John Schilling wrote:
In article , Sea Wasp says...


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.


s/can/must

Exploring Mars means, your e.g. water reclamation unit has to work or
you die. Exploring the Moon means, your water reclamation unit should
work or you have to go home and come back later.

Only if THAT is the disaster you are postulating. You can't postulate
"undefined disaster", and then specify one that's necessarily worse on
one end than the other. What about "lose 90% of your breathing
supply"? That would be lethal -- and nonrecoverable -- on the Moon,
but on the postulated Mars mission it's just a PITA.




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


Aren't I entitled to assume identical, or at least similar, equipment?

No, because the voyage requirements are different.


Your claim is that exploring Mars is roughly as easy as exploring the
Moon.

Yes and no. My claim is that the two are relatively equally
reachable. More supplies does translate to more COST, but not more
technical difficulty. My other claim is that there's much more
worthwhile to use/get ON Mars than there is on the Moon, such that
it's not really worthwhile to GO to the Moon if your actual intent is
to end up on Mars. I.e., the Moon is NOT a stepping-stone to Mars,
it's a side trip with no real use.


If exploring Mars requires, to ensure safe return, many tons
of expensive, exotic equipment that must work right, whereas the Lunar
case requires a duffle bag full of gear that I can buy at my local
boat & dive shop, then exploring Mars is not as easy as exploring the
Moon.

Fortunate that this is not the case. The "expensive exotic equipment"
is overall less technically demanding to create than most of the
equipment that comes standard in the Shuttle.

MORE stuff, yes. More bizarre, cutting-edge stuff, no. I would
contend that exploring Hawaii is roughly as easy as exploring
Antarctica (assuming, say, 1950s tech but no aircraft), if I'm
starting off from Tierra Del Fuego and have to not resupply on the
way, and only use either what I find when I get there, or what I sent
ahead of me, or what I brought along. Hawaii is much farther away, and
while I can use the same general technology to get there, I'd better
bring a lot more stuff along. And if something goes badly wrong, I
could die in either place. If it's something that I cannot find a
solution for locally, I probably have a better chance of rescue in
Antarctica, if it's not immediately lethal, as the rescue mission will
get there a lot quicker. On the other hand, I'm more likely to find
a solution locally on Hawaii than Antarctica.

(Note that I am *NOT* saying that either of those places is in
actuality equivalent to either the Moon or Mars, both of which are
much more hostile)


Your hypothesis explicitly requires that exploring Mars and the Moon
require similar kinds and ammounts of equipment.

Kinds. Not amounts.


Equal in probability of success, or at least survival, but very *different*
in the ammount of effort required to achieve that probability of success
or survival.

Making the one harder than the other.

Only in certain ways, and not even in all the ways one necessarily
assumes.




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.


What, you're only planning to go to Mars, *once*?

OK, you're a Zubrin fan, so if you go to Mars at all it will only be once,
maybe twice.

Huh? You're making no sense at all here. Zubrin's goal is ongoing
exploration and eventual colonization. Dozens, even hundreds of trips.


But if you're going to stay, there's always going to be a
next mission gearing up, a ship that can be retasked for emergency rescue
at need.

Um, not in the timeframe we're talking about. Or are you going to
contend that we could have gotten another Saturn 5 set up and launched
in 3 days if one of the Apollos had gone funky? They weren't set up
THAT fast.

If your mission is months long, and something goes wrong toward the
END of those months, yeah, probably there's another mission on the
way, or close to on the way. But not on average, until you get to the
"interplanetary travel as routine" stage in which case we're in a very
different kind of situation.


--
Sea Wasp
/^\
;;;
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