Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Feb 24, 2006 18:43:28 GMT -4
Space is obviously a problem because the CM was built for only three people and had only three couches. I doubt modifications could be easily or quickly made to accommodate more people.
All three crew members had a pressure suit and the CM could be depressurized and egress was possible through the side hatch. This was actually done on Apollo 15-17 to retrieve film from cameras in the SM. I believe all three astronauts were connected to the CSM life support systems during these EVAs. The only portable systems were the ones used on the moon (the PLSS backpacks) and these were discarded before the astronauts returned to orbit.
I believe transferring from one vehicle to another via EVA was a contingency plan in case the LM couldn't re-dock with the CM after returning to lunar orbit. So surely NASA must have worked out a way to do this, though I'm not sure exactly what it was. Maybe it's possible to quickly disconnect from one life support system and connect to another while in a vacuum.
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Post by dwight on Feb 25, 2006 7:25:59 GMT -4
One other hypothetical scenario, and may I say this thread is really informative:
Say the LM and CSM had just seperated for Lunar descent. That moment when the LM is rotated for inspection by the CMP, would it have been feasible to redock following the explosion? I would imagine yes but with extreme difficulty, given that the CSM would probably be rotating and girating because of the explosion.
Could you imagine watching that scenario live on TV? The more I read about the whole drama, the more I think the explosion happened at the most opportune moment.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Feb 25, 2006 10:29:01 GMT -4
Maybe it's possible to quickly disconnect from one life support system and connect to another while in a vacuum. Well, there were a few litres of air contained in the suit itself...
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Post by mid on Mar 2, 2006 21:59:41 GMT -4
One other hypothetical scenario, and may I say this thread is really informative: Say the LM and CSM had just seperated for Lunar descent. That moment when the LM is rotated for inspection by the CMP, would it have been feasible to redock following the explosion? I would imagine yes but with extreme difficulty, given that the CSM would probably be rotating and girating because of the explosion. Could you imagine watching that scenario live on TV? The more I read about the whole drama, the more I think the explosion happened at the most opportune moment. The fact is, at just about any other place along the flight path of Apollo 13, the explosion would've been fatal to the crew. You are correct in your idea that the occurrance happened at the most opportune moment. The scenario you mention would have possibly been a fatal one. First of all, the oscillations to the CSM attitude due to the explosion would've been greater than they were in cis-lunar space with the LM attached, and may have posed a serious problem for the CMP to stabilize. If he could've stabilized it, he would've been the one responsible for executing the docking, after both craft probably expended alot of fuel trying to get properly aligned again. If the CMP couldn't stabilize the vehicle to insure a docking, the whole thing would've been lost at that point One of the problems with Apollo 13 was that power rapidly died in the CM. They had to get the vehicle powered down completely to conserve the CM batteries for the re-entry into earth's atmosphere...infact, they had to use LM power to re-charge one of the CM batteries. Executing a docking may have drained those batteries beyond their ability to support re-entry. Additionally, there is a big difference between using the LM DPS to boost a free-return trajectory and using it to execute TLI. That may have posed a problem, although I think it could've been done, despite the lack of CSM platform that would've been necessitated by a power-down. But I think the CSM would've been in a very bad situation in lunar orbit without the LM attached, and would've consumed far too much power to allow for a successful return to earth.
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Post by mid on Mar 2, 2006 22:17:41 GMT -4
Space is obviously a problem because the CM was built for only three people and had only three couches. I doubt modifications could be easily or quickly made to accommodate more people. All three crew members had a pressure suit and the CM could be depressurized and egress was possible through the side hatch. This was actually done on Apollo 15-17 to retrieve film from cameras in the SM. I believe all three astronauts were connected to the CSM life support systems during these EVAs. The only portable systems were the ones used on the moon (the PLSS backpacks) and these were discarded before the astronauts returned to orbit. I believe transferring from one vehicle to another via EVA was a contingency plan in case the LM couldn't re-dock with the CM after returning to lunar orbit. So surely NASA must have worked out a way to do this, though I'm not sure exactly what it was. Maybe it's possible to quickly disconnect from one life support system and connect to another while in a vacuum. The method planned for the latter contingency was to utilize the OPS (Oxygen Purge System), which was the smaller top part of the backpack assembly that you saw the crews wearing on the lunar surface (consisting of a PLSS and an OPS on top of the PLSS). These OPSs were retained by the crews in the LM after EVA for possible use in the emergency EVA scenario you described. Their purpose was two fold...to serve as emergency oxygen in case of a failure of the PLSS on the lunar surface, or for the emergency EVA to get back into the CM in lunar orbit because of a failed docking of some sort. The OPS contained enough oxygen to maintain nominal suit pressure for about an hour at it's normal "low-flow" rate...about 30 minutes at its high flow setting.
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