I have looked for quite a while to find this out, and as yet have not been able to work out the answer.

On the Apollo missions 10 to 17 the CSM had to turn round to pick up the lunar module between leaving the Earth orbit and the moon orbit. The CSM would depart from the lunar orbit module, travel out "some distance", then do a 180 degree flip and pick up the lunar lander craft. In the cartoon style pictures, it looks like it is done immediately, however I can't imagine that would work easily!

So how far out - in feet or metres - did the CSM travel before turning round? Was it the same for all missions, or was it different for each one?


1 Answer 1


It varied from mission to mission: they started out conservatively, reducing the separation distance as they gained experience:-

The Apollo 10 flight plan details the Transposition & Docking manoeuvre on page 3-7:

Apollo 10 flight plan page 3-7

The separation in +X is done a 0.8 feet per second for 35 seconds, hence the total separation is about 28 feet, or 8.53 meters.

The Apollo 11 flight plan details the Transposition & Docking manoeuvre on page 3-4: Apollo 11 flight plan page 3-4

The separation in +X is done a 0.8 feet per second for 15 seconds, hence the total separation is only about 12 feet, or 3.66 meters.

For Apollo 17 (page 3-5), it was even less: 15 seconds at 0.5 feet per second totalling 7.5 feet or 2.29 meters: Apollo 17 flight plan page 3-5

Actual distances are a bit shorter probably, because the velocity is not instantaneously attained.

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    $\begingroup$ For the "total separation" - The separation continued during the pitch mnvr so you should add the (time to rotate 180 deg) * (sep velocity) $\endgroup$ Nov 16, 2021 at 13:21
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    $\begingroup$ @OrganicMarble I was wondering about that; not sure how to interpret the numbers exactly. F.e.: for A10 and A11 they seem thrust in -X already before pitching, while for for A17 it appears maybe simultaneous...? At 0.5 deg/sec the flip takes 360s, which would take them out another 300 feet almost, that is a lot more. The whole T&D is scheduled for 10 minutes, so they can't go that far out... $\endgroup$
    – Ludo
    Nov 16, 2021 at 14:10
  • $\begingroup$ Yeah, I was just going by what is shown on the Apollo 17 procedure; it shows translation null after the pitch maneuver, - unless the "V49 AUTO MNVR" nulls it. $\endgroup$ Nov 16, 2021 at 14:19

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