Re: ISS as Mars vehicle

From: Bill the Cat (bill_at_the.cat.retro.com)
Date: 12/14/04 

Date: Tue, 14 Dec 2004 00:05:24 -0600
To: sci-space-tech@moderators.isc.org

"Kent Paul Dolan" <xanthian@well.com> wrote in
news:f0226bf8106c8c9a2ea844299f0ee68d_48257@mygate.mailgate.org:

> I'm guessing this has been discussed before, but
> with the new initiatives on solar sails and ion
> propulsion drives, humor me anyway.
>
> As opposed to trying to orbit and proof an entire
> new Mars mission from scratch, what would be the
> benefits and disbenefits of adding stuff to the ISS,
> dragging it all off to Mars using a continuous
> propulsion system of one sort or other (or perhaps
> several), and using it like the lunar orbiter as a
> staging base to and from the Mars surface?
>
> The main advantages I can see is that it is already a
> known-to-be-functional long time habitat for humans,
> and that it is a huge amount of mass already much of
> the way out of the gravity Earth's well.
>
> But, is it strong enough to survive being shoved?

Not if you use conventional propulsion. ISS is quite flimsy from a
conventional structures point of view; it's very much designed for a zero-g
environment. The fuel required would be colossal anyway; you'd need the
equivalent of four S-IVB stages for the job.

On the other hand, with low-thrust propulsion, ISS would have to spend a
long time spiraling out through the Van Allen belts, which would certainly
fry the electronics (not to mention the crew, if you're fool enough to
leave one onboard during the boost).

> Is it reliable enough not to need the possibility of
> a quick rescue everytime someone miscalculates the
> inhabitant's appetites?

No, not even close. Read up on the recent troubles with ISS's oxygen
generator, for example.

Then there's the fact that ISS's thermal control system is quite
specifically designed for LEO, and would run into lots of problems once
there's no longer a nice warm Earth filling almost half the sky.

Then there's the fact that ISS needs regular Progress resupply flights,
which will no longer be able to reach it once it leaves LEO.

> Consider also building up from the present
> capability to include such needed stuff as
> self-sufficient hydroponics and full waste
> recycling, with a long term _intention_ of shoving
> the whole mess, once it can serve, as a planet to
> planet "wanderer" (pun very much intended).

You're halfway on the right track here: the best use of ISS in a manned
Moon/Mars exploration program is as a lab and testbed: to determine the
best biological countermeasures to keep the crew healthy on long trips, and
to test prototype systems for future spaceships for reliability. But moving
ISS itself out of LEO is folly.

Relevant Pages

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