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Lunar rescue plan?

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5 minutes ago, KAL 9000 said:

That's so... Kerbal.

Yes, yes it is.

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On 2/20/2017 at 9:27 AM, magnemoe said:

Yes, upper stage not starting was very low chance. 
Simplify stuff was also why they used and separate upper stage. In KSP standard is to have legs on drop tanks and just one engine. 
It would also increase the chance of taking of after an rough landing,
however before out of fuel on first stage they would abort and burn upward then stage and abort to orbit   

Most other failure modes would result in an high speed impact making an rescue irrelevant. 
Most realistic fail scenario I see would be failure to dock the moon lander with the command module. Would it be possible to do an space walk between them? 

My understanding was that LM upper stage failure was the most likely of all imagined Apollo disasters.  Presumably caused by landing too hard.  If at all possible, I'd try to arrange a lift off vehicle [self] tested and ready nearby the landing site (Moon, Mars, wherever).

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6 hours ago, wumpus said:

My understanding was that LM upper stage failure was the most likely of all imagined Apollo disasters.  Presumably caused by landing too hard.  If at all possible, I'd try to arrange a lift off vehicle [self] tested and ready nearby the landing site (Moon, Mars, wherever).

Yes, an hard landing could cause it or do other damage to the accent module. It was probably also why they went for an two stage solution. 
However having an secondary saturn 5 on pad would be unpractical and the life support on the landing module would not last so long, also an high chance the crash landing would damage the life support. 
Outside of this they probably crash tested the landing module to find weak spots, an damage to life support would probably let them cut ground time short and return to orbit. 

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2 hours ago, magnemoe said:

Yes, an hard landing could cause it or do other damage to the accent module. It was probably also why they went for an two stage solution. 
However having an secondary saturn 5 on pad would be unpractical and the life support on the landing module would not last so long, also an high chance the crash landing would damage the life support. 
Outside of this they probably crash tested the landing module to find weak spots, an damage to life support would probably let them cut ground time short and return to orbit. 

As mentioned earlier, having a rocket on standby on Earth is unpractical (especially for Mars), although it was used with last shuttle flights (which would only have to rendezvous in orbit).  A better idea would be to have the lander/ascender already on the Moon.  Such a lander could bring more supplies.  Note that the lower stage could be filled with cargo that wouldn't necessarily require the same shock levels as the ascender, or possibly have them in separate landers (unlikely to be more practical).

The whole idea is that such a "supply rocket" could allow much longer stays while only developing the same sized rocket.  Judging by Neil Armstrong's manual takeover of the landing computer (of the most ideal spot for such a landing), 1960s tech just wasn't up to such a system. 

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16 hours ago, wumpus said:

to have the lander/ascender already on the Moon.

And a quadrocopter to deliver the shipwreckers to stored crackers.

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11 hours ago, kerbiloid said:

And a quadrocopter to deliver the shipwreckers to stored crackers.

You do realize that NASA put a lunar lander in orbit around the moon during Apollo 10?  And that if you wanted to maximize time on the moon, you could fill one with supplies (presumably not including the command module) on Apollo 12 and land (and use them) with Apollo 13 14?  I'm guessing the time constraints were too much (and the computers weren't up to it), but it was hardly on the same realm as your suggestion.

For modern missions, it would make sense to use non-man-rated craft to deliver supplies (especially fuel, probably in entire stages) along the route*.  Having a lunar ascent module isn't changing things all that much.

* "the route" typically is eccentric ellipses with one end in LEO and the other much higher (preferably avoiding the Van Allen belts).  Those belts can be a problem with ion-based (read "slow solar-based" systems).

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1 hour ago, wumpus said:

You do realize that NASA put a lunar lander in orbit around the moon during Apollo 10?  And that if you wanted to maximize time on the moon, you could fill one with supplies (presumably not including the command module) on Apollo 12 and land (and use them) with Apollo 13 14?  I'm guessing the time constraints were too much (and the computers weren't up to it), but it was hardly on the same realm as your suggestion.


Getting supplies from one LM to the other is going to be a problem, as is ensuring the CSM has enough supplies.

Orbital precession has to be considered too - the longer the LM stays on the surface, the greater the divergence between it's launch plane and the CSM's orbit.  IIRC on the later missions, the CSM had to make a plane change burn to stay within the LM's (very limited) capabilities.

Supplies and plane changes aren't the only constraints on the mission however.  When you balance extended stay time vs. the LM's limited lift capacity (for samples) vs. the need to keep the CM's CoG within a very limited range (storing the samples)...  Could you bring back enough to make all the extra expense worth it?

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Before Apollo 12, there wasn't much confidence that they would be able to do precision landings, so it didn't make sense to pre-land equipment or supplies if they ended up more than a kilometer away. Hence, it was never part of the mission profile.

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16 hours ago, Nibb31 said:

Before Apollo 12, there wasn't much confidence that they would be able to do precision landings, so it didn't make sense to pre-land equipment or supplies if they ended up more than a kilometer away. Hence, it was never part of the mission profile.

I'd assume that after Apollo 11 there wasn't much confidence of being able to land in the area previously chosen for a precision landing.  I'd still want to send a lander first for modern missions, if at all possible.  This type of strategy works better if you are willing to use more existing rockets than build a custom "beyond LEO" rocket.  NASA-Congress is stuck with SLS, so that is a no-go.  Spacex might have the option of using some similar with falcon heavy, but seems committed to big rockets as well.  Russia, China, and India might consider using available rockets (Russia especially after what happened to the N-1).

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11 minutes ago, wumpus said:

Russia, China, and India might consider using available rockets (Russia especially after what happened to the N-1).

It'd be very difficult to assemble a lunar expedition with current HLVs. China and Russia have considered multiple launch options with small 35-50 ton class SHLVs (Angara-5V and CZ-5DY) but both have decided to go for full-scale 100+ ton SHLVs.

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If the acent module was leaking fuel and they did not catch it till that did not have enough delta v for orbit, could they use the decent stage for the extra boost?

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1 hour ago, munlander1 said:

If the acent module was leaking fuel and they did not catch it till that did not have enough delta v for orbit, could they use the decent stage for the extra boost?

The decent stage was always planned to remain on the moon.  Did they "just" use the descent stage during Apollo 13 (for all available burns) or did they use it up and move on to the ascent stage?  I'm pretty sure the ascent stage didn't have the fine control the descent stage had.

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1 hour ago, munlander1 said:

If the acent module was leaking fuel and they did not catch it till that did not have enough delta v for orbit, could they use the decent stage for the extra boost?

The descent stage was pretty much dry after landing, i.e. the extra boost would have been mostly irrelevant. Also, as was the case with the extended nozzle on Apollo 15, there was quite some risk that the nozzle would be damaged on landing, making it impossible to use the engine again.

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