Man-rated vs. non man-rated
I thought I'd put this here because the distinction between man-rated and non man-rated vehicles will impact everything that goes into thinking about Moon and Mars missions.
A man-rated vehicle is many times more expensive than a non-man rated vehicle. So why be foolish enough to use a man-rated vehicle to do ANYTHING other than get flesh and blood from surface to space and vice-versa (plus just enough supplies for that)? Everything else can be done by robot vehicles. We had robots landing on the moon before Apollo (surveyor) and the Soviets landed an automated sample return rocket not long after. So this is old technology and not something we can't do now, whenever we need to.
The antithesis is what killed the shuttle program: NASA made the mistake of carrying big clunky satellites in a man-rated vehicle, every flight. Eventually, this resulted in loss of crew. Twice.
Even in the Apollo mission, we wasted man-rated boost capacity, and return heat sheild capacity, carrying rocks! We had to vacuum insulate moon rocks so they wouldn't be exposed to the oxygen inside the vehicle, because they were INSIDE with the crew! How dumb is that? For larger amounts of stuff, we cannot let that happen.
So, please keep in mind: we want all major supplies and machinery and shelter to go down to the moon by robot craft. If it crashes, just send another one. No people till it's all down and working. When sending stuff back from the moon, automated sample-return is the way to do it (even more so, for Mars). Astronauts coming back from the Moon or Mars need bring nothing back but their clothing. No data (all has been sent ahead, digitally), and no samples (all have been split and gone ahead in sample return vehicles).
For humans, think small, minimal, and safe. No radiation shield needed, because time of use is only from orbit to surface, vice versa, and a few hours for Earth re-entry. An Orion without the big toilet suffices for Earth return from Mars (and for transit to the Moon). Small LEM-type stuff for all the rest. For everything else: supplies, sample rockets, digging equipment, etc, think, big, heavy, open to vacuum, unshielded also when appropriate, and robotic. For the moon, your radiation sheild is either sent ahead, constructed out of moon materials, or both. But you don't send any down with crew.
You might think all this is obvious, but I've seen proposals for stuff like having the crew landing vehicle fall on its side, to be used as part of a shelter on the surface. That's crazy. Why carry all that heavy surface-living stuff on a man-rated landing vehicle? It should ALL go down ahead, and be tested, before humans ever depart from Earth. And so on.
Think double! Two classes of rockets for everything you plan.
Steve Harris Sbharris 19:13, 5 February 2010 (UTC)