of light. Voyager 2 will continue to study the moon and will conduct
searches for others on approach to the planet.  [...] 
 
    The moon orbits well outside the orbits of the postulated ring
arcs.  Its existence lessens concerns about radiation hazards to the
spacecraft near the planet, since the moon probably sweeps charged
particles out of the area as it orbits Neptune.  
 
    Peter Scott ([email protected], speaking only for myself)

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager rebroadcast frames deciphered
Date: 20 Jul 89 18:27:02 GMT
Organization: The Internet
 
    Extracted without permission from NASA _Voyager Bulletin_, Mission
Status Report No. 88, July 12: 
 
    WHAT DO THE HIEROGLYPHICS MEAN?
 
    Images and some of the other data received at JPL from the two
Voyager spacecraft are sent to display devices at JPL from the
computers in JPL's Multimission Image Processing System.  A subset of
these data, primarily images, is being broadcast on the NASA Select TV
channel by the GE Satcom F2R satellite.  Currently there is a one-hour
broadcast every Tuesday through August 8.  Broadcasts will probably be
more frequent as Voyager 2 nears its closest approach to Neptune on
August 25. 
 
    The frames that appear on the monitors are black and white only
and include basic identification information for the image being
displayed, as well as information about the processing that has been
applied to that image.  Data from the Planetary Radio Astronomy and
Plasma Wave investigations can also be displayed on video devices. 
The following is a brief summary of the information shown for imaging,
PRA, and PWS frames. 
 
    IMAGING FRAMES
 
    Each Voyager spacecraft carries two imaging cameras: a 200-mm,
f/3.5 wide-angle camera using a refracting telescope and a 1500-mm
f/8.5 narrow-angle (telephoto) camera using a reflecting telescope. 
Each camera uses a one-inch selenium-sulfur vidicon to convert an
optical signal into electrical signals. Each frame consists of 640,000
pixels, each of which is expressed as a level of gray on a scale from
0 (black) to 255 (white).  Color scenes are reconstructed on Earth by
electronically combining images taken through different filters. The
sensitivity of the filters ranges from 3460 (ultraviolet) to 6184
angstroms (red-orange). 
          
    [The rest of this extract contains mostly information of interest
to those people receiving the images.] 
 
    The elements of the displayed imaging frames are described below:
 
    [1-5 run left-to-right across the top line of the frame]
 
    1.  MIPL  Multimission Image Processing System (a JPL facility).
 
    2.  Spacecraft identifier
 
    3.  System Source:  RLTM  Real Time.  The data is displayed from
telemetry as soon as the data arrives at JPL; this data may be only 4
hours old (as long as it took for the data to travel from the
spacecraft to Earth); it may have been taken earlier, recorded on the
spacecraft's digital tape recorder, and played back to Earth at an
optimum time; or it may have been stored at the Data Capture and
Staging computer and read from there later. (See item 13, to learn
when the data was received at Earth.) 

    INTR  Interactive.  Image is displayed from a work station where a
scientist or analyst is interactively enhancing the data. RPLA 
Replay, for NASA Select TV, of data received earlier. 
 
    4.  Target Body (Neptune, Triton, Nereid, rings, etc).
 
    5.  FDS Count.  Image identifiction in units of spacecraft clock
time (the spacecraft's clock is in the spacecraft's Flight Data
Subsystem computers). 
 
    6.  Frame identification in units of picture number, planet, spacecraft,
and days from encounter  [displayed under #5].
 
    7.  Frame.  The data are displayed at half resolution.  As
displayed, the image area is 400 lines by 400 rows [sic] of picture
elements.  A full Voyager image frame is 800 lines of 800 elements,
but since the display devices can display only 640x480 pixels, every
other pixel of every other line is displayed. 
 
    8.  Reference Gray Scale [along left edge]
 
    9.  Histogram (frequency distribution) of number of bits at each
of the gray levels in the incoming image [top right]. 
 
    10. Histogram of number of bits at each of the gray levels in the
image as displayed at left.  [Center right].  (Note: the histograms
are an aid in evaluating the quality of the displayed image; e.g., how
bright was the image, how good was the exposure, etc). 
 
    11.  [Text under #10]  Describes processing that has been done to
transform the input image to the output image, e.g., magnification
factor, dark current subtraction, contrast enhancement. 
 
    12.  [Text, bottom left to center]  Identification information:
	INSTR  Instrument:  ISSWA  Imaging camera, Wide angle
			    ISSNA  Imaging camera, Narrow angle
	FILTER  Clear, green, orange, blue, ultraviolet, methane (6910 or
		5410 angstroms), or sodium.
	EXP  Exposure time (seconds)
	IMODE  Shutter mode:
		NAONLY  Narrow angle only
		WAONLY  Wide angle only
		BOTALT  Wide and narrow angle shuttered alternately
		BOTSIM  Both wide and narrow shuttered simultaneously
		BODARK  Neither wide nor narrow shuttered (used to calibrate
			background noise (or "dark current"))
		NOSHUT  Neithr wide nor narrow read out
	TMODE  Spacecraft telemetry mode at which data is read out (e.g.
	       compressed, edited, slow scan, etc).
	RANGE  Distance from spacecraft to center of target body, in km.
	INA  Lighting angle (incidence angle of sunlight striking target)
	EMA  Viewing angle (emission angle of sunlight reflected from target)
	PHA  Phase angle (angle between incoming sunlight and emitted or
	     reflected light from target)
	SCALE  Distance across frame (at the target body)
 
    13. [Bottom right]  Time signal was received at Earth (day of
year:hour:minute) in Universal Time Coordinated (UTC). 
 
    14. [Right of #13]  Calendar day (JPL local time), MIPS computer
ID, display device ID.  
 
    PLANETARY RADIO ASTRONOMY (PRA)
 
    The planetary radio astronomy experiment uses two 10-meter whip
antennas to listen for radio emissions from the Sun, planets, and
lightning in planetary atmospheres over a range from 1.2kHz to
40.5MHz.  The PRA high-rate receiver gives high time resolution at two
fixed frequencies that will be selected by the PRA science team when
the spacecraft is a few weeks away from the planet. At Uranus the
frequencies were 35.9424MHz and 1.230MHz. 
 
    Data from the PRA is sometimes displayed on the video devices. 
The following discussion indicates information that differs from the
Imaging frames: 
 
    7.  Frame.  A high-rate PRA frame contains 48 seconds of data
formatted as 800 lines, each containing 800 8-bit samples.  The total
time per line is 0.06 second.  Only 1/4 of the PRA data is displayed
in the video convrsion of the frame.  The first 24 seconds of the
displayed frame represents signals at the first fixed frequency, at
two antenna polarizations.  The last 24 seconds show only one
polarization at the second fixed frequency.  "Real" signals show as
horizontal white (or light) streaks running across the frame [an
example is pictured showing lightning-like electrical discharges at
Uranus]. 
 
    The pattern observed in each line represents the "loudness" as a
function of time, of an "audio" noise signal in a narrow band centered
on the receiver frequency.  Real data increases the "loudness" of the
signal, just like extra static in a home radio.  The amount and type
of noise gives information about what causes it. 
 
    9.  Histogram of signal intensity as received (input).
 
    10. Histogram of signal intensity values as displayed (output).
  
    11.  Only INSTRU and TMODE have any meaning for PRA and PWS frames.
 
 
    PLASMA WAVES (PWS)
 
    Plasma waves are low-frequency oscillations in the plasmas in
interplanetary space and in planetary magnetospheres.  The plasma wave
instrument detects and measures plasma wave interactions in planetary
magnetospheres and detects interactions between a planetary
magnetosphere and the solar wind.  It can detect particles in the ring
plane and measure their impact rate on the spacecraft.  The PWS shares
the two whip antennas with the PRA investigation to provide the
equivalent of a single 7-meter antenna.  PWS covers the frequency
range from 10Hz to 56.2kHz. 
 
    The PWS high-rate receiver is a very sensitive audio amplifier. 
In the display of a Fourier transform of the data, the horizontal axis
is time (one 48-second frame) and the vertical axis is frequency. 
Plasma wave scientists interpret the signal patterns in terms of
various mechanisms the interactions of charged particles and
elctromagnetic waves.  Steady frequencies generally are associated
with interference signals from other subsystems on the spacecraft; for
example, the 2.4kHz hum of the spacecraft's power supply [shows up as
a horizontal line near the bottom of the sample frame]. 
  
    Peter Scott ([email protected])          Standard disclaimers.

Newsgroups: sci.space
Subject: Voyager Status for 07/25/89 (Forwarded)
Date: 25 Jul 89 23:34:59 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
  
                    Voyager Status Report
                        July 25, 1989
  
     Images of Neptune sent back by Voyager 2 in recent days show
evidence of surprising variability in the large-scale weather patterns
of the planet. 
 
     Two images taken 53 hours apart show the previously observed
small bright cloud breaking away from the edge of the large dark oval
that dominates Neptune's face. 
 
     A time-lapse movie of sequential Voyager images shows several
small cloud features moving across the disc of the planet as it
rotates.  (One Neptune rotation is about 18 hours.)  The smallest
detail visible in the images now is about 1,700 kilometers (1,000
miles) across.  The time-lapse images show Neptune's atmospheric
circulation and are being used by Voyager scientists to clock wind
speeds on Neptune. 
  
    DISTANCE TO EARTH:      2,694,587,000 miles
    DISTANCE TO NEPTUNE:    27,510,000 miles
    HELIOCENTRIC VELOCITY:  42,188 mph

    	I recently read a report entitled "Triton: Do We See to the
    Surface" by D.P. Cruikshank, R.H. Brown, L.P. Giver, and A.T. Tokunaga
    in the 21 July, 1989 issue of "Science". The purpose of the paper was
    to determine if Voyager 2 would be able to see to the surface of Triton
    or if its view would be obscured by haze or clouds.
    	Based on their own data as well as the work of others it appears
    that Voyager 2 WILL be able to see the surface of Triton. According to
    their analysis, Triton seems to have an atmosphere of nitrogen and
    methane [although the authors did not explicitly state it in their
    analysis, the data indicates an atmosphere composed of ABOUT 90%
    nitrogen and ABOUT 10% methane though noble gases and carbon monoxide
    could also be present]. Their best models [which are based on an
    uncertain knowledge of the optical properties of nitrogen and methane
    at low temperatures] indicate a surface pressure of 9 mbar [about 1% of
    Earth] and a temperature of about 55 K [-360 F].
    	It seems likely that methane ice occurs on the surface and/or in
    the atmosphere as a haze. The amount of nitrogen indicated in the
    spectra taken points towards gaseous nitrogen in the atmosphere as well
    as "condensed" nitrogen (i.e. liquid and/or ice) on the surface or
    forming a haze. In addition to a possible methane and nitrogen haze, it
    is likely that Triton has a photochemical haze similar to Titan (though
    much thinner). Overall, the optical density of Triton's atmosphere
    would be about 0.4 which is similar to Mars during periods of no dust
    storms. Under these conditions the surface of Triton should be visible
    as well as a haze layer on its limb (fingers crossed!).
    
    					Drew
    

From: [email protected] (The Master -- ttardis SuperUser)
Newsgroups: rec.arts.startrek,sci.space
Subject: NSS Dinners
Date: 28 Jul 89 01:19:07 GMT
Organization: Real Time Incorporated
 
    I got the following enclosure in my latest issue of the National Space 
Society magazine "Ad Astra" and thought some of you might be interested.  
Me, I can't afford it, but maybe some desperate netter can scrape together 
the dough:  (BTW: this is typed in exactly as it appears.) 
------------------------------------------------------------------------------
 
         IN CELEBRATION OF THE VOYAGER 2 ENCOUNTER WITH NEPTUNE
                             Gene Roddenberry
            The Board of Directors of National Space Society
                      The Original Cast of Star Trek
 
                        Cordially invite you to an
 
                            Informal Reception
 
               To see the encounter *live* from Voyager 2
                                  and
                  to meet the Original Star Trek Stars
 
                        Friday, August 25, 1989
 
                             5:00 - 7:00 pm
 
                                  at
 
                        Dabney Lounge and Gardens
                   California Institute of Technology
                         Pasedena, California
 
  $100 per person                                             Casual Dress
 
             CALL NSS (202) 543-1900 FOR YOUR INVITATION
  <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
 
         IN CELEBRATION OF THE VOYAGER 2 ENCOUNTER WITH NEPTUNE
                             Gene Roddenberry
            The Board of Directors of National Space Society
                      The Original Cast of Star Trek
 
                        Cordially invite you to a
 
                         Private Cocktail Buffet
                                 with the
                   Star Trek: The Next Generation Cast
 
                     on the closed set of Star Trek
 
                        Saturday, August 26, 1989
 
                             7:00 - 9:00 P.M.
 
                                   at
 
                           Paramount Pictures
                           5555 Melrose Avenue
                          Hollywood, California
 
  $1,000 per person                                          Informal Dress
                             Limited Seating
 
            CALL NSS (202) 543-1900 TODAY FOR YOUR INVITATION
------------------------------------------------------------------------------
 
-JT
______________________________________________________________________________
 
JT the LFM (Large Furry Marsupial)       UUCP: ...uunet!edsews!rel!ttardis!lfm

    
    	I heard through the grapevine that Voyager 2 recently completed a
    series of long exposure photographs which will be used to locate
    new moons of Neptune (in addition to Triton, Nereid, and the recently
    discovered 1989 N1). There should be an announcement of the search 
    results by the end of the week.
    
    				Drew

Newsgroups: sci.space
Subject: Voyager discovers 3 additional moons around Neptune (Forwarded)
Date: 3 Aug 89 19:59:15 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond                                    August 3, 1989
Headquarters, Washington, D.C.                        11 a.m. EDT
 
Mary Beth Murrill
Jet Propulsion Laboratory, Pasadena, Calif.
  
    RELEASE:  89-128
 
    VOYAGER DISCOVERS 3 ADDITIONAL MOONS AROUND NEPTUNE
  
     Images from NASA's Voyager 2 spacecraft have revealed three
additional new moons in orbit around Neptune, Voyager imaging team
scientists announced today. 
 
     The discovery brings to six the number of moons known to exist
around the blue planet, including one, 1989 N1, discovered by Voyager
2 last month.  The spacecraft, launched in 1977, has explored Jupiter,
Saturn and Uranus and will come within 3,000 miles of Neptune at 12
midnight EDT, Aug. 24, 1989. 
 
     Finding so many moons when the spacecraft was more than 22
million miles away from Neptune may mean there are many more to be
found in coming weeks, according to Voyager scientists. 
 
     The three newest Neptunian satellites, temporarily designated
1989 N2, 1989 N3 and 1989 N4, were tracked as candidate moons in
images returned by the spacecraft over a 5-day period.  When the
objects were found to follow predicted orbits, Voyager imaging
scientists yesterday were able to confirm them as moons of Neptune. 
Their temporary names designate the order in which they were
discovered. 
 
     Like 1989 N1, the three new moons occupy nearly circular and
equatorial orbits around the planet.  All move in prograde orbits (in
the same direction the planet rotates), making the large moon Triton,
which occupies a retrograde orbit, even more of an oddity in the
Neptune system. 
 
     The innermost of the new moons is 1989 N3, which orbits at a
distance of about 32,300 miles from the center of the planet or about
17,000 miles from Neptune's cloud tops.  It makes one complete orbit
of Neptune every 8 hours, 10 minutes. 
 
     Next is 1989 N4, orbiting about 38,000 miles from the planet's
center or about 23,300 miles from the cloud tops.  It orbits the
planet every 10 hours, 20 minutes. 
 
     The outermost is 1989 N2, orbiting at about 45,400 miles from
Neptune's center or about 30,000 miles from the cloud tops.  It
completes an orbit every 13 hours, 30 minutes. 
 
     The three new moons exist in the region where partial Neptunian
rings or "ring arcs" are thought to exist.  If ring arcs exist, the
new moons might play an important role in "shepherding" and
maintaining them, Voyager scientists said.  The search for moons and
visible ring arcs will continue as Voyager 2 flies toward Neptune. 
 
     Several sequences of spacecraft activity include plans to point
Voyager 2's cameras at any newly discovered ring arcs or moons. 
 
     The Voyager Mission is conducted by the Jet Propulsion
Laboratory, Pasadena, Calif., for NASA's Office of Space Science and
Applications. 

Newsgroups: sci.space
Subject: Voyager Status for 08/01/89 (Forwarded)
Date: 3 Aug 89 20:03:13 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                       August 1, 1989
  
     Voyager 2 began executing a maneuver today that, when completed,
will give the one-ton spacecraft a 2.1 mile per hour boost in velocity
and move the spacecraft slightly sideways toward its target area at
Neptune. 
 
     The change in velocity and direction will put the spacecraft
closer to its scheduled flyby of Neptune on Aug. 24 at 9 p.m. PDT when
Voyager streaks just 3,000 miles over the planet's northern polar
region.  Two more trajectory corrections are scheduled before
Voyager's closest approach. 
 
     Data from the spacecraft confirmed the beginning of a sequence
that will result in a 7.5-minute burn of Voyager's hydrazine
thrusters, scheduled to begin at 9:56 a.m. PDT. The actual burn had
started 4 hours and 2 minutes before, but Voyager's radio signal takes
that long to reach Earth.  The burn was timed to end at 10:03 a.m.
PDT, but mission controllers would not be able to confirm the success
of the maneuver until about 1:15 p.m. today after reviewing telemetry
from the spacecraft. 
 
     Neptune this week provided Voyager flight engineers with one more
clue as to its whereabouts.  Data from the spacecraft now show a
slight but detectable accelerating effect Neptune's gravity is
exerting on Voyager.  The minute acceleration "tells more about the
planet's mass and more about where the planet is," said Dr. Lanny
Miller, manager of the Voyager flight engineering office.  The point
at which the spacecraft began to feel Neptune's tug, he said, "is hard
to pin down. [The spacecraft] is always under the influence of the
planet's gravity, but you don't see it in the data until you're real
close.  We didn't really sense it until the last week." 
 
     This is the last week of Voyager's observatory phase. On
Saturday, Aug. 5, Voyager will embark on the "far encounter" phase of
its Neptune mission, marked by focused observations of specific facets
of the Neptunian system such as the large dark spot and smaller spots
in the atmosphere. Searches for moons and ring arcs will continue. 
  
    DISTANCE TO EARTH:      2,705,447,000 miles
    DISTANCE TO NEPTUNE:    21,215,000 miles
    HELIOCENTRIC VELOCITY:  42,187 mph

Newsgroups: sci.space
Subject: Voyager Status for 08/02/89 (Forwarded)
Date: 3 Aug 89 20:24:43 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
		Voyager Status Report
		   August 2, 1989
 
    Images from the Voyager 2 spacecraft have revealed three
additional new moons in orbit around Neptune, Voyager imaging team
scientists announced today. 
 
    The discovery brings to six the total of moons known to exist
around the blue planet, including one, 1989 N1, discovered by Voyager
2 last month.  Finding so many moons when the spacecraft was  more
than 22 million miles away from Neptune may mean there are many more
to be found in coming weeks, according to Voyager scientists. 
 
    The three newest Neptunian satellites, temporarily designated 1989
N2, 1989 N3 and 1989 N4, were tracked as candidate moons in images
returned by the spacecraft over a five)day period.  When the objects
were found to follow predicted orbits, Voyager imaging scientists
yesterday were able to confirm them as moons of Neptune.  Their
temporary names designate the order in which they were discovered. 
 
    Preliminary calculations indicate the objects may range from 100
to 200 kilometers (about 60 to 125 miles) in diameter. 
 
    Like 1989 N1, the three new moons occupy nearly circular and
equatorial orbits around the planet.  All move in prograde orbits (in
the same direction the planet rotates), making the large moon Triton,
which occupies a retrograde orbit, even more of an oddity in the
Neptune system. 
 
    The innermost of the new moons is 1989 N3, which orbits at a
distance of about 52,000 kilometers (32,300 miles) from the center of
the planet, or about 27,300 kilometers (about 17,000 miles) from
Neptune's cloud tops.  It makes one complete orbit of Neptune every 8
hours, 10 minutes. 
 
    Next out is 1989 N4, orbiting about 62,000 kilometers from the
planet's center, or about 37,300 kilometers (23,300 miles) from the
cloud tops.  It orbits the planet every 10 hours, 20 minutes. 
 
    The outermost is 1989 N2, at about 73,000 kilometers (45,400
miles) from Neptune's center, or about 48,300 kilometers (30,000
miles) from the cloud tops.  It makes an orbit every 13 hours, 30
minutes. 
 
    All three new moons exist in the region where partial Neptunian
rings, or "ring arcs," are thought to exist.  If ring arcs exist, the
new moons might play an important role in "shepherding" and
maintaining them, Voyager scientists said. 
 
    DISTANCE TO EARTH:      2,708,706,000 miles
    DISTANCE TO NEPTUNE:    19,416,000 miles
    HELIOCENTRIC VELOCITY:  42,187 mph

From: [email protected] (Steve Poole)
Newsgroups: sci.space
Subject: CNN reports on Voyager Neptune encounter
Date: 3 Aug 89 21:43:43 GMT
Organization: UT Center for Space Research, Austin TX
 
    CNN is running reports on the Voyager 2 Neptune encounter every
weeknight.  They say the reports run at 8 and 10 pm Eastern time.  But
they don't actually run the reports on the hour.  Sometimes not even
close.  The first report airs anywhere from 8 to 9, and the second
anywhere from 10 to 11. 
 
    The best thing about these reports is the images.  Last night they
showed a rotation movie.  You could see the storm that looks like
Jupiter's Red Spot, and a smaller storm. 
 
Steve Poole  
ARPA: [email protected]

From: [email protected] (Henry Spencer)
Newsgroups: sci.space
Subject: Re: Beyond Neptune
Date: 4 Aug 89 04:30:07 GMT
Organization: U of Toronto Zoology
 
    In article <[email protected]> [email protected] 
(Charles Daffinger) writes:

>Alternatively, if Voyager II heads out of the solar system, how much
>longer will we be able to maintain radio contact?  Will the probe be
>sending back information at that time, or will it be simply shut off 
>and left to drift?
 
    There was a paper in JBIS a few years ago, by some of the Voyager
people at JPL, addressing this.  There are several limits involved: 
attitude- control fuel, communications bandwidth, and electrical
power.  It turns out that the limit is electrical power.  The isotopes
in Voyager's power packs are decaying steadily, and the power output
is dropping accordingly. Sometime around 2010, as I recall, there is
no longer enough power to run the "housekeeping" systems plus the four
experiments that yield useful data in deep space, and it will be
necessary to start shutting things down. A few years later, there
isn't enough to run even the housekeeping systems alone, and that's
it.  Barring problems, control fuel will easily last that long, and
communications would not be a problem until rather later. Whether the
electronics will keep going that long is somewhat of an open question
-- both Voyagers have had non-fatal electronic failures already -- but
there is no definite reason to think they won't. 
 
    Whether the Voyagers will be shut down before then to save money on
control and monitoring efforts here on Earth is a separate question.

1961-1969: 8 years of Apollo.  |     Henry Spencer at U of Toronto Zoology
1969-1989: 20 years of nothing.| uunet!attcan!utzoo!henry [email protected]

    Voyager 2 at Neptune:  Key events (Sky&Telescope 7/89)
    
    8/6 "Far Encounter" sequence begins
    8/17 Infared measurements to determine temp of Neptune
    8/24
    	8:00 Predicted entry into Neptune's magnetosphere
    	15:42 "Near encounter" sequence begins
    	16:40 Best Nereid imaging(4,690,000km)
    	22:56 Begin 2-hr occulatation of ring zone by Sigma Sagittarii
    8/25
    	0:00  Closest to Nereid(4,670,000km)
    	0:48  Best ring-arc imaging
    	3:03  Inbound ring-plane crossing(78,380km)
    	4:00  closest to Neptune(29,180km)
    	4:06  Begin 49-minute occultation(Voyager is behind Neptune as
    seen from Earth)
    	5:30  Outbound Ring-plane crossing(115,930km)
    	6:06  Best color imaging of Triton(200,000km)
    	8:40  Best imaging of Triton(48,000km)
    	9:14  cloest to Triton(40,000km)
    	9:43  Begin 4-minute occultation(voyager is behind Triton as seen
    from Earth)
    8/28 Predicted exit from Neptune's magnetosphere
    8/29 "post-encounter"sequence begins
    9/1  Infrared  measurements to determine temp of Neptune
    10/2 Neptune encounter complete
    
    *Events are given in Universal time as they occur at Voyager 2.  Set
    your time accordingly.  Here in the states, EDT is 4 hours earlier, CDT
    5 hours, etc.  Due to Neptune's distance, signals take another 246
    minutes to reach Earth from the spacecraft.  Distances are to the
    center of the target object.
    
    Frank
    

Newsgroups: sci.space
Subject: Voyager 2/Neptune encounter background broadcasts (Forwarded)
Date: 4 Aug 89 21:03:24 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond
Headquarters, Washington, D.C.			   August 4, 1989
 
N89-58
 
    EDITORS NOTE:  VOYAGER 2/NEPTUNE ENCOUNTER BACKGROUND BROADCASTS
  
     On August 7 and August 14, NASA Select television will transmit
background information on the Voyager 2 Neptune encounter.  The
schedule is: 
  
 Noon - 12:45 pm EDT   Dr. Ed Stone, Voyager Project Scientist, 
                       will host a pre-encounter talk entitled, 
                       "Voyager 2's Encounter with Neptune"
 
12:50 -  1:20 pm EDT   "Voyager Encounter Highlights" tape
 
 1:30 -  2:30 pm EDT   Replay of Voyager images.
                      (Length of replay is unknown at this time.)
  
     Media representatives can downlink the broadcast from NASA Select
television, Satcom F2R, transponder 13, C-band, located at 72 degrees
W. longitude, 3960.0 MHz, vertical polarization, 6.8 MHz audio. 

From: [email protected] (Peter E. Yee)
Newsgroups: sci.space
Subject: Voyager Status for 08/08/89 (Forwarded)
Date: 10 Aug 89 18:32:51 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                       August 8, 1989
  
     Voyager 2 moved into its "far encounter" phase Sunday, stepping
up its studies of the planet's atmospheric features and continuing
searches for new moons and possible ring arcs. 
 
     More than two dozen previously planned photographs of the Neptune
system have been repointed toward interesting atmospheric features
such as the large dark spot and the bright, fast-moving clouds (dubbed
"scooters" by the science team) that move along the top edge of the
dark southern latitudinal band. 
 
     Studies of features in the atmosphere are yielding preliminary
calculations of Neptune's wind speeds.  Winds on Neptune at 55 degrees
south latitude seem to blow at a roaring 400 miles per hour -- similar
to the wind speed in the same region on Uranus. 
 
     Mission controllers this week sent commands to the spacecraft 
to boost the power in part of the narrow-angle camera.  The vidicon
television camera, which long ago began showing signs of age sooner
than its wide-angle companion camera, needed the added voltage to
bring it up to standard operation and ensure that it returns clear,
normal-contrast images throughout the encounter.  "Vidicons do have
limited lifetimes," said assistant project scientist Dr. Ellis Miner,
"but we restricted use of Voyager 2's narrow-angle camera at Saturn
and Uranus to save it for Neptune."  The heightened voltage is just
one of many ways the imaging team is able to maintain the camera's
sensitivity when needed, Miner added. "We still have ways to up its
sensitivity before it's no longer useful." 
  
    DISTANCE TO EARTH:      2,717,465,000 miles
    DISTANCE TO NEPTUNE:    14,918,000 miles
    HELIOCENTRIC VELOCITY:  42,190 mph

From: [email protected] (Peter E. Yee)
Newsgroups: sci.space
Subject: New system uses Artificial Intelligence to monitor spacecraft 
Date: 10 Aug 89 18:37:06 GMT
Organization: NASA Ames Research Center, Moffett Field, CA
 
Paula Cleggett-Haleim
Headquarters, Washington, D.C.                     August 7, 1989
 
Diane Ainsworth
Jet Propulsion Laboratory, Pasadena, Calif.
  
    RELEASE:  89-129
 
    NEW SYSTEM USES ARTIFICIAL INTELLIGENCE TO MONITOR SPACECRAFT
  
     Voyager 2's near encounter of Neptune in late August will provide
researchers at NASA's Jet Propulsion Laboratory (JPL), Pasadena,
Calif., with an opportunity to demonstrate a new expert system
designed to monitor the condition of interplanetary spacecraft and
ground operations. 
 
     The software demonstration, called the Spacecraft Health Automated 
Reasoning Prototype (SHARP), will be used by mission operators to better 
analyze radio signals from spacecraft as they are received through the 
Deep Space Network (DSN) ground stations and sent to the mission control 
center at JPL. 
 
     The computer program combines conventional computer science methods 
with artificial intelligence techniques to automatically detect and 
analyze potential spacecraft and ground data systems problems. 
 
     Designed by the JPL's Computer Science and Applications Section,
SHARP is written in the LISP programming language and uses an advanced
artificial intelligence programming tool, STAR*TOOL.  The program
supplies a variety of advanced techniques needed for building artificial 
intelligence systems to meet NASA's goals for future space exploration. 
 
     The SHARP team, headed by computer scientist David Atkinson,
earmarked Voyager 2's flyby of Neptune as a vigorous operational
setting in which to evaluate the performance of the SHARP system.  
The telecommunications subsystem of the spacecraft was chosen for 
the prototype demonstration because glitches frequently occur in 
the telecommunications link. 
 
     "The technology is being extended in the next year to monitor
other spacecraft subsystems, such as power, attitude and articulation
control and scientific instrumentation," Atkinson said.  "In addition,
SHARP will be used to monitor several spacecraft missions simultaneously, 
including the Magellan mission to Venus and Galileo mission to Jupiter." 
 
     The SHARP system provides a broad range of analysis functions to
aid in monitoring spacecraft and ground control systems.  Information
from a variety of data sources, for example, is centralized into a
single workstation.  SHARP automates processing and analysis of that
data to enable automatic fault detection and diagnosis using
artificial intelligence technology. 
 
     SHARP's expert system captures knowledge gained by Voyager
experts over the last 12 years and mimics their decisions when
problems arise.  That produces quicker response times to mission
anomalies.  The system furnishes operators with dynamic graphics
displays for viewing data in a variety of formats.  The status of the
spacecraft and ground stations can be determined at a glance through
the use of color-coded displays, which change to reflect status
updates or alarm conditions. 
 
     The automation efforts demonstrated in the SHARP system are
designed to enhance the productivity of mission operations in the
years ahead, reducing the workforce required to monitor spacecraft
during critical planetary encounter phases. 
 
     The Voyager Project is managed by JPL.  NASA's Offices of
Aeronautics and Space Technology and Space Science and  Applications
are sponsoring the SHARP demonstration. 

Newsgroups: sci.space
Subject: Voyager Status for 08/11/89 (Forwarded)
Date: 13 Aug 89 02:23:53 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                       August 11, 1989
 
     Voyager 2's imaging science team has found two of the long-sought-
after ring arcs, or partial rings, thought to exist around Neptune. 
 
     The arcs were found in photographs returned by the spacecraft
early this morning at NASA's Jet Propulsion Laboratory, Pasadena, Calif. 
 
     The two ring arcs are apparently associated with two of the new
Neptunian moons also found by Voyager 2 earlier this month.  Like the
moons, the arcs exist in the planet's equatorial plane.  One is about
50,000 kilometers (about 30,000 miles) in length; the second is about
10,000 kilometers (about 6,000 miles) long. 
 
     The first arc, the longer of the two, was seen just outside the
moon 1989 N4, which orbits about 62,000 kilometers (38,500 miles) from
the planet's center, or about 37,000 kilometers (23,300 miles) from
the planet's cloud tops. 
 
     The second arc appears to trail the moon 1989 N3 by approximately
90 degrees, or by about 80,000 kilometers or 50,000 miles.  That moon
orbits Neptune at a distance of about 52,000 kilometers (32,300 miles)
from the center of the planet, or about 27,300 kilometers (about
17,000 miles) from the planet's cloud tops. 
 
     Astronomers have long suspected the existence of such an
irregular ring system around Neptune.  Data from repeated ground-based
observations hinted at the existence of disorderly strands of partial
rings orbiting Neptune. Voyager's photographs of the ring arcs are the
first photographic evidence that such a ring system exists. 
 
     Voyager scientists said the ring arcs may be comprised of debris
associated with the nearby moons, or may be the remnants of moons that
have been torn apart or ground down through collisions.  Close-up
studies of the ring arcs by Voyager 2 in coming days should help
determine their composition. 
 
     More ring arcs are expected to be found as the spacecraft nears
the planet, Voyager scientists said. 
     
    DISTANCE TO EARTH:     2,722,948,000 miles
    DISTANCE TO NEPTUNE:   12,218,000 miles
    HELIOCENTRIC VELOCITY: 42,195 mph

Newsgroups: sci.space
Subject: Two partial rings of Neptune discovered by Voyager spacecraft 
Date: 13 Aug 89 02:27:33 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Paula Cleggett-Haleim
Headquarters, Washington, D.C.                    August 11, 1989
 
Mary Beth Murill
Jet Propulsion Laboratory, Pasadena, Calif.
  
RELEASE:  89-132
 
    TWO PARTIAL RINGS OF NEPTUNE DISCOVERED BY VOYAGER SPACECRAFT
  
     NASA's Voyager spacecraft imaging science team has found two of
the long-sought-after ring arcs, or partial rings, thought to exist
around Neptune.  The arcs were found in photographs returned by the
Voyager 2 spacecraft early this morning at NASA's Jet Propulsion
Laboratory, Pasadena, Calif. 
 
     The two ring arcs apparently are associated with two of the new
Neptunian moons also found by Voyager 2 earlier this month. The arcs
appear to partially wrap around approximately 45 degrees and 10
degrees, respectively, the planet's equatorial plane.  One is about
30,000 miles in length, and the second is about 6,000 miles long. 
 
     The first arc, the longer of the two, was seen just outside the
moon 1989 N4, which orbits about 38,500 miles from the planet's center
or about 23,300 miles from the planet's cloud tops. 
 
     The second arc appears to trail the moon 1989 N3 by approximately
90 degrees or about 50,000 miles.  That moon orbits Neptune at a
distance of about 32,300 miles from the center of the planet or about
about 17,000 miles from the planet's cloud tops. 
 
     Astronomers have long suspected the existence of such an
irregular ring system around Neptune.  Data from repeated ground-
based observations hinted at the existence of disorderly strands of
partial rings orbiting Neptune.  Voyager's photographs of the ring
arcs are the first photographic evidence that such a ring system exists. 
 
     Voyager scientists said the ring arcs may be comprised of debris
associated with the nearby moons or may be the remnants of moons that
have been ground down or torn apart through collisions.  Close-up
studies of the ring arcs by Voyager 2 in coming days should help
determine the rings' composition. 
 
     More ring arcs are expected to be found as the spacecraft nears
the planet, Voyager scientists said. 
 
     Discovery of the two arcs when the spacecraft was still about 13
million miles from Neptune gives the Voyager team time to schedule
detailed photography of the ring arcs when the spacecraft comes within
3,000 miles of the planet on Aug. 24 and 25. 
 
     The Voyager mission is conducted by the Jet Propulsion Laboratory
for NASA's Office of Space Science and Applications. 

Newsgroups: sci.space
Subject: NASA Select television schedule (Forwarded)
Date: 13 Aug 89 02:28:48 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Les Gaver
Headquarters, Washington, D.C.                   
 
Jim Kukowski
Headquarters, Washington, D.C.
 
Terry Brooks
Jet Propulsion Laboratory, Pasadena, Calif.
 
    N89-59
    NOTE TO EDITORS:  NASA SELECT TELEVISION SCHEDULE
 
     During August, NASA Select television will transmit a variety of
programs.  For the Voyager 2 flyby of the planet Neptune, NASA will
employ two satellites to transmit live images of the encounter from
August 21-29 only.  Below is a list of upcoming NASA television
events, including dates, times and satellite.  All times are Eastern.  
______  _______________ ____________________________ _________  
 
13      1:15 a.m.       GPS/Delta launch coverage    SATCOM F2R
                        begins from KSC, Fla.        
 
13      7:30 a.m.       STS-28 Shuttle landing       SATCOM F2R
                        coverage begins from         
                        Edwards AFB, Calif.
 
14      Noon-3:15 p.m.  Pre-recorded briefing on     SATCOM F2R
                        Voyager 2 findings with 
                        Dr. Stone, Project Scientist 
                        (46 min.), JPL, Calif.
 
                        Voyager highlights, with     
                        computer animation of 
                        encounters with all four 
                        planets, and images of
                        Jupiter, Saturn and Uranus, 
                        (30 min.), JPL, Calif.
 
                        New release of a 5-minute,
                        narrated video describing
                        Voyager 2's Neptune encounter,
                        which will occur Aug. 24/25, JPL
 
                        New, silent computer animation
                        of various aspects of the
                        encounter (730 second, unedited
                        scenes)
 
                        Collected Voyager long-range
                        images of Neptune (b/w, 
                        silent) from Aug. 9-12
 
                        Voyager 2: The Neptune       
                        Encounter (pre-encounter
                        clip, plus computer graphics,
                        JPL
 
                        Playback of Voyager/Neptune  
                        images taken Aug. 8-13, JPL
 
15      8-10 a.m.       Live Neptune images from     SATCOM F2R
                        Voyager 2, JPL, Calif.       
 
16      2-4 p.m.        Live Neptune images from     SATCOM F2R
                        Voyager 2, JPL, Calif.       Aurora 1 (test)
 
17      9-11 a.m.       Live Neptune images from     SATCOM F2R
                        Voyager 2, JPL, Calif.       
 
18      8-10 a.m.       Live Neptune images from     SATCOM F2R
                        Voyager 2, JPL, Calif.
 
18      11 am-1:30 pm   Galileo spacecraft/STS crew  SATCOM F2R
                        photo op., KSC, Fla.
 
20      Noon            Galileo program press        SATCOM F2R
                        conference from JPL, Calif.
  
           VOYAGER 2 NEPTUNE ENCOUNTER (2 SATELLITES)
                           AUG. 21-29
 
     Daily programming from NASA's Jet Propulsion Laboratory, (JPL),
Pasadena, Calif., will begin at noon and continue through
approximately 8:30 p.m.  Coverage will be expanded on August 24 when
Voyager is nearest to Neptune. 
 
     The NASA television transmissions will be hosted by Dr. Albert
Hibbs and other JPL scientists.  Status reports will be provided
hourly, vary in length from 10 to 30 minutes and will include
interviews and presentations by mission scientists. Neptune encounter
news briefings are scheduled daily at 1 p.m. and will include more
formal scientific presentations. 
 
     The second satellite transponder will be used during the flyby to
provide television access to Alaska and Hawaii and a vastly improved
television signal for the western United States.  
 
21-23   Noon-8:30 p.m.  Voyager/Neptune Encounter,   SATCOM F2R
                        from JPL, Calif.             Aurora 1
 
24      Noon-TBD*       Voyager/Neptune Encounter,   SATCOM F2R
                        from JPL, Calif.             Aurora 1
* Determined at encounter time, depending on data received.
 
25-28   Noon-8:30 p.m.  Voyager/Neptune Encounter,   SATCOM F2R
                        from JPL, Calif.             Aurora 1
 
29      Noon-3:30 p.m.  Voyager/Neptune Encounter,   SATCOM F2R
                        from JPL, Calif.             Aurora 1
 
     In addition, uninterrupted real-time Voyager downlink images of
the encounter, without commentary, will be transmitted from 8:30 p.m.
through 2:30 a.m., Aug. 21-23 and 25-28. 
 
     For Voyager 2/Neptune encounter technical assistance, contact Jim
Roberts on XXX/YYY-ZZZZ. 
 
     Mission status reports will be carried, August 19-31, on a
special 900 phone line and two conventional phone lines.  On August
21-29, two of the lines also will carry live audio from daily press
conferences and another phone line will carry live audio from the
press conferences and audio from NASA Select TV. 
 
     The phone numbers are:
 
     (900) 590-1234
     Status reports and press conference audio;
     45 cents for first minute, 35 cents per additional minute
 
     (818) 354-4227
     Status reports and press conference audio; 
     Normal long-distance charges
 
     (818) 354-0409
     Status reports only
     Normal long-distance charges, if any, apply
 
     (818) 354-7292
     Press conference and NASA Select television audio;
     Normal long-distance charges
 
     The NASA Headquarters audio news service will carry status
reports and up-to-date NASA Select TV schedules on 202/755-1788. 
 
     The satellite video sources are:
 
GE Satcom F2R              Aurora 1
Transponder 13             Transponder 21
72 degrees W. Long.        143 degrees W. Long.
3960 MHz, vert. polar.     4120 MHz, vert. polar.

From: [email protected]
Newsgroups: sci.space
Subject: NSS Hotline Update
Date: 13 Aug 89 22:27:00 GMT
 
    This is the National Space Society Space Hotline updated August 10.
  
    The Voyager 2 spacecraft has entered the far encounter stage. The
large dark spots circling the planet and the bright fast moving clouds
which have been dubbed`scooters' are a focus of interest by project
scientists. Spacecraft controllers have been sending instructions to
the spacecraft to boost electrical power to the narrow angle TV camera
to increase sensitivity. 
 
    The NATIONAL SPACE SOCIETY has announced plans to cover the
exciting near encounter phase of the Voyager 2 Neptune fly-by with a
special edition of the popular Dial-A-Shuttle service called
Dial-A-Planet. Dial-A-Planet will be available from 6am PDT on August
24 to 6am PDT on August 26. D-A-P can be reached by calling
1-900-909-NASA, information on optimum times to call will be recorded
on this tape as it becomes available. As a reminder, there are toll
charges for these calls. 
 
    This has been the NSS Space Hotline. This tape will be updated as
information warrants, or no later than August 14. Thanks for calling. 

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager update
Date: 14 Aug 89 21:52:51 GMT
Organization: The Internet
 
    Extracted without permission from NASA's _Voyager Bulletin_,
Mission Status Report No. 89, August 7: 
 
    Moons, Moons, Moons

    [Stuff which has already been reported here several times.]
 
    The computer sequence that contains the instructions for Voyager
2's near-encounter observations has recently been altered to add one
image of 1989 N1 from a distance of 140,000 km (87,000 mi), about 45
minutes before [closest approach].  The image will be shuttered during
a radio science antenna calibration maneuver, which fortuitously turns
the spacecraft at just the right rate to remove most of the image
smear which would otherwise result because of the high relative
velocities between the spacecraft and the target.  The resulting image
should show surface features as small as 3 km (2 mi) on this small moon.  
[...] 
 
Moon or Ring Arc       Orbital Radius (from Center of Neptune)   Orbital Period
-----------------     ----------------------------------------- ---------------
Postulated Inner Arc         42,000 km     (26,100 mi) *          ~6 hrs
1989 N3                      52,000 km     (32,300 mi) *           8 hrs 10 min
Postulated Interior Arc      57,000 km     (35,420 mi) *          ~9 hrs
1989 N4                      62,000 km     (38,500 mi) *          10 hrs 20 min
Postulated Outer Arc         67,000 km     (41,600 mi) *         ~12 hrs
1989 N2                      73,000 km     (45,400 mi) *          13 hrs 30 min
1989 N1                     117,650 km     (73,100 mi)            26 hrs 56 min
Triton                      354,590 km    (220,340 mi)     5 days 21 hrs
Nereid                    5,510,660 km  (3,424,300 mi)   359 days
 
    [* I guess these readings go to demonstrate the advantage of American
units of measurement, since they clearly result in superior accuracy. :-) ]
 
    Subtract one Neptune radius (24,712 km at 1 bar pressure level) to
calculate distance from Neptune's cloudtops.  
 
    Course Correction

    Voyager 2's path towards Neptune was fine-tuned slightly on August
1, when a course correction moved the spacecraft slightly sideways and
changed its velocity by about 2.1 mph.  After re-orienting itself as
instructed by flight controllers, the spacecraft expelled pressurized
hydrazine (N2H4) for about 7.5 minutes to change its course. 
 
    At launch, each Voyager spacecraft carried about 105 kg (230 lbs)
of hydrazine propellant in a pressurized tank.  To date, Voyager 2 has
expended about 64 kg (140 lbs) of hydrazine.  [...] 
 
    [...]  Accurate delivery of the spacecraft to the Neptune aimpoint is 
especially important to the radio science experimenters, who must know the 
timing of the start of the spacecraft's disappearance behind Neptune as 
seen from Earth (Earth occultation) with an accuracy of 1 second.  
 
    Neptune's Weather

    Neptune's cloudtops show a surprising amount of variability,
considering that Neptune receives about 2-tenths of a percent as much
power per unit area as does Earth, and about 4 percent as much as
Jupiter.  These estimates take into account both energy received as
sunlight and energy upwelling from the planet's interior.  This energy
is a factor in creating weather systems on all planets. 
 
    While the large dark oval, first seen this spring, has remained
relatively constant in position, a bright cloud to the north and east
was seen to separate from the dark spot over a 53-hour interval from
July 9 to 12.  In addition, a smaller dark spot apparent in the dark
collar near the south pole rotates faster than the large dark spot.
This finding indicates that the winds on Neptune have different
velocities at different latitudes, as is the case for Jupiter, Saturn,
and Uranus. 
                                      
    Peter Scott ([email protected])

From: [email protected] (Henry Spencer)
Newsgroups: sci.space
Subject: Re: Voyager History
Date: 15 Aug 89 02:03:27 GMT
Organization: U of Toronto Zoology
 
    In article <[email protected]>
[email protected] (Will Martin) writes: 

>... This was so early that "Voyager" was not yet named.  The article
>just described a "Grand Tour" mission using two spacecraft without calling
>them anything.  [From August 1970 issue of NATIONAL GEOGRAPHIC.]
>
>What I was wondering about was the rationale for the fact that Voyager 1
>did NOT take advantage of the planetary alignment and also go to Uranus
>and Neptune like Voyager 2 did. This article doesn't really help ...
 
    The reason it doesn't help is that you are confusing two quite
different missions.  "Grand Tour" was CANCELLED.  Killed.  Dead as a
doornail. Voyager was *not* a renaming of "Grand Tour"; it was a
renaming of "Mariner Jupiter-Saturn".  The latter project was
basically an attempt to salvage something from the ruins of the
former.  As per the latter's original name, Jupiter and Saturn were
the primary mission objectives, with Uranus and Neptune seen as
just-barely-possible optional bonuses.  So the trajectories were aimed
primarily at Jupiter/Saturn data return, while preserving the option
of an extended mission for Voyager 2 *if* Voyager 1 performed well at
Jupiter and Saturn.  This meant no extended mission for V1, since the
fairly-rigid trajectory needed for the extended mission interfered
with getting the most out of Jupiter and Saturn.  One reason why the
V2 Neptune encounter is going to be fairly spectacular is the lack of
on-to-the-next- stop constraints on the trajectory. 

V7 /bin/mail source: 554 lines.|     Henry Spencer at U of Toronto Zoology
1989 X.400 specs: 2200+ pages. | uunet!attcan!utzoo!henry [email protected]

Newsgroups: sci.space
Subject: Voyager Status for 08/15/89 (Forwarded)
Date: 15 Aug 89 21:29:20 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                       August 15, 1989
  
     Voyager 2 navigators have already placed the spacecraft so
closely on target toward Neptune that today's scheduled trajectory
correction maneuver has been cancelled. 
 
     "It wasn't necessary to do it," said Dr. Lanny Miller, manager of
the Voyager flight engineering office.  "We're close enough to the aim
point that we can finish it off with TCM B20."  TCM B20 stands for
Trajectory Correction Maneuver Number 20, scheduled for August 21.  It
is the last fine-tuning effort to place the spacecraft at its closest-
approach target area.  Engineers are now designing the maneuver. 
 
     The infrared interferometer spectrometer and radiometer (IRIS)
began observing the Neptune system today.  The instrument will
determine the distribution of heat emitted by members of the Neptune
system, which will allow calculation of the temperature of those
objects.  The IRIS will also determine the temperature of the
atmospheres of Neptune and Triton at various altitudes. 
 
     Meanwhile, the imaging science team continues its search for more
moons and ring arcs, pointing Voyager's cameras at areas around
Neptune where such objects would most likely exist. 
  
    DISTANCE TO EARTH:      2,730,550,000 miles
    DISTANCE TO NEPTUNE:    8,618,000 miles
    HELIOCENTRIC VELOCITY:  42,209 mph

    	Another piece of info to add to .44; I saw a report that Voyager 2
    has finally been able to resolve the disk of Triton. At its present
    distance, the Voyager images have a resolution of about 150 km but
    Triton does show very distinct limb darkening and there do appear to be
    some "surface features" visible. The limb darkening could be caused
    by an atmosphere (like with Titan) or it would indicate an icy surface
    (like with the other moons of Saturn, for example). The observed
    "surface features" appear to be fixed and we could be seeing through
    Triton's atmosphere to the solid surface. These interpretations are
    tentative but the imaging scientist now seem cofident that Voyager 2
    will be able to see the solid surface of Triton during the flyby in 8
    days. Present estimates of Triton's diameter are still about 2,900 km
    give or take a couple hundred kilometers (i.e. slightly smaller than
    the Moon).
    
    	      			Drew
    

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager Update
Date: 16 Aug 89 17:45:53 GMT
Organization: The Internet
 
    Excerpted without permission from NASA's VOYAGER BULLETIN,
Mission Status Report No. 90, August 11: 
 
    Ring Arcs Confirmed!

    Voyager's imaging science team has found two of the long
sought-after ring arcs, or partial rings, thought to exist around
Neptune.  The arcs were found in photographs returned by Voyager 2
early in the morning on August 11. 
 
    The two ring arcs are apparently associated with two of the
Neptunian moons also found by Voyager 2 earlier this month.  The arcs
appear to wrap approximately 45 degrees and 10 degrees, respectively,
in the planet's equatorial plane.  One is about 50,000 km (about 30,000 
mi) in length; the second is about 10,000 km (about 6,000 mi) long. 
 
    The first arc, the longer of the two, was seen just outside the
moon 1989 N4, which orbits about 62,000 km (38,500 mi) from the
planet's center, or about 37,000 km (23,300 mi) from the planet's
cloud tops. 
 
    The second arc appears to trail the moon 1989 N3 by approximately
90 degrees, or by about 80,000 km (50,000 mi).  That moon orbits
Neptune at a distance of about 52,000 km (32,300 mi) from the center
of the planet, or about 27,300 km (about 17,000 mi) from the planet's
cloud tops. 
 
    Discovery of the two arcs when the spacecraft was still about 21
million km (13 million mi) from Neptune gives the Voyager team time to
schedule detailed imaging of the ring arcs when the spacecraft comes
withint 4,850 km (3,000 mi) of the planet the night of August 24/25. 
  
    Recorded Status

    Recorded mission status reports are now available by calling 
(818) 354-0409. 
  
    Far-Encounter Phase

    On August 6, Voyager 2 begins its eighteen-day "far encounter"
phase, which ushers in a higher level of activity that the
just-completed "observatory" phase.  Neptune's disk now captures about
one-quarter of the narrow-angle camera's field of view. 
 
    Higher activity also means more telemetry data, so NASA's Deep
Space Network (DSN) has added daily tracking coverage by the Very
Large Array (VLA) in New Mexico and the Parkes Radio Telescope in
Australia, in addition to 24-hour coverage by the DSN complexes. 
 
    The far-encounter phase started with an intensive series of scans
across the Neptunian system enabling the ultraviolet spectrometer to
search for auroral emissions from the planet.  These system scans
occur four or more times per day.  The imaging cameras are focussing
on the large-scale features in Neptune's atmosphere, the newly
discovered ring arcs, searches for new satellites, and on the other
known satellites, as well.  Bursts of high-rate data from the planetary 
radio astronomy (PRA) instrument and the plasma wave subsystem (PWS) 
are being recorded twice per day for later playback to Earth. 
 
    On August 11, the health of the infrared instrument (IRIS) was
assessed in preparation for the high-value observations later in far
encounter. Over the years, IRIS has experienced a degradation in its
sensitivity due to misalignment of its mirrors.  Periods of heating
(using tiny heaters on board the spacecraft) reduce crystallization of
mirror bonding material and restore some of the original sensitivity,
but stabilization of the instrument response requires several weeks of
cooling prior to data-taking. A strategy to maintain careful balance
and cooling periods has been applied. 
 
    As Voyager 2 homes in on Neptune, activities on board the
spacecraft require more of its computers' memory, so on August 13 the
current backup mission load (BML) will be permanently removed from
spacecraft to free up much-needed memory space.  Removing the BML is a
calculated risk, as the sequence is designed to autonomously operate
the spacecraft through a minimum set of encounter observations should
the spacecraft's only remaining radio receiver fail and prevent ground
controllers from sending further commands to the spacecraft.  Another
BML will be loaded in the post-encounter phase to protect future
long-term fields and particles observations in the outer solar system.
 
    Neptune's position is now known about three times more accurately
than just two weeks earlier; Triton three to six times better,
depending on the component.  Knowledge of the time of arrival is
one-third better.  Soon, the value of Triton's radius will no longer
be a mystery.  And by this time, the mass of Neptune is known three
times better than at the start of the far-encounter phase, because the
subtle tug of the planet's gravity can already be detected in
Voyager's radio data. 
 
    On August 15, Voyager 2 will again fine-tune its flight path,
following instructions arrived at after laborious computations by
Voyager's Navigation and Spacecraft Teams.  Immediately following this
trajectory correction, Voyager 2 will turn about its roll axis to
acquire a different lock star for its star tracker (the spacecraft
uses the Sun, Earth, and a star to maintain its orientation).  This 
change from Achernar to Canopus will place the onboard fields and 
particles instruments in a better orientation for measuring magnetospheric 
properties during the days before Neptune closest approach. 
 
    The highest-value science observations in this phase will be the
IRIS instrument's observations of the planet on August 16-18; the
matching outbound observation in the post-encounter phase is equally
important.  These observations will tell us the planet's temperature,
which may be combined with other Voyager data to provide the heat
balance -- the ratio of the amount of energy being given off by the
planet to the amount of energy it receives from the Sun.  This is a
highly important measurement to make for planets (especially the
gaseous ones) since it allows scientists to deduce things about the
body's interior, and unlock some of the secrets hidden by its clouds. 
The optimum times to make the heat balance measurements will be on
August 18 (inbound) and September 1 (outbound) when Neptune's disk
should just barely fill the IRIS instrument's field of view. 
 
    The final aiming point for the encounter will be fixed on August
20 with the final course correction of Voyager 2's 12-year odyssey to
the outer planets.  After this, no changes to the flight path are
planned -- ever -- for Voyager 2 [wonder why they left so much fuel to
spare, then - PJS]. Its fate will thus be transferred to the final
slingshot over Neptune's northern polar region and the meager forces
it may encounter in interplanetary and interstellar space. 
 
    This final maneuver is designed to adjust Voyager 2's position to
heighten the probability that Voyager 2 will pass through the narrow
area of space where Triton casts its shadow from the Sun and Earth. 
Critical observations of Triton's atmosphere depend on passing through
this region. 
 
    Peter Scott ([email protected])

Newsgroups: sci.space
Subject: Antenna in Japan to aid Voyager's radio science study of Neptune 
Date: 16 Aug 89 22:17:23 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond
Headquarters, Washington, D.C.                    August 16, 1989
 
Franklin O'Donnell
Jet Propulsion Laboratory, Pasadena, Calif.
  
RELEASE:  89-133
 
    ANTENNA IN JAPAN TO AID VOYAGER'S RADIO SCIENCE STUDY OF NEPTUNE
 
     A tracking station in Japan has been added to the network of
giant antennas trained on NASA's Voyager 2 during its flyby of Neptune
on August 25 to help the spacecraft mission's radio science experiment. 
 
     Scientists say they will be able to "see" twice as deeply into
the atmosphere of the giant gas planet, thanks to the participation of
the 210-foot antenna at Japan's Usuda Deep Space Center. 
 
     The collaboration was arranged through an agreement signed in
1988 between NASA and Japan's Institute of Space and Aeronautical
Studies (ISAS), which operates the Usuda center. Under the agreement,
physicist Dr. Nobuki Kawashima of ISAS will join the Voyager Radio
Science Team. 
 
     "Using Usuda will allow us to extract information on deeper parts
of Neptune's atmosphere," said Dr. Len Tyler of Stanford University,
principal investigator for the Voyager radio experiment.  "Also, the
quality of the data we will have for any given point will be twice as good." 
 
     During these observations, scientists will listen not to the
information carried by Voyager's radio signal but rather to the signal
itself -- especially its strength and frequency -- as the spacecraft
sails over Neptune's north pole and dips behind the planet. 
 
     Barely perceptible changes in the radio signal convey signatures
of the structure, composition and temperature of the seas of gases
that constitute Neptune's atmosphere, as well as of the planet's
gravity field. 
 
     As the spacecraft disappears behind a planet or moon from Earth's
point of view, its radio signal is refracted, or bent, during passage
through the planet's or moon's atmosphere. 
 
     Tiny changes in the signal's frequency and strength give
scientists a portrait of the atmosphere's structure, composition,
temperature and location of clouds, as well as information on
small-scale atmospheric dynamics. 
 
     Tyler likened the refraction effect to how a sunset appears on
Earth, as the Sun seems to linger at the horizon before it disappears.
"You would think that the Sun would appear to keep moving.  But
because its light is being refracted, you can continue to see it as
the Sun seems to stand still for a few moments," he explained. 
 
     In addition to studying atmospheres of planets and moons,
scientists have used the Voyagers' radio systems during the mission to
investigate the rings surrounding planets.  As the spacecraft flies
behind a ring system, changes in the radio signal provide information
not only on the rings' overall dimensions but also on the particles
that constitute the rings. 
 
     Also, the radio experiment is able to detect minute changes in
Voyager's velocity as it curves past each planet, offering a detailed
look at the planet's gravity field. 
 
     Some of the most significant findings from the radio experiment
during the 12-year Voyager Mission have included revelations on the
nitrogen atmosphere surrounding and the surface pressure at Saturn's
largest moon, Titan; measurements on wave-like structures within
Saturn's sprawling rings and the sizes of particles that constitute
them; detection of a methane cloud layer in the atmosphere of Uranus;
and the nature of Uranus's coal-black rings. 
 
     The experiment also has provided data on the densities of moons
at planets the Voyagers have visited, as well as the planets' gravity
fields.  In concert with the Voyagers' infrared interferometer
spectrometer and radiometer instrument, the radio science experiment
additionally has determined the ratio of hydrogen to helium, the two
overwhelmingly dominant elements in the atmospheres of each of the planets. 
 
     As Voyager 2 headed into the outer solar system, its radio signal
received at Earth became fainter.  During the Neptune flyby, the
signal strength at Earth will be 1/36th of what it was when the
Voyagers flew by Jupiter.  The collaboration with ISAS will help
offset the diminished signal, Tyler explained. 
 
     During Voyager 2's closest approach to Neptune, radio science
data will be recorded at NASA's Deep Space Network station in
Canberra, Australia; at the Parkes Radio Observatory in Australia; and
at the Usuda center in Japan. 
 
     Each receiver is linked to an atomic clock which gives an
exceedingly precise time-stamp to the received radio signal. This
allows the recorded signals from all the stations to be combined later
so that they mesh closely, with the peaks and troughs of the radio
waves matching almost exactly. 
 
     The combined signal then is analyzed to yield the experiment's
science data.  Factors such as the chemistry and temperature of a
planet's atmosphere will have minute, but measurable, effects on the
signal's frequency and strength. 
 
     Tyler noted that his team studies frequency changes that amount
to only one one-hundredth of a cycle per second in a signal from
Voyager 2 being transmitted at a frequency of billions of cycles per
second.  That is similar, he said, to measuring a change in position
of 1/25th of an inch from an observing position 3 billion miles away. 
 
     "The best ear of any trained musician can detect a change of a
partial musical step, which is some number of cycles per second,"
Tyler added.  "Needless to say, the changes we study in Voyager's
radio signal are much more  subtle than that." 
 
     Opened in October 1984, the Usuda Deep Space Center is set in the
mountains of Japan's Nagano Prefecture at 4,777 feet above sea level,
some 60 miles northwest of Tokyo. 
 
     In addition to performing tracking, telemetry and commanding for
Japan's solar system missions, such as the Suisei and Sakigake
spacecraft which flew by Comet Halley in 1986, the Usuda center
supports experiments involving sounding rockets and balloons. 
 
     The Deep Space Network, which includes complexes in the
California desert and Spain in addition to the Australian site, is
managed by the Jet Propulsion Laboratory for NASA's Office of Space
Operations.  The Parkes Radio Observatory in Australia is operated by
the Commonwealth Scientific and Industrial Research Organization. 
 
     JPL manages the Voyager Project for NASA's Office of Space
Science and Applications. 

Newsgroups: sci.space
Subject: Voyager spacecraft detects radio emissions from Neptune.
Date: 18 Aug 89 22:12:37 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Paula Cleggett
Headquarters, Washington, D.C.                   August 18, 1989
 
Mary Beth Murrill
Jet Propulsion Laboratory, Pasadena, Calif.
  
RELEASE:  89-134
 
    VOYAGER SPACECRAFT DETECTS RADIO EMISSIONS FROM NEPTUNE
  
     NASA's Voyager 2 spacecraft has detected intense radio emissions
from Neptune, indicating that the planet has a magnetic field. 
 
     The discovery, made by Voyager 2's planetary radio astronomy
instrument team at NASA's Jet Propulsion Laboratory, Pasadena, Calif.,
greatly increases the likelihood that the spacecraft will discover a
wide range of interesting phenomena related to a magnetic field, such
as aurora and possible radiation-darkened ring arcs and moons. 
 
     The emissions are generated around planets by high-velocity,
charged particles as they spiral along magnetic field lines into the
planet's atmosphere. 
 
     At Neptune, "the radio emissions are very intense, very impulsive
and occur in a limited range of frequency," said Dr. James Warwick,
principal investigator on the planetary radio astronomy experiment. 
The emissions, he added, are polarized, "so we know we're dealing with
a magnetic field.  The source is not lightning.  It is related to
energetic particles interacting in a magnetic field." 
 
     A planetary magnetic field is a girdle of magnetic field lines
that surround a planet.  Such fields are thought to be generated by
fluid motion in a planet's core (molten iron in Earth's core, for
example).  Mercury, Earth, Jupiter, Saturn and Uranus have magnetic
fields, while Venus and Mars do not.  Whether Pluto has one or not is
not known. 
 
     While the Neptunian radio emissions only were confirmed today,
Warwick said that in looking back over Voyager data, the emissions
were heard by the planetary radio astronomy instrument as early as
Aug. 14.  The emissions were not immediately recognized as being
associated with Neptune, however, because their character "was so
different from what we were expecting," Warwick said. 
 
     Early analysis indicates that Neptune's magnetic field is of an
intensity similar to the magnetic fields of Earth and Uranus. 
 
     Voyager 2's close flyby over Neptune's northern hemisphere will
allow the spacecraft's complement of instruments to determine
Neptune's magnetic field structure and orientation. 
 
     As more data from the instrument is returned to Earth over coming
days, Warwick's team will be able to precisely define Neptune's
rotation - the length of its day. 
 
     Voyager 2 will come within 3,000 miles of Neptune at 12 midnight
on August 24. 
 
     The Voyager mission is conducted for NASA's Office of Space
Science and Applications by the Jet Propulsion Laboratory. 

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Re: Voyager after Neptune
Date: 20 Aug 89 16:32:23 GMT
Organization: The Internet
 
>mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@iuvax.cs.indiana.edu  
(Henry Spencer) writes:
 
>In article <[email protected]> [email protected] (Charles 
>Daffinger) writes:
>>Alternatively, if Voyager II heads out of the solar system, how much
>>longer will we be able to maintain radio contact?  Will the probe be
>>sending back information at that time, or will it be simply shut off 
>>and left to drift?
 
>There was a paper in JBIS a few years ago, by some of the Voyager people
>at JPL, addressing this.  There are several limits involved:  attitude-
>control fuel, communications bandwidth, and electrical power.  It turns
>out that the limit is electrical power.  The isotopes in Voyager's power
>packs are decaying steadily, and the power output is dropping accordingly.
>Sometime around 2010, as I recall, there is no longer enough power to
>run the "housekeeping" systems plus the four experiments that yield useful
>data in deep space, and it will be necessary to start shutting things down.
>A few years later, there isn't enough to run even the housekeeping systems
>alone, and that's it.  Barring problems, control fuel will easily last
>that long, and communications would not be a problem until rather later.
>Whether the electronics will keep going that long is somewhat of an
>open question -- both Voyagers have had non-fatal electronic failures
>already -- but there is no definite reason to think they won't.
 
    There's a rather good article in the July/August _Planetary
Report_ on just this.  (You can always read it at the library if you
don't want Carl Sagan to get the money.)  The RTGs are expected to
last until 2025 for basic spacecraft operation.  Full instrument
operations should be possible through 2000, and all fields and
particles instruments should be operable through about 2015. Hydrazine
will last until 2025 or longer (answering my own question within these
bytes a while earlier), attitude control will lose track of the Sun
around 2030, and Voyager can be tracked by 34-meter anntenas through
2015 and past 2030 with 70-meter antennas.  So if the money is
available, there should still be something worth spending it on
through 2025.  Considering how much hydrazine is left, I have a hard
time understanding why it should even run out by 2025, since any
attitude adjustments necessary to find Earth should be minuscule at
those distances. Are they planning to spin the thing around a bit? 
 
    Peter Scott ([email protected])

    
    	Not to interrupt the postings, but Neptune FINALLY made the news.
    	
    	I'm really surprised that this hasn't gotten much press coverage,
    	especially the discovery of 3 new moons. Thank God for this
    	conference.
    
    	/prc

    Re: .50
    	For the past couple of weeks I have been seeing daily updates of
    the Voyager's mission on CNN. For this past week CNN has been showing
    live updates daily during their 5:00 ET news show and approximately
    every other day during their 8 and 10 ET news shows. I believe that
    these broadcast will become daily this week owing to the increase in
    mission activity (only 3 days to go!). CNN is also scheduled to show a
    one hour program on the flyby this Saturday night (August 26) but I
    cannot recall the time.
    	These live updates are pretty light on scientific detail but at least I
    was able to learn of the discovery of the 3 newest moons, the ring
    arcs, and the magnetic field before the more detailed information was
    posted here. In addition they display the most recent photos of Neptune
    (and last Friday of Triton). If nothing else interesting is on the
    electron bombardment tube, it is worth seeing.
    
    				Drew
    

    According to the NY Times some PBS station will be carring the
    Voyage live broadcast from Neptune.   PBS WHYY TV Philadelphia is one, 
    and 188 members stations will start from midnight Thursday
    EST to 7AM EST Friday... PBS offical said that of th e30 largest
    stations 25 are planning to broadcast the program including WNET Ch 13
    NY.  I will call up and see in the Boston PBS station will be on
    if not maybe if enought of us call they will.
    
    
    John
    
    

    WGBH TV Boston will be have NASA Select from
    0100 to 0645 EST Friday
    
    jb
    

    For you people who gives us rom's these reports a big THANK YOU!
      I can't tell you how much I enjoy reading these reports,.
                                             Bill-

Newsgroups: sci.astro
Subject: Re: Neptune on television.
Message-ID: <[email protected]>
Date: 20 Aug 89 04:54:12 GMT
Reply-To: [email protected] (Mike Northam ext 2651)
Organization: FPS Computing, Beaverton,OR
 
    From the Aug. 20-Aug. 26 issue of _On Sat_ (a satellite TV guide):
 
    CNN Covers Voyager Mission
 
    CNN Continues its commitment to live coverage of space missions
with "Voyager 1:  The Final Encounter," which chronicles Voyager 2's
passage by the planet Neptune.  CNN Began on July 31st to telecast
daily live segments from NASA's Jet Propulsion Laboratory in Pasadena,
California. Featured were interviews with mission specialists, project
managers, scientists, and astronomers, including famed scientist Carl
Sagan.  The reports, interviews, and live pictures from Neptune will
keep viewers informed of the latest discoveries about the planet as
the 12-year-old Voyager makes its closest approach at 4:00 am [PDT, I
think] on Friday, August 25, which CNN will air live. 
 
    CNN correspondent Dan Blackburn will be in Pasadena reporting on
the latest pictures and developments from Neptune and its moon,
Triton.  He will be joined by CNN Science Correspondent Charles
Crawford, who has done extensive reporting on the space program. 
 
    CNN has covered the launch of every space shuttle, as well as the
launch of France's Ariane rocket, the Soviet space station, and
Voyager's last encounter with the planet Uranus in 1986.  The coverage
of Voyager's rendezvous with Neptune is the most extensive the network
has given to any space development.  Reports air daily at 8:00 pm (ET)
through Monday, August 28, with additional reports airing at 5:00 pm
that started Monday, August 14. 
-- 
Mike Northam             [email protected]          Home:123 13'W   45 37.5'N
(503) 641-3151 x2651     {tektronix}!nosun!fpssun!mbn
*FPS Computing has a company spokesperson, and it's certainly not me*

From: [email protected] (Mike Northam ext 2651)
Newsgroups: sci.astro
Subject: Re: Neptune on television.
Date: 20 Aug 89 05:00:50 GMT
Reply-To: [email protected] (Mike Northam ext 2651)
Organization: FPS Computing, Beaverton,OR
 
    From the August 20-26 issue of _Satellite TV Week_, a satellite tv guide:
 
    "NASA to Air Neptune Flyby
 
    This week, satellite TV viewers will be able to see images of
Neptune from the Voyager 2 spacecraft flyby.  NASA coverage will be
carried on F2/13 and F5/21. 
 
    The satellites will provide program transmissions August 21
through August 29 from NASA;s Jet Propulsion Laboratory (JPL) in
Pasadena, Calif. Daily programming will begin at 9 a.m. [PDT] and
continue through approximately 5:30 p.m.  Coverage will be expanded on
August 24 when Voyager is nearest to Neptune. 
 
    Recent Neptune images received from Voyager 2 indicate weather
changes around the planet are extremely dynamic.  Voyager 2 cameras
now show large white clouds moving rapidly around and away from the
recently discovered massive dark spot.  In addition, a new moon has
been discovered by JPL scientists.  The moon measures about 120 to 400
miles in diameter. [VOYAGER 2 has discovered four new moons as of 
August 21.]
 
    The NASA television transmissions will be hosted by Dr. Albert
Hibbs and other JPL scientists.  Status reports will be provided
hourly and will include interviews and presentations by mission
scientists.  Neptune encounter briefings are scheduled daily at 10
a.m. and will include more formal scientific presentations."  
-- 
Mike Northam             [email protected]          Home:123 13'W   45 37.5'N
(503) 641-3151 x2651     {tektronix}!nosun!fpssun!mbn
*FPS Computing has a company spokesperson, and it's certainly not me*

From: [email protected] (Peter E. Yee)
Newsgroups: sci.space
Subject: Voyager Trajectory Correction Maneuver for 08/21/89 (Forwarded)
Date: 21 Aug 89 17:28:12 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
               Trajectory Correction Maneuver
                        Aug. 21, 1989
  
     Trajectory Correction Maneuver B20 (TCM B20) is the last
course-change maneuver to target the spacecraft at the desired point
of closest approach, approximately 4,850 kilometers (3,000 miles)
above Neptune's northern hemisphere at about 9 p.m. PDT on Aug. 24. 
 
     TCM B20 is designed to nudge Voyager 2 slightly to the right and
increase its velocity by just 0.470 meter per second (1.1 miles per
hour).  The maneuver will place the spacecraft 171 kilometers (91
miles) farther away from Neptune than it would otherwise be headed;
this will put Voyager 2 some 708 kilometers (439 miles) closer to
Triton than it otherwise would have been when the spacecraft passes
that moon at approximately 2 a.m. PDT on Aug. 25. 
 
     For controllers at JPL, the maneuver will start at 8:14 a.m. PDT
Monday, Aug. 21, although the event will have actually started at the
spacecraft 4 hours, 5 minutes and 24 seconds earlier -- the time it
takes for Voyager's radio signal to reach Earth.  The maneuver itself
takes 1 hour and 40 minutes, but planners had earlier allotted a
5-hour window in the spacecraft's scheduled activities to execute a
longer course change had it been needed.  Signals from the spacecraft
due on Earth at 2:30 p.m. should confirm that the trajectory
correction was successfully completed. 
 
     TCM B20 will not use Voyager's trajectory correction hydrazine
jets, but will instead rely upon the spacecraft's attitude control
thrusters to accomplish a series of four rolls of the spacecraft to
accomplish the required course change.  The slight lateral motion
imparted to the spacecraft by the rolls will result in the desired
trajectory correction while keeping the spacecraft's radio antenna
pointed at Earth.  The maneuver allows Voyager controllers to remain
in contact with the spacecraft throughout the exercise, and permits
early resumption of normal spacecraft activities after the course
correction. 

    Any Aussies monitoring this conference who might know if the encounter is
    being covered by TV here?  (I'm at OZ DECUS...)
    
    Thanks,
    
    Burns
    

Oz TV coverage of space events is almost nonexistant. Or was, but I doubt it 
has changed. 

I think one of the networks carries CNN after normal programming ends, i.e. in 
the wee hours of the morning. One of them carries some NBC news and the 'Today'
show overnight (maybe the same one).

gary

    Hey quick question,
    
    I thought these two voyager spacecraft were supposed to do a grand
    tour of all the outer planets. Now am I correct that Voyager 1 changed
    course to do some experiment at Saturn that changed its orbit to
    leave the solar system? Now second question...a friend and I were
    musing can they (the controllers) point either of the spacecraft
    to look at Pluto? It would seem that whatever Voyager could see
    has to be better than what we can see from earth?
    
    Fred Mudgett

    	VOYAGER 1 was diverted above the ecliptic plane of the Sol
    system after its study of Saturn's largest moon, Titan, and 
    cannot be diverted towards Pluto.  For VOYAGER 2 to be sent on
    a "slingshot" course to Pluto, it would have to be directed 
    almost through the center of Neptune!  Needless to say, we will
    have to wait for a future mission to explore Pluto.
    
    	Larry
    

Newsgroups: sci.space
Subject: Voyager Briefing Summary (Forwarded)
Date: 22 Aug 89 01:00:03 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
    PUBLIC INFORMATION OFFICE
    JET PROPULSION LABORATORY
    CALIFORNIA INSTITUTE OF TECHNOLOGY
    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
    PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
  
    BRIEFING SUMMARY                                  August 21, 1989
 
     NASA's Voyager 2 has detected radio emissions from Neptune with a
16-hour period, which can be explained most simply as the rotation
period of Neptune's interior, Dr. James Warwick said today. 
 
     "In a large, liquid planet with strong winds, the interior
rotates significantly differently from surface features," Warwick
said, so the interior rotation period is the best indication of the
length of its day. 
 
     The 16-hour period is 1 hour, 52 minutes less than scientists had
expected for Neptune, the last planet that Voyager will visit. 
 
     Voyager 2 photographs of the planet show a dynamic, constantly
changing atmosphere with large and small "spots" reminiscent of the
atmosphere of Jupiter.  The largest, called the "Great Dark Spot" by
mission scientists, reminds them of the Great Red Spot on Jupiter. 
 
     "It is about the same proportion to the planet's size; it is at
the same latitude, and it may be slightly redder than Neptune," said
Dr. Bradford A. Smith, Voyager imaging team leader.  "That doesn't
mean it's red," Smith said, "but that it's not as blue as the rest of
the planet. 
 
     "Neptune is an extremely dynamic planet, with less than 50
percent of Jupiter's energy," Smith said. 
 
     Images of the planet show bright clouds in the atmosphere that
Smith said "are reminiscent of cirrus clouds on Earth." They appear to
be at extremely high altitudes, so high that the methane in Neptune's
atmosphere doesn't cause them to appear blue.  The planet's blue color
is caused by absorption of longer wavelengths of light by methane. 
Some bright clouds disappear over time, which Smith said indicates
that they may be rising and falling, rather than disappearing. 
 
      Images of Neptune's largest satellite, Triton, appear to show
surface features that rotate at about the same rate as Triton's
expected 5.88-day orbital period.   Triton is smaller than had been
estimated from Earth-based observations.  "Triton has been shrinking
as we approached," Smith quipped, "until we feared that by the time we
arrived it might be gone.  It will surely turn out to be between 1,380
and 1,400 kilometers radius." 
 
     Earlier this morning, Voyager 2 performed the final
trajectory-correction maneuver of its 12-year, one-day flight. Project
Manager Norm Haynes said the maneuver was designed to trim up
Voyager's 2's trajectory for the time when the spacecraft disappears
behind Triton, as seen from both Earth and the Sun. 
 
     "We had no safety concerns," Haynes explained.  "Before the TCM,
Voyager would have performed the Earth occultation, but not the Sun
occultation.  Now we'll do both."  Haynes said the maneuver, which
altered Voyager 2's speed by about 1/2 meter per second, changed its
direction more than its speed. 
 
     Dr. Edward C. Stone, Voyager project scientist, described
calculations that scientists have performed that indicate the big
satellite could have been liquid for as much as 1 billion years of its
history.  That could have happened, Stone said, if Triton had been
captured by Neptune as it passed close to the planet. 
 
     NASA launched Voyager 2 on Aug. 20, 1977, two weeks before its
twin spacecraft, Voyager 1.  Both flew past Jupiter and Saturn, and
Voyager 2 encountered Uranus in 1986, on the way to the Neptune
encounter, which prompted Stone to characterize this flyby as "the
final movement in the Voyager symphony." 
 
     The Voyager Mission is conducted by JPL for NASA's Office of
Space Science and Applications. 

Newsgroups: sci.astro
Subject: Re: Neptune on television.
Date: 21 Aug 89 20:27:10 GMT
Reply-To: [email protected] (R. H. Ginns)
Organization: Naval Ocean Systems Center, San Diego
 
    In the San Diego area, those who are serviced by Cox cable will be
able to see "live" receptions from 10 to 11:30 A.M. daily. The Reuben
Fleet Space Theatre will also be having the real-time JPL transmissions 
projected on a screen in the lecture hall for viewing free of charge. 
This will be done daily from 9 A.M. to 8:30 P.M. except for Thursday 
when the theatre will be open all night to allow the public to see the 
CPA shots and those of Triton that will be coming in at 6 A.M. 

        According to Monday's edition of THE BOSTON GLOBE, coverage of 
    the VOYAGER 2 mission to Neptune will be shown in the Boston area 
    as follows:

        "Neptune All Night" - WGBH (PBS-TV, Channel 2) will have live 
    broadcasts of the VOYAGER 2 encounter on Thursday, August 24 from 
    1 to 7 am EDT.        

         This will probably occur with other PBS stations across the 
    U.S. and possibly Canada.

         Also, on Sunday, August 27, Sidney Poitier will join Carl Sagan 
    in a televised special called "Voyager: Rendezvous With Neptune", on 
    cable superstation WTBS from Atlanta, Georgia from 10 to 11 p.m. EDT.  

         Larry 

    Coverage for the public is sparse but does exist. Given that the
    signals for the 'close encounter' are being received at Parkes and
    Tidbinbilla in Australia before being sent to JPL, we should be
    leading the world in interest but we're not!
    The following is the coverage I know about, as of early PM, August
    23, AEST:-
    The National Broadcaster, the ABC have a special coverage 'nominally
    "live" ' commencing at 19:30 AEST on Friday August 25. The programming
    schedule is as follows:
    	19:30 Quantum Special Duration: 30 min. (That's right, only
    						30 minutes)
    	20:28 15 min. Update
    	22:25 Late Night News - will include neptune as a news item.
    
    NB: This programming will be broadcast in Adelaide for you OZ DECUS
    types. The Quantum program goes to air nationally so the time in
    Adelaide will be 19:00. (Which is 19:30 in Sydney).
    
    I also understand that coverage will be "live" at the following
    locations:
    Telecom Australia, cnr George and King Streets, Sydney City Time:?
    Powerhouse Museum, Harris Street, Ultimo, Sydney 10:00-17:00
    Ballarat TAFE, Victoria Time: ?
    
    Mind you, I believe that the last three are direct feeds from JPL
    via NASCOM and not from one of the US TV affiliates (CBS?) as I
    presume the ABC TV coverage is.
    
    I have not heard of anything else but I assume that there is more.
    I'll post what I find but would welcome other additions.

    
    	I get to put a note in here ! -
    
    	The news today on Radio 4 reported that neptune has a
    	ring, a complete ring which is 30 miles in thickness.
    
    
    	I would also like to thank Larry and other contributors for 
    	putting the information into this note.  In the UK coverage 
    	of this event is sparse.
    
    	I am going to miss looking at this note for the next discovery
    	made.  
    
    
    	Chris

Last night I found that CSpan 1 had a JPL press conference on from before 9:30pm
EDT until about 10:20pm. I found it flipping channels. Anyone know if they'll be 
covering more of these?

    Can anyone (I'm sure everyone) tell me does voyager 1 & 2 have
    recordings incase it reaches intellegent life? and also what is
    on the recordings or can anyone point me to a note on this?
                               Bill-

    Yes there  is a recording, it is a talking book type record.
    
    I think the talking books were apx 16 1/3 RPM, and it includes
    direction on how to spin it at the right rate (based on the
    hydrogen atom) and a needle to listen to the recording.
    
    I think the recording is 90 min long and has a sample of all
    the music on the earth.  There are also photos of people/places on
    the earth, but only paper dolls were allow for the ones
    showing sexual reproduction.   (they did not want to 
    offen ET, more likly a Congress person)  It is rumored
    that the Kiss sound was the producer kissing the forhead of
    Carl Sagen wife.
    
    The record was rejected just before launch as it did not
    meet specifications.  It seems the last grove had an 
    inscription on it simular to what the rock groups were
    doing at that time...   Carl Sagen save the day and
    got them to ok the record.
    
    A record was used as it would out last most anyother kind
    of recording.   
    
    You may want to contact you local PBS radio station as they
    just did a special on this very subject, they may be able
    to point you to when it will be repeated or where to find
    more information....  
    
    
    
    jb
    

RE:   <<< Note 532.66 by NRADM::COLLETON "magicians do it with their hands!" >>>

I have a book at home about the Voyager record.  I don't recall its name;
I'm sure Voyager is in the title, and the (principle?) author is Carl Sagan.
Check a local library.
						-- Tom

    I believe COSMOS, by Carl Sagan, also has a brief description of
    what's on board Voyager.  I have a tape of the recording down in
    MD.
    
    			Steve

    The name of the book (indeed authored by Carl Sagan) is called 
    "Murmurs of Earth".  It pretty much covers everything your looking for-
    (i.e.; a complete record of what music, images, sounds and greetings
    are on it).  It also does an excellent job detailing how decisions were
    made concerning the "instuctions" on the cover, and how to communicate
    the concepts of scale (i.e.: How do we show them how "big" a tree
    REALLY is...), or music, or numbers - really fascinating stuff.  Good
    luck and I hope you find a copy!  (I believe its Random House
    Publications...)   -Mike

    Guys, 

    I really don't know about this stuff, all I feel Sagan has done is to
    make some future treasure hunter very rich.  I've got to believe that
    the voyagers and pioneers are 99.99% likely to be picked up by HUMANS. 
    
    Soon, maybe 100 years, we will have drives that can go FAST, like 100's
    of miles per second.  It will then be open season on these outer space
    primitive relics.  
    
    Today people pay 100X-10000X the silver weight for Spanish galleon
    silver, in the future, I don't doubt that some collector or another
    will pay a fortune for a voyager.

    Tony
                                     

    	I do not see how the VOYAGER records will make anyone rich,
    certainly in a financial sense.  Sending a true starship out to the 
    VOYAGERs (or PIONEERs, which each carry plaques) will not be an
    easy or cheap undertaking, especially in the early years of
    interstellar exploration.  If humanity ever does wish to pick up
    the PIONEERs or VOYAGERs, they will wait until star travel is 
    much easier, and that will be a long time from now.  The records
    will then serve as valuable time capsules for our descendants,
    but the value will go beyond money.
    
    	As said before, for those interested, please read the 1978
    Random House publication, MURMURS OF EARTH, which wonderfully
    describes the VOYAGER records.
    
    	Larry
    

  I think I have to agree with Tony on this. One hundred years may be a little
soon but in about 300-400 years, when the Voyagers are only 2%-3% from here to
the next star, someone from Earth is going to zip out and pick them up. I'm
sure lots of collectors from the 24th or 25th centry would love one of these
old travellers. 

  After all, it wouldn't be that hard for them to replace them with a copy
which would make the voyage while the originals came home. 

  George

    	I just do not see anyone in the relatively near future (up to
    500 years from now) bothering to send an entire interstellar expedition
    just to pick up a PIONEER or VOYAGER.  Our descendants *might* do 
    this if the probes happen to be on their flight path to an intended
    star system, but considering how vast space is, I find this doubtful.
    
    	Also, I hope the probes are left alone, not only as tributes to
    the early days of space exploration (and as humanity's first starships,
    albeit in a very primitive sense), but for their main purpose:  To
    serve as messages from Earth to any alien civilization which finds them.
    
        If our descendants ever do find the ancient probes, I hope they
    will accord them the honor of being placed in a museum or other
    proper place of respect.  I do *NOT* want to seem them plundered
    and used like those scavengers who comb old sailing vessels simply
    to get rich off the gold.
    
    	Larry
    

    Back to the primary Voyager function.
    
    I heard in yesterday's CBS evening news that Voyager II had discovered
    another ring around Neptune.
    
    Gil

    Re: .59
    	Some more information for a reply a ways back; the original Grand
    Tour of the planets was scraped in the early 70's because it was felt
    that it was too expensive. It was to involve the launch of four
    spacecraft between 1977 and 1979. One pair of spacecraft would go to
    Jupiter, Saturn, and Pluto while the other pair would go to Jupiter,
    Uranus, and Neptune.
    	After the Grand Tour was cancelled, NASA suggested sending three
    less sophiticated spacecraft to at least Jupiter, Saturn, and Uranus.
    The chances of a less complex spacecraft surviving long enough to reach 
    Neptune or Pluto were thought to be slim. A pair of spacecraft was 
    called Mariner Jupiter/Saturn and the last one was called Mariner
    Jupiter/Uranus. Eventually Mariner Jupiter/Uranus was killed and
    Mariner Jupiter/Saturn was renamed Voyager.
    	It was recognized from the start that the two Voyagers could
    complete the original Grand Tour provided that the spacecraft could
    survive that long. But there was great interest in having one of the
    Voyagers make a close flyby of Titan. Such a flyby required that the
    spacecraft take a course by Saturn that made a flight to additional
    planets impossible. Eventually it was decided to send Voyager 1 for the
    Titan flyby. If Voyager 1 was successful AND Voyager 2 was in good
    health, Voyager 2 would be retargeted so that it could fly on to Uranus
    and maybe if they were lucky the spacecraft would survive an
    unprecidented 12 years for a flyby of Neptune.
    	The rest is history...
    
    				Drew
    

    THANK YOU Mike, FOr the info on that book I'm going to look it
     up in the library.
     
    
    
    Thank you again Larry For posting the updates on Voyager.
                                   Bill-

    Note .62 said that WGBH channel 2 would have coverage of VOYAGER
    from 1 to 7 am this morning (Thur). I get WGBH on the Nashua NH
    cable, but I stayed up until 2:30 am and nothing was on the channel.
    Was it covered by WGBH but the cable company did not put it on 
    the cable or is it tomorrow morning (Fri). If it is the cable company,
    then I will give them a nasty call. I got to watch the rebroadcast
    of the 11pm news on several stations and it bothered me that a baseball
    story (Pete Rose) was the lead story but the Voyager discoveries
    were just a short filler later in the shows.
                                               Bill
                                           

    Re:.78
    	The WGBH broadcast is suppose to happen very early Friday morning
    starting at 1:00 AM. I think some confusion arose because some consider
    "early Friday morning" to be "late Thursday night". I know that various
    TV listings seem to.
    				Drew
    

Newsgroups: sci.space
Subject: Voyager Briefing Summary for 08/22/89 (Forwarded)
Date: 22 Aug 89 22:27:12 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
    PUBLIC INFORMATION OFFICE
    JET PROPULSION LABORATORY
    CALIFORNIA INSTITUTE OF TECHNOLOGY
    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
    PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
  
    BRIEFING SUMMARY                              August 22, 1989
 
    The first complete ring around Neptune has been discovered in
images sent to Earth by Voyager 2, Dr. Brad Smith said today. 
 
    The existence of a ring that completely encircles Neptune
surprised scientists, because repeated observations from Earth have
failed to see ring material on opposite sides of the planet at the
same distance.  Those observations led scientists to speculate that
portions of rings, or "ring arcs," were responsible for the
Earth-based findings. 
 
    The new ring is so diffuse, observers on Earth would be unable to
see it, Smith, leader of Voyager's imaging team, explained. 
 
    The new ring appeared in a series of images sent to Earth early
this morning, and scientists are still trying to process the data to
extract more information.  "We can't tell much about the ring yet,"
Smith said.  "When we get behind Neptune and can look back toward the
Sun, we'll have the benefit of forward scattering of sunlight by the
individual ring particles," he explained. 
 
    "We can't tell how large or small the particles in the ring are,
or how wide it is, now, because it is so faint," Smith said. 
 
    The new ring lies just outside the orbit of the newly discovered
satellite provisionally called 1989N3, about 53,200 kilometers (33,000
miles) from the center of Neptune. 
 
    Neptune itself, meanwhile, continues to put on a meteorological
show for scientists at the Jet Propulsion Laboratory.  Dr. Edward C.
Stone, Voyager project scientist, said the spacecraft's ultraviolet
spectrometer will search for auroral activity (like the northern and
southern lights of Earth) near Neptune's south pole. 
 
    Streaks of bright, white clouds continue to race across Neptune's
bluish atmosphere.  Methane is responsible for Neptune's bluish hue,
and it hides clouds at lower altitudes, while those higher in the
atmosphere are bright. 
 
    Weather forecasts made by Voyager's atmospheric specialists "
still have some problems, but they are accurate enough that we're
giving them thumbs up," Smith said. 
 
    Smith showed photographs of Neptune's largest satellite, Triton,
which showed a mottled surface in a variety of pinkish hues.  "We
won't be able to understand Triton's surface until we get close enough
to resolve geological details," he said. 
 
    Voyager 2 will make its closest approach to Neptune about 9 p.m.
(PDT), Aug. 24, 4,500 kilometers (3,000 miles) above the clouds. 
Closest approach to Triton will occur about five hours later. 
 
    The Voyager Mission is conducted by JPL for NASA's Office of Space
Science and Applications. 

From: [email protected] (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space
Subject: Time Urgent: Voyager on TV networks and satellites
Date: 22 Aug 89 21:55:00 GMT
Sender: [email protected]
Organization: The Internet
 
    Here's news from NASA that just popped up on the CANOPUS bulletin
board (God bless Bill Taylor and the American Institute for
Aeronautics and Astronautics). It gives the times and dates for NBC,
CNN, and PBS coverage of the Voyager thing. 
 
    By now all readers of Space Digest/sci.space/whatever should be
aware that you can get the direct feed on any satellite dish.  The
more enterprising ones (such as myself in Chicago and Pat Reiff in
Houston) have persuaded their local museums or universities to open
their doors so the public can look over JPL's shoulders this week as
Neptune looms.  I've been plugging this thing on local talk shows,
saying that it's like standing on the deck of the *Santa Maria* as the
New World appears on the horizon... 
 
    Just in case you missed it, the satellite information is:
 
    GE Satcom F2R                    Aurora 1
    Transponder 13                   Transponder 6
    72 W. Long.                     143 W. Long.
    3960 MHz, vert. polar.           3820 MHz, hor. polar.
 
    Show this to a pal who has a satellite dish, and say you'll drop
over Thursday night.  If you don't know anyone with a dish, bake some
brownies and get a cold sixpack of beer.  Then drive around the
suburbs of your town looking for dishes.  Offer to trade brownies and
beer for a glimpse of Voyager. 
 
    If your time is limited, the best thing to do is watch or tape the
daily press conferences at 10 AM Pacific Daylight Time (scheduled to
last 90 minutes). Friday's and Saturday's should have particularly
spectacular news.  Perhaps the best thing of all to tape is the Final
Science Summary press conference on Tuesday the 29th at 10 AM PDT. 
 
    I'd be interested to know (by e-mail, please) how you fare if you
try any of this. 
 
    Oh, yeah.  Chicago-area people should come to Scitech in Naperville
((312)355-2299), Harper College, Cernan Earth and Space Center, Adler
Planetarium, or Governor State University to see Neptunian video.
==========================================================================
    TV Schedule for the Voyager Neptune Encounter - can890816.txt - 8/22/89
 
    HERE'S THE BROADCAST SCHEDULE FOR PUBLIC AFFAIRS EVENTS ON NASA
SELECT TV.  ALL TIMES ARE EASTERN.
 
    TUESDAY, AUGUST 21 THROUGH FRIDAY, AUGUST 25:
 
    DAILY COMPREHENSIVE COVERAGE OF THE VOYAGER 2 ENCOUNTER WITH
NEPTUNE CONTINUES TODAY WITH HOURLY ON-SITE REPORTS AND NEWS BRIEFINGS
FROM THE JET PROPULSION LABORATORY IN PASADENA, CALIFORNIA.  COVERAGE
WILL RUN FROM 12 NOON TO 8:30 P.M. WITH EXTENDED COVERAGE ON AUGUST
24.  TRANSPONDER 13 ON SATCOM F2R AND TRANSPONDER 21 ON AURORA 1. 
 
    ALL EVENTS AND TIMES ARE SUBJECT TO CHANGE WITHOUT NOTICE.
 
    Non-Satellite TV:
 
    TV viewers can see the first pictures of Voyager's flyby of
Neptune when NBC airs a special bulletin at 4 a.m. EDT Friday. That's
when the first images are expected to reach Earth from the spacecraft.
The network will run a longer report on "Sunrise" from 6 a.m. to 6:30
a.m. EDT. 
 
    *  CNN has 10-minute live reports daily from JPL at 3 p.m., 5
p.m., 8 p.m. and 10 p.m. EDT.  Other reports Friday:  1:30 a.m. and
5:30 a.m. EDT.  On Saturday, at 8 a.m. EDT, CNN anchor Lou Waters
hosts an hourlong special, "Voyager: The Final Encounter." 
 
    *  PBS plans coverage from between midnight Thursday and
7 a.m. EDT Friday.
=====================================================================
 
                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [email protected]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: HIGGINS%[email protected]

From: [email protected] (Kendall Auel;685-2425;61-028;;pooter)
Newsgroups: rec.ham-radio,sci.space
Subject: Re: deep space dishes
Date: 23 Aug 89 00:51:22 GMT
Organization: Tektronix, Inc., Wilsonville, OR
 
    In article <[email protected]> [email protected]
(Phil R. Karn) writes: 

>My references are at home, but from a description of the coding technique
>(Golay coding combined with convolutional coding) I suspect that the
>Eb/N0 required at the detector is something like 3 dB. So there must be
>8 dB of extra performance coming from a combination of antenna gain and/or
>front end improvements.
 
    Today's issue of EE Times has a front page story on Voyager titled
"Smart engineering lets Voyager keep on trackin'", by Richard Doherty.
Some excerpts: 
 
	"...the X- and S- band signals from Voyager are at this
	 point attenuated to 10(-14)W and take four hours and six
	 minutes to reach Earth."
 
	"NASA programmers have been able to tweak Voyager's on-board
	 computer and instrumentation and conserve dwindling steering-
	 rocket resources by uploading carefully crafted software
	 routines via 100-kW transmitters.  The effort has demanded
	 patience, since transmissions are held to a miserly 16 bits
	 a second."
 
	"Southern skies
	 --------------
	 JPL flight controllers have also been fine-tuning Voyager's
	 trajectory for months to make sure that its busiest period
	 of transmission comes when signals can be tracked by installa-
	 tions in the southern hemisphere, which have the best reception.
	 As a result, the setup in Canberra, Australia, has a twelve-
	 hour window onto both Voyager's 8,415-MHz X-band and 2,295-MHz
	 S-band downlinks."
 
	"Those transmissions will be sent at 21.6 kbits a second, the
	 speediest data rate possible with an acceptable signal-to-noise
	 ratio.  Transmissions from Uranus were sent at the same speed,
	 a fraction of the data rate from Jupiter."
 
	"After Australia, a 230-foot antenna in Spain will pick up the
	 data stream, which will be stepped down to 14.4 kbits/s.  Then,
	 the 230-foot Goldstone dish in the Mojave Desert, in California,
	 will track Voyager in tandem with the 27 80-foot dishes that
	 make up New Mexico's Very Large Array.  Linking the two install-
	 ations electronically will make it possible to transmit at the
	 faster 21.6 kbit/s."
 
	"Japan will also get into the act with its Usada Radio Observatory."
 
	"Tying together the whole DSN system are synchronized terrestrial
	 and satellite data links that ensure all the data is received
	 in phase.  Local recording will furnish backup and parallelism,
	 particularly valuable if some portion of the relay fails."
 
	"Voyager shipped data from Jupiter across 500 million miles at
	 115.2 kbits/s, but the greater distance to Neptune has made it
	 necessary to drop the transmission rate.  NASA wrote more
	 efficient Error-Correcting Code to support the 21.6-kbit/s
	 peak.  Without ECC, data rates could drop to 8.4 kbits/s, less
	 than half the picture potential." [...]
  
Kendall Auel                       |  [email protected]
Tektronix, Inc.                    |  P.O. Box 1000, m/s 61-028
Visual Systems Group               |  Wilsonville, Oregon 97070
Interactive Technologies Division  |  (This message composed on a TEK w/s)

Newsgroups: rec.ham-radio,sci.space
Subject: Voyager link calculations
Date: 24 Aug 89 03:33:46 GMT
Reply-To: [email protected] (Phil Karn)
Organization: Secular Humanists for No-Code
 
    Here's another link calculation for Voyager 2 at Neptune. I got
some more precise figures, and the result looks pretty reasonable. My
references to "Yuen" are to the book "Deep Space Telecommunications
Systems Engineering", edited by Joseph H. Yuen and published by Plenum
(ISBN 0-306-41489-9). 
 
8415 MHz transmitter power		+11.04 dBW
   (12.7 W - low power mode ref Yuen):
3.7 m spacecraft antenna gain
   (ref Yuen p 4):			+48.13 dB
EIRP:					+59.17 dBW
 
Path loss, 4.416e9 km, 8415 MHz:	303.85 dB
   = 20 log10(4*pi*d*f/c)
 
Receive signal flux:		       -244.68 dBW
 
70m receive antenna gain:		+73.8 dB
   = 10 log(4*pi*A/lambda^2) - N
   lambda = C/8415e6 = 3.56cm
   (assuming N = 2 dB illum loss)
 
Receive signal power:			-170.88 dBW = 8.16e-18 W
						    = 8.16 attowatts
						    = 8.16 nano nano watts
 
Received energy per bit (Eb):		-214.22 dBJ = 3.78e-22 J
   at 21.6 kb/s (43.34 dB-b/s)			    = .000378 attojoules
						    = 0.378 piconanojoules
 
Receive noise density (N0):		-218.60 dBW-Hz
   = 10 log10(kT)
   T = 10 Kelvin (ref USENET)
 
Eb/N0 ratio:				4.38 dB
 
    This is quite consistent with the performance of the concatenated
rate 1/2 Reed Solomon + rate 1/2 convolutional coder, which according
to Yuen (p 255) has a very steep "wall" or threshold just below 3 dB. 
 
    However, this figure does not take into account miscellaneous
losses (connectors, feedlines, etc) on board Voyager or at the
receiving site, nor does it allow for atmospheric absorption or
transmitter degradation below the nominal 12.7 watt figure. 
 
    According to an interview carried tonight on NASA select, the
arraying of the VLA to Goldstone effectively doubles the aperture of
the receiver, so this should give another 3 dB of margin to compensate
for these factors. 
 
    As you can see, attention to detail is all-important here!
 
    Phil

From: [email protected] (Clayton Cramer)
Newsgroups: rec.ham-radio,sci.space
Subject: Re: deep space dishes
Date: 23 Aug 89 17:09:30 GMT
Organization: Optilink Corporation, Petaluma, CA
 
    My copy of _Mariner_Jupiter_Saturn_77_Mission_Test_And_Telemetry_
System_Software_Planning_Document_ (before they changed the name to 
Voyager) dated May 18, 1976, shows: 
 
    Three high rate streams:
 
        one at 57.6 KBPS, &
        two at 1200 BPS, &
        ESP input at 16 BPS.
 
    One low rate stream at 40 bps, &
    two high rate streams:
 
        one at 57.6 KBPS, &
        one at 67.2 KBPS, &
        ESP input at 16 bps.
 
    My vague recollection was that the 1200 bps stream was engineering
and general science data, and the 57.6 kbps stream was general science
and imaging data.  (Everything was mixed together in the most peculiar
arrangements, which required software to separate the various types of
data out -- which is what I did -- badly -- on that project). 
 
Clayton E. Cramer {pyramid,pixar,tekbspa}!optilink!cramer
A pacifist who calls the police isn't one; hired violence is still violence.
----------------------------------------------------------------------------
Disclaimer?  You must be kidding!  No company would hold opinions like mine!

    re: note 78
    see note .53 but its friday not thursday that WGBH will
    be retransmitting live Voyager coverage....
    
    yes when does night become the next day...
    
    john
    

    Re: PBS coverage...
      Better a day early than a day late. I can sill use the same tape.
    

  I watched the NASA program from JPL last night on Cablevision A31.
Most of the time you get the real time feed from Voyager in black
and white. I guess that's the only choice since the color pictures
have to be calculated and combined after they are collected.

  At about 8:00 they came on with a 1/2 hour program where a TV
host interviewed several project members. The longest time was given
to a meteorologist who discussed clouds and storms on Neptune. They
talked about the dark spots and other features and talked about how
surprised they were to see that Neptune was so much more active than
Uranus.

  One interesting thing they talked about where the white cirrus type
clouds in the upper atmosphere of Neptune. They believe that they are
made up of Methane. He said that Jupiter also had Methane in the upper
atmosphere but that since Jupiter was much warmer, the Methane did
not condense into a white cloud.

  The pictures of Titan looked a little fuzzy but are beginning to show
features. They are still not sure if they are looking at clouds or ground
features.

  George

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager Neptune update
Date: 24 Aug 89 19:34:54 GMT
Organization: The Internet
 
    Extracted without permission from NASA's _Voyager Bulletin_,
Mission Status Report No. 91, August 17: 
 
    [...] Bright, wispy "cirrus-type" clouds overlie the Great Dark
Spot (GDS) at its southern margin and over its northwest boundary. 
This is the first evidence that the GDS lies lower in the atmosphere
than these bright clouds, which have remained in its vicinity for
several months.  [...] 
 
    [...] Neptune's coordinates on August 24 will be [R.A.] 18h 42m,
[DEC] -22 deg 11 min, magnitude 7.9.  
 
    Highlights of the Near-Encounter Phase

    Most of the high-value science Voyager 2 will gather during the
entire 4-month encounter period will come during a 53-hour period
spanning August 24, 25, and 26. 
 
    By then, Neptune will completely fill the wide-angle camera's
field of view (55.6 x 55.6 milliradians), which looks at fifty times
more viewing area than the narrow-angle camera (7.5 x 7.5 mrads). 
Triton [...] will fill half the narrow-angle camera's field of view. 
 
    Near the start of the near-encounter sequence, the 70m antenna in
Canberra will transmit to the spacecraft a precise tone at the X-band
frequency (about 8400 MHz).  The tracking stations near Madrid will
then listen to Voyager's return signal more than 8 hours later [...]. 
[Doppler shift will yield Neptune's gravity.] 
 
    Every 6 minutes, the low-energy charged partice detectors will
collect high-rate samples of the flow directions of charged particles
in Neptune's (expected) magnetosphere. 
 
    About 11 hours before Neptune closest approach (N-11h), Voyager 2
will take its best picture of Nereid, which will span less than 20 pixels 
in the narrow-angle frame (Neptune was this size in January 1989). 
 
    From N-10h to N-8h, the infrared instrument will be trained on a
spot in Neptune's atmosphere at -40.4 deg south latitude.  This is the
latitude Voyager's radio signal will pass through as the spacecraft
reappears rfom behind the planet at the end of its Neptune
Earth-occultation experiment, 55 min after Neptune closest approach. 
Using this data, scientists can later determine the helium abundance
at this occultation egress point, as it is called.  [...] 
 
    After imaging, infrared, and photopolarimetric observations of
Neptune's sunlit limb (edge), Voyager will next train its cameras on
the ring-arc region.  Between N-7h 17m and N-6h 22m, two retargetable
ring-arc observations will employ for the first time a clever
technique called Nodding Image Motion Compensation (NIMC) to "freeze"
the motion of selected clumps of orbiting ring-arc material.  (NIMC
"nods" the spacecraft just enough to track the target but not enough
to break the antenna's line of sight to Earth, thus allowing the data
to be returned to Earth as it is taken, rather than recorded onboard
the spacecraft for later playback to Earth.)  Between the two ring
observations, Voyager has been reprogrammed to shutter four images of
the recently-discovered moon 1989N2. 
 
    By N-5h 18m, a photopolarimetric and ultraviolet scan of Neptune's
bright limb will b completed.  Ring observations will continue for
almost 2 more hours.  Between N-4h 55m and N-3h 3m, the sensitive
detectors in the photopolarimeter and ultraviolet spectrometer will
gaze at the star Sigma Sagittarii (also known as Nunki) as it appears
to drift behind the right-hand half of the ring-arc system as a result
of Voyager's motion.  This stellar occultation may provide detailed
ring-arc region structural and orbital data. 
 
    While the bright limb scans and stellar occultations are taking
place, Voyager 2 will be receiving updated instructions from Earth. 
All of the science observations between about N-3.5h and N+9h are
sequenced in three separate movable blocks that can be shifted in
time.  The Neptune Movable Block (NMB) contains the spacecraft's
instructions for all activities around Neptune closest approach from
N-3h 20m to N+1h 46m; the Triton Movable Block (TMB) contains the
observations around Triton closest approach from N+1h 50m to N+8h 38m;
and the Vernier Movable Block (VMB) encompasses the critical sequence
for controlling the Neptune radio science occultation from N-5m to
N+56m. The VMB overlies the NMB. 
 
    By allowing the entire block of activities in each block to shift,
timing updates can be applied to the whole set in one simple step,
instead of changing individual timing parameters in each observation. 
Shifts in multiples of 48 seconds are possible for the NMB and TMB;
for the VMB, a special technique will allow shifts in radio science
occultation events of a little as one second, independent of how much
the NMB is shifted.  The success of the radio science measurements is
dependent upon the Navigation Team's ability to estimate the time of
closest approach to within one second.  For everything except the
critical radio science occultation, 48 seconds would be good enough. 
 
    By N-3h, another retargetable ring-arc observation will be
finished.  The best image of Triton before Neptune closest approach
will be taken; Triton will subsequently be eclipsed by Neptune's
southern limb, and won't be visible again until the spacecraft arcs
over Neptune's pole.  The scan platform will shift back to Neptune for
some imaging, infrared, and photometry measurements.  The Low-Energy
Charged Particle (LECP) instrument will switch into a higher-energy
sampling mode as Voyager 2 penetrates the deepest part of Neptune's
magnetic field and radiation belts.  [...] 
 
    At N-1h 41m, the sensitive optics of the instruments on the scan
platform wil be pointed away from Neptune -- towards deep space -- to
protect them from possible pitting during the inbound ring-plane
crossing.  Then, one hour from its aiming point, Voyager 2 will
configure its radio transmitter for the ring-arc system and Neptune
occultations, calibrate its antenna, and gather baseline
pre-occultation data until N-20m. 
 
    For about 10 minutes centered around N-56m, the spacecraft will
cross the ring plane just outside the ring-arc region.  The plasma
wave instrument should pick up the sounds of microscopic (harmless)
ring particles vaporizing as they hit the spacecraft. 
 
    Immediately after the ring-plane crossing, the spacecraft will
roll 61 degrees from the lock star Canopus to orient the fields and
particles instruments for measurements of the charged particles that
should be raining into Neptune's north pole along the magnetic field
lines, perhaps causing auroral activity. At the end of this roll, the
spacecraft's attitude will be under the control of the onboard gyroscopes. 
 
    Last-minute "shoehorning" has enabled the flight team to insert an
instruction to Voyager 2 to shutter a high-resolution image of the
recently-discovered moon 1989N1 about 45 min before the closest
approach to Neptune.  By a stroke of luck, the image can be taken
during a radio science antenna pointing maneuver, which provides
almost perfect image motion compensation.  Details as small as 2.5km
across should be visible [...]. 
 
    At N-5m, the duration of each of Voyager's thruster pulses will be
increased from .004s to .010s, just in case Neptune's atmosphere
applies some unexpected drag on the vehicle, and also to provide
quicker response to maneuver commands needed for the occultation
experiment.  This special provision will remain in place for the next
hour.  The shift of the VMB will precisely control the timing for all
occultation activities for the next hour.  Since the telemetry stream
will have been turned off an hour earlier to concentrate power in the
pure radio signal, all spacecraft telemetry during this time will be
routed to the tape recorder for later playback. 
 
    Voyager 2's speed relative to Neptune is expected to peak at an
impressive 98,350 km/h (60,980 mph) [at closest approach] a mere
4400km (2730mi) about Neptune's sensible atmosphere, and only 4900km
(3000mi) about the methane cloudtops below.  As it arcs over 77
degrees north latitude, the spacecraft will start to slow down, and
begin its permanent journey down and out of the ecliptic plane. 
 
    With its pure-tone transmissions still turned on -- and while
completely out of view from the Earth -- the automated spacecraft will
perform an amazing string of 24 maneuvers, collectively known as the
"limbtrack" maneuver, to precisely point the boresight of the
spacecraft's high-gain antenna along Neptune's limb, starting with the
ingress point in Neptune's northern hemisphere, then around the left
limb (as viewed from Earth), and ending with the egress point at -40.4
deg south.  The limbtrack maneuever will take about 48 min.  The radio
signals will be refracted as they pass through Neptune's atmosphere,
and the limbtrack maneuver will control the pointing of the antenna to
ensure that these signals are bent so that they hit the Earth and,
thus, the waiting antennas in Australia and Usuda, Japan.  [Yields
info on atmosphere.] 
 
    [At the same time it will] take a series of three wide-angle
images of the ring-arc system in forward-scattered sunlight.  [This]
will employ a new image smear reduction ploy called Maneuverless IMC. 
Instead of moving the entire spacecraft smoothly to track the target,
only the scan platform will be moved.  [Interesting -- I thought that
it was virtually crippled after Saturn.]  Although the platform's
motion is somewhat jerky, this technique will still afford clearer
images than if no attempt were made to track the target. 
 
    As the spacecraft emerges from behind Neptune at N+55m 8s -- again
watching with the ultraviolet instrument -- it will see the Earth
first, followed by the Sun 49 seconds later.  Voyager 2 will continue
to point its antenna at Earth for the outbound ring occultation, and
will take an edge-on shot of the ring-arc system as the spacecraft
descends across the ring-plane at N+1.5h.  [...] 
 
    [...]  About two hours past Neptune, the spacecraft will roll to a
new lockstar, Alkaid, primarily to orient the charged-particle
instruments for magnetospheric measurements between Neptune and Triton
while, at the same time, preserving good viewing of Triton [...]. 
 
    For the next 8 hours, Voyager will train its infrared,
ultraviolet, photopolarimetric, and imaging instruments on Triton. 
The 3 highest-value imaging observations from this period promise to
be among the sharpest set of pictures Voyager 2 has ever returned. 
Features as small as 1km (0.62mi) across are expected to be resolved
near the time of closest approach to Triton (N+5h15m) 
 
    By this time, Triton's small gravitational tug will be felt by
Voyager, allowing scientists on Earth to measure the gravitational
effects by observing changes in the radio signal.  Voyager will next
train its photopolarimetric and ultraviolet sensors on the star Beta
Canis Majoris for about 20 min, watching its brightness change as it
[passes behind Triton and its atmosphere]. 
 
    [40-min observation of Triton occulting Earth, Sun for about 3 min.]
 
    [Re-acquire Canopus and observe Triton for 2 hrs until tape
recorder nearly full; look back at Neptune.] 
 
    Peter Scott ([email protected])

    It was determined in the months after the Saturn encounter that the scan
    platform was not really jammed.  It was apparetnly suffering from lack
    of
    lubrication.  It is ok if it is not moved too fast.
    
    Burns
    

    
    	Well we have had lots of coverage in the UK 2 and 5 minutes slots
    	on news coverage, wish we had more.  Thank god for this notes
    	file...
    
    
    	Chris

    Same overhere in Holland, a couple of minutes in the news.
    
    A soccer match gets more attention, blah.
    
    I'm also very glad that I have this notesfile, great stuff, bravo.
    
    Keep it comming.
    

  I'm getting the direct feed from JPL on on cable. Voyager would have gone
past Triton 3.5 hrs ago but due to the 4 hour delay, the pictures coming in
now are about an hour or so before the Triton fly by. The pictures I see are
displayed in black and white and show incredible detail of what appears to be
the surface of Triton. There appear to be mountains, smooth areas, ridges, etc.
The flat areas seem smother than other moons see by Voyager that didn't have
an atmosphere. 

  They come on every hour and talk about data that other instruments have been
picking up. Light from stars is measured in ultra violet and infered as rings
or the upper atmosphere of Neptune appear to pass between Voyager and the star.

  The space craft seems to be working well and seems to have passed within
3,000 miles of Neptune with no problem.

  George

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Neptune update
Date: 25 Aug 89 10:01:31 GMT
Organization: The Internet
 
    Latest info from a personal viewpoint:  Ring arcs are out, rings
(with some parts fatter than others) are in.  Triton is beginning to
look like the real reason for coming here.  Interesting images showing
roughly parallel short dark streaks.  Apparently some imaging staff
claim they can see impact craters.   Speculations as to the nature of
Triton run the entire gamut of planetary satellite models.  About all
they agree on is that it appears to be one of the most unusual things
we've ever laid sensors on, and the later it gets the more likely
speakers are to confuse its name with Titan.  A color close-up and the
high-resolution terminator pictures will be recorded for transmission
about 24 hours from now. However, a series of overlapping pictures
will come back around 3:30 this morning, and if Ed Stone thinks it's
worth coming in to see them, so do I. I'm setting my NeXT to play a
rousing Japanese piece at that time, and laying my sleeping bag out in
my office.  The lab is humming. 
 
    Peter Scott ([email protected])

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Triton update
Date: 25 Aug 89 13:20:52 GMT
Organization: The Internet
 
    Well folks, Triton is one weird satellite.  A sequence of
clear-filter images just came in that look spectacular.  Parts of
Triton look just like the Moon; smoother, darker areas bounded by
lighter areas with very sharp and irregular boundaries, small, round,
smooth craters, some overlapping. One apparently very old crater was
just a vaguely circular wall enclosing newer craters.  The craters are
quite smooth for the most part, suggesting either an ice-like surface
or maybe atmospheric erosion.  No atmospheric features apparent,
though it would be hard to tell from just these images. Some areas
have chaotic streaking of dark matter that looks as though it overlays
the surface, much like a barbeque pit scar.  One streak appear next to
a white roud spot and looks like an ejecta blanket thrown in a narrow
fountain.  There is a giant Y-shaped feature that looks just like a
giant jeep made tracks - parallel grooves (or maybe ridges).  None of
us watching had any idea what it could be.  Near the South Pole some
evidence for the darker areas being lower than the light shows in a
series of lake-like structures enclosing dark surface.  There are long
straight ridges, mountain ranges, and a soft donut feature with no
apparent relief that we speculated could be a crater filled in over
time by ice slush. The resolution is terrific.  The color pictures of
this moon promise to be awesome. 
 
    Peter Scott ([email protected])

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Triton update
Date: 25 Aug 89 21:51:08 GMT
Organization: The Internet
 
    Well, now we're all flushed with enthusiasm from the visit of Dan
Quayle... hourly updates resume.  Atmospheric haze found over *parts*
of Triton. Possibly condensates migrating from warm to cold areas. 
The lake-like features I commented on earlier are still interpretable
as such, although the Y-shaped parallel groove tracks now look like a
single, wide Y-groove under enhancement.  Unless they happened to be
looking at a similar feature elsewhere on the moon.  Thought to be
tectonic activity; there is ample evidence of such.  Rumor in my group
is that parts of Triton have an observed albedo approaching 1... the
albedo of fresh snow is 0.8 so if this is true it is a humdinger.  I
noticed from the input histograms of the images as they arrived that
Triton is much brighter than Neptune (per unit solid angle, of
course).  Much analysis is now awaiting the arrival of the prerecorded
sequences VTCOLOR (color images of most of the moon) and VTTERM
(pictures along the terminator with a 0.8km resolution, twice what we
currently have).  Interpretation of some areas with apparent debris is
that it was thrown up from a nearby impact crater.  Several small
domes near the resolution limit spotted, one with a pit on top. 
 
    VTCOLOR and VTTERM arrive tomorrow morning.  Voyager hit the
occultation window (Triton) on the nose.  Stay tuned. 
 
    Peter Scott ([email protected])

    	For the benefit of those who have not been able to keep track of
    the latest discoveries of Voyager 2, here are some tid bits of new
    information:
    
    -Neptune's magnetic field is tilted about 50 degrees from its
    rotational axis (a similar situation exists at Uranus).
    
    -Winds on Neptune vary from about 40 mph to over 700 mph.
    
    -The two "ring arcs" discovered while Voyager 2 was approaching Neptune
    are in fact complete rings with a azimuthally clumpy distribution of
    material.
    
    -There appear to be several multi-kilometer sized moonlets imbedded in
    the clumps of one of the rings
    
    -Two additional rings were found around Neptune composed of very fine
    material. One of these appears to be about 1500 miles wide.
    
    -Two new moon were found among the rings bringing Neptune's total to 8.
    
    -The moon 1989 N1 is Neptune's second largest moon displacing Neried
    from that long held rank.
    
    -As has been seen in previous replies, Triton is at very least,
    bizzare. It was announced that Triton appears to have ACTIVE "ice
    volcanoes" or "liquid nitrogen fountains". This places Triton among Io
    and Earth as the only know currently volcanicly active bodies in the
    solar system (Venus, Mars, and Europa are "maybes" among some others).
    
    -Triton's atmosphere appears to be mainly nitrogen (like the Earth and
    Titan) and it extends several hundred miles from the surface. Methane
    was also detected (suprise, suprise) close to the surface.
    
    	There is a lot going on but this is the newest stuff that sticks in
    my mind. Stay tuned!
                                                     
    				Drew
    

	Last night on one of the cable stations was a program about
	the Voyager/Neptune flyby.   Carl "Billions" Sagan (sp?)
	talked a little about when Voyager enters interstellar space
	it will remain in orbit around the middle of the galaxy. 
	Somehow, my faulty logic indicated that the craft would 
	continue on some straight line and then exit the Milky Galaxy.
	Does that fact that the probe will end up orbiting the center
	of the galaxy have to do with the center of gravity of the
	galaxy itself?  So this means the probe will not have energy
	to escape into the inter-galatic arena? 

	/sb  

    	The PIONEER and VOYAGER spacecraft - humanity's first probes
    sent into interstellar space - will not be able to escape the
    gravitational pull of the Milky Way Galaxy, as they were given
    "only" enough velocity when launched to flyby the Jovian planets
    on a course which would subsequently take them out of our solar
    system.
    
    	It will probably be a long time from now before we send spacecraft
    out of our galaxy, as advanced techniques in exploring interstellar
    space will be needed before we can move on to other galaxies.
    
    	Larry
     

    Re: .92
    	The Voyager spacecraft (and the Pioneers for that matter) will not
    be traveling at the escape velocity of our galaxy when they leave our
    solar system. A spacecraft would have to travel at about 72 miles per
    second towards the constellation of Hercules to escape our galaxy.
    Voyager will have only about one tenth of the needed speed. The
    Voyagers will enter independent orbits around our galaxy only slightly
    different than the sun's orbit. From the point of view of our solar
    system, the Voyagers will seem to travel in a straight line away from
    us. Over the course of the next few million years the apprent path will
    become more complicated because of the changes in orbital speed as the
    sun and the Voyagers orbit the galaxy.
    	The situation is analogous to what happens when a spacecraft
    escapes the Earth. Unless the spacecraft is traveling in the right
    direction and with the needed added speed, the spacecraft will just
    enter a elliptical orbit around the Sun and not escape the solar
    system. In addition, the trajectory of the spacecraft seems to follow a
    more or less straight line for a while. Eventually the apparent path
    becomes more complicated and deviates from the initial straight line
    trajectory as the spacecraft speeds up and slows down as it travels
    around the sun.
    
    				Drew
    

Newsgroups: sci.space
Subject: NASA Headline News for 08/28/89 (Forwarded)
Date: 28 Aug 89 16:33:45 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA

-----------------------------------------------------------------
                           NASA Headline News
Monday, August 28, 1989                       Audio: 202-755-1788
-----------------------------------------------------------------
 
    This is NASA Headline News for Monday, August 28:
 
    Information gathered from Voyager 2 over the weekend indicates
that up to five rings may encircle Neptune.  The rings are seen as
thinly scattered dust particles.  Program scientists also revealed
that Neptune has a magnetic field whose poles tilt at least fifty
degrees relative to the axis around which it rotates, rather than the
thirty degrees reported earlier.   Other data indicates that the
planet's giant storm, "The Great Dark Spot," has winds up to 760
miles-per-hour. 
 
    Dr. Laurence Soderblom of the U.S. Geological Survey speculated in
a press conference yesterday that the dark spots and streaks seen
along the polar region of the Neptune moon, Triton, may be active
volanoes.  Dr. Soderblom suggested that these potential volcanoes may
be shooting plumes of liquid nitrogen twenty miles into Triton's
atmosphere.  If these findings are confirmed, Triton will become only
the third body in the solar system, behind Earth and the Jupiter moon
Io, known to have active volcanoes. 
 
    Major portions of the STS-34 Shuttle interface test were completed
yesterday, and the Space Shuttle Atlantis is slated to be moved from
the Kennedy Space Center's vehicle assembly Building to Launch Pad
39-B at midnight tonight.  The principal payload of STS-34, the
Jupiter-bound Galileo spacecraft, is slated to be placed inside
Atlantis' payload bay later this week. 
 
---------------------------------------------------------------
Here's the broadcast schedule for public affairs events on NASA 
Select TV.  All times are Eastern.......
---------------------------------------------------------------
 
    Monday, August 28 through Tuesday, August 29....
  
    Comprehensive coverage of Voyager's encounter with Neptune
continues today with NASA Select coverage from noon to 9 P.M.  A 
press conference is scheduled for 1 P.M. today. 

    Tuesday will also be the last day of coverage for the Voyager
encounter with Neptune.  Coverage begins at noon, and the mission's
final press conference is scheduled to begin at 1 P.M.  Voyager's
coverage concludes at the end of the press conference.  Transponder 13
on Satcom F2R and Transponder 21 on Aurora 1. 
 
    All events and times are subject to change without notice.
 
---------------------------------------------------------------
These reports are filed daily Monday through Friday at 12 noon, 
Eastern time.
---------------------------------------------------------------
 
    A service of the Internal Communications Branch (LPC), NASA Headquarters.

    	The latest issue of TIME magazine made one glaring error in its
    article on the VOYAGER 2 encounter of Neptune:  The spacecraft model
    they showed is of the GALILEO probe to Jupiter, not VOYAGER.
    
        I also noted that NEWSWEEK gave the VOYAGER encounter the cover
    story and devoted seven pages to the mission, whereas TIME has the
    Rolling Stones as their cover story, and only gave VOYAGER four pages.
    
    	This is why I buy ASTRONOMY and SKY AND TELESCOPE.
    
    	Larry
    

From: [email protected] (Peter Merel)
Newsgroups: sci.space
Subject: Re: Neptune on the Boobtube
Date: 29 Aug 89 07:37:50 GMT
Organization: Dept of Comp Sci, Uni of Sydney, Australia
 
    In article <[email protected]> [email protected] (Brian A.
Jarvis) writes [on errors made about VOYAGER 2 in news media]:

>In article <[email protected]> [email protected] (John Sparks) writes:
>>The answer was that in 8,000 years it will fly by Barnard's Star, in 20,000
>>or so it will pass Proxima Centauri, and then the Oort Cloud.
....
>said eventually it would be dragged back into the solar system by the
>sun's gravity and could conceivably fly by Earth again in a few centuries.
 
    You yanks don't know scientific illiteracy from Uranus.  Australia
has three commercial TV operators, all of whom seem to be in some sort
of competition to see who can make the stupidest statement about
Voyager.  My favourite so far was a guy called Brian Henderson, who's
been the anchorman on one channel here for about twenty years and is
touted as informed and respectable. He said:  "In a stunning
scientific breakthrough the latest pictures from NASA's jet propulsion
labs reveal ice volcanoes on Triton....This makes Triton the third
body in the solar system to exhibit volcanoes, the other two being
Earth itself and the jovian moon, Ten." 

 (pete%[email protected]){uunet,mcvax,ukc,nttlab}!munnari!basser.oz!pete

Did anybody record the photos from the SATCOM today at 1PM? I'd really
appreciated seeing the tape as I have no access to the program directly.

	One more question concerning the probes. Suppose, someone/something
	find the probes with their little messages about their creators.
	Are there hazardous warnings on the power units?   Isn't the power
	source of a nuclear origin?

	thanks again,
	/sb 

    Re: .99
    	First of all, you're right about the nuclear power source. There
    are, however, no warnings on the generators. Even if there were, there
    is no guarantee that they will be understood (it is proving difficult
    to design a warning symbol or pictogram for the proposed nuclear dump
    site that could be understood 10,000 years from now by humans). Chances
    are that the Voyagers (or Pioneers) will never be picked up and even if
    they were it could be tens of BILLIONS of years from now by which time
    the 50 some pounds of plutonium would have decayed to just about
    nothing.
    	But assuming they are found while the generators are still
    dangerously radioactive, look at it this way; if you were in
    interstellar space and came upon some strange looking alien device of
    unknown origin and purpose, wouldn't you check it out very carefully to
    see if it was safe? Checking for dangerous radioactivity would be high
    on my list (as well as electrical activity, physical movement, etc.)
    
    				Drew
    

re .98

I have the press conference for the 29th on tape. Contact me directly if you
are interested in borrowing it, but you won't be first in line.

They did show some really impressive '3D' of Triton's surface, and the 'Triton
movie' which is similar to the JPL 'Mars movie' but shorter. The geology team
leader commented that processing that took them 12 months at Jupiter and 
several weeks at Uranus could be done in less than 48 hours this time.

For those that are interested, they used a HyperCube system.

There was also the 'parting shot' of the crescent Neptune and Triton that was
on the news today, and some speculation on the mechanism underlying the 
'volcanoes' (thought to be liquid nitrogen phase change eruptions). And a trick
shot of Ed Stone's face in the middle of the Neptunian ring system.

re .99

Maybe the RTGs have a label that says 'The Surgeon General has determined...':-)

gary

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager update
Date: 30 Aug 89 19:49:43 GMT
Organization: The Internet
 
    Extracted from NASA's _Voyager Bulletin_, Mission Status Reoprt No. 92
   
    In some regions, Neptune's weather is perhaps as dynamic and
variable as that of the Earth.  However, the scale is immense by our
standards -- the Earth and the Great Dark Spot (GDS) are of similar
size -- and in Neptune's frigid atmosphere, where temperatures are as
low as 55 degrees K, the cirrus clouds are composed of frozen methane.
 
    Large changes can be seen in the clouds at the western end of the
GDS. A dark extension apparent in earlier images converges into an
extended string of small dark spots over the next five rotations. 
This "string of beads" extends from the GDS at a surprisingly large
angle relative to horizontal lines of constant latitude.  The large
bright cloud at the southern border of the GDS is a more or less
permanent companion of the GDS  [we've been observing it for a few
weeks and already its "permanent"?] The apparent motion of smaller
clouds at the periphery of the GDS suggests a counterclockwise
rotation of the GDS [confirmed in ABC morning news today] --
reminiscent of flow around the Great Red Spot of Jupiter.  The
activity of the GDS is surprising because the total energy flux from
the Sun and from Neptune's interior is only 5% as large as the total
energy flux on Jupiter. 
  
    Peter Scott ([email protected])

        The following address is for ordering spacecraft images and
    other reference material from the Jet Propulsion Laboratory:

	Public Relations - JPL
	4800 Oak Grove Drive
	Pasadena, CA   91109

        I hope this will be useful to those of you looking for images
    of the Neptune system from VOYAGER 2.

        Larry 

I'm very interested in picking up copies of all of the magazines that I
can find that have good coverage of the Voyager mission (especially photo's). 

I'd appreciate if people could post information on specific issues. 

	i.e.    Sept 10 Popular Astronomy, Page 50-53; text, 3 photo's
        

Also, does anyone have any more info on the computing capabilities of the
Voyager. I think it's probably very small.... making the achievement of
all involved that much more amazing.

Many thanks for all the postings..... It has been interesting watching what
has to be one of mankind's finer efforts!

Eric

    Re:.104
    	The really good magazine articles with photos of the recent Neptune
    encounter won't be out for a couple of months. "Astronomy" and "Sky &
    Telescope" should have rather extensive articles with photos and some
    preliminary analysis in their November, 1989 issues. At about the same
    time, if you are really into the "heavy stuff", "Science" should also 
    publish the preliminary science report of the mission scientists.
    Before then, weekly magazines such as "Aviation Week & Space
    Technology" and "Science News" should have some very good coverage of
    the encounter. This week's "Aviation Week..." had some excellent photos
    of Neptune and I'm sure next week's photos will be great. Finally,
    sometime in the fall of 1990, "Scientific American" should come out
    with an article (or perhaps a series of articles) with some more in
    depth analysis of the Neptune data.
    	As for Voyager's computer capabilities, I would have to do some
    digging to get specifics but I heard the computers described as being
    less capable than today's run of the mill PC both in memory and
    computing power.
    
    				Drew
                             

Re: .104

	National Geographic is also certain to come up with some pics.

Re: .105

>    	As for Voyager's computer capabilities, I would have to do some
>    digging to get specifics but I heard the computers described as being
>    less capable than today's run of the mill PC both in memory and
>    computing power.

One of the JPL people, interviewed on British TV likened the compute power
to that of a scientific calculator.

Out of interest the film shot in JPL showed a liberal sprinkling of Digital
workstations being used for image display.

jb

>532.99 "Steve Beikman"
>        Are there hazardous warnings on the power units?   Isn't the power
>        source of a nuclear origin?

Suppose when we travel interstellar space we find an alien probe.  A box jutting
from the side of it has a sign which we decipher to read "Warning:  Poison".
We then open it to find oxygen.

Regards,

David Tucker @ato

    Re:.104
    	I dug up some information regarding Voyager's computers:
    
    	There are three interconnected computer systems on the Voyagers;
    
    - The Attitude and Articulation Control Subsystem (AACS)
    - The Flight Data Subsystem (FDS)
    - The Computer Command System (CCS)
    
    	The CCS is the real "brains" of the Voyager and coordinates the
    activities of the other subsystems. It contains two redundant memories
    where command sequences (actually more like programs) are stored. Each
    memory has a 4096 word capacity of which about 2800 words are "fixed"
    routines (i.e. subroutines, functions, subprograms, etc.) and about
    1290 words of variable memory for changing command sequences. A single
    1290 word command load can easily generate over 300,000 discrete
    actions (e.g. move azimuth to 35 degrees, open narrow angle camera
    shutter for 5 time units, read narrow angle camera vidicon, and so on).
    	So overall, as a previous reply mentioned, Voyager has about as
    much memory as today's top of the line scientific calculator. Imagine
    if they sent up a VAX...
    
    				Drew
    

                  I N T E R O F F I C E   M E M O R A N D U M

                                        Date:     28-Aug-1989 06:48pm EST
                                        From:     Shel Sherman @LAO
                                                  SHERMAN.SHEL AT GOLETAA1
                                        Dept:     LAGD SALES
                                        Tel No:   213/417-4249

TO: See Below

Subject: "HAVE YOU HEARD?"

While most of us have enjoyed the brilliant and "awe-striking"
images forwarded to us from VOYAGER from billions of miles away, few
of us know that the entire image enhancement process takes place on a
4 node VAX Cluster at the Jet Propulsion Laboratory. 

This month, and especially this past week, the Field Service District, 
reporting to Aggie Rucker, has been on full alert with 7 x 24 coverage 
at the Lab.  Our efforts to prepare for, prevent and react to any 
possible contingency is one of the stories not in the press this week 
about Digital.

As Digital employees working in the government/aerospace sector, we 
can all be proud of the outstanding job being done by our Field 
Service teammates to assure that the country's space program and 
NASA's prestige continues to flourish.  one has to only imagine a 
different set of circumstances to truly appreciate this week's news.  
We can also be proud that our design engineers and our hardware 
architecture are as good as they are.  We often take this sort of 
thing for granted.  Field Service's outstanding effort can only lead 
to a better relationship with JPL and with NASA in general.

A special thanks is owed to the 24-hour-a-day effort by Field Service, 
to the competent Field Service engineers insuring a flawless 
operation, and to the Field Service District Manager, Aggie Rucker, 
who took on the risk and rsponsibility.

    THANK YOU ALL!

    Distribution: ( list deleted )

That's funny, the guy from USGS presenting the Triton images seems to think
he is using a HyperCube for image processing.

Remember, the preceeding memo was written by sales...

I'm quite prepared to believe that JPL use VAX systems for some of the image
processing.

gary

From: [email protected]
Newsgroups: sci.space
Subject: Voyager's Interstellar Itinerary
Date: 1 Sep 89 16:15:00 GMT
 
       The following is from The Planetary Report, the main publication 
   of the Planetary Society, regarding VOYAGER 2's journey through the 
   Milky Way Galaxy through the millenia:
 
  Year (A.D.)     Event
 
   8571        Closest approach to Barnard's Star - 4.03 ly away!
                0.42 ly from the Sun.

  20319        Closest approach to Proxima Centauri - 3.21 ly away.
                1.00 ly from the Sun.

  20629        Closest approach to Alpha Centauri - 3.47 ly away.
                1.02 ly from the Sun.

  23274        Closest approach to Lalande 21185 - 4.65 ly away.
                1.15 ly from the Sun.

  26262        Enter Oort Cloud.  This seems real fishy to me, especially
                since no one agrees where the Oort Cloud actually is located.

  28635        Exits Oort Cloud and Solar System officially.

 129084        Closest approach to Ross 154 - 5.75 ly away.
                6.39 ly from the Sun.

 296036        Closest approach to Sirius - 4.32 ly away.
                14.64 ly from the Sun.

 442385        Closest approach to 44 Ophiuchi - 6.72 ly away.
                21.88 ly from the Sun.

 957963        Closest approach to DM+27 1311 - 6.62 ly away.
                47.38 ly from the Sun.
 
        Personally, I wouldn't trust the numbers past about 60,000 years;
  there are still too many unknown possibilities for gravitational influences. 
 
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
|  Arnold Gill                          |
|  Queen's University at Kingston       |
|  BITNET:    gill@qucdnast             |
|  INTERNET:  [email protected]  |
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

From: [email protected] (Doug Mink, OIR)
Newsgroups: sci.space
Subject: Re: Pluto fly-by
Date: 1 Sep 89 18:53:46 GMT
 
    On Monday, August 28, R.T. Mitchell of JPL gave a talk,
"Interplanetary Trajectory Design," at a conference I was attending in
Pasadena.  He described an assortment of interesting gravity assist
maneuvers for getting to a variety of places in the solar system
ranging from solar impact to a Pluto flyby.  While the trajectory the
Pluto community has been talking about takes 17 years, JPL has come up
with Earth- and Jupiter-assisted routes that take as little as 10
years.  The problem with fast trips is that you zip through the system
too fast to study anything for very long. Some of my friends on the
Voyager team expressed the feeling that it would be OK to leave one
planet unprobed for future generations to discover.  For now, Triton
will serve as a good analog for Pluto, being of similar size, similar
distance from the sun, and possessing a similar atmosphere with a haze
layer. 
 
    Doug Mink
    Harvard-Smithsonian Center for Astrophysics
    Cambridge, Massachusetts
 
    Internet:  [email protected]
    BITNET:    mink@cfa
    SPAN:      cfa::mink
    Phone:     (617)495-7408
    FTS:       830-7408

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager update
Date: 2 Sep 89 21:54:32 GMT
 
    More on the Day-Glo blue planet and its sidekick satellite,
excerpted without permission from the JPL UNIVERSE, September 1: 
 
    [Triton:] Scientific observers said that no other single body in
the solar system contains all those terrain types. 
 
    Triton's surface appears geologically young -- "millions to
hundreds of millions of years old," [Larry Soderblom, Deputy Imaging
Team Leader] said. 
 
    Dr. Brad Smith, Voyager Imaging Team Leader, commented that "the
features that look like craters are almost certainly not impact
craters, but must be related to internal processes." 
 
    [Neptune's blue color] is caused by the absorption of longer
wavelengths of light by methane [...]. 
 
    Provocatively scattered over the giant blue globe's atmosphere are
bright clouds "reminiscent of cirrus clouds on Earth," Smith commented. 
 
    These clouds appear to be at extremely high altitudes, Smith said;
so high that the methane in Neptune's atmosphere doesn't cause them to
appear blue. 
 
    Some bright clouds disappear over time, Smith added, indicating
that they may be rising and falling rather than disappearing. 
 
    [Bow shock crossed at 11:48am PDT 8/24]  Neptune's magnetic field
is tipped 50 degrees from the planet's rotation axis [ouch], according
to data from the plasma and low-energy charged-particle instruments
 
    "We found the major component of [Triton's] atmosphere is
molecular and ionized gaseous nitrogen," reported Dr. Bill Sandel, [U
of AZ] co-investigator on Voyager's ultraviolet spectrometer.  "We
found methane at lower altitudes." 
 
    By Saturday, August 26, Voyager's photopolarimeter performed an
experiment that measured light from the star Sigma Sagittarius as it
passed behind Neptune's outermost ring, revealing more detail about
the recently found ring. 
 
    The experiment showed that the ring has a core about 17km (10 mi)
wide, and an optically thinner component about 50km (30 mi) wide. 
 
    Voyager images disclosed three more rings, according to Brad
Smith.  The two earlier rings are called 1989N1A, the outer; and
1989N2A.  One new ring, wider than those two, lies closer to Neptune. 
The second new ring orbits between 1989N1A and 1989N2A.  A third new
ring is broad and diffuse, and extends virtually from just outside
1989N1A all the way to the outer edge of 1989N2A. 
 
    Smith showed an image of 1989N1A, the outer ring, that took
advantage of Voyager's motion during exposure to reveal several 10- to
20-km-wide bodies embedded within the ring.  The bodies appear to be
separated by about 100 to 200 km (60 to 120 mi).  They may help
scientists sort out the mechanism that caused the observed structure
of the outer ring. 
 
    [Volcanoes on Triton] The geyser-like volcanic vents, triggered
from a depth of about 30m (100'), where nitrogen can exist in a liquid
state, bring up some extremely fine, dark, particles from beneath the
surface.  The winds that blow through Triton's rare atmosphere carry
them downwind before depositing them on the surface.  
 
    [Footnote:  The press has now left.  No more moments of staring at
monitor images only to turn aside to see a paparazzi snapping away,
saying, "No, go ahead, go ahead, that's great!"] 
  
    Peter Scott ([email protected])

Newsgroups: sci.space
Subject: Voyager Audio/Slide Show
Date: 4 Sep 89 16:53:28 GMT
Reply-To: [email protected] (Hiram Clawson)
Organization: The Santa Cruz Operation, Inc.
 
    Voyager "The World on a Record", contents of the gold disc: (From
page 371 of the notes for Frank Drake's class Astronomy 109 - Intelligent 
Life in the Universe) 
 
    Music (in sequence):
 
    Bach: Brandenberg Concerto #2, 1st m.
    Java: court gamelan--"Kinds of Flowers"
    Senegal: Percussion
    Zaire: "Pygmy girls" initiation song
    Australia: horn and totem song
    Mexico: mariachi--"El Cascabel"
    Chuch Berry: "Johnny B. Goode"
    New Guinea: men's house
    Japan: shekuhachi (flute)--"Depicting the Cranes in Their Nest"
    Bach: Partita #3 for violin
    Mozart: "Queen of the Night" (from "The Magic Flute")
    Georgia, USSR: folk chorus--"Chakrulo"
    Peru: pan pipes
    Louis Armstrong: "Melancholy Blues"
    Azerbaijan: two flutes
    Stravinsky: "Rite of Spring" conclusion
    Bach: Prelude and Fuge #1 in C Major
    Beethoven: Symphony #5, 1st m.
    Bulgaria: shepherdess song--"Izlel Delyo hajdutin"
    Navajo: night chant
    English 15th cent.: "The Fairie Round"
    Melanesia: pan pipes
    Peru: woman's wedding song
    China: ch'in (zither)--"Flowering Streams"
    India: raga--"Jaat Kahan Ho"
    Blind Willie Johnson: "Dark Was the Night"
    Beethoven: String Quartet #13, "Cavatina"
 
    Sounds of Earth (in sequence):

    Whales, planets (audio analog of orbital velocity), volcanoes, mud
pots, rain, surf, cricket frogs, birds, hyena, elephant, chimpanzee,
wild dog, footsteps and heartbeats, laughter, fire, tools, dogs
(domestic), herding sheep, blacksmith shop, sawing, tractor, riveter,
Morse code, ships, horse and cart, horse and carriage, train whistle,
tractor, truck, auto gears, Saturn 5 rocket liftoff, kiss, baby, life
signs: EEG, EKG, pulsar.
 
    Greetings in the following tongues(alphabetically):

    Akkadian, Amoy (Min dial.), Arabic, Aramaic, Armenian, Bengali,
Burmese, Cantonese, Czech, Dutch, English, French, German, Greek,
Gujarati (India), Hebrew, Hindi, Hittite, Hungarian, Iia (Zambia),
Indonesian, Italian, Japanese, Kannada (India), Kechua (Peru), Korean,
Latin, Luganda (Uganda), Mandarin, Marathi (India), Nepali, Nguni (SE
Africa), Nyanja (Malawi), Oriya (India), Persian, Polish, Portugese,
Punjabi, Rajasthani, Roumanian, Russian, Serbian, Sinhalese (Sri
Lanka), Sotho (Lesotho), Spanish, Sumerian, Swedish, Telugu (India),
Thai, Turkish, Ukranian, Urdu, Vietnamese, Welsh, Wu (Shanghai dial.).
 
    Pictures (in sequence):  

    Calibration circle, solar location map, mathmematical definitions,
physical unit definitions, solar sys. parameters(2), the sun, solar
spectrum, Mercury, Mars, Jupiter, Earth, Egypt - Red Sea Sinai Pen.,
Nile (from orbit), chemical definitions, DNA structure, DNA structure
magnified, cells and cell division, anatomy (8), human sex organs
(drawing), conception diagram, conception photo, fertilized ovum,
fetus diagram, fetus, diagram of male and female, birth, nursing
mother, father and daughter (Malaysia), group of children, diagram of
family ages, family portrait, continental drift diagram, structure of
earth, Heron Island (Australia), seashore, Snake River - Grand Tetons,
sand dunes, Monument Valley, leaf, fallen leaves, sequoia, snowflake,
tree with daffodils, flying insect - flowers, vertebrate evolution
diagram, seashell (Xancidae), dolphins, school of fish, tree toad,
crocodile, eagle, S. African waterhole, Jane Goodall - chimps, sketch
of bushman, bushmen hunters, Guatemalan man, Balinese dancer, Andean
girls, Thai craftsman, elephant, Turkish man with beard and glasses,
old man with dog and flowers, mountain climber, Cathy Rigby, Olympic
sprinters, schoolroom, children with globe, cotton harvest, grape
picker, supermarket, diver with fish, fishing boat - nets, cooking
fish, Chinese dinner, licking - eating - drinking, Great Wall of
China, African house construction, Amish construction scene, African
house, New England house, modern house (Cloudcroft), house interior
with artist and fire, Taj Mahal, English city (Oxford), Boston, UN
building (day), UN building (night), Sydney Opera House, artisan with
drill, factory interior, museum, X-ray of hand, woman with microscope,
Pakistan street scene, India rush-hour traffic, modern highway
(Ithaca), Golden Gate Bridge, train, airplane in flight, airport
(Toronto), Antarctic expedition, radio telescope (Westerbork), radio
telescope (Arecibo), book page (Newton's System of the World),
astronaut in space, Titan Centaur launch, sunset with birds, string
quartet, violin with score. 
 
    --Hiram  (uunet!sco!hiramc  ||  [email protected])

In a map in the "Planetary Report", it appeared that Voyager I was actually
going to pass through the general vicinity of Pluto.  Obviously on a map
of the scale that would be in a small magazine, the distance could be
millions of kilometers.  And of course the map was only 2D as well.

Does anyone have any idea how far V1 will actually pass from Pluto? 

A real pity "old number 9" could not have been visited too.

Burns

    
	I haven't seen much about the results of the Voyager flyby in the
notes and I have seen nothing in the press. As a result I figured that 
I would share some new information I recently received with some more results.

Neptune:
	- The overall temperature of Neptune is 59K (-353F) at its cloud
	  deck.
	- The period of rotation is 16 hours and 3 minutes.
	- Neptune's winds are primarily retrograde unlike the other gas 
	  giants.
	- Neptune's temperature profile is similar to that of Uranus.
	- Auroras were detected over a wide area of Neptune's atmosphere
	  and were not confined to the magnetic poles.
	- Neptune's magnetic field is tipped 50 degrees to its rotational
	  axis and appears to be offset 9,600 Km. (6,000 mi) from its center.
	- The magnetic feild strength varies from 1.2 to 0.06 gauss. 

Rings:
	- Voyager detected a total of three rings and one broad diffuse
	  ring.
	- The two main rings have a large number of small particles and 
	  resemble Saturn's Encke and F rings.
	- The main outer ring is very clumpy in places and some of the clumps
	  could be small satellites a few kilometers in diameter.
	- During Voyager's ring plane crossing, the plasma wave experiment
	  detected smoke size dust particles hitting the spacecraft at the
	  rate of 300 per second, very similar to the results from the 
	  Saturn ring plane crossing. No spacecraft damage was detected
	  as a result of the impacts.

New Satellites:
	- A total of six new moons were found by Voyager all of which seem
	  to have a reflectivity of about 2%.
	- The moon 1989N1 is Neptune's second largest moon with a diameter
	  of 420 Km. (260 mi.).

Triton:
	- Triton has a diameter of 2,720 Km. (1,690 mi.) and a bulk density
	  of 2.02 grams per cubic cm. This means that Triton has 29% of the
	  mass of Earth's moon and a surface gravity 8% of Earth's.
	- Triton's atmosphere has a surface pressure of 10 microbars (a 
	  thousandth of a percent of Earth's) and a temperature of 33K (-400F).
	  Both are MUCH lower than scientist expected. Triton is the coldest
	  body ever observed.
	- Triton's atmosphere, for some reason, reaches a peak temperature
	  100K (-280F) at an altitude of 600 Km. (375 mi.).
	- Triton appears to have no impact craters.
	- Triton displays several types of cryo-volcanism the most spectacular
	  of which appears to be a nitrogen geyser. It is theorized that
	  liquid nitrogen is trapped 20 to 30 Km. (12 to 19 mi.) below the
	  surface and that it wells up through fissures or holes in the 
	  surface. Once the pressure drops below a critical value, the liquid
	  explosively turns to gas and creates the geyser with a velocity
	  of 250 meters per second (560 miles per hour). The gas entraps
	  radiation darkened methane ice as it travels to the surface and
	  sprays it 40 Km (25 mi.) high. The winds in the rarefied atmosphere
	  then carries the particles as much as 75 Km. (46 mi.) downwind
	  causing the observed dark streaks.
	- All the observations to date do not exclude the possibility that
	  Triton was captured by Neptune and spent as much as a billion 
	  years in a molten state due to tidal interactions as its orbit
	  evolved into its present state (as a recent theory speculates).

	I have also got more information on the proposed phot of the solar
system that Voyager 2 could take. Discussions between program officials are
still taking place. If the photo is to be taken, it will be a color mosaic of 
several images and would be taken in March or April of 1990 when the planets
will be reasonably aligned.

				Drew

From: [email protected] ("Richard Johnson, CSC, Univ. of 
      Colorado,  492-3630", 303)
Newsgroups: sci.space
Subject: RAMTEK Image Explained
Date: 6 Sep 89 18:15:00 GMT
Organization: The Internet
 
MIPL     VGR-2     INTR      NEPTUNE      9663.32(1)  [ image  ]
----------------------------------------  0791N2-058  [numbers?]
|                                      |              INPUT
|                                      |      ---------------------
|                                      |      |                   |
|                                      |     [   incoming data    ]
|                                      |     [grey-scale histogram]
|              [  the  ]               |      |                   |
|              [picture]               |      ---------------------
|                                      |              OUTPUT
|                                      |      ---------------------
|                                      |      |                   |
|                                      |     [     displayed      ]
|                                      |     [grey-scale histogram]
|                                      |      |                   |
|                                      |      ---------------------
|                                      |  ZOOM - 4X4 AT 410,450
|                                      |  DC SUBTRACT ON       [notes]
|                                      |  STRETCH - MANUAL     [vary?]
|                                      |  L030=000   H070=255
----------------------------------------
INSTR = ISSNA  IMODE = NAONLY   INA = 12.28 SCALE = 617878
FILTER = 3-ORA TMODE = 1M2C     EMA = 7.83
EXP = 15.36    RANGE = 83406896 PHA = ?     183:12:39  10-JUL-1989 VAX2 RMA0
  
    A while back, Phil Karn asked for a description of "the rest of
the data" in the RAMTEK images of Neptune.  Since I haven't seen any
other replies, here's what I know.  Please, if I'm fibbing about
something, point it out, with corrections. 8-) 
 
    We'll start at the usual place for folks with some Western
European cultural heritage - the top left corner.  First is the
processing location.  Second is the name of the spacecraft that took
the picture.  Third is the system source for the image.  Here, RLTM
means real time data displayed as soon as it arrives at JPL, INTR is
the interactive image displayed from a scientist's workstation, and
RPLA is a replay for NASA Select TV of data received earlier. 
Finally, we have the name of the target body being imaged. 
 
    The stuff in the middle should be fairly self-explanatory, except
for the holes in my knowledge.  Can anyone help fill in a bit of
meaning?  The bottom is nearly as cryptic, but there I do know what
the codes mean. 
 
    INSTR is the instrument.  For pictures, there are two cameras on
VOYAGER 2: wide angle (ISSWA) and narrow angle (ISSNA). 
 
    The FILTER setting for the image can be clear, green, orange, blue
violet, ultraviolet, methane, or sodium. 
 
    IMODE indicates how the cameras were shuttered.  NAONLY means only
the narrow angle camera was shuttered.  WAONLY is (you guessed it) the
wide angle camera only.  BOTALT and BOTSIM indicate both cameras were
shuttered alternately or simultaneously (respectively).  BODARK means
neither camera was shuttered (used for calibration - unlikely to
result in an exciting image).  NOSHUT means neither wide or narrow
read out (though I'm at a loss as to the practical difference between
this and BODARK). 
 
    TMODE is the telemetry mode at which the data is read out
(compressed, slow scan, edited, and so forth). 
 
    RANGE is the distance in km between the spacecraft and the target
body center. 
 
    Now for the info that Phil was particularly interested in.  INA is
the incidence angle of sunlight at the target body.  EMA is the emission 
angle of sunlight reflected from the target body.  PHA is the phase angle 
between the incoming sunlight and reflected light from the target. 
 
    SCALE is the distance across the frame at the target body in km.
 
    Finally, we have the time and date.  The UTC time stamp for when
the data was received appears just below the SCALE in 
DayOfYear:Hour:Minute format. The other time field contains the local
date at JPL, the MIPS computer ID, and the display device ID. 
 
 | Richard Johnson                      [email protected] |
 |         Center for Space Construction, University of Colorado       |
 | Grad students don't need disclaimers - no-one listens to us anyway. |
 |             Power Tower... Dual Keel... Block One...?               |

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager update
Date: 8 Sep 89 20:13:56 GMT
Organization: The Internet
 
    Extracted from NASA's _Voyager Bulletin_, Mission Status Report No. 93,
August 27:
 
    The ring-count at Neptune stands at three or six, depending on
whether or not sheets of particles between the discrete rings are
considered rings in themselves.  [...]  [If you have seen the backlit
image of the rings formed from two images placed on either side of a
dark band where Neptune would be, then...] Two gaps in the upper part
of the outer ring in one of the images [left] are due to blemish
removal in the computer processing [same software that got rid of all
those nasty spots on Uranus before we ironed the bugs out... ;-)] 
Numerous bright stars are evident in the background.  Both bright
rings have material throughout their entire orbit, and are therefore
continuous. 
 
    Voyager 2 was designed to operate at 10AU [...] yet its reach has been
extended by a factor of three [...].
 
    Extracted from Mission Status Report No. 94, August 28:
 
    "Imagine Jupiter orbited by Mars..." -- Dr. Laurence Soderblom, Deputy
Team Leader, Voyager Imaging Science Team, in regards to Triton.
 
    Triton has something for everyone, noted Dr. Soderblom, of the
U.S. Geological Survey in Tucson, AZ: complex geology [? Tritology ?
-PJS], polar ices, complex chemistry, and hazes.  Dr. Soderblom
proposes that perhaps ice volcanoes are active even now. 
 
    The boundary betwween Triton's bright southern hemisphere and the
darker northern hemisphere is clearly visible (due to Triton's tilt
and inclined orbit, the southern hemisphere receives more direct
sunlight).  Patterns of light and dark regions cover most of the
southern hemisphere.  Also evident are long, straight lines that
appear to be surface expressions of internal, tectonic processes.
No large impact craters are visible in the southern hemisphere,
suggesting that the crust of Triton has been renewed relatively
recently -- that is, within the past billion years or so. 
 
    One "crazy idea" currently under study is that ice volcanoes are
resurfacing the moon.  About 50 dark plumes or "wind streaks" can be
seen in early evaluations of images of the southern polar terrain. 
The plumes originate at very dark spots generally a few miles in
diameter.  Some are more than 100 miles long. The spots, which clearly
mark the source of the dark material, may be vents where gas has
erupted from beneath the surface and carried dark particles into
Triton's nitrogen atmosphere.  Southwesterly winds may then have
transported the erupted particles, forming the gradually thinning
deposits seen to the northeast of most of the vents.  It is possible
that the eruptions have been driven by seasonal heating of very
shallow subsurface deposits of volatiles, and the winds transporting
particles may be seasonal winds. 
 
    The polar terrain, upon which the dark streaks have been deposited
is a region of bright materials mottled with irregular, somewhat dark
patches. The pattern of irregular patches suggests that they may
correspond to lag deposits of moderately dark material that cap the
bright ice over the polar terrain. 
 
    In Triton's northern hemisphere, there are large tracts of
peculiar terrain unlike anything seen elsewhere in the solar system
[sounds like a sensor report from Mr. Spock -PJS].  Most of the area
is covered by roughly circular depressions separated by rugged ridges.
The depressions are probably not impact craters since they are too
similar in size and too regularly spaced. Their origin is currently
unknown, but may involve local melting and collapse of the icy
surface.  A conspicuous set of grooves and and ridges cuts across the
landscape, indicating fracturing and deformation of Triton's surface. 
 
    Three irregular dark areas, surrounded by brighter material, may
be dark substrate below a bright frost cover.  Once a hole burns
through the frost, for whatever reason, the region warms and defrosts,
but a cold rim spreads around the area. 
 
    Other features include what appear to be frozen lakes or old
calderas, which have multiple floor levels, perhaps due to massive
flooding and re-freezing in a sea of ice-like lava.  In one scenario,
fluid rises on the floor of the crater and then solidifies.  The next
era of melting allows the next floor to also rise and then refreeze. 
These types of floods are probably not localized to the caldera areas
of the moon. 
 
    Triton's atmosphere has been found to be primarily nitrogen-based,
with some methane.  The atmosphere may extend as much as 800 km (500
mi) above the surface of the 2720-km (1690-mi) diameter moon.  In
addition, images show a thin haze layer extending 5 to 10 km (3 to 6
mi) above the moon's limb.  The haze may be condensation of subliming
(evaporating) materials. 
 
    A false-color map of Triton shows several compositionally distinct
terrain and geologic features [referring to a picture designated
"P-34720"].  At center is a gray-blue unit referred to as "cantaloupe"
terrain [I told you it was a hungry night for the imaging team]
because of its unusual topographic texture. The unit appears to
predate other units to the left.  Immediately adjacent to the
cantaloupe terrain is a smoother unit, represented by a reddish color,
that has been dissected by a prominent fault system.  This unit
apparently overlies a much-higher-albedo material, seen farther left. 
A prominent angular albedo boundary separates relatively undisturbed
smooth terrain from irregular patches that have been derived from
breakup of the same material.  Also visible at the far left are
diffuse, elongated streaks, which seem to emanate from circular, often
bright-centered features.  The parallel streaks may represent vented
particulate materials blown in the same direction by winds in Triton's
thin atmosphere. 
  
    Peter Scott ([email protected])

From: [email protected] (Michael D'Alessandro)
Newsgroups: sci.space
Subject: Voyager and Viking images on CD-ROM for $9!
Date: 9 Sep 89 22:36:42 GMT
Organization: NLM/LHNCBC, Bethesda, Md.
 
    TITLE:  New CD-ROM Holds Images from Voyager, Viking Missions
 
    Here's good news for astronomy buffs and galaxy gazers. Meridien
Data, maker of CD-ROM premastering systems, is offering a disc that
holds hundreds of images sent back to Earth by the Voyager and Viking
planetary probes. The $9 disc contains images that can be viewed on
either an IBM PC or a Macintosh. 
 
    However, the CD does not include recently photographed images of
Neptune, which Voyager 2 passed on its way out of the solar system.
The public-domain images on the disc are from Voyager and Viking
missions during the past 10 to 15 years, said Meridien spokesperson
Lou Hoffman. That includes images of Mars (from the Viking probes of
the late 1970s), Jupiter, Saturn, and hundreds of other shots taken by
the Voyager spacecraft. 
 
    The Voyager/Viking CD is called the GRIPS (Government Raster Image
Processing Software and Data) disc. Several government agencies,
including NASA, the Jet Propulsion Laboratory, and the National Center
for Supercomputing Applications, contributed information for the disc.
 
    Some of the images on the disc require up to 1.2 megabytes of
storage space, Hoffman said, but those aren't even close to being the
largest sent back from space. Some of the Voyager images have been as
large as 20 to 30 megabytes. 
 
    The GRIPS disc holds one set of data files that is shared by both
PC and Macintosh platforms. The disc adheres to the ISO 9660 file
format; Meridien claims it's the first CD-ROM of that format that both
PC and Mac users can access. 
 
    No documentation comes with the GRIPS CD, and Meridien admits it's
not easy to locate a specific image from among the hundreds on the
platter. "There's a front-end index on the disc, but it's difficult to
use at this point," Hoffman said. The company is working on a way to
make the disc more "user friendly," he added. 
 
    Meridien says the first pressing, of 1000 discs, is going fast and
that a second pressing of another 1000 could start in about two weeks.
"Response has been greater than we expected," Hoffman told Microbytes
Daily. In fact, the company is considering marketing a series of
CD-ROM discs with images from Voyager missions. 
 
                            --- Jeffrey Bertolucci
  
Contact: Meridien Data, 5615 Scotts Valley Dr, Scotts Valley,
CA 95066; (408) 438-3100; fax (408) 438-6816
  
Michael D'Alessandro
The National Library of Medicine
Lister Hill National Center for Biomedical Communications
Educational Technology Branch            Internet:  [email protected]

       "Life depends less on an abundant supply of energy than on a good
    signal-to-noise ratio." - Freeman Dyson
 

Newsgroups: sci.space
Subject: Voyager Status for 09/11/89 (Forwarded)
Date: 12 Sep 89 01:11:58 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
                    Voyager Status Report
                     September 11, 1989
  
     Voyager 2, now coasting beyond the planets, continues to return
data to Voyager scientists as the spacecraft looks back at Neptune and
Triton. 
 
     The spacecraft began executing the final command load of the
post-encounter phase of the Neptune mission on Sunday, Sept. 10.  The
commands will carry Voyager 2 through the end of the Neptune encounter
on Oct. 2. 
 
     Plans are underway to create what project officials are calling
"the picture of the century" -- actually a mosaic of several images of
the solar system taken by either Voyager 1 or Voyager 2 that, when
combined, will give us a never-before-seen panoramic view of our
Sun's planetary system and Earth's place in it. 
 
     Whichever spacecraft does the job, imaging for the "picture of
the century" won't begin until early next spring.  By that time, both
spacecraft's perspective on the solar system will have improved, and
instruments other than the TV cameras on Voyager 2's scan platform
will have completed their post-Neptune observations and calibrations. 
  
    DISTANCE TO EARTH:      2,784,895,000 miles
    DISTANCE TO NEPTUNE:    15,815,000 miles
    HELIOCENTRIC VELOCITY:  37,373 mph

    I'm a little curious.
    
    From what little I remember of college astronomy, it seems to me that I
    remember that Triton was a RETROGRADE satelite.  Nired (sp), the far
    smaller object was in normal rotation.
    
    We have gone through this whole incounter with little of no mention of
    this very important fact, thus I conclude that either my memory is
    faulty, or for some pecular reason the orbital orientation of Triton is
    not as important as some possible ice vulcanoes.
    
    Any help for me on which it is or is it simply that they have no clue
    why triton is retrograde?  (reminds me, there was little/no speculation
    on why Uranus was so tipped).
    
    Tony

    Re .120 
    
    Tony, I did hear it said that Triton's retrograde circular orbit was 
    one of the most puzzling things in the solar system. And that because 
    of it there could be no rings in Neptune, and ...
    
    Neptune's axial tilt was also puzzled over as well. But all this was 
    before the close encounter, I guess that, right now they are trying to
    digest all the data they got and will not say anything until they do.
    
    While writting this I asked myself, could there be any relationship
    between the two. Neptune's axial tilt and Triton's retrograde circular
    orbit. !!!!!!!!!!
    
    Gil

    	Triton's retrograde orbit has been quite a big issue during the
    whole encounter and well before VOYAGER 2; the possible ice volcanoes
    were a new and unexpected phenomenon, thus capturing more immediate
    attention from the press and scientists.  The "problem" is that before
    VOYAGER's flyby, it was "easily" assumed that Triton was an object
    captured by Neptune's gravity, but new studies have now shown that
    this theory may not be as valid as it once was.
    
        A new theory for Triton's orbit comes from the same ideas given
    for the amazing axis tilt of the planet Uranus, which also was not
    ignored:  That the early days of the solar system's formation were
    chaotic, and that Uranus may have received its 98% axial tilt when
    an Earth-sized planetoid slammed into it, knocking it over (if such
    perspectives can be used in interplanetary space where there is no
    true up or down).  Neptune also seems to have had a chaotic formation,
    as reflected in the wild orbits of Triton and Nereid.
    
        If you are relying on the general media to give you informed
    news about the Neptune encounter, you'll be better off waiting for
    the much better astronomy publications to come up with their more
    detailed and informative news on the encounter; and within a year
    or so I also guarantee that several books on Neptune will also be
    published.
    
      	Larry
    

    Re:.122
    	I completely agree with your comments but planetary formation in
    addition to being chaotic is frighteningly violent! In addition to the
    events at Uranus and Neptune, many other properties of the solar system
    are now being explained by enormous impacts late in the formation
    process. According to a recent theory, a large impact on Mercury blew
    the bulk of its crust and mantle off leaving what is essentially an
    iron core with a thin silicate veneer. The slow rotation of Venus could
    have been caused by the impact of a large body. And a recent theory to
    explain the formation of Earth's Moon requires that a Mars size body
    slamed into the Earth with the reulting iron poor debris eventually
    condensing to form the Moon. Further out there is evidence in the
    cratering records on the moons of Saturn and Uranus that some of the
    moons were shattered and then reformed possibly several time due to
    violent impacts during the formation process.
    
    				Drew
    

  I remember reading once that there may be a relation between the retrograde
orbit of Tritian and Pluto. Since the orbits of Pluto and Neptune cross, the
theory was that at some point Tritan and Pluto may have interacted in a way
that left Tritan in a Retorgrad orbit, and Pluto in a solar orbit of its own. 

  Since then I've read someone who claimed to disprove this by pointing out
that the place where Pluto crosses the orbit of Neptune does not line up
with Neptune's orbital plane.

  Someone else once pointed out that the eratic orbits of the outer planets
may be the rule and not the exception. Their theory was that the inner planets
were forced into more regular orbits because of the strong effect of the sun
and that any irregularities had been eleminated, whereas the outer planets
would be able to continue more eratic behavior due to the weak influence
of solar gravity at large distances.

  George

>  Since then I've read someone who claimed to disprove this by pointing out
>that the place where Pluto crosses the orbit of Neptune does not line up
>with Neptune's orbital plane.

This is true, for what it's worth. Pluto's orbit is inclined quite a bit to the
plane of the ecliptic (roughly the plane where all the others lie), so it
doesn't really intersect Neptune's orbit. Doesn't really disprove anything - the
same interaction could have flung Pluto out of the plane.   -Tom R.

    	The theory that somehow Pluto was ejected from the Neptunian system
    by Triton has been largely discredited now. The original theory states
    that Pluto at one time orbited Neptune until Triton came along and by
    some sort of gravitational interaction flung Pluto from the Neptunian
    system and placed Triton in its present retrograde orbit. There are
    several problems with this scenerio:
    
    - No mechanism has been found that would eject Pluto from the Neptunian 
      system AND put Triton into the present retrograde orbit.
    
    - Pluto has its own moon. There are no moons in our solar system that
      have their own moon. In addition even if there was some way to eject
      Pluto from the Neptunian system, there is no way that Pluto's moon
      would remain with Pluto.
    
    - The theory requires that Triton come into the Neptunian system from
      solar orbit to do its thing to Pluto. If we had Triton in solar orbit
      near Neptune to start, why do we even bother trying to explain
      Pluto's orbit? We are still stuck with a body orbiting near Neptune,
      which is what we were trying to explain to begin with!
    
    - In reality, because of Pluto's tilted and elliptical orbit, Pluto
      actually gets closer to Uranus than it ever does to Neptune.
    
    	All in all, this theory is pretty lame. Current thinking suggests
    that Pluto is just a small planetismal that was not incorporated into
    one of the outer planets and somehow escaped ejection from the solar
    system, but only barely. Recent simulations of Pluto's orbit over a 860
    million year period indicate that its orbit is not too stable. It is
    still possible that Pluto could be ejected from the solar system or
    collide with one of the planets over the next few billion years.
    	As for Triton's retrograde orbit, a recent theory suggests that
    Triton entered the Neptunian system very early in its formation. If it
    collided with one or more of the moons in orbit around Neptune,
    Triton's velocity would have been decreased enough to be captured by
    Neptune. The intial orbit would have been highly inclined and very
    elliptical but over the course of a billion years, tidal forces would
    have made Triton's initial orbit evolve into the presently circular
    retrograde orbit (and in the process kept Triton melted for much of the
    time). The current state of the Neptunian system as well as the
    relative lack of large impact craters on Triton seems to support this
    theory (although it is still too early to tell for sure).
    
    				Drew
    

    	Pluto is inclined 17 degrees above the ecliptic.  The only other
    planet which even comes close is Mercury, with only 7 degrees.
    
        Larry
    

Newsgroups: sci.astro
Subject: Orbital Elements for 1989 N5 and N6 (Forwarded)
Date: 18 Sep 89 20:59:48 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
[This article is made of a couple of letter's from Bill Owen of JPL.  I
 suggest you not bother him for better numbers -- he can't give them to
 you. -PEY]
 
    About a week ago I received a request for orbital elements for
1989 N5 and N6. The following is the response I received from JPL. 
I'm posting it to the net for those who are interested in such things.
 
						-Peter Yee
						[email protected]
						ames!yee
 
----- Forwarded information from Bill Owen, NASA Jet Propulsion Laboratory ----
 
    The best numbers we have at the moment are proprietary:  the
Voyager Imaging Team has rights to them for the next year.  I am
allowed to quote you approximate values, however. 
 
 Sat     Semimajor axis (km)   Period (hr)    Body radius (km)
    
 1989N1       117600              27                210
 1989N2        73600              13                100
 1989N3        52600               8                 70
 1989N4        62000              10                 80
 1989N5        50000               7 1/2             45
 1989N6        48200               7                 25
 
    All are in direct motion, basically circular and equatorial; although
1989N6 has an inclination of 4 or 5 degrees to the planet's equator.
 
    You might keep an eye out for the "30-day report" to be published
in Science around the end of the year.  The final orbital elements for
the rocks, however, won't appear until later, in the Astronomical
Journal or some such. 
  
    -- Bill Owen, [email protected] (Internet) or MUON::WMO (SPAN)

       "We have found a strange footprint on the shores of the unknown.
    We have devised profound theories, one after another, to account for
    its origin.  At last, we have succeeded in reconstructing the creature
    that made the footprint.  And Lo! it is our own." - Arthur Eddington
 

>    The best numbers we have at the moment are proprietary:  the
>Voyager Imaging Team has rights to them for the next year.  I am
>allowed to quote you approximate values, however. 
 
  ????

  Anyone have any idea why the operators of a U.S. space probe, who's
mission is scientific, and is payed for with U.S. tax dollars would sit
on the results of our space probe?

  George

    	On September 23, 1846, the planet Neptune was discovered by the
    German astronomer Johann Gottfried Galle based on mathematical and
    physics calculations by himself and other astronomers.
    
        Almost a century and a half later, thanks to VOYAGER 2, we finally
    know what Neptune and its moons really look like.
    
    	Larry
    

        Someone on USENET also asked the same question brought up in
    Note 532.129.  Here is one answer:
                
Newsgroups: sci.astro
Subject: Re: Orbital Elements for 1989 N5 and N6 (Forwarded)
Date: 25 Sep 89 14:54:43 GMT
Reply-To: gsh7w@astsun3 (Greg Scott Hennessy)
Organization: University of Virginia, Charlottesville
 
    In article <[email protected]> [email protected]
(Jesse Furqueron) writes: 
 
#What is this? Is there some inner circle owning scientific info?  Just how
#wide spread is "proprietary" info in the community as a whole? Last time
#I heard its OUR tax dollars paying for THEIR proprietary info!
 
    In order to attract top scientists to work on a project, it is
necessary to give them something they want. While money sounds like a
good offer, what a scientist wants is data. Why should a scientist
work for several years on a project, only to find when the project is
done that everyone else has used the data that was collected and
written papers while he was busy collecting the data? Thus there is a
tradeoff made. The scientists, who have given up several years of
work, get to use the data for one year to allow them "first shot" at
the papers. After one year, the data is put into public domain,
available to anyone who pays the price of a computer tape. There have
been images released already. Be patient, and the rest of the data
will become available. 
 
-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      [email protected]  
 UUCP:		...!uunet!virginia!gsh7w

From: [email protected] (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space
Subject: Time Urgent:  Voyager movies Oct 2 on satellite or tape.
Date: 25 Sep 89 22:38:00 GMT
Organization: The Internet
 
    If you've got access to a satellite dish and VCR (I don't), get
ready to tape some juicy Voyager stuff.  If not, you can buy the tape.
Here's a press release I just received from JPL: 
--------------------------------------------------------------------------
    The recently completed Neptune Encounter Highlights tape will be
transmitted over NASA-Select on Monday, October 2. 
 
    SATELLITE VIDEO SOURCE:
 
    GE SATCOM F2R*
    Transponder 13
    71 W. Longitude
    3960 MHz, vertical polarization
    C-band
 
    * Institutions that are interested in receiving the transmission
over NASA-Select but are located in Alaska and Hawaii are requested to
contact Terry Brooks at (818)354-6278. 
 
    DATE/TIME:
 
    October 2  1:00-1:29 PM Eastern Time, 9:00-9:29 AM Pacific Time
 
    If you miss the transmission, copies of this tape may be ordered
directly from our contracting video company: 
 
    The Video Tape Company
    10545 Burbank Blvd.
    North Hollywood, CA 91601
    (818)985-1666
 
    Cost: 3/4" $47.00
          1/2" $34.40
    ------------------------
    Some highlights of the tape:
 
    Computer animations:  Viewing Neptune from Triton, diving over
Neptune to meet Triton, catching Triton in its retrograde orbit,
encountering Neptune's magnetopause, close encounters with Neptune and
Triton, view from Earth of Voyager's occultation, Voyager encounters
Neptune and Triton [4:34 extravaganza, I presume one of those great
Jim Blinn encounter movies], nodding image motion compensation. 
That's the first ten minutes. 
 
    Created from actual Voyager images:  Neptune rotation movie,
Neptune approach movie, Neptune weather movies, Neptune global
rotation, real-time images, Voyager at Triton [3-d perspective],
Neptune's rings, Neptune's atmospheric features, Neptune's atmosphere
in motion, the Great Dark Spot, flight over Triton [3-d perspective],
a farewell. 
=====================================================
 
                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [email protected]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: [email protected]
 

Date:     Wed, 27 Sep 89 17:26 CDT
From: Bill Higgins-- Beam Jockey <HIGGINS%[email protected]>
Subject:  Time Urgent: Mistake (was: Time Urgent: Voyager movies on Oct. 2.) 
To:       [email protected]

    A couple of days ago I posted information about a Voyager Neptune
video sequence that will be broadcast Monday, October 2, on NASA
Select (Satcom F2R, transponder 13, 71 degrees West longitude,
vertically polarized).  I carefully checked all the numbers before I
posted the item, because I didn't want to introduce any errors. 
Unfortunately, there was ALREADY an error in the JPL press release. 

    The sequence will be broadcast at 1 PM Eastern time, 10 AM
(**not** 9 AM!!) Paci fic time.  It will last for 29 minutes.  I
apologize for letting the mistake get past me. 

                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [email protected]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: [email protected]

    	The October issues of ASTRONOMY and SKY AND TELESCOPE magazine
    have some preliminary articles on the VOYAGER 2 encounter with 
    Neptune.  The information is good, but there is really nothing 
    there that anyone who had followed the mission hasn't seen before.
    
    	Larry
    

Newsgroups: sci.space
Subject: Geyser-like plume discovered on Neptune's moon Triton (Forwarded)
Date: 9 Oct 89 05:27:57 GMT
Reply-To: [email protected] (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
 
Charles Redmond
Headquarters, Washington, D.C.                    October 2, 1989
 
Mary Beth Murrill
Jet Propulsion Laboratory, Pasadena, Calif.
  
RELEASE:  89-156
 
    GEYSER-LIKE PLUME DISCOVERED ON NEPTUNE'S MOON TRITON
  
     A 5-mile-tall, geyser-like plume of dark material has been
discovered erupting from the surface of Neptune's moon Triton in
images returned last month to the Jet Propulsion Laboratory, Pasadena,
Calif., by NASA's Voyager 2 spacecraft. 
 
     The discovery comes just as the Neptune encounter -- Voyager 2's
fourth and final planetary flyby in 12 years -- officially ends today,
Oct. 2. 
 
     This is the first time geyser-like phenomena have been seen on
any solar system object, other than Earth, since Voyager discovered
eight active geysers shooting sulfur above the surface of Jupiter's
moon, Io.  The new finding -- Voyager's last hurrah in its journey
past the planets -- augments Triton's emerging reputation as the most
perplexing of all the dozens of moons Voyagers 1 and 2 have explored. 
 
     Voyager 2's camera captured the eruption shooting dark particles
high into Triton's thin atmosphere.  Resembling a smokestack, the
narrow stem of the dark plume, measured using stereo images, rises
vertically nearly 5 miles and forms a cloud that drifts 90 miles
westward in Triton's winds. 
 
     While Voyager scientists are trying to determine the mechanism
responsible for the eruption, one possibility being considered is that
pressurized gas, probably nitrogen, rises from beneath the surface and
carries aloft dark particles and possibly ice crystals.  Whatever the
cause, the plume takes the particles to an altitude where they are
left suspended to form a cloud that drifts westward. 
 
     Voyager 2's working life among the planets may be at an end, but
the spacecraft and its twin, Voyager 1, are expected to continue
returning information about the various fields and particles they
encounter while approaching and eventually crossing the boundary of
our solar system.  The plutonium-based generators that provide
electricity to the spacecraft are expected to keep alive the
computers, science instruments and radio transmitter for up to 25 or
30 more years. 
 
     As of today, the long-lived project will be known as the Voyager
Interstellar Mission.  The Voyager Project is managed for NASA's
Office of Space Science And Applications by the Jet Propulsion
Laboratory, Pasadena, California. 

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager Update
Date: 11 Oct 89 23:17:35 GMT
 
    Extracted from NASA's _Voyager Bulletin_, Mission Status Report
No. 95, October 2: 
 
    A five-mile-tall, geyser-like plume of dark material has been
discovered erupting from the surface of Neptune's cold moon Triton in
images returned last month by Voyager 2. 
 
    The discovery comes just as the Neptune encounter [...] officially
ends today, October 2. 
 
    [...] Surface temperatures on Triton have been measured to be
about -390 F, and the terrain is among the most varied seen anywhere
else in the solar system. 
 
    Voyager 2's camera captured the eruption shooting dark particles
high into Triton's atmosphere.  Resembling a smokestack, the narrow
stem of the dark plume, measured using stereo images, rises vertically
nearly 8 km (5 mi) and forms a cloud that drifts 150 km (90 mi)
westward in Triton's winds. 
 
    While Voyager scientists are trying to determine the mechanism
responsible for the eruption, one possibility is that pressurized gas,
probably nitrogen, rises from beneath the surface and carries aloft
dark particles and possibly ice crystals.  Whatever the cause, the
plume takes the particles to an altitude where they are left suspended
to form a cloud that drifts westward. 
 
    The dark plume was first discovered in stereo images taken by
Voyager 2.  The image [shown here, pity you can't see it :-)] was
taken on August 24 from a distance of 99,920 km (62,000 mi).  The
image shows the geyser-like colum nearly in profile, since the
spacecraft was only 16 degrees above the horizon as seen from Triton's
surface at the base of the plume. 
 
    As of today, the long-lived project will now be known as the
Voyager Interstellar Mission [just what we need... some VIM... pjs]. 
 
    Peter Scott ([email protected])

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Neptune update
Date: 20 Oct 89 18:36:07 GMT
 
    Extracted from NASA's _Voyager Bulletin_, Mission Status Report No. 96,
October 4:
 
    NEPTUNIAN METEOROLOGY
 
    Although Neptune receives only 1/900th as much energy from the Sun
as Earth does, it reemits about three times this amount - an indication 
that heat is being generated in Neptune's interior and radiated to space.  
Scientists have long thought that the winds in a planet's cloud tops are 
driven by the Sun's heat, but now they must consider more strongly the 
contributions of the planet's own interior heat source. 
 
    Voyager's infrared observations of Neptune showed that
temperatures are warmer near the equator and south pole, and cooler in
mid-lattitudes - surprisingly similar to the case at Uranus.  Since
the south pole is tilted slightly toward the Sun at this point in
Neptune's orbit, it is not surprising that it is warm.  But the warmth
at the equator is surprising because less sunlight falls there due to
the planet's tilt.  Voyager's ultraviolet investigation measured
temperatures at high altitudes in Neptune's stratosphere at about 400
Kelvins (250 deg F), while the infrared investigation measured the
temperature at the 100 millibar pressure level to be about 55 K (-360 F). 
 
    While analysis continues, the results of the radio science
investigation seen consistent with an atmospheric chemical composition
of about 85 percent molecular hydrogen, 13 percent helium, and 2
percent methane.  The infrared investigation's results indicate that
some amount of acetylene exists as well. [God help any astronaut who
leaks any oxygen into that stuff. - PJS] 
 
    The Great Dark Spot, at about 22 degrees south latitude, is
probably at lower altitude than its accompanying bright clouds.  The
size of the [GDS] in its east-west extent is comparable to the
diameter of Earth - over 12,500 km (nearly 8,000 mi).  Time-lapsed
movies constructed from single frames show that the [GDS] is not
totally oval, has spiral arms, and appears to have a counterclockwise
circulation pattern.  Imaging scientist Dr. Andy Ingersoll of Caltech
drew chuckles with the remark that the [GDS] looks like "a great glob
of pizza dough going around".  The [GDS] circles Neptune in a little
less than 18 hours, implying that it is in an atmospheric zone with
westward (retrograde) winds of more than 300 meters per second (700
mph!).  Bright, wispy, "cirrus-type" clouds overlie the [GDS] at its
southern and northeastern boundaries. 
 
    According to atmospheric scientist Dr. Jim Pollack of NASA's Ames
Research Center, some of the bright spots on Neptune may be convective
clouds rising above the base of the methane clouds.  He suggests a
cycle of methane on Neptune wherein ultraviolet sunlight first
converts methane to hydrocarbons in the stratosphere.  The major
hydrocarbons, such as ethane and acetylene then drift down to the
colder lower stratosphere, where they evaporate and condense into
hydrocarbon ices.  These ice particles fall into the warm troposphere,
evaporate, and are converted back to methane.  The methane is returned
to the stratosphere by buoyant convective clouds, which rise to the
base of the stratosphere or higher.  The bright central core of the
southern dark spot is probably such a rising convective cloud, and the
bright cloud at about 42 degrees south latitude may be interpreted as
a cloud plume rising between the methane and hydrogen sulfide cloud decks. 
 
    As Voyager 2 approached the planet, imaging scientists were able
to track the features in the clouds to determine the wind speeds. 
They were surprised to find that some features, such as the [GDS], had
a rotation period of 18 hours, in close agreement with ground-based
observations, but that other features moved much faster.  The bright
cloud at about 42 degrees south latitude was nicknamed "Scooter"
because of its 16-hour rotation period. However, motions in the
atmosphere are indicative only of wind speeds.  The rotation of the
bulk of the planet can best be measured by studying the periodicity of
the planet's radio signals, generated by deep-seated convection
currents in the planet's interior, and carried to space along the
planet's magnetic field lines.  The Planetary Radio Astronomy Team
[PRAT?], led by Dr. Jim Warwick of Radiophysics, Inc., determined from
Neptune's radio signals that a Neptunian day is 16 hours 3 minutes. 
 
    Dr. Brad Smith, leader of Voyager's Imaging Science Team, suggests
that the clouds near the [GDS] are not moving rapidly themselves, but
that the air around them is, analogous to lenticular clouds that form
over mountains here on Earth.  As winds go through the region, they
are deflected upward where the volatiles condense out and form clouds.
 
    Voyager also saw cloud shadows in Neptune's south polar region,
the first time a Voyager spacecraft has been able to see any such
features on a planet.  The shadows are cast by methane cirrus-type
clouds that are estimated to be 50 to 75 km (30 to 45 mi) above the
haze or stratus clouds. 
  
    Peter Scott ([email protected])

RE:< Note 532.137 by RENOIR::KLAES "N = R*fgfpneflfifaL" >
>the planet's tilt.  Voyager's ultraviolet investigation measured
>temperatures at high altitudes in Neptune's stratosphere at about 400
>Kelvins (250 deg F), while the infrared investigation measured the
>temperature at the 100 millibar pressure level to be about 55 K (-360 F). 


Does this mean that there are areas on the planet above the freezing level 
of water (even above it boiling point)?  What a range of environments!

Rich

    re:.138 and having liquid and gaseous h2o
    
    Boiling and to a lesser extent melting point are not a constant, but a
    function of pressure.  Thus you could have liquid h2o at 250 F, or
    gaseous (steam), all depending upon the ambient pressure.  
    
    Tony

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager update
Date: 26 Oct 89 18:52:37 GMT
 
    Extracted from NASA's _Voyager Bulletin_, Mission Status Report No. 97,
October 16:
 
    MAGNETICALLY, NEPTUNE IS MUCH LIKE URANUS
 
As Voyager 2 closed on Neptune, the bets were that Neptune would have a
simple magnetic dipole roughly aligned with the planet's rotational axis
and centered within the planet.
 
Six of Voyager's instruments measure fields and particles.  The first of these
to sense the planet is usually the planetary radio astronomy (PRA) subsystem,
which detects planetary radio emissions.  These radio signals result from 
dynamo electrical currents generated deep in a planet's interior and carried
to space along the planet's magnetic field lines.  Charged particles near the
planet arre trapped within an imaginary "cage" formed by the magnetic field
lines and are swept along as the planet rotates.  All seemed quiet in the 
fields and particles domain until August 17 (PDT) when the PRA began to
detect signals from Neptune.  From the intervals between the signals, the PRA
team deduced that the rotation rate of the bulk of the planet is about 16 
hours -- much shorter than the 18-hour period deduced from tracking cloud
features in the atmosphere.
 
The next fields and particles event, the bow shock crossing, occurred on
August 24.  During interplanetary cruise, the spacecraft is in the solar wind
where particles travel at supersonic speed near one million miles per hour.
At the bow shock, the solar wind flow is slowed to subsonic speeds, heated,
and deflected by interaction with the planet's magnetic field.  Prior to
crossing the Neptune bow shock approximately 35 Neptunian radii from the
planet's center (about 865,000 km or 537,000 mi), measurements by the plasma
science instrument indicated that the solar wind temperature was 6,300 kelvins,
but the density was only 0.0045 protons per cubic centimeter.
 
Within the magnetosheath, the temperature rose dramatically to about 250,000 K
and the density to 0.03 protons per cc.  Inbound to Neptune, Voyager 2 was in
the magnetosheath for about 25 minutes before crossing the planet's
magnetosphere at about 22 Neptunian radii (about 500,000 km or 300,000 mi)
from the planet's center.
 
The magnetic field did not behave as expected, nor was it even _where_ it was
expected.  Expecting a magnetic axis roughly aligned with the rotational axis,
the fields and particles investigations were geared for an unusual opportunity
to directly detect particles spiraling into Neptune's north polar atmosphere
along magnetic field lines as Voyager 2 passed near the planet's north pole.
However, Dr. John Belcher, principal investigator for Voyager's plasma science
investigation, announced on August 25 that from their data, his team inferred
a magnetic dipole tilted 50 degrees from the rotational axis -- surprisingly
similar to the 59 degree tilt of Uranus' dipole.  (Earth's dipole is titled
11 degrees from the rotational axis.)
 
Rather than the expected crossing near the confluence of the magnetic field
lines, Voyager 2's path had carried it for the first time through a relatively
high-latitude cusp of a planetary plasma domain and then into a more nearly
equatorial region of the magnetosphere, allowing observations within the
magnetosphere for about one-and-a-half planetary rotations.
 
In addition, Dr. Norm Ness, principal investigator for the magnetometry
investigation, reported that Neptune's field is not a simple dipole.  (An
example of a simple dipole is a child's bar magnet.)
 
The low-energy charged particle (LECP) investigators, led by Dr. Tom Krimigis,
reported sensing a tremendous number of protons, as well as helium, carbon,
and hydrogen in Neptune's magnetosphere.  The LECP team also reported that
in the range from 28,000 to 43,000 electronvolts, they found an increased
population of energetic protons inside the orbit of Triton.  They measured
temperatures about 700 million degrees Celsius (over 1.3 billion degrees
Fahrenheit) and a density of 0.00025 per cc.  The probable source for these
hot plasmas is Neptune's ionosphere.
 
The LECP team also reported that Voyager 2 had passed over a magnetic polar
area after all, yielding the first direct detection of auroral zone particles
impacting the atmosphere of a nonterrestrial planet.  Their initial estimates
of the auroral power was greater than 1 million watts (Earth's auroral power,
which we see as the Northern or Southern Lights, is about 100 billion watts).
Because of the tilt and offset of the magnetic field, Neptunian auroras might
be expected to occur near the equator rather than at the poles, but because of 
the complex structure of the magnetic field near the planet, auroral activity
is probably widespread.
 
In summary, the quick-look analysis of Voyager's pass through Neptune's
magnetosphere indicates that Neptune looks very much like Uranus, magnetically.
The dipole is tilted 50 degrees from the rotational axis, and magnetic north
is in the southern hemisphere.  In addition, the magnetic pole is offset by 2/5
(0.4) of Neptune's radius (Uranus's magnetic pole is offset by 1/3 [0.3] 
Uranian radius.) The magnetosphere undergoes dramatic changes as the planet
rotates and the moons orbit.  The dipole moment (the mean field strength at
the 1-bar pressure level) is 0.13 gauss R_N^3, but because of the large offset
the strength of the field ranges from 1.2 to 0.06 Gauss (Earth's surface field
is about 0.3 Gauss).  The large variation in field intensities indicates that
dynamo electrical currents may be much closer to the "surface" (the 1-bar
pressure level) of Neptune than was true for Jupiter or Saturn.
 
In terms of the density of charged particles in the planet's magnetosphere,
Voyager's magnetosphere is the emptiest encountered by Voyager.  The large
tilt and offset apparently allow the satellites and ring particles to
effectively "sweep" charged particles out of the magnetosphere.
  
    Peter Scott ([email protected])

Newsgroups: sci.space,sci.astro
Subject: Voyager 1 Update
Date: 1 Nov 89 22:46:06 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                      Voyager 1 Update
                      27 October 1989
 
     NASA restored full contact with Voyager 1 after the space probe
stopped sending data to Earth this week--the first such malfunction
since it was launched in 1977 to explore Jupiter and Saturn. 
 
     "We're relieved, of course.  But now there's the question of why
did it happen and is it going to happen again?"  said John Tullius,
senior mission controller for Voyagers 1 and 2 at NASA's Jet
Propulsion Laboratory. 
 
     Controllers never lost Voyager 1's "carrier signal," a single
tone that allows them to track the probe's location, which is now
above the plane of the solar system some 3.7 billion miles from Earth.
But sometime between 6 a.m. and 4 p.m. PDT October 23, Voyager 1
stopped sending its "telemetry signal," which transmits scientific
data collected by the probe and information about how the spacecraft
is functioning, Tullius said. 
 
     At noon on October 24, engineers sent commands to reset Voyager
1's "telemetry modulation unit," ordering it to start working again.
The commands took 5 1/2 hours to reach the spacecraft, and the same
amount of time for Voyager to confirm the commands worked. It was
after 11 p.m. on the same day when engineers knew full contact was
restored, Tullius said. 
 
     Although engineers at times have shut off Voyager telemetry
signals intentionally, this week's partial loss of contact was the
first time it has happened accidentally.  The cause is under
investigation, but Tullius said a cosmic ray may have hit the
telemetry unit, or a circuit simply malfunctioned because of age.  
 
 Ron Baalke                       |    (818) 541-2341 x260
 Jet Propulsion Lab  M/S 301-355  |    [email protected]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

>The cause is under
>investigation, but Tullius said a cosmic ray may have hit the
>telemetry unit, or a circuit simply malfunctioned because of age.  
    
    What the heck does "a cosmic ray may have hit the telemetry unit" mean?
    That sounds like something a TV news anchor would say.
    
John

    Re: .142
    	When cosmic rays pass through semiconductor components they can
    redistribute the charge in a device (for example making a logic switch
    change state) or even destroy the device outright by disrupting its
    lattice structure. The statement "a cosmic ray may have hit the
    telemetry unit" seems to imply that a comsic ray hit some how jumbled up
    the logic circuit in the telemetry unit which is used to send data from
    the spacecraft back to Earth. As a result, the unit was not operating
    in the proper mode (if at all) and it needed to be reset thus erasing
    the cosmic ray induced logic error.
    
    				Drew
    

I was really impressed with that 3.7 billion miles until I
realized that the article also said that it took several hours
for the radio waves to transit...and that distances to the stars
are measured in light years!  We're just learning to crawl,
aren't we?

From: [email protected] (Bill Wyatt)
Newsgroups: sci.astro,sci.space
Subject: Voyager's last photo
Date: 3 Nov 89 00:21:13 GMT
 
    I just got back from a lecture by Edward Stone, the Voyager
Project Scientist and Cal Tech prof.  Wonderful pictures, but I thought
I'd pass his news (first real confirmation I've heard, at least) that
the camera will be turned on sometime next February for a last
look-back picture of the solar system. 
 
    Mercury will be too close to the Sun to distinguish, and Pluto is
too faint/dark, but all the others should be imaged.  The inner planets
will be point sources, but the giants will be two or three pixels across. 

    Bill Wyatt, Smithsonian Astrophysical Observatory  (Cambridge, MA, USA)
    UUCP :  {husc6,cmcl2,mit-eddie}!harvard!cfa!wyatt
    ARPA:   [email protected]
    SPAN:   cfa::wyatt                 BITNET: wyatt@cfa

    
               <<< VISUAL::USERA:[NOTES$LIBRARY]IMAGING.NOTE;1 >>>
                          -< Forum on Imaging Issues >-
================================================================================
Note 519.0                  Planetary Images on CDROM                  7 replies
CASEE::MORRIS "Tom Morris"                          121 lines   7-SEP-1989 08:33
--------------------------------------------------------------------------------
Your very own CDROM with Voyager and Viking images from NASA and JPL for $9!

Sound too good to be true?  Read on...

SCOTTS VALLEY, Calif.--(BUSINESS WIRE)--Meridian Data Wednesday
announced that images collected by the Voyager and Viking planetary 
space missions have been stored and distributed on compact disc.

Such a disc is called a Compact Disc Read Only Memory (CD ROM), an 
extension of the same laser technology found in audio compact disc.

Several government agencies including NASA, the Jet Propulsion 
Laboratory (JPL), and the National Center for Supercomputing 
Applications (NCSA) contributed information for the CD ROM known as the 
GRIPS (Government Raster Image Processing Software and Data) disc.

Like the images beamed to earth from Voyager over the past week, 
the images available on the GRIPS disc reveal new planetary features. 

The initial GRIPS disc was developed on Meridian Data's own CD 
Professional, a recordable compact disc system, then sent to Philips 
and Du Pont Optical where 1,000 discs were replicated.

Distributing Voyager images on CD ROM provides some distinct 
advantages over computer online networks for scientists and 
researchers, according to Frederick Meyer, president of Meridian Data.

``These professionals can analyze and even manipulate the Voyager 
data on a standard PC instead of an expensive graphic workstation,'' 
explained Meyer.  ``Plus, the costs of connecting online disappear.''

The GRIPS disc adheres to the worldwide accepted ISO 9660 file 
format standard and is the first ISO 9660 CD ROM that can be accessed 
by either a PC or a Macintosh.  Toward this end, the GRIPS disc holds 
one set of data files that is shared across both computer platforms.

The GRIPS disc is available to the public while the supply lasts at 
a nominal fee ($9) to cover handling and shipping.

                                      ( 1 )


 -----       Voyager images available on compact            | 06-SEP-89
|C I S|      disc                                           | Business Wire
 -----       

For more information, contact Monica Meyer at Meridian Data, 
5615 Scotts Valley Drive, Scotts Valley, Calif. 95066. 

-0-

Note to Editors:  CD Publisher and the CD Professional are 
trademarks of Meridian Data Inc.


                                      ( 2 )

 -----       Voyager images available on compact     
|C I S|      disc                          
 -----  
             Source : Business Wire              Date : 06-SEP-89

     + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + 
     |  Please be advised that the information contained within this | 
     +  report is copyrighted material.  The following policies must + 
     |  be adhered to:                                               | 
     +                                                               + 
     |     -  No reformatting of the data segments                   | 
     +     -  No external distribution                               + 
     |     -  Internal use only in accordance with vendor agreements | 
     + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + 

    

Newsgroups: sci.space,sci.astro
Subject: Voyager 2 Update 12/6/89 (Forwarded)
Date: 6 Dec 89 17:15:14 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                       Voyager 2 Update
                       December 6, 1989
 
    Up to four more active ice volcanoes on Neptune's moon Triton were
discovered in snapshots taken by Voyager 2, which found the planet
itself is swept by 1,500 mph winds--the fastest yet seen in the solar
system. 
 
    Because the spacecraft photographed at least two and possibly five
of the geyser-like volcanoes erupting on only a portion of Triton,
"chances are that there are a dozen of these things going off
globally" at any time, said Torrence Johnson, a planetary scientist at
NASA's Jet Propulsion Laboratory. 
 
    Detection of more such volcanoes--which spew nitrogen ice and
gas--was announced Tuesday during a news conference at the American
Geophysical Union's fall meeting. 
 
    Voyager project scientists Edward Stone said Neptune's jet-stream
winds push frozen clouds of natural gas past the north edge of the
planet's Earth-size, hurricane-like Great Dark Spot at nearly 1,500 mph. 
 
    "These are the fastest we've observed," easily exceeding the
previous record winds of 1,100 mph in Saturn's jet stream, Stone said.
"These almost may be supersonic winds...a wind which is Mach 1." 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

Newsgroups: sci.space
Subject: Photographer of the decade.
Date: 29 Dec 89 17:33:26 GMT
Reply-To: [email protected] (David Anthony Kramer)
Organization: Princeton University, NJ
 
    The editors of the magazine 'American Photo' nominated Voyager 2
as the photographer of the decade, although they leave the final award
of the title to their readers. In the January/February 1990 issue they
define their criteria " the winner would have to have produced truly
astonishing pictures of sights we had never seen before - pictures
that had an impact both wide and deep." 

    "...it (Voyager) carried off its assignment with a kind of aplomb
and consistency the best pro shooters on earth could only dream of.
Voyagers pictures have gripped us enlightened us, showing how
beautiful our Universe must be - and how alone we are on our own 
tiny fragile planet...." 
 
    The article comparing the best photos of the decade leads off with
a two page false color picture of Saturn, taken by Voyager 2. 
           
    David Kramer
    Department of Electrical Engineering
    Princeton University
    Princeton, NJ 08544
 
    Internet,Bitnet: [email protected]
 
------------------------------------------------------------------------
Life can be modelled as a hidden Markov process with infinite states and
no a-priori knowlege of the probabability density functions.
------------------------------------------------------------------------

    Sorry, but isn't .148 a bit ridiculous?  I mean, would they think of
    nominating the Nikkormat Superflex 1002A (or whatever) as Photographer
    of the Anything?  Voyager is a tool used (among other things) to take
    photographs (I guess the in word is "images").  If anyone, the P of
    they D should be the Voyager Imaging Team.
    
    Burns
    

RE    <<< Note 532.149 by DECWIN::FISHER "Burns Fisher 381-1466, ZKO3-4/W23" >>>

  I agree 100% that the Voyager Imaging Team, and perhaps other folks
at JPL should get the award rather than the space probe. However, it is
probably the nature of the unmaned space program that the hardware and
not the people will get cited since no human was flying along.

  Even on maned flights the astronauts get a lot more than their share
of the credit. You didn't see many members of the booster crew on the
cover of life mag back in the early 1960's.

  I think this is just one of those realities of the space program that
we will have to live with.

  George

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 01/16/90
Date: 16 Jan 90 18:20:33 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      Voyager Mission Status Report
                           January 16, 1990
 
                             Voyager 1
 
    The spacecraft collected routine cruise science data throughout
this period.  A TLC test was performed on 1/1 and the X-band TWT was
switched to the high-power mode on 1/2.  A high-rate UVS observation
of omicron Andromedae on 1/3 and playback of Uranus photometric images
on 1/4-5 were lost due to the continuing non-availability of DSS 63
(failed elevation bearing). 
 
    On 1/2, the Bay 1 Heater was turned off and the X-Band TWT
commanded to the high power mode in preparation for Playback #6. 
 
    Activities for this period included the collection on low-rate UVS
data from the source omicron Andromedae, and low-rate F&P&W data
throughout the week. 
 
    A PRA POR occurred on 1/4.  The FDS algorithm successfully
restored the PRA to its nominal configuration.  This is the 35th POR
to occur since launch.  The most recent previous occurrence was on
8/7/89. 
 
    A total of 62:45 of tracking time (exclusive of overlaps) was
obtained.  Of this, none was large-aperture coverage.  While no
significant real-time telemetry outages were experienced, minor losses
amounted to 1:11 - 1.9% of the total scheduled support time. 
 
                             Voyager 2
 
    Routine cruise science data were collected throughout this period,
although substantial amounts were lost or severely degraded due to the
spacecraft's passage through superior conjunction.  The minimum
Sun-Earth-Probe angle (0.75 degrees) was attained on 1/2. 
 
    The collection of low-rate F&P&W data continued throughout this
reporting period and two frames of PWS were recorded, one each on
12/21 and 12/27, for later playback.  In addition, the scan-platform
was slewed to the target plate on 12/15 and the UVS read-out mode was
inhibited through 12/21.  On 12/21 the read-out mode was enabled for a
successful readout.  Shortly thereafter, the read-out was inhibited
again through 12/27 at which time the read-out was enabled for a
second successful read-out. 
 
    The Scan Platform was pointed to a UVS dark sky position.  Data
were of poor quality from 1/1 through 1/3.  This was not unexpected,
due to the low SEP angle of less than 2 degrees. There was a PRA POR
on 1/4. 
 
    A total of 75:45 of tracking time (exclusive of overlaps) was
obtained.  Of this, 4:20 was large-aperture coverage. 
  
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

So what is a PRA POR?  I presume PRA is one of the instruments, and POR is some
sort of error?

Burns

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 01/26/90
Date: 26 Jan 90 22:54:15 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                    Voyager Mission Status Report
                          January 26, 1990
 
                              Voyager 1
 
    The spacecraft continue to collect routine cruise science data
throughout this period.  The A001 sequence began execution nominally
on January 15 and one frame of high-rate PWS data was recorded. 
 
    Real-time command traffic was limited to January 17 and entailed
transmission of a dummy CC and enablement of the day 024 Cruise Maneuver.
 
    On January 11 and 12, Playback #8, containing Neptune Photometry
images 15 through 36, Magnetometer Autocal Data, and PWS data, was
executed. The data were not received because there was no DSN 70-meter
support available. 
 
    On January 17, the IRIS Flash Off Heater and Replacement Heater were
turned off because no further activity is planned for the IRIS instrument.
 
    Also on January 17, the AACS A and B Gyros were turned on, the
APPW Patch was delinked and a CCSTIM test was executed by the
spacecraft.  None of these activities was observed due to loss of
telemetry at DSS-15.  The station was experiencing heavy snowfall 
and, consequently, high System Noise Temperatures (SNT). 
 
    Spacecraft performance for all the sequenced activity during this
report period has been nominal. 
 
                              Voyager 2
 
    The spacecraft continue to collect routine cruise science data
throughout this period. High-rate UVS observations of HR 1679 were
performed on January 13 and 15. Only short periods of coverage could
be provided for these observations due to severe contentions with
other users for 70-meter support. 
 
    On January 15, a CCS A memory checksum and memory read-out
sequence was executed as a precursor to the scheduled CCS A memory
refresh. Real-time commands were then transmitted to perform the
memory refresh and downlink the post refresh checksums and memory
read-out.  However, due to a Galileo spacecraft emergency, our
scheduled DSS-43 pass was pre-empted and there was no station
available for the downlink of the CCS A refresh telemetry.  When 
a DSN pass was available on January 16, the spacecraft state was 
nominal for a successful completion of the refresh sequence. 
 
    On January 17, the X-band TWT was commanded to the high-power mode
and the Bay 1 heater was turned off.  Also on January 17, Playback #1,
containing the B001 Torque Margin Test, PWS data and Neptune
Photometry Images 1 through 24, was performed.  Only the last three
hours of the seven-hour fifty-minute playback was received due to the
lack of sufficient DSN 70-meter support. 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

    For UK interest, HORIZON on Monday 29th and Monday 5th are showing
    Voyagers mission thru the solar system.
    
    Chris

Newsgroups: sci.space
Subject: List of VOYAGER Acronymns
Date: 31 Jan 90 08:15:12 GMT
Reply-To: stan@hanauma (Stan Ruppert)
Organization: Stanford University, Dept. of Geophysics
 
    The following list of acronymns is from: 
 
      The Voyager Neptune Travel Guide by

         Voyager Mission Planning Office Staff
         Charles Kohlhase - Editor
         NASA-JPL-CIT
 
      June 1, 1989
      JPL Publication 89-24
 
    This is a fantastic publication which covers planning for the
Voyager Neptune Encounter in addition to being a great treatise on
mission personnel, spacecraft engineering, and science experiments.
The Guide also covers what science is planned during the Voyager
Interstellar Cruise portion of the mission. 

    Also discussed are the basics of how NASA communicates with far
ranging spacecraft, how flight trajectories are planned to use various
planets to 'sling-shot' the spacecraft along their way, and how the
Voyager team dealt with the various hardware problems that came up on
the spacecraft during the mission. 
-----------------------------------------------------------------------------
For a more detailed definition of terms included in the list of acronymns
below please refer to the Voyager Neptune Travel Guide.
-----------------------------------------------------------------------------

A         Voyager 1 reference
AACS      Attitude and Articulation Control Subsystem
AAI       All Axes Inertial
AD        anno Domini
AIAA      American Institute of Aeronautics and Astronautics
AM        Amplitude Modulation
ASFULL    PRA investigation of Neptune's magnetosphere
AU        Astronomical Unit (approx. 150 million km)
Az        Azimuth
B         Voyager 2 reference
BML       Backup Mission Load
bps       bits per second
C/A       Closest Approach
C^3       Command, Communications, and Control
cc        cubic centimeter
CCS       Computer Command Subsystem
CCSL      Computer Command Subsystem Load
CDSCC     Canberra Deep Space Communications Complex (Australia)
CDT       Capability Demonstration Test
CDU       Command Detector Unit
cm        centimeter
CM        Command Moratorium
CMC       Complex Monitor Control
CR        Cosmic Rays
CRS       Cosmic Ray SUbsystem
CRSMVR    Cruise Manuever
CSIRO     Commonwealth Scientific and Industrial Research Organization
            (Australia)
CST       Canopus Star Tracker
d         day
DACS      Data Capture and Staging
deg       degree
DRS       Data Records Subsystem
DSCC      Deep Space Communications Complex
DSN       Deep Space Network (NASA)
DSS       Data Storage Subsystem, or Deep Space Station
DTR       Digital Tape Recorder
EDR       experiment Data Record
El        Elevation
ENC-REL   Encounter-Relative (time)
ERT       Earth-Received Time (occasionally, encounter relative time)
EUV       Extreme Ultraviolet
EUVE      Extreme Ultraviolet Explorer
F&P       Fields and Particles
FDS       Flight Data Subsystem
FE        Far Encounter Phase
FM        Frequency Modulation
FOO       FLight Operations Office
FOV       Field of View
FPA       Fault Protection Algorithm
FSO       Flight Science Office
FSTEP     LECP observation to detect rapid variations in Neptune's 
             radiation field
ft        foot
FUV       Far Ultraviolet
GCF       Ground COmmunications Facility
GDS       Ground Data System
GDSCC     Goldstone Deep Space Communicaions COmplex (California)
Ghz       GigaHertz (one billion cycles per second)
gm        gram
GMT       Greenwich Mean Time
GS&E      General Science and Engineering
GSFC      Goddard Space Flight Center
H         Hydrogen
h or hr   hour
He        Helium
HGA       High Gain Antenna
ICE       International Comet Explorer
IDC       Image data compression
IMC       Image MOtion Compensation
INTA      National Institute for Aerospace Techniques (Spain)
IPM       Interplanetary Medium
IR        Infrared
IRIS      Infrared Interferometer Spectrometer and Radiometer Subsystem
ISAS      Institute of Astronautical Science (Japan)
ISM       Interstellar Medium
ISS       Imaging Science Subsystem
IUE       International Ultraviolet Explorer
JPL       Jet Propulsion Laboratory
kbps      kilo(1000) bits per second
kg        kilogram
km        kilometer
LAN       Local Area Network
lb        pound
LECP      Low Energy Charged Particles Subsystem
LEMPA     Low Energy Magnetospheric Particle Analyzer (in LECP)
LEPT      Low Energy Particle Telescope (LECP)
LETS      Low Energy Telescope System (CRS)
LEU       Late Ephemeris Update
LMC       Link Monitor Control
LSU       Late Stored Update
m         meter (also minute)
MAG       Magnetometer Subsystem
MAGROLL   Spacecraft roll maneuver
MCCC      Mission Control and Computing Center
MCT       Mission Control Team
MHz       MegaHertz (one million cycles per second)
mi        mile
MIMC      Maneuverless Image Motion Compensation
MIPS      Multimission Image Processing Subsystem
MJS77     Mariner Jupiter/Saturn 1977
mm        millimeter
mph       miles per hour
MPO       Mission Planning Office
NA        Narrow Angle (imaging)
NASA      National Aeronautics and Space Administration
NASCOM    NASA Communications Network
NAV       Navigation Team
NE        Near Encounter Phase
NEC       Near Encounter Contingency
NET       Near Encounter Test
NIMC      Nodding Image Motion Compensation
NMB       Neptune Movable Block
NRAO      National Radio Astronomy Observatory
OAO       Orbiting Astronomical Observatory
OB        Observatory Phase
OCC       Occultation
OPNAV     Optical Navigation
ORT       Operational Readiness Test (radio science)
OWLT      One-Way LIght Time
PDT       Pacific Daylight TIme
PE        Post-Encounter PHase
PEO       Public Education Office (JPL)
PIO       Public Information Office (JPL)
PLS       Plasma Subsystem
POT       Potentiometer
PPS       Photopolarimeter Subsystem
PPVPHOT   Photometeric observation of Neptune's atmosphere
PRA       Planetary Radio Astronomy Subsystem
PWS       Plasma Wave Subsystem
R-axis    The R-S-T axes refer to an orthogonal targeting coordinate system,
             where S points in the same direction as the target-relative 
             approach hyperbolic excess velocity, T is parallel to the ecliptic
             plane, and R is 'down'.
rads      100 ergs per gram of irradiated material
RFA       Request for Action
RFS       Radio Frequency Subsystem
RODAN     Radio Occultaion Data Analysis
RPDISK    IRIS observation of Neptune's disk
rpm       revolutions per minute
RPOCCPT   IRIS observation of radio science occultation point in 
             Neptune's atmosphere.
RS        Reed-Solomon; Radio Science
RSS       Radio Science SUbsystem
RTG       Radioisotope Thermoelectric Generator
RTMAPIN   IRIS map of lit side of Triton
RTMAPOUT  IRIS map of dark side of Triton
S/C 31    Voyager 1 reference
S/C 32    Voyager 2 reference
SC        Scan Converter
SCET      Spacecraft Event Time
SCT       Spacecraft Team (sometimes Spacecraft TIme)
SDT       Science Data Team
sec, s    second
SEDR      Supplementary Experiment Data Record
SEQ       Sequence Team
SIS       Science Investigation Support Team
SNR       Signal-to-Noise ratio
SOC       Science OPerations Coordinator
SPC       Signal Processing Center
SSG       Science Steering Group
SWG       Science Working Group
T-axis    refer to R-axis
TBD       To Be Determined
TC        Thermal Cycle
TCM       Trajectory Correction Maneuver
TET       Electron Telescope (CRS)
TMB       Triton Movable Block
TMT       Torque Margin Test
TTS       Test and Telemetry Subsystem
TV        Television
U/L       Uplink
UPCORONA  UVS observations of Nepturne's corona
UPDKPOL   UVS ovservations of Neptunes' dark pole
USO       Ultra Stable Oscillator
UTCDRFT   UVS ovservation of co-rotation plasma near Triton
UTGLOW    UVS observations of airglow emissions from Triton's atmosphere
UTHOCC    UVS ovservation of Triton's outer atmosphere during occultaion
UTPLASMA  UVS ovservation of co-rotation plasma near Triton
UV        Ultraviolet
UVS       Ultraviolet Spectrometer Subsystem
VCR       Video Cassette Recorder
VGR       Voyager
VIM       Voyager Interstellar Mission
VISA      Voyager IMaging Support Activity
VLA       Very Large Array
VMB       Vernier Movable BLock
VNBEST    Highest resolution picture of Nereid
VNESSA    Voyager Neptune Encounter Science Support ACtivity
VRARCMOV1 Narow-angle images of possible ring arcs
VRDETECT  Narrow-angle mosaics to search for possible ring arcs
VRHIPHAS  Images of possible ring arcs as sunlight is scattered through them
VRMOS1,2  Narrow-angle images to observe possible ring arcs
               or shepherding satellites
VRRET1    Retargettable images of a possible newly discovered
               ring-arc (acronym subsequently changed to VRRETINX)
VRRETINX  See VRRET1;x=0,1,2,3, for specific application of VRRET1
VRXING2   Imaging ovservations during outbound ring plane crossing
VTCOLOR   Highest resolution color images of Triton
VTERM     Highest resolution images of Triton
VTLON     Periodic Imaging of Triton as it orbits Neptune
VTMAP     Images to map Triton's surface
WA        Wide Angle (imaging)
WPOLE     PWS observations of plasma wave signals near Neptune's north pole
WS        Work Station
WSFULL    PWS observation of plasma wave signals in Neptune's 
               inner magnetosphere
WSHORT05  5-second PWS observations of plasma wave signals in
               Neptune's inner magnetosphere
WSHORT10 10-second PWS observations of plasma wave signals in
               Neptune's inner magnetosphere
WWII     World War II
XROCC    Radio science observations of ring during occultaion
XPOCC    Radio science observations of Neptune's atmosphere during occultaions
XSGRAV   Radio Science observations of gravity fields of Neptune and Triton
XTOCC    Radio science observations of Triton's atmossphere during occultation
------------------------------------------------------------------------------ 
=============================================================================
Stan Ruppert
Dept of Geophysics
Stanford University, CA 94305
Email Addr: (Internet) [email protected]
=============================================================================

Back a few replies, one chap talked about not being able to get some
    data due to contention fo the 70 metre station. Does the 70 metre
    here refer to wavelength, or does it refer to the physical diameter
    of the recieving antenae.
    Blissfully ignorant? R. Tomkins

    Re:.156
    	70 Meters refers to the size of the antenna.
    
    				Drew
    

  I asked this in the astronomy conference, but no one answered me.
Why does Voyager 1 have "Neptune Photometry images" to be played back?
Does that imply that Voyager 1 studied Neptune in some fassion? I
didn't think Voyager 1 went anywhere near Neptune.

  George

Just speculation:  It might have been studying some star occultation by Neptune
from a significant distance.

Anyone know?

Burns

From: [email protected] (Peter Scott)
Newsgroups: sci.space
Subject: Voyager Update
Date: 9 Feb 90 23:56:18 GMT
Organization: The Internet
 
    Extracted from NASA' _Voyager Bulletin_, Mission Status Report
#98, January 29, 1990: 
 
    On February 14, Voyager 1 will take advantage of an historic and
unique opportunity to image most of the solar system's planets, taking
a final look back at where the Voyagers have been and showing Earth
among its fellow planets. 
 
    Earth, Venus, Jupiter, Saturn, Uranus and Neptune will be targeted
in a sequence of wide- and narrow-angle images.  Mars may be visible,
but it will be a slim crescent close to the Sun, while Mercury will be
masked in the Sun's glare.  Pluto is too far away and too small to be
imaged.  From Voyager 1's viewpoint, the planets will appear to be
clustered along the constellation Eridanus (The River). 
 
    Voyager 1 will be approximately 40 [AU] from Earth and 32 degrees
above the ecliptic plane at an ecliptic longitude of 242 degrees.  A
series of about 64 images will be taken, beginning with Neptune.  The
wide-angle frames will be taken through clear filters, while the
narrow-angle frames, each centered on a planet, will be shuttered
through blue, violet, and green filters.  The spacecraft will roll to
take images of regions that would otherwise be obscured by the
spacecraft's high-gain antenna.  Images of the inner planets will be
mosaicked around the Sun to avoid direct sunlight. The final
wide-angle frame will be centered on the Sun. 
 
    Due to tracking schedules, the images will be recorded on board
the spacecraft and returned to Earth in late March.  Several weeks
will then be needed to process the images to reveal as much detail as
possible.  Most of the planets will be smaller than a pixel in size;
however, Jupiter may be as large as four pixels.  (Voyager's imaging
frame is 800-by-800 pixels.) 
 
    Due to the scale, it is unlikely that the entire set of images can
be mosaicked to produce for publication a single photograph showing
all the planets stretched from Jupiter to Neptune.  A display of this
mosaic would requirea wall 100 to 150 feet long, depending on the
chosen size of the individual prints.  Imaging team members hope to
release at least the central frames showing Earth, Venus, and perhaps
Mars together. 
 
    Voyager 1 was chosen over Voyager 2 for this task due to
operational considerations.  Another factor is the fact that Jupiter
would be too close to the Sun to be visible from Voyager 2's point of
view this spring. 
 
    Although the ultraviolet spectrometer is still on, the sunlight
will be too bright to allow observations during this imaging sequence.
The infrared spectrometer and photopolarimeter instruments will not
be on.  The only potential damage from pointing these optical
instruments too close to the Sun is that the shutter blades of the
wide-angle camera might warp due to the increased heat of the sunlight
focused on the blades. 
  
    UPDATE
 
    Contact with Voyager 1 has been normal since a partial loss of
contact last fall.  On October 23, Voyager 1 stopped sending its
telemetry signal, by which science and engineering data are
transmitted.  The carrier signal, a single frequency used to track the
spacecraft's location, continued. Commands were sent to reset the
spacecraft's telemetry modulation unit. Controllers waited 11 hours
for the signal to reach the spacecraft and a return signal to reach
Earth before they knew that full contact had been restored.  Flight
controllers had no explanation for the one-time event, but there was
smoe conjecture that it was related to high solar activity. Several
other spacecraft also experienced computer problems during last fall's
spate of huge solar flares.  The high-speed particles ejected by solar
flares can cause computer bits to "flip" from the desired position. 
  
    NEPTUNE RESULTS
 
    The Voyager science teams have submitted their "30-day reports" on
the Neptune encounter, as required in their contracts with NASA, and
these reports have been published in the December 15, 1989 issue of
_Science_ magazine.  As the papers were being written, data analysis
continued, bringing new information to light.  Changes from what has
been previously reported in the _Bulletin_ are summarized below. 
 
    Neptune's rotation rate is now cited as 16 hours 7 minutes +/- 1
minute, based on data from the planetary radio astronomy instrument. 
 
    Winds near the Great Dark Spot are now believed to be a
rip-roaring 560 [m/s] (1230 [mph]), the strongest winds yet measured
in the solar system. (Voyager measured winds on Saturn up to 500 [m/s]
or 1100 [mph].) 
 
    The cloud streaks seen near latitudes of 27N and 71S are estimated
to be about 100 km (60 mi) and 50 km (30 mi) respectively, above the
cloud banks on which their shadows were seen. 
 
    Temperatures at high altitudes in Neptune's stratosphere have been
measured to be about 750K. 
 
    The tilt of Neptune's magnetic field is now given as 47 degrees
from the rotational axis, while the offset of the magnetic pole from
the center of the planet is 0.55 radius.  The strength of the surface
magnetic field varies from more than 1 to less than 0.1 gauss. 
 
    As Voyager 2 passed through the ring plane, the maximum impact
rate from ring particles was measured at 250 hits per second. 
 
    Triton's surface temperature has been revised to 38K (about
-391F), while the surface pressure is now believed to be about 14
microbars.  Methane and nitrogen form a thin veneer on the moon's
surface, while the underlying topographic features are suspected to be
formed of water ice.  Methane and nitrogen ices are too weak to
support their own mass for very long in such formations. 
 
    At least six small, previously unknown satellites, ranging in
diameter from 54 to 400 km, have been identified in Voyager images. 
Names will be assigned by the nomenclature committee of the [IAU]. 
 
    Researchers will continue to publish science results of the
Voyager mission in professional journals such as _Geophysical Research
Letters_ [gotta be an oxymoron there - PJS] and the _Journal of
Geophysical Research_ for many years to come.  The Voyager mission has
provided a unique data set for comparative planetology; four planetary
systems studied by the same instruments.  
 
    Peter Scott ([email protected])

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 02/23/90
Date: 24 Feb 90 04:44:01 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
		    Voyager Mission Status Report
			  February 23, 1990
 
			      Voyager 1
 
     On February 9, AACS Gyros A and B were turned on and initialized.
Spacecraft performance for the activity was nominal. The following
activities were supported on February 12: an ASCAL, recording of one
frame of high-rate PWS data, and a TLC test. High-rate UVS
observations were conducted on BW Vulpeculae (February 13) and lambda
Eridani (February 14). Most of the data were not observed in real-time
due to no large-aperture coverage being available. 
 
     On February 13, the ISS narrow and wide angle cameras were turned
on and the VPLANETS sequence was executed. It was necessary for the
Voyager 1 spacecraft to roll to a new lock star (Peacock) in order to
acquire the Jupiter, Earth, and Venus images. Following the sequence,
the wide and narrow angle cameras were turned off.  Only the camera
turn on and a -318.2x roll turn to Peacock as the roll axis celestial
reference were observed in real time due to a lack of Deep Space
Network (DSN) station availability.  The VPLANETS sequence was
programmed to record images of Neptune, Uranus, Saturn, Mars, Jupiter,
Earth, Venus, and various star fields.  A total of 21 narrow angle and
39 wide angle images were recorded.  The AACS scan platform pointing
was 1x from the Sun in the final images taken of Venus.  Playback of
these images is scheduled for 3/16, 3/20, 3/23, and 3/27. 
 
     Following the sequence execution and return to CR-5 data mode,
all observable spacecraft parameters appeared to be nominal.  This was
the last planned use of the AACS DSSCAN patch and ISS cameras. 
 
     On February 15, the X-Band TWT was commanded to the low power
mode and the Bay 1 heater was turned on. 
  
			      Voyager 2
 
     Voyager 2 continues to collect routine cruise science data. On
February 12, one frame of high-rate PWS data was recorded and a
high-rate UVS observation was conducted on Feige 7. Neither of these
activities were observed in real-time due to lack of DSN station support. 
 
     On February 14, an RFSCMD (threshold) test was executed by the
DSN station in Goldstone, California. Due to procedural errors during
the test, the test was not completely successful. Procedural changes
will be made before the next attempt of a RFSCMD test.  This was the
first time that this particular test sequence had been attempted. 
 
     Spacecraft performance for all the sequenced activity during this
report period has been nominal. 
  
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 03/02/90
Date: 3 Mar 90 03:24:38 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                     Voyager Mission Status Report
                           March 2, 1990
 
                              Voyager 1
 
     Voyager 1 continues to collect routine cruise science data.  On
February 17, the Magnetometer measured an increase in the magnetic
field by a factor of 2 or more.  The Plasma, CRS, and LECP instruments
are not recording any corresponding change. 
 
     On February 19, an ultraviolet spectrum (UVS) observation was
executed from the source SV Centauri (aka HD 102552). Only the first
one and one-half hours of the five hour data mode period was received
due to the lack of Deep Space Network (DSN) 70-meter support. 
 
     On February 21, the  Attitude and Articulation Control Subsystem
(AACS) A and B gyros were reinitialized. 
 
     Photopolarimter Radiometer (PRA) data is processed and analyzed
data daily for the purpose of observing and logging radio events of
interest to the PRA team. 
 
                              Voyager 2
 
     AACS Scan Platform Slews on February 19 and February 22 were
executed without downlink visibility due to lack of DSN support. 
 
     A UVS observation was executed on February 21. UVS low-rate data
were taken on sources Feige 7 and EG165, a white dwarf. High-rate data
were taken on EG165 on February 21. Only three and one-half hours of
the twelve hour data mode was observed due to lack of sufficient DSN
support. 
 
     Spacecraft performance for all the sequenced activity during this
report period has been nominal. 
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 03/09/90
Date: 9 Mar 90 18:39:44 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                     Voyager Mission Status Report
                            March 9, 1990
 
                              Voyager 1
 
     Voyager 1 continues to collect routine cruise science data.  One
frame of high-rate plasma wave data (PWS) was recorded on February 26.
High-rate ultraviolet spectrum (UVS) observations were conducted on MU
Centauri (February 27) and HD 206165 (March 1).  All of the former
observations was lost due to lack of Deep Space Network (DSN) coverage. 
 
     On February 28, a negative 41.8x roll turn was executed by the
spacecraft and Rigil Kentaurus was re-acquired as the roll axis
celestial reference.  Following the maneuver, the Attitude and
Articulation Control Subsystem (AACS) A and B gyros were turned off.
AACS Canopus tracker and Sun Sensor Gate parameters were also updated
and verified by AACS Memory Read Out following the maneuver. 
 
     The shutter blades of the wide-angle camera are suspected to be
warped when the camera was pointed towards the Sun on February 14 to
take the "family portrait" pictures.  All of Voyager 1's cameras are
turned off and there are no further plans to use them again.  The first
set of pictures will be transmitted back to Earth on March 16 of the
planets Neptune and Uranus. 
 
     March 5 marked the 11th anniversay of Voyager 1's Jupiter encounter.
 
                              Voyager 2
 
     Voyager 2 also continues to collect routine cruise science data.
One frame of high-rate PWS data was recorded  on February 26. UVS
low-rate data were taken on sources EG165, a white dwarf star, and
PKS2155-304.  High-rate data were taken on both sources on February
26, but station coverage was unavailable. 
 
     The MAG, PLS, and LECP instruments all responded to the
calibration commands as expected on February 28. 
  
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 03/23/90
Date: 23 Mar 90 17:26:41 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                              Voyager
                       Mission Status Report
                          March 23, 1990
 
                              Voyager 1
 
     Voyager 1 continues to collect routine cruise science data. 
High-rate Ultraviolet Spectrometer Subsystem (UVS) observations were
conducted on HD 206165 (March 2) and Markarian 509 (March 6 and March
13).  One frame of high-rate Plasma Wave Subsystem (PWS) data was
recorded on March 5 and March 12. 
 
     An AGC/Command threshold test was executed on March 7.  This is
the first time that this particular test was performed on Voyager 1. 
A number of verification alarms were experienced during the uplink of
the AGC/Command Threshold test, but the alarms did not appear to have
any adverse impact on the test, and the test was completed successfully. 
 
     The processing and analysis of Planetary Radio Astronomy
Subsystem (PRA) Experiment Data Record (EDR) data continues daily, for
the purpose of observing and logging radio events of interest to the
PRA team. 
 
     On March 13, a Magnetometer (MAG) sequence was executed by the
spacecraft.  No problems were encountered and the spacecraft
performance was nominal. The instruments responded satisfactorily. 
 
     Images from the "family portrait" have been transmitted back to
Earth.  Uranus and Neptune images were successfully sent back on March
16, and Saturn images on March 20.  The remainder of the images are
scheduled for transmission from the spacecraft's tape recorders for
tonight (Mars) and for March 27 (Jupiter, Earth and Venus). 
 
     Spacecraft performance for all the sequenced activity has been nominal.
  
                              Voyager 2
 
     Voyager 2 continues to collect routine cruise science data.  One
frame of high-rate PWS data was recorded on March 5 and March 12.  The
AB gyro pair was turned on on March 5.  Thermal events (AB gyros on)
induced a command moratorium that resulted in approximately two days
of this period being unavailable for acquisition of ranging or
coherent Doppler data. 
 
     High-rate UVS observations were conducted on HD 212571 (March 5)
and NGC 7027 (March 7, 12, 13, and 14).  Most of this data was lost
due to the limited Deep Space Network (DSN) coverage.  An Attitude and
Articulation Control Subsystem (AACS) test and Computer Command
Subsystem (CCS) timing offset determination were performed on March 7.
 
     A Cruise Maneuver (CSRMVR) was performed on March 14 and a PLSCAL
on March 15.  Commands to update the AACS yaw and roll axes were also
transmitted in preparation for the mini-CRSMVR executed on March 14.
The update was verified by an AACS Memory Read Out. 
 
     Spacecraft performance for all the sequenced activity has been nominal.
  
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 05/02/90
Date: 3 May 90 00:48:27 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                    Voyager Mission Status Report
                             May 2, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data.  On April 16 one frame of high-rate Plasma Wave (PWS)
data was recorded. 
 
     On April 17, Attitude and Articulation Control Subsystem (AACS),
Computer Command Subsystem (CCS), and Flight Data Subsystem (FDS)
memory readouts and a playback of PWS and Imaging Science (ISS) data
were performed. (The ISS data consisted of the "family portrait"
images lost due to rain during the March 23 playback.)  Due to a maser
failure at the 70 meter antenna in Spain (DSS-63), the AACS and CCS
memory read-outs were not useable, and because of the low signal level
Playback #1 was lost completely.  The 34 meter antenna in Spain
(DSS-65), which was to be arrayed with DSS-63 for the playback, was
able to recover most of the FDS memory readout. A mini-sequence to
recover the lost playback data was generated and was uplinked on April
27. The mini-sequence was executed on May 1 and the remaining "family
portrait" images were transmitted back successfully. 
 
     High-rate Ultraviolet Spectrometer (UVS) data was also taken on
HD120324 on April 19. 
 
                               Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  One frame of high-rate PWS data was recorded on April
16 and a high-rate UVS observation of HD 164284 was conducted on April
17.  Due to the lack of Deep Space Network (DSN) 70 meter station
coverage, only two and one-half hours of the twelve hour observation
were received. 
 
     Spacecraft performance for all of the sequenced activity has been
nominal. 
  
                         CONSUMABLE STATUS
 
     P R O P E L L A N T   S T A T U S                 P O W E R

                 Consumption
                  One Week    Propellant Remaining    Output Margin
    Spacecraft      (Gm)             (Kg)              Watts  Watts
 
     Voyager 1       6         36.5 + 2.0              370   60
     Voyager 2       5         39.6 + 2.0              374   66
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

What is the unit "Gm" for propellent used in a week?  Maybe a reversed
Milligrams?  (Seems pretty small).

Also, can't you imagine some intelligent being on Voyager looking at the
commands being sent and saying, "For heavens sake...this is the 5th time they've
asked me to downlink that stupid picture.  What's the matter with them!"

Burns

    Re:.166
    	"Gm" is a non-standard abbreviation for "gram"
    
    				Drew
    

Re: .167

  "Gm" is actually Giga-metres - i.e. a million kilometres.

  Of course, the distance the Voyager spacecraft have travelled is a
  substantion number of Gm.  :-)

jb

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 05/04/90
Date: 4 May 90 15:11:38 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      Voyager Mission Status Report
                             May 4, 1990
 
                              Voyager 1
 
     Voyager 1 continues to collect routine cruise science data.  One
frame of high-rate Plasma Wave (PWS) data was recorded on April 24. 
High-rate Ultraviolet Spectrometer (UVS) observations of HD 120324 and
HD 217675 were conducted on April 20 and April 23, respectively.  All
of the latter observation was lost due to lack of Deep Space Network
(DSN) coverage.  A Computer Command Subsystem (CCS) timing offset
determination performed on April 25 indicated that an unexpected
offset of approximately 120 milliseconds existed between the Flight
Data Subsystem (FDS) and both CCS processors. This situation is under
investigation. 
 
     Also on April 23 the Attitude and Articulation Control Subsystem
(AACS) B and C gyros were turned on in preparation for the ASCAL
executed on April 27 and the spacecraft roll manuever (MAGROL)
sequenced for May 1.  No problems were experienced and spacecraft
performance was nominal. 
 
     On April 24 it was discovered that no spacecraft engineering
telemetry had been processed during the entire preceding pass of the
70 meter antenna at Goldstone (DSS-15).  This anomaly was not noticed
by "off-shift" monitoring personnel and no project personnel were
notified.  Following analysis, the Test and Telemetry Subsystem (TTS)
was found to be configured to process wide band instead of high speed
data.  This configuration change should have been made prior to the
DSS 15 pass. 
  
                              Voyager 2
 
     Voyager 2 also continues to collect routine cruise science data. 
One frame of high-rate PWS data was recorded on April 24. High-rate
UVS observations of iota Herculis and HD 193322 were conducted on
April 20 and April 25, respectively.  The 2 hours and 50 minutes of
the UVS high-rate data taken on HR6558 was badly degraded due to rain
and is probably unusable.  The data taken on HD 193322 on April 25 was
of good quality. 
 
     On April 25 AACS, CCS, and FDS memory read-outs were performed.
Spacecraft and DSN performance appeared nominal for the activity. 
However, excessive lines were missed by TTS LP17 during the AACS
read-out.  The CCS and FDS readouts were very clean with very few
outages. 
 
     Also on April 25, a sequence to calibrate the Plasma Subsystem
(PLS) and Magnetometer Subsystem (MAG) was executed.  The calibrations
went nominally and the instrument data looked good.  However, a
problem was observed in which two science channels were not being
processed and output to the General Science character printer. 
Subsequent analysis revealed that the problem was present when TTS
software version 9.0 was on line and not present with version 8.8. 
 
 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: Voyager Confirms Relativity
Date: 4 May 90 15:08:33 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    From Sky & Telecope, June 1990
 
    VOYAGER CONFIRMS RELATIVITY
 
    When photons escape the gravity of a massive object, they lose
energy and their wavelengths increase correspondingly.  Such a
gravitational redshift, amounting to just one part in a billion or 
so, was measured by Timothy P. Krisher and colleagues at NASA's Jet
Propulsion Laboratory.  They used tracking data from Voyager 1's 
flyby of Saturn in November of 1980. 
 
    Their results, reported in the March 19 Physical Review Letters,
confirm the predictions made by the general theory of relativity to an
accuracy of 1 percent.  Krisher and co-workers are now refining their
observations using Voyager 2 data from Uranus and Neptune. 
 
 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: Voyager Update - 05/08/90
Date: 8 May 90 15:46:24 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                     Voyager Mission Status Report
                             May 8, 1990
 
                              Voyager 1
 
     Voyager 1 continues to collect routine cruise science data.  Two
high-rate Ultraviolet Spectrometer (UVS) observations of HD 217675
were conducted on April 27. On May 2 one frame of high-rate Plasma
Wave (PWS) data was recorded. 
 
     On April 27 a real time command mini-sequence was transmitted. 
This sequence executed as scheduled on May 1, and provided the
successful playback and recovery of the remaining "family portrait"
imaging data, as well as three frames of PWS data.  Real-time
observation of the playback images indicated that four imaging frames
were fragmented as processed by the Multimission Image Processing
Subsystem (MIPS) however, three of the images appeared to have all of
the necessary data to build a complete frame.  MIPS indicated that
there were indeed internal problems during the real-time processing
and these images would be reprocessed as soon as possible. 
 
     A real-time command file to reset the Computer Command Subsystem
(CCS) status telemetry was also transmitted on May 1.  A CCS memory
read-out was performed and verified the reset of the CCS status
telemetry. 
 
     The time offset between the CCS and the Flight Data Subsystem
(FDS) reported previously was ascribed to an FDS Power On Reset (POR)
that occurred during a tracking gap.  Real-time commanding was
performed in an attempt to correct the offset.  On April 30, a CCS
timing offset determination was transmitted that confirmed the offset.
On May 1, a clock reset sequence was transmitted to correct the
offset, followed by another CCS timing offset determination (to verify
the correction).  Unfortunately, the clock reset sequence was not
properly integrated with other activities (the planned transmission
time was insufficienty delayed from a reset of the CCS integrated
telemetry status word) and the sequence was not acted upon by the CCS.
Another attempt at removing the offset is being planned, and a CCS
clock adjustment is now scheduled for May 16. 
 
     A spacecraft roll manuever (MAGROL) was also executed on May 1. 
This resulted in the successful execution of the ten revolution roll
turn maneuver and subsequent power down of the Attitude and
Articulation Control Subsystem (AACS) B and C gyros. 
 
                              Voyager 2
 
     Voyager 2 also continues to collect routine cruise science data.
High-rate UVS observations of HD 200120 were conducted on April 30 and
May 3. (Most of these observations were not acquired due to limited
Deep Space Network (DSN) station availability.)  One frame of
high-rate PWS data was recorded on May 1. 
 
     Memory compares of the AACS and CCS memory read-outs performed on
April 25 have been completed.  These compares indicate that memory
contents for the AACS and CCS are as expected. 
  
                      CONSUMMABLE STATUS
 
    P R O P E L L A N T    S T A T U S            P O W E R

               Consumption
        One Week    Propellant Remaining     Output     Margin
  Spacecraft (Gm)             (Kg)           Watts      Watts
   Voyager 1  42            36.5 + 2.0        370         59
   Voyager 2   6            39.6 + 2.0        374         66
 
 Ron Baalke                       |    [email protected] 
 Jet Propulsion Lab  M/S 301-355  |    [email protected] 
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

    
    When will the picture(s) be available ?
    
    Chris

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 05/16/90
Date: 16 May 90 15:32:10 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                  Voyager Mission Status Report
                         May 16, 1990
 
                           Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data. On May 4 a six hour Ultraviolet Spectrometer (UVS)
observation of HD 217675 was executed; there was no Deep Space Network
(DSN) 70 meter antenna support available therefore the downlink of
this observation was not received. On May 7 a frame of Plasma Wave
(PWS) data was recorded for future playback. 
 
     A Digital Tape Recorder (DTR) Tape Position (TAPPOS) slew was
executed in the low rate for the first time on May 8.  The tape
position arrived at was as expected however, a speed reduction of 2%
was observed from the nominal 7.2 kbps slew rate.  This is a known
idiosyncrasy of the DTR when operating without the 7.2 kbps reference
signal normally provided by the Flight Data Subsystem (FDS).  This
reference signal is not provided when the DTR is in the Slew mode or
when operating a non-record or playback data mode. 
 
     Also on May 8 Playback #2, containing spacecraft roll maneuver
(MAGROL) data, was executed using the Plasma Wave Subsystem Data
Playback (PWSPB) Block Routine (BR9).  This was the first execution of
this block and the spacecraft performance was nominal.  There was
however, a maximum of -0.5 db downlink degradation introduced into the
DSS 63/65 array (70 meter and 34 meter antennas in Spain arrayed
together) due to a problem with the DSS 63 sub-reflector being fixed
at the 35 degree position.  The data quality appeared to be acceptable
for the playback.  
 
                           Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  On May 7 and May 10 eleven hour UVS observations of
Markarian 509 were executed by the spacecraft; there was no 70 meter
DSN support available for either observation therefore downlink of
this data was not received.  On May 8 a frame of PWS data was recorded
for future playback. 
 
     A Plasma instrument calibration (PLSCAL) was executed by the
spacecraft on May 9.  Performance of the calibration was nominal and
no problems were experienced. 
 
     The memory compare process has been completed on data received
from the FDS memory read-out performed on April 25.  The compare
indicates that the FDS memory contents are as expected. 
 
     Spacecraft performance for all of the sequenced activity during
this report period has been nominal. 
  
                  CONSUMABLE STATUS AS OF 5/15/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
             Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
  Voyager 1    4              36.5 + 2.0          370         59
  Voyager 2    4              39.6 + 2.0          374         66
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

I'm confused about the "Propellant Status" that have been given in the past few
replies.  What does the first column mean?  By "Consumption" does it mean
distance traveled in a given week (based on the "Gm" explanation a few notes
back)?  And what about the second column "Propellant remaining"?  Since the
numbers haven't changed for a while I assume that the spacecrafts are not using
any, i.e. they're in "cruise mode" without the need to adjust their flight path.
How am I doing?  I think I understand the "power" columns, but you can explain
it if you feel like it.  Any data around just how far away these babies are from
Earth?  The Sun?  Alpha Centauri?  :-)

...Roger...

    Re. -1
    
    "Consumption" stands for propellant used per week, in grams (gm)
    "Propellant remaining" is in kilograms (Kg) - I believe the "+ 2.00"
    figure refers to a reserve amount.
    "Power" refers to the output of the plutonium-fueled generator.
    "Threshold" refers to the minimum amount of power needed for the
    Voyagers to maintain contact with the Earth.  (guess?)
    
    						--Eric--
    
    P.S.  Given the amount of propellant consumed (both on the spacecraft
    and on the booster) and the miles traveled, I wonder what the EPA
    mileage figures for the Voyagers would be?  ;^)

Depends if you include the fuel used in the booster or not :-)

Burns

From: [email protected] (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space
Subject: What Voyagers are up to.
Date: 18 May 90 11:50:00 GMT
Organization: The Internet
 
    Now that all the planets on the Voyagers' itinerary have been
passed, some of their instruments are essentially useless.  The
imaging and infrared spectroscopy gadgets have nothing close enough or
bright enough to look at anymore.  As a one-time stunt (I almost said
"one-shot," but then remembered it's a mosaic (-:), Voyager 1 snapped
the "family portrait" showing the bodies of the Solar System as little
dots.  Data are back on the ground, and we oughta see the result any
week now.  The final frame of the portrait showed the Sun, and in
taking it solar heat may have damaged the shutter of one camera
permanently.  That's okay-- Voyager 1 will never need that camera
again. (Barring flying saucer visits.)  If there is a scientific
purpose to the family portrait, I'm not aware of it.  But it's a nice
thing to have. 
 
    Other instruments aboard continue to gather interesting
information, which is what JPL means by "routine cruise science."  The
particles-and-fields stuff reports on the environment at the edge of
the solar system; examples include the Plasma Wave System, the
Magnetometer, and Low Energy Charged Particle instrument.  As the
plutonium in the generators decays and power runs low in the years to
come, instruments and their heaters will be shut off, starting with
the cameras.  But the Voyager gang hopes to hit the heliopause-- the
boundary between the solar wind and the interstellar wind-- in the
next decade or two.  So they'll need as many of the P&F experiments 
running as they can manage. 
 
    One special case is the Ultraviolet Spectrometer (UVS), which sits
on the scan platform with the cameras and the infrared spectrometer. 
Its primary purpose is for looking at ultraviolet emission and
absorption lines in the atmospheres of planets.  It is sensitive to
wavelengths in the "extreme ultraviolet," between 500 and 1700 angstroms. 
 
    Now, it happens that not much astronomy has been done in these
wavelengths. The galaxy has clouds of interstellar hydrogen.  A "Lyman
alpha" photon (912 angstroms, 13.6 electron volts) has enough energy
to ionize neutral hydrogen. Any photon of wavelength *shorter* than
this runs the risk of bumping into a hydrogen atom and getting
absorbed as it knocks the electron loose.  Now, there is not much
hydrogen in interstellar space.  There's a lot of room between
hydrogen atoms.  But over trillions upon trillions of kilometers, the
hydrogen adds up.  Beyond a few light-years, it's hard to see any
light with really short wavelengths, because it gets absorbed in the
interstellar hydrogen before it gets to us. 
 
    Consequently, the ultraviolet telescopes that have flown in space,
such as the International Ultraviolet Explorer, have not been given
the capability to see extreme ultraviolet (EUV) colors.  But the sky
isn't as opaque as people thought;  you can see *some* distance into
space in the EUV, and there is interesting physics going on in nearby
stars, especially extremely hot ones. 
 
    The Voyager UVS instruments are the only currently flying which
can make measurements in the EUV.  They are small, and their spectral
resolution is only about 100 angstroms, but they have lots of leisure
time to make long exposures these days.  So there's an ongoing program
to use the UVS to study a series of stellar targets, which, I imagine,
will continue as long as they have the power to operate them.  I'd
speculate that the Voyager studies are valuable precursors for
planning such missions as the STS-35 ASTRO observatory, carrying the
Hopkins Ultraviolet Telescope, and the Extreme Ultraviolet Explorer,
which will make an all-sky survey. 
 
    In recent months, according to the Voyager status reports, the following
targets have been studies with the UVS instruments of the two spacecraft:
 
    MU Centauri
    HD 206165
    EG165
    PKS2155-304
    Markarian 509
    HD 212571
    NGC 7027
    HD 164284
    HD 217675
    HD 200120
    HD 120324
    HD 164284
 
    (Maybe one of our astronomer friends can explain these catalog
designations?) 
 
    So you see, NASA hasn't exactly clammed up about Voyager's
activities since the Neptune encounter.  You don't read about them in
your local newspaper because they're pretty technical and routine. 
The same is true for Fermilab-- we only call a press conference when
we've got something novel to announce, not when we've completed the
fifteenth week of a fixed-target run with 122 hours of beam time... 
You can be sure that if Voyager scientists come up with something
juicy from all this raw data, the JPL or NASA public-information
people will be quick to issue a press release on it. 
 
                      ______meson   Bill Higgins
                   _-~
     ____________-~______neutrino   Fermi National Accelerator Laboratory
   -   -         ~-_
 /       \          ~----- proton   Bitnet: [email protected]
 |       |
 \       /                          SPAN/Hepnet/Physnet: 43011::HIGGINS
   -   -
     ~                              Internet: [email protected]

re .176:  Very interesting.  I wonder if someone is checking star occultations
that Voyager will be seeing. I should think it might be interesting to use the
Photopolarimeter to watch and see if there are any blinks which might indicate
planets or dust etc around the nearer star.

Burns

RE: .174  Thanks Eric.

A quick calculation indicates that if Voyager 1 continued to consume fuel at the
indicated rate (4 gm per week) it would "live" for another 175 years!  Voyager 2
for 190 years!  And those figures don't include to 2.0 Kg "reserve".  WOW!

I guess nobody wants to venture a "guess" at how far away (from Earth) the
spacecrafts are.  How about velocity relative to ... oh, pick an object, any
object!  :-)

RE: .176  Very interesting information.

...Roger...

  I think they will run out of electrical power long before that. At that
point, the fuel won't do much good.

  George

    Current rumors are that the +2 is not a reserve, but an abbreviation
    for +/- 2.   They'll still run out of electrical power first.
    
    - dave

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 05/22/90
Date: 23 May 90 03:44:44 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                    Voyager Mission Status Report
                            May 22, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data. On May 11 an Ultraviolet Spectrometer (UVS) observation
was taken on the star HD217675, and a Magnetometer calibration
(MAGCAL) and Low Energy Charged Particles (LECP) calibration (PESCAL)
were successfully executed.  The MAGCAL data from looked fine and the
LECP instrument responded correctly to its PESCAL.  The downlink
telemetry was severely degraded due to antenna pointing problems with
the 70 meter antenna in Spain (DSS 63).  Receiver lock was lost
completely for seven minutes. 
 
     On May 15 a frame of Plasma Wave (PWS) data was recorded for
playback at a later date.  This was the first exercise of Flight Data
Subsystem (FDS) Data Mode Control (FDAMO) Block Routine (BR6). 
 
     On May 16 real-time commands were transmitted to reset the
Computer Command Subsystem (CCS) clock to the FDS frame time and
perform a CCS timing test (CCSTIM).  Execution of these commands was
successful and the CCSTIM test indicated that a nominal offset (5
msec) between the FDS frame start and CCS timing chain in each
processor had been achieved. 
 
     Spacecraft performance for all of the sequenced activity during
this report period has been nominal. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  UVS high-rate data were taken on Markarian 509 on May
14 and May 17.  The two hours and 44 minutes on May 14 looked fine. 
The data from May 17 was badly degraded for the first two hours,
leaving only 3 hours and 17 minutes of usable data. 
 
     On May 15 a CCSTIM test was executed and a Attitude and
Articulation Control Subystem (AACS) patch was delinked.  The CCSTIM
test analysis indicated a nominal offset between the FDS frame start
and the CCS timing chain in each processor and the delinking of the
patch was verified by AACS memory read-out. 
 
     On May 17 real-time commands were transmitted to change the FDS
data mode, perform a full FDS memory read-out, return the FDS data
mode back to its previous state, reset the Command Loss (CMDLOS)
timer, and to enable the mini-Cruise Manuever (CRSMVR) scheduled for
May 23.  All of these commands executed nominally and the FDS memory
read-out was received. 
 
     Also on May 17 a PLSCAL/MAGCAL/PESCAL sequence were executed. 
The BAY 1 heater was turned off and X BAND TWT was configured to the
high power mode, and the AACS B and C GYROS were turned on and
initialized in preparation for the mini-CRSMVR on May 23.  The last
hour of the MAGCAL and all of the PESCAL were not received due to lack
of Deep Space Network (DSN) 70 meter support. The Plasma instrument
calibration (PLSCAL) went fine.  The thermal events (bay 1 heater
off/XTWT to high power and BC gyros on) caused a command moratorium to
be imposed that resulted in approximately one day of this period being
unavailable for acquisition of ranging or coherent Doppler data.  
 
                   CONSUMABLE STATUS AS OF 5/22/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
             Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
  Voyager 1    5              36.5 + 2.0          370         59
  Voyager 2    9              39.6 + 2.0          374         48
 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

Newsgroups: sci.space,sci.astro
Subject: Voyager 1 Images to be Unveiled
Date: 23 May 90 16:08:39 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    The "family portrait" images taken by Voyager 1 last February will
be unveiled as a wall mosaic at the Jet Propulsion Lab in Pasadena,
California, on June 6. 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____| |_|      |_____|   Pasadena, CA 91109   |

From: [email protected] (Jonathan McDowell)
Newsgroups: sci.space
Subject: Re: What Voyagers are up to...
Date: 23 May 90 15:06:06 GMT
Organization: Harvard/Smithsonian Center for Astrophysics
 
    From article <[email protected]>, by
[email protected] (Bill Higgins-- Beam Jockey): 

    > (Maybe one of our astronomer friends can explain these catalog
designations?) 
 
    OK, I gotta earn my keep somehow:
 
  * Mu Centauri		Bright star in Centaurus, Bayer letter is Mu

  * HD 206165		Star in Annie Cannon's (ca. 1920) HD catalog, the 
                        standard catalog of moderately bright stars
 
  * HD 164284		Ditto

  * HD 217675
  * HD 200120
  * HD 120324
  * HD 164284
  * HD 212571
 
  * EG165		Eggen and Greenstein white dwarf star. White dwarfs are
			faint in the visible but very bright in the extreme UV.

  * PKS2155-304		Parkes radio source; coordinates are RA = 21 55, DEC = 
                        -30.4 (1950).
			This source is a well known BL Lac object. A BL Lac 
                        object is a variety of quasar which varies rapidly 
                        and shows strong continuum without emission lines; 
                        current models suggest we are looking down the mouth 
                        of a jet of material travelling at relativistic
			speeds out of the quasar nucleus.
 
  * Markarian 509	One of the UV-bright galaxies found by Markarian and 
                        colleagues in Armenia.  This well studied galaxy 
                        contains a Seyfert nucleus (small quasar) and is 
                        very bright in the far infrared.
 
  * NGC 7027		Nebula in the New General catalog; this one is a famous
			planetary nebula, the remnant of a low mass star. The 
                        core of the star remains at the center of the nebula, 
                        a hot proto-white dwarf which is EUV-bright.
   

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 05/29/90
Date: 30 May 90 02:27:56 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                    Voyager Mission Status Report
                            May 29, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data.  Spacecraft activity was very limited this week. Plasma
Wave (PWS) data was recorded on May 22.  High-rate Ultraviolet
Spectrometer (UVS) observations of the stars HD 217675 and Markarian
335 were conducted on May 18 and May 22, respectively.  No data was
acquired during either of the two UVS high rate periods due to lack of
Deep Space Network (DSN) coverage.  On May 22, following the second UVS
high rate period, X-BAND was switched to low power and the BAY 1
HEATER was turned on.  All spacecraft activity was as expected.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  An ASCAL was performed on May 18 and one frame of
high-rate PWS data was recorded on May 22.  High-rate UVS observations
of Markarian 509 were conducted on May 21 and May 24, but, due to
limited DSN station availability, only about 30% of the total data
were acquired. 
 
     The last Cruise Maneuver was performed in the blind on May 23
because the telemetry was below the threshold limits.  The playback
the next day was fine until the station was taken for another project.
The data indicated a smooth transition through 4 of the negative yaw
turns.  The Plasma (PLS) instrument responded nominally.  The Low
Energy Charged Particles Subsystem (LECP) recorded data as well. 
 
    Thermal events on May 17 (bay 1 heater off/XTWT to high power and
BC gyros on), May 23 (Cruise Maneuver and BC gyros off), and May 24
(STWT to low power) caused command moratoria to be imposed that
resulted in approximately four and one-quarter days of this period
being unavailable for acquisition of ranging or coherent Doppler data.
 
    A PWS frame was played back on May 24 as well.
  
                   CONSUMABLE STATUS AS OF 5/29/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    5             36.4 + 2.0          370         59
   Voyager 2   54             39.5 + 2.0          374         66
 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                      June 4, 1990
(Phone:  202/453-1547)


EDITORS NOTE:  N90-40

NASA BRIEFING ON SOLAR SYSTEM IMAGE AND NEW FINDINGS  


     NASA will present new information from the Voyager missions 
to the outer planets and a portrait of the solar system at a 
press conference on June 6, 1990, at 2 p.m. EDT, NASA 
Headquarters auditorium, 400 Md. Ave., S.W., Washington, D.C.

     Voyager Project Scientist Dr. Edward C. Stone of California 
Institute of Technology, Pasadena, Calif., will discuss the 
findings of Voyagers 1 and 2 obtained by the two spacecraft at 
Jupiter, Saturn, Uranus and Neptune between 1979 and 1989.

     Dr. Stone also will reveal a portrait of the solar system 
(Sun, Venus, Earth, Jupiter, Saturn, Uranus and Neptune) taken by 
Voyager 1 last Feb. 14, when the spacecraft was 3.7 billion miles 
from Earth.  Dr. Carl Sagan, Cornell Univ., Ithaca, N.Y., will 
remark on the image as well.  In addition, a new, 5-minute video 
will be shown, recapping the voyage to the outer planets and 
demonstrating how the image of the solar system was taken.

     The conference will be carried live on NASA Select 
television, Satcom F-2R, transponder 13, 72 degrees W. longitude, 
with 2-way question and answer capability.


From: [email protected] (Peter E. Yee)
Newsgroups: sci.space
Subject: NASA briefing on solar system image and new findings (Forwarded)
Date: 4 Jun 90 18:26:14 GMT
Organization: NASA Ames Research Center, Moffett Field, CA

	WASHINGTON (UPI) -- A historic photo from NASA's aging Voyager 1
probe showing Earth and five of its planetary neighbors as tiny dots in
the vast blackness of space graphically shows just ``how insignificant
we are,'' a NASA spokesman said Tuesday.
	NASA planned to release a series of black-and-white photos crafted
into a mosaic along with several color portraits of individual planets
at a news conference Wednesday. The photographs will be discussed by
scientist Edward Stone of the California Institute of Technology and
astronomer Carl Sagan of Cornell University in Ithaca, N.Y.
	The pictures are among more than 60 images taken Feb. 13 by Voyager
1 as the hardy probe sailed toward the outer reaches of the solar
system, providing a once-in-a-lifetime alien's eye view of Earth's home.
	``I think historically it's a heck of a good thing. We most likely
will never be in a position to do that again,'' said Jurrie van der
Woude, a spokesman for the Jet Propulsion Laboratory in Pasadena, Calif.
	``Most likely it's the only shot ever that we can see that we ever
got looking back at our own solar system,'' he said. ``It's our
neighborhood.''
	An 8-by-10-inch black and white mosaic shows Earth, Venus, Jupiter,
Saturn Uranus and Neptune and the sun as tiny dots against a vast black
background, he said in describing the pictures.
	``It shows you how insignificant we are,'' van der Woude said. ``It
may not be a photograph that makes you say, `Wow.' But when you look at
it, it's a sobering thought that we're so small.''
	The image does not include Pluto because it was out of Voyager's
field of view. Mercury and Mars also are missing because they were both
too close to the sun as viewed by Voyager.
	Voyager 1 was launched 13 years ago this September. Two television
cameras aboard the craft took the priceless pictures over a four-hour
period starting at 8:12 p.m. EST Feb. 13. The United States was facing
away from the spacecraft at the time the pictures were taken.
	The images were stored on magnetic tape and radioed back to Earth
over an 11-day period starting March 16. It took Voyager 30 minutes to
transmit each photo to the home planet and the signals, traveling at
186,000 miles per second, took more than 5 1/2 hours to complete the trip.
	Traveling at 65 mph, it would take a motorist some 6,500 years to
reach Voyager 1's photo position.
	Voyager 1 currently is cruising toward the edge of the solar system
on an endless space odyssey and is about 2 billion miles above the plane
of the solar system.
	For Candy Hansen, the imaging expert in charge of the photo
project, the ``picture of the century'' represents stirring glimpse of
humanity's home in the limitless reaches of space.
	``It's almost gotten to be trite, the old stuff about `planet
Earth,' and `spaceship Earth,''' Hansen said before the photos were
taken. ``But to have something that graphically demonstrates this little
teeny, tiny, fragile body out there amongst its neighbors, I think, is
going to be a powerful statement.''


From: [email protected] (ROB STEIN, UPI Science Editor)
Newsgroups: clari.tw.space
Subject: `Picture of the century' set for release
Keywords: space, science, air transport, transportation
Message-ID: <[email protected]>
Date: 5 Jun 90 20:02:24 GMT

	Does anyone know how to get prints of the "Picture"?

	Regards, Robert.

    Re:.186
    	There is no information available yet on how to obtain this family
    portrait. It could be unobtainable: In order to get a good reproduction
    that shows anything (remember that these photos will show nothing but
    dim points of light), a mosaic about 40 FEET long is needed. Individual
    narrow angle color photos of each planet may be possible to get
    (although they'll be pretty unimpressive) or maybe even a single photo
    of the entire mosaic (which will show the Sun and a few bright stars if
    it is a good copy) but don't hold your breath.
    	If it does become available, I'll post an address.
    
    				Drew
    
    

    The press conference to officially announce it, along with some 'new
    findings' takes place today.
    
    gary

From: [email protected] (Steve Groom)
Newsgroups: sci.space,sci.astro
Subject: Voyager Mission Summary (forwarded)
Date: 6 Jun 90 17:46:41 GMT
Sender: [email protected] (Usenet)
Organization: Image Analysis Systems Grp, JPL
 
    This fact sheet was posted to an internal NASA newsgroup in support
of today's press conference covering the Voyager missions to the outer
planets.  I thought it was a very good summary and worth reposting here.
 
-steve
[email protected]
 
------------------------------------------------------------------------
 
	THE VOYAGER MISSION:  A SUMMARY
 
     The twin spacecraft Voyager 1 and Voyager 2 were launched by 
NASA during the summer of 1977 from Cape Canaveral, Fla.  As 
originally designed, the Voyagers were to conduct closeup studies 
of Jupiter and Saturn, Saturn's rings and the larger moons of the 
two planets. 
 
     To accomplish their two-planet mission, the spacecraft were 
built to last 5 years.  But as the mission went on and with the 
successful achievement of all its objectives, the additional 
flybys of the two outermost giant planets, Uranus and Neptune, 
proved possible -- and irresistible -- to mission scientists and 
engineers at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
 
     As the spacecraft flew across the solar system, remote-
control reprogramming was used to endow the Voyagers with greater 
capabilities than they possessed when they left Earth.  Their 
two-planet mission became four.  Their 5-year lifetimes stretched 
to 12 and more.
 
     Eventually, between them, Voyagers 1 and 2 would explore all the
giant outer planets of our solar system, 48 of their moons and the
unique systems of rings and magnetic fields those planets possess. 
 
     Had the Voyager missions ended after the Jupiter and Saturn 
flybys, they still would have provided the material to rewrite 
astronomy textbooks.  But having doubled their already ambitious 
itineraries, the Voyagers returned to Earth information that has 
revolutionized the science of planetary astronomy, helping to 
resolve key questions while raising intriguing new ones about the 
origin and evolution of the planets in this solar system.
 
	HISTORY OF THE VOYAGER MISSION
 
     The Voyager mission was designed to take advantage of a rare
geometric arrangement of the outer planets in the late 1970s and the
early 1980s.  This layout of Jupiter, Saturn, Uranus and Neptune,
which occurs about every 175 years, allows a spacecraft on a
particular flight path to swing from one planet to the next without
the need for large onboard propulsion systems.  The flyby of each
planet bends the spacecraft's flight path and increases its velocity
enough to deliver the spacecraft to the next destination.  Using this
"gravity assist" technique, the flight time to Neptune can be reduced
from 30 years to 12. 
 
     While the four-planet mission was known to be possible, it was
deemed too expensive to build a spacecraft that could go the distance,
carry the instruments needed and last long enough to accomplish such a
lengthy mission.  Thus, the Voyagers were funded to conduct intensive
flyby studies of Jupiter and Saturn only. 
 
     More than 10,000 trajectories were studied before choosing 
the two that would allow close flybys of Jupiter and its large 
moon Io and Saturn and its large moon Titan.  The chosen flight 
path for Voyager 2 also preserved the option to continue on to 
Uranus and Neptune.  
 
     NASA managed the launch of both Voyagers from the Cape 
Canaveral Air Force Station, Fla.  Voyager 2 was launched on Aug. 
20, 1977; Voyager 1 was launched on a faster, shorter trajectory 
Sept. 5, 1977.  Both spacecraft were delivered to space aboard 
Titan-Centaur expendable rockets.
 
     The prime Voyager mission to Jupiter and Saturn brought 
Voyager 1 to Jupiter on March 5, 1979, and to Saturn on Nov. 12, 
1980, followed by Voyager 2 to Jupiter on July 9, 1979, and 
Saturn on Aug. 25, 1981.
 
     Voyager 1's trajectory, designed to send the spacecraft 
closely past the large moon Titan and behind Saturn's rings, bent 
the spacecraft's path inexorably northward out of the ecliptic 
plane -- the plane in which most of the planets orbit the Sun.  
Voyager 2 was aimed to fly by Saturn at a point that would 
automatically send the spacecraft in the direction of Uranus.  
 
     After Voyager 2's successful Saturn encounter, it was shown 
that Voyager 2 likely would be able to fly on to Uranus with all 
instruments operating.  NASA provided additional funding to 
continue operating the two spacecraft and authorized JPL to 
conduct a Uranus flyby.  Subsequently, NASA also authorized the 
Neptune leg of the mission, which was renamed the Voyager Neptune.
Interstellar Mission
 
     Voyager 2 encountered Uranus on Jan. 24, 1986, returning 
detailed photos and other data on the planet, its moons, magnetic 
field and dark rings.  Voyager 1, meanwhile, continued to press 
outward, conducting studies of interplanetary space.  Eventually, 
its instruments may be the first of any spacecraft to sense the 
heliopause -- the boundary between the end of the Sun's magnetic 
influence and the beginning of interstellar space. 
 
     Following Voyager 2's closest approach to Neptune on Aug. 
25, 1989, the spacecraft flew southward, below the ecliptic plane 
and onto a course that will take it to interstellar space as 
well.  Reflecting the Voyagers' new transplanetary destinations, 
the project is now known as the Voyager Interstellar Mission. 
 
     Voyager 1 is now leaving the solar system, rising above the 
ecliptic plane at an angle of about 35 degrees at a rate of about 
520 million kilometers (about 320 million miles) a year.  Voyager 
2 also is headed out of the solar system, diving below the 
ecliptic plane at an angle of about 48 degrees and a rate of 
about 470 million kilometers (about 290 million miles) a year.
 
     Both spacecraft will continue to study ultraviolet sources 
among the stars, and the fields and particles instruments aboard 
the Voyagers will continue to search for the boundary between the 
Sun's influence and interstellar space.  The Voyagers are 
expected to return valuable data for two or three more decades.  
Communications will be maintained until the Voyagers' nuclear 
power sources can no longer supply enough electrical energy to 
power critical subsystems.
 
     The cost of the Voyager 1 and 2 missions -- including 
launch, mission operations from launch through the Neptune 
encounter and the spacecraft's nuclear batteries (provided by the 
Department of Energy) -- is $865 million.  NASA budgeted an 
additional $30 million to fund the Voyager Interstellar Mission 
for 2 years following the Neptune encounter.
 
	VOYAGER OPERATIONS
 
     Voyagers 1 and 2 are identical spacecraft.  Each is equipped 
with instruments to conduct 10 different experiments.  The 
instruments include television cameras, infrared and ultraviolet 
sensors, magnetometers, plasma detectors and cosmic-ray and 
charged-particle sensors.  In addition, the spacecraft radio is 
used to conduct experiments. 
 
     The Voyagers travel too far from the Sun to use solar 
panels.  Instead, they were equipped with power sources called 
radioisotope thermoelectric generators (RTGs).  These RTGs, used 
on other deep space missions, convert the heat, produced from the 
natural radioactive decay of plutonium, into electricity to power 
the spacecraft instruments, computers, radio and other systems.
 
     The spacecraft are controlled and their data returned 
through the Deep Space Network (DSN), a global spacecraft 
tracking system operated by JPL for NASA.  DSN antenna complexes 
are located in California's Mojave Desert; near Madrid, Spain; 
and in Tidbinbilla, near Canberra, Australia.
 
     The Voyager project manager for the Interstellar Mission is 
George P. Textor of JPL.  The Voyager project scientist is Dr. 
Edward C. Stone of the California Institute of Technology.  The 
assistant project scientist for the Jupiter flyby was Dr. Arthur 
L. Lane, followed by Dr. Ellis D. Miner for the Saturn, Uranus 
and Neptune encounters.  Both are with JPL.  The Voyager program 
manager at NASA Headquarters, Washington, D.C., is Ann Merwarth.
 
	JUPITER
 
     Voyager 1 made its closest approach to Jupiter on March 5, 
1979, and Voyager 2 followed with its closest approach occurring 
on July 9, 1979.  The first spacecraft flew within 206,700 
kilometers (128,400 miles) of the planet's cloud tops, and 
Voyager 2 came within 570,000 kilometers (350,000 miles).
 
     Jupiter is the largest planet in the solar system, composed 
mainly of hydrogen and helium, with small amounts of methane, 
ammonia, water vapor, traces of other compounds and a core of 
melted rock and ice.  Colorful latitudinal bands and atmospheric 
clouds and storms illustrate Jupiter's dynamic weather system.  
The giant planet is now known to possess 16 moons.  The planet 
completes one orbit of the Sun each 11.8 years and its day is 9 
hours, 55 minutes.
 
     Although astronomers had studied Jupiter through telescopes 
on Earth for centuries, scientists were surprised by many of the 
Voyager findings.  The Great Red Spot was revealed as a complex 
storm moving in a counterclockwise direction.  An array of other 
smaller storms and eddies were found throughout the banded clouds.  
 
     Discovery of active volcanism on the satellite Io was easily 
the greatest unexpected discovery at Jupiter.  It was the first 
time active volcanoes had been seen on another body in the solar 
system.  Together, the Voyagers observed the eruption of nine 
volcanoes on Io, and there is evidence that other eruptions 
occurred between the Voyager encounters.
 
     Plumes from the volcanoes extend to more than 300 kilometers 
(190 miles) above the surface.  The Voyagers observed material 
ejected at velocities up to a kilometer per second.
 
     Io's volcanoes are apparently due to heating of the 
satellite by tidal pumping.  Io is perturbed in its orbit by 
Europa and Ganymede, two other large satellites nearby, then 
pulled back again into its regular orbit by Jupiter.  This tug-
of-war results in tidal bulging as great as 100 meters (330 feet) 
on Io's surface, compared with typical tidal bulges on Earth of 
one meter (3 feet).
 
     It appears that volcanism on Io affects the entire jovian 
system, in that it is the primary source of matter that pervades 
Jupiter's magnetosphere, the region of space surrounding the 
planet influenced by the jovian magnetic field.  Sulfur, oxygen 
and sodium, apparently erupted by Io's many volcanoes and 
sputtered off the surface by impact of high-energy particles, 
were detected as far away as the outer edge of the magnetosphere 
millions of miles from the planet itself.
  
     Europa displayed a large number of intersecting linear 
features in the low-resolution photos from Voyager 1.  At first, 
scientists believed the features might be deep cracks caused by 
crustal rifting or tectonic processes.  The closer high-
resolution photos from Voyager 2, however, left scientists 
puzzled.  The features were so lacking in topographic relief that 
as one scientist described them, they "might have been painted on 
with a felt marker."  
 
     There is a possibility that Europa may be internally active 
due to tidal heating at a level one-tenth or less than that of 
Io.  Europa is thought to have a thin crust (less than 30 
kilometers or 18 miles thick) of water ice, possibly floating on 
a 50-kilometer-deep (30-mile) ocean.
 
     Ganymede turned out to be the largest moon in the solar 
system, with a diameter measuring 5,276 kilometers (3,280 
miles).  It showed two distinct types of terrain, cratered and 
grooved, suggesting to scientists that Ganymede's entire icy 
crust has been under tension from global tectonic processes.
 
     Callisto has a very old, heavily cratered crust showing remnant
rings of enormous impact craters.  The largest craters apparently have
been erased by the flow of icy crust over geologic time.  Almost no
topographic relief is apparent in the ghost remnants of the immense
impact basins, identifiable only by their light color and the
surrounding subdued rings of concentric ridges. 
 
     A faint, dusty ring of material was found around Jupiter.  
Its outer edge is 129,000 kilometers (80,000 miles) from the 
center of the planet, and it extends inward about 30,000 
kilometers (18,000 miles).
 
     Two new, small satellites, Adrastea and Metis, were found 
orbiting just outside the ring.  A third new satellite, Thebe, 
was discovered between the orbits of Amalthea and Io.
 
     Jupiter's rings and moons exist within an intense radiation 
belt of electrons and ions trapped in the planet's magnetic 
field.  These particles and fields comprise the jovian 
magnetosphere or magnetic environment, which extends 3 to 7 
million kilometers toward the Sun, and stretches in a windsock 
shape at least as far as Saturn's orbit -- a distance of 750 
million kilometers (460 million miles).
 
     As the magnetosphere rotates with Jupiter, it sweeps past Io 
and strips away about 1,000 kilograms (1 ton) of material per 
second.  The material forms a torus, a doughnut-shaped cloud of 
ions that glow in the ultraviolet.  The torus's heavy ions 
migrate outward, and their pressure inflates the jovian 
magnetosphere to more than twice its expected size.  Some of the 
more energetic sulfur and oxygen ions fall along the magnetic 
field into the planet's atmosphere, resulting in auroras.
 
     Io acts as an electrical generator as it moves through 
Jupiter's magnetic field, developing 400,000 volts across its 
diameter and generating an electric current of 3 million amperes 
that flows along the magnetic field to the planet's ionosphere.
 
	SATURN
 
     The Voyager 1 and 2 Saturn flybys occurred 9 months apart, with
the closest approaches falling on Nov. 12 and Aug. 25, 1981. Voyager 1
flew within 64,200 kilometers (40,000 miles) of the cloud tops, while
Voyager 2 came within 41,000 kilometers (26,000 miles). 
 
      Saturn is the second largest planet in the solar system.  
It takes 29.5 Earth years to complete one orbit of the Sun, and 
its day is clocked at 10 hours, 39 minutes.  Saturn is known to 
have at least 17 moons and a complex ring system.  Like Jupiter, 
Saturn is mostly hydrogen and helium.  Its hazy yellow hue was 
found to be marked by broad atmospheric banding similar to but 
much fainter than that found on Jupiter.  Close scrutiny by 
Voyager's imaging systems revealed long-lived ovals and other 
atmospheric features generally smaller than those on Jupiter.
 
     Perhaps the greatest surprises and the most puzzling were 
found by the Voyagers in Saturn's rings.  It is thought that the 
rings formed from larger moons that were shattered by impacts of 
comets and meteoroids.  The resulting dust and boulder- to house-
size particles have accumulated in a broad plane around the 
planet varying in density.  
 
     The irregular shapes of Saturn's eight smallest moons 
indicates that they too are fragments of larger bodies.  
Unexpected structure such as kinks and spokes were found in 
addition to thin rings and broad, diffuse rings not observed from 
Earth.  Much of the elaborate structure of some of the rings is 
due to the gravitational effects of nearby satellites.  This 
phenomenon is most obviously demonstrated by the relationship 
between the F-ring and two small moons that "shepherd" the ring 
material.  The variation in the separation of the moons from the 
ring may explain the ring's kinked appearance.  Shepherding moons 
also were found by Voyager 2 at Uranus.
 
     Radial, spokelike features in the broad B-ring also were 
found by the Voyagers.  The features are believed to be composed 
of fine, dust-size particles.  The spokes were observed to form 
and dissipate in time-lapse images taken by the Voyagers.  While 
electrostatic charging may create spokes by levitating dust 
particles above the ring, the exact cause of the formation of the 
spokes is not well understood.
 
     Winds blow at extremely high speeds on Saturn -- up to 1,800 
kilometers per hour (1,100 miles per hour).  Their primarily 
easterly direction indicates that the winds are not confined to 
the top cloud layer but must extend at least 2,000 kilometers 
(1,200 miles) downward into the atmosphere.  The characteristic 
temperature of the atmosphere is 95 degrees kelvins.
 
     Saturn holds a wide assortment of satellites in its orbit 
ranging from Phoebe, a small moon that travels in a retrograde 
orbit and probably is a captured asteroid, to Titan, the planet-
sized moon with a thick nitrogen-methane atmosphere.  Titan's 
surface temperature and pressure are 94 degrees kelvins (-292 
degrees Fahrenheit) and 1.5 atmospheres.  
 
     Photochemistry converts some atmospheric methane to other 
organic molecules, such as ethane, that is thought to accumulate 
in lakes or oceans.  Other more complex hydrocarbons form the 
haze particles that eventually fall to the surface, coating it 
with a thick layer of organic matter.  The chemistry in Titan's 
atmosphere may strongly resemble that which occurred on Earth 
before life evolved.
 
     The most active surface of any moon seen in the Saturn 
system was that of Enceladus.  The bright surface of this moon, 
marked by faults and valleys, showed evidence of tectonically 
induced change.  Voyager 1 found the moon Mimas scarred with a 
crater so huge that the impact that caused it nearly broke the 
satellite apart.
 
     Saturn's magnetic field is smaller than Jupiter's, extending 
only 1 or 2 million kilometers.  The axis of the field is almost 
perfectly aligned with the rotation axis of the planet.  
 
	URANUS
 
     In its first solo planetary flyby, Voyager 2 made its 
closest approach to Uranus on Jan. 24, 1986, coming within 81,500 
kilometers (50,600 miles) of the planet's cloud tops.
 
     Uranus is the third largest planet in the solar system.  It 
orbits the Sun at a distance of about 2.8 billion kilometers (1.7 
billion miles) and completes one orbit every 84 years.  The 
length of a day on Uranus as measured by Voyager 2 is 17 hours, 
14 minutes.
 
     Uranus is distinguished by the fact that it is tipped on its 
side.  Its unusual position is thought to be the result of a 
collision with a planet-sized body early in the solar system's 
history.  Given its odd orientation with its polar regions 
exposed to sunlight or darkness for long periods, scientists were 
not sure what to expect at Uranus. 
 
     Voyager 2 found that one of the most striking influences of 
this sideways position is its effect on the tail of the magnetic 
field, which is itself tilted 60 degrees from the the planet's 
axis of rotation.  The magnetotail was shown to be twisted by the 
planet's rotation into a long corkscrew shape behind the planet.
 
     The presence of a magnetic field at Uranus was not known 
until Voyager's arrival.  The intensity of the field is roughly 
comparable to that of Earth's, though it varies much more from 
point to point because of its large offset from the center of 
Uranus.  The peculiar orientation of the magnetic field suggests 
that the field is generated at an intermediate depth in the 
interior where the pressure is high enough for water to become 
electrically conducting.
 
     The intensity of radiation within Saturn's radiation belts 
is such that any methane trapped in the icy surfaces of the inner 
moons and ring particles would quickly darken (within 100,000 
years).  This may have contributed to the darkened surfaces of 
the moons and ring particles, which are almost uniformly gray.
 
     A high layer of haze was detected around the sunlit pole, 
which also was found to radiate large amounts of ultraviolet 
light, a phenomenon dubbed "dayglow."  The average temperature is 
about 60 degrees kelvin (-350 degrees Fahrenheit).  Surprisingly, 
the illuminated and dark poles, and most of the planet, show 
nearly the same temperature at the cloud tops.
 
     Voyager found 10 new moons, bringing the total number to 
15.  Most of the new moons are small, with the largest measuring 
about 150 kilometers (about 90 miles) in diameter.  The moon 
Miranda, innermost of the five large moons, was revealed to be 
one of the strangest bodies yet seen in the solar system.  
Detailed images from Voyager's flyby of the moon showed huge 
fault canyons as deep as 20 kilometers (12 miles), terraced 
layers and a mixture of old and young surfaces.  One theory holds 
that Miranda may be a reaggregration of material from an earlier 
time when the moon was fractured by an violent impact. 
 
     The five large moons appear to be ice-rock conglomerates 
like the satellites of Saturn.  Titania is marked by huge fault 
systems and canyons indicating some degree of geologic, probably 
tectonic, activity in its history.  Ariel has the brightest and 
possibly youngest surface of all the Uranian moons and also 
appears to have undergone geologic activity that led to many 
fault valleys and what seem to be extensive flows of icy 
material.  Little geologic activity has occurred on Umbriel or 
Oberon, judging by their old and dark surfaces.
 
     All nine previously known rings were studied showing the 
Uranian rings to be distinctly different from those at Jupiter 
and Saturn.  The ring system may be relatively young and did not 
form at the same time as Uranus.  Particles that make up the 
rings may be remnants of a moon that was broken by a high-
velocity impact or torn up by gravitational effects.
 
	NEPTUNE
 
     When Voyager flew within 5,000 kilometers (3,000 miles) of 
Neptune on Aug. 25, 1989, the planet was the most distant member 
of the solar system from the Sun.  (Pluto once again will become 
most distant in 1999.)
 
     Neptune orbits the Sun every 165 years.  It is the smallest
planet of this solar system's gas giants.  Neptune is now known to
have eight moons, six of which were found by Voyager.  The length of 
a Neptunian day has been determined to be 16 hours, 6.7 minutes. 
 
     Even though Neptune receives only three percent as much 
sunlight as Jupiter does, it is a dynamic planet and surprisingly 
showed several large, dark spots reminiscent of Jupiter's 
hurricane-like storms.  The largest spot, dubbed the Great Dark 
Spot, is about the size of Earth and is similar to the Great Red 
Spot on Jupiter.  A small, irregularly shaped, eastward-moving 
cloud was observed "scooting" around Neptune every 16 hours or 
so; this "scooter," as Voyager scientists called it, could be a 
cloud plume rising above a deeper cloud deck.
 
     Long, bright clouds, similar to cirrus clouds on Earth, were 
seen high in Neptune's atmosphere.  At low northern latitudes, 
Voyager captured images of cloud streaks casting their shadows on 
cloud decks below.
 
     The strongest winds on any planet were measured on 
Neptune.  Most of the winds there blow westward, opposite to the 
rotation of the planet.  Near the Great Dark Spot, winds blow up 
to 2,000 kilometers (1,200 miles) an hour.
 
     The magnetic field of Neptune, like that of Uranus, turned 
out to be highly tilted -- 47 degrees from the rotation axis and 
offset at least 0.55 radii (about 13,500 kilometers or 8,500 
miles) from the physical center.  Comparing the magnetic fields 
of the two planets, scientists think the extreme orientation may 
be characteristic of flows in the interiors of both Uranus and 
Neptune -- and not the result, in Uranus's case, of that planet's 
sideways orientation or of any possible field reversals at either 
planet.  
 
     Voyager's studies of radio waves caused by the magnetic 
field revealed the length of a Neptunian day.  The spacecraft 
also detected auroras, but much weaker than those on Earth and 
other planets.
 
     Triton, the largest of the moons of Neptune, was shown to be not
only the most intriguing satellite of the Neptunian system, but one of
the most interesting in all the solar system.  It shows evidence of a
remarkable geologic history, and Voyager 2 images showed active
geyser-like eruptions spewing invisible nitrogen gas and dark dust
particles several kilometers into the tenuous atmosphere.  Triton's
relatively high density and retrograde orbit offer strong evidence
that Triton is not an original member of Neptune's family but is a
captured object.  If that is the case, tidal heating could have melted
Triton in its originally eccentric orbit, and the moon might even have
been liquid for as long as one billion years after its capture by Neptune. 
 
     An extremely thin atmosphere extends about 800 kilometer 
(500 miles) above Triton's surface.  Nitrogen ice particles may 
form thin clouds a few kilometers above the surface.  The 
atmospheric pressure at the surface is about 14 microbars, 
1/70,000th the surface pressure on Earth.  The surface 
temperature is about 38 degrees kelvin (-391 degrees Fahrenheit) 
the coldest temperature of any body known in the solar system.
 
     The new moons found at Neptune by Voyager are all small and 
remain close to Neptune's equatorial plane.  Names selected from 
mythology's water deities will be given Neptune's newest moons by 
the International Astronomical Union.
 
     Voyager 2 solved many of the questions scientists had about 
Neptune's rings.  Searches for "ring arcs," or partial rings, 
showed that Neptune's rings actually are complete, but are so 
diffuse and the material in them so fine that they could not be 
fully resolved from Earth.  From the outermost in, the rings have 
been designated 1989N1R, 1984N4R, 1989N2R, and 1989N3R.
 
    Statistics
 
            Diameter                           Distance from Sun

Jupiter     142,984 km/88,846 mi    778,000,000 km/483,000,000 mi
 
Jupiter's Moons                       Distance From Planet Center

Metis       40 km/25 mi                      128,000 km/79,500 mi
Adrastea    24x20x14 km/14x12x9 mi           129,000 km/80,100 mi
Amalthea    270x166x150 km/165x103x95 mi    181,300 km/112,600 mi
Thebe       110x90km/65x55 mi               222,000 km/138,000 mi
Io          3,630 km/2,225 mi               422,000 km/262,000 mi
Europa      3,138 km/1,949 mi               661,000 km/414,500 mi
Ganymede    5,262 km/3,269 mi             1,070,000 km/664,900 mi
Callisto    4,800 km/3,000 mi            1,883,000 km/1,170000 mi
Leda        16 km/10 mi                11,094,000 km/6,900,000 mi
Himalia     186 km/115 mi              11,480,000 km/7,133,000 mi
Lysithia    36 km/20 mi                11,720,000 km/7,282,000 mi
Elara       76 km/47 mi                11,737,000 km/7,293,000 mi
Ananke      30/18 mi                  21,200,000 km/13,173,000 mi
Carme       40 km/25 mi               22,600,000 km/14,043,000 mi
Pasiphae    50 km/31 mi               23,500,000 km/14,602,000 mi
Sinope      36 km/22 mi               23,700,000 km/14,727,000 mi
 
            Diameter                            Distance from Sun

Saturn      120,536 km/74,900 mi   1.4  billion km/870 million mi
 
Saturn's Moons                        Distance from Planet Center

Atlas       40x20 km/24x12 mi                137,670 km/85,500 mi
Prometheus  140x100x80 km/85x60x50 mi        139,353 km/86,600 mi
Pandora     110x90x80 km/70x55x50 mi         141,700 km/88,500 mi
Epimetheus  140x120x100 km/85x70x60 mi.      151,472 km/94,124 mi
Janus       220x200x160 km/135x125x100 mi.   151,422 km/94,093 mi
Mimas       392 km/243 mi                   185,520 km/115,295 mi
Enceladus   520 km/320 mi                   238,020 km/147,900 mi
Tethys      1,060 km/660 km                 294,660 km/183,100 mi
Telesto     34x28x26 km/20x17x16 mi         294,660 km/183,100 mi
Calypso     34x22x22 km/20x13x13 mi         294,660 km/183,100 mi
Dione       1,120 km/695 mi                 377,400 km/234,500 mi
Helene      36x32x30 km/22x20x19 mi         377,400 km/234,900 mi
Rhea        1,530 km/950 mi                 527,040 km/327,500 mi
Titan       5,150 km/3,200 mi             1,221,860 km/759,300 mi
Hyperion    410x260x220 km/250x155x135 mi 1,481,000 km/920,300 mi
Iapetus     1,460 km/910 mi             3,560,830 km/2,212,900 mi
Phoebe      220 km/135 mi              12,952,000 km/8,048,000 mi
  
            Diameter                           Distance from Sun

Uranus      51,118 km/31,764 mi       3 billion km/1.8 billion mi
 
Uranus's Moons:                       Distance from Planet Center

Cordelia      26 km/16 mi                     49,800 km/30,950 mi
Ophelia       30 km/18 mi                     53,800 km/33,400 mi
Bianca        42 km/26 mi                     59,200 km/36,800 mi
Juliet        62 km/38 mi                     61,800 km/38,400 mi
Desdemona     54 km/33 mi                     62,700 km/38,960 mi
Rosalind      84 km/52 mi                     64,400 km/40,000 mi
Portia       108 km/67 mi                     66,100 km/41,100 mi
Cressida      54 km/32 mi                     69,900 km/43,400 mi
Belinda       66 km/40 mi                     75,300 km/46,700 mi
Puck         154 km/95 mi                     86,000 km/53,000 mi
Miranda     472 km/293 mi                    129,900 km/80,650 mi
Ariel     1,158 km/720 mi                   190,900 km/118,835 mi
Umbriel   1,172 km/728 mi                   265,969 km/165,300 mi
Titania   1,580 km/981 mi                   436,300 km/271,100 mi
Oberon    1,524 km/947 mi                   583,400 km/362,500 mi
  
            Diameter                            Distance from Sun

Neptune     49,528 km/30,776 mi     4.5 billion km/2.7 billion mi
 
Neptune's Moons:                      Distance from Planet Center

1989N6        54 km/33 mi                     48,000 km/29,827 mi
1989N5        80 km/50 mi                     50,000 km/31,000 mi
1989N3      180 km/110 mi                     52,500 km/32,600 mi
1989N4       150 km/95 mi                     62,000 km/38,525 mi
1989N2      190 km/120 mi                     73,600 km/45,700 mi
1989N1      400 km/250 mi                    117,600 km/73,075 mi
Triton  2,700 km/1,680 mi                    354,760km/220,500 mi
Nereid      340 km/210 mi               5,509,090 km/3,423,000 mi
 
Paula Cleggett-Haleim               Mary Beth Murrill
Headquarters, Washington, D.C.      JPL, Pasadena, Calif.
(Phone:  202/453-1547)              (Phone:  818/354-5011)
 
JUNE 6, 1990
 
Steve Groom, Jet Propulsion Laboratory, Pasadena, CA
[email protected]  {ames,usc}!elroy!stevo

Newsgroups: sci.space,sci.astro
Subject: Voyager 1 Images Revealed
Date: 7 Jun 90 20:58:46 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      Voyager 1 Images Revealed
 
     Yesterday, NASA unveiled the historic "family portrait" of the
planets taken from 3.7 billion miles away by Voyager 1.  A series of
64 black-and-white photos were crafted into a mosaic and serveral
several color portraits of individual planets were also shown. 
 
     Voyager 1 photographed the images of the solar system February
14, at a point 32 degrees above the plane of the Sun's equator and
scientists at the Jet Propulsion Laboratory compressed the images in a
single photo, removing vast empty spaces that would have extended the
montage to 100 feet or more. 
 
     The portrait includes the Sun, Venus, Earth, Jupiter, Saturn,
Uranus and Neptune but Mercury was too close to the Sun and Mars was
omitted because its position made it appear as a sliver of a crescent.
       _   _____    _
      | | |  __ \  | |       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.interest.history
Subject: Solar system `family portrait' released
Date: 7 Jun 90 10:12:31 GMT

	WASHINGTON (UPI) -- A historic but ``humbling'' photograph of the
solar system  taken from deep space showed Earth and its planetary
neighbors as mere pinpoints of light in the ``velvet blackness of space.''

	``Astronomy has always been said to be a humbling experience,''
said astronomer Carl Sagan of Cornell University in Ithaca, N.Y. ``I
think this picture underscores that point.''

	The 8-by-10-inch black-and-white photograh was taken Feb. 13 by
Voyager 1 as the nuclear-powered space probe soared out of the solar
system on an endless odyssey after completing a revolutionary
exploration of the solar system.

	It was released Wednesday.

	The photograph, dubbed the ``picture of the century'' by some
astronomers, is a mosaic made up of 60 images taken by Voyager nearly 4
billion miles from Earth, and is probably the last image it will ever take.

	In the mosaic, which cost about $200,000 to produce, Earth, Venus,
Saturn, Neptune and Jupiter appear as tiny points of light arranged
around a much larger white sun.

	Because of a coincidental technical fluke, Earth appears to be in
the midst of a huge sunbeam. Mercury, Mars and Pluto, on the other hand,
were not visible from Voyager 1's perspective.

	``On that blue dot, that's where everyone you know and everyone you
ever heard of and every human being who ever lived lived out their
lives,'' Sagan said at a news conference at NASA headquarters.

	``It's a very small stage in a great cosmic arena. And again, just
speaking for myself, I think this perspective underscores our
responsibility to preserve and cherish that blue dot, the only home we
have,'' he said.

	No other photographs have ever been taken of the solar system from
that far away and no other space probes are planned that could capture
such images, said project scientist Edward Stone.

	``This was Voyager's last light,'' said Stone, a scientist from the
California Institute of Technology in Pasadena, Calif.

	Voyager 1 and its companion space probe, Voyager 2, are sailing
into deep space, searching for the boundary of the solar system where
the million-mile-per-hour solar wind interacts with dust and gas in the
interstellar medium.

	Launched in 1977, the Voyagers produced many new discoveries but
were unable to find any evidence of extraterrestrial life.

	``There is no evidence -- not a smidgen of evidence -- suggesting
life anywhere else. And for me, that underscores the rarity and
preciousness of the Earth and the life upon it,'' Sagan said.

	``The portrait of the planets that has now been taken is, it seems
to me, in the same tradition as the extraordinary photographs of the
whole Earth taken by the Apollo astronauts on their way to the moon,
which for the first time gave everyone a sense of the Earth as a small
blue-and-white world set in the velvet blackness of space,'' he said.

	``For many people, it underlines the vulnerability and fragility of
the Earth. It seems to me this portrait of the solar system has some
similar feeling.''

	Two television cameras aboard the craft took the pictures over a
four-hour period starting at 8:12 p.m. EST Feb. 13. The United States
was facing away from the spacecraft at the time the pictures were taken.

	The images were stored on magnetic tape and radioed to Earth over
an 11-day period starting March 16. It took Voyager 30 minutes to
transmit each photo and the signals, traveling at 186,000 miles per
second, took more than 5 1/2 hours to complete the trip.

The latest issue of Aviation Week has a series of six 2-inch square photos of
the planets which compose the portrait.  I must say, ho-hum!  Maybe when
composited together it's more meaningful.

The picture taken by one of the voyagers shortly after launch, looking back on
the Earth-Moon pair (far enough away to give good perspective but still with
recognizable surface detail) is much more stirring to me.
						-- Tom

  Yeh, I agree. I've seen my old VT100 come up with more dramatic displays.

  I think that what they mean is that the pictures represent something
spectacular not that they are spectacular.

  George

RE:                     <<< Note 532.192 by 25453::MAIEWSKI >>>

>  I think that what they mean is that the pictures represent something
>spectacular not that they are spectacular.

Yes, I understand that visual appeal is not the issue.  The purely visual
appeal of the Earth-Moon photo I was talking about is pretty low too.

I've seen lots of photos of the other planets which only display a couple of
pixels.  Seeing the real Jupiter etc. with the naked eye on a clear dark night
is pretty impressive to me intellectually ("gee, that's really one of the other
planets I'm looking at, live, sitting right out there!").

The pin-point photo of the Earth is the new thing, but I can't quite get worked
up about it the way some people do.
						-- Tom

  I agree. I'd like to get my hands on a poster showing close ups of
lots of the planets and moons taken by Voyager. That would be impressive.
So far I haven't seen anything like that including Neptune.

  George

Subject: Voyager Update - 06/08/90
Message-ID: <[email protected]>
Date: 9 Jun 90 07:04:39 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                    Voyager Mission Status Report
                            June 8, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data. One frame of high-rate Plasma Wave (PWS) data was
recorded on May 19 and May 29.  High-rate Ultraviolet Spectrometer
(UVS) observations of Markarian 335 and HD 212571 were conducted on
May 25 and May 29, respectively.  In each case, there was no station
coverage to receive the data, so the 7 hours and 12 minutes of the
first observation and 7 hours and 10 minutes of the second were lost. 
 
     Also on May 29 a pre refresh checksum and memory read-out
sequence was executed on the Computer Command Subsystem (CCS) B memory
in preparation for the CCS B memory refresh.  On May 30 real-time
commands were transmitted to initiate the CCS B memory refresh and to
reset the CCS status telemetry execution of the refresh sequence, and
the status telemetry reset was performed as expected.  CCS checksum
and memory read-out verification of the refresh sequence were received. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  Nine PWS frames were played back on May 24 and better
than 99% of the data were recovered.  On May 29, one frame of
high-rate PWS data was recorded. High-rate UVS observations of
Markarian 509 were conducted on May 28 and May 30, but, due to limited
70 meter station availability, only about 19% of the total data were
acquired and that was degraded due to rain over the tracking station
in Australia. 
 
     On May 29 an Attitude and Articulation Control Subsystem (AACS)
patch was linked and verified by AACS memory read-out.  The last
Plasma Subsystem Calibration (PLSCAL) was also performed in its old
format on May 29.  The Plasma instrument responded well to the 15
calibration commands and the data quality was good. 
 
     Real-time commands to enable the Flight Data Subsystem (FDS)
transfer and perform a Computer Command Subsystem Calibration (CCSCAL)
were transmitted to the spacecraft on May 30.  All commands were
successfully received by the spacecraft and checksum verification was
received.  The CCSCAL indicated that there has been no change in the
instruction cycle timing derived from the CCS oscillator when compared
with the sequence timing derived from the FDS oscillator.  
 
                  CONSUMABLE STATUS AS OF 6/08/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    5             36.4 + 2.0          370         59
   Voyager 2   10             39.5 + 2.0          374         66
 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 06/13/90
Date: 17 Jun 90 19:03:18 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                     Voyager Mission Status Report
                            June 13, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data. One frame of high-rate Plasma Wave (PWS) data was
recorded on June 5.  On June 1 and June 5 high rate Ultraviolet
Spectrometer (UVS) observations were performed on the stars HD 212571
and HD 217675.  The observation on June 1 was not received as there
was no Deep Space Network (DSN) downlink coverage available.  The
observation on June 5 was degraded due to poor performance at the 70
meter antenna in Spain (DSS 63) which was attributed to bad weather
conditions; the Signal-to-Noise Ratio (SNR) was 1 to 2 db below
predicted values. 
 
    On June 7 a Computer Command Subsystem (CCS) A Memory refresh
sequence was executed.  Initially, pre-refresh CCS checksums and a
memory readout were executed.  Following verification of the CCS
checksums and memory readout, real-time commands were transmitted to
initiate the CCSA memory refresh, subsequent confirmation checksums
and memory read-out, and to reset the CCS status telemetry.  A CCS
Timing (CCSTIM) test was also executed which indicated that the time
offset between the Flight Data Subsystem (FDS) frame start and the CCS
timing chain in each processor has not changed since the previous
test.  Because of timing problems at the 34 meter antenna in
Goldstone, California (DSS 15), the memory refresh as well as the
verification checksums and memory readout were not received in the
downlink telemetry. Downlink telemetry was not acquired by DSS 15
until all but the last element of three transmitted to reset the CCS
status telemetry was received.  The subsequent CCS hours telemetry
indicates that all commands transmitted for the refresh sequence
appear to have been received and executed correctly. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  A high-rate UVS observation of Markarian 509 was
conducted on June 2 but, due to limited DSN station availability, only
about two-thirds of the data were acquired.  One frame of high-rate
PWS data was recorded on June 5. 
 
     On June 4 CCSLB005 began execution, and a transfer to the FDS
program was performed.  Spacecraft performance for the load start and
transfer was nominal.  A Spacecraft Time (SCT) Detailed Status Check
was performed to verify the spacecraft performance and configuration
in the new data mode. While spacecraft performance was found to be
nominal at the status check, six "S" channels indicated "no data" from
the Test and Telemetry Subsystem (TTS) processing, and one channel
indicated changing values.  Further investigation revealed that all
these channels contained correct data in the minor frame prior to TTS
processing.  Currently the problem is thought to be in the new TTS software. 
 
     On June 5 a PWS observation was recorded in the new data mode. 
This data will be played back on July 12 and July 26. 
  
                  CONSUMABLE STATUS AS OF 6/13/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    7             36.4 + 2.0          370         59
   Voyager 2    6             39.5 + 2.0          374         66
 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 06/20/90
Date: 21 Jun 90 05:06:05 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                     Voyager Mission Status Report
                            June 20, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data.  A Computer Command Subsystem (CCS) timing offset
determination test was performed on June 11 and one frame of high-rate
Plasma Wave (PWS) data was recorded on June 12.  High-rate Ultraviolet
Spectrometer (UVS) observations were conducted on HD 217675 (June 8)
and HD 199579 (June 12 and June 14). 
 
     On June 8 full Attitude and Articulation Control Subsystem
(AACS), Computer Command Subsystem (CCS), and Flight Data Subsystem
(FDS) memory readouts were executed by the Voyager 1 spacecraft.  No
problems were encountered during the readouts.  Manual comparison of
the memory readout addresses missed during the post CCSA refresh
readout on June 7 have been completed and indicate that the contents
of these addresses are as expected.  Also on June 8, a Magnetometer
Calibration (MAGCAL) was executed.  No problems were observed with the
calibration. 
 
     On June 11 a series of four Digital Tape Recoders (DTR) Tape
Positioning tests (TAPPOSs) were executed using the DTR Maintenance
(DTRMA) Block Routine (BR9).  This was the first execution of this
block routine and DTR operation was nominal.  A CCS Timing (CCSTIM)
test was also executed which indicated that the offset between the FDS
frame start and the CCS timing chain in each processor has not changed
since the previous test. 
 
     On June 8, 12, and 14 UVS observations were executed.  Spacecraft
performance appeared to be nominal, however, the downlink Signal-to-Noise 
Ratio (SNR) was 1 to 2 db below the predicted values for most of the 
three passes by the 70 meter antenna in Spain.  Only the first three 
hours of the five hour observation on June 14 was received due to the 
lack of Deep Space Network (DSN) coverage. 
 
     On June 13 real-time commands to perform a CCS Calibration
(CCSCAL) were transmitted to the spacecraft.  CCSCAL was confirmed by
CCS checksum and the CCSCAL indicated that there has been no change,
since the previous test, in the instruction cycle timing derived from
the CCS oscillator when compared with the sequence timing derived from
the FDS oscillator.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  The only significant real-time telemetry outage was
loss of one hour of CR-5T data during the June 14 70 meter antenna
tracking pass in Goldstone, California, due to on-antenna repairs to
transmitter equipment.  (These repairs delayed the planned Doppler
drift-through activities to the extent that no downlink coverage was
available to observe their effects.) 
 
     On June 11 calibrations of the Plasma Subsystem (PLS), MAG, and
Low Energy Charged Particles (LECP) instruments was performed.  This
was the first time that this autocal sequence has been executed with
the VIM-5 FDS program.  It was programmed to begin at an FDS "mod 60"
count of "9" for checkout purposes; the calibration execution appears
to have been nominal.  However, the transition from CR-5T to UV-5A
again caused problems.  The PLS and LECP status words were incorrect
and erratic.  The LECP stepping motor position was checked in the raw
data and is stepping correctly.  The engineering and temperature
channels were all nominal for the Fields & Particles (F&P) instruments
and the Cosmic Ray (CRS) and MAG instrument status words were unaffected. 
 
     UVS high-rate data were taken on PKS2155-304 starting June 14 in
the new UV-5A data mode.  The quality of this data is unknown because
lack of the capability to look at the data in near real-time. 
  
                  CONSUMABLE STATUS AS OF 6/20/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    3             36.4 + 2.0          370         59
   Voyager 2    6             39.5 + 2.0          374         66
 
       _   _____    _
      | | |  __ \  | |       Ron Baalke           |  [email protected]
      | | | |__) | | |       Jet Propulsion Lab   |  [email protected]
   ___| | |  ___/  | |___    M/S 301-355          |
  |_____/ |_|      |_____|   Pasadena, CA 91109   |

Date: 29 Jun 90 04:56:44 GMT
From: (Ron Baalke)
Subject: Voyager Update - 06/28/90
  
                     Voyager Mission Status Report
                            June 28, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data. One frame of high-rate Plasma Wave (PWS) data was
recorded on June 19. On June 15 and 18 Ultraviolet Spectrometer (UVS)
observations were performed on HD 199579 and HD 200120.  On June 15
the Signal-to-Noise Ratio (SNR) at the 70 meter antenna in Spain
varied from -0.5 to -2.1 db below the predicted value; following a
switch in masers the SNR improved significantly.  On June 18 telemetry
data from the 70 meter Goldstone antenna was severely degraded due to
a Ground Communications Facility (GCF) problem.  Telemetry was
replayed successfully the following day. 
 
     On June 18 a new sequence in the Computer Command Subsystem (CCS)
began execution and the Attitude and Articulation Control Subsystem
(AACS) Sun Sensor Heater B test was conducted.  AACS Sun Sensor Heater
B was powered on for one hour to verify it's operation; the
temperature/power profile for the heater operation was as predicted. 
 
     A pre CCSA Refresh CCS checksum was scheduled on June 21 using
the 34 meter Goldstone antenna (DSS 15).  Due to problems at DSS 15
this data was not recovered.  DSS 15 appeared to be in lock however,
Test and Telemetry Subsystem (TTS) was unable to obtain sync on the
CCS telemetry.  Real-time commands were transmitted to initiate the
CCSA refresh activity and to reset the CCS status telemetry. 
Successful completion of the refresh, which included the area of
memory in which the Command Processor and Error routines reside, was
verified by the received checksum value; the CCS status telemetry
reset was also successful. 
 
     Memory compares of the full AACS, CCS, and Flight Data Subsystem
(FDS) memory readouts performed on June 8 have been completed and
verify the memory contents are as expected.  
  
                              Voyager 2
 
     The Voyager 2 spacecraft continues to collect routine cruise
science data.  One frame of high-rate PWS data was recorded on June 19. 
 
     On June 18 the Data Capture and Staging (DACS)/TTS 2 was observed
to not be processing science data.  Following analysis, the problem
was found to be in DACS 2. 
 
     There is currently no visibility into near-real time UVS data on
Voyager 2.  The UVS investigators are looking at the new cosmic ray
data but have not yet completed their software development; they will
also be looking at the new ultraviolet data. 
 
     Several of the Low Energy Charged Particles (LECP), Plasma (PLS),
Planetary Radio Astronomy (PRA) and PWS status channels continue to be
incorrect on Voyager 2.  Other data indicate that all of the Fields,
Particles & Waves (F&P&W) instruments are on and operating normally.
Quicklook science data for the Cosmic Ray (CRS) instrument have been
formatted for the new ultraviolet format and the four channels look good.  
 
                  CONSUMABLE STATUS AS OF 6/28/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    5             36.4 + 2.0          370         59
   Voyager 2    5             39.5 + 2.0          374         66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Date: 5 Jul 90 22:52:04 GMT
From: (Ron Baalke)
Subject: Voyager Update - 07/05/90
  
                      Voyager Mission Status Report
                            July 5, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data. One frame of high-rate Plasma Wave (PWS) data was
recorded on June 26. High-rate Ultraviolet Spectrometer (UVS)
observations were conducted on HD 200120 on June 22, and on HD 206165
on June 26 and 28, and on HR 264 on June 28.  There was sufficient
Deep Space Network (DSN) coverage to capture all of the data. 
 
     On June 25 an AGC/Command test was performed over the 34 meter
antenna in Australia (DSS 42) and downlinked over the 34 meter antenna
in Goldstone, California (DSS 12). The test indicated that there has
been no apparent change in the spacecraft receiver or command
threshold since launch. 
 
     Also on June 25 the Attitude and Articulation Control Subsystem
(AACS) Sun Sensor heater B was powered on and heater A turned off; the
heater switch was made to avoid a Sun Sensor low temperature limit
violation.  Following stabilization, the Sun Sensor temperature was +4
degrees C above the predicted value. 
 
     A pre Computer Command Subsystem-B (CCSB) Refresh checksum was
downlinked from the spacecraft on June 27; real-time commands were
subsequently transmitted to initiate the CCSB refresh activity and
reset the CCS status telemetry. Successful completion of the refresh,
which included the area of memory in which the Command Processor and
Error routines reside, was verified by the received checksum value;
the CCS status telemetry reset was also successful. 
 
     A Magnetomter Calibration (MAGCAL) was conducted on June 28. 
Data quality was good.  Cruise data appeared normal for the Fields &
Particles instruments on Voyager 1. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continue to collect routine cruise
science data. On June 26, memory readouts of the AACS, CCS, and FDS
were performed and one frame of high-rate PWS data was recorded. 
 
     On June 25, in the continuing checkout of the Voyager
Interstellar Mission (VIM-5) Flight Data Subsystem (FDS) program,
two-frame AACS memory readouts were performed in two formats in the
UV5A data mode.  Spacecraft and Ground Data Subsystem (GDS)
performance were nominal.  On June 27 a real-time command file was
transmitted to patch the FDS VIM-5 program.  This patch was made to
correct an FDS software error which would have resulted in the loss of
science data.  The memory modification was verified by FDS checksum. 
 
     Full AACS, CCS, and GDS memory readouts were executed on June 26
while in the EH12 data mode.  These memory readouts were also recorded
and will be used for further checkout of the VIM-5 program, when they
are played back on July 12, in the PB 15 data mode.  Memory compare
requests were submitted for the readouts' the CCS and FDS readout
compares have been returned and indicate the memory contents are as
expected. 
 
     There is currently no visibility into near-real-time science data
on Voyager 2.  Approximately half of the investigator teams have
reported on the status of the new CR5T and UV5A data modes from their
analyses of tapes.  These reports indicate the science data
investigated so far are correctly formatted. 
 
     Several of the status channels on four of the science instruments
continue to be incorrect on Voyager 2.  
 
                  CONSUMABLE STATUS AS OF 7/05/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    6             36.4 + 2.0          370         57
   Voyager 2    7             39.5 + 2.0          374         66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |
 

Date: 12 Jul 90 21:28:51 GMT
From: (Ron Baalke)
Subject: Voyager Update - 07/12/90
  
                     Voyager Mission Status Report
                            July 12, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues its routine collection of
cruise science data.  One frame of high rate Plasma Wave (PWS) data
was recorded on 7/3.  High rate Ultraviolet Spectrometer (UVS)
observations of HR 264 and HD 19832 were conducted on June 29 and July
3 respectively.  Spacecraft and Deep Space Network (DSN) performance
was nominal for the observation. 
 
     On June 29 full Attitude and Articulation Control Subsystem
(AACS), Computer Command Subsystem (CCS), and Flight Data Subsystem
(FDS) memory readouts were executed on the spacecraft.  Memory
compares have been requested and received which indicate that the
memory contents for each subsystem memory are as expected.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues its routine collection of
cruise science data.  One frame of high rate PWS data was recorded on
July 3.  UVS observations of Feige 7 and Delta Ceti were made while in
UV-5A data mode.  The five glimpses into the data quality during the
week indicated that everything seems to be going well. 
 
     The UV-5A Planetary Radio Astronomy (PRA) and PWS data appeared
nominal. However, the status words for PRA are still incorrect even
though the software shows the correct values are present. 
  
                  CONSUMABLE STATUS AS OF 7/12/90
 
    P R O P E L L A N T    S T A T U S          P O W E R
 
                     Consumption
             One Week    Propellant Remaining     Output     Margin
  Spacecraft  (Gm)                (Kg)            Watts      Watts
 
   Voyager 1    5             36.4 + 2.0          370         55
   Voyager 2    6             39.5 + 2.0          373         66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    UPce 07/15 1246 Voyager 2 discoveries continue; lightning on Neptune
 
   IOWA CITY, Iowa (UPI) -- University of Iowa space researchers say they
have found lightning on Neptune as the result of last August's flyby of
the planet by the Voyager 2 spacecraft.

   Officials said analysis of data recorded by a plasma wave detector
placed aboard the spacecraft showed weak signals indicating the presence
of lightning.

   The discovery was made by the same team which discovered lightning on
Jupiter in 1979 during the flyby of that planet by Voyager 1.

   University of Iowa astrophysicist Donald Gurnett said the team
believed in August they had detected "whistlers" in information gathered
by Voyager 2 but waited until they could further study the data before
announcing their discovery.  A "whistler" is a radio signal which
indicates the presence of lightning.

   Gurnett said the presence of the "whistlers" probably also indicates
the presence of a convective storm system, much like a thunderstorm on
Earth.  Although Gurnett said his team is not sure of the exact source of
the signals, it may be from the planet's so-called Great Dark Spot.  That
spot is thought by most scientists to be an Earth-sized cyclone.

   Gurnett compared the radio waves, found at frequencies of 5 to 12
kilohertz, to listening to a thunderstorm.

   "You hear the thunder in your house, but if you don't see the
lightning, you don't know where it's from," he said.

   With the announcement, Neptune joins Earth, Jupiter, Saturn, and Uranus
as the only planets known to have lightning in their atmospheres.
[Venus may have lightning as well. - LK]

   The school's plasma wave detector is one of the few experiments still
being used on Voyager 2 spacecraft as it leaves the solar system.
Scientists are hoping it will help determine when the Sun no longer
"influences" the solar system.
  

       The Aug. issue of National Geographic has an excellent article
    on Voyager with some outstanding reconstructed photos of the plants
    and the solar system. This is visually exciting stuff.
    
    Dennis
    

Date: 24 Jul 90 16:12:47 GMT
From: (Ron Baalke)
Subject: Voyager Images Reveal New Saturn Moon
 
    NEW MOON DISCOVERED ORBITING PLANET SATURN
 
     A new moon orbiting planet Saturn has been discovered by Dr. Mark
Showalter, a researcher at NASA's Ames Research Center, Mountain View,
Calif.  Showalter found the small, bright object while analyzing
images taken by the Voyager 2 spacecraft. "It was very gratifying to
see it," he said.  Showalter used a computer program he wrote to sort
through 30,000 images sent back to Earth during the Voyager/Saturn
encounters in 1980-81. The Voyager images that Showalter used were
stored on CD-ROM disks which were created by the Jet Propulsion Lab in
Pasadena, California. 
 
     When the discovery is certified by the International Astronomical
Union (IAU), it will bring to 18 the number of Saturnian moons.  The
new moon has a diameter of only 12 miles and is temporarily designated
1981S13.  It orbits in the major gap, known as Encke's gap, in
Saturn's outermost major ring, the "A" ring. 
 
     Now Saturn's smallest known satellite, the moon pushes material
away from its orbit and is believed to cause the 200 mile-wide Encke's
gap.  The same "shepherding effect," Showalter said, produces Saturn's
thin, outermost "F" ring, with moons orbiting on either side of the
ring, constraining the material. 
 
     A wavy pattern in the ring material on both sides of Encke's gap
was first noticed by Ames' ring expert Dr. Jeff Cuzzi while studying
basic ring structure in the mid-1980s.  Adapting a theory from
galactic dynamics, he and Dr. Jeffrey Scargle, also at Ames, suggested
that the disturbance was caused by an unseen asteroid-sized moon in
the gap. 
 
     Showalter further analyzed the disturbance and used this "moonlet
wake" pattern, resembling a motorboat wake, to determine the position
and mass of the unseen body.  The amplitude of the waves, he said,
suggested the mass of the unobserved object and the wavelength of the
ripples revealed the moon's possible position. 
 
     Showalter's computer program combined information on the Voyager
spacecraft's position and camera direction with his prediction of the
orbit to search through the enormous stock of Voyager imagery and select 
the frames where the moon would fall in the camera's field of view. 
 
     Brian Marsden of the IAU contacted Showalter saying, "I
congratulate you on this modern-day repetition of the discovery of
Neptune.  It's a nice piece of work."  Planet Neptune also was first
predicted by theorists who observed its gravitational influence on
Uranus before sighting it in 1846. 
 
     Showalter's research is supported by the Ames Space Science
Division under a joint agreement with Stanford University.  He is a
research affiliate at the Stanford Center for Radar Astronomy. 

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

Date: 25 Jul 90 23:16:04 GMT
From: (Ron Baalke)
Subject: Voyager Update - 07/25/90
  
                     Voyager Mission Status Report
                           July 25, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues its routine collection of
cruise science data.  One frame of high-rate Plasma Wave (PWS) data
was recorded on July 17.  High-rate Ultraviolet Spectrometer (UVS)
observations of HR 1350 were conducted on July 16, 17, 18 and 19. 
Spacecraft and Deep Space Network (DSN) performance was nominal for
the activity. 
 
     On July 13 a spacecraft roll maneuver (MAGROL) sequence was
executed by the spacecraft.  The MAGROL consisted of ten 360 degree
rolls performed by the spacecraft.  The Magnetometer instrument was
calibrated while the Voyager 1 performed the MAGROL.  A playback of
the MAGROL on July 20 will allow comparison to the near real-time
data.  The Attitude and Articulation Subsystem (AACS) gyro drift rates
prior to the maneuver were pitch = 0.046 degrees/hour, yaw = 0.079
degrees/hour, and roll = 0.010 degrees/hour.  The downlink SNR during
the roll turns varied from 0 db to 1.5 db over the 70 meter and 34
meter antenna array in Spain.  Following the maneuver the AACS A and B
gyros were turned off.  Three science channels had indications of "no
data' during the GS03 data mode period. 
 
     Real-time command traffic was limited to a dummy CC on July 19. 
Due to a CPA configuration error, the command was transmitted with an
incorrect carrier suppression setting (3 dB instead of 0.54 dB). 
Nevertheless, the command was accepted by the spacecraft.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues its routine collection of
cruise science data.  UVS high-rate data were taken on HD27778 through
part of July 18 in the UV-5A data mode.  From that point through the
middle of July 19, high-rate data were taken on HD23180 and HD19832. 
The numerous glimpses into the data during the week indicated that
everything seems to be going well, however, data hits are showing up
with regularity in the UV-5A data mode. 
 
     Playback of the mini Cruise Maneuver (mini-CRSMVR) was performed
on July 17. This data had been previously played back, but some of it
was lost due to lack of DSN coverage.  One frame of high-rate PWS data
was also recorded on July 17. 
 
     A memory compare of the Flight Data Subsystem (FDS) memory
readout played back in the PB15 data mode on July 12 has been
completed and confirms the memory contents as well as the data mode
verification.  The AACS compare, of data also played back in PB 15,
has been completed and is currently being analyzed; the Computer
Command Subsystem (CCS) compare process appears to be experiencing
problems and has yet to produce any usable output.   
 
                  CONSUMABLE STATUS AS OF 7/25/90
 
         P R O P E L L A N T    S T A T U S           P O W E R
 
            Consumption
             One Week    Propellant Remaining      Output   Margin
Spacecraft     (Gm)               (Kg)             Watts    Watts
 
 Voyager 1      46            36.4 + 2.0             370      57
 Voyager 2      11            39.5 + 2.0             373      66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |
 

It amazes me that they can still get a usable signal from these
spacecraft from so far away, and with so little transmit power.
I think I read in an earlier note that the forecasted life is
still several years away, and that because of power supply
failure rather than signal strength.  Pretty incredible stuff!

Anybody know more about this?  I have a good background in
microwave and it still seems like a miracle.  Would an antenna
placed on a satellite above the atmosphere/magneosphere help with
these deep space signals?  We ought to send out a bunch of these
things.

    Re: .205
    
    A lot of what you are asking about is nested in the 200 odd replies to
    this note...  Permit me to concentrate some of it here -- and add
    a bit.
    
    
    The Deep-Space Network (DSN) went through a variety of upgrades over
    the past few years to keep up with the fading signals of the Voyager
    spacecraft (they are about 10**-16 watts, if that means anything).
    
    The most notable change was the upgrading of the 64-meter dishes in
    Spain, Australia, and California to 70-meters.  This "upgrade" really
    amounted to rebuilding them.  The size increase, coupled with some
    remarkable alignment techniques (keeping the plates of a dish in line
    to tolerances below a millimeter) improved the signal strength by 55%.
    
    To handle the large amount of telemetry that was produced at the
    Neptune encounter, other dishes were combined and arrayed - the most
    notable addition was the Very Large Array (VLA) in New Mexico (the
    VLA is a radio astronomy site consisting of 27 25-meter dishes).
    The VLA + a 70m dish can improve signal reception by a factor of 3 over
    a single 70-meter antenna.  A 64-meter antenna in Usuda Japan was also
    employed for the radio science part of the Neptune encounter.
    
    The maximum data rate at Saturn was 115,200 bits per second.  By the
    time it reached Neptune the rate had dropped to 21,600 bits/second (I
    assume it is slowing dropping still).  [Note: This is one reason why
    experiments like the Plasma Wave Subsystem (PWS) record their data.
    The PWS generates data at 115Kbits/second.  It must be recorded and
    transmitted at a lower rate for it to be used nowadays.]
    
    Voyager transmits information through a 3.7 meter High-Gain Antenna
    (HGA).  The HGA transmits data on two frequencies:
       8.4 gigahertz (X-band) - Science and engineering data
       2.3 gigahertz (S-band) - Engineering data (health)
    
    For the VIM (Voyager Interstellar Mission) phase, telemetry is
    transmitted at a much lower rate - you just can't have several football
    fields worth of antenna hanging around all the time.   If I've got my
    numbers right a minimum of 46.6 bps (presumably over the X-band
    antenna) is needed for the fields and particle science experiments.  A
    34-meter antenna can handle this rate until 2011 or so, a 70-meter
    antenna kicks that 20 the year 2037. The UVS (Ultraviolet Spectrometer)
    sends at 300 bps, and a 70-meter antenna can handle that until 2011 or
    so.  I'm not really sure why there are differences - my guess has do do
    with the intruments lowest data rate combined with the best slowdown
    possible with the tape recorder.   I assume they probably have somewhat
    better rates right now and for the next few years
    
    The current DSN capabilities are:
    
    Goldstone:
    
       DSS 12 - 34-meter, transmit/receive
       DSS 14 - 70-meter, transmit/receive
       DSS 15 - 34-meter, receive only
       All three can be arrayed to improve signal strength.
    
    Canberra (Australia - New South Wales at Tidbinbilla)
       DSS 42, DSS 43, and DSS 45 - Same as their counterparts at
       Goldstone.
    
    Madrid (Spain - Robledo actually)
       DSS 61, DSS 63, and DSS 65 - Same setup
    
    When you think of all the data we get from Voyager, remember that the
    DSN is also supporting the Pioneers 10, 11, and 12, both Voyagers,
    Magellan, Galileo.  It also maintains occasional contact with Pioneers
    6, 7, and 8, plus the International Comet Explorer.
    
    
    
    As to your final question - I would think you might have a better idea
    than I.  My (uneducated) guess is that area counts more than
    atmospheric interference, and area is cheaper to obtain here on earth.
    Interesting point though.
    
    - dave

  There was another change made to the Voyager space craft to compensate for the
lower baud rate. Voyager 1 and Voyager 2 were both launched with two computer
systems for redundancy, each of which had software to handle all functions
including navigation, house keeping, data processing (of scientific
information), and communication. 

  Once Voyager 2 was past Saturn it was decided that the software on Voyager 2
should be changed so that one computer system would handle things like
navigation and equipment control and the other would be dedicated to data
compression so that fewer bits would have to be transmitted for each picture. 

  The new software was written and tested extensively on the ground. Once JPL
felt secure with the new software, it was uploaded to Voyager 1 for further
testing. When those tests proved to be successful, the software was changed on
Voyager 2. The new software was used for both the Uranus and Neptune encounters.

  George

I think one of the problems with Earth-based receivers is that X-band (or is it
S?) signals are seriously attenuated by rain.  I seem to remember that data
has been lost due to rain at the DSN site.  

Burns

Date: 1 Aug 90 00:49:01 GMT
From: (Ron Baalke)
Subject: Voyager Update - 07/31/90
  
                     Voyager Mission Status Report
                            July 31, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues its collection of routine
cruise science data. One frame of high-rate Plasma Wave (PWS) data was
recorded on July 24 and July 31.  Data recorded during the July 13
spacecraft roll manuever (MAGROL) was played back on July 20 and,
following its completion, the X-band TWT was switched to the low-power
mode and the Bay 1 heater was turned on.  Only the last 4 turns of the
10 turn roll maneuver playback were usable, but all of the real-time
MAGROL data from July 13 are OK. 
 
     A mini-sequence that effected a number of Voyager Interstellar
Mission (VIM) related modifications to the Attitude and Articulation
Control Subsystem (AACS) and Computer Command Subsystem (CCS) software
executed nominally on July 26.  High-rate Ultraviolet Spectrometer
(UVS) observations were conducted on HR 1350 (July 20) and HD 37490
(July 24 and July 26).  Deep Space Network (DSN) performance were
nominal for the activity. 
 
     On July 25 the 34 meter tracking station in Spain brought up two
Digital Data Recorders (DDR's) for spacecraft support in an effort to
determine the cause of the timing problems recently experienced with
the High Efficiency (HEF) stations.  One of the DDR's was configured
with the ops "B" version of software and the other contained the ops
"G".  The spacecraft telemetry data Earth Receive Time (ERT) time tags
were found to have a 0.9 sec. error with the "B" software version and
no error with the "G" version; also, when the DDR running the "B" was
reinitialized during the test, the problem seemed to disappear.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  One frame of high-rate PWS data was recorded on July 24
and nine frames were played back on July 26. 
 
     An AGC/CMD Threshold test was conducted on the spacecraft by 34
meter antenna in Goldstone, California, on July 23-24.  The test
uplink appeared nominal; however, there was downlink support available
for only the first forty minutes of the three hour and fifty five
minute test.  The planned downlink station in Spain was preempted for
support of the TDF-2/DFS-2 launch. 
 
     Playback #4, containing PWS data, was executed on July 26. 
Spacecraft and DSN performance was nominal for the event.  UVS data
were taken on the sources HD19832 and NGC 5548 through July 23.  The
numerous glimpses into the data during the week indicated that
everything seems to be going well.  
 
                  CONSUMABLE STATUS AS OF 7/31/90
 
         P R O P E L L A N T    S T A T U S           P O W E R
 
            Consumption
             One Week    Propellant Remaining      Output   Margin
Spacecraft     (Gm)               (Kg)             Watts    Watts
 
 Voyager 1      9             36.4 + 2.0             370      57
 Voyager 2      11            39.5 + 2.0             373      66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |
 

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 08/09/90
Date: 15 Aug 90 16:57:42 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                   Voyager Mission Status Report
                           August 9, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data.  One frame of high-rate Plasma Wave (PWS) data was
recorded on July 31. High-rate Ultraviolet Spectrometer (UVS)
observations of BW Vulpeculae were conducted on July 27, July 30, 
and August 1. 
 
     On July 27, following the successful uplink of Voyager
Interstellar Mission (VIM) software modifications to Mini-Sequence #1
on July 26 real-time commands were transmitted to configure the Flight
Data Subsystem (FDS) data mode to EL40, reset the Computer Command
Subsystem (CCS) Status telemetry, and return the FDS mode to CR05. 
Full Attitude and Articulation Control Subsystem (AACS) and CCS memory
readouts were executed by VIM S/W Mods Mini-Sequence #1 for load
verification and memory compares were requested. The CCS Status
telemetry reset and commanded mode changes were successful.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  One frame of high-rate PWS data was recorded on July
31. Real-time commanding was performed on July 31 to adjust the
CCS/FDS timing offset.  The intent of the timing adjustment was to
establish a CCS/FDS offset between the FDS clock and COMSIM in the
year 2000.  Given the large drift rate of the Voyager 2 clock, an
offset of more than seven minutes was required.  The operational
impact of this is still being assessed but is expected to be
insignificant. 
 
    On July 27 a CCS Timing test (CCSTIM) was executed to verify the
time offset between the FDS frame start and the CCS timing chain in
each CCS processor. The test was performed as a precursor to the
FDS/CCS clock adjustment on July 31 and indicated a nominal offset. 
 
     UVS high-rate data were taken on NGC 5548 during a major portion
of this reporting period in the UV-5A data mode.  The numerous
glimpses into the data during the week indicated that everything seems
to be going well. CR-5 data were also received, but UVS has no near
real-time visibility into this data mode.  
 
                  CONSUMABLE STATUS AS OF 8/9/90
 
     P R O P E L L A N T       S T A T U S          P O W E R
            Consumption
            One Week      Propellant Remaining   Output  Margin
Spacecraft    (Gm)              (Kg)             Watts   Watts
 Voyager 1     5             36.4 + 2.0           370     57
 Voyager 2     6             39.5 + 2.0           373     66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Newsgroups: sci.space,sci.astro
Subject: Voyager Instruments Get New Instructions
Date: 21 Aug 90 05:05:55 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    From Science News -- August 18, 1990
 
    "Voyager instruments get new instructions"
 
     Flight controllers have equipped each of the two Voyager
spacecraft -- already beyond the orbits of the known planets -- with a
new computer program.  Radioed up from the Jet Propulsion Laboratory
(JPL) in Pasadena, Calif., the programs provide each craft with
operating instructions to help keep their Earthbound messages clear as
the Voyagers approach and perhaps even travel beyond the heliopause --
the yet-undetected outer boundary of the sun's vast magnetic field. 
 
     On June 4, Voyager 2 became the first to start using the new
program. Since both of its on-board computer memories are still
working, the craft was able to hold -- and check out -- the program in
one memory while retaining a simplified backup program in the other. 
Had design flaws turned up in the new instructions, this would have
allowed Voyager 2 to continue sending its data home.  No such flaws
appeared, and Voyager 1 -- which has long had only one memory in
operation -- began using the program on August 9. 
 
     The new instructions should help on-board scientific instruments
compensate for a weakening of the radio messages reaching Earth as the
Voyagers travel ever farther from home.  Electronic interference may
make signals even harder to read when and if the craft reach the far
side of the heliopause. 
 
     As messages weaken, the newly activated computer programs will
slow the release of scientific information so that the data are less
likely to be misread.  The programs have already slowed data
transmissions rate to 600 bits per second -- down from former rates of
tens of thousands of bits per second. [The Voyagers were transmitting
at 115,200 bits per second at their Jupiter encounters.] And within a
few years, the rates may drop to 160 bits per second, says Ernest J.
Franzgrote of JPL, chief of the Voyager Science Planning and
Operations Team. 
 
     The slower transmissions of data became possible in part because
controllers had already turned off three of the 10 scientific
instruments on each craft -- the camera, the photopolarimeter and the
infrared interferometer spectrometer -- as each device completed its
planned mission. Although the new instructions do not control the
camera, turning off the other two instruments allows on-board
computers to operate the remaining seven instruments more efficiently,
say Mission Director Richard P. Rudd of JPL. This permits the
computers to take on a new function: routine checking for errors in
data headed for Earth, Franzgrote says. 
 
     In addition to protecting the dimming radio signals, the new
programs have already enabled researchers in charge of each scientific
instrument to restructure the way in which it prepares data for
transmittal.  For example, by changing the timing with which
plasma-wave sensor runs through a range of wavelengths, scientists can
now eliminate the static created in its radio messages by another
instrument's motor.  The part of the program that controls the
magnetometer improves that instrument's accuracy in measuring weak
magnetic fields.  Another sensor that measures charged- particle
plasmas now runs through its full operating range four times as often
as it used to.  And the instrument measuring radio emissions from
space has become more sensitive by integrating, or building up, weak
signals for 6 seconds instead of a mere 30 milliseconds. 
 
     Engineers first began to think about protecting spacecraft
signals radioed from beyond the heliopause back in the mid-1970s,
Franzgrote says. At the time, NASA was planning a mission called
Mariner Jupiter-Saturn, known as the "grand tour" because of a rare
planetary alignment that would have allowed the probes to reach all
the way to Uranus and Neptune, and perhaps to the far side of the
heliopause.  Budget pressures nipped that project, but when the
possibility of exploring beyond the heliopause resurfaced with the
Voyager mission, NASA worked the message-protecting measures into its
plan. 

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

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 08/17/90
Date: 22 Aug 90 00:07:47 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      Voyager Mission Status Report
                            August 17, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data.  Low rate Ultraviolet Spectrometer (UVS) data was taken
on BW Vulpeculae, and Plasma Wave (PWS) data was recorded on August 6.
Also on August 6, a real-teim command file was tranmitted to load the
minimum command routine (MIN CMROT) into the Flight Data Subsystem
(FDS) memory in preparation for loading FDSL 13A3.  There were no
problems experienced with the loading of MIN CMROT. 
 
     A real-time command file was transmitted to the spacecraft on
August 7 which linked MIN CMROT.  Transmission and the subsequent
linking was successful and was verified by Computer Command Subsystem
(CCS) checksum from the CCS A processor.  During the period in which
MIN CMROT was active, only two telemetry channels were output thus
providing minimum spacecraft visibility. 
 
     On August 8, real-time commands were transmitted to the
spacecraft to perform a modification to the CCS Fault Protection
Algorithm (FPA) and to load FDSL 13A3.  The CCS FPA modification
provided FPA compatibility with the FDS 13A3 program.  Successful
loading of the uplink files was confirmed by CCS checksum (processor A
only) for the CCS FPA mod and by CCS Processor Word telemetry for FDSL
13A3; FDS checksum data is not contained in telemetry when operating
with MIN CMROT. 
 
     Real-time commands were transmitted on August 9 to link FDSL
13A3, execute a CCS Timing test (CCSTIM), and redundantly load the CCS
FPA modification.  The 13A3 load was successfully linked and verified
by the expected FDS checksum.  Loading of the CCS FPA modification was
confirmed by CCS checksum (processor A and B).  Execution of the
CCSTIM was nominal; however, as expected, the offset between the FDS
frame start and the CCS timing chain in each CCS processor was not the
nominal value due to the frame starts being moved at the linking of
MIN CMROT.  The correct time interval well be re-established with the
FDS reset and CCS clock adjustment scheduled for August 13. 
 
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  UVS were taken on sources NGC 5548, HD147933 and
HD147889. There was a PWS high-rate record frame on August 6.  Also on
August 6 the CCSL B006 began execution.  No problems were observed. 
 
     On August 7, a CCSL memory pre-refresh checksum was executed 
and indicated the memory contents were as expected.  A sequenced
modification to the DTRPRC routine was also executed.  The
modification will cause all future Digital Tape Recorder (DTR) Tape
Position (TAPPOS) executions to be performed in the low-rate rather
than the high-rate slew mode.  A CCS memory readout was also executed
following the modification to verify memory contents. 
 
     A FDS copy of the contents of primary FDS memory into secondary
memory was executed on August 7.  Following the copy execution, the
secondary memory checksum should have been identical with the current
primary checksum. This was however, not the case.  The primary checksum 
was 52A2 (hex) and the secondary was 5282.  A full FDS memory readout 
is scheduled for August 21 which will provide exact location of the 
secondary memory discrepancy. 
 
     Real-time commands were also transmitted on August 7 to initiate
a CCSA memory refresh sequence and to reset the CCS status telemetry
following the accessing of write-protected CCS memory required for the
DTRPRC modification and the CCSA memory refresh sequence.  The real-time 
commands were executed successfully; the post CCSA memory refresh checksum 
was as expected and the CCS status telemetry was reset. 
  
                  CONSUMABLE STATUS AS OF 8/17/90
 
     P R O P E L L A N T       S T A T U S          P O W E R
            Consumption
            One Week      Propellant Remaining   Output  Margin
Spacecraft    (Gm)              (Kg)             Watts   Watts
 Voyager 1     2             36.4 + 2.0           369     57
 Voyager 2     6             39.5 + 2.0           373     66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 08/24/90
Date: 24 Aug 90 23:58:02 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                      Voyager Mission Status Report
                            August 24, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continued in the engineering mode
(EL-40) while changing to the new Flight Data Subsystem (FDS) load. 
One frame of high-rate Plasma Wave (PWS) data was recorded on August 16. 
 
     Real-time command traffic was limited to August 13 and entailed
data mode commands and a FDS command to change FDS load 13A3 to 11AF
(ID only).  A FDS reset and Computer Command Subsystem (CCS) clock
adjustment (CLK ADJ) was sent that resulted in the CCS clock now
having an offset of +8 seconds.  A CCS TLM command sequence was sent
to verify the clock adjust, followed by a dummy CC and ending with a
command for "Low frequency sub-carrier" (22.5 khz vice 360 khz). 
 
     Real-time commands were transmitted to execute an FDS/CCS clock
reset and timing adjustment, perform a CCS timing (CCSTIM) test, and
configure the TMU subcarrier to the low (22.5 khz) frequency.  The
FDS/CCS clock reset performance was as predicted; the resulting offset
between the FDS spacecraft clock and COMSIM simulation was +7.376
seconds which should provide zero offset between the spacecraft and
COMSIM in the year 2000.  The CCSTIM test indicated that the time
offset between the FDS frame start and the CCS timing chain in each
CCS processor was nominal following the clock reset. Configuration of
the TMU to the low frequency subcarrier was successful.  The
spacecraft remained in this configuration until returned to the high
frequency subcarrier by sequenced command on August 16.  There was no
appreciable difference in Signal-to-Noise Ratio (SNR) or downlink
signal levels observed while in the low frequency subcarrier
configuration. Spacecraft and Deep Space Network (DSN) performance
using the TMU low frequency subcarrier is being tested because DSN
acquisition time at lower Voyager Interstellar Mission (VIM) data
rates should be improved using the low frequency subcarrier. 
 
     On August 16, full AACS/CCS/FDS memory readouts were executed;
spacecraft performance was nominal.  Many lines were missed during the
real-time processing of the readouts at the usual metering rate
requiring the rate to be reduced from 7kb to 4kb before adequate
performance was achieved; the reason for this apparent change in Data
Capture and Staging/Test and Telemetry Subsystem (DACS/TTS) performance 
is unknown.  Compares for the memory readouts have been requested. 
 
     The return of the spacecraft to a GS&E mode (CR5T) on August 16
provided an opportunity to verify the spacecraft science instrument
states ("S" channels were last observed on August 6) and to check
Ground Data System (GDS) software modifications required for VIM data
modes. All "S" channels now appear to be processed correctly in the
CR5T data mode. 
 
                              Voyager 2
 
     The Voyager 2 spacecraft continues to collect routine cruise
science data. Ultraviolet Spectrometer (UVS) data were taken on the
sources HD147889 and HD153919. 
 
     Real-time commanding was done on August 14 and consisted of CCS B
memory refresh, CCS telemetry reset, and low frequency sub-carrier
commands.  The low frequency sub-carrier commands (for both
spacecraft) are a test and both the on board sequences will revert
back to the high frequency sub-carrier within a short period.  One
hour and 11 minutes of 34 meter coverage from Australia was released
for critical Magellan activities on August 16. 
 
     On August 10, AACS Sun Sensor Heater B was turned on and off to
test its performance.  The heater performed as expected. 
 
     On August 13, there was a calibration of the Magnetometer,
Plasma, and Low Energy Charged Particles (LECP) instruments.  The
tests were successful and the instruments seem to be operating
nominally. 
 
     A pre-refresh checksum of CCSB memory was executed on August 14,
which was as predicted.  Following the checksum, real-time commands
were transmitted to initiate a CCSB memory refresh, reset the CCS
status telemetry, and configure the TMU to the low frequency
subcarrier.  The CCSB memory refresh and CCS status telemetry reset
were executed successfully; the CCSB refresh was verified by CCS
checksum.  The TMU remained configured in low frequency subcarrier for
approximately 23 minutes before returning to high frequency by
sequenced command.  There was no appreciable difference in SNR or
downlink signal levels while configured for the low frequency subcarrier.  
 
                   CONSUMABLE STATUS AS OF 8/24/90
 
           P R O P E L L A N T    S T A T U S          P O W E R

              Consumption
               One Week    Propellant Remaining     Output   Margin
Spacecraft     (Gm)               (Kg)              Watts    Watts
 Voyager 1       5            36.4 + 2.0              369      57
 Voyager 2       5            39.4 + 2.0              373      66
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 08/29/90
Date: 30 Aug 90 16:12:45 GMT
Reply-To: [email protected] (Ron Baalke)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                    Voyager Mission Status Report
                            August 29, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine cruise
science data.  One frame of recorded high rate Plasma Wave (PWS) data
on August 21.  No high-rate Ultraviolet Spectrometer (UVS) data were
taken this week, however low-rate UVS data was taken from the source
BW Vulpeculae. 
 
     On August 22 a Computer Command Subsystem (CCS) command was
transmitted to the spacecraft.  The CCS checksum received, in the
downlink, for the CCS A memory load was not as predicted by the COMSIM
simulation.  Analysis revealed that the Flight Data Subsystem (FDS)
and CCS clock reset commands transmitted and executed by the
spacecraft on August 13 were not factored into the simulation of the
CCS update; inclusion of these commands resulted in agreement between
the predicted and actual checksum received from the spacecraft. 
 
     Results of the August 16 Attitude and Articulation Control
Subsystem (AACS) and CCS memory readout compares have been received
and indicate the memory contents are as expected.  Due to an error in
the compare requests for compares of FDS memory readouts performed on
August 13 and August 16, these compares have not been completed at
this time; requests have been resubmitted for these readouts 
 
     The only significant real-time telemetry outage was loss of 2
hours and 20 minutes of Goldstone 70 meter support to the ongoing
Magellan spacecraft emergency. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  UVS data were taken on the source HD153919.  There was
a PWS high-rate record frame on August 21. 
 
     A problem was discovered on August 14.  A real-time command
(Telemetry Modulation Unit (TMU) Low Frequency Subcarrier) was
generated with a transmission time prior to completion of transmission
of the last element of the previous command (CCS Status Telemetry
Reset).  The error was caught in real time and the command rebuilt
with a delay of five minutes 
 
     On August 17 AACS gyros A and B were turned on and initialized;
the FCP swap table was also updated for their use.  This was the first
time that the Gyro On Block Routine (BR1) has been used on Voyager 2
as well as the first time this version of the routine was used.  No
problems were experienced. 
 
     On August 21 an ASCAL was performed. Execution of the maneuver
was nominal, however, a discrepancy of eighteen CCS event counts more
than predicted from the CCS B processor was noted following the ASCAL.
Upon investigation it was discovered that three AACS power codes (each
resulting in six event counts) were not included in the COMSIM simulation.  
COMSIM is expected to be modified to correct this discrepancy. 
 
     AACS, CCS, and FDS full memory readouts were also executed on
August 21 and compares of the memory contents requested.  A compare of
the contents of the FDS memory readout has been received and indicates
miscompares in the fourth bit of addresses 3934, 39A4, 39C4, and 39E4.
In all cases there is a 0 in the fourth bit rather than a 1.  A FDS
Bit Pattern Diagnostic Test (BITPAT) test is planned for August 28 to
further investigate this problem which was first observed following
the copy of the FDS program to the secondary memory on August 7. 
 
     On August 23 a real-time command file was transmitted to modify
the FDS COPY routine in the primary FDS memory so that BITPAT can be
performed. FDS checksum verification of the memory modification was
received.  A contingency AACS Gyro drift update command also scheduled
for this day was not transmitted as the gyro drifts were within
acceptable limits for the spacecraft roll maneuver (MAGROL) scheduled
for execution on August 24.   
 
                     CONSUMABLE STATUS AS OF 8/29/90
 
           P R O P E L L A N T    S T A T U S          P O W E R
              Consumption
               One Week    Propellant Remaining     Output   Margin
Spacecraft     (Gm)               (Kg)              Watts    Watts
 Voyager 1       5            36.4 + 2.0              369      57
 Voyager 2       7            39.4 + 2.0              373      52
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 09/07/90
Date: 9 Sep 90 04:13:06 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                    Voyager Mission Status Report
                          September 7, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine cruise science data.
Activities for this period included continued collection of low-rate
Ultraviolet Spectrometer (UVS) data from the source BW Vulpeculae.
There was a Plasma Wave (PWS) High-rate record frame on August 28.
 
     The only significant real-time telemetry outages was loss of one
hour and 12 minutes on August 24 to cover the front-end of the Madrid
70 meter antenna time which was taken for the Magellan emergency.
 
     On August 26 a Planetary Radio Astronomy Subsystem (PRA) Power on
Reset (POR) occurred on the spacecraft.  The configuration of the instrument
was not as expected following the post-POR configuration command.
The Flight Data Subsystem (FDS) had apparently issued the post-POR restore
command since the attenuators were removed.  The anomalous condition was
local oscillator loop unlocked vice the nominal locked state.
 
     On August 27 Computer Command Subsystem A004 (CCSL A004) began
execution.  Upon arrival for the prime shift on August 27 it was discovered
that five character printers in the real-time area were not printing due
to one cause or another; four of the printers were either not loaded
correctly or were configured in the "local" vs "online" mode and one
printer had a paper jam.  All of these printers were missing data since
early August 25.  One of the character printers that was not functioning
was the General Science printer. The hard copy was needed for analysis of
the PRA POR event.
 
     On August 27 a PRA configuration command was issued from the sequence
which should also have resulted in the PRA being configured local
oscillator loop locked.  This command did not restore local oscillator
loop lock, but it did result in the planned configuration change of
"channel toggle disable".  Investigation revealed that science data was
anomalous following the previous day's PRA POR consistent with the
configuration indicated by the PRA STAT measurement.  Analysis of the
FDS memory readout performed on August 16 indicates that the PRA
configuration command in the FDS load is correct.
 
     The Magnetometer (MAG), Low Energy Charged Particles (LECP), and Plasma
(PLS) instruments were all calibrated.  These calibrations went as
predicted. However, station problems on August 30 caused data drop-outs
and fair to average data quality return for the data.  The calibrations
should be usable. This is the first onboard calibration in the new FDS
program and the first time the Plasma instrument has been fully calibrated
since the pre-Neptune encounter period.
 
     Also on August 28 the Attitude and Articulation Control Subsystem
(AACS) B and C gyros were powered on and initialized in preparation for the
ASCAL scheduled for August 31.
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine science data.
On August 27, a slew to UVS source ALPHA VIRGINIS and a UVS calibration was
completed.  UVS data were taken on the sources HD153919, HD120324, and
11143-182.  There was a PWS High-rate record frame on August 28.
 
     On August 24 a spacecraft roll manuever (MAGROL) sequence was executed
using the Magnetometer Roll Maneuver Block Routine (MAGROL) BR3.  This was
the first use of BR3 on Voyager 2 in the CR5T data mode.  Gyros A and B were
turned off following the maneuver.
 
     On August 27 a UVS calibration (UVSCAL) sequence was executed and
real-time commands were transmitted to load the Bit Pattern (BITPAT) test
mini-sequence; successful loading of the mini-sequence was confirmed by CCS
checksum.
 
     On August 28 the BITPAT mini-sequence was executed by the spacecraft on
FDS secondary memory.  The test consisted of writing "CCCC"s and "3333"s in
FDS addresses 2000 through 3FFF and reading the memory out following each
write.  This sequence was performed three times with each pattern.  Analysis
of the test results indicates that each of the memory locations which were
previously identified to have erroneous contents on August 7 were successfully
written into and read out during the BITPAT test. Following the BITPAT test,
the FDSCPY routine was restored to its nominal configuration in FDS primary
memory and the 11AF program copied into the secondary memory.  The secondary
memory checksum was discrepant by the same amount ("32" decimal) after the
copy as it was following the August 7 copy indicating  no change in the
character of the fault since August 7.
 
     On August 29 an Automatic Gain Control (AGC/CMD) threshold test was
executed on the spacecraft; preliminary analysis indicates that the test was
performed successfully.
  
                     CONSUMABLE STATUS AS OF 9/07/90
 
           P R O P E L L A N T    S T A T U S          P O W E R

              Consumption
               One Week    Propellant Remaining     Output   Margin
Spacecraft     (Gm)               (Kg)              Watts    Watts
 Voyager 1       5            36.3 + 2.0              369      43
 Voyager 2      45            39.4 + 2.0              373      65
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 09/14/90
Date: 14 Sep 90 22:59:35 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                   Voyager Mission Status Report
                          September 14, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft continues its collection of routine
cruise science data.  Low-rate Ultraviolet Spectrometer (UVS) data was
taken on sources BW Vulpeculae and HD199579.  There was a Plasma Wave
(PWS) high-rate data recorded on September 4. 
 
     Fifty three minutes of telemetry was lost with the 34 meter
tracking station in Australia on September 2, due to rain, and fifty
one minutes on September 5, due to a receiver outage. 
 
     On August 31 a calibration of the High Gain Antenna (ASCAL) was
executed by the spacecraft; no problems were encountered.  3-way
ranging was accomplished from the 70 meter antenna in Spain to the 70
meter antenna in Goldstone. 
 
     A contingency Attitude and Articulation Control Subsystem (AACS)
Gyro Drift update command scheduled for transmission on September 5
was not uplinked as the AACS gyro drift rates were within acceptable
limits. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine cruise
science data.  UVS high-rate data were taken on 11143-182 for a major
portion of the week.  High-rate data were also taken on Markarian 509.
There was a PWS High-rate record frame on September 4.  There was also
a UVS sun monitoring event on September 6 which went well. 
 
     On August 31 the AACS Sun Sensor heater A was turned off and
heater B turned on.  Performance was nominal following the heater
switch.  On September 4 a Digital Tape Recorder (DTR) Tape Maintenance
sequence was executed. 
 
     On September 5 the AACS Sun Sensor IDET gates were updated and
the Canopus Star Tracker (CST) cone angle was configured to 4 in order
to maintain continued lock on Canopus; the AACS memory modifications
were verified by AACS memory readout. 
 
     On August 6 Playback #1, containing PWS data, was executed. 
Spacecraft and Deep Space Network (DSN) performance was nominal for
the playback. 
 
     Also on August 6 the scan platform was slewed to a position where
the UVS Sun occultation port was one degree in elevation from the Sun
and a UVS Sun Monitoring Event was executed in the UV5A data mode. 
Real-time commands were transmitted to terminate the Computer Command
Subsystem (CCS) Voyager Interstellar Mission (VIM) Protection
Sequence; confirmation was by CCS readout. Pre-Backup Mission Load
(PBBML) and several other software modifications for the AACS and CCS
plus placing the CCS "XFER TO ERROR" instruction in spare CCS memory
locations were also uplinked; confirmed by CCS checksum.  The CCS
software mods for the read-write memory were done by direct load; the
mods for write protected memory will execute from a mini-sequence on
September 11 along with readout of the appropriate AACS memory
locations.  As a result of the direct load CCS mods the Telemetry
Modulation Unit (TMU) was placed in the Low Frequency Subcarrier
configuration at the next mode change. 
 
     AACS and CCS memory compares for memory readouts performed on
August 21 have been completed and indicate the memory contents are as
expected.  
 
                     CONSUMABLE STATUS AS OF 9/14/90
 
           P R O P E L L A N T    S T A T U S          P O W E R
              Consumption
               One Week    Propellant Remaining     Output   Margin
Spacecraft     (Gm)               (Kg)              Watts    Watts
 Voyager 1       3            36.3 + 2.0              369      44
 Voyager 2       5            39.4 + 2.0              373      62
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 09/21/90
Date: 22 Sep 90 00:59:35 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                    Voyager Mission Status Report
                          September 21, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine Ultraviolet Spectromter
(UVS) data on sources HD 191610 and HD 179406.  There was a Plasma Wave
(PWS) High-rate frame recorded on September 10.
 
     On September 7 a spacecraft roll maneuver (MAGROL) was executed by the
spacecraft; following the maneuver Attitude and Articulation Control Subsystem
(AACS) B and C gyros were turned off.  The roll executed per predict and data
quality was acceptable.  The Plasma instrument was returned to its desired
configuration by the commands in the MAGROL block.
 
     On September 10 the parameter values for the AACS Sun Sensor IDET gates
were updated and AACS memory readouts performed in both the CE and MC Flight
Data Subsystem (FDS) formats for verification;  replay of the MC format
readout had to be requested as one AACS address (7220) was missed in the
real-time Test and Telemetry Subsystem (TTS) processing.  Full AACS, Computer
Command Subsystem (CCS), and FDS memory readouts were also executed and
recorded on the Digital Tape Recorder (DTR) for playback in the PB15 data
mode on September 14 to checkout this capability.  Compares of these memory
readouts have been requested.
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected UVS data on source MARK 509.  On
September 10, one frame of high-rate PWS data was recorded.
 
     The Plasma (PLS), Magnetometer (MAG), and Low Energy Charged Particles
(LECP) instruments were all calibrated on September 7, once each in the high
and low data rates.  The commands were issued per predict.
 
     On September 11 a Planetary Radio Astrononmy Subsystem (PRA) Power on
Reset (POR) occurred on the spacecraft.  Following the event, S-754 (PRA POR)
had correctly incremented from 0 to 1; S-412 (PRA STAT) indicated that the
PRA was configured in the local oscillator loop unlocked vice the nominal
locked state.  This anomalous state is the same as that experienced on
Voyager 1 following the PRA POR observed on August 26.
 
     Also on September 11 there were commanding problems which caused a forty
minute delay in the transmission of CCS Status Telemetry Reset commands and
an hour and fifteen minute delay in the transmission of a Dummy  CC.  An
"End Element Interval Failure" and a "Bit Verification Error" while using
the 70 meter antenna in Australia, caused commanding to be aborted once and
necessitated rebuilding of the CCS Status Telemetry Reset commands twice.
 
     The Pre-Backup Mission Load (PBBML) mini-sequence which made all of the
CCS software modifications to CCS write-protected memory for compatibility
with BML and long term Voyager Interstellar Mission (VIM) operations executed
nominally and the AACS readout results were per predict.
 
     On September 13 command files were transmitted to load load into CCS.
A CCS Calibration (CCSCAL) was also performed.  Checksum for all of the CCS
loads were per predict.  The CCSCAL telemetry indicated that there has been
no change in the instruction cycle timing derived from the oscillator in the
CCS when compared with the sequence timing derived from the FDS oscillator.
  
                 CONSUMABLE STATUS AS OF 9/21/90
 
      P R O P E L L A N T    S T A T U S        P O W E R

            Consumption
            One Week   Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)            Watts    Watts
 Voyager 1      35            36.3 + 2.0       369      57
 Voyager 2       6            39.4 + 2.0       370      62
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 09/26/90
Date: 27 Sep 90 15:31:17 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                    Voyager Mission Status Report
                         September 26, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine Ultraviolet
Spectrometer (UVS) data on sources HD179406, HD164794 and HD212571. 
Nine frames of Plasma Wave (PWS) data were played back September 14. 
Better than 99% of the data was successfully recovered.  There was a
PWS frame recorded on September 18. 
 
     On September 14 the Bay 1 heater was turned off and the X Band
TWT configured to the high power mode.  The Attitude and Articulation
Control Subsystem (AACS) roll/yaw deadbands were changed to 0.05/0.16
degrees and 0.16/0.05 degrees to verify performance of Attitude
Control Deadband Control (ADB) Block Routine. Playback #1, containing
memory readout data of the AACS, Computer Command Subsystem (CCS), and
the Flight Data Subsystem (FDS), and also containing the calibration
data of the Plasma Subsystem (PLS), Magnetometer (MAG), and Low Energy
Charged Particles (LECP) instruments, and Playbacks #2 and #3,
containing PWS data, were executed using PB15, PB05, and PB14 FDS data
modes respectively; spacecraft and Deep Space Network (DSN) array
performance was nominal for all the activity.  Memory readout compares
have been requested for the played back readouts. 
 
     On September 18, a Radio Frequency Subsystem (RFS) Automatic Gain
Control (AGC) Threshold test command was uplinked and received back
from the spacecraft. 
 
     Real-time commands were transmitted on September 19 to lock the
Planetary Radio Astronomy Subsystem (PRA) receiver local oscillator
loop. These commands were necessary to recover the PRA from the
incomplete Power on Reset (POR) recovery experienced on August 26. 
Instrument response to the commands was as predicted; telemetry
indicates that the local oscillator loop is locked. 
 
     Also on September 19, the Bay 1 heater was turned on and the X
Band TWT configured to the low power mode.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on source
Markarian 509. One frame of high-rate PWS data was recorded on September 18. 
 
     On September 14 AACS/CCS/FDS memory readouts were executed from
the mini-sequence uplinked on September 13.  Requests have been
submitted for compares of the memory readout data. 
 
     On September 17, Voyager 2 began processing CCS load B007 and
changed the configuration and mode on the PRA and PLS instruments.  A
PLS command was issued at the start of load B007 to put the instrument
in the desired configuration for the Voyager Interstellar Mission
(VIM).  The PRA configuration command went per predict. 
 
     On September 18 an uplink command file was transmitted to direct
load the FDS secondary memory locations which failed to load correctly
on August 7 when the FDSCPY was performed from the primary memory. 
The uplinked file also performed an FDS memory readout which verified
that the direct loading into the failed secondary memory locations was
successful.  
 
                 CONSUMABLE STATUS AS OF 9/26/90
 
      P R O P E L L A N T    S T A T U S        P O W E R

            Consumption
            One Week   Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)            Watts    Watts
 Voyager 1       6            36.3 + 2.0       369      55
 Voyager 2       5            39.4 + 2.0       370      62

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

VNS TECHNOLOGY WATCH:                           [Mike Taylor, VNS Correspondent]
=====================                           [Nashua, NH, USA               ]

                                 Voyager 2

    As Voyager 2 streaks toward its historic rendezvous with Neptune,
    technicians at the Jet Propulsion Laboratory are already looking
    ahead to the space probe's next 40 years.  For the rest of Voyager's
    life, an "expert system" computer program will assume the job of
    monitoring its flight.  Come September, the craft will be hurtling
    into deep space.  Not much will happen there, so NASA will not keep a
    mission control team at its terminals.  But Voyager 2 will continue
    to relay data of intense scientific interest.  At what distance, for
    example, will the probe slip from the last vestige of the sun's
    gravity?  To spot such milestones, the tireless computerized expert
    will keep tabs on the telemetry and will alert human operators when
    it detects anything unusual.  And if a problem crops up, the system
    will even suggest what to do about it.

        {Business Week August 28, 1990}

                             More Bugs At NASA

    Swarms of amorous wasps have decided that the tops of the launch pads 
    at the Kennedy Space Center provide the prefect conjugal bed.  NASA 
    officials claim the liaisons endanger workers and sensitive launch 
    equipment.  The inspect squad from the Agriculture Dept. has come up 
    with a solution.  Male and female wasps attract each other by releasing 
    sexually arousing scents called pheromones.  The government sting 
    operation plans to use the scent as bait this fall when the wasps
    return to Florida for their annual sojourn.

        {Business Week August 28, 1990}

<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>

        Please send subscription and backissue requests to CASEE::VNS

    Permission to copy material from this VNS is granted (per DIGITAL PP&P)
    provided that the message header for the issue and credit lines for the
    VNS correspondent and original source are retained in the copy.

<><><><><><><><>   VNS Edition : 2164     Tuesday  2-Oct-1990   <><><><><><><><>

	Re: .219

>                                               At what distance, for
>example, will the probe slip from the last vestige of the sun's gravity?

	Gee, unless they are looking for ECOs to the laws of gravity, I'm
sure glad there won't be round-the-clock technicians waiting for this signal!
I wonder if they meant to say that Voyager will be looking for the last 
detectable region of the sun's solar wind.  (The edge of the heliosphere, if
I remember the name correctly.)

								-c

Besides, wasn't the rendezvous in 1989, not 1990?

Burns

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 10/04/90
Date: 4 Oct 90 23:43:31 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                     Voyager Mission Status Report
                           October 4, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HD 212571 and HD 217657.  On September
25, one frame of high-rate PWS (Plasma Wave) data was recorded. 
 
     There was a calibration of the PLS (Plasma) instrument, the MAG
(Magnetometer), and the LECP (Low Energy Charged Particles)
instruments on September 25.  These calibrations went per predict. 
The science data from these calibrations will be sent to the
investigators on tape. 
 
     On September 26 a PRA (Planetary Radio Astronomy Subsystem) POR
(Power on Reset) occurred on the spacecraft.  Following the event, the
PRA STAT indicated that the PRA was again configured in the local
oscillator loop unlocked vice the nominal locked state.  This
occurrence was similar to the POR reported several weeks ago. 
Real-time commands are scheduled to be transmitted on October 3 to
return the PRA to its nominal state. 
 
     Compares for the AACS/CCS/FDS (Attitude and Articulation Control
Subsystem/Computer Command Subsystem/Flight Data Subsystem) memory
readouts played back in the PB15 data mode on September 14 have been
received and indicate the memory contents are as expected.  This check
was performed in the process of validating the FDS VIM-5 (Voyager
Interstellar Mission-5) FDS program.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on source
Markarian 509. There was a PWS High-rate record frame on September 25.
 
     On September 21, the TWNC was turned off. On September 22, 3-way
ranging was accomplished from the 70 meter antenna in Australia to the
34 meter antenna in Spain.  Coherent doppler gathering was not
possible because the Australia's MDA (Metric Data Assembly) was red. 
On September 25, 3-way ranging was accomplished using the same two
antennas.  Again, coherent doppler gathering was not possible because
the same MDA was still red.  On September 25 and 26, science calibrations 
for PLS/MAG/LECP were completed, and the TWNC was turned on. 
 
     There were two tracking outages over 30 minutes; on September 25,
the 34 meter antenna in Spain had a 32 minute outage going from 1-way
to 3-way, and on September 27, the same antenna had a 40 minute outage
due to low elevation and high SNR (Signal-to-Noise Ratio). 
 
     Real-time commands were transmitted on September 25 to lock the
PRA receiver local oscillator loop.  These commands were necessary to
recover the PRA from the incomplete POR recovery experienced on
September 11.  Instrument response to these commands was as predicted;
telemetry indicates that the local oscillator loop is locked.  
 
                CONSUMABLE STATUS AS OF 10/04/90
 
      P R O P E L L A N T    S T A T U S        P O W E R
            Consumption
            One Week   Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)            Watts    Watts
 Voyager 1       5            36.3 + 2.0       369      55
 Voyager 2       6            39.4 + 2.0       370      62
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

Date: 11 Oct 90 22:01:20 GMT
From: (Ron Baalke)
Subject: Voyager Update - 10/11/90
  
                        Voyager Mission Status
                           October 11, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on source  HD 217675. There was a PWS (Plasma Wave
) high-rate record frame on October 1.  On September 28, TWNC was
turned off for 3-way ranging from the 70 meter antenna in Australia to
the 70 meter antenna in Spain. On September 29 TWNC was turned back on. 
 
     There was an tracking outage of 4 hours and 55 minutes with the
34 meter antenna in Spain on September 29 because of heavy rain. 
 
     On October 3 real-time commands were transmitted to lock the PRA
(Planetary Radio Astronomy) receiver; these commands were necessary
due to the incomplete PRA recovery on September 26 which left the PRA
receiver local oscillator loop unlocked.  The PRA instrument response
to the real-time commands was as predicted. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources
Markarian 509 and PKS2155-304.  On October 2, one frame of high-rate
PWS was recorded. 
 
     There was an tracking outage of 4 hours and 45 minutes with the
34 meter antenna in Spain on September 28 because of heavy rain.  
 
                 CONSUMABLE STATUS AS OF 10/11/90
 
      P R O P E L L A N T    S T A T U S        P O W E R
            Consumption
            One Week   Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)            Watts    Watts
 Voyager 1       5          36.3 + 2.0         369      56
 Voyager 2       5          39.4 + 2.0         370      62
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |
 

From:	NAME: Betty Georgesen @IVO          
	FUNC: Sales/Software Training         
	TEL: (714) 261-4319  <GEORGESEN.BETTY AT DELREYA1 AT DOHENY AT TUS>
Date:	11-Oct-1990
Posted-date: 11-Oct-1990
Precedence: 1
Subject: WESTERN REGION EMPLOYEE TRAINING BULLETIN
To:	See Below
CC:	See Below

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

                   WESTERN REGION EMPLOYEE TRAINING BULLETIN

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

		DIGITAL VIDEO NETWORK (DVN)

		--November Schedule

    Attached to this updated schedule, you will find program content
for the 11/7 and 11/16 broadcasts. 

                         NOVEMBER BROADCAST SCHEDULE
                     -----------------------------------

    This schedule was updated on 10/8/90.  These DVN broadcasts will
be held at the Santa Clara Training Center.  You are encouraged to
reserve a seat.  Please contact Barbara Schmies @WRA or ext.6839. 
 
--------------------------------------------------------------------------------
Date   Program Name    Sponsor     Broadcast              Target
                                   Time                   Audience 
       EY Number                   (PT)       
--------------------------------------------------------------------------------

NOVEMBER
--------

11/16   Discovery       Engineering    10am - 12n           DEC Employees
        Lecture         Investment
        Series          & Review
                        Board
        
        This program will feature Dr. Edward Stone, director of the Jet
        Propulsion Laboratory, who was the chief scientist for the Voyager
        mission.  His discussion will focus around the accomplishments of
        this incredible spacecraft.

    DIGITAL VIDEO NETWORK TO BROADCAST
    "DISCOVERY LECTURE SERIES"
    NOVEMBER 16, 1990 .... 10 - 12n (PST)
    -------------------------------------

The first Discovery Lecture of the 1990-91 academic year will originate from 
the Arnold and Mabel Beckman Center of the National Academies of Sciences and 
Engineering, near the campus of the University of California at Irvine.

For Digital sites ONLY, the lecture will be rebroadcast on a taped delay 
basis to DVN and ACT centers on NOVEMBER 16, from 10-12n PST. We are pleased 
to announce that Dr. Edward Stone will deliver this Discovery Lecture.  Dr. 
Stone, director of the Jet Propulsion Laboratory, was the chief scientist for 
the Voyager mission, and will speak about the accomplishments of this 
incredible spacecraft.
 
When the Voyager lifted off the launching pad at Cape Canaveral, Florida, in 
1977, scientists and researchers never dreamed that this satellite, weighing 
less than one ton, would enable them to see new worlds, which until that 
point, appeared only as specks of light on even the most powerful telescope.

Thirteen years later, scientists still marvel at the discoveries of Voyager I 
and II that revealed a diversity of weather systems, geological evolution and 
atmospheric change never before anticipated.  And while the flight of Voyager 
is now lauded as one of NASA's most successful projects, it almost didn't get 
off the ground.  

The lecture entitled SAIL ON, VOYAGER! will include information discussed in 
The Infinite Voyage special of the same name, scheduled for broadcast on PBS 
stations, Wednesday, November 28, 1990, at 8:00 PM EST.  The Infinite Voyage 
is produced by WQED/Pittsburgh in association with the National Academy of 
Sciences.

A premier screening of The Infinite Voyage special will follow a 
question-and-answer period after the lecture.  Both The Infinite Voyage and 
the Discovery Lecture Series are funded by Digital Equipment Corporation as 
part of its commitment to education.

Associated Press Fri 19-OCT-1990 10:33                         Voyager-Triton

   NEW YORK (AP)
Giant Plumes on Neptune's Moon May Be Dust Devils Instead of Geysers

                             By LEE SIEGEL
                           AP Science Writer
   LOS ANGELES (AP) - Black plumes rising five miles above
Neptune's moon Triton may be swirling funnels called ``dust
devils'' instead of volcano-like geysers as many researchers
believe, a study published today says.
   ``The majority theory is still that they're geysers. But we're
having a lively debate,'' said planetary scientist Andrew Ingersoll
of the California Institute of Technology in Pasadena.
   At least four plumes were discovered in photographs taken by the
Voyager 2 space probe when it zoomed past Neptune and Triton in
August 1989. The plumes of nitrogen ice, nitrogen gas and carbon
dust rise five miles high, then flatten into clouds that drift 90
miles downwind.
   Because they are so tall, ``a lay person would call them
volcanoes. But the proper technical term is geysers - if that's
what they are,'' said Edward Stone, Voyager's chief scientist and
director-designate of NASA's Jet Propulsion Laboratory in Pasadena.
   In a study published today in the journal Science, Ingersoll and
Caltech graduate student Kimberly Tryka argue the plumes are
five-mile-tall dust devils, similar to those on Mars and on Earth's
windy deserts.
   ``A dust devil forms when the floor of the desert gets much
hotter than the air right above it,'' Ingersoll said Thursday.
   ``The air near the ground is very buoyant and just rises. If
there's a little breeze blowing, it can get spinning. You get this
narrow column that extends up to 2,000 feet. On Mars, they extend
up 3 1/2 miles.''
   Ingersoll said he thinks the plumes are dust devils because they
remain narrow as they rise off bare spots on Triton's icy surface.
Volcanoes and geysers usually form umbrella-shaped plumes, he said.
   A study by Laurence Soderblom and Randolph Kirk of the U.S.
Geological Survey in Flagstaff, Ariz., and Robert H. Brown of Jet
Propulsion Laboratory says nitrogen and methane ices that cover
much of Triton's surface act like a greenhouse, trapping heat from
the sun.
   They say the heat vaporizes underground ice, which then erupts
through overlying ice to form geysers.
   The debate is important for ``understanding the solar system in
which we live,'' said Roger Yelle, a planetary scientist and geyser
advocate at the University of Arizona, Tucson.
   Ingersoll said the main problem with the dust-devil theory is
that Triton's atmosphere is so thin wind shouldn't be able to whip
up dust and nitrogen ice. For dust devils to form, Triton's dust
and ice would have to be 1,000 to 10,000 times less ``sticky'' than
similar materials on Earth, Ingersoll said.
   The flight past Neptune and Triton capped an $865 million
exploration of four planets and more than 50 moons by the National
Aeronautics and Space Administration's Voyager 1 and 2 space
probes.
   The twin craft were launched in 1977. Both visited Jupiter and
Saturn. Voyager 2 went on to Uranus and Neptune. The Voyagers now
are zipping toward the edge of the solar system.
   Neptune is usually the eighth planet from the sun. But because
of Pluto's elongated orbit, Neptune now is temporarily the ninth
and outermost planet.

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 10/18/90
Date: 19 Oct 90 03:00:06 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
                         Voyager Status Report
                            October 18, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HD30614, HD217675 and HD27778.  On
October 8, one frame of high-rate PWS (Plasma Wave) was recorded. A
TLC (Tracking Loop Capacity) was uplinked over the 70 meter antenna in
Spain and completed over the 34 meter antenna in Australia.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources
PKS2155-304 and EG165.  On October 9, one frame of high-rate PWS was
recorded. Outages of 40 minutes and 1 hour 54 mintues occurred at the
34 meter antenna at Australia due to heavy rains on October 7 and 8. 
  
                 CONSUMABLE STATUS AS OF 10/18/90
 
      P R O P E L L A N T    S T A T U S        P O W E R

            Consumption
            One Week   Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)            Watts    Watts
 Voyager 1       5          36.3 + 2.0         367      55
 Voyager 2       6          39.4 + 2.0         370      61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

From: [email protected] (WILLIAM HARWOOD, UPI Science Writer)
Newsgroups: clari.tw.space,clari.news.aviation,clari.news.military
Subject: Ice geysers powered by sunlight
Date: 18 Oct 90 23:05:19 GMT
  
	Intriguing geysers on Neptune's frigid moon Triton appear to
be powered by sunlight that passes through transparent nitrogen ice on
the surface, melting subsurface material and generating towering
5-mile-high gas plumes, it was reported Thursday. 

	NASA's Voyager 2 probe sailed past Neptune and its largest
moon in August 1989 and an analysis of data collected in the close
encounter shows Triton to be one of the most bizarre bodies in the
solar system, researchers reported in 10 papers published in the
journal Science. 

	Perhaps the strangest features found to date are active
geysers that spew ice and other particles high into Triton's tenuous
nitrogen atmosphere. 

	Figuring out where the energy comes from to drive these plumes
has been a major challenge given that Triton's surface temperature
never rises beyond about 37 degrees above absolute zero -- minus 393
degrees Fahrenheit. 

	``The problem all along was trying to understand how you could
drive such phenomenon, where do you find the energy?'' said Laurence
Soderblom, who wrote two of the papers. ``What's interesting is that
now we have numerous mechanisms that have come up as possibilities.'' 

	At least four active plumes were discovered in pictures of
Triton that were radioed back to Earth by Voyager 2, including two
plumes that show up in more than one image. 

	Photographs of the plumes show what appear to be very narrow,
dark columns that rise vertically upward and then trail off to one
side as if blown by a high-altitude wind. 

	``They consist of particulate material embedded in narrow
columns of nitrogen gas, which rise to an altitude of roughly (5
miles), where the material then trails westward,'' wrote Jonathan
Lunine in an introduction to the papers. 

	All of the observed plumes were found in areas of constant
sunlight, indicating ``the mechanism by which they are generated is
associated with absorption of solar visible radiation,'' wrote Lunine,
a professor with the University of Arizona's Lunar and Planetary
Laboratory. 

	R.H. Brown and Torrance Johnson of the Jet Propulsion
Laboratory in Pasadena, Calif., and R.L. Kirk and Soderblom of the
U.S. Geological Survey in Flagstaff, Ariz., argue that sunlight
passing through transparent nitrogen ice can create a sort of
``solid-state greenhouse effect.'' 

	``The most favored one is still solar greenhousing in which
you have a solid state greenhouse made up of a layer of ice that
either overlies or has embedded in it these dark particles,''
Soderblom said in a telephone interview. ``Solar radiation is trapped
in this subsurface solid greenhouse environment.'' 

	In much the same way that sunlight passing through a car's
windows can heat up the interior on a cold day, sunlight passing
through nitrogen ice on Triton may raise temperatures below the
surface, melting the ice and producing reservoirs of gas under
pressure. 

	``It turns out you only have to raise the temperature a few
degrees, we suspect, to drive these almost explosive geysers that issue 
gas at perhaps 100 meters per second (224 mph),'' Soderblom said. 

	But calculations indicate not enough gas would be generated in
areas as small as the diameter of a plume to power the geysers as long
as the ones on Triton are believed to be active -- several Earth years. 

	Solar heating could drive nitrogen vapor sideways through a
fractured subsurface layer over a much larger area, giving rise to
long-lived plumes, Soderblom, Brown and Kirk wrote in a second paper. 

	This strange greenhouse effect, Soderblom said, ``pressurizes
the gas in a sub-surface porous reservoir, which then feeds inward
radially to a vent where it's concentrated, picks up the dark particles 
(and) launches at a velocity of about 100 meters per second.'' 

	The scientists conclude that ``lateral transport of energy by
gas flow in a porous (nitrogen) layer with a block size on the order
of (three feet) can supply the required amount of gas. The decline of
gas output ... may occur over a period comparable with the inferred
active geyser lifetime of five Earth years.'' 

	Subsurface pathways for the solar-heated nitrogen gas could be
maintained by temperature stresses that cause repeated fractures in
the ice. 

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 10/24/90
Date: 25 Oct 90 14:54:08 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                        Voyager Status Report
                          October 24, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HD 27778, DELTA CETI, and HD 1679.  On
October 15, one frame of high-rate PWS (Plasma Wave) was recorded. 
Round trip light time is 12 hours 4 minutes 14 seconds. 
 
     Maintenance work on the X/B transmitter on the 34 meter antenna
in Australia resulted in 6 hours of outage time.  Also, 3 hours and 35
minutes of tracking time was lost with the 34 meter antenna in Spain
due to rain. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on source EG
165. On October 16, one frame of high-rate PWS was recorded.  Round
trip light time is 9 hours 15 minutes 24 seconds. 
 
     On October 17 a real-time command file was transmitted to modify
the FDS (Flight Data Subsystem) PRA (Planetary Radio Astronomy
Subsystem) POR (Power on Reset) algorithm; this patch was necessary in
order for the FDS to provide the proper response to future PRA POR
occurrences and configure the PRA receiver with the local oscillator
loop locked.  The commands were verified by CCS (Computer Command
Subsystem) checksum.  The next POR will indicate if this procedure
will work properly.  
 
                 CONSUMABLE STATUS AS OF 10/24/90
 
      P R O P E L L A N T    S T A T U S        P O W E R
            Consumption
            One Week   Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)            Watts    Watts
 Voyager 1       5          36.3 + 2.0         367      55
 Voyager 2       6          39.4 + 2.0         370      61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 11/02/90
Date: 2 Nov 90 17:57:30 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         Voyager Status Report
                            November 2, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HD1679 and ANTI VGR 2.  The ANTI VGR 2
is a slew to a position pointing away from Voyager 2 to observe
background levels of interstellar hydrogen in the sky, and was
performed on October 24.  On October 19, a TLC (Tracking Loop
Capacitor test) was cancelled because the Pioneer 11 spacecraft
emergency took two hours of the Spain 70 meter antenna time originally
scheduled for Voyager 1.  The TLC was re-scheduled and completed on
October 22.  On October 23, one frame of high-rate PWS (Plasma Wave)
was recorded. 
 
     On October 22, a patch was uplinked to the FDS (Flight Data
Subsystem) to correct the PRA (Planetary Radio Astronomy Subsystem)
POR (Power-On Reset) recovery procedure.  This patch will be tested
the next time the PRA has a POR. 
 
     On October 24, science calibrations for PLS (Plasma), MAG
(Magnetometer), and LECP (Low Energy Charged Particles) instruments
was completed.  Also, the TMU (Telemetry Modulation Unit) subcarrier
was changed to high-rate. On October 25, the TMU went to low
subcarrier for execution of a PABML (Pre-Backup Mission Load)
mini-sequence, and a AACS (Attitude and Articulation Control
Subsystem) memory readout was completed.  Successful loading of the
AACS was confirmed by AACS memory readout.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources EG
165 and ANTI VGR 1.  On October 25, the scan platform was slewed to
point away from Voyager 1 to view background levels of interstellar
hydrogen (ANTI VGR 1). There was a PWS High-rate record frame on
October 23.  Also on October 23, 3-way ranging was performed from the
70 meter antenna in Australia to the 34 meter antenna in Spain. 
 
     On October 23, the MAG, LECP, and PLS instruments were
calibrated.  Only the start of this calibration was verified before
loss of DSN (Deep Space Network) station coverage. 
  
                 CONSUMABLE STATUS AS OF 11/02/90
 
      P R O P E L L A N T    S T A T U S        P O W E R
 
            Consumption
            One Week    Propellant Remaining   Output   Margin
Spacecraft     (Gm)           (Kg)             Watts    Watts
 Voyager 1       5          36.3 + 2.0          367      55
 Voyager 2       6          39.3 + 2.0          370      61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 11/09/90
Date: 10 Nov 90 00:10:52 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                        Voyager Status Report
                           November 9, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Utraviolet
Spectrometer) data on source SS CYGNI.  On October 29, one frame of
high-rate PWS (Plasma Wave) was recorded.  On November 1, there was a
slew to a position pointing toward Voyager 2 to observe interstellar
hydrogen levels between the two spacecraft. 
 
     On October 30 a DTR (Digital Tape Recorder) Maintenance sequence
was executed.  The X Band TWT (Traveling Wave Tube) was also commanded
to the high power mode and the Bay 1 heater was turned off in
preparation for Playback #4. 
 
     On October 31 Playback # 4, containing PWS data, was executed;
DSN (Deep Space Network) performance for the playback was nominal. 
Following the playback, the X Band TWT was returned to the low power
mode and Bay 1 heater turned on.  A TLC (Tracking Loop Capacitor) test
was also performed by the Goldstone 34 meter station. 
 
     On November 1, real-time commands to reset the CCS (Computer
Command Subsystem) Status Telemetry, change the FDS (Flight Data
Subsystem) data mode, load the AACS (Attitude and Articulation Control
Subsyste) and CCS Memory readout mini-sequence for execution on
November 2, load the AACS software fix (Gyro Drift Turn), Reset the
Command Loss Timer, perform a CCSTIM (CCS Timing) Test, perform a
CCSCAL (CCS Calibration) Test, and return the FDS to its original
mode, were transmitted to the spacecraft.  Many problems were
experienced while attempting to command which caused all but the first
command to be delayed, and some to be transmitted out of the planned
order.  The second element of the CCS Status Telemetry Reset command
was aborted at the first attempt and was not retransmitted as it was
redundant.  Delays from one hour and twenty five minutes to four hours
and forty seven minutes were experienced in the command file
transmission.  All transmitted commands were eventually successfully
received by the spacecraft and executed; CCS checksum verification was
received.  The CCSTIM and CCSCAL tests were executed and analysis
indicates there has been no change in the time offset between the FDS
frame start and the CCS timing chain in each CCS processor nor in the
CCS instruction cycle timing when compared with the sequence timing
derived from the FDS oscillator.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected UVS background in the
anti-Voyager 1 direction.  On November 1, the scan platform was slewed
to point towards Voyager 1 to observe interstellar hydrogen levels
between the two spacecraft. Background levels will be removed by
subtracting out the data from when the spacecraft were pointed away
from each other.  On October 30, one frame of high-rate PWS data was
recorded.  
 
            CONSUMABLE STATUS AS OF 11/9/90
 
    P R O P E L L A N T  S T A T U S  P O W E R

           Consumption
           One Week    Propellant Remaining Output Margin
Spacecraft   (Gm)           (Kg)            Watts  Watts
 Voyager 1     5        36.3 + 2.0          367      55
 Voyager 2     6        39.3 + 2.0          370      61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Triton article
Date: 14 Nov 90 03:13:12 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
    From the Science News - November 10, 1990
 
    The Mystery Behind Triton's Plumes
 
     The dark, geyser-like plumes photographed by Voyager 2 last year,
rising about 8 kilometers above Neptune's moon Triton, are far less
spectacular that the towering volcanic eruptions witnessed by Voyager 1 
on Jupiter's moon Io a decade earlier.  Yet Triton outbursts puzzle
scientists more. 
 
     Researchers had predicted Io's eruptions -- which rose hundreds
of kilometers and provided the first examples of active volcanism
seen beyond Earth.  Moreover, a now widely accepted explanation
accompanied the prediction, suggesting that a tidal tug-of-war between
Jupiter and its other Galilean moons might drive Io's volcanic fury. 
 
     Triton's plumes, by contrast, were wholly unexpected.  And the
question of what propels them high into Triton's atmosphere still
furrows many brows.  Are Triton's plumes due to some version of the
"greenhouse" effect, or to some extraterrestrial analog of the dust
devils that whirl sand across desert landscapes of Earth? 
 
     Triton's mystery plumes consist primarily of nitrogen gas that
has burst through a layer of frozen nitrogen covering Triton's
extremely cold surface.  Some Voyager researchers proposed last year
that the Sun's warming of dark particles trapped in the ice may
ultimately heat the gas underneath.  The resulting expansion of this
gas could create a pressure buildup that eventually relieves itself in
eruptions through weak spots in the ice.  It's also possible, though
less likely, that radioactive elements in Triton's core might generate
enough heat to expand and pressurize the gas, according to Laurence
Soderblom of the U.S. Geological Survey in Flagstaff, Arizona. 
 
     Whatever the source, warming the plume material by as little as 
4 degrees Celsius could "drive it out of the ground" with enough
momentum to spew it 8 km into Triton's atmosphere, says Robert. H.
Brown of NASA's Jet Propulsion Laboratory in Pasadena, California. 
And two kinds of "greenhouse" effects occurring within Triton's frozen
surface could store enough heat to power such plumes, Brown reports. 
 
     Under one possible scenario -- which he terms a "super
greenhouse" effect -- dark, absorbing matter trapped with nitrogen gas
might capture and hold heat from the Sun beneath a thin covering of
icy nitrogen.  Under a more "classical" greenhouse scenario, the Sun's
heat might merely build up throughout a pile of ice more than 60
meters deep.  Either way, the heated gas would eventually escape. 
 
     Kimberly A. Tryka and Andrew P. Ingersoll of the California
Institute of Technology in Pasadena counter that the curious plumes
might instead represent a Tritonian version of dust devils -- swirling
atmospheric vortices.  Though the mean temperature at Triton's surface
if a rigid -235 degrees Celsius, dust devils might arise if the Sun
created a relatively hot spot on Triton's surface.  The temperature
differential between that surface ice and the surrounding, colder
terrain might create enough turbulence in the nitrogen atmosphere to
drive formation of the plumes, the Caltech team concludes. 
 
     Dust devils on Earth can occur in environments well above 50
degrees Celsius, but there is evidence that they also arise in much
colder climes.  Besides Voyager's intriguing Triton images, photos
taken in the late 1970s by the Viking craft recorded 6-km-high dust
devils on Mars. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 11/16/90
Date: 16 Nov 90 17:55:26 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         VOYAGER STATUS REPORT
                           November 16, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HD 164284 and Voyager 2.  Low-rate UVS
data were taken on SS Cygni for a major portion of the week.  UVS has
no near real-time visibility into these data, so has no report on data
quality.  On November 1 there was a slew to a position pointing toward
Voyager 2 to observe interstellar hydrogen levels between the two
spacecraft.  Round trip light time between the Earth and Voyager 1 is
12 hours and 10 minutes. 
 
     There was a PWS (Plasma Wave) High-rate record frame on October 29.  
On October 31, there was a playback of PWS data.  Ten frames were
played back and better than 97.5% of the data were recovered in the
eight needed frames.  The other two frames were old data, previously
played back, used this time for lockup purposes. 
 
     On November 2, AACS (Attitude and Articulation Control Subsystem)
and CCS (Computer Command Subsystem) memory readouts were executed
from the mini-sequence loaded into the spacecraft on November 1.  The
readouts executed nominally and compares have subsequently been performed 
that indicate the AACS and CCS memory contents are as predicted. 
 
     On November 5 CCS Load A005 began execution and a TLC (Tracking Loop 
Capacitor) test was performed by the 34 meter tracking station in Spain. 
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources
Voyager 1 and F7.  UVS high-rate data were taken in the anti-Voyager 1
direction for a major portion of the week.  Glimpses into the data
indicate the instrument is doing well.  On November 1, the scan
platform was slewed to point towards Voyager 1 to observe interstellar
hydrogen levels between the two spacecraft. Background levels will be
removed by subtracting out the data from when the spacecraft were
pointed away from each other.  On November 6, one frame of high-rate
PWS data was recorded.  Round trip light time between the Earth and
Voyager 2 is 9 hours and 24 minutes. 
 
     On November 5 real-time commands were transmitted to the
spacecraft to modify the AACS "Auto Drift Stop" routine and to perform
an AACS memory readout of the changed location.  The commands were
received by the spacecraft and executed nominally; however, the AACS
readout pointer command and subsequent return to UV5A telemetry mode
command were placed too close to each other to allow for readout
completion before return to the AACS telemetry mode.  This prevented
successful verification of the AACS software modification.  
 
            CONSUMABLE STATUS AS OF 11/16/90
 
  P R O P E L L A N T  S T A T U S             P O W E R
 
           Consumption
           One Week    Propellant Remaining Output Margin
 
Spacecraft   (Gm)           (Kg)            Watts  Watts
 
 Voyager 1     5        36.3 + 2.0          367      55
 Voyager 2     6        39.3 + 2.0          370      61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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 22:27:56 GMT
Organization: Jet Propulsion Laboratory, Pasadena, CA.
 
 
                        VOYAGER STATUS REPORT
                          November 21, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data on sources HD 164284 and HD 193322.  On November 13, a frame of PWS
(Plasma Wave) data was recorded on the DTR (Digital Tape Recorder) for
future playback.
 
     On November 14, a TLC (Tracking Loop Capacitor) test was performed on the
spacecraft by the 70 meter antenna in Spain.  A science calibration for the
PLS (Plasma), MAG (Magnetometer), and LECP (Low Energy Charged Particles)
instruments was also executed on the spacecraft; however, no DSN (Deep Space
Network) station was available to receive the downlink of the calibration
sequence.
 
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on source Feige 7.
On November 13, a frame of PWS data was recorded on the DTR for future
playback.
 
     On November 14, an entire 34 meter Australia tracking pass was cancelled
due to a complex wide timing failure; the Voyager Project was not notified of
the cancellation so that arrangements could be made to modify the remaining
coverage.  This resulted in a twenty-eight hour and twenty-five minute gap in
Voyager 2 downlink coverage.  Violation of the twenty-four maximum period of
no coverage requirement could have been avoided by DSS (Deep Space Station)
rescheduling.
 
     The PLS, MAG, CRS (Cosmic Ray), and LECP instruments are measuring and
recording the heliospheric medium and looking for signs of the terminal
barrier of the heliopause.  The PLS instrument is seeing a solar wind speed
average of 450 kilometers/second with a particle density of about 0.013/cm3.
The MAG instrument is reading a magnetic field strength of about 3/4 gamma on
Voyager 2 and 1 1/3 gamma on Voyager 1.  The CRS and LECP instruments continue
to experience low background counts.
 
 
            CONSUMABLE STATUS AS OF 11/21/90
 
P R O P E L L A N T    S T A T U S           P O W E R
 
           Consumption
           One Week    Propellant Remaining Output Margin
 
Spacecraft   (Gm)            (Kg)            Watts  Watts
 
 Voyager 1     5         36.3 + 2.0           367    55
 Voyager 2     6         39.3 + 2.0           370    61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 11/30/90
Date: 11 Dec 90 03:57:34 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         VOYAGER STATUS REPORT
                           November 30, 1990
 
                              Voyager 1
 
The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data from sources HD193322 and HD206165.  On November 20 a frame of PWS
(Plasma Wave) data was recorded on the DTR (Digital Tape Recorder) for
future playback.  Round trip light time to Voyager 1 is 12 hours, 12 minutes.
  
                              Voyager 2
 
     The Voyager 2 spacecraft colleted routined UVS data from sources Feige 7
and Mark 335.  Glimpses into the data indicate the instrument is doing well.
On November 20 a frame of PWS data was recorded on the DTR for future playback.
Round trip light time to Voyager 2 is 9 hours, 28 minutes.
 
     DTR Maintenance and PMPCAL (calibration of the Plasma,
Magnetometer and Low Energy Charged Particles instruments) sequences
were executed on November 20.  Approximately two hours of the six hour
DTR Maintenance activity and thirty minutes of the three and one-half
hour PMPCAL activity wprior to the scheduled end of the Goldstone 70
meter track.  There was station coverage for only the first few
minutes of the calibration, but the limited coverage indicated the
PMPCAL was going well.  
 
           CONSUMABLE STATUS AS OF 11/30/90
 
P R O P E L L A N T    S T A T U S           P O W E R
 
          Consumption
            One Week Propellant Remaining Output Margin
Spacecraft    (Gm)            (Kg)        Watts  Watts
 
 Voyager 1     7         36.2 + 2.0        366    55
 Voyager 2     6         39.3 + 2.0        370    61
      
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 12/05/90
Date: 11 Dec 90 04:26:06 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                        VOYAGER STATUS REPORT
                          December 5, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data on sources HD 193322, HD206165, and HD217675.  On November 20 and 27, PWS
(Plasma Wave) data recorded on the DTR (Digital Tape Recorder) for future
playback.  Round trip light time is 12 hours, 14 minutes.
 
     TLC (Tracking Loop Capacitor) tests were performed on the spacecraft by
the 70 meter station in Spain on November 23 and November 27.
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources F7,
Mark 335, and 3C273.  On November 27 a frame of PWS data was recorded on the
DTR for future playback.  Round trip light time is 9 hours, 30 minutes.
 
    On November 19, TWNC was turned off so 3-way doppler could be accomplished
from the Goldstone 70 meter antenna to the 34 meter antenna in Australia.  On
November 20, one frame of high-rate PWS was recorded, DTR maintenance was
performed, science calibrations for PLS (Plasma), MAG (Magnetometer), and LECP
(Low Energy Charged Particles) instruments were completed, and 3-way was
collected at Australia and Spain.
  
               CONSUMABLE STATUS AS OF 12/05/90
 
P R O P E L L A N T    S T A T U S           P O W E R
 
          Consumption
            One Week Propellant Remaining Output Margin
Spacecraft    (Gm)            (Kg)        Watts  Watts
 
 Voyager 1     6         36.2 + 2.0        366    55
 Voyager 2     7         39.3 + 2.0        370    61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 12/13/90
Date: 13 Dec 90 22:57:28 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        VOYAGER STATUS REPORT
                          December 13, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HD206165, HD217675, and HR264.  On
December 4, one frame of high-rate PWS (Plasma Wave) data was
recorded.   On December 6, a TLC (Tracking Loop Capacitor) test was
performed from the 70 meter station in Spain, but there was no
downlink station coverage for it.  A Dummy CC command was transmitted
to the spacecraft on December 5 to reset the Command Loss Timer;
receipt of the command was verified.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on source
3C273.  UVS data were acceptable except for a short period on December
3, which was noisy. On December 4 a frame of PWS data was recorded on
the DTR (Digital Tape Recorder) for future playback.  On December 6,
the scan platform was slewed to sky position OV to search for oxygen
emissions. 
 
     On December 3 the SFOC (Space Flight Operations Center) PC
interface to the Voyager DACS (Data Capture and Staging) Reed-Soloman
decoder was installed; neither the FOT (Flight Operations Team) nor
SCT (Spacecraft Team) was informed of its installation or of the use
of it to process spacecraft data until the next day. 
  
               CONSUMABLE STATUS AS OF 12/13/90
 
    P R O P E L L A N T    S T A T U S           P O W E R
 
              Consumption
                One Week  Propellant Remaining Output Margin
    Spacecraft     (Gm)               (Kg)      Watts  Watts
     Voyager 1      5             36.2 + 2.0     366   55
     Voyager 2      7             39.3 + 2.0     370   61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 12/20/90
Date: 20 Dec 90 20:36:13 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                        VOYAGER STATUS REPORT
                          December 20, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on sources HR264 and HD22192.  On December 11, one
frame of high-rate PWS (Plasma Wave) data was recorded.  Round trip
light time is 12 hours, 15 minutes. 
 
     A total of 11 hours of tracking time outage was attributed to the
Galileo Earth Encounter. 
 
     An RFS (Radio Frequency Subsystem) TLC (Tracking Loop Capacitor)
test was executed by the 70 meter station in Spain on December 6. 
There was no visibility of the test results due to the lack of a DSN
(Deep Space Network) station to monitor the telemetry downlink. 
 
     On December 12, science calibrations for PLS (Plasma), MAG,
(Magnetometer) and LECP (Low Energy Charged Particles) instruments
were performed.  Because of insufficient DSN station coverage, the
data from the entire science calibration was lost. 
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources
SKY POS OV and NORTH GLACTIC POL.  UVS data were acceptable except for
a short period on December 8, which was noisy due to bad weather at
the station.  On December 12, the scan platform was slewed to the
North Galactic Pole as a place holder and safe position.  Round trip
light time is 9 hours, 33 minutes. 
 
     On December 10, TWNC was turned off, and 3-way doppler was
accomplished from the 70 meter antenna at Goldstone to the 34 meter
antenna at Australia. On December 11, one frame of high-rate PWS was
recorded.  On December 13, an update to the FCP swap table was done,
and Gyro's A and B were turned on in preparation for a MAGROL
(spacecraft roll maneuver) on December 20. 
 
     Real-time command traffic consisted of a dummy CC, and the CCS
(Computer Command Subsystem) load for B008, on December 10.  Because
of an operator error, and a command system "BIT VERIFY ERROR", all
commands were delayed approximately one hour.  All commands were
confirmed as per predicts.  
 
                CONSUMABLE STATUS AS OF 12/20/90
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      6             36.2 + 2.0     366   55
      Voyager 2      6             39.3 + 2.0     370   61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 01/04/91
Date: 8 Jan 91 16:30:29 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                          VOYAGER STATUS REPORT
                             January 4, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected low-rate UVS (Ultraviolet
Spectrometer) data from the source SS Cygni.  On December 18 and 25,
PWS (Plasma Wave) data was recorded on the DTR (Digital Tape Recorder)
for future playback.  Dummy CC commands were transmitted to the
spacecraft on December 19 and December 27 to reset the Command Loss
Timer; receipt of the commands were verified.  Also on December 19,
modifications to many of the spacecraft telemetry alarms were
performed where suitable for the VIM (Voyager Interstellar Mission)
cruise activity.  Round trip light time is 12 hours, 16 minutes. 
 
     A RFS (Radio Frequency Subsystem) TLC (Tracking Loop Capacitor)
test was executed by the Spain 70 meter antenna on December 13; there
was no visibility of the test results due to the lack of a DSN (Deep
Space Network) station to monitor the telemetry downlink.  The RFS TLC
test scheduled to be performed by the 34 meter Goldstone antenna on
December 21 was unsuccessful due to transmitter problems.  A
subsequent RFS TLC was performed successfully by the 70 meter
Goldstone antenna on December 27.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft took UVS high-rate data at the North
Galactic Pole and sources 3C273 and NGC4151.  Glimpses into the data
indicate the instrument is doing well. There were PWS High-rate frames
recorded on December 18 and December 25.  Round trip light time is 9
hours, 36 minutes. 
 
     On December 13 AACS (Attitude and Articulation Control Subsystem)
A and B gyros were turned on in preparation for the MAGROL (spacecraft
roll maneuver) sequence scheduled for execution on December 20.  On
December 18, a PMPCAL sequence (calibrations of the Plasma,
Magnetometer, and Low Energy Charged Particles instruments) was also
successfully executed by the spacecraft. 
 
     A Dummy CC command and a command file to perform a AACS Gyro
drift update in the yaw axis were transmitted to the spacecraft on
December 19.  These commands were delayed two hours from their planned
transmission times due to high winds at SPC 10 (Signal Processing
Center 10) which prevented their transmission over the 70 meter
Goldstone station.  A one hour non-scheduled uplink only pass over the
70 meter Australia station was acquired and the commands were
subsequently transmitted; receipt of the commands was verified by CCS
(Computer Command Subsystem) telemetry and AACS memory readout. 
 
     Also on December 19, modifications to many of the spacecraft
telemetry alarms were performed where suitable for the VIM cruise
activity. 
 
     A MAGROL sequence was executed by the spacecraft on December 20;
the AACS A and B gyros were turned off following the maneuver. 
  
                CONSUMABLE STATUS AS OF 01/04/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 Two Weeks  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      10            36.2 + 2.0     366   55
      Voyager 2      51            39.2 + 2.0     370   59
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager 1 Update - 01/06/91
Date: 8 Jan 91 16:31:55 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         VOYAGER 1 STATUS REPORT
                            January 6, 1991
 
     On January 6, the Voyager 1 spacecraft experienced a telemetry
subcarrier power fluctuation during a Goldstone 34 meter/70 meter
tracking pass.  The 34 meter station in Australia was then configured
for Voyager 1 support the same day and verified that the telemetry
subcarrier power level was indeed low, but did achieve telemetry lock
at 12:16 PM (PST).  The telemetry subcarrier power level was measured
at 0.4 volts, and the Spain tracking station measured the power level
at 0.3 volts later that evening. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 01/08/91
Date: 9 Jan 91 00:21:55 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                         VOYAGER STATUS REPORT
                            January 8, 1990
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data on sources HD22192, SS CYGNI, and HR 1350.  On December 18, one frame of
high-rate PWS (Plasma Wave) data was recorded.  Round trip light time is
12 hours, 16 minutes.
 
     On December 21, a TLC (Tracking Loop Capacitor) test was not done at with
the 34 meter Goldtone antenna due to a red transmitter.  With Project
agreement, the TLC will not be re-scheduled.  On December 25, one frame of
high-rate PWS data was recorded.  On December 27, a TLC was completed from
the 70 meter Goldstone antenna to the 34 meter Spain antenna.
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources NORTH
GALACTIC POLE, 3C273, NGC 4151, and 53 PER.  There were several short outages
in high-rate UVS data on January 2 and January 3.  All other data reviewed
looked fine.  On December 17, CCS (Computer Command Subsystem) Load B008
started, and was as per predicts.  On December 18, one frame of high-rate PWS
data was recorded, and science calibrations for the PLS/MAG/LECP
(Plasma/Magnetometer/Low Energy Charged Particles) instruments were completed
successfully.  Round trip light time is 9 hours, 36 minutes.
 
     On December 20, a MAGROLL (spacecraft roll maneuver) was executed and,
following its completion, the AB gyro pair was turned off.  This caused a
command moratorium which lasted until December 23.  Performance was nominal.
On December 25, and again on January 1, one frame of high-rate PWS data was
recorded.
 
     Real-time command traffic consisted a Dummy CC and gyro drift update
commands that were due to be transmitted over the 70 meter Goldstone antenna
on December 19.  Because Goldstone was red, both commands were successfully
transmitted two hours later from the 70 meter antenna in Australia, thanks to
a real-time agreement with Magellan.
 
     The total outage time was 8 hours, 35 minutes. The majority of the outage
time was attributed to a 2 hour outage at Goldstone because of high winds,
a 1 hour, 20 minute outage at Australia because of a real-time agreement with
Galileo, a 2 hour, 40 minute outage at Goldstone because of a red maser, and a
1 hour, 21 minute outage at Australia because of a reciever switch fault.
 
     A Dummy CC command was transmitted to the spacecraft on January 3 to
reset the Command Loss Timer and avoid entry into the CMDLOS routine.  The
spacecraft Sun-Earth-Probe (SEP) angle was less than 5 degrees during the
commanding; the command was not received by the spacecraft.  There was no
downlink station available for telemetry reception a RTLT (Round Trip Light
Time) following the command transmission therefore, any rationale for the
non-reception would be speculative.  A re-transmission of the Dummy CC is
scheduled for January 7. 
 
                CONSUMABLE STATUS AS OF 01/08/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      5             36.2 + 2.0     366   53
      Voyager 2      6             39.2 + 2.0     370   61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [email protected]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [email protected]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

    It has struck me from time to time that these "short" outages of 1-8
    hrs would be just long enough for an interstellar visitor to decide
    that either voyager was just issuing strange radio reflections, and
    wasn't really sending data on its own at all; or long enough for the 
    plasma drive vessel to shoot past, so that hours later well beyond the
    plasma spike, when Voyager's signals were detected again, there would
    be nothing to detect :-)
    
    Just a hopeful thought.
    
    						-**Ted**-
    

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 01/16/91
Date: 16 Jan 91 19:52:22 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                         VOYAGER STATUS REPORT
                            January 16, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data on source HR 1350.  On January 8 a frame of PWS (Plasma Wave) data was
recorded on the DTR (Digital Tape Recorder) for future playback.  Also on
January 8, a TLC (Tracking Loop Capacitor) test was uplinked from the 70 meter
station in Spain and completed over to the 34 meter station in Australia.
Round trip light time is 12 hours, 16 minutes.
 
     DTR Maintenance and science calibrations for the PLS/MAG/LECP
(Plasma/Magnetometer/Low Energy Charged Particles) instruments were executed
by the spacecraft on January 9.  Only the beginning and end of the DTR
maintenance were observed in spacecraft telemetry and only the first hour and
one-half of the science calibartion was observed due to the lack of available
DSN (Deep Space Network) support.
 
     A Dummy CC command was transmitted to the spacecraft on January 9 to
reset the Command Loss Timer and avoid entry into the CMDLOS routine.  It was
transmitted 20 minutes later than scheduled due to transmitter problems at the
34 meter station in Goldstone.
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS on source 53 PER.  On
January 8, one frame of high-rate UVS data was recorded.  Round trip light
time is 9 hours, 36 minutes.
 
     A Dummy CC command was transmitted to the spacecraft on January 7 using
the bracketed command procedure, 3 db command suppression and the high-power
transmitter at the 70 meter station in Australia.  There was no downlink
station available to monitor spacecraft telemetry a RTLT (Round Trip Light
Time)later; however, when telemetry was received the CCS (Computer Command
Subsystem) hours telemetry indicated three of the seven commands transmitted
were received by the spacecraft.  This special conservative DSS (Deep Space
Station) uplink configuration was used because the previous Dummy CC was not
acknowledged by the spacecraft.
 
     On January 10, the AACS (Attitude and Articulation Control Subsystem)
B and C gyroscopes were turned on to perform routine Gyro Conditioning.
Following the Gyro Fault Test 10 minutes later the AACS GYRO status indicated
gyroscopes AB rather than BC were on and other telemetry including temperature
and CCS indicated that a gyro swap occurred when the Gyro Fault Test was
enabled.  A mini-sequence is being planned to condition the C gyroscope and
investigate the cause of the switch and to determine why the automated fault
test failed. 
 
                CONSUMABLE STATUS AS OF 01/16/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      5             36.2 + 2.0     366   53
      Voyager 2      5             39.2 + 2.0     370   47
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager Update - 01/23/91
Date: 23 Jan 91 21:23:40 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                         VOYAGER STATUS REPORT
                            January 23, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectromter) data on sources HR 1350, HD 52089 and HD 58978.  On
January 15, a frame of PWS (Plasma Wave) data was recorded on the DTR
(Digital Tape Recorder) for future playback.  Round trip light time is
12 hours, 15 minutes. 
 
     On January 15, shortly after a slew, the IRIS (Infrared
Interferometer Spectrometer and Radiometer) Primary Heater went into
alarm due to heater output dropping below the limits.  It is currently
suspected that heater output dropped due to solar heating caused by
the pointing after the slew to HD 52089.  A second slew on January 17
did not move the scan platform a large amount but the heater output
did change a little.  The alarm limit for this heater was lowered
temporarily and will probably be restored if data after the next slew
to the South Galactic Pole on January 24 warrants it.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources 53
PER and AKN 120.  On January 15, one frame of high-rate PWS data was
recorded. Round trip light time is 9 hours, 37 minutes. 
 
     Also on January 15, science calibrations for PLS/MAG/LECP
(Plasma/Magnetometer/Low Energy Charged Particles) instruments were
completed. On January 16, another PLS/MAG/LECP science calibration was
completed.  Both sets of calibrations were as per predicts.  On
January 17, the AACS (Attitude and Articulation Control Subsystem) A &
B gyroscopes were turned off thereby completing the GYRO Conditioning.
A mini-sequence to investigate cause of the unexpected gyro swap on
January 10 is planned to be transmitted to the spacecraft on January 28. 
  
                CONSUMABLE STATUS AS OF 01/23/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      6             36.2 + 2.0     366   55
      Voyager 2      5             39.2 + 2.0     370   61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      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: Voyager CD-ROMs
Date: 28 Jan 91 05:57:22 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
     I've received a number of inquiries about the Voyager images
available on CD-ROMs.  There are eight CD-ROMs that contain about
16,000 images taken by Voyager 1 and Voyager 2 on their encounters
with Jupiter, Saturn and Uranus.  The CD-ROMs are available to the
general public at the NSSDC (National Space Science Data Center) at
the Goddard Space Flight Center. There is a charge of about $75 for
the 8 CD-ROM set, and NASA employees get a discount.  You can contact
the NSSDC at: 
 
        National Space Science Data Center
        Request Coordination Office
        Goddard Space Flight Center
        Code 633
        Greenbelt, MD  20771
 
        Telephone: (301) 286-6695
 
        Email address:   [email protected]
 
     The images are stored in compressed format on the CD-ROM with
each image being about 220K.  A decompression program, called PCDCOMP,
and an image display program that runs on an IBM PC computer, call
IMDISP, are included with the CD-ROMs.  The most recent versions of
the PCDCOMP (version 2.0) and IMDISP (version 5.6) programs can also
be obtained via anonymous ftp at ames.arc.nasa.gov site under the
filename imdisp56.zip in the pub/SPACE/IMDISP directory.  When the
images are uncompressed, they will be about 670K in size, so a large
hard disk is recommended.  For each compressed image there is a
corresponding "browse" image, which is a scaled down version of the
original image (1/16 size) which can be viewed directly off the
CD-ROM. All of the images are the raw, unprocessed images taken by the
Voyager spacecraft.  All of the images are monochrome images since
Voyager carried a black-and-white camera.  All of the color images
you've might of seen on the news and in magazines were images created
by the Image Processing Lab at JPL; there are no color images on the
CD-ROMs.  However, the IMDISP program mentioned before gives you the
capability to perform some image processing functions on the images,
as well as applying color palettes to the images. 
 
     A set of four CD-ROMs containing the Neptune images taken by
Voyager 2 is due to be released at the end of February 1991, and these
CD-ROMs will also be available at NSSDC. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | 
  ___| | | | |__) |/  | | |___   M/S 301-355        | It's 10PM, do you know
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | where your spacecraft is?
 |_____|/  |_|/       |_____|/                      | We do!

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 01/30/91
Date: 31 Jan 91 01:17:22 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                         VOYAGER STATUS REPORT
                           January 30, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data throughout this period on sources HD 58978 and the
South Galactic Pole. On January 22, one frame of high-rate PWS (Plasma
Wave) data was recorded. On January 19 an TLC (Tracking Loop
Capacitor) test was scheduled over the 70 meter Canberra station;
however it was not performed due to a power outage at SPC 40 (Signal
Processing Center 40).  A TLC test was successfully performed by the
34 meter Goldstone antenna on January 24.  A Dummy CC command was
transmitted to the spacecraft on January 24 to reset the Command Loss
Timer. Round trip light time is 12 hours, 15 minutes. 
 
     On January 24, the AACS (Attitude and Articulation Control
Subsystem) scan platform was slewed to a position of azimuth 249.48
degrees elevation 57.14 degrees; the IRIS (Infrared Interferometer
Spectrometer and Radiometer) channels all returned to their nominal
values as observed prior to slewing to the low cone angle platform
position on January 16. 
 
     Also on January 24, shortly after the slew to the South Galactic
Pole, the IRIS Primary Heater went back to within 1 DN of its
pre-alarm state.  This would tend to confirm the suspicion that the
heater output dropped due to solar heating caused by the pointing
after the initial UVS slew.  The alarm limit for this heater was
lowered and will probably be left at its new value.  
 
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources
AKN 120 and HD 17925.  On January 22, one frame of high-rate PWS data
was recorded. January 24 marked the fifth anniversary of Voyager 2's
encounter with Uranus. Round trip light time is 9 hours, 37 minutes. 
 
     On January 21, the FDS (Flight Data Subsystem) commutator was
modified from the on board sequence to increase the sampling rate of
the azimuth actuator temperature.  A Dummy CC command was transmitted
to the spacecraft on January 24 to reset the Command Loss Timer.  The
bracketed command procedure and 3 db command suppression were used for
the uplink; two of the seven commands transmitted to the spacecraft
were received.  
 
                CONSUMABLE STATUS AS OF 01/30/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      5             36.2 + 2.0     366   55
      Voyager 2      6             39.2 + 2.0     370   61
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | 
  ___| | | | |__) |/  | | |___   M/S 301-355        | It's 10PM, do you know
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | where your spacecraft is?
 |_____|/  |_|/       |_____|/                      | We do!

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 02/08/91
Date: 8 Feb 91 21:38:17 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA.
  
                          VOYAGER STATUS REPORT
                             February 8, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data on the South Galactic Pole.  On January 29, one frame of high-rate PWS
(Plasma Wave) data was recorded.  Also on January 29, a TLC (Tracking Loop
Capacitor) test was executed by 70 meter Madrid antenna.  Round trip light
time is 12 hours, 14 minutes.
 
     A Dummy CC command was transmitted to the spacecraft on January 31 to
reset the Command Loss Timer.  CCS (Computer Command Subsystem) Load A006 was
also successfully transmitted to the spacecraft and verified by CCS checksum.
It is scheduled to begin on February 4.
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on source HD 17925.
On January 29 a frame of PWS data was recorded on the DTR (Digital Tape
Recorder) for future playback.  Round trip light time is 9 hours, 37 minutes.
 
     A Dummy CC command was transmitted to the spacecraft on January 28 to
reset the Command Loss Timer.
 
     Execution of the Gyroscope C investigation mini-sequence began on
January 31.  A full AACS (Attitude and Articulation Control Subsystem) memory
readout was performed, FDS (Flight Data Subsystem) commutator changes were
made to improve visibility of AACS parameters, AACS gyro test patches were
loaded, gyro C test #1 was linked, a full AACS memory readout was executed to
verify the changes, and gyros B and C were turned on and initialized.  Gyros
B and C drift rates will continue to be monitored until the end of test #1
on February 7.  All indications were normal.
 
     The PLS (Plasma), MAG (Magnetometer), CRS (Cosmic Ray), and LECP (Low
Energy Charged Particles) instruments are measuring and recording the
heliospheric medium and continuing to look for signs of the interaction
between the solar wind and the interstellar medium.  On January 25, the
Plasma instrument recorded a solar wind speed average of 385 kilometers/second,
with a particle density of about 0.024/cc.  The Magnetometer instrument is
reading a magnetic field strength before background subtraction of about 0.7
gamma on Voyager 2 and 1.3 gamma on Voyager 1.  The Cosmic Ray and Low Energy
Charged Particle instruments continue to measure energetic electrons and
nucleons.
  
                CONSUMABLE STATUS AS OF 02/08/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      6             36.2 + 2.0     366   53
      Voyager 2      6             39.1 + 2.0     370   46
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | 
  ___| | | | |__) |/  | | |___   M/S 301-355        | It's 10PM, do you know
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | where your spacecraft is?
 |_____|/  |_|/       |_____|/                      | We do!

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 02/13/91
Date: 13 Feb 91 18:09:05 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                         VOYAGER STATUS REPORT
                           February 13, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet
Spectrometer) data on the South Galactic Pole and Coal Sack.  A frame
of PWS (Plasma Wave) data was also recorded on the DTR (Digital Tape
Recorder) for future playback.  Round trip light time is 12 hours, 14
minutes. 
 
     February 14 marked the one year anniversary of the taking of the
"family portrait" images of the solar system by Voyager 1. 
 
     A total tracking time outage of almost 7 hours was attributed to
the Goldstone 70 meter station being down for the past month. 
 
     On February 1, the AACS (Attitude and Articulation Control
Subsystem) A and B gyroscopes were turned on and initialized in
preparation for the MAGROL (spacecraft roll maneuver) scheduled for
execution on February 8. 
 
     On February 5, the FDS (Flight Data Subsystem) commutator was
modified from the on board sequence to increase the sampling rate of
the azimuth actuator temperature.  An AGCCMD (Automatic Gain Control
Command Threshold) Test was also conducted.  The test revealed no
apparent change in spacecraft receiver or command threshold since
launch. 
 
     On February 6, a PMPCAL (calibrations of the Plasma, Magnetometer
and Low Energy Charged Particles instruments) was executed by the
spacecraft; a Dummy CC command was also transmitted to the spacecraft
to reset the Command Loss Timer.  The contingency real-time command
for gyro drift compensation update was not needed. 
 
     Also on February 6, the scheduled RFSTLC (Radio Frequency
Subsystem Tracking Loop Capacitor) test was delayed three hours due to
a procedural error at the 34 meter Canberra station which caused the
first attempt to be aborted.  The test was successful on the second
attempt.  

                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources HD
17925 and a sky background point.  Glimpses into the data indicate the
instrument is doing well although there were several periods of
unexplained poor quality data.  There was a PWS high-rate record frame
on February 5, and DTR maintenance was accomplished.  Round trip light
time is 9 hours, 36 minutes. 
 
     On February 1, 4 and 6, the AACS B and C gyros were initialized
as part of the continuing AACS gyro C test mini-sequence.  A Dummy CC
command was transmitted to the spacecraft on February 6 to reset the
Command Loss Timer. 
 
     On February 7, the gyro C test #1 was delinked, FDS commutator
changes were made to support gyro C test #2, gyro C test #2 was
executed and the gyro fault test was enabled.  The B and C gyros
indicated no abnormal behavior during the test.  
 
                CONSUMABLE STATUS AS OF 02/13/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)               (Kg)      Watts  Watts
      Voyager 1      5             36.2 + 2.0     366   41
      Voyager 2      6             39.1 + 2.0     370   46
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | Is it mind over matter,
  ___| | | | |__) |/  | | |___   M/S 301-355        | or matter over mind?
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | Never mind.
 |_____|/  |_|/       |_____|/                      | It doesn't matter.

    Has anyone any idea how much data these spacecraft have sent back ?
    
    Chris

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 02/27/91
Date: 27 Feb 91 19:25:03 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                         VOYAGER STATUS REPORT
                           February 27, 1991
 
                              Voyager 1
 
     The Voyager 1 spacecraft collected routine UVS (Ultraviolet Spectrometer)
data on source NGC 6752.  One frame of PWS (Plasma Wave) data was recorded on
February 19.  Round trip light time is 12 hours, 13 minutes.
 
     On February 18, gyroscopes B & C were turned on for scheduled
conditioning.  Both gyros were turned on and initialized, and the gyro fault
test was enabled.  On February 14 & 20, TLC (Tracking Loop Capacitor) tests
were completed and were nominal.
 
     On February 20, a dummy CC command was transmitted to the spacecraft to
reset the Command Loss Timer; the command was received by the spacecraft.
  
                              Voyager 2
 
     The Voyager 2 spacecraft collected routine UVS data on sources ABELL 85
and FAIRALL 9.  On February 19, One frame of high-rate PWS data was recorded on
the DTR (Digital Tape Recorder).  Round trip light time is 9 hours, 35 minutes.
 
     On February 19, a dummy CC command was transmitted to the spacecraft to
reset the Command Loss Timer; the command was received by the spacecraft.
The gyro test mini-sequence was also transmitted to the spacecraft on that day;
the CCS (Computer Command Subsystem) checksum was per predicts.
 
     An AACS (Attitude and Articulation Control Subsystem) MRO (Memory Read
Out) executed out of the mini-sequence on February 21; the readout was per
predict.  Also on February 21, the B and C gyros were turned on, initialized,
and the gyro fault test was enabled.  The enable was in the same manner as
on January 10 when the gyro swap occurred; no gyro swap occurred this time.
 
     The PLS (Plasma), MAG (Magnetometer), CRS (Cosmic Ray), and LECP (Low
Energy Charged Particles) instruments are measuring and recording the
heliospheric medium and continue looking for possible signs of the interaction
between the solar wind and the interstellar medium.  On February 19, the PLS
instrument recorded an average solar wind speed of 359 kilometers/second, and
measured a particle density of about 0.011 per cc.  The Magnetometer instrument
on Voyager 2 is reading 0.7 gamma for the magnetic field strength and on
Voyager 1 a field strength of an average of around 1.3 gamma, both before
background subtraction.  The CRS and the LECP instruments continue to measure
energetic electrons and nucleons. 
 
                CONSUMABLE STATUS AS OF 02/27/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)             (Kg)        Watts  Watts
      Voyager 1       7          36.2 + 2.0       366   39
      Voyager 2       7          39.1 + 2.0       370   47
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | Is it mind over matter,
  ___| | | | |__) |/  | | |___   M/S 301-355        | or matter over mind?
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | Never mind.
 |_____|/  |_|/       |_____|/                      | It doesn't matter.

Date: 9 Mar 91 00:54:30 GMT
From: [email protected]  
      (Ron Baalke)
Subject: Voyager Update - 03/06/91
  
                          VOYAGER STATUS REPORT
                             March 6, 1991
 
                               Voyager 1
 
     The Voyager 1 spacecraft continues to collect routine science and
engineering data.  UVS (Ultraviolet Spectrometer) data was collected
from sources NGC 6752 and NGC 6681.  One frame of PWS (Plasma Wave)
data was recorded on the DTR (Digital Tape Recorder)on February 26. 
Round trip light time is 12 hours, 13 minutes. 
 
     On February 25, gyroscopes B & C were turned off.  The PWS
instrument has been observing gyro interference signals since February
18.  These interference signals ceased when the gyros were turned off.
 This completed the one week gyro conditioning. 
 
     On February 26, a short form TLC (Tracking Loop Capacitor) test
was performed; the results were nominal. 
 
                               Voyager 2
 
     The Voyager 2 spacecraft also continues to collect routine
science and engineering data.  UVS data was collected from source
FAIRALL 9.  On February 26, one frame of high-rate PWS data was
recorded.  Round trip light time is 9 hours, 34 minutes. 
 
     On February 22, an AACS (Attitude and Articulation Control
Subsystem) MRO (Memory ReadOut) was performed; the results were per
predicts.  Gyroscopes B and C were also turned off.  This completed
the second gyro swap investigation mini-sequence. 
 
     On February 28, a science calibration for PLS/MAG/LECP (Plasma/
Magnetometer/Low Energy Charged Particles) instruments was completed. 
Initial analysis of the data indicates a successful calibration. 
 
     CCS (Computer Command Subsystem) load B009 was uplinked to the
spacecraft on February 28. The load is due to start on March 4.  
 
                CONSUMABLE STATUS AS OF 03/06/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
 
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)             (Kg)        Watts  Watts
      Voyager 1       6          36.2 + 2.0       366   55
      Voyager 2       5          39.1 + 2.0       370   59
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | Is it mind over matter,
  ___| | | | |__) |/  | | |___   M/S 301-355        | or matter over mind?
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | Never mind.
 |_____|/  |_|/       |_____|/                      | It doesn't matter.
 

From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Voyager Update - 03/21/91
Date: 22 Mar 91 07:28:01 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory, Pasadena, CA. 
 
                           VOYAGER STATUS REPORT
                              March 21, 1991
 
                                Voyager 1
 
     The Voyager 1 spacecraft collected routine science and
engineering data during the past week.  UVS (Ultraviolet Spectrometer)
data was collected from sources WD 1629+782 and SS Cygni.  On March
12, one frame of high-rate PWS (Plasma Wave) data was recorded. 
 
     On March 13, a Dummy CC was transmitted to the spacecraft to
reset the Command Loss Timer; the command was received by the
spacecraft.  Also on March 13, the Voyager Project requested that the
DSN (Deep Space Network) terminate the 34 meter Canberra track (4
hours 50 minutes) early for an arrayed antenna emergency support for
Voyager 2.  A TLC (Tracking Loop Capacitor) test was performed on
March 14; the results were nominal. 
 
     The Magnetometer instrument on Voyager 2 is reading 0.7 gamma for
the magnetic field strength, and on Voyager 1 the magnetometer instrument 
is reading an average of around 1.3 gamma before background subtraction. 
  
                               Voyager 2
 
     The Voyager 2 spacecraft also collected routine science and
engineering data. UVS data were taken on CH Cygni and BD+28 4211. 
Glimpses into the data indicate the instrument is doing well although
there were several periods of poor quality data on March 8, 10, and 13. 
 
     On March 12, a science calibration for the PLS/MAG/LECP
(Plasma/Magnetometer/Low Energy Charged Particles) instruments was
completed along with one frame of high-rate PWS being recorded. 
 
     On March 13, a quarterly playback of PWS data was scheduled.  DSS
43 (Deep Space Station 43, 34 meter antenna in Canberra) was unable to
support due to a red power supply for the line driver frequency
oscillator.  The bay 1 heater was turned off and the X band went to
high power in preparation of going to playback (7.2K).  In an attempt
to acquire the signal an array was made with both 34 meter antennas in
Canberra.  The antenna array was brought on line, but the array output
was insufficient.  The playback was not received and will have to be
rescheduled at a later time. 
 
     On March 14, gyroscopes B and C were turned on and the gyro fault
test was enabled.  No gyro swap occurred.  PWS observed unusually
strong interference signals at the turn on of the gyroscopes.  Also on
March 14, the Plasma instrument on Voyager 2 recorded the average
solar wind speed of 351 kps, a velocity average of 394 kps and
measured a particle density of about 0.015 per cm3.  
 
                CONSUMABLE STATUS AS OF 03/21/91
 
     P R O P E L L A N T    S T A T U S           P O W E R
               Consumption
                 One Week  Propellant Remaining Output Margin
     Spacecraft     (Gm)             (Kg)        Watts  Watts
      Voyager 1       6          36.2 + 2.0       366   55
      Voyager 2       6          39.1 + 2.0       369   47
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |      Jet Propulsion Lab | 
  ___| | | | |__) |/  | | |___   M/S 301-355        | Change is constant. 
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 | 
 |_____|/  |_|/       |_____|/                      | 

From: [email protected] (baalke, ron)
Newsgroups: sci.space,sci.astro
Subject: Voyager CD-ROMs On-Line
Date: 8 Apr 91 05:58:36 GMT
Sender: [email protected]
Organization: Jet Propulsion Laboratory 
 
     Peter Yee and I are pleased to announce a major addition to the
SPACE archive at NASA Ames Research Center. 
 
     There are eight CD-ROMs that contain about 16,000 images taken by
Voyager 1 and Voyager 2 on their encounters with Jupiter, Saturn and
Uranus.  Images from these Voyager CD-ROMs are now available on-line at
the Ames SPACE archives.  A CD-ROM drive has been installed at the
Ames site allowing direct access to the CD-ROM via anonymous ftp to
ames.arc.nasa.gov (128.102.18.3). The images are in the
/pub/SPACE/CDROM directory.  The plan is to rotate the CD-ROMs on a
weekly basis.  The first CD-ROM currently on-line is the Voyager
Saturn Encounter, Volume 4.  A new Magellan CD-ROM and three new
Neptune CD-ROMs are also available, and will be quickly be placed
on-line when Peter receives them. 
 
     The Voyager images are stored in compressed format on the CD-ROM
with each compressed image being about 220K.  Source code for the
decompression program, decomp.c, is available on the CD-ROM.  When the
images are uncompressed, they will be about 670K in size, so a large
hard disk is recommended.  An IBM PC version of the decompression
program, PCDCOMP, and an image display program that also runs on an
IBM PC computer, IMDISP, are also stored at the Ames site. The most
recent versions of the PCDCOMP (version 2.0) and IMDISP (version 5.6)
programs can obtained from pub/SPACE/SOFTWARE directory under the
filename imdisp56.zip. 
 
     The CD-ROMs are also available to the general public from the
NSSDC (National Space Science Data Center) at the Goddard Space Flight
Center. You can contact the NSSDC at: 
 
        National Space Science Data Center
        Request Coordination Office
        Goddard Space Flight Center
        Code 633
        Greenbelt, MD  20771
 
        Telephone: (301) 286-6695
 
        Email address:   [email protected]
  
We would like to thank the following people and organizations:
 
Dr. Bradford A. Smith, Team Leader, Voyager Project
Planetary Data System, Jet Propulsion Laboratory
National Space Science Data Center, Goodard Space Flight Center
Randall Robinson, NASA Ames Research Center Communications Operations Branch
------------------------------------------------------------------------------
 
      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
     | | | |  __ \ /| | | |     Jet Propulsion Lab |
  ___| | | | |__) |/  | | |__   M/S 301-355        | Change is constant.
 /___| | | |  ___/    | |/__ /| Pasadena, CA 91109 |
 |_____|/  |_|/       |_____|/                     |

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                       October 23, 1991

Mary A. Hardin
Jet Propulsion Laboratory, Pasadena, Calif.

RELEASE:  91-174

     More than 2 years after Voyager 2 looked Neptune's Great Dark
Spot in the eye and darted past the frozen surface of its moon
Triton, both Voyager spacecraft are continuing to return data about
interplanetary space and some of our stellar neighbors near the edges
of the Milky Way.

      After the Voyager spacecraft flew by the four giant outer
planets -- Jupiter, Saturn, Uranus and Neptune -- their mission might
have been over.  But, in fact, these 14-year-old twins are just
beginning a new phase of their journey, called the Voyager
Interstellar Mission (VIM).

     As the Voyagers cruise gracefully in the solar wind, their
fields, particles and waves instruments are studying the space around
them while searching for the elusive outer edge of our solar system -
- the heliopause.

     The heliopause is the outermost boundary of the solar wind,
where the interstellar medium restricts the outward flow of the solar
wind and confines it within a magnetic bubble called the heliosphere.
The solar wind is made up of electrically charged atomic particles,
composed primarily of ionized hydrogen, that stream outward from the
Sun.

     "The termination shock is the first signal that we are
approaching the heliopause.  It's the area where the solar wind
starts slowing down,"  said Voyager Project Scientist and JPL
Director Dr. Edward C. Stone.  Mission scientists now anticipate that
the spacecraft may cross the termination shock by the end of the
century.

     Exactly where the heliopause is remains a mystery.  It has long
been thought to be some 7 to 14 billion miles from the Sun.  Any
speculation about where the heliopause is or what it is like has come
only from computer models and theories.  "Voyager 1 is likely to
return the first direct evidence from the heliopause and what lies
beyond it," Stone said.

     As the Voyagers near the interstellar boundary, they have become
space-based ultra-violet observatories.  Their unique location in the
universe gives astronomers the best vantage point they have ever had
for looking at celestial objects that emit ultraviolet radiation.

     Both spacecraft are involved in an extensive program of
ultraviolet astronomy that allows them to study active galaxies,
quasars and white dwarf stars in ways unlike any other spacecraft or
telescope in existence.

     "Voyager's instruments allow it to observe things at wavelengths
that are for the most part unavailable to other spacecraft," said Dr.
Jay Holberg, a member of Voyager's ultraviolet subsystem team.  "The
light that Voyager is sensitive to has to be observed in outer
space."  Voyager's ultraviolet spectrometers are the only way
scientists currently can observe celestial objects in a unique region
in the short end of the ultraviolet portion of the electromagnetic
spectrum.

     Voyager's ultraviolet instruments are best suited to study the
two extreme phases of a star's life -- its birth and its death.  Thus
the Voyagers are currently gathering data on early blue stars as well
as other white dwarf stars nearing the end of their lifetime.
"Voyager is helping us get a better handle on exactly how much energy
these hot stars emit," Holberg said.

     Now that Voyager's primary mission of exploring the outer
planets is over, there are fewer constraints on the science team when
it comes to programming the spacecrafts' observations.  "We can sit
on these things for very long periods of time and watch these stars
go through their phases," Holberg said.

     Stars can be very active, but also unpredictable.  "We don't
know when a star will do something.  If we want to sit there and
wait, we can do it in the hopes that the star will go through an
outburst and Voyager will be there to observe it," he continued.
Voyager can now stare at an object for days and even weeks at a time
to thoroughly map it and the region around it.

     Since the beginning of the interstellar mission, the Voyager
project has been conducting a guest observer program which allows
astronomers from around the world to make proposals and apply for
time to use the Voyager ultraviolet spectrometer in much the same way
that astronomers apply for time at ground-based observatories.  This
program enables scientists to make simultaneous observations of the
same object using Voyager and ground-based telescopes.

     The cameras on the spacecraft have been turned off and the
ultraviolet instrument is the only experiment on the scan platform
that is still functioning.  Voyager scientists expect to continue to
receive data from the ultraviolet spectrometers at least until the
year 2000.  At that time, there will not be enough electrical power
for the heaters to keep the ultraviolet instrument warm enough to
operate.

     Yet there are several other fields and particle instruments that
can continue to send back data as long as the spacecraft stay alive.
They include the cosmic ray subsystem, the low-energy charged
particle instrument, the magnetometer, the plasma subsystem, the
plasma wave subsystem and the planetary radio astronomy instrument.
Barring any catastrophic events, JPL should be able to retrieve this
information for at least the next 20 and perhaps even the next 30
years.

     "In exploring the four outer planets, Voyager already has had an
epic journey of discovery.  Even so, their journey is less than half
over with more discoveries awaiting the first contact with
interstellar space," Stone said.  "The Voyagers revealed how limited
our imaginations really were about our solar system, and I expect
that as they continue toward interstellar space, they will again
surprise us with unimagined discoveries of this never-before-visited
place which awaits us beyond our planetary neighborhood."

      Voyager 1 is now 4.3 billion miles from Earth, traveling at a
heliocentric velocity of 39,700 mph.  Voyager 2, traveling in the
opposite direction from its twin, is 3.3 billion miles from Earth
with a heliocentric velocity of 36,800 mph.

     The VIM is managed by JPL and sponsored by NASA's Office of
Space Science and Applications, Wash., D. C.

Article: 19510
From: [email protected] (Glenn S. Johnson)
Newsgroups: sci.space,sci.astro
Subject: Re: Pioneer spaceprobes
Date: 12 Jan 92 12:03:56 GMT
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>,
[email protected] (Susan E. Kayser NSSDC/STX (301)513-1673) writes... 

>In article <[email protected]>,
>[email protected] writes... 
>>Is there anybody out there that could provide me with some information about
>>the Pioneer-10 and Pioneer-11 spaceprobes?
>> 
>>I know that they were launched in the beginning of the seventies in order to
>>explore some of the planets in our own solar system. Both have now left
>>the solar system in order to reach other stars. I've heard that Nasa still
>>receives signals from them. The data that is recovered is used to determine 
>>the effects of the solar wind outside the solar system.
>> 
>>Could anybody confirm this? Are they also used for other scientific
>>experiments besides the solar wind measurement? Are they even still alive?
> 
>This answer is off the top of my head, and I may have a few things wrong, 
>but...
> 
[good mission summary deleted]
>Susan Kayser		NCF::KAYSER  or  kayser%[email protected]
>Hughes/STX at NASA/GSFC/NSSDC
>Greenbelt, MD
 
This last week there was a study to find how to better measure the
range to Pioneer 10 and 11.  Unfortunately, these spacecraft did not
include a wideband ranging channel to handle standard DSN ranging. 
They might try a ramped tuning on the uplink and measure the round
trip time till the ramp is seen on the downlink to better the range
estimation.   If they do find something interesting, we want to know
how far out it is. 
 
As Susan mentioned, the Voyagers are more likely to last long enough
to find the heliopause (termination bow shock).  The current tracking
plan runs well beyond 2000.  The RTLT (round trip light time) to
Voyager 1 is 13 hours, 16 minutes, and 18 seconds.  Voyager 2 is 'much
closer', at 'just' 10 hours, 20 minutes, and 26 seconds.  The Voyager
2 RTLT is currently increasing about 6 seconds a day. 
 
Standard DSN (Deep Space Network) ranging uses a code of sequentially
higher frequencies modulated onto the uplink.  Spacecraft with a
ranging channel (most JPL spacecraft, many others) can turn this
signal around and transmit it back to the ground station.  The
received code is correlated with a stored model of the transmitted
code.  The end result is the range plus or minus a meter, out to the
edge of the solar system.  Doppler measurements can yield down to the cm. 
 
********************************************************************
Glenn S. Johnson,                   NASA's Jet Propulsion Laboratory
Internet: [email protected], [email protected]
X.400:(C:USA, ADMD:TELEMAIL, PRMD:NASAMAIL, O:NASA, UN:GSJOHNSON)
SPAN:  JPLLSI::GJOHNSON

Article: 19550
From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro
Subject: Re: Voyager 2 (was Pioneer spaceprobes)
Date: 14 Jan 92 22:16:04 GMT
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>
[email protected] (Susan E. Kayser NSSDC/STX (301)513-1673) writes: 

>As for "leaving the solar system in order to reach other stars", at their 
>current speed, it would take about 140,000 years to reach the nearest star--
>assuming either of the s/c were heading in that direction, which they aren't.  
>Their current (and final) directions were determined basically by the 
>requirements of their last planetary encounter trajectories. 
 
I have some numbers on "nearby" stars Voyager 2 will be passing by in
the next one million years. 
 
                     Year of Closest   Distance to Star
   Star              Approach          (in light years)
   ---------------   ---------------   ----------------
   Bernard's Star        8,571              4.03
   Proxima Centauri     20,319              3.21
   Alpha Centauri       20,629              3.47
   Lalande 21185        23,274              4.65
   Ross 248             40,176              1.65
   DM-36 13940          44,492              5.57
   AC+79 3888           46,330              2.77
   Ross 154            129,084              5.75
   DM+15 3364          129,704              3.44
   Sirius              296,036              4.32
   DM-5 4426           318,543              3.92
   44 Ophiuchi         442,385              6.72
   DM+27 1311          957,963              6.62
 
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't wait for your ship
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | to come in, paddle out to
|_____|/  |_|/       |_____|/                     | it.

 Gee, I thought Proxima Centauri was the closest star to us.  How come V
gets to Barnard's first?  Does Barnard curve its trajectory "back" towards
Proxima?

Burns

re .254

> Gee, I thought Proxima Centauri was the closest star to us.

It is.

>How come V. gets to Barnard's first?

It doesn't get that close.
    
You may be misinterpretting the table. It gives for nearby stars the year of
closest approach to the star and distance at closest approach and is sorted by
the former.

My spacial perception is fairly abysmal but...

Suppose V. were heading directly towards Alpha Centauri at the speed of light.
In that case it would arrive there in around four years so its closest approach
time would be 4 years and closest approach distance 0. Now imagine raising a
perpendicular from V.'s path at a distance of 1 l.y. from the Sun and with the
'height' of the perpendicular 5 l.y. Put a star at the top of the
perpendicular. For this second star the time of closest approach would be just 1
year but the closest approach distance 5 l.y.

>Does Barnard curve its trajectory "back" towards Proxima?

I doubt it.

It is not clear from the table what assumptions were made and what factors were
taken into account.

e.g. was proper motion of the stars considered
e.g. was a straight line path assumed or were some gravitational effects
	accounted for?

re .255

> Gee, I thought Proxima Centauri was the closest star to us.

It is.

No wonder I feel so cold...

    re .-1
    
    You may find it warmer at the Crescent. (-:
    
    Maybe I should have said that Proxima C. is the closest star to the Sun.

From:	DECWRL::"[email protected]" "MAIL-11 Daemon"  1-SEP-1992 
        11:22:20.40
To:	[email protected]
CC:	
Subj:	Voyager Update - 09/01/92

                              VOYAGER 1 STATUS REPORT
                                 September 1, 1992

     The Voyager project reports that they have experienced an
undetermined radio frequency failure on board the Voyager 1 spacecraft
on September 1, 1992 at 09:08Z over DSS-42 (Canberra 34 meter antenna).  
The project will conduct a detailed subsystem check later today. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     | 

From:	DECWRL::"[email protected]" "MAIL-11 Daemon"  1-SEP-1992 
        17:21:33.80
To:	[email protected]
CC:	
Subj:	Voyager 1 Update - 09/01/92

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. (818) 354-5011

                      Voyager Status Report
                        September 1, 1992

    The Voyager 1 spacecraft used its onboard fault protection program
to maintain communications with the ground this morning, after it
experienced a failure in the piece of equipment that allows the
spacecraft to send telemetry signals to Earth. 

    Ground controllers lost the downlink signal from Voyager 1 at 2:08
PDT this morning at the Tidbinbilla Deep Space Network tracking
station in Australia.  Telemetry data indicated a failure of the Ultra
Stable Oscillator as the cause of the loss of downlink signal. 

    Voyager 1 responded autonomously to the problem and switched to
the auxiliary oscillator.  The spacecraft reconfigured itself in less
than 10 minutes and continued sending telemetry to the ground.  Spacecraft 
controllers at JPL have no plans to change this current configuration. 

    Both the Voyager 1 and Voyager 2 spacecraft continue in good
health and are conducting fields and particles experiments and
ultraviolet observations.  Voyager 1 was launched 15 years ago this
week, on Sept. 5, 1977.  Voyager 2 was launched on Aug. 20, 1977. 

    Voyager 1 is currently 4.6 billion miles (7.4 billion kilometers) 
from Earth.

    Voyager 2 is currently 3.5 billion miles (5.6 billion kilometers) 
from Earth.

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     | 

Article 2282 of sci.space.news:
Newsgroups: sci.space.news
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: Voyager 1 Passes 50 AU Mark
Message-ID: <[email protected]>
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  Voyager 1, Voyager 2, JPL
Sender: [email protected] (Usenet)
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Reply-To: [email protected]
Organization: Jet Propulsion Laboratory
Date: Sun, 25 Oct 1992 02:35:40 GMT
Approved: [email protected]
Lines: 70

From the JPL Universe
Voyager 1 distance
10/23/92

	Voyager 1, one of two spacecraft launched in 1977 to explore
the outer planets, has gone more than 50 times the distance of
Earth to the sun -- a distance greater than the outermost reaches
of Pluto's orbit.

	Voyager project officials at NASA's Jet Propulsion
Laboratory said the spacecraft, which is headed upward from the
ecliptic, the plane where the planets orbit the sun, is searching
for the end of the sun's influence, called the heliopause.

	The spacecraft crossed the 50 astronomical units (AUs)
distance at 1:30 a.m. PDT Friday, October 9, and is even farther
from Earth, since our planet is going the other way in its orbit.
An astronomical unit is the Earth's mean distance from the sun,
or 93 million miles. 

	Voyager 1 was launched September 5, 1977, about two weeks
after its sister spacecraft, Voyager 2, was launched. Voyager 1,
on a faster trajectory, reached Jupiter on March 5, 1979, and
encountered Saturn November 12, 1980.

	From Saturn, Voyager 1 was turned by the planet's gravity
toward its upward journey, aimed 35 degrees above the ecliptic
plane. It is traveling at a rate of about 520 million kilometers
(about 320 million miles) a year.

	It is actually 7,480,357,296 kilometers (4,648,078,550
miles) from the sun.

	Voyager Project manager George Textor said the spacecraft,
as is its twin, is still operating and it is hoped it will
continue to return science data until it crosss the heliopause.
That boundary is believed to be 60 to 90 AU from the sun,
depending on the periods of the sun's activity.

 	 Voyager 2 encountered Jupiter, Saturn, Uranus and Neptune
and then, its trajectory bent by Neptune's gravity, headed south
of the ecliptic plane, also searching for the outer limit of the
solar wind and the beginning of interstellar space. It is now a
little more than 38 AUs from the sun.

	Two other NASA spacecraft also are in the outer areas of the
solar system. Pioneer 10 is more than 55 AUs from the sun, and
its sister spacecraft, Pioneer 11 is more than 36 AUs from the
sun.

	The two Voyagers gave the world the first detailed pictures
of the outer planets and volumes of scientific data on the giant
gas planets and their satellites.

	The Voyager mission was designed to take advantage of a rare
geometric alignment of the outer planets in the late 1970s and
the 1980s, the arrangement of Jupiter, Saturn, Uranus and
Neptune, which occurs only about every 175 years, allowed the
spacecraft to swing from one planet to the next without the need
for large onboard propulsion systems.

                                   #####

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | If God had wanted us to 
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | have elections, he would 
|_____|/  |_|/       |_____|/                     | have given us candidates.

Article: 2679
Newsgroups: sci.space.news
From: [email protected] (Jayant Murthy)
Subject: Voyager UVS shutdown
Sender: [email protected]
Organization: Johns Hopkins University
Date: Wed, 16 Dec 1992 21:47:14 GMT
  
>From [email protected]  Tue Dec  8 18:49:38 1992

Received: from jhufos.pha.jhu.edu by msx2.pha.jhu.edu via SMTP
          (920330.SGI/911001.SGI) 
	for murthy id AA07143; Tue, 8 Dec 92 18:49:38 -0500
Received: from STARS.GSFC.NASA.GOV by jhufos.pha.jhu.edu (4.1/SMI-4.1 JHUFOS)
	id AA07273; Tue, 8 Dec 92 18:47:07 EST
Date:    Tue, 8 Dec 1992 18:47:02 -0500 (EST)
From: [email protected] (Ron Oliversen GSFC/684 301-286-6290)
Message-Id: <[email protected]>
Subject: Voyager UVS termination notice
To: [email protected], [email protected], wpb@hut4, [email protected],
        [email protected], [email protected],
        [email protected], [email protected],
        [email protected], [email protected],
        [email protected], [email protected],
        [email protected], buss@hut4, [email protected]
X-Vmsmail-To: @VC_EMAIL.TXT
Status: RO
 
The Voyager Ultraviolet Spectrometer (UVS) Guest Observer (GO) Program
Scientist, Bob Stachnik/NASA HQ and the UVS GO Project Scientist, Ron
Oliversen/GSFC regretfully announce the termination of the UVS GO program.
The official statement from NASA Headquarters follows below. 
 
------------------------------------------------------------------------
 
   Responding to a cut of $2M to MO&DA (Mission Operations and Data
Analysis) funds, the Astrophysics Division has authorized termination of
the astronomical observing program using the Ultraviolet Spectrometers
(UVS) aboard Voyagers 1 and 2. 
 
   The budget reduction in question is the latest component of a series of
congressionally-imposed reductions to Physics and Astronomy MO&DA and R&A
(Research and Analysis) budgets. Until now, all recent cuts have been
absorbed by the Astrophysics Division in the form of reduced funding to
programs, which, nevertheless, remain in existence. This is the first
recent cut which has resulted in complete termination of a program. In the
case of Voyager UVS, the instrument providing the observations is operated
by the Space Physics Division under an agreement with the Astrophysics
Division. Since the cost savings from termination of UVS operations amount
to only a portion of the $2M cut, further reductions elsewhere in the
Astrophysics MO&DA Program will be necessary. 
 
   A termination date has not yet been set. A majority of the 1992
observations have been obtained. Those 1992 observers who have received,
or shortly will receive, their data will be allowed to retain the funds
associated with reduction of those data. It is expected that 1992 funds
sent to the University of Arizona for support of Guest Observers will
permit operations to continue until about May, 1993. 
 
   Members of the community should note the following statement, prepared
by Dr. Guenter Riegler, excerpted from a description of the current status
of the MO&DA program: 

    The science community should note that this period of rapid
    growth in MO&DA support is about to end.  The budget for MO&DA,
    including support for science grants, will be leveling off or
    perhaps decreasing, while more missions will be launched.  This
    requires that each of the three functional areas of MO&DA must be
    executed with increasing efficiency.  In the area of mission
    operations, NASA has begun an assessment of efficiency
    improvements through programmatic, organizational, technical, and
    motivational changes.  Science operations efforts, including
    science centers, will have to be pared down to the minimum level
    for a viable science analysis effort.  Finally, the usage of
    science grants also needs to be examined.  Among the options
    which have been adopted by other disciplines and agencies, and
    need to be discussed within the Space Astrophysics community as
    well, are: 1) ending missions after completion of their primary
    science objectives, 2) selecting a smaller number of larger
    observing and research programs, 3) reducing the number of
    multiple awards to the same investigator/group, and 4) divorcing
    funding from observing time awards. 

Article: 29889
From: [email protected] (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space,sci.astro
Subject: Re: Voyager UVS shutdown
Date: 17 Dec 92 15:44:09 -0600
Organization: Fermi National Accelerator Laboratory
 
In article <[email protected]>,
[email protected] (Jayant Murthy) writes: 

> The Voyager Ultraviolet Spectrometer (UVS) Guest Observer (GO) Program
> Scientist, Bob Stachnik/NASA HQ and the UVS GO Project Scientist, Ron
> Oliversen/GSFC regretfully announce the termination of the UVS GO program.
 
Ouch!  Bummer.  
 
The UVS has quietly been observing stellar spectra in the far
ultraviolet for many years.  To give this announcement some context, I
append excerpts from a 1990 posting I wrote. 
 
There was an article by J.B. Holberg and others giving results from
the UVS observations in *Journal of the British Interplanetary
Society* in the past year or so; sorry, don't have the citation handy.
 
==============================================
 
Now that all the planets on the Voyagers' itinerary have been passed,
some of their instruments are essentially useless.  The imaging and
infrared spectroscopy gadgets have nothing close enough or bright
enough to look at anymore.  As a one-time stunt (I almost said
"one-shot," but then remembered it's a mosaic (-:), Voyager 1 snapped
the "family portrait" showing the bodies of the Solar System as little
dots.  Data are back on the ground, and we oughta see the result any
week now.  The final frame of the portrait showed the Sun, and in
taking it solar heat may have damaged the shutter of one camera
permanently.  That's okay-- Voyager 1 will never need that camera
again.  (Barring flying saucer visits.)  If there is a scientific
purpose to the family portrait, I'm not aware of it.  But it's a nice
thing to have. 
 
Other instruments aboard continue to gather interesting information,
which is what JPL means by "routine cruise science."  The
particles-and-fields stuff reports on the environment at the edge of
the solar system; examples include the Plasma Wave System, the
Magnetometer, and Low Energy Charged Particle instrument.  As the
plutonium in the generators decays and power runs low in the years to
come, instruments and their heaters will be shut off, starting with
the cameras.  But the Voyager gang hopes to hit the heliopause-- the
boundary between the solar wind and the interstellar wind-- in the
next decade or two.  So they'll need as many of the P&F experiments 
running as they can manage.
 
One special case is the Ultraviolet Spectrometer (UVS), which sits on
the scan platform with the cameras and the infrared spectrometer.  Its
primary purpose is for looking at ultraviolet emission and absorption
lines in the atmospheres of planets.  It is sensitive to wavelengths
in the "extreme ultraviolet," between 500 and 1700 angstroms.  
 
It happens that not much astronomy has been done in these
wavelengths.  The galaxy has clouds of interstellar hydrogen.  A
"Lyman alpha" photon (912 angstroms, 13.6 electron volts) has enough
energy to ionize neutral hydrogen. Any photon of wavelength *shorter*
than this runs the risk of bumping into a hydrogen atom and getting
absorbed as it knocks the electron loose.  Now, there is not much
hydrogen in interstellar space.  There's a lot of room between
hydrogen atoms.  But over trillions upon trillions of kilometers, the
hydrogen adds up.  Beyond a few light-years, it's hard to see any
light with really short wavelengths, because it gets absorbed in the
interstellar hydrogen before it gets to us.
 
Consequently, the ultraviolet telescopes that have flown in space,
such as the International Ultraviolet Explorer, have not been given
the capability to see extreme ultraviolet (EUV) colors.  But the sky
isn't as opaque as people thought;  you can see *some* distance into
space in the EUV, and there is interesting physics going on in nearby
stars, especially extremely hot ones. 
 
The Voyager UVS instruments are the only currently flying which can
make measurements in the EUV.  They are small, and their spectral
resolution is only about 100 angstroms, but they have lots of leisure
time to make long exposures these days.  So there's an ongoing program
to use the UVS to study a series of stellar targets, which, I imagine,
will continue as long as they have the power to operate them.   [Hah!
--WSH, 1992] I'd speculate that the Voyager studies are valuable
precursors for planning such missions as the STS-35 ASTRO observatory,
carrying the Hopkins Ultraviolet Telescope [it flew once, and will fly
again --WSH, 1992], and the Extreme Ultraviolet Explorer, which will
make an all-sky survey.
 
     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
 /       \                          (_) (_)                    / | \
 |       |     Bill Higgins   Fermi National Accelerator Laboratory
 \       /     Bitnet:     [email protected]
   -   -       Internet:  [email protected]
     ~         SPAN/Hepnet:      43011::HIGGINS 

Article 2965 of sci.space.news:
Newsgroups: sci.space.news
Path: nntpd2.cxo.dec.com!nntpd.lkg.dec.com!news.crl.dec.com!deccrl!caen!uwm.edu!spool.mu.edu!agate!ames!dont-send-mail-to-path-lines
From: [email protected] (Ron Baalke)
Subject: Voyager Update - 01/29/93
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41    
Keywords: Voyager 1, Voyager 2
Sender: [email protected]
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Fri, 29 Jan 1993 16:37:00 GMT
Approved: [email protected]
Lines: 24

From the NASA Daily News
January 29, 1993

JPL also reports that the two Voyager spacecraft are also
doing fine.  Voyager 1 is now 4.7 billion miles (7.6
billion kilometers) from the Sun heading outward.
Voyager 2 is 3.6 billion miles from the sun (5.8 billion
km) and also heading outward.  Both spacecraft were
launched in Fall 1977 and use radioisotope-
thermoelectric-generators which were built in 1976 and
which are still providing electric power for the
spacecraft nearly 17 years later.  The two Voyagers along
with Pioneers 10 and 11 are providing scientists with
continuing data on the extreme distant composition of the
solar wind.  The radio signals from the four spacecraft
are also being used as part of gravitational studies of
the mass and objects in our solar system.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |

Article 3808 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: Voyager Discovers First Direct Evidence of the Heliopause
Message-ID: <[email protected]>
To: [email protected]
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.41    
Keywords: Voyager, JPL
Sender: [email protected]
Nntp-Posting-Host: kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Wed, 26 May 1993 16:01:00 GMT
Approved: [email protected]
Lines: 113

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                        May 26, 1993
(Phone:  202/358-0883)                   

Mary A. Hardin
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone:  818/354-5011)

RELEASE:  93-099

VOYAGER SPACECRAFT FIND CLUE TO ANOTHER SOLAR SYSTEM MYSTERY

     Nearly 15 years after they left home, the Voyager 1 and 2
spacecraft have discovered the first direct evidence of the long-
sought-after heliopause -- the boundary that separates Earth's
solar system from interstellar space.

     "This discovery is an exciting indication that still more
discoveries and surprises lie ahead for the Voyagers as they
continue their journey to the outer reaches of our solar system,"
said Dr. Edward C. Stone, Director of the Jet Propulsion
Laboratory (JPL), Pasadena, Calif., and Voyager Project Scientist.

     Since August 1992, the radio antennas on the spacecraft,
called the plasma wave subsystem, have been recording intense low-
frequency radio emissions coming from beyond the solar system.
For months the source of these radio emissions remained a mystery.

     "Our interpretation now is that these radio signals are
created as a cloud of electrically charged gas, called a plasma,
expands from the sun and interacts with the cold interstellar gas
beyond the heliopause," said Dr. Don Gurnett, Principal
Investigator of the Voyager plasma wave subsystem and a professor
at the University of Iowa.

     The sun is the center of our solar system.  The solar wind is
a stream of electrically charged particles that flows steadily
away from the sun.   As the solar wind moves out into space, it
creates a magnetized bubble of hot plasma around the sun, called
the heliosphere.  Eventually, the expanding solar wind encounters
the charged particles and magnetic field in the interstellar gas.
The boundary created between the solar wind and interstellar gas
is the heliopause.

     "These radio emissions are probably the most powerful radio
source in our solar system," said Gurnett.  "We've estimated the
total power radiated by the signals to be more than 10 trillion
watts.  However, these radio signals are at such low frequencies,
only 2 to 3 kilohertz, that they can't be detected from Earth."

     In May and June 1992, the sun experienced a period of intense
solar activity which emitted a cloud of rapidly moving charged
particles.  When this cloud of plasma arrived at the heliopause,
the particles interacted violently with the interstellar plasma
and produced the radio emissions, according to Gurnett.

     "We've seen the frequency of these radio emissions rise over
time. Our assumption that this is the heliopause is based on the
fact that there is no other known structure out there that could
be causing these signals," Gurnett continued.

     Because of the Voyagers' unique positions in space, they
serendipitously detected and recorded the radio emissions.
"Earth-bound scientists would not know this phenomenon was
occurring if it weren't for the Voyager spacecraft," Gurnett
added.

     Exactly where the heliopause is remains one of the great
unanswered questions in space physics.

     "It's this Voyager radio data combined with the plasma
measurements taken at the spacecraft that give us a better guess
about where the heliopause is.  Based on the solar wind speed, the
time that has elapsed since the mid-1992 solar event and the
strength of the radio emissions, my best guess for the upper limit
of the heliopause currently is about 90 to 120 astronomical units
(AU) from the sun," said Dr. Ralph McNutt, a co-investigator on
the Voyager plasma science experiment and a researcher at the
Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
(One AU is equal to 93 million miles (150 million kilometers) or
the mean distance from the Earth to the sun.)

     Voyager 1 currently is at 52 AU (4.9 billion miles or 7.8
billion kilometers from the sun), and Voyager 2 is at 40 AU (3.7
billion miles or 6 billion kilometers) from the sun.

     Voyager 1 was launched on Sept. 5, 1977 and completed flyby
exploration of both Jupiter and Saturn.  The spacecraft now is
rising above the ecliptic plane -- the plane in which most of the
planets orbit the sun -- at an angle of about 35 degrees at a rate
of about 320 million miles (about 520 million kilometers) a year.

     Voyager 2 was launched on Aug. 20, 1977 and also completed
visits to Jupiter and Saturn and then went on to explore Uranus
and Neptune, completing the reconnaissance of the giant outer
planets.  The spacecraft is now diving below the ecliptic plane at
an angle of about 48 degrees and a rate of about 290 million miles
(about 470 million kilometers) a year.

     Gurnett presented his findings today at a meeting of the
American Geophysical Union in Baltimore.

     The Voyager Interstellar Mission is managed by JPL for NASA's
Office of Space Science, Washington, D.C.

- end -
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Never laugh at anyone's
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/  |_|/       |_____|/                     | 

Article 1346 of alt.sci.planetary:
Xref: nntpd2.cxo.dec.com sci.space:63707 sci.astro:36824 alt.sci.planetary:1346
Path: nntpd2.cxo.dec.com!nntpd.lkg.dec.com!pa.dec.com!decwrl!elroy.jpl.nasa.gov!kelvin.jpl.nasa.gov!baalke
From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Re: Voyager Discovers the First Direct Evidence of the Heliopause
Date: 26 May 1993 23:09 UT
Organization: Jet Propulsion Laboratory
Lines: 27
Distribution: world
Message-ID: <[email protected]>
References: <[email protected]> <[email protected]>
NNTP-Posting-Host: kelvin.jpl.nasa.gov
Keywords: Voyager, JPL
News-Software: VAX/VMS VNEWS 1.41    

In article <[email protected]>, [email protected] (Roger Noe) writes...
>In what range of time are Voyager 1 and 2 expected to actually reach
>the heliopause?  Will there be a pronounced discontinuity, where it
>can be said objectively that the satellites have "reached the
>heliopause", or is this more of a continuum and a subjective
>determination of where the heliopause begins?

Assuming the heliopause is at 100 AU, then Voyager 1 will reach it
first in the year 2010.  Both spacecraft should still be operating
by then and we will still be in contact with them.  It is suspected
that boundary is like a bow shock, so should be easily detectable
when the spacecraft passes through it.

>Didn't something similar happen when each of our interplanetary
>satellites reached Earth's magnetopause?  Isn't there at least a
>qualitative similarity between these two "boundaries"?

This is similar to the magnetosphere's of the other planets.  In fact,
I wouldn't be surprised if the heliopause fluctuated a bit, so the spacecraft
may actually cross the boundary multiple times.  
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Never laugh at anyone's
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | dreams.
|_____|/  |_|/       |_____|/                     | 

    Note for DECwindows users...
    The next reply (Voyager Mission FAct Sheet) is over 600 lines.
    
    It may take a while to load.
    
    Regards,
    
    JB

Article 4022 of sci.space.news:

FACT SHEET:           THE VOYAGER MISSION
                          June 1993

     The twin spacecraft Voyager 1 and Voyager 2 were launched by
NASA in separate months in the summer of 1977 from Cape
Canaveral, Florida.  As originally designed, the Voyagers were to
conduct closeup studies of Jupiter and Saturn, Saturn's rings,
and the larger moons of the two planets.

     To accomplish their two-planet mission, the spacecraft were
built to last five years.  But as the mission went on, and with
the successful achievement of all its objectives, the additional
flybys of the two outermost giant planets, Uranus and Neptune,
proved possible -- and irresistible to mission scientists and
engineers at the Voyagers' home at the Jet Propulsion Laboratory
in Pasadena, California.

     As the spacecraft flew across the solar system,
remote-control reprogramming was used to endow the Voyagers with
greater capabilities than they possessed when they left the
Earth.  Their two-planet mission became four.  Their five-year
lifetimes stretched to 12 and more.

     Eventually, between them, Voyager 1 and 2 would explore all
the giant outer planets of our solar system, 48 of their moons,
and the unique systems of rings and magnetic fields those planets
possess.

     Had the Voyager mission ended after the Jupiter and Saturn
flybys alone, it still would have provided the material to
rewrite astronomy textbooks.  But having doubled their already
ambitious itineraries, the Voyagers returned to Earth information
over the years that has revolutionized the science of planetary
astronomy, helping to resolve key questions while raising
intriguing new ones about the origin and evolution of the planets
in our solar system.


HISTORY OF THE VOYAGER MISSION

      The Voyager mission was designed to take advantage of a
rare geometric arrangement of the outer planets in the late 1970s
and the 1980s.  This layout of Jupiter, Saturn, Uranus and
Neptune, which occurs about every 175 years, allows a spacecraft
on a particular flight path to swing from one planet to the next
without the need for large onboard propulsion systems.  The flyby
of each planet bends the spacecraft's flight path and increases
its velocity enough to deliver it to the next destination.
Using this "gravity assist" technique, the flight time to Neptune
can be reduced from 30 years to 12.

     While the four-planet mission was known to be possible, it
was deemed to be too expensive to build a spacecraft that could
go the distance, carry the instruments needed and last long
enough to accomplish such a long mission.  Thus, the Voyagers
were funded to conduct intensive flyby studies of Jupiter and
Saturn only.  More than 10,000 trajectories were studied before
choosing the two that would allow close flybys of Jupiter and its
large moon Io, and Saturn and its large moon Titan; the chosen
flight path for Voyager 2 also preserved the option to continue
on to Uranus and Neptune.

     From the NASA Kennedy Space Center at Cape Canaveral,
Florida, Voyager 2 was launched first, on August 20, 1977;
Voyager 1 was launched on a faster, shorter trajectory on
September 5, 1977.  Both spacecraft were delivered to space
aboard Titan-Centaur expendable rockets.

     The prime Voyager mission to Jupiter and Saturn brought
Voyager 1 to Jupiter on March 5, 1979, and Saturn on November 12,
1980, followed by Voyager 2 to Jupiter on July 9, 1979, and
Saturn on August 25, 1981.

     Voyager 1's trajectory, designed to send the spacecraft
closely past the large moon Titan and behind Saturn's rings, bent
the spacecraft's path inexorably northward out of the ecliptic
plane -- the plane in which most of the planets orbit the Sun.
Voyager 2 was aimed to fly by Saturn at a point that would
automatically send the spacecraft in the direction of Uranus.

     After Voyager 2's successful Saturn encounter, it was shown
that Voyager 2 would likely be able to fly on to Uranus with all
instruments operating.  NASA provided additional funding to
continue operating the two spacecraft and authorized JPL to
conduct a Uranus flyby.  Subsequently, NASA also authorized the
Neptune leg of the mission, which was renamed the Voyager Neptune
Interstellar Mission.

     Voyager 2 encountered Uranus on January 24, 1986, returning
detailed photos and other data on the planet, its moons, magnetic
field and dark rings. Voyager 1, meanwhile, continues to press
outward, conducting studies of interplanetary space.  Eventually,
its instruments may be the first of any spacecraft to sense the
heliopause -- the boundary between the end of the Sun's magnetic
influence and the beginning of interstellar space.

     Following Voyager 2's closest approach to Neptune on August
25, 1989, the spacecraft flew southward, below the ecliptic plane
and onto a course that will take it, too, to interstellar space.
Reflecting the Voyagers' new transplanetary destinations, the
project is now known as the Voyager Interstellar Mission.

     Voyager 1 is now leaving the solar system, rising above the
ecliptic plane at an angle of about 35 degrees at a rate of about
520 million kilometers (about 320 million miles) a year.  Voyager
2 is also headed out of the solar system, diving below the
ecliptic plane at an angle of about 48 degrees and a rate of
about 470 million kilometers (about 290 million miles) a year.

     Both spacecraft will continue to study ultraviolet sources
among the stars, and the fields and particles instruments aboard
the Voyagers will continue to search for the boundary between the
Sun's influence and interstellar space.  The Voyagers are
expected to return valuable data for two or three more decades.
Communications will be maintained until the Voyagers' nuclear
power sources can no longer supply enough electrical energy to
power critical subsystems.

     The cost of the Voyager 1 and 2 missions -- including
launch, mission operations from launch through the Neptune
encounter and the spacecraft's nuclear batteries (provided by the
Department of Energy) -- is $865 million.  NASA budgeted an
additional $30 million to fund the Voyager Interstellar Mission
for two years following the Neptune encounter.


VOYAGER OPERATIONS

      Voyagers 1 and 2 are identical spacecraft.  Each is
equipped with instruments to conduct 10 different experiments.
The instruments include television cameras, infrared and
ultraviolet sensors, magnetometers, plasma detectors, and
cosmic-ray and charged-particle sensors.  In addition, the
spacecraft radio is used to conduct experiments.

     The Voyagers travel too far from the Sun to use solar
panels; instead, they were equipped with power sources called
radioisotope thermoelectric generators (RTGs).  These devices,
used on other deep space missions, convert the heat produced from
the natural radioactive decay of plutonium into electricity to
power the spacecraft instruments, computers, radio and other
systems.

     The spacecraft are controlled and their data returned
through the Deep Space Network (DSN), a global spacecraft
tracking system operated by JPL for NASA.  DSN antenna complexes
are located in California's Mojave Desert; near Madrid, Spain;
and in Tidbinbilla, near Canberra, Australia.

     The Voyager project manager for the Interstellar Mission is
George P. Textor of JPL.  The Voyager project scientist is Dr.
Edward C. Stone of the California Institute of Technology.  The
assistant project scientist for the Jupiter flyby was Dr. Arthur
L. Lane, followed by Dr. Ellis D. Miner for the Saturn, Uranus
and Neptune encounters.  Both are with JPL.  The Voyager program
manager at NASA Headquarters in Washington D.C. is Ann Megwarth.
The program scientist, also at NASA Headquarters, is Dr. William
Brunk.


JUPITER

     Voyager 1 made its closest approach to Jupiter on March 5,
1979, and Voyager 2 followed with its closest approach occurring
on July 9, 1979.  The first spacecraft flew within 206,700
kilometers (128,400 miles) of the planet's cloud tops, and
Voyager 2 came within 570,000 kilometers (350,000 miles).

     Jupiter is the largest planet in the solar system, composed
mainly of hydrogen and helium, with small amounts of methane,
ammonia, water vapor, traces of other compounds and a core of
melted rock and ice.  Colorful latitudinal bands and atmospheric
clouds and storms illustrate Jupiter's dynamic weather system.
The giant planet is now known to possess 16 moons.  The planet
completes one orbit of the Sun each 11.8 years and its day is 9
hours, 55 minutes.

     Although astronomers had studied Jupiter through telescopes
on Earth for centuries, scientists were surprised by many of the
Voyager findings.

     The Great Red Spot was revealed as a complex storm moving in
a counterclockwise direction.  An array of other smaller storms
and eddies were found throughout the banded clouds.  

     Discovery of active volcanism on the satellite Io was easily
the greatest unexpected discovery at Jupiter.  It was the first
time active volcanoes had been seen on another body in the solar
system.  Together, the Voyagers observed the eruption of nine
volcanoes on Io, and there is evidence that other eruptions
occurred between the Voyager encounters.

     Plumes from the volcanoes extend to more than 300 kilometers
(190 miles) above the surface.   The Voyagers observed material
ejected at velocities up to a kilometer per second.

     Io's volcanoes are apparently due to heating of the
satellite by tidal pumping.  Io is perturbed in its orbit by
Europa and Ganymede, two other large satellites nearby, then
pulled back again into its regular orbit by Jupiter.  This
tug-of-war results in tidal bulging as great as 100 meters (330
feet) on Io's surface, compared with typical tidal bulges on
Earth of one meter (three feet).

     It appears that volcanism on Io affects the entire jovian
system, in that it is the primary source of matter that pervades
Jupiter's magnetosphere -- the region of space surrounding the
planet influenced by the jovian magnetic field.  Sulfur, oxygen
and sodium, apparently erupted by Io's many volcanoes and
sputtered off the surface by impact of high-energy particles,
were detected as far away as the outer edge of the magnetosphere
millions of miles from the planet itself.

     Europa displayed a large number of intersecting linear
features in the low-resolution photos from Voyager 1.  At first,
scientists believed the features might be deep cracks, caused by
crustal rifting or tectonic processes.  The closer
high-resolution photos from Voyager 2, however, left scientists
puzzled:  The features were so lacking in topographic relief that
as one scientist described them, they "might have been painted on
with a felt marker."  There is a possibility that Europa may be
internally active due to tidal heating at a level one-tenth or
less than that of Io.  Europa is thought to have a thin crust
(less than 30 kilometers or 18 miles thick) of water ice,
possibly floating on a 50-kilometer-deep (30-mile) ocean.

     Ganymede turned out to be the largest moon in the solar
system, with a diameter measuring 5,276 kilometers (3,280 miles). 
It showed two distinct types of terrain -- cratered and grooved
-- suggesting to scientists that Ganymede's entire icy crust has
been under tension from global tectonic processes.

     Callisto has a very old, heavily cratered crust showing
remnant rings of enormous impact craters.  The largest craters
have apparently been erased by the flow of the icy crust over
geologic time.  Almost no topographic relief is apparent in the
ghost remnants of the immense impact basins, identifiable only by
their light color and the surrounding subdued rings of concentric
ridges. 

     A faint, dusty ring of material was found around Jupiter. 
Its outer edge is 129,000 kilometers (80,000 miles) from the
center of the planet, and it extends inward about 30,000
kilometers (18,000 miles).

     Two new, small satellites, Adrastea and Metis, were found
orbiting just outside the ring.  A third new satellite, Thebe,
was discovered between the orbits of Amalthea and Io.

     Jupiter's rings and moons exist within an intense radiation
belt of electrons and ions trapped in the planet's magnetic
field.  These particles and fields comprise the jovian
magnetosphere, or magnetic environment, which extends three to
seven million kilometers toward the Sun, and stretches in a
windsock shape at least as far as Saturn's orbit -- a distance of
750 million kilometers (460 million miles).

     As the magnetosphere rotates with Jupiter, it sweeps past Io
and strips away about 1,000 kilograms (one ton) of material per
second.  The material forms a torus, a doughnut-shaped cloud of
ions that glow in the ultraviolet.  The torus's heavy ions
migrate outward, and their pressure inflates the jovian
magnetosphere to more than twice its expected size.  Some of the
more energetic sulfur and oxygen ions fall along the magnetic
field into the planet's atmosphere, resulting in auroras.

     Io acts as an electrical generator as it moves through
Jupiter's magnetic field, developing 400,000 volts across its
diameter and generating an electric current of 3 million amperes 
that flows along the magnetic field to the planet's ionosphere.


SATURN

     The Voyager 1 and 2 Saturn flybys occurred nine months
apart, with the closest approaches falling on November 12 and
August 25, 1981. Voyager 1 flew within 64,200 kilometers (40,000
miles) of the cloud tops, while Voyager 2 came within 41,000
kilometers (26,000 miles).

     Saturn is the second largest planet in the solar system.  It
takes 29.5 Earth years to complete one orbit of the Sun, and its
day was clocked at 10 hours, 39 minutes.  Saturn is known to have
at least 17 moons and a complex ring system.  Like Jupiter,
Saturn is mostly hydrogen and helium.  Its hazy yellow hue was
found to be marked by broad atmospheric banding similar to but
much fainter than that found on Jupiter.  Close scrutiny by
Voyager's imaging systems revealed long-lived ovals and other
atmospheric features generally smaller than those on Jupiter.

     Perhaps the greatest surprises and the most puzzles were
found by the Voyagers in Saturn's rings.  It is thought that the
rings formed from larger moons that were shattered by impacts of
comets and meteoroids.  The resulting dust and boulder- to
house-size particles have accumulated in a broad plane around the
planet varying in density.

     The irregular shapes of Saturn's eight smallest moons
indicates that they too are fragments of larger bodies. Unexpected 
structure such as kinks and spokes were found in addition to
thin rings and broad, diffuse rings not observed from Earth. 
Much of the elaborate structure of some of the rings is due to
the gravitational effects of nearby satellites.  This phenomenon
is most obviously demonstrated by the relationship between the
F-ring and two small moons that "shepherd" the ring material. 
The variation in the separation of the moons from the ring may
the ring's kinked appearance.  Shepherding moons were also found
by Voyager 2 at Uranus.

      Radial, spoke-like features in the broad B-ring were found
by the Voyagers.  The features are believed to be composed of
fine, dust-size particles.  The spokes were observed to form and
dissipate in time-lapse images taken by the Voyagers.  While
electrostatic charging may create spokes by levitating dust
particles above the ring, the exact cause of the formation of the
spokes is not well understood.

     Winds blow at extremely high speeds on Saturn -- up to 1,800
kilometers per hour (1,100 miles per hour).  Their primarily
easterly direction indicates that the winds are not confined to
the top cloud layer but must extend at least 2,000 kilometers
(1,200 miles) downward into the atmosphere.  The characteristic
temperature of the atmosphere is 95 kelvins.

     Saturn holds a wide assortment of satellites in its orbit,
ranging from Phoebe, a small moon that travels in a retrograde
orbit and is probably a captured asteroid, to Titan, the
planet-sized moon with a thick nitrogen-methane atmosphere. 
Titan's surface temperature and pressure are 94 kelvins (-292
Fahrenheit) and 1.5 atmospheres.  Photochemistry converts some
atmospheric methane to other organic molecules, such as ethane,
that is thought to accumulate in lakes or oceans.  Other more
complex hydrocarbons form the haze particles that eventually fall
to the surface, coating it with a thick layer of organic matter. 
The chemistry in Titan's atmosphere may strongly resemble that
which occurred on Earth before life evolved.

     The most active surface of any moon seen in the Saturn
system was that of Enceladus.  The bright surface of this moon,
marked by faults and valleys, showed evidence of tectonically
induced change.  Voyager 1 found the moon Mimas scarred with a
crater so huge that the impact that caused it nearly broke the
satellite apart.

     Saturn's magnetic field is smaller than Jupiter's, extending
only one or two million kilometers.  The axis of the field is
almost perfectly aligned with the rotation axis of the planet.  


URANUS

      In its first solo planetary flyby, Voyager 2 made its
closest approach to Uranus on January 24, 1986, coming within
81,500 kilometers (50,600 miles) of the planet's cloud tops.

     Uranus is the third largest planet in the solar system.  It
orbits the Sun at a distance of about 2.8 billion kilometers (1.7
billion miles) and completes one orbit every 84 years.  The
length of a day on Uranus as measured by Voyager 2 is 17 hours,
14 minutes.

     Uranus is distinguished by the fact that it is tipped on its
side.  Its unusual position is thought to be the result of a
collision with a planet-sized body early in the solar system's
history.  Given its odd orientation, with its polar regions
exposed to sunlight or darkness for long periods, scientists were
not sure what to expect at Uranus. 

      Voyager 2 found that one of the most striking influences of
this sideways position is its effect on the tail of the magnetic
field, which is itself tilted 60 degrees from the planet's axis
of rotation.  The magnetotail was shown to be twisted by the
planet's rotation into a long corkscrew shape behind the planet.

     The presence of a magnetic field at Uranus was not known
until Voyager's arrival.  The intensity of the field is roughly
comparable to that of Earth's, though it varies much more from
point to point because of its large offset from the center of
Uranus.  The peculiar orientation of the magnetic field suggests
that the field is generated at an intermediate depth in the
interior where the pressure is high enough for water to become
electrically conducting.

     Radiation belts at Uranus were found to be of an intensity
similar to those at Saturn.  The intensity of radiation within
the belts is such that irradiation would quickly darken (within
100,000 years) any methane trapped in the icy surfaces of the
inner moons and ring particles.  This may have contributed to the
darkened surfaces of the moons and ring particles, which are
almost uniformly gray in color.

     A high layer of haze was detected around the sunlit pole,
which also was found to radiate large amounts of ultraviolet
light, a phenomenon dubbed "dayglow."  The average temperature is
about 60 kelvins (-350 degrees Fahrenheit).   Surprisingly, the
illuminated and dark poles, and most of the planet, show nearly
the same temperature at the cloud tops.

     Voyager found 10 new moons, bringing the total number to 15. 
Most of the new moons are small, with the largest measuring about
150 kilometers (about 90 miles) in diameter.

     The moon Miranda, innermost of the five large moons, was
revealed to be one of the strangest bodies yet seen in the solar
system.  Detailed images from Voyager's flyby of the moon showed
huge fault canyons as deep as 20 kilometers (12 miles), terraced
layers, and a mixture of old and young surfaces.  One theory
holds that Miranda may be a reaggregration of material from an
earlier time when the moon was fractured by an violent impact. 

     The five large moons appear to be ice-rock conglomerates
like the satellites of Saturn.  Titania is marked by huge fault
systems and canyons indicating some degree of geologic, probably
tectonic, activity in its history.  Ariel has the brightest and
possibly youngest surface of all the Uranian moons and also
appears to have undergone geologic activity that led to many
fault valleys and what seem to be extensive flows of icy
material.  Little geologic activity has occurred on Umbriel or
Oberon, judging by their old and dark surfaces.

     All nine previously known rings were studied by the
spacecraft and showed the Uranian rings to be distinctly
different from those at Jupiter and Saturn.  The ring system may
be relatively young and did not form at the same time as Uranus. 
Particles that make up the rings may be remnants of a moon that
was broken by a high-velocity impact or torn up by gravitational
effects.


NEPTUNE

     When Voyager flew within 5,000 kilometers (3,000 miles) of
Neptune on August 25, 1989, the planet was the most distant
member of the solar system from the Sun.  (Pluto once again will
become most distant in 1999.)

      Neptune orbits the Sun every 165 years.  It is the smallest
of our solar system's gas giants.  Neptune is now known to have
eight moons, six of which were found by Voyager.  The length of a
Neptunian day has been determined to be 16 hours, 6.7 minutes.

     Even though Neptune receives only three percent as much
sunlight as Jupiter does, it is a dynamic planet and surprisingly
showed several large, dark spots reminiscent of Jupiter's
hurricane-like storms.  The largest spot, dubbed the Great Dark
Spot, is about the size of Earth and is similar to the Great Red
Spot on Jupiter.  A small, irregularly shaped, eastward-moving
cloud was observed "scooting" around Neptune every 16 hours or
so; this "scooter," as Voyager scientists called it, could be a
cloud plume rising above a deeper cloud deck.

     Long, bright clouds, similar to cirrus clouds on Earth, were
seen high in Neptune's atmosphere.  At low northern latitudes,
Voyager captured images of cloud streaks casting their shadows on
cloud decks below.

     The strongest winds on any planet were measured on Neptune. 
Most of the winds there blow westward, or opposite to the
rotation of the planet.  Near the Great Dark Spot, winds blow up
to 2,000 kilometers (1,200 miles) an hour.

     The magnetic field of Neptune, like that of Uranus, turned
out to be highly tilted -- 47 degrees from the rotation axis and
offset at least 0.55 radii (about 13,500 kilometers or 8,500
miles) from the physical center.  Comparing the magnetic fields
of the two planets, scientists think the extreme orientation may
be characteristic of flows in the interiors of both Uranus and
Neptune -- and not the result in Uranus's case of that planet's
sideways orientation, or of any possible field reversals at
either planet.  Voyager's studies of radio waves caused by the
magnetic field revealed the length of a Neptunian day.  The
spacecraft also detected auroras, but much weaker than those on
Earth and other planets.

     Triton, the largest of the moons of Neptune, was shown to be
not only the most intriguing satellite of the Neptunian system,
but one of the most interesting in all the solar system.  It
shows evidence of a remarkable geologic history, and Voyager 2
images showed active geyser-like eruptions spewing invisible
nitrogen gas and dark dust particles several kilometers into the
tenuous atmosphere.  Triton's relatively high density and
retrograde orbit offer strong evidence that Triton is not an
original member of Neptune's family but is a captured object.  If
that is the case, tidal heating could have melted Triton in its
originally eccentric orbit, and the moon might even have been
liquid for as long as one billion years after its capture by
Neptune.

     An extremely thin atmosphere extends about 800 kilometer
(500 miles) above Triton's surface.  Nitrogen ice particles may
form thin clouds a few kilometers above the surface.  The
atmospheric pressure at the surface is about 14 microbars,
1/70,000th the surface pressure on Earth.  The surface
temperature is about 38 kelvins (-391 degrees Fahrenheit) the
coldest temperature of any body known in the solar system.

     The new moons found at Neptune by Voyager are all small and
remain close to Neptune's equatorial plane.  Names for the new
moons were selected from mythology's water deities by the
International Astronomical Union, they are: Naiad, Thalassa,
Despina, Galatea, Larissa, Proteus.

     Voyager 2 solved many of the questions scientists had about
Neptune's rings.  Searches for "ring arcs," or partial rings,
showed that Neptune's rings actually are complete, but are so
diffuse and the material in them so fine that they could not be
fully resolved from Earth.  From the outermost in, the rings 
have been designated Adams, Plateau, Le Verrier and Galle.


INTERSTELLAR MISSION

     The spacecraft are continuing to return data about
interplanetary space and some of our stellar neighbors near the
edges of the Milky Way.

     As the Voyagers cruise gracefully in the solar wind, their
fields, particles and waves instruments are studying the space
around them.  In May 1993, scientists concluded that the plasma
wave experiment was picking up radio emissions that originate at
the heliopause -- the outer edge of our solar system.

     The heliopause is the outermost boundary of the solar wind,
where the interstellar medium restricts the outward flow of the
solar wind and confines it within a magnetic bubble called the
heliosphere.  The solar wind is made up of electrically charged
atomic particles, composed primarily of ionized hydrogen, that
stream outward from the Sun.

     Exactly where the heliopause is has been one of the great
unanswered questions in space physics.  By studying the radio
emissions, scientists now theorize the heliopause exists some 90 to
120 astronomical units (AU) from the Sun.  (One AU is equal to 150
million kilometers (93 million miles), or the distance from the
Earth to the Sun.

     The Voyagers have also become space-based ultraviolet
observatories and their unique location in the universe gives
astronomers the best vantage point they have ever had for looking
at celestial objects that emit ultraviolet radiation.

     The cameras on the spacecraft have been turned off and the
ultraviolet instrument is the only experiment on the scan platform
that is still functioning.  Voyager scientists expect to continue
to receive data from the ultraviolet spectrometers at least until
the year 2000.  At that time, there not be enough electrical power
for the heaters to keep the ultraviolet instrument warm enough to
operate.

     Yet there are several other fields and particle instruments
that can continue to send back data as long as the spacecraft stay
alive.  They include:  the cosmic ray subsystem, the low-energy
charge particle instrument, the magnetometer, the plasma subsystem,
the plasma wave subsystem and the planetary radio astronomy
instrument.  Barring any catastrophic events, JPL should be able to
retrieve this information for least the next 20 and perhaps event
the next 30 years.
                              #####

            Diameter                   Distance from Sun

Jupiter     142,984 km/88,846 mi    778,000,000 km/483,000,000 mi

Jupiter's Moons:                      Distance From Planet Center

Metis       40 km/25 mi                      128,000 km/79,500 mi
Adrastea    24x20x14 km/14x12x9 mi           129,000 km/80,100 mi
Amalthea    270x166x150 km/165x103x95 mi    181,300 km/112,600 mi
Thebe       110x90km/65x55 mi               222,000 km/138,000 mi
Io          3,630 km/2,225 mi               422,000 km/262,000 mi
Europa      3,138 km/1,949 mi               661,000 km/414,500 mi
Ganymede    5,262 km/3,269 mi             1,070,000 km/664,900 mi
Callisto    4,800 km/3,000 mi            1,883,000 km/1,170000 mi
Leda        16 km/10 mi                11,094,000 km/6,900,000 mi
Himalia     186 km/115 mi              11,480,000 km/7,133,000 mi
Lysithia    36 km/20 mi                11,720,000 km/7,282,000 mi
Elara       76 km/47 mi                11,737,000 km/7,293,000 mi
Ananke      30/18 mi                  21,200,000 km/13,173,000 mi
Carme       40 km/25 mi               22,600,000 km/14,043,000 mi
Pasiphae    50 km/31 mi               23,500,000 km/14,602,000 mi
Sinope      36 km/22 mi               23,700,000 km/14,727,000 mi


            Diameter                            Distance from Sun

Saturn      120,536 km/74,900 mi   1.4  billion km/870 million mi

Saturn's Moons                        Distance from Planet Center

Atlas       40x20 km/24x12 mi                137,670 km/85,500 mi
Prometheus  140x100x80 km/85x60x50 mi        139,353 km/86,600 mi
Pandora     110x90x80 km/70x55x50 mi         141,700 km/88,500 mi
Epimetheus  140x120x100 km/85x70x60 mi       151,472 km/94,124 mi
Janus       220x200x160 km/135x125x100 mi    151,422 km/94,093 mi
Mimas       392 km/243 mi                   185,520 km/115,295 mi
Enceladus   520 km/320 mi                   238,020 km/147,900 mi
Tethys      1,060 km/660 km                 294,660 km/183,100 mi
Telesto     34x28x26 km/20x17x16 mi         294,660 km/183,100 mi
Calypso     34x22x22 km/20x13x13 mi         294,660 km/183,100 mi
Dione       1,120 km/695 mi                 377,400 km/234,500 mi
Helene      36x32x30 km/22x20x19 mi         377,400 km/234,900 mi
Rhea        1,530 km/950 mi                 527,040 km/327,500 mi
Titan       5,150 km/3,200 mi             1,221,860 km/759,300 mi
Hyperion    410x260x220 km/250x155x135 mi 1,481,000 km/920,300 mi
Iapetus     1,460 km/910 mi             3,560,830 km/2,212,900 mi
Phoebe      220 km/135 mi              12,952,000 km/8,048,000 mi


            Diameter                            Distance from Sun

Uranus      51,118 km/31,764 mi       3 billion km/1.8 billion mi

Uranus's Moons:                       Distance from Planet Center

Cordelia    26 km/16 mi                       49,800 km/30,950 mi
Ophelia     30 km/18 mi                       53,800 km/33,400 mi
Bianca      42 km/26 mi                       59,200 km/36,800 mi
Juliet      62 km/38 mi                       61,800 km/38,400 mi
Desdemona   54 km/33 mi                       62,700 km/38,960 mi
Rosalind    84 km/52 mi                       64,400 km/40,000 mi
Portia      108 km/67 mi                      66,100 km/41,100 mi
Cressida    54 km/32 mi                       69,900 km/43,400 mi
Belinda     66 km/40 mi                       75,300 km/46,700 mi
Puck        154 km/95 mi                      86,000 km/53,000 mi
Miranda     472 km/293 mi                    129,900 km/80,650 mi
Ariel       1,158 km/720 mi                 190,900 km/118,835 mi
Umbriel     1,172 km/728 mi                  265,969 km/165,300mi
Titania     1,580 km/981 mi                  436,300 km/271,100mi
Oberon      1,524 km/947 mi                  583,400km/362,500 mi


            Diameter                            Distance from Sun

Neptune     49,528 km/30,776 mi     4.5 billion km/2.7 billion mi

Neptune's Moons:                      Distance from Planet Center

Naiad       54 km/33 mi                       48,000 km/29,827 mi
Thalassa    80 km/50 mi                       50,000 km/31,000 mi
Despina     180 km/110 mi                     52,500 km/32,600 mi
Galatea     150 km/95 mi                      62,000 km/38,525 mi
Larissa     190 km/120 mi                     73,600 km/45,700 mi
Proteus     400 km/250 mi                    117,600 km/73,075 mi
Triton      2,700 km/1,680 mi                354,760km/220,500 mi
Nereid      340km/210 mi                5,509 090 km/3,423,000 mi

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't outlive your money.
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | 
|_____|/  |_|/       |_____|/                     | 

Article: 41508
From: [email protected] (Ron Baalke)
Newsgroups: sci.astro,sci.space
Subject: Re: Happy Birthday Viking I and Voyager II
Date: 20 Aug 1993 16:07 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>,
[email protected] (John McGlaughlin) writes... 

>How long do we estimate we will still have contact with Voyager(s)
>(Knowing we shouldn't have any at this time).  Are the Earth Radio 
>antenna arrays going to arranged to see how long we can keep contact?
 
The Voyager Interstellar Mission is funded through the year 2019.  It
is estimated that the hydrazine fuel won't run out on Voyager 1 until
2040, and 2034 for Voyager 2.  If the funding is there and all we
wanted to do was keep in contact, then this can be done using the
DSN's 70 meter antenna at a downlink telemetry rate of 46.6 bps. One
other fact to consider is that the power level from the RTGs continues
to steadily drop.  Around 2010, the power will have dropped low enough
such that not all of the fields & particles instruments can be turned
on at once.  Around 2019, the power level won't be enough to keep any
of the instruments on. 
 
>Can we only listen or can it ACK a query command?
 
The reception of telemetry if more of a constraint than transmitting
commands to the spacecraft.  The transmitters in the DSN's antenna are
quite powerful. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The hardest thing to learn
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | in life is which bridge to
|_____|/  |_|/       |_____|/                     | cross and which to burn.

 
Excerpted from Jet Propulsion Laboratory UNIVERSE
Pasadena, California - Vol. 23, No. 23 - November 19, 1993
_________________________________________________________________
 
Voyager spacecraft honored for engineering achievements
 
By Mark Whalen
 
JPL's twin-spacecraft Voyager mission--"widely recognized as NASA's most 
successful space program," according to Laboratory Director Dr. Edward 
Stone--was honored Nov. 12 for its unprecedented achievements in 
engineering by the American Society of Mechanical Engineers (ASME). 
 
Voyager 1 and 2, launched in 1977 on a five-year mission to study 
Jupiter, Saturn and their moons, are still active, making their way out 
of the solar system and continuing to far exceed the original mission's 
ambitious goals. 
 
The award represented the 160th Historic Mechanical Engineering Landmark 
to be designated by the ASME since its recognition program began in 1971. 
It was the 40th such designation lauded for its international 
significance. 
 
"It was the project's engineering achievements that made possible the 
science results for which Voyager became world famous," added Stone, who 
is also Voyager's project scientist. 
 
Nick Friesen, a member of ASME's Board of Governors, noted that the 
organization's historic and heritage recognition program "commemorates 
achievements in mankind's dreams, and the Voyagers are fitting (for the 
award), because they are mankind's dreams made real." 
 
The mission "greatly increased public awareness" of science and 
astronomy, he added, also lauding "new values enhanced in American 
industry in Voyager's engineering, ingenuity and resourcefulness." 
 
The 1977 launch was designed to meet a solar-system alignment that occurs 
only once every 176 years. As the mission progressed, additional flybys 
of Uranus and Neptune proved possible. Remote-control programming was 
used to give the two Voyagers greater capabilities than they possessed 
when they left Earth, their two-planet mission extending to four planets. 
 
John Casani, assistant Laboratory director for the Office of Flight 
Projects and a former Voyager project manager, noted that when the 
mission was being contemplated, "the engineering, scientific and 
political communities felt that the challenge to produce a spacecraft 
with an eight- or nine-year life span (for further outer-planet 
exploration) was too daunting. 
 
"But all of us (who worked on Voyager) knew in our hearts that we could 
go to the outer planets." 
 
Casani was joined at the award ceremony by former Voyager project 
managers Harris "Bud" Schurmeier, Ray Heacock, Ek Davis, Richard Laeser 
and Norm Haynes, along with current manager George Textor. Another former 
manager, Robert Parks, was unable to attend. 
 
The Voyagers are continuing to return data about interplanetary space and 
some of Earth's stellar neighbors near the edges of the Milky Way. As the 
spacecraft travel through the solar wind, they are examining the space 
around them with instruments that study fields, particles and waves. 
 
Last May, scientists concluded that the plasma-wave experiment was 
picking up radio emissions that originate at the heliopause--the outer 
edge of our solar system. 
 
Voyager 1 is now rising above the ecliptic plane at an angle of about 35 
degrees and at a speed of about 520 million kilometers (322 million 
miles) a year. Voyager 2 is moving below the ecliptic plane at an angle 
of about 48 degrees and at a speed of about 470 million kilometers (291 
million miles) a year. 
 
Both spacecraft will continue to observe ultraviolet sources among the 
stars, and the fields and particles experiments aboard will allow the 
study of the boundary between the sun's influence and stellar space. 
 
The Voyagers are expected to return valuable data for decades. 
Communications will be maintained until their nuclear-power sources can 
no longer supply enough electrical energy to power-critical subsystems. 

Article: 83458
From: [email protected] (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Voyager I & II - Still communicating?
Date: 25 Feb 1994 17:03 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>,
[email protected] (Darren Arndt) writes... 

>When Voyager II passed Neptune in 1989, I remember hearing that 
>communications would be maintained with it for a few more years.  Is that 
>still happening?  Same question applies to Voyager I as well.  Anything 
>interesting found?  (i.e. asteroids, comets, or info on the heliopause?)
 
We are in contact with Voyager 1 and 2 on a near daily basis.  Both
spacecraft are still sending back data.  In 1990, Voyager 1 took the
family portrait image of the solar system.  Last year, Voyager indirectly 
detected the heliopause boundary, but have not reached it yet. 
 
>In 1989, Voyager II's batteries were getting low.  Are they still able to 
>get a strong enough signal back to earth?  More importantly, back on earth, 
>is there enough budget money for someone to keep tabs on these space 
>explorers?
 
Voyager is powered by RTGs, which slowly decreaes in power over time.
The Voyager mission is funded through 2019.  Ironically, Voyager's
signal is stronger than Galileo's signal.  A couple of weeks ago, we
tested a prototype of our FSR system which will be used to record
Galileo's signal at Jupiter.  We wanted to test it first with a deep
space spacecraft that had a "strong" signal, and Voyager 1 and 2 were
the only ones available.  So we ran out tests with Voyager and
successfully acquired and recorded its signal with our new system. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   Galileo S-Band     | Failure is success if we
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | learn from it.
|_____|/  |_|/       |_____|/                     |             Malcom Forbes

Article: 83699
From: [email protected] (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Voyager I & II - Still communicating?
Date: 2 Mar 1994 18:47 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>, [email protected] writes...

>Were the Voyagers launched with the expectations that the RIG's would last
>~2020 ?? As I recall during the Neptune flyby, the press reported that the 
>power sources have outlasted everybody's expectations.
 
There was actually very little concern about a total failure of the
RTGs.  The power output from the RTGs slowly decrease with time as
the plutonium decays.  At launch in 1977, Voyager had 475 watts of
power, and Voyager 2 at Neptune (1989) had 370 watts.  As of last
week, the RTGs from Voyager 1 and 2 were putting out 351 and 352
watts, respectively. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   Galileo S-Band     | Failure is success if we
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | learn from it.
|_____|/  |_|/       |_____|/                     |             Malcom Forbes

Article: 83701
From: [email protected] (Ron Baalke)
Newsgroups: sci.space
Subject: Re: Voyager I & II - Still communicating?
Date: 2 Mar 1994 18:55 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>,
[email protected] (Stanley J. Sramek) writes... 

>[previous material deleted]
> 
>After Voyager passed Neptune, would it have been possible to point its
>camera back toward Earth and take a picture of Earth as seen from that
>distance? (I know that the image would only have been a point of light;
>that's the whole purpose of suggesting making such an image.)
> 
>Could it still be done, at Voyagers' present distances from Earth? It
>would be really neat to see an image on which the entire Earth is reduced
>to just a tiny, blurred speck of light! Mind-boggling!
 
Voyager 1 is in a better position to take such an image, and did so on
February 14, 1990 when it was 32 degrees above the eclipitic plane and
3.7 billion miles from Earth.  The camera was panned across the solar
system and 64 images were taken of the Sun and each planet.  Venus,
Earth, Jupiter, Saturn, Uranus, and Neptune came out as small dots. 
The image of Mercury was washed out because it was too close to the
Sun, and Mars and Pluto were too small to show up. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   Galileo S-Band     | Failure is success if we
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | learn from it.
|_____|/  |_|/       |_____|/                     |             Malcom Forbes

Article: 83718
Newsgroups: sci.space
From: [email protected] (Henry Spencer)
Subject: Re: Voyager I & II - Still communicating?
Date: Wed, 2 Mar 1994 22:26:45 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]>
[email protected] (Ron Baalke) writes: 

>The power output from the RTG's slowly decrease with time as the 
>plutonium decays...
 
However, if you do the arithmetic using the known half-life of Pu238,
the numbers don't match up.  The Voyager RTGs are losing power faster
than the plutonium is decaying -- substantially faster. 
 
The missing fact is that the radiation also slowly rots the
semiconductor thermoelectric conversion elements.  Their deterioration
appears to be a larger issue than the decay of the plutonium. 
-- 
Belief is no substitute                 | Henry Spencer @ U of Toronto Zoology
for arithmetic.                         |  [email protected]  utzoo!henry

    "Of all noises, I think music is the least disagreeable." - Samuel Johnson
 
    "Impiety:  Your irreverence toward my deity." - Ambrose Bierce
 

Article: 83862
From: [email protected] (Ron Baalke)
Newsgroups: sci.space.tech,sci.space
Subject: Re: Voyager I & II - Still communicating?
Date: 5 Mar 1994 04:59 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]> [email protected] writes:

>Were the Voyagers launched with the expectations that the RIG's would last
>'til ~2020 ?? As I recall during the Neptune flyby, the press reported
>that the power sources have outlasted everybody's expectations.
>Is this a case of the typical media twist on the real story, or is it that the
>JPL team has optimized spacecraft power consumption thus enabling such an 
>extended life ??
 
The Voyagers were designed for a 4 year mission, and they've lasted 17
years and counting.  As the RTGs drop in power, some subsystems will
have to be turned off.  There is enough power for the Ultraviolet UVS
instrument until the year 2000 (its was turned off a year ago due to
lack of funding).  All of the other fields and particles instruments
should have enough power until around 2010.  After that, a power
sharing plan goes into effect, where some of the instruments are
alternately turned on/off, but not all of them are on at the same time. 
 
In article <[email protected]>, [email protected] (Henry
Spencer) writes... 

>The isotope generators' output at any given time is not affected by
>previous economizing; their output at any given time is fixed, and any
>that is not used is wasted.  I don't think JPL has yet had to exercise
>any major cleverness to keep demand within supply.
 
Actually, the computer's fault protection algorithm takes the RTG
output under consideration.  A safety margin of 12 watts was preferred
during an encounter.  If for some reason the spacecraft tries to draw
more power than is available, the onboard computer will automatically
turn off a subsystem to reduce the power consumption.  It just so
happened that this particular scenario never got exercised. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   Galileo S-Band     | A mind stretched by a new
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | idea can never go back to
|_____|/  |_|/       |_____|/                     | its original dimensions.

Article: 83881
From: [email protected] (Ron Baalke)
Newsgroups: sci.space,sci.astro,alt.sci.planetary
Subject: Voyager Spacecraft Honored for Engineering Achievements
Date: 5 Mar 1994 21:39 UT
Organization: Jet Propulsion Laboratory
 
From the "JPL Universe"
November 19, 1993
 
Voyager spacecraft honored for engineering achievements
By Mark Whalen
 
     JPL's twin-spacecraft Voyager mission--"widely recognized as
NASA's most successful space program," according to Laboratory
Director Dr. Edward Stone--was honored Nov. 12 for its
unprecedented achievements in engineering by the American Society
of Mechanical Engineers (ASME).

     Voyager 1 and 2, launched in 1977 on a five-year mission to
study Jupiter, Saturn and their moons, are still active, making
their way out of the solar system and continuing to far exceed
the original mission's ambitious goals.

     The award represented the 160th Historic Mechanical
Engineering Landmark to be designated by the ASME since its
recognition program began in 1971. It was the 40th such
designation lauded for its international significance.

     "It was the project's engineering achievements that made
possible the science results for which Voyager became world
famous," added Stone, who is also Voyager's project scientist.

     Nick Friesen, a member of ASME's Board of Governors, noted
that the organization's historic and heritage recognition program
"commemorates achievements in mankind's dreams, and the Voyagers
are fitting (for the award), because they are mankind's dreams
made real."

     The mission "greatly increased public awareness" of science
and astronomy, he added, also lauding "new values enhanced in
American industry in Voyager's engineering, ingenuity and
resourcefulness."

     The 1977 launch was designed to meet a solar-system
alignment that occurs only once every 176 years. As the mission
progressed, additional flybys of Uranus and Neptune proved
possible. Remote-control programming was used to give the two
Voyagers greater capabilities than they possessed when they left
Earth, their two-planet mission extending to four planets.

     John Casani, assistant Laboratory director for the Office of
Flight Projects and a former Voyager project manager, noted that
when the mission was being contemplated, "the engineering,
scientific and political communities felt that the challenge to
produce a spacecraft with an eight- or nine-year life span (for
further outer-planet exploration) was too daunting.

     "But all of us (who worked on Voyager) knew in our hearts
that we could go to the outer planets."

     Casani was joined at the award ceremony by former Voyager
project managers Harris "Bud" Schurmeier, Ray Heacock, Ek Davis,
Richard Laeser and Norm Haynes, along with current manager George
Textor. Another former manager, Robert Parks, was unable to attend.

     The Voyagers are continuing to return data about
interplanetary space and some of Earth's stellar neighbors near
the edges of the Milky Way. As the spacecraft travel through the
solar wind, they are examining the space around them with
instruments that study fields, particles and waves.

     Last May, scientists concluded that the plasma-wave
experiment was picking up radio emissions that originate at the
heliopause--the outer edge of our solar system.

     Voyager 1 is now rising above the ecliptic plane at an angle
of about 35 degrees and at a speed of about 520 million
kilometers (322 million miles) a year. Voyager 2 is moving below
the ecliptic plane at an angle of about 48 degrees and at a speed
of about 470 million kilometers (291 million miles) a year.

     Both spacecraft will continue to observe ultraviolet sources
among the stars, and the fields and particles experiments aboard
will allow the study of the boundary between the sun's influence
and stellar space.

     The Voyagers are expected to return valuable data for
decades. Communications will be maintained until their
nuclear-power sources can no longer supply enough electrical
energy to power-critical subsystems.
 
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab | 
 ___| | | | |__) |/  | | |__   Galileo S-Band     | A mind stretched by a new
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | idea can never go back to
|_____|/  |_|/       |_____|/                     | its original dimensions.

Article: 1170
From: [email protected] (Dick Buenneke)
Newsgroups: sci.space.tech
Subject: Re: music on Voyager
Date: Sun, 20 Mar 1994 15:40:56 -0800
Organization: RAND -- Santa Monica, Calif.
 
In article <[email protected]>,
[email protected] (Alan Anderson) wrote:
 
> There is a CD called (I think) "Murmurs of Earth" available from (I think) 
> The Planetary Society.  It might be a CD-ROM with the pictures also.
 
There is also a book with the same title by Carl Sagan and others. Below is
the full reference.  I think this will give you what you're looking for.
 
Title:         Murmurs of Earth: The Voyager Interstellar Record / Carl Sagan
                 ... [et al.]. 1st Ballantine Books ed. New York :
                  Ballantine Books, 1979, c1978.
Description:   273 p., [8] p. of plates : ill. (some col.) ; 26 cm.
 
Notes:         Reprint of the ed. published by Random House, New York.
               Includes index.
               Discography: p. 204-205.
               Bibliography: p. 205-209.
               Contents:  Sagan, C. For future times and beings.--Drake, F. D.
                 The foundations of the Voyager record.--Lomberg, J.
                 Pictures of Earth.--Sagan, L. S. 
                 A Voyager's greetings.--Druyan, A.
                 The sounds of Earth.--Ferris, T. Voyager's music.--Sagan, C.
                 The Voyager mission to the outer solar system.--Sagan, C.
                 Epilogue.
   
> I don't have any idea who chose the contents of the recording.

I believe it was Sagan and the others listed above.
 
-- 
Richard H. Buenneke Jr.                     Tel: (310) 393-0411, Ext. 7382 
RAND Graduate School                        Fax: (310) 393-4818
1700 Main Street                              Internet: [email protected]
P.O. Box 2138                                   "All opinions are mine alone,
Santa Monica, Calif.  90407-2138        All facts speak for themselves"

From:	US4RMC::"[email protected]" "Peter Yee"  3-JUN-1994 21:02:13.11
To:	[email protected]
CC:	
Subj:	Voyager Status for 06/03/94 (Forwarded)

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

                      VOYAGER STATUS REPORT
                           June 3, 1994

     Both the Voyager 1 and 2 spacecraft are healthy as they head
out of the solar system, continuing to collect data on fields and
particles in their quest to detect the heliopause -- the outer
boundary of the sun's energy influence.

     In addition, both spacecraft are using their ultraviolet
spectrometers to look back at the sun and study solar activities. 
Voyager 2 will use its ultraviolet spectrometer and the planetary
radio astronomy experiment to observe the impact of comet
Shoemaker-Levy-9 with Jupiter in July.

     As of June 1, Voyager 1 was 8.2 billion kilometers (5.1
million miles) from Earth and Voyager 2 was 6.3 billion
kilometers (3.9 billion miles) from Earth.

From:	US4RMC::"[email protected]" "MAIL-11 Daemon" 30-JUN-1994 
To:	[email protected]
CC:	
Subj:	Voyager 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

                      VOYAGER STATUS REPORT
                          July 1, 1994

     Both the Voyager 1 and 2 spacecraft are healthy and they
continue to collect fields and particles data in their quests to
detect the heliopause, the outer edge of the Sun's energy influence.

        In addition, both spacecraft are using the ultraviolet
spectrometers to look back at our Sun and study solar activities.
Voyager 2 will use its ultraviolet spectrometer and the planetary
radio astronomy experiment to observe the impact of comet
Shoemaker-Levy 9 with Jupiter later this month.

     As of  July 1, Voyager 1 was 8.3 billion kilometers (5.1
billion miles) from Earth and Voyager 2 was 6.4 billion
kilometers (3.9 billion miles) from Earth.  Voyager 1 is
traveling at an average heliocentric velocity of 39,200 miles per
hour and Voyager 2 is traveling at 36,200 miles per hour.

From:	US4RMC::"[email protected]" "MAIL-11 Daemon" 30-JUL-1994 
To:	[email protected]
CC:	
Subj:	Voyager status 8/1/94

PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

                       VOYAGER MISSION STATUS
                           August 1, 1994

     Both the Voyager 1 and 2 spacecraft are healthy and they are
continuing to take data on fields and particles in interplanetary space. 

     The Voyager 2 spacecraft used two of its scientific instruments
to look at the impacts of Comet Shoemaker-Levy 9 fragments as they
impacted Jupiter July 16-22.  Both the ultraviolet spectrometer and
the planetary radio astronomy experiments were used in the
observations.  Neither instrument detected any UV emission or radio
signals during the impacts.  The spacecraft began its observations of
Jupiter on July 8 and will continue to observe the planet until August
17.  At the time of the comet impacts, Voyager 2 was 6.1 billion
kilometers (3.7 billion miles) from Jupiter. 

     Voyager 1 is currently 8.4 billion kilometers (5.2 billion miles)
from Earth.  Voyager 2 is 6.4 billion kilometers (4 billion miles)
from Earth. 

                             #####

Article: 6334
From: [email protected]
Newsgroups: sci.space.news
Subject: Voyager status 9/1/94
Date: 1 Sep 1994 10:57:14 -0700
Organization: Jet Propulsion Laboratory - Pasadena CA
Sender: [email protected]
 
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
 
                        VOYAGER MISSION STATUS
                          September 1, 1994
 
     Both Voyager spacecraft are healthy and are continuing their fields 
and particles experiments as they cruise through interplanetary space. 
 
     Flight controllers believe both spacecraft will continue to
operate and send back valuable data until at least the year 2015.  It
is the loss of electrical power from their radioisotope thermoelectric
generators (RTGs) that will eventually cause them to stop functioning.
At launch, the three RTGs on each spacecraft had a power output of
475 watts.  Today, that output is 348 watts for Voyager 1 and 351
watts for Voyager 2.   The science experiments need between 210 and
220 watts to operate. 
 
     The other vital consumable onboard the spacecraft is the amount
of hydrazine propellant which keeps the Voyagers stable and pointed
toward Earth.  Each spacecraft started out with 104 kilograms of
propellant.  Today, after 17 years on the job and multiple encounters
and trajectory correction maneuvers, Voyager 1 is down to 34.8
kilograms and Voyager 2 is at 37.3 kilograms.  However, during its
current interstellar mission, each spacecraft uses only about six
grams of fuel a week.  Flight controllers stress the Voyagers will run
out of electrical power long before they start spinning out of control
due to loss of their attitude-adjusting propellant. 
 
     Both Voyagers continue to be tracked every day by the large
antennas of the Deep Space Network.  Voyager 1 receives about 120
hours of tracking time each week, while Voyager 2 receives about 90
hours a week.  Voyager 2 is tracked less because it shares the
resources of the DSN station in Canberra, Australia, with NASA's
Galileo spacecraft.  The Canberra station has the best "look angle"
for both Voyager 2 and Galileo. 
 
     It is now estimated that Voyager 1 will pass the Pioneer 10
spacecraft in January 1998 to become the most distant human-made
object in space. 
 
     Voyager 1 is approximately 8.5 billion kilometers (5.3 billion
miles) from Earth, while Voyager 2 is 6.5 billion kilometers (4
billion miles) from home. 
 

Article: 4257
From: [email protected] (Ron Baalke)
Newsgroups: sci.astro,alt.sci.planetary
Subject: Re: Voyager Update - 09/01/94
Date: 7 Sep 1994 16:02 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>, [email protected] (Jeff
Bulf) writes... 

>In article <[email protected]>
>[email protected] (Ron Baalke) writes:
>>     Flight controllers believe both spacecraft will continue to
>>operate and send back valuable data until at least the year 2015.
>>It is the loss of electrical power from their radioisotope
>>thermoelectric generators (RTGs) that will eventually cause them
>>to stop functioning.  At launch, the three RTGs on each
> 
>A question...
>Some years ago, I read that contact with the spacecraft will probably be
>lost before either elctrical power or propellant runs out.  The reason:
>as distance from the Sun increases, it becomes more difficult for the
>spacecraft's on-board sensors to distinguish the Sun from other bright stars.
>When the Sun cannot be distinguished reliably, the high-gain antenna can
>no longer be aimed toward Earth.
> 
>Does anybody know whether this scenario is still considered likely,
>or is RTG run-down now expected to predominate?
 
Voyager uses a star tracker and a sun sensor to maintain its fixed
attitude.  I haven't heard that the increasing distance will be a
problem for the sun sensor.  In fact, I've heard that the DSN would be
able to maintain contact with both spacecraft until 2037 provided the
spacecraft are able to survive that long.  Propellant isn't a problem
either - Voyager 1 isn't expected to deplete its hydrazine until 2040
and Voyager 2 has until 2034.  The limiting factor is the RTG's. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke     | [email protected]
     | | | |  __ \ /| | | |     JPL/Telos      | 
  ___| | | | |__) |/  | | |__   Galileo S-Band | If you don't know where you're
 /___| | | |  ___/    | |/__ /| Pasadena, CA   | going, you'll end up somewhere
 |_____|/  |_|/       |_____|/                 | else.   Yogi Berra.

Article: 4259
Newsgroups: sci.astro,alt.sci.planetary
From: [email protected] (Dave Tholen)
Subject: Re: Voyager Update - 09/01/94
Sender: [email protected]
Organization: Institute for Astronomy, Hawaii
Date: Wed, 7 Sep 1994 08:30:10 GMT
 
Jeff Bulf writes:
 
> Some years ago, I read that contact with the spacecraft will probably be
> lost before either elctrical power or propellant runs out.  The reason:
> as distance from the Sun increases, it becomes more difficult for the
> spacecraft's on-board sensors to distinguish the Sun from other bright stars.
> When the Sun cannot be distinguished reliably, the high-gain antenna can
> no longer be aimed toward Earth.
> 
> Does anybody know whether this scenario is still considered likely,
> or is RTG run-down now expected to predominate?
 
I don't see how this scenario could have ever been considered likely.  The
brightest star in the sky other than the Sun is Sirius, at apparent visual
magnitude -1.5.  The Sun will be a factor of 100 brighter than Sirius as
long as its apparent visual magnitude is brighter than -6.5, which is a
full 20 magnitudes fainter than its apparent visual magnitude as seen from
Earth.  20 magnitudes represents a factor of 100,000,000 in brightness, or
a factor of 10,000 in distance.  That is, the Sun will remain more than a
factor of 100 times brighter than Sirius all the way out to a distance of
10,000 astronomical units.  By the year 2015, the Voyagers may have reached
a distance of perhaps 100 astronomical units (rounded off), and the Sun
will have an apparent visual magnitude of -16, which is brighter than the
full Moon.  Can you imagine having difficulty distinguishing between Sirius
and the full Moon (especially if the latter's light was concentrated into
a much smaller source)?

Article: 4275
From: [email protected] (Ron Baalke)
Newsgroups: sci.astro,alt.sci.planetary
Subject: Re: Voyager Update - 09/01/94
Date: 8 Sep 1994 16:03 UT
Organization: Jet Propulsion Laboratory
 
In article <[email protected]>,
[email protected] (Maurice Leonard Clark) writes... 

>Regarding the updates on various missions, I was just wondering how the
>Pioneer 10 and 11 spacecraft were going. Are the still in contact or was
>contact lost some time back?
 
We are still in contact with both Pioneer 10 and 11.  A Space News article
from about a month ago said the RTG's on the spacecraft are in better
shape than expected, which will extend the lifetimes of their missions.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke     | [email protected]
     | | | |  __ \ /| | | |     JPL/Telos      | 
  ___| | | | |__) |/  | | |__   Galileo S-Band | If you don't know where you're
 /___| | | |  ___/    | |/__ /| Pasadena, CA   | going, you'll end up somewhere
 |_____|/  |_|/       |_____|/                 | else.   Yogi Berra.

Article: 4287
From: [email protected] (Dick Edgar)
Newsgroups: sci.astro,alt.sci.planetary
Subject: Re: Voyager Update - 09/01/94
Date: 9 Sep 1994 16:58:19 GMT
Organization: University of Wisconsin - Astronomy Department
 
In article <[email protected]>
[email protected] (Ron Baalke) writes: 

!In article <[email protected]>, [email protected]
!(Vareck Bostrom) writes... 
!>I know the answer is on the order of hundreds of thousands or millions
!>of years, but how long will it be until Voyager 1 and 2 are closer to
!>another star than they are to the sun? What stars are the Voyagers 
!>going to be flying by in the next 20 million years? Does anyone
!>have a schedule of the interstellar space flight they are going to make?
!> 
!The first star that Vyager 2 will "flyby" is Barnard's Star in the year
!8571, but it will still be 4.03 light years from the star.  The closest
!star that Voyager 2 will be flying near in the next million years is 
!Ross 248 in the year 40,176.  It will only be 1.65 light years from the star
!but 1.99 light years from our Sun. 
 
Umm... excuse me, but are those parsecs?  According to a table of the
nearest stars in Allen's "Astrophysical Quantities," (3rd ed.), the
parallax of Ross 248 is 0.317 arcseconds, so the distance is 1/0.317 =
3.15 parsecs, which is 10.28 lightyears.  Even the nearest star (Proxima
Cen) is more than 1.99 + 1.65 = 3.64 lightyears away... (actual distance
about 1.31 parsecs = 4.28 lightyears, using the same table and calculation).
 
---------
Richard J. Edgar  ([email protected])
University of Wisconsin--Madison, Department of Astronomy

"An astrophysicist is someone who sees something working in practice,
and wonders whether it will work in principle." -- Harvey Liszt

Article: 4288
From: [email protected] (Ron Baalke)
Newsgroups: sci.astro,alt.sci.planetary
Subject: Re: Voyager Update - 09/01/94
Date: 9 Sep 1994 17:45 UT
Organization: Jet Propulsion Laboratory
 
The units I gave are in light years.  Also, the distances I gave are
the distance between the spacecraft and star.  I gave no distances
from our Sun to the star. 

Also taken into account is that over several thousands of year, stars
will moved significent distances relative to each other.  I believe
Allen's "Astrophysical Quantities" only lists the distances as they
are today, not 40,000 years from now.  Here is a list of nearby stars
that Voyager 2 will encounter in the next million years. All distances
are in light years, and star movement is taken into account. 
 
                Year of Closest  Voyager 2 to   Sun to Voyager 2  Sun to Star
Star               Approach      Star Distance  Distance          Distance
---------------------------------------------------------------------------
Barnard's Star      8,571         4.03           0.42             3.80
Proxima Centauri   20,319         3.21           1.00             3.59
Alpha Centauri     20,629         3.47           1.02             3.89
Lalande 21185      23,274         4.65           1.15             4.74
Ross 248           40,176         1.65           1.99             3.26
DM-36 13940        44,492         5.57           2.20             7.39
AC+79 3888         46,330         2.77           2.29             3.76
Ross 154          129,084         5.75           6.39             8.83
DM+15 3364        129,704         3.44           6.42             6.02
Sirius            296,036         4.32          14.64            16.58
DM-5 4426         318,543         3.92          15.76            12.66
44 Ophiuchi       442,385         6.72          21.88            21.55
DM+27 1311        957,963         6.62          47.38            47.59

      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke     | [email protected]
     | | | |  __ \ /| | | |     JPL/Telos      | 
  ___| | | | |__) |/  | | |__   Galileo S-Band | If you don't know where you're
 /___| | | |  ___/    | |/__ /| Pasadena, CA   | going, you'll end up somewhere
 |_____|/  |_|/       |_____|/                 | else.   Yogi Berra.

Article: 4293
From: [email protected] (Ron Baalke)
Newsgroups: sci.astro,alt.sci.planetary
Subject: Re: Voyager Update - 09/01/94
Date: 9 Sep 1994 16:25 UT
Organization: Jet Propulsion Laboratory
 
The first star that Vyager 2 will "flyby" is Barnard's Star in the
year 8571, but it will still be 4.03 light years from the star.  The
closest star that Voyager 2 will be flying near in the next million
years is Ross 248 in the year 40,176.  It will only be 1.65 light
years from the star but 1.99 light years from our Sun. 

      ___    _____     ___
     /_ /|  /____/ \  /_ /|     Ron Baalke     | [email protected]
     | | | |  __ \ /| | | |     JPL/Telos      | 
  ___| | | | |__) |/  | | |__   Galileo S-Band | If you don't know where you're
 /___| | | |  ___/    | |/__ /| Pasadena, CA   | going, you'll end up somewhere
 |_____|/  |_|/       |_____|/                 | else.   Yogi Berra.

Article: 4309
Newsgroups: sci.astro,alt.sci.planetary
From: [email protected] (Henry Spencer)
Subject: Re: Voyager Update - 09/01/94
Date: Sat, 10 Sep 1994 19:43:47 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]> [email protected]
(Dick Edgar) writes: 

>!Ross 248 in the year 40,176.  It will only be 1.65 light years from the star
>!but 1.99 light years from our Sun. 
>
>Umm... excuse me, but are those parsecs?  According to a table of the
>nearest stars in Allen's "Astrophysical Quantities," (3rd ed.), the
>parallax of Ross 248 is 0.317 arcseconds, so the distance is 1/0.317 =
>3.15 parsecs, which is 10.28 lightyears...
 
That's the distance *today*.  40kY from now, it will have changed.  Closing
by about seven lightyears in 40kY requires a radial relative motion of only
about 50km/s.  That's well within the realm of possibility.
-- 
"It was blasphemy that made us free."              |       Henry Spencer
                        -- Leon Wieseltler         |   [email protected]

Article: 4290
From: [email protected] (Roy Owens)
Newsgroups: alt.sci.planetary
Subject: Pioneer 10 and 11
Date: 9 Sep 1994 19:57:36 GMT
Organization: Jet Propulsion Laboratory, Pasadena
Sender: -Not-Authenticated-[8419]
 
Pioneers 10 and 11 are regularly tracked. Earlier today (Friday UTC)
station 63 tracked Pioneer 10 (day 252) from 0017-0502, and the day
before (251) tracked Pioneer 11 (1927-0000).

Article: 6503
From: [email protected]
Newsgroups: sci.space.news
Subject: Voyager status 10/1/94
Date: 30 Sep 1994 20:56:42 -0700
Organization: Jet Propulsion Laboratory - Pasadena CA
Sender: [email protected]
 
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
 
                     VOYAGER MISSION STATUS
                        October 1, 1994
 
     Both Voyager spacecraft are in good health and collecting
ultraviolet data and studying fields, particles and waves in the
outer solar system as they search for the heliopause -- the end
of the sun's influence in space -- and the associated termination
shock.
 
     Voyager 1 is 8.5 billion kilometers (5.3 billion miles) from
the sun, traveling at a speed of 17.5 kilometers per second
(39,146 miles per hour).
 
     Voyager 2 is 6.6 billion kilometers (4 billion miles) from
the sun, traveling art a speed of 16.2 kilometers per second
(36,238 miles per hour).
 
                               #####

Article: 6898
From: [email protected] (Ron Baalke)
Newsgroups: sci.space.news
Subject: Voyager Update - 02/01/95
Date: 10 Feb 1995 17:30:31 -0800
Organization: Jet Propulsion Laboratory
Sender: [email protected]
 
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
 
                        Voyager Status Report
                           February 1, 1995
 
     Both spacecraft are healthy and are continuing to make 
observations of  their interplanetary environment.  They are using 
their ultraviolet spectrometers to map the heliosphere and study 
the incoming interstellar wind.  The cosmic ray detectors are 
seeing the energy spectra of interstellar cosmic rays in the outer 
heliosphere.  The magnetometer sensors are still measuring the 
strength and direction of the solar magnetic field.  The plasma 
detectors looking back at the Sun record the solar wind 
parameters.  The low energy charged particle experiment studies 
the energy spectra of particles coming from the Sun.  The plasma 
wave instrument is studying the incoming signals from the 
direction of the heliosphere.
 
Voyager 1 is currently 8.8 billion kilometers (5.5 billion miles) 
from Earth and is traveling at a speed of  61,200 kilometers per 
hour (39,000 miles per hour).  Voyager 2 is 6.8 billion kilometers 
(4.3 billion miles) from Earth and is traveling at a speed of  
57,600 kilometers per hour (36,000 miles per hour).
 
                                 #####