We know that the Apollo astronauts were subject to rigorous medical testing prior to launch, and we know that this caused at least one Apollo crew member to be replaced very late in the process.

However, what if something still happened during the actual spaceflight which prevented a crew member from fulfilling their mission role? Were there contingency plans in place for such a scenario, or was it considered unlikely enough to not warrant specific planning beyond something like "if that happens, we'll just grab the backup crew member, drop them in a chair next to CAPCOM and say 'sort this out'"?

It has been claimed that the Apollo CM was designed such that the command module pilot alone could fly the CSM back to Earth in the event that the lunar-landing mission failed. Given that the CSM was completely separate during the lunar-landing phase of the mission, that makes very good sense; lots of things could go wrong during that phase of the mission, and losing two astronauts was less bad compared to losing three.

Was the lunar module designed and the people involved trained similarly, such that in the event of a crew member problem among the lunar landing crew while on the lunar surface, either lunar-landing astronaut (commander or lunar module pilot) could at the very least ascend from the lunar surface and execute a successful rendezvous with the manned command module?

The inspiration for this question was a comment by Anthony X, which doesn't appear to have received any followup.

  • $\begingroup$ ibiblio.org/apollo/Documents/… $\endgroup$ Commented Sep 26, 2014 at 12:08
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    $\begingroup$ @DeerHunter That's a 974 page PDF made up of scanned images, not searchable. While it might answer the question, a slightly more specific reference would be appreciated :) $\endgroup$
    – user
    Commented Sep 26, 2014 at 12:11
  • $\begingroup$ Was working through... will report once found. $\endgroup$ Commented Sep 26, 2014 at 13:26

2 Answers 2


General answer: Yes, but the workload would have been high, and the ability to deal with problems would have been compromised.

The lunar ascent and rendezvous was mostly automatic, and the main job of the crew (apart from some sequencing steps) was to carefully monitor the process, comparing progress of various parameters to paper charts and be ready to take action in the event of a fault.


I expect it was quite possible. Any planned stage after One of Three suddenly drops dead would have been summarily cancelled and the remaining crew would do whatever mission-abort step was suitable at the time. Sometimes this involved doing absolutely nothing.

The CSM was certainly able to return with one crew aboard, and they must have considered Plan B lunar ascents - there was a real chance that one of them would have a fatal accident on the lunar surface. Punch a reasonable-size hole in your suit and there's no way you will get back into the LM, close the door and pump it back up before you are out of air.


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