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Post by Count Zero on Aug 25, 2008 7:53:12 GMT -4
Interesting! Thanks Bob.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Aug 25, 2008 8:51:14 GMT -4
The earlier missions used a different lunar rendezvous technique. I don't recall the details, but I could look them up if needed. The technique used during Apollo 11 & 12 took more time (about 3.5 hours from orbit insertion to docking) but was considered safer. With the experience of a couple missions under their belt, NASA switched to a shorter rendezvous (less than 2 hours) from Apollo 14 onward. The shorter rendezvous used the additional APS burn.
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Post by PeterB on Aug 27, 2008 10:13:20 GMT -4
What was the endurance capability of the ascent stage? I didn't see that info in the links. I can't give you exact figures, but I remember reading that on Apollo 13, they managed to stretch consumables intended for 2 people for 2 days to provide for 3 people for 4 days. Given that Apollo 13 would have been on the surface of the Moon for well over a day, and that there was a landing sequence before that, it sounds like the LM crew lifted off with somewhere between 6 and 12 hours of consumables. Presumably if the need had arisen, they could have stretched those consumables out to some extent.
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Post by PhantomWolf on Aug 27, 2008 15:10:47 GMT -4
The Ascent Stage only had about 10 hours I believe, I'm sure I found it somewhere when researching my for my website, the main tanks with the Oxygen, Water and the batteries were all in the Descent Stage with only minimal supplies in the Ascent Stage. During Apollo 13 they did bring the LM to life using the Ascent Stage batteries after losing power to the CM.
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Post by echnaton on Aug 28, 2008 10:48:22 GMT -4
One of the last actions before ignition of the ascent engine was the firing of a charge that propelled a guillotine to sever the electric and consumable connections between the stages. Once that charge was fired, if the ascent engine didn't fire the lower stage consumables were irrelevant. They only had the time provided by the limits of the upper stage to get to orbit and rendezvous.
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vq
Earth
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Post by vq on Aug 28, 2008 23:45:08 GMT -4
I can't give you exact figures, but I remember reading that on Apollo 13, they managed to stretch consumables intended for 2 people for 2 days to provide for 3 people for 4 days. Actually, didn't they have the descent stage attached the whole flight for Apollo 13? I've read in the links provided (IIRC) that the descent stage had 4500 Ah of juice while the ascent stage had more like 1500. I suppose this was the limiting factor in orbit, since the same environmental control systems were used and oxygen doesn't seems to usually have a little extra supply. So the 10 hour number sounds pretty close, which gives a pretty good safety margin for a trip designed to take 3 1/2 hours. Edit: Fixed the quote.
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Post by Ginnie on Aug 30, 2008 21:52:16 GMT -4
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vq
Earth
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Post by vq on Sept 3, 2008 1:20:10 GMT -4
Great pics. I've seen LM's at the NASM and Kennedy, but there's something unique about seeing them pre-launch. I especially liked the descent stage view - I'd never seen a shot of them before being mated.
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