Digest Number 52

In a message dated 3/23/01 10:40:18 PM Eastern Standard Time,
jonlennart.beck@... writes:

In the argument of which comes first - go to Mars or Develop Near
> Earth resources - I think Mike Combs hit the nail on the head in one
> of his previous postings when he said:-
In the argument of which comes first - Mars or orbital industries
near Earth - I have an additional argument against the former:
biocontamination. If we land people on Mars, it is virtually certain
that microorganisms from Earth will be released onto the Martian
surface, unless so draconian measures are used against that contingency
that it would be far cheaper with unmanned landers anyway. It's
possible that these microbes all die anyway, but it's not certain. And
if we later discover microbial life somewhere under a rock or beneath
the sediments, we may be hard put to determine if that is indigenous
Mars-life or something we brought there. >>

Truly alien life would definitely have an alien signature, it wouldn't have
DNA, RNA, and probably wouldn't metabolize the same sugars we do. Then there
is the Panspermia theory, namely that a piece of Mars was knocked off by an
asteroid impact and contaminated Earth, or a piece of Earth got knocked off
by an asteroid and contaminated Mars. In either case the life found on Mars
wouldn't be truly alien although its likely that it would have evolved since
the contamination began, in that case you could tell the native Martian life
from those microbes brought by astronauts by the fact that the native martian
life would be better adapted to the Martian environment than would be the
case from recent Earth imports.

<< This has been a regular
concern when dropping probes before - the Viking probes were thoroughly
sterilized, and there was concern that the probe that entered Jupiter
was not.
Remember that humanity is now in an excellent position to totally
screw up our chances of finding out if there is indigenous life on Mars,
and in the Jovian atmosphere and below the Europan ice crust for that
matter. All we have to do is put some unsterilized object there --- >>

Too late for Jupiter.

<< Rather, I imagine the Mars exploration to go somewhat like this:
First, orbital industries are established, with whatever combination
of lunar and asteroidal resources we find best. Space habitats of
increasing size are built. A space habitat has an engine tacked onto
it, and is sent to Mars orbit. From this permanent orbital base, Mars
is observed remotely and with sterilized landers, until we know with
reasonable certainty whether there is Martian life. >>

You want to send a city ship over to explore Mars for the first time with
space probes? In maybe 50 to 75 years after the Island Threes are built? You
might as well talk about exploring Alpha Centauri by spaceship, I'll be just
as dead then as I would when we finally explore Mars by city ship under your
plan.

<< If we discover that there is none, we lift the quarantine.

Jon L. Beck.
>>

We can only confirm the existance of life if there is any, not its absence if
there isn't. There is just too much of Mars to sift through and too many
places life can hide. We'd have to completely rearrange the surface of Mars
and turn its crust inside out by remote probes crontrolled by your orbiting
city ship, and even then we could break open a rock and not find any life but
how do we know that all the life is bunched up on one side of the rock and
completely contained in the half rock that remains after we broke the rock in
two? If life isn't under this rock, it could be under that rock, etc. etc.
How do you know when there is no life on Mars, and is finding out worth this
much trouble? How do we know the probes have been completely sterilized?
Perhaps there is a form of life on Earth that can survive the conditions that
we think could kill all life on the probe. These conditions are impossible to
fulfill.

I'm much more interested in whats in the Solar System than in what you can do
in orbit. If were going to go into space I'd much rather explore the planets
that are there, than just hangout in orbit. Sure weightlessness is a novelty
at first, but then it gets boring as all novelties wear off. I like to
explore new places, that is what attracts me to colonizing the Solar System.
Space Colonies may be great places to live, but don't say, "Hands off the
planets!"

Tom Kalbfus