If the astronauts on Apollo 11 had landed safely on the moon but could not take off, would there have been a rescue mission?



Say they landed on the moon but discovered the ship was damaged during the landing and they could not launch again.

What would have been the plan? Would another crew have been sent to rescue them? Would the astronauts just have to wait till they ran out of supplies to die or was there a procedure in place for them to commit suicide in a painless way? How long could they have survived on the moon?


Posted 2017-05-24T11:32:32.803

Reputation: 586


Apollo XI did not have enough potatoes (or other things) to last until Apollo XII would be ready ;)

uhoh 2017-05-24T13:40:54.343

I seem to remember reading that the Soviet plan was for their cosmonauts to be national heroes and not come home (because of a lack of a plan for a return) - can't find any confirmation on the internet thoughStephen S 2017-05-24T13:57:24.097

@StephenS Sounds like a myth; they definitely had plans for a return. Risky, inelegant plans, but they definitely existed.DylanSp 2017-05-24T13:59:43.607

3@Uwe Apollo 13 proved that the LM could support three astronauts for long enough to return from the Moon with very little support from the CSM. Not that it was in any way a comfortable trip, but I think in some sense people put up with worse in airliners these days, so...Michael Kjörling 2017-05-24T15:53:38.053

3Frankly, I'm having a hard time imagining anything that could happen during descent which would render the LM incapable of flight after landing, yet still allow the crew to land safely. A more likely scenario if anything too far out of the ordinary happened during descent would likely be for the crew to initiate a landing abort, dump the descent stage and return to the CSM. (Lives are more important than equipment or money.) Remember that the LM descent and ascent stages were effectively two separate spacecraft with a shared cockpit and some shared electronics (guidance, life support, etc.).Michael Kjörling 2017-05-24T16:09:17.770

@MichaelKjörling The only scenario I thought of would be landing in extremely rough terrain in such a way that the LM tipped slowly over onto rocks that breached one of the ascent propellant tanks. If they didn't stage-abort immediately, they could lose the ascent option while the cabin was still intact. Extreeeeeeeemely improbable, I grant.Russell Borogove 2017-05-24T16:33:31.277

8@MichealKorörling The astronauts could easily have been stranded on the moon, however it would probable not be because of descent damage.. Because of the ascent stage's corrosive fuel, the engine could not be test fired beforehand, so the ascent was the first time the engine was fired. A defect in the engine could easily strand the astronauts on the moon.Hyperdrive enthusiast 2017-05-24T16:42:05.317


@Hyperdriveenthusiast However, a failure of the ascent engine itself is probably less likely than many other astronaut-stranding failure modes: https://space.stackexchange.com/questions/19853/how-reliable-are-pressure-fed-hypergolic-engines

Russell Borogove 2017-05-24T16:44:37.280

@RussellBorogove Thanks for the infoHyperdrive enthusiast 2017-05-24T17:10:07.683


@MichaelKjörling, actually it very nearly happened. When Armstrong and Aldrin climbed out of the LM, one of them bumped and broke the breaker switch that armed the ascent engine. Aldrin jury rigged a repair with his pen. Had they not been able to do that, they would have been stranded. http://www.cnbc.com/id/42592372

Seth R 2017-05-24T17:29:09.530

@SethR Interesting. Makes me wonder what would happen if, had they not been able to fix that, they just pushed the ABORT button after conclusion of the EVA. But that's a separate question.Michael Kjörling 2017-05-24T17:30:59.000

5I would imagine that given plenty of time, they could have taken apart the switch and "hot-wired" the ascent arm.Russell Borogove 2017-05-24T17:52:20.137

2Yeah.. slow death, or open the panel and short out the breaker. Not a difficult decision.Martin James 2017-05-24T19:43:30.850

3There was no rescue mission possible, Apollo 12 was not ready at launch site and could not land exactly at the landing site of Apollo 11 without any astronauts as pilots. The lunar module had no space for three or even four astronauts in their suits. Every astronaut had to wear a suit to open the hatch of the LM.Uwe 2017-05-24T19:44:48.710

@MichaelKjörling Apollo 11 also had a slug of helium freeze in the fuel lines immediately after landing, with some alarming pressure effects. It melted (sublimed?) shortly before there would have been a problem, but that briefly threatened to vent all their fuel right after they landed.fectin 2017-05-25T03:49:25.433

13Even if another rocket had been ready to go immediately, you need to factor in the amount of time that would be required to analyze why the landing failed and to develop new procedures or make modification to the next craft. There's no point in sending a second craft along if its just going to suffer exactly the same fate.Damien_The_Unbeliever 2017-05-25T06:56:33.607

@Michael Kjörling: But Apollo 13 did prove that the LM life support system was not able to remove all of the carbon dioxide exhaled by three astronauts. But some hours should be possible due to the slow rise of the carbon dioxide level over time.Uwe 2017-05-25T09:44:52.337


@fectin - it wasn't the helium that froze, but fuel: ...fuel in the fuel/helium heat exchanger was frozen by the helium flowing through the heat exchanger...

Johnny 2017-05-27T02:10:51.060

@Uwe the carbon dioxide problem in the LM was mainly due to 3 being present instead of the designed for 2. Overloading the system - in this case with good reason.Solar Mike 2017-05-28T06:10:23.457

@Damien_The_Unbeliever to expand on your point a bit... even if the failure mode which befell the initial mission was addressed in the rescue vehicle, there is still the potential for any of countless other ways in which a rescue mission could go awry, adding the rescue crew to the souls lost in the initial mission. Given that the rescue vehicle is just another copy of the original with at best a few tweaks, a rescue crew would be undertaking as much or more risk as the initial, making even the contingency planning for such a thing pointless.Anthony X 2017-05-28T22:36:30.017

I've read somewhere that Apollo 11 was very low on fuel by the time it landed; only 24 seconds reserve or something like that. They were close to aborting the landingBen Hillier 2017-05-29T15:24:46.340


@BenHillier Yes, Apollo 11 landed with very low amounts of descent fuel remaining, because of the extended landing process. https://en.wikipedia.org/wiki/Apollo_11#Landing This has been dramaticized and illustrated in a number of places, or you can just turn to NASA's CAPCOM transcripts which highlight this directly by the fuel calls and event timestamps.

Michael Kjörling 2017-06-30T09:06:42.643



The following is a speech written for President Nixon, in the event that the Apollo 11 mission did not succeed.

Fate has ordained that the men who went to the moon to explore in peace will stay on the moon to rest in peace.

These brave men, Neil Armstrong and Edwin Aldrin, know that there is no hope for their recovery. But they also know that there is hope for mankind in their sacrifice.

These two men are laying down their lives in mankind's most noble goal: the search for truth and understanding.

They will be mourned by their families and friends; they will be mourned by their nation; they will be mourned by the people of the world; they will be mourned by a Mother Earth that dared send two of her sons into the unknown.

In their exploration, they stirred the people of the world to feel as one; in their sacrifice, they bind more tightly the brotherhood of man.

In ancient days, men looked at stars and saw their heroes in the constellations.

In modern times, we do much the same, but our heroes are epic men of flesh and blood.

Others will follow, and surely find their way home. Man's search will not be denied. But these men were the first, and they will remain the foremost in our hearts.

For every human being who looks up at the moon in the nights to come will know that there is some corner of another world that is forever mankind.

This confirms there were no plans for a rescue mission if Apollo 11 wasn't successful.


Posted 2017-05-24T11:32:32.803

Reputation: 2 527

3+1 for supporting information.uhoh 2017-05-24T12:52:44.533


relevant xkcd: https://xkcd.com/1484/

Kartik 2017-05-24T13:47:33.563

5I'd read some political fiction, in a world when Nixon had to deliver this speech.Agent_L 2017-05-25T09:35:57.203


relveant Vsauce: https://youtu.be/QBK3QpQVnaw?t=564

Melkor 2017-05-25T15:30:54.667

1If only NASA took this much risk now, we might get beyond "plans" to go anywhere.Jonathan. 2017-05-29T18:27:18.427

1This might suggest there were no plans for a rescue, but it hardly confirms it.Matthew Burke 2017-05-30T12:44:09.003

No, but it pretty much confirms it really happened, and wasn't some 'conspiracy'. Why fake a landing to claim you got there first, and write a speech saying the astronauts were lost? Could be awkward next time they're seen in public..Flynn1179 2017-05-30T12:54:38.320

1Not to go full-on conspiracy theorist, but if you're already faking a full on moon landing, you might as well let some cluless WH writer throw together some speech for Nixon... ;)SAnderka 2017-05-31T15:22:05.790


The Apollo lunar module was battery powered, so could only maintain a livable environment for a few days (this was a major concern for Apollo 13, since the crew was reliant on the LM after the accident which disabled the service module). Once out of power, it would be unable to circulate air or to maintain a comfortable temperature inside.

Committing suicide on the moon, fortunately, is trivially easy. Once the LM was nearly out of power, they could depressurize the LM cabin while their suits weren't sealed (or exit the LM and then unseal their suits). They'd lose consciousness in a few seconds, albeit with some discomfort from the rapid depressurization, and die shortly thereafter.

As noted in other answers, there was not another rocket stacked and ready to launch in time to effect a rescue. If there had been, time would be very tight; the maximum surface stay of any of the Apollo landers (Apollo 17) was shorter than the Earth-moon flight time; I don't know if the LM endurance was longer than that, but it's conceivable that the astronauts could survive long enough to await rescue.

The crew transfer might be a challenge: the rescue crew would have to be suited up (because the entire cabin depressurizes to open the hatch; there's no airlock) and the rescuees would have to be suited up and wearing the bulky portable life support pack. They'd have to transfer one at a time, discarding their PLSS after connecting to the cabin environmental system. I'm not certain it would be physically possible to get four suited crew inside. I believe the extra mass would not be a major problem; the LM ascent stage was intended to return with about a human's mass worth of moon rocks, and usually completed its ascent with 150kg or more propellant remaining in the tanks. If it was limited to a lower orbit than usual, the command module could come down to reach it.

The alternative would be to land the rescue ship with a single crew member; this would be hazardous, but likely possible. The LM guidance computer was capable of semi-autonomous landing, and they'd have time on the outbound trip to program the precise location of the disabled lander as a target site. Three people could definitely fit in the LM (as demonstrated by Apollo 13).

Russell Borogove

Posted 2017-05-24T11:32:32.803

Reputation: 57 784

9I don't believe the cabin environmental system did have connections for up to three or even four suited astronauts. Apollo 13 only demonstrated that three people without suits would fit in the LM.Uwe 2017-05-24T15:05:54.730

8Air is not as good an insulator as vacuum.ShadSterling 2017-05-24T15:17:47.240

@Uwe Good point. Maybe pairs of crew could alternate connection to the cabin environmental system for a minute at a time during the transfer -- the suit air wouldn't go bad immediately when disconnected. Once transfer was complete, they could repress and would only have to manage for a short period of time after that.Russell Borogove 2017-05-24T15:21:06.407


We have already discussed and concluded that a single crew member could fly the LM. Admittedly, that question is about ascent, whereas this would be about descent. Absent problems during the descent, though, I suspect the two situations would be similar.

Michael Kjörling 2017-05-24T15:57:56.193

@Polyergic The LM was built to maintain a comfortable temperature with the electronics on. If you are dumping heat into radiators and there's nothing to heat the interior, then the interior will cool off (as 13 demonstrated), and there was apparently no way to seal the circulation into the radiators (otherwise I don't see why it wasn't done). Though I wonder if keeping some, but not all, electrical loads turned off (to reduce the battery load), and starting a PTC roll, would have been sufficient to maintain heat distribution and maybe even provide a better environment for the crew members.Michael Kjörling 2017-05-24T16:00:24.793

@Russell Borogove: A disconnected suit would contain a lot of oxygen, but without forced circulation of oxygen, only the oxygen in the helmet could be used for breathing. There should not only be enough oxygen to breathe, the level of the exhaled carbon dioxide should be lower than about 8 %. But the exhaled oxygen contains about 4 % of carbon dioxide.Uwe 2017-05-24T20:03:31.177

Re crew transfer: Regardless of whether it's possible to get four crew inside a CM, unless there are four seats rigged up I don't think EDL will be safely accomplished for the fourth. I'm not sure if there were ever any provisions for rescue seats in the CM?Erin Anne 2017-05-24T20:41:29.747

2@ErinAnne In this scenario, the first crew still has a good CSM in lunar orbit; two rendezvous would be doable in order to get all the crew into their own ships. I think there was a proposal for a rescue version of the CM with room for another one or two crewmen in the lower equipment bay, but never developed. If my choices are certain death on the moon or laying across my buddies' laps for a 6G reentry, I'll take the chance...Russell Borogove 2017-05-24T22:05:24.560

@Uwe Yeah, it would be risky at best. LMP-2 disconnects, LMP-1 plugs in, the two LMPs try to get LMP-1's PLSS off, CDR-2 watches LMP-2's face and swaps umbilicals when he sees LMP-2 start to fade, all of this in a very cramped space. Maybe not doable.Russell Borogove 2017-05-24T22:08:47.027


@ErinAnne Here's the "rescue CSM" info: http://www.astronautix.com/a/apollorescuecsm.html

Russell Borogove 2017-05-24T22:10:56.780

12From tragic Kerbel Space Program Experience. Never set the precise location of the stranded lander as your destination. That's how you get two stranded landers and have to mount another rescue mission. Set a point a few meters away!Scott 2017-05-24T22:50:06.790

Another caveat: With a 100% failure rate on take off from the Moon so far it would have been considered very risky to land another person on the Moon.kasperd 2017-05-29T21:19:29.900

That would depend entirely on the failure mode that stranded the first lander.Russell Borogove 2017-05-29T22:57:25.293

"but there would be no air on the other sides to insulate it from radiating all its heat away" - Vacuum insulated much, much better than air.aroth 2017-05-30T06:03:06.020

@Russell Borogove: swaping umbilicals could be avoided by using splitters to connect two suits to one plug. But these splitters should be designed and build in a hurry just before the start of the rescue mission. The life support system should deliver an oxygen flow rate sufficient for four instead of two astronauts.Uwe 2017-06-02T09:44:39.603


There was no chance to get them back alive - no ready to launch rocket, no ready to launch spaceship, no lunar module capable to take 3 persons (or land automatically) - just nothing.

Pavel Bernshtam

Posted 2017-05-24T11:32:32.803

Reputation: 1 006

1The LM could take three people for the short ascent flight, possibly even 4.Russell Borogove 2017-05-24T14:47:44.003

@RussellBorogove - was it possible to leave command module without a commander and then dock to it?Pavel Bernshtam 2017-05-24T15:12:42.007

3I'm not sure. The ascent module was normally the "active" partner in the rendezvous (with the CM ready to take over as active if necessary. I don't know if the command module pilot was required to do something physical with the docking/access hatch to reset it after departure. Why? I'm assuming the first mission's CSM is still around, and we can do two rendezvous to get all the crews back to their respective CSMs instead of piling 4-5 people into one.Russell Borogove 2017-05-24T15:25:43.167

Collins, after the Apollo 11 LM departure: "now I have to do the tunnel bit again, closing hatches, installing drogue and probe, and disconnecting the electrical umbilical running into the LM."Russell Borogove 2017-06-02T18:44:11.937


As others have said, no. There was nothing in place to allow a rescue mission in time to save a stranded crew. This was why the LEM had a separate ascent engine, tucked up in the ascent stage. No matter what happened during landing, it would be basically impossible to disable the ascent engine without killing the crew anyways.


Posted 2017-05-24T11:32:32.803

Reputation: 604

2Actually I think a major driver, if not the reason, for having a separate ascent stage was to save weight. Remember that the LM's mass budget was extremely tight. If you can spend a little extra mass during descent in order to have a considerably lighter craft during ascent (which is when you want said craft to carry, say, lunar material samples), that might very well make sense. The fact that you get an extra engine is a bonus in some situations, but I'm fairly sure that getting a stranded crew off the ground was not a primary driving reason for that choice. If so, make it reliable instead.Michael Kjörling 2017-05-28T12:02:10.100

1The landing feet, empty tanks, stronger engine and prospecting gear were all dead weight for the ascent. The condition of the decent motor could have been compromised as well. The disposable lander base was far superior if no reuse was anticipated.KalleMP 2017-05-28T14:11:17.520

2@MichaelKjörling You're right. I knew that the reason most of the mass was left behind was to save mass, but I didn't realize that a much smaller engine would be capable of takeoff because of that. I have read that having a backup was a significant factor, but what you're saying definitely makes sense.Deimophobia 2017-05-28T17:39:52.837


Dig this:

The Rescue Agreement was considered and negotiated by the Legal Subcommittee from 1962 to 1967. Consensus agreement was reached in the General Assembly in 1967 ( resolution 2345 (XXII)), and the Agreement entered into force in December 1968. The Agreement, elaborating on elements of articles 5 and 8 of the Outer Space Treaty, provides that States shall take all possible steps to rescue and assist astronauts in distress and promptly return them to the launching State, and that States shall, upon request, provide assistance to launching States in recovering space objects that return to Earth outside the territory of the Launching State.


Effector Dhanushanth

Posted 2017-05-24T11:32:32.803

Reputation: 109

6Interesting, but the USA was the only state that could potentially launch a rescue mission at the time. Availability of a launcher was more of a factor than legal agreements.Hobbes 2017-05-27T08:56:04.037

4OK but how does this answer the question?David Richerby 2017-05-28T17:20:00.313


I've heard about something, but im not sure of its validity because I wasnt paying attention to where I heard it. Someplace Ive read about some sort of handheld mini ascent stage. Pretty much, two stranded astronauts outside the lander grab on this thing and activate an engine to go to orbit. Pretty much a rocket stick with two handles. This may have been only in planning, im not sure, but astronauts would then need to survive on suit o2 until the CSM picks them up. Any confirmation or denial is welcome.


Posted 2017-05-24T11:32:32.803

Reputation: 36


You're correct, there were plans for a Lunar Escape System: https://en.wikipedia.org/wiki/Lunar_Escape_Systems

Hobbes 2017-05-28T08:23:01.723

1But these were for long-duration missions that were being considered as a possible extension of the Apollo programme. They weren't being considered for Apollo 11 or any of the missions that were flown, or even planned and then cancelled.David Richerby 2017-05-28T17:25:00.497


At the time of Apollo 11, there weren't any systems in place for a surface rescue, but several possibilities were explored during the development of the Apollo program.

One of the more promising was the Gemini Lunar Rescue Spacecraft, which would be based on the older 2-man Gemini capsule.

Lunar rescue mockup Lunar rescue mockup

This would either land uncrewed near the planned landing location for the crew to escape in, or just wait for a rescue mission to be assembled. Alternatively it would act as the rescue craft, with additional seats for the stranded Apollo astronauts as well as its own crew.

Oddly, this was vehicle was planned to use two Apollo service modules as upper stages to boost it to the moon. I'm not sure why the SM was chosen though, since a large portion of its internal volume was devoted to life support equipment

Apollo SM as upper stages


Posted 2017-05-24T11:32:32.803

Reputation: 153

SM was probably chosen because they had extant spares.Joshua 2017-09-03T04:09:54.597


Basically, NO. That is why the LEM Ascent module engine was designed to be extremely simple: Propellants were pressurized by a single helium tank and a single valve. ( fewer points of failure ). Fuel and oxidizer were self-igniting. Once that valve opened, they were going up.

At least that is what I read years ago.


Posted 2017-05-24T11:32:32.803

Reputation: 9