Conference 7.286::space

    According to Aviation Week, both the Galileo and also the Ulysses
    missions have been postponed until the next Jupiter launch window
    (at the earliest) which I think is about 13 months from the May
    window.  NASA has given the go-ahead to have Discovery outfitted
    to carry the Centaur upper stage since, as noted, the only two orbiters
    with that capability were the Atlantis and the Challenger.  Also
    as noted, if both missions are to fly within the same launch window
    then two orbiters must be capable of carrying the Centaur, since
    a turn-around of the same orbiter for two flights within a three-week
    period is unlikely.
    
    There is currently a lot of discussion about using the shuttle for
    these two missions because of risks involved.  The Galileo uses
    a nuclear power plant containing plutonium.  I'm not sure how the
    Ulysses is powered.  The prospect of plutonium being involved in
    an accident similar to Challenger's is unsettling at best.
    Furthermore, the Centaur payload shifts the center-of-gravity of
    the orbiter forward, making an RTLS (return to launch site) abort
    impossible without lightening the fuel load.  Recall that Columbia's
    last flight was specially instrumented, in part to determine what
    happens when the forward RCS rockets are fired within the atmosphere.
    Firing these is the plan used to burn fuel and shift the center
    of gravity back if an rtls abort is required during a Centuar launch,
    enabling the orbiter to land safely at the Cape.  This all seems
    like a fragile chain of events to me, considering that some dire
    event would have caused an rtls abort in the first place, and the
    orbiter would be trying to land under diminished capacity in an
    un-tried abort mode.  There's also safety questions about the Centaur
    itself, which utilizes liquid oxygen and hydrogen, and we've all
    seen how quickly these can explode.
    
    One effect of the Challenger event will hopefully be a re-evaluation
    of expendable boosters for payloads which don't require manned
    intervention or for particularly dangerous payloads (among which
    I would place the Centaur).  While I support manned spaceflight
    and appreciate its merits, I now believe we need an unmanned capability
    for some payloads.  This will probably be one side effect of the
    Challenger event.  I also wish NASA would re-consider flying the
    Centaur on the shuttle.
    
    Another side effect is the delay of the Hubble space telescope (as
    well as all other payloads currently scheduled).  The space telescope
    has incredible potential for pure astronomical research since it
    will fly above the Earth's atmosphere.  Great discoveries await
    us, but they will be delayed until the shuttle flies again.
    
    I'm sure the list goes on.
    

Subj: Workload for the remaining shuttles
Newsgroups: net.space
Path: decwrl!ucbvax!space
Posted: 24 Feb 86 19:00:00 GMT
Organization: The ARPA Internet
 
 
According to an article in this morning's Los Angeles Times, intensive
studies by NASA, DoD, and the NSC have found that the loss of Challenger
will severely handicap the nation's space program for years to come due
to the cutback in payload capacity.  National security requirements for
placing military payloads in orbit will likely consume more than 75%
of the capacity of the three remaining shuttles for the next five years,
leading to a cutback of more than 50% in scientific and commercial
payload space, and the likely mothballing of payloads that have
taken years to develop.

    I saw this in net.space, and find the 75% figure hard to believe.
    75% of 3 vehicles is 56.25% of 4 vehicles.  I don't believe that
    more than � of the launch capability was taken up by the military
    before the accident.
    
    This is not to say that I don't believe there is a serious problem with
    launch capacity...
    
    Burns

A kind of "devil's advocate" question:

	"Is there any reason not to resume shuttle flights ASAP?"

It would seem from the presidential investigation so far that:

	1) the SRB's were far below their temperature limit at points on
	their exterior -- enough of a reason to cause the joint failure,
	and totally avoidable,

	2) while the SRB joint design is a weak link, it is a link that
	has a backup (the second O-ring) that never failed (when used
	within the design temperature range) even in the cases that a
	primary ring eroded (and it's not clear that "eroded" is 
	equivalent to complete failure of the primary ring).

Added arguments for resuming flights ASAP:

	1) national security requires it,

	2) a delay at this point only further aggravates the scheduling
	impact of the loss of Challenger,

	3) a substitute unmanned launch system will take at least as long
	to develop as the some of the estimated delays till the resumption
	of launches,

	4) added delay is unlikely to reveal new information on the exact
	cause of the accident.  About the only thing that could help
	this is recovery of the SRB case, and even that would help only if
	the right parts are recovered.  And even the presidential commission
	is due to issue its reports before the SRB cases are likely to
	be recovered,

	5) carefully monitored and instrumented flights could add a lot
	of information to the investigation and solution -- much more
	so than even static tests.

Rebuttal?

Bob

    	I also see no reason that launches with minimal crew should
    not be restarted as soon as possible for the same reason as .3.
    	If weather temp is such a problem why couldn't a large movable
    heated hanger be built to drive over the shuttle on in place on
    the pad and then be driven off a couple of hours before the launch
    when the temperature has at least reached the minimal design 
    criterea?
    	Any answers?
    	One last thought. Regardless of how it gets there,if anything
    happens to the Hubble telescope I think it would be a devastating
    blow to science in general. I can think of no other cargo loss ,with
    the exception of human life, that would be more devastating to our
    persuit of knowledge.
    
    Gold::Gallant/Mike
    

re .5:

>    	If weather temp is such a problem why couldn't a large movable
>    heated hanger be built to drive over the shuttle on in place on
>    the pad and then be driven off a couple of hours before the launch
>    when the temperature has at least reached the minimal design 
>    criteria?


Remember that Florida is usually quite warm.  And even such a device would
take time to build and have its hazards, e.g., a potential for concentrating
spilled gasses/vapors.

Actually, the next flight cluster is already (partially?) assembled in the VAB.
Would there be any benefit in dismantling it to check the seals? What were some
of the rejected solutions for improving the seals -- are any of them easy to
implement?  Do they supplement rather than replace the current seals (my
reasoning is that supplementary changes have a lower probability of introducing
new problems since they keep the usually successful current seals as one of the
lines of defense). 

Bob

re .5:

>    	If weather temp is such a problem why couldn't a large movable
>    heated hanger be built to drive over the shuttle on in place on
>    the pad and then be driven off a couple of hours before the launch
>    when the temperature has at least reached the minimal design 
>    criteria?

This was already discussed elsewhere in this file: a structure has been
designed which shields the ET and SRB's from cold winds, with a pair of jet
engines as an extra heat source.  It is in place at Vandenberg, but a
decision was made not to build one at KSC because there are so few cold days
there.

In regards to the other issue, I would suspect they would not want to have
any more launches, even with only a minimal number of professional astronauts
at risk, until they are 100% sure of the cause of the Challenger tragedy.
In addition to risking the lives of the crew, they would also be risking the
loss of one-third of the remaining shuttles, the launch facility, and the
lives of launch facility personnel (e.g., rescue tank drivers).  The shuttle
program is already set back rather badly; the loss of any of the above would
wreak so much additional havoc upon the program as to not make it worth the
risk.

    Re .5:  I think there are still significant unanswered questions.
    While it seems quite clear that the right SRB leaked, that is not
    the same as finding the cause.  Were the seals bad because of temp?
    If so was it the ambient temp, or was there an ET leak?  Did the
    SRB REALLY leak at the seal or was it elsewhere?  What is this bull
    about the secondary seal not really being trustworthy at all times?
    Were we just lucky that this kind of thing did not happen before?
    Etc etc etc.
    
    Not to mention the political problems.  You think NASA is in trouble
    now, just imagine what would happen if they launched again and it
    blew up again!  (Obviously there are other reasons why it would
    not be good to have another explosion...I am just mentioning the
    less obvious one)
    
    Burns
    

re .7:

>This was already discussed elsewhere in this file: a structure has been
>designed which shields the ET and SRB's from cold winds, with a pair of jet
>engines as an extra heat source.  It is in place at Vandenberg, but a
>decision was made not to build one at KSC because there are so few cold days
>there.

(More and more I think that the word "tragedy" really does apply here.  If
cold is considered to be so critical that special precautions are taken
at Vandenburg (a not particularly cold place), then why did NASA officials
even seriously consider launching on the coldest morning of the year?)


>In regards to the other issue, I would suspect they would not want to have
>any more launches, even with only a minimal number of professional astronauts
>at risk, until they are 100% sure of the cause of the Challenger tragedy.

There is a very real possibility that they will never be 100% sure of
the cause of the accident.  They certainly won't be so sure unless the right
SRB is recovered, and even in that case "100% assurance" may not be achieved.
The criterion has to be something like "100% sure or some certain amount
of effort has been spent in trying to find the cause".  What should that
"certain amount" be?

Bob

    We have a harsh reality that we (ie: everybody) have to face.
    The problem will not be 100% determined.  To think that that is
    possible is fool-hardy.
    
    The shuttle will not be 100% safe.  To think this so is fool-hardy.  A
    second shuttle accident is possible, regardless of what is found
    and what is done to correct it.  While the possibility may be low,
    it will never be zero.
    
    It's hard to express my feelings of late with some of the talk that
    I have been hearing.  (Not from this conference.)  It seems so
    negative.  I've heard people say 'It shouldn't have been launched'
    so many times I think I'll scream!  Of course the Challenger '7'
    shouldn't have died!  Neither should Kennedy have been killed!
    Say it, get it out of your system, and lets get back to it.
    
    Anyway, I'll calm down now...
    

re .-1 & .-2

Although I said "100%", what I meant "as certain as possible".  Having a
background in fault-tolerant computers, I certainly do know better, but my
verbal laziness sometimes comes to the fore.

    re .4, .5 and some others:
    
    I suspect that the Astronauts (note statements by Young and Ride)
    will have some say on when the next flight takes place.  I also
    suspect that they are probably the best people to decide in many
    respects: they want the program to continue, they are willing to
    take risks, they don't want to fly under unsafe conditions, they
    understand the issues.
    
    						Mike
    
    (PS.  It appears that the Astronauts have not always been aware
    of all the issues surrounding the Shuttle's potential problems nor
    the apparent shift in NASA management focus.  If they had I don't
    think we would be discussing the loss of 51-L and the subsequent
    affects on the program.  Lower flame...I have been a fan/advocate
    of the space program since I was a kid and hate to see it stalled
    over something that seems to have been easily avoided.)