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Old August 28th 18, 01:41 AM posted to sci.space.science
Alain Fournier[_3_]
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Default Make vs. buy for a Martian colony

On Aug/27/2018 at 3:46 PM, Thomas Koenig wrote :
Make vs. buy (where "buy" has a likely lead time of anywhere
between six months and more than two years) decisions are going
to be hard for any Martian colony that has not developed a full
industrial base comparable with what we have today on Earth.

Even something simple, like an oil-resistant nitrile rubber O-ring
gasket, would require a long chain of manufacturing, starting out
with Butadiene (which requires something like a steam cracker),
Propene and Ammonia for the monomers, plus emulsifiers for the
emulsion reaction and large amounts of water which would end
up polluted. Also, rubber manufacturing is quite a specialized
process.

This would only give you the base polymer. In any useful rubber
compound, you are likely to find 20 to 30 different chemicals, from
fillers (carbon black, silica, plasticizers), a rubber protection
system (UV, oxygen, radiation, Ozone, fatigue, ... protection),
processing aids (lubricants, tackifiers, dispersion agents,
peptizers, oil), vulcanizing agents such as sulfur or peroxides,
activators, accelerators, scorch retarders), and probably others
I have forgotten. Each of these has their own synthesis route
and supply chain.

And you will also need specialized catalysts for making many
of the materials that will have to go into that simple gasket...

All of this for a part that will cost a few cents here and now.

So, it is likely that drastic simplification will be needed
to build up an industry on Mars, both in material selection
(don't try to use the best materials available on Earth
for that spacesuit) and in processes (accept inefficiency
that would bankrupt any company on Earth today).

And don't count on a Mars colony becoming independent from
Earth supplies any time soon.

What work has been done in what a Martian colony would be able
to produce for itself, work that addresses the complexity that
I have only given a very small part of?


I would expect that at first very few things would be made locally.
Maybe only O2 from CO2 and extract small amounts of water from the
atmosphere as a by-product of getting O2. But rapidly, colonist would
want to grow their own veggies or something else. After that more and
more stuff would be made locally.

Before the first colonists arrive at Mars, they would probably have some
sort of plan about when they will start doing this and when they start
doing that. But once there, they will change the plan according to their
needs. That doesn't mean that making the plan aforetime isn't useful.
You need to know all the prerequisites before you start trying to do
something and those prerequisites aren't always completely obvious. And
if, as I said above, you want to grow veggies quite soon, maybe you
shouldn't start by building greenhouses to grow them. Maybe your
priority should be to do something else which gives a fertilizer as a
by-product. Having a plan before leaving helps to know those kind of
links. But once the colonists are aware of those links, they will decide
on their own whether having a smelter is more or less urgent than
growing coffee.

I would also expect that Martian colonists will find solutions with
maybe less performance than what we have here on Earth but have the
advantage to be easier to do. So maybe your rubber O-ring which needs so
much infrastructure to make could be replaced by a much easier to make
O-ring. Then you organize things so it can easily be replaced every
week. If that isn't possible for some particular usage, order high
quality O-rings from Earth for a few more decades.


Alain Fournier