I was looking at some diagrams for the Apollo spacecraft, which I found to be interesting. It's clear that there's two separate enclosures that astronauts could reside in (the lunar module and command module). However, there is a massive rocket nozzle in between each habitable enclosure. This leads me to a few related questions.

Where and what kind of design was in place to allow the astronauts to safely move from enclosure to enclosure? How did the astronauts traverse them? Were there any restrictions? What sort of precautions and safety mechanisms were in place to keep the astronauts safe when a lower section of the craft was discarded through the various stages?

enter image description here

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    $\begingroup$ The Soviet Moon program planned to save mass by instead having the cosmonaut spacewalk between the corresponding two modules. $\endgroup$
    – LocalFluff
    Commented Dec 8, 2014 at 10:57
  • $\begingroup$ This excellent animation shows how the docking mechanism worked. $\endgroup$
    – John Bode
    Commented Nov 21, 2021 at 13:39

1 Answer 1


The launch escape system was jettisoned after launch. Here is a picture of it being tested:

enter image description here

With the launch escape system out of the way, and the fairings released, the crew performed a transposition and docking maneuver on the way to the moon.

It was performed by the Command Module pilot (although, as a contingency, the Lunar Module pilot and commander were also trained to perform the maneuver), and involved separating the CSM from the S-IVB, pitching the CSM 180° and proceeding to dock with the Lunar Module, by inserting a probe at the top of the CSM into a drogue at the top of the Lunar Module. Then, the Apollo spacecraft stack would separate from the S-IVB, which would then either continue on to a heliocentric orbit or be deliberately steered into a crash landing on the Moon.

enter image description here

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    $\begingroup$ The Launch Abort System (LAS) isn't habitable. It just yanks the command module off the top of the S-V stack if something goes wrong early in the flight. $\endgroup$
    – Erik
    Commented Dec 8, 2014 at 6:52
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    $\begingroup$ Ah. So it's just essentially a rocket to provide thrust for the command module? Interesting. $\endgroup$
    – Ellesedil
    Commented Dec 8, 2014 at 6:55
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    $\begingroup$ @Ellesedil Yup. Idea of LES is that its safer to be strapped to bottom of tiny flaming rocket than being stuck on top of much bigger exploding one. According to Wiki it was used only once for its intended task and although it worked crew was close to becoming marmalade (14-17g, ouch). $\endgroup$
    – PTwr
    Commented Dec 8, 2014 at 10:44
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    $\begingroup$ The movie "Apollo 13" showed this maneuver very clearly. youtube.com/watch?v=Tefgq4q372Y CMP John Swigert performed it, though the docking probe scraped against the side of the drogue before securely docking to the LM. $\endgroup$ Commented Dec 8, 2014 at 14:40
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    $\begingroup$ @PTwr It should be noted that the only "in anger" use of a Launch Escape System was on a Soviet Soyuz launch. It was never used in the Apollo program, though it was tested on the unpiloted A-004. $\endgroup$ Commented Dec 8, 2014 at 19:16

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