Re: How to really terraform (part 1)

From: quibbler (quibbler247_at_yahoo.com)
Date: 06/14/04 

Date: Mon, 14 Jun 2004 17:29:20 -0600

In article <pan.2004.06.14.20.49.36.841598@hotmail.com>,
khallow@hotmail.com says...

> I wonder though if it'll turn out to be cheaper to build insulated pipes
> carrying liquid water

One could probably build the pipeline from insulative materials like
fiberglass. Of course one could use foam insulators and even vacuum
cavities too, though this would get expensive. A more cost effective
solution would be to partially bury the pipeline or to pile up large
dirt/rock berms on top of the pipe. As a coup de grace one could color
the surface of the berm black to help absorb solar heat during the day.

> The coldest temperatures experienced along the Alaska pipeline were
> roughly -60C (-79.8F) while the Martian poles routinely reach -140C.

Yes, but the Trans Alaska PipeLine is above ground in many places,
whereas this could be covered by meters of insulative material. If
necessary one could build heating elements into the pipeline, inside the
insulator jackets. For that matter, since water is a polar molecule,
you could use alternating magnetic fields to heat it in much the same
way that a microwave oven operates.

> A final significant point is that petroleum has a high usable energy
> content. So part of the fluid can be burned to generate heat and energy to
> keep the fluid warm and pump it onwards. I don't know the energy budget
> for the pipeline,

Very roughly the estimate was 40,000 cubic feet per second of water.
I'd estimate that we'd need this to be moving at about 40-50 ft/sec to
have a reasonably sized pipeline. Given that water is about 60 lb/cu
ft, were looking at in excess of 120 million foot pounds/second or about
160 MW/s continuous, neglecting issues like friction and assuming that
my back of the envelope calculation isn't otherwise flawed. Assuming
that inefficiencies and other factors don't drive it up by more than a
factor of 3 or 4 then it should be the kind of energy that a moderately
sized nuclear reactor on earth could supply.

> ie, how the infrastructure is powered, but there's some
> obvious ways to power Earth-based petroleum pipelines that wouldn't apply
> to water pipelines on Mars.

One means which shouldn't be overlooked is a salinity gradient turbine.
These devices use osmotic pressure differences between fresh water and
brine to produce energy. Since the MERs have established that there are
likely to large salt and brine deposits on mars, salinity gradient
energy would probably be pretty viable. It would also end up combining
the water with salts and making them less vulnerable to freezing in the
process. 

-- 
      Quibbler (quibbler247atyahoo.com)
"It is fashionable to wax apocalyptic about the 
threat to humanity posed by the AIDS virus, 'mad cow'
disease, and many others, but I think a case can be 
made that faith is one of the world's great evils, 
comparable to the smallpox virus but harder to 
eradicate."  -- Richard Dawkins

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