Let's assume that all the resources to get back to Earth can be made on
Mars. Big deal, that breaks the trip into one-way trips to Mars and from
Mars. Each of those is still over eighty times the distance of the Lunar
round trip.

"Sea Wasp" wrote in message
...

Not really. It does depend on the assumptions you make, true, but you
exaggerate a number of issues. Mars offers opportunities to support
your marooned astronauts, assuming they brought the right equipment,
which the Moon does not. There are reasonable ways for them to make
air and water from what's there, as opposed to the Moon, where you
really CAN'T do that unless you happen to be incredibly lucky about
what you bring and where you land. You can make fuel on Mars a lot
more easily than you can make it on the Moon.

If you assume each one starts with IDENTICAL equipment -- and that
the equipment in both cases is optimised for the Moon -- then hell
yeah, the Mars group is screwed.

If you assume they each start out with optimal equipment for the
mission in question, they should be roughly equal.

If you insist on analogies on Earth, it's the difference between
sending your Boy Scout troop to Antarctica from a ship anchored
several miles offshore (but not reachable in any way over the ice,
etc.) and sending the exact same Boy Scout troop there from New York,
and the Troop in question has to be self sufficient from the time they
leave until the time they return.

If you assume the Troops in both cases have only the supplies for the
short trip, then the long-trip one is screwed. If you assume the
long-trip ones expend planning and effort to make sure additional
supplies are there, they aren't screwed.

If you can get people there for colonization or research or whatever,
you can also send, ahead of them, an equivalent or greater mass of
supplies (especially since the supplies sent to mars can (A) use
aerobraking to assist in the slowing down and landing, which the Moon
ones can't, and (B) don't have to return, so the entire mass only has
to be able to land, not take off. Read Zubrin for the details on this
process.

The KEY point about BOTH of them is that it is a nontrivial effort to
mount a rescue mission unless (in both cases) you have such a mission
STANDING BY. To just throw together something that would reach the
moon with sufficient capacity to go down, retrieve your astronauts,
and come back home safely is, likely, somewhat cheaper, and certainly
faster, than doing the same for Mars. However, in BOTH cases you have
already established the technology to actually accomplish the
objective, and if you were reasonably forward-thinking would make
allowances in supplies to deal with unforeseen events that somehow (by
great good fortune) left the astronauts in question alive.

The only *material* difference, as far as I see, is time; if you
assume they have only enough food for, say, a few weeks, yep, Mars is
screwed (fastest reasonable transit, given the right tech and right
orbital parameters, is about 3 months). Mars has water, and if they
brought the appropriate gadgets they can manage to keep up on the
water/air equation, but food isn't something you can make out of raw
materials yet.




--
Sea Wasp
/^\
;;;
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