Mars and Island One

Hi Mike,

Read through your interesting reference. I am not against free-floating habs. All I am saying is that putting up some kind of hab on Moon or Mars will be easier in the *Near Future*.

1. You arrive on Moon or Mars, if the food is imported from Earth as Andy suggests it will be for the coming 25 years, then all you have to do is to burry your hab under the soil, you immediately solve the radiation problem, and you are more or less comfortable.

2. If you have the technology and the machinery to process ores in space, well, a fraction of that technology is sufficient to put up a more modest hab on Moon or Mars. In the near future, before terraforming is made possible (on Mars), a sealed environment will be necessary for agriculture whether we have the facility in space or on Moon and Mars. It will be simpler to set up the facility on Moon or Mars. I think we are underestimating the difficulty inherent in working is space. (The cumbersome way in which Astronauts do their space walks, and the recent dropping of plans to upgrade the Space Telescope using the Space Shuttle underscores the difficulty.)

3. In any case, if the resources of the Moon are going to be used to make a giant space hab, it makes sense to put up a settlement on the Moon to start with.

4. G of 0.38 on Mars seems to be good enough. If the space suit permits good freedom of movement, jumping and running on Mars should keep a man healthy. (Someone who has worn a space suit can comment on this!)

5. With all the concerns raised regarding terrorist attacks on Earth - with habs in Earth and Moon orbits being used as kinetic energy weapons - will it be better to build free floating habs in Mars orbit?

6. In the near future we have to get people interested in Space. Apparently 40% of Americans believe in the creation theory and with various religions and cults taking human intelligence for a ride, this is going to be a difficult task. Putting up a modest operation on Mars with say a hundred people will ignite the mind of the young and eventually make large free floating space habs possible.

Regards
Selvaraj.

From: Combs, Mike
To: spacesettlers@yahoogroups.com
Sent: Wednesday, April 07, 2004 6:39 PM
Subject: RE: [spacesettlers] Re: Mars and Island One

From: sraj [mailto:sraj@...]

> The problem I feel boils down to whether or not there will be some
kind of agricultural activity in space.

I agree with you that agriculture is an important point that these
arguments turn on.

> If any
> agricultural activity is planned to support even say 20 people, very
large space habs will be required. With the
> available resources - during the next 50 years let us say - will it be
easier to set up such habs on Moon and Mars or
> have free floating complexes? My suspicion is, it will be easier to
set up such habs on Moon or Mars.

I'm aware that this is a very common assumption, but can you defend it?
Is it borne of a careful, numerical comparison of these locations on a
level playing field, or a gut-level bias?

The sole advantage for Mars that I can see is that the resources needed
are literally underfoot, and can be imported via methods not involving
space travel (though it's arguably still more difficult than shipping
things around here on Earth). But in order for Mars or the moon to
trump orbital locations, this single fact must outweigh all these points
together: http://members.aol.com/oscarcombs/spacsetl.htm#advantages

> And since there is
> more likelihood of obtaining water freely on Mars, are the Mars
enthusiasts right after all? Mars also has gravity of
> 0.38 of that on Earth - very important.

This is actually a disadvantage. For one thing, it's the wrong amount
of gravity; we don't yet know that this level will keep us healthy
long-term. Orbital habitats can spin for a full 1-G; the only level we
can know for a fact won't have long-term health issues. On the other
hand, on Mars the gravity is there all the time, and cannot be turned
off when inconvenient. In an orbital habitat, one could have rotating
and non-rotating structures. Any process which might benefit from 0-G
can be placed in the non-rotating section. We'll be able to build
enormous-yet-flimsy structures in orbit which won't be practical on Mars
due to gravity.

> Free floating structures will require radii of about a mile to achieve

> significant g levels. Are O'Neil type structures too futuristic for
the immediate future?

If 2 RPMs turn out to be OK for most people, we could get by with radii
significantly below a mile. But even if we're limited to 1 RPM, the
first habitats to provide Earthlike levels of gravity might indeed
require radii of about a mile, but may be built like a dumbbell. Such a
structure could house a much more modest crew than either a Bernal
Sphere or a Stanford Torus, and would mass a lot less.

Regards,

Mike Combs