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Old August 31st 18, 01:55 AM posted to sci.space.science
Thomas Koenig
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Posts: 47
Default Make vs. buy for a Martian colony

Alain Fournier schrieb:

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.


Making a smelter isn't all that easy, and even so, will the material
you produce actually be useful for anything?

The colonists will probably have to make steel if it is to be used
for anything useful, so you have a two-step process already.

The material should probably withstand the cold on Mars, it will have
to be austenitic steel. So, be ready to alloy it with Nickel,
Chromium and Molybdenum. You may be in luck finding Iron Nickel
metorites on Mars...

Then, have your factory ready to convert this into bar stock.
Next, it goes into the workshop.

Unfortunately, machining austenitic steel is quite difficult.
You need excellent tools and lots and lots of cutting fluid,
which needs to be pumped around. This, of course, needs pumps and
gaskets and... Also, you tools will of course wear out. So,
before you try to machine Austenite, better have your tool
steel production up and running... and make sure to get that
Carbon content right, or you will not succeed. Also, of
course, you'll need the hardeing...

Good thing that the lubricants for the machine tools have already
been manufactured, from the lubricant factory that was set up
before the first ever machine shop ran out of lubricants that
the colonists brought with them.

By the way, if the bearings on your mill break, did you stock enough
spares? Or are you going to set up a ball bearing production?

Etc, etc...

Long story, cut short: I see little problem getting a colony up
to ~ 1850 tech. But that is not going to help a lot in helping
survival on Mars.

At the moment, around 7700 chemicals are produced

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.


How many people do you think would be required for that?

So maybe your rubber O-ring which needs so
much infrastructure to make could be replaced by a much easier to make
O-ring.


"Maybe" is not good enough in this case.

What other material do you propose for an oil-resistant gasket?

Polychloroprene? Chlorinated Polyethylene? Nitrile rubber (well,
we had that one already)? Polyurethanes? Silicone?

There is no simple way to make an oil-resistant gasket. Each and
every method known to us needs many chemicals, and very many complex
processes that took decades and decades to bootstrap here on Earth.

And really, that gasket was only a random example of something
that we take for granted on Earth - just order it.

Take a look at what the moon spacesuits had for materials, then try
to come up with the supply chain for each of those. And please
don't skimp on the material quality, nor the UV absorber, of the
Polycarbonate helmet bubble. It's no fun wearing a spacesuit if
the helmet becomes brittle and starts cracking under UV radiation
while you are outside...