[net.columbia] RMS Attempt to be Made

alb@alice.UUCP (Adam L. Buchsbaum) (04/09/84)

Grond controllers at the Goddard Space Center succeeded
over the night in stabilizing the SMM satellite to some 
extent, bringing its momentum into the range that a body
can have if the RMS system is to safely grab it.  They
also were able to reorient its solar panels, so the satellite
is out of danger from failing batteries.  NASA then decided
that an attempt to snare the satellite directly with the
remote arm will be made, either Monday or Tuesday.  A
failure to grab it would mean a one-day curtailment of the
mission; a success would mean a one-day extension.

wmartin@brl-vgr.ARPA (Will Martin ) (04/09/84)

I managed to catch the initial failing attempts to de-spin Solar Max
via network news coverage (NBC) Sunday morning, but they (of course)
neglected to answer the obvious questions that came to mind:

1) Can the MMU be re-fueled for re-use while the shuttle is in orbit?
I would think that this would be vitally necessary for any practical
use of such a system. If it can, why didn't they just say that they
would re-fuel it after it red-lined?

2) I was surprised that Pinky grabbed on the outer edge of the solar
cell array to apply thrust to slow Solar Max's spin. Didn't that
strain the panel attachment? It wasn't designed to do more than hold
the panel, was it? Was the force applied to this joint within design
specs or was this a calculated risk?

As of this writing, I haven't heard or seen any later developments,
except that they planned to to use the arm while Max still spun.
Has the reason for the failure of the suit-attachment unit been
announced yet? 

Will

alb@alice.UUCP (Adam L. Buchsbaum) (04/10/84)

Yes, the MMU can be refueled in orbit in 20 minutes.
There is also a spare MMU, already fueled, on board.
The reason another attempt was not made was due to
a shortage of maneuvering propellant on the shuttle itself.

brahms@trwspp.UUCP (04/10/84)

[}{]
> 1) Can the MMU be re-fueld for re-use while the shuttle is in orbit?

	Yes, it can and will be.

> 2) I was surprised that Pinky grabbed on the outer edge of the solar
> cell array to abbly thrust to slow Solar Max's spin.  Didn't that
> strain the panel attachment?  It wasn't designed to do more than hold
> the panel, was it?  Was the force applied to this joint within design
> specs or was this a calculated risk.

	This option was discussed during pre-flight.  It was an option
that would be left up to the astronauts to decide.  Oh, and as you can
see, it could handle the additonal stress.  I'm not sure, however, if it
is was a design issue or not.  However, NASA being the way they are, I doubt
that they would do something that had a chance a breaking something.

			-- Brad Brahms
			   usenet: {decvax,ucbvax}!trwrb!trwspp!brahms
			   arpa:   Brahms@USC-ECLC

rjnoe@ihlts.UUCP (Roger Noe) (04/10/84)

I, too, was surprised that Nelson (I cannot seem to bring myself to call him
Pinky) grabbed the solar panel at Crippen's insistence.  I was watching it live
and I was thinking out loud at the time that he would impart an off-axis torque
to SMM by so doing.  This appears to be what happened.  I would think that the
trunnion pin itself would be much closer to the center of mass and would be a
better place to grab both in terms of torque and stress considerations.  But
then I wasn't up there and it's not my place to second-guess the professionals
in space and on the ground.

At first I also thought that the low fuel remarks referred to the MMU N2
propellant but later realized that it was the silly network people who were
misleading me.  (Lynn Sherr is rapidly becoming one of my least favorite
network TV personalities.)  Of *course* they can recharge the MMU's in under
half an hour, but the OMS cannot be recharged and they still need it for a
number of things before (and including) deorbit.

I'm happy about the successful grab Terry Hart made with the RMS, but if they
could slow down SMM from the beginning, why did they REALLY need the MMU's?
Of course, we can all thank ILC Space Systems for their ultra-reliable TPAD
(trunnion pin attachment device) :-) .  Actually, it not only worked perfectly
last shuttle mission, it tested out fine in the payload bay both before and
after Nelson made his unsuccessful EVA (so I've heard).  Good old Murphy!
I can't wait for the next Aviation Week & Space Technology.
--
	Roger Noe		ihnp4!ihlts!rjnoe

smb@ulysses.UUCP (Steven Bellovin) (04/11/84)

Speaking of TV idiots -- to my mind the best launch coverage I've seen
from them was the one at 3:00 am.  Whoever was covering it for NBC just
*shut up* and let Mission Control and the astronauts do the talking.
That was the only launch I didn't listen to on 900-410-6272.

jlg@lanl-a.UUCP (04/11/84)

malfunctioning) docking device.  From the pictures I saw, it should have been
simple to put a sling or rope around the body of the satellite, tighten it up 
and hold on to that in order to supply the torque needed to despin.  I can't
imagine that the cladding of the satellite would be so weak that it couldn't 
handle the pressure of a wide strap of nylon webbing or something.  Is this 
just an example of expensive solutions to simple problems?

alb@alice.UUCP (Adam L. Buchsbaum) (04/11/84)

The operation with Nelson and the MMU thrust was (thought
to be) necessary to stop the spin of the satellite.  This
spin was not stopped from the ground; rather, the tumbling
and wobbling was stopped.  The satelite was still spinning
when it was grabbed with the RMS.

darrelj@sdcrdcf.UUCP (Darrel VanBuer) (04/11/84)

On Wednesday morning's news, they reported discovery of a fiberglass fiber
on the sattelite's trunion pin, and this was the cause of the inability to
dock.  They also showed some film of the astronauts rehearsing the repairs
(I had been out of the room, but rehersal became obvious when a flock of air
bubbles rolled past the camera lens).  The repair is sufficently large (at
least working inside a space suit) that they are expected to be exhausted at
the end of the day.


-- 
Darrel J. Van Buer, PhD
System Development Corp.
2500 Colorado Ave
Santa Monica, CA 90406
(213)820-4111 x5449
...{allegra,burdvax,cbosgd,hplabs,ihnp4,sdccsu3,trw-unix}!sdcrdcf!darrelj
VANBUER@USC-ECL.ARPA

notes@iuvax.UUCP (04/13/84)

#R:alice:-269200:iuvax:6400001:000:525
iuvax!apratt    Apr 12 12:16:00 1984

One person noted that the NBC coverage of the night launch was the best he'd 
seen.  I would like to call his (and everybody's) attention to the fact that
they were not your run-of-the-mill announcers or correspondents, but the team
of "NBC News Overnight".  That was just one example of those folks doing it
right. Other examples were showing clips from foreign news agencies, including
Tass.  Just wanted to bring Linda and Bill and the show some post-mortem
credit...
						-- Allan Pratt
					...ihnp4!inuxc!iuvax!apratt