db@harpo.UUCP (04/09/84)
#N::37800001:000:737 !db Apr 9 09:33:00 1984 Did anyone notice that two networks had conflicting reasons why the dock with Solar Max was in trouble? One set of astronaut-consultants was explaining that the trouble was with the satellite attitude control system not being turned off by Goddard, and the other set was saying the problem was with the docking mechanism. By the way, does anyone know why the astronauts cant just go out to the satellite and replace the defective modules without bringing it to a stop? I suppose it could be tricky if they had to fight centrifigal force, but seems they could somehow anchor themselves. Wouldnt seem to be any worse than working on something in earth gravity, except that anything you drop would fall out on a tangent instead of down.
ee163aca@sdccs7.UUCP (04/10/84)
[] Can anyone tell me why NASA didn't have enough fuel for its MMUs. It seems logical to have some spare nitrogen to refuel the things with, rather than jeapordize the whole mission because they ran out of gas. I can understand running low on fuel for the manuvering (sp?) the shuttle, but for the backpacks? If all they can do is move up a few hundred yards and come back, what good are the MMUs. Oh well, at least they got the thing down with the robot arm. Paul van de Graaf sdcsvax!sdccs7!ee163aca
brahms@trwspp.UUCP (04/10/84)
[}{]
> By the way, does anyone know why the astronauts cant just go out to the
> satellite and replace the defective modules without bringing it to a
> stop?
Remember the law: For ever action, there is an equal and opposite reaction.
Therefore, any force applied to the satilite would cause the satlite to
start moving (rotating) in the opposite direction. Not what you really
want to happen. It is a lot easier to work on an object the is secured.
-- Brad Brahms
usenet: {decvax,ucbvax}!trwrb!trwspp!brahms
arpa: Brahms@USC-ECLCalb@alice.UUCP (Adam L. Buchsbaum) (04/11/84)
There was plenty of fuel for the MMU's. It was (is) the shuttle that was (is) running out of propellent.
osd7@homxa.UUCP (Orlando Sotomayor-Diaz) (04/11/84)
So the MMU's fuel reserve was OK, but not the shuttle's. What good is the shuttle then? -- Orlando Sotomayor-Diaz/AT&T Bell Laboratories/201-949-1532 ....ihnp4!homxa!osd7 /Crawfords Crnr. Rd., Holmdel, NJ, 07733
wmartin@brl-vgr.ARPA (Will Martin ) (04/11/84)
I'm mystified about this business regarding the fuel for the MMU's vs the Shuttle maneuvering fuel. Not only the network news people (NBC) but also the advisors (astronauts, scientists, whoever) were specifically discussing that Pinky's MMU fuel gauge was "red-lined"; that he only had enough MMU fuel to get back to the Shuttle, so he had to let Solar Max go and get back. There was no choice; it was a "mission rule". I assumed he ran out because he had the MMU thrusters on full while he hung on to Max trying to slow its rotation. It wasn't surprising that he would run out. And since they wanted to do the activity in sunlight, they had to wait until the next orbit anyway to continue, as they approached nightside. But what irked me was that NOBODY (advisors, newscritters, whatever) ever mentioned refueling the MMU -- they talked about using the OTHER MMU. They never said that it wasn't possible, that it would be possible but wasn't wise or safe, or that there wasn't any source for more MMU fuel, or ANYTHING! They just left the topic hang! Now I see net discussion saying that it wasn't the MMU fuel, but the shuttle thruster fuel that was the limiting factor. That is NOT what was clearly and specifically said at the time. The term "red-lined" was used repeatedly, and it was the MMU they were referring to. Now that the point is moot, I expect no one will ever say anything publically about it again, but I still am irritated by the failure of the people on the tv to ask and answer the OBVIOUS questions that occur to the audience. Will
karn@allegra.UUCP (Phil Karn) (04/12/84)
As I understood it from the later news reports, Nelson's MMU did indeed require refilling, but it was far from empty - just at the point where the rules required a return. However, the crew tried a grab with the RMS arm later even with the nutation that had been introduced earlier and it was this attempt that ran the forward RCS propellant below the level at which further use of the MMU could be allowed. It was flatly stated then that the MMU would not be used again on this flight. However, this morning after the repair operation had been completed, they did indeed try out the MMUs again untethered! I guess the rules can be bent a little. It had occurred to me too at the time Nelson attempted to grab the solar array that this was an ill-advised thing to try. The possibility of introducing nutation didn't occur to me right away, I was more concerned about damage to the array arm. I also noticed later on, before we heard stories about the ground's concern, that the solar panels no longer seemed to be tracking the sun. I suspect that there will be some pointed questions asked of the crew after this mission, at least in private. Phil
barmar@mit-eddie.UUCP (Barry Margolin) (04/15/84)
-------------------- From: wmartin@brl-vgr.ARPA (Will Martin ) But what irked me was that NOBODY (advisors, newscritters, whatever) ever mentioned refueling the MMU -- they talked about using the OTHER MMU. -------------------- I think I was watching CNN when this was going on, and I distinctly remember them mentioning refueling the MMU that was being used. -- Barry Margolin ARPA: barmar@MIT-Multics UUCP: ..!genrad!mit-eddie!barmar