Re: How to really terraform (part 1)

From: Karl Hallowell (khallow_at_hotmail.com)
Date: 06/14/04 

Date: Mon, 14 Jun 2004 13:49:38 -0700

On Sun, 13 Jun 2004 16:00:17 +0000, TKalbfus wrote:

> <"We must transport that amount of ice from the poles to the equator,
> forever.
> If we build solar-powered trucks that can carry 200 Klb ice, and these
> can make one round trip every 40 days (this is a speed of 10-12 mph
> average), then they deliver 5 Klb/d. We would then need 80 million such
> trucks.">
>
> We could instead build a pipeline from the poles to the equator, use
> solar power to split the water into hydrogen and oxygen, release the
> oxygen and transport the hydrogen via the pipeline to the equator, Then
> we separate oxygen from the local rocks and combine it with hydrogen to
> make water. You see it would be easier to send hydrogen through the
> pipelines than water as the hydrogen won't freeze.

I wonder though if it'll turn out to be cheaper to build insulated pipes
carrying liquid water than pipes that transport hydrogen. I'm thinking
here that liquid water is much denser per unit of hydrogen than gaseous
hydrogen under pressure. Further, the energy balance is better since one
isn't performing hydrolysis.

>From our experiences pumping petroleum products through artic tundra (done
both in Alaska and Siberia) seems to indicate that this can be done. For
example, the Alaskan pipeline moves somewhere between half a billion to a
billion barrels a year (I think the theoretical maximum is crudely 750
million barrels per year from some blurbs I read, but that historically
the pipeline averages around 500 million barrels a year). If that were
water, then it would be at least 100 billion liters (around 200 billion
lbs) of water a year. The pipeline is 800 miles long (almost 1300 km)
compared to an apparent Martian distance of around 5000 miles (8000 km).
That's six times longer.

The coldest temperatures experienced along the Alaska pipeline were
roughly -60C (-79.8F) while the Martian poles routinely reach -140C.
That's significantly colder (eg, CO2 freezes at those temperatures). The
temperature of the petroleum running through the Alaskan pipeline is on
average 60C (140F) (and I gather the starting temperature is 160F or
roughly 70C) while we might get away with a 10C or 20C fluid on Mars
(possibly a little lower by adding some sort of salt to the solution?). So
in comparison, the Alaskan pipeline has to handle maximum temperature
differences of up to 120C between fluid in the pipeline and the
surrounding environment.

In comparison, on Mars you might have to deal with 160C (or worse)
temperature differences. Significantly more challenging for a host of
reasons, but seems to me that it's a case of pushing the envelope on well
established technology.

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, 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. IMHO, the discussion in this thread about how
to power movement of water and other materials is well placed.

Karl Hallowell
khallow@hotmail.com

Quantcast