Re: Retained LM ascent stage

In article <1146186788.862554.128570@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
John Charles <johnbcharles@xxxxxxxxxxxxxx> wrote:
But you raise an interesting question: why was the EVA done after TEI
and not before it, still in lunar orbit?

Don't think I've ever seen this addressed. However, I think I can guess.

In terms of the spacewalk itself, there's no obvious reason to prefer one
time or the other. But there's plenty of time between TEI and reentry
when the crew don't really have a lot to do, so that's the obvious time.
To make time for it in lunar orbit, you'd either have to end science
operations early, or delay TEI.

Moreover, doing it in lunar orbit would insert a complicated procedure,
which expends a lot of time, effort, and oxygen, *before* a critical
maneuver. Better to do the absolutely-vital maneuver first, and then,
when that's successfully completed and assorted contingency plans are no
longer needed, look after the desirable-but-not-essential spacewalk.
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