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Make vs. buy for a Martian colony
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? |
#2
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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 |
#3
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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... |
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