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Post by ka9q on Feb 10, 2011 8:55:04 GMT -4
Just when you think you've discovered all the really interesting stuff in Apollo, you come across something you never heard of before.
I just discovered Lunar Escape Systems. The idea was to provide an alternative to being stranded on the moon if the LM ascent stage failed. It was considered for long duration stays since the probability of some failure making the LM unusable would increase with time.
The idea was, quite literally, for the astronauts to wear their regular surface EMUs (suits and life support backpacks), strap on one (or several small) rocket engines, and blast themselves manually into orbit using propellants siphoned from the LM's ascent stage tanks. (This presumes that loss of those propellants wasn't the reason for the LM becoming unusable in the first place!)
The idea was pretty speculative but it did result in some pretty thick design study documents. All of the diagrams resemble various kinds of rocket powered lawn chairs that look very like something out of a Mythbusters episode. Guidance would have been nearly manual as ordinary computer control was well outside the weight budget. The big problem was ensuring that the astronauts could make it into orbit and rendezvous with the CSM before their PLSS consumables ran out.
Imagine what riding that thing into lunar orbit would have been like. The view would have been a lot more impressive than through those small LM windows!
Anybody else ever come across this? The Wikipedia article is a pretty good start.
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Post by echnaton on Feb 10, 2011 11:55:43 GMT -4
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Post by echnaton on Feb 10, 2011 12:13:06 GMT -4
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Post by banjomd on Feb 10, 2011 12:25:21 GMT -4
I've read about the concept...FASCINATING! and yes, probably one heck of a ride! The reason it was never built was that NASA found out that, if they just faked the landings, there was no need for an escape system!
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Post by LunarOrbit on Feb 10, 2011 13:29:38 GMT -4
Wow... that is crazy... and there would be no way to test it first either. But I guess if your only other option is to be stuck on the Moon it would be worth trying.
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Post by echnaton on Feb 10, 2011 14:39:00 GMT -4
With a timer and a good inclinometer, it would seem that a skilled pilot could have a chance of hitting a reasonable orbital altitude. The real problem it seems to me would be plane change. Either one needed to meet the CSM or avoiding a change that was out of the ability of the CSM fuel budget or put the passengers over the time limit for oxygen. It seems like that problem could have only be solved with a guidance system of some sort. I guess the simplicity of design would have made an engine restart problematic.
So which would be worse. Die in the LM when the oxygen runs out, die in orbit when the PLS oxygen runs out or die because your miscalculations in flight put you in an orbit that intersects the surface? Rather grisly to contemplate.
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Post by banjomd on Feb 10, 2011 16:32:28 GMT -4
This'd be a nice simulator!
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Post by ka9q on Feb 10, 2011 19:27:48 GMT -4
Seems to me it shouldn't be that difficult to get into the correct orbital plane. Just use lunar landmarks for left-right steering.
I'd think it would be harder to get the eccentricity right. On Apollo 10, after they went into the descent orbit with 50,000' perigee (where an actual landing would begin powered descent) the LM crew said they had to fight the urge to close their eyes and lift their legs to avoid dragging them on the mountain peaks not far below. And that view was through those tiny LM windows. Orbiting the moon at low altitude in just a spacesuit would be an especially unforgettable part of an unforgettable experience.
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Ian Pearse
Mars
Apollo (and space) enthusiast
Posts: 308
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Post by Ian Pearse on Feb 11, 2011 9:52:41 GMT -4
Arthur C Clarke wrote a great short story on this idea - a man in orbit around the Moon in just a suit... cannot for the life of me remember the name of the story, but worth getting hold of.
Edit: It was "Maelstrom II", I have it in the "The Wind From The Sun" collection. Excellent stories all round.
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Post by Count Zero on Feb 11, 2011 11:28:17 GMT -4
I remember that one! Can't recall the name, but the ending was awesome. Orbital dynamics for the win!
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Post by Kiwi on Feb 11, 2011 11:45:32 GMT -4
...the [Apollo 10] LM crew said they had to fight the urge to close their eyes and lift their legs to avoid dragging them on the mountain peaks not far below. Sure that wasn't Jim Irwin? Just when you think you've discovered all the really interesting stuff in Apollo, you come across something you never heard of before. That's the beauty of Apollo, and it makes me feel sorry for the likes of Hagabardceline who are incapable of removing their blinkers and seeing Apollo for the truly magnificent feat that it was. I doubt that any interested person could ever stop learning. There's so much fascinating stuff we can delve into, such as John Houbolt's incredible battle to get lunar-orbit rendezvous recognised, or Ed Fendell's career with Nasa. I spent a fascinating time learning to identify MOCR staff in Nasa's Apollo documentary movies. At 0:08:19 in Al Reinert's movie "For All Mankind" one guy is incorrectly labelled Steve Bales, and I was keen to identify another guy in "Apollo 13: Houston, We've Got a Problem" who sometimes has the real Steve Bales sitting next to him and is doing something that's rare these days: Working out involved sums on a piece of paper with a pencil. That was Will Fenner. Young people sometimes scoff at Nasa when they see film clips of exploding rockets, but they don't realise that when you're learning to do something that no-one else has ever done, trial-and-error is sometimes the only way to go, and you're bound to make a few mistakes. I feel really privileged to have seen Sputnik 1 (or the rocket that put it up) passing overhead less than a week after it was launched, and to have listened to the first moon-landing live on the radio. Those were exciting times.
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Post by chew on Feb 11, 2011 19:56:27 GMT -4
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Post by Obviousman on Feb 12, 2011 3:25:12 GMT -4
I think the Apollo 10 reference is correct. IIRC, Cernan remarked in his autobiography that although they were at some altitude (14,000m ?) it make him a little nervous because he knew that there were very high ranges on the lunar surface (even though the clearance was about 8km!).
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Post by ka9q on Feb 12, 2011 5:54:32 GMT -4
The history of manned space flight by David Baker(?) Hmm, I have that volume and read much of it back in the 1980s. But I don't remember reading about the LESS, I must have missed it.
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Post by ka9q on Feb 12, 2011 5:56:04 GMT -4
I think the Apollo 10 reference is correct. Maybe it was all of them. Certainly Scott and Irwin had a spectacular ride over the mountains on the way to their landing site.
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