From: Bruce Dunn <bpdunn@home.com>
Newsgroups: sci.space.tech
Subject: Re: Mars S Pole conditions
Date: Sat, 24 Jun 2000 05:07:39 GMT

Geoffrey Landis has provided a nicely developed set of arguments for
initial landings at the Martian poles.  For any sort of permanent
habitation, the polar ice might be a useful resource for colonies in
more equatorial latitudes.

As described in Geoffrey's paper, the constant sunlight at the poles
during their summers allows energy intensive extraction of hydrogen from
water.  With hydrogen, a chemical plant can make ethylene using CO2 from
the atmosphere.  Ethylene can be turned into polyethylene which can in
turn be used to make a pipeline from the poles to the equator.

A water pipeline offers severe problems in keeping the water from
freezing.  However, hydrogen (the basis for making water, and an
incredibly important resource in its own right) can easily be
transmitted through un-insulated pipelines.

One can envision a mobile chemical plant, which starts at the pole and
works its way overland to equatorial colonies, laying a hydrogen
pipeline as it goes.  The pipe is make of polyethylene, synthesized on
the spot from CO2 and from hydrogen flowing down the portion of the
pipeline already constructed.  The hydrogen pipeline operates at ambient
temperature without insulation, a feat impossible for a water pipeline
from the poles.  At the equatorial colony, the hydrogen can be used in a
variety of roles, displacing hydrogen which otherwise would have to be
manufactured from local water.  Some processes, such as the direct
reduction of iron ore by hydrogen to give iron for structural uses,
generate water as a byproduct.  The importation of polar hydrogen in
these cases amounts to the importation of polar water, without having to
deal with the problems of operating a water pipeline in a frozen
environment.

This pipeline strategy will not be needed if reasonably accessible water
is found to be available in areas which are best suited to
colonization.  However, if local water is hard to find or hard to
extract, hydrogen pipelines to one or both poles might be very useful.

"Geoffrey A. Landis" wrote:

>
> I wrote a paper once discussing the Martian poles as landing sites for a
> first mission; it has some background information of the type you might
> want-- the short version is at
> http://www.sff.net/people/Geoffrey.Landis/pole.html

From: Bruce Dunn <bpdunn@home.com>
Newsgroups: sci.space.tech
Subject: Martian Hydrogen Pipeline
Date: Mon, 26 Jun 2000 00:09:29 GMT

James Graves wrote:

> However, I was under the impression (and please correct me if I'm wrong)
> that hydrogen gas can leak out through some kinds of plastics.  I
> wouldn't think that polyethylene would be dense enough for something
> like H2.

I don't have any direct data, but I expect that the permability of
hydrogen through cold polyethylene is low enough that the losses of
hydrogen would be insignificant.

> Maybe make the methane there, and ship that through the pipeline instead.

It could be done.  However, hydrogen is much more useful in a colony, as
it is a more universal starting point for chemical reactions.  If the
colony needs methane, it can make it as needed with pipeline hydrogen
from solar powered electrolysis units at the poles.  Other hydrogen
would be used for iron ore reduction or ethylene production (which
requires H2 and CO2, but does not involve using CH4).  Shipping only the
starting material to the colony leaves all the chemical plants at the
colony, with the exception of the hydrogen production system.


In addition to hydrogen, it might be worth shipping the oxygen generated
by the electrolysis, using a parallel pipeline.  At the colony, the two
gasses would be recombined in a fuel cell, recovering some of the energy
originally supplied as solar power at the poles.  The dual pipeline thus
combines the functions of a water pipeline and a power line.