On 2005-08-11, TVDad Jim wrote:

How do four astronauts on the Moon make it a "better" mission than
three astronauts on the Moon? It sounds like a lot of ballast (both in
body mass and support materiel) to land and re-launch.

Four people means you can potentially operate two teams of two, which
allows for more activity to be done within the limited surface time
(since you're not constrained by things like daylight, which helps). If
you just have three people on the surface, then you're effectively
limited to one operating team, since you wouldn't want anyone to be
working solo if possible.

One of the major advantages of having a CMP in Apollo was that he could
do "orbital work" - photographing landing sites, that sort of thing -
whilst he was on his own. A lot more of this "routine science" can be
automated now, lessening the requirement for a human in the loop. A CEV
is also likely to be a lot less "maintainable" than a CSM was, meaning
that fewer potential problems would be helped by having a person handy.

It actually reads a lot like the current Mars Reference Mission -
lander, unmanned orbiting return vehicle - in some respects, and I
suspect there may have been cross-pollination of ideas there.

Also, consider longer missions - a solo flight for the *CMP is fine for
a few days, but once it stretches to significantly longer than that
he'll be bouncing off the walls, which may adversely impact the mission.

--
-Andrew Gray