There’s a good recent book series about this by Daniel Suarez called Delta V (in the first book they process regolith from an asteroid; in the second book its on the moon; presumably the unreleased third book is on Mars).
ChuckMcM · 3h ago
Pretty neat. This would certainly make for an interesting Mars mission should SpaceX want to try it, land a lander, have the lander process regolith into iron chunks, create a pile of chunks. All good threshold goals.
What ever happened the asteroid mining folks? They have a similar problem, albeit with very little gravity and no atmosphere, but their metals are in theory worth a lot more (platinum, gold, silver, Etc.)
There was a similar idea/proposal for extracting aluminum from Lunar regolith, also a good space mission for private interests.
Once you've got basic metals you can make more interesting things, with iron you can make reinforced concrete which would be an interesting building material on Mars I suspect.
jacquesm · 44m ago
Asteroids are hit-and-miss composition wise (though you can determine quite a bit by observing them), but when they are a hit they tend to be really valuable. The problem then is that you need to get to them and then the next problem is that you need to get back to where you came from.
Both of these can hurt your ROI considerably assuming you can solve for them at all with the masses involved. They're also usually moving at a pretty good clip and are bad to set up long term for. I think until we have a long term presence in the asteroid belt that this is mostly going to be SF rather than that it will actually happen.
The product I have in mind is solar sails to be delivered to the Earth-Sun L1 point to counteract climate change. A carbonaceous chondrite asteroid is rich in volatiles to make plastic films as well as metals and stones to coat them with. The pros are:
- solar sails transport themselves without using reaction mass
- you're not competing with cheap resources on Earth to be used on Earth, rather resources from Earth transported past LEO
eliminating many of the fundamental objections to scenarios where ISRU materials get transported somewhere.
Cons are:
- a good sunshade and a good solar sail are different things
- plastic + metal solar sails seem to get corroded badly over time
- if you think the turnaround time between Earth and Mars is bad, you are talking half a decade or more to round trip parts plus a 45 minute communication delay at some times; you either need to send people with all the problems that entails or have advanced autonomy and a manned simulation platform somewhere in near-Earth or cislunar space.
I've got a good picture of what parts of the "head end" that consumes asteroid materials and turns them into reasonable chemical feedstocks looks like with the exception of how to devolatize the asteroid to begin with and where to get the storage tanks to store early offgassing before the metals line comes online. (Storage tanks are an interesting question for manufacturing since the chemical factory needs plenty of them.) I also have some idea of what the "shipyard" that builds the actual sails look like. Trouble is you probably need a Drexler machine to make spare parts and also make customized parts given that you don't really know what you're up against when it comes to the "head end" (though upper pyramid parts of the chemical factory and the shipyard can be simulated close to Earth) ... and Drexler's concept for a Drexler machine doesn't work.
lstodd · 25m ago
If you so very want some mylar over carbon fiber put up in L1, and not ever launch that from Earth then Luna is the most obviously cheap and abundant source of whatever. No need for asteroids at all. Also the comms delay is 1.25s IIRC.
I personally consider this a folly.
On the other hand, no comprehensive survey of Luna was ever done, and we target Mars or even asteroids why? I'd like some at least plausible reason for this.
It is true that Luna is halfway to Mars in dV on hohmanns. But not in time spent. Never will be.
thaumasiotes · 1h ago
> There was a similar idea/proposal for extracting aluminum from Lunar regolith, also a good space mission for private interests.
With the asteroids, I assume the idea is to bring enough platinum and gold back to Earth to offset the costs of getting them from space. That doesn't sound especially realistic, but in the right circumstances I guess it could be.
With aluminum on the moon or iron on Mars, that will never happen. You'd have to want to use those materials on location.
So what would the value be of producing aluminum on the moon?
jacquesm · 43m ago
> So what would the value be of producing aluminum on the moon?
Building more rockets? Interesting detail: there isn't enough oxygen there to cause aluminum to immediately be covered with a skin of aluminum oxide. I wonder what the energy cost of an extraction process for aluminum on the moon would be. At the same time I would hate to see the moon mined, that's one piece of common property that we should maybe try to preserve unless we have no other alternative, not just for commerce.
PaulHoule · 37m ago
The idea you see in O'Neill and other science fiction that iron is rare on the moon is bunk. There is Hematite
and Apollo astronauts brought back perfectly good Iron ore. It's true that there is lot of aluminum and titanium on the moon and a lunar economy might use that but there is enough iron that if loonies wanted to make things out of iron they could make things out of iron.
nine_k · 3h ago
In short: they just heated some (simulated) Martian dirt, and this alone was sufficient to produce liquid iron, and then liquid iron-silicon alloy. No huge quantities of carbon were required. This is quite surprising to me.
Making steel, with controlled carbon content, would be quite another challenge. Carbon is readily available on Mars, but only in the form of CO2.
PaulHoule · 2h ago
Steel has between 2% and 0.05% carbon, that's not really a lot, particularly when you consider martian colonists will want materials like sugar and polyester that have a much higher carbon content. [1]
There are numerous ways to fix carbon from CO2. If you can grow plants you can make a char out of them which what people used to use to reduce iron and add carbon as an alloying elements. There is a huge amount of research on turning CO2 into CO so that it can be mixed with H2 (then they call it syngas) and then build up larger molecules such as methane, methanol, gasoline, fats, etc.
It's not a question of being able to do it but instead doing it better, cheaper, harder, faster, ...
The funny thing about reduction of iron (and many metals) is that it can be done with either of the two ingredients of syngas, CO [2] or H2 and either way you get the oxide CO2 or H2O as a byproduct. If space colonists think that volatiles are precious they'll practice chemical cycling, turning those back into reactive CO or H. On the moon or asteroids I'm pretty sure people would think either C or H2 is precious and wouldn't waste it, I am not sure about Martians (e.g. if you can get CO2 out of the atmosphere it might not seem like a crime to vent it)
[1] people think "technology" and they think "metals" but actually a lot of what you want is made of carbon, hydrogen, oxygen and nitrogen (CHON)
[2] what a blast furnace uses
nine_k · 1h ago
Yes, the problem is likely not in getting enough carbon (though a kiloton of steel would require several tons of it), but rather having a mass production process advanced enough to precisely control it. Almost all heavy equipment would have to be bootstrapped on Mars, mostly from the inevitably subpar local materials, and ith access to energy that's worse than on Earth: no fossil fuels, no hydro-energy, much less sunlight.
PaulHoule · 55m ago
Everyone who's seriously considered space colonization has come to the same conclusion that Eric Drexler did -- you need to have some kind of system that can make absolutely everything with as small a population supporting it as possible.
You've got the problem that there's nothing that could manufactured on Mars that would be worth bringing back to Earth. If a Martian colony was dependent on Earth for anything it would expect to get its resources cut off at any time, and even if you can get spare parts and stuff from Earth the turn-around time counting the synodic period and transit time will always be several years. See
I think it could be possible with some combination of synthetic biology, fermentation, flow chemistry, 3-d printing and such. It's a good northstar for research into "advanced manufacturing" which could come in handy here on Earth.
XorNot · 41m ago
Honestly I think one of the possible premier uses of orbital (though not Martian) resources would actually be agriculture. Limiting biological contamination and maintaining sterile environments, unlike other industries, can produce a value-added product compared to the inputs.
Also there's at least a plausible mass trade off - a space borne habitat structure doesn't need to support its own weight against gravity, so you might be able to trade favorably on the launch costs (e.g. grow crops in a big inflatable dome under hydroponic conditions). Certainly it would make enforcing quarantine easier.
staticautomatic · 3h ago
Iron would be fine since there’s basically no atmosphere to oxidize it right?
dmurray · 3h ago
No, steels have 4-6x higher tensile strength (and better performance in other related properties) than raw iron. [0] They're not just preferred over iron for their corrosion resistance.
And note that even what we call "cast iron" - a material that reasonably could be preferred to steel for some industrial purposes - is an iron-carbon alloy that in fact has more carbon than steel[1].
oxidation is a chemical process, [LEO says GER] that which Loses Electrons is Oxidized, that which Gains Electrons is Reduced.
it isnt always oxygen that does this, a difference of RedOx potential allowing redistribution of electrons is all you need.
mars has a perchlorate problem thus carbon compounds are converted to carbonate via Oxidation when encountering ubiquitous perchloate mineral deposits.
its toxic to carbon based biochemical forms, and destructive to carbon materials, such as carbon fibre; carbon nanotubes; carbon steel; even a lot of keypads.
We learned it as OILRIG: oxidation is loss, reduction is gain
Yoric · 3h ago
Isn't steel also much stronger?
foota · 3h ago
Iron is a lot heavier than steel and probably weaker too (IINAMS, ask your material scientist)
aj7 · 2h ago
I have a fairly generic reaction to this.
Make metals at the top of Everest. Then we’ll talk.
adastra22 · 2h ago
You’re right, that is a generic reaction. And completely ignorant of the different chemistry, environment, and context.
ACCount37 · 3h ago
It's a given that if you're taking space exploration seriously, you need ISRU. You can't ship everything to Moon or Mars from Earth - you need to learn how to process and refine local materials.
This is the key advantage of going to Mars or Moon surface, as opposed to operating a space station. A space station exists in a vacuum. Surface bases have access to local materials.
Sadly, very few planned space missions have this kind of ambition. That recent proposal US had about putting a nuclear reactor on the Moon was at least a step in the right direction - if you're bringing an entire reactor, that means you're establishing a permanent base, complete with an industry that would generate the demand for power.
https://www.themartiangarden.com/ https://www.amazon.com/Regolith-Simulant-Authentic-Martian-R...
What ever happened the asteroid mining folks? They have a similar problem, albeit with very little gravity and no atmosphere, but their metals are in theory worth a lot more (platinum, gold, silver, Etc.)
There was a similar idea/proposal for extracting aluminum from Lunar regolith, also a good space mission for private interests.
Once you've got basic metals you can make more interesting things, with iron you can make reinforced concrete which would be an interesting building material on Mars I suspect.
Both of these can hurt your ROI considerably assuming you can solve for them at all with the masses involved. They're also usually moving at a pretty good clip and are bad to set up long term for. I think until we have a long term presence in the asteroid belt that this is mostly going to be SF rather than that it will actually happen.
there are no realistic proposals for asteroid drives ala https://en.wikipedia.org/wiki/K240
- solar sails transport themselves without using reaction mass
- you're not competing with cheap resources on Earth to be used on Earth, rather resources from Earth transported past LEO
eliminating many of the fundamental objections to scenarios where ISRU materials get transported somewhere.
Cons are:
- a good sunshade and a good solar sail are different things
- plastic + metal solar sails seem to get corroded badly over time
- if you think the turnaround time between Earth and Mars is bad, you are talking half a decade or more to round trip parts plus a 45 minute communication delay at some times; you either need to send people with all the problems that entails or have advanced autonomy and a manned simulation platform somewhere in near-Earth or cislunar space.
I've got a good picture of what parts of the "head end" that consumes asteroid materials and turns them into reasonable chemical feedstocks looks like with the exception of how to devolatize the asteroid to begin with and where to get the storage tanks to store early offgassing before the metals line comes online. (Storage tanks are an interesting question for manufacturing since the chemical factory needs plenty of them.) I also have some idea of what the "shipyard" that builds the actual sails look like. Trouble is you probably need a Drexler machine to make spare parts and also make customized parts given that you don't really know what you're up against when it comes to the "head end" (though upper pyramid parts of the chemical factory and the shipyard can be simulated close to Earth) ... and Drexler's concept for a Drexler machine doesn't work.
I personally consider this a folly.
On the other hand, no comprehensive survey of Luna was ever done, and we target Mars or even asteroids why? I'd like some at least plausible reason for this.
It is true that Luna is halfway to Mars in dV on hohmanns. But not in time spent. Never will be.
With the asteroids, I assume the idea is to bring enough platinum and gold back to Earth to offset the costs of getting them from space. That doesn't sound especially realistic, but in the right circumstances I guess it could be.
With aluminum on the moon or iron on Mars, that will never happen. You'd have to want to use those materials on location.
So what would the value be of producing aluminum on the moon?
Building more rockets? Interesting detail: there isn't enough oxygen there to cause aluminum to immediately be covered with a skin of aluminum oxide. I wonder what the energy cost of an extraction process for aluminum on the moon would be. At the same time I would hate to see the moon mined, that's one piece of common property that we should maybe try to preserve unless we have no other alternative, not just for commerce.
https://www.jpl.nasa.gov/news/the-moon-is-rusting-and-resear...
and Apollo astronauts brought back perfectly good Iron ore. It's true that there is lot of aluminum and titanium on the moon and a lunar economy might use that but there is enough iron that if loonies wanted to make things out of iron they could make things out of iron.
Making steel, with controlled carbon content, would be quite another challenge. Carbon is readily available on Mars, but only in the form of CO2.
There are numerous ways to fix carbon from CO2. If you can grow plants you can make a char out of them which what people used to use to reduce iron and add carbon as an alloying elements. There is a huge amount of research on turning CO2 into CO so that it can be mixed with H2 (then they call it syngas) and then build up larger molecules such as methane, methanol, gasoline, fats, etc.
https://news.mit.edu/2024/engineers-find-new-way-convert-car...
It's not a question of being able to do it but instead doing it better, cheaper, harder, faster, ...
The funny thing about reduction of iron (and many metals) is that it can be done with either of the two ingredients of syngas, CO [2] or H2 and either way you get the oxide CO2 or H2O as a byproduct. If space colonists think that volatiles are precious they'll practice chemical cycling, turning those back into reactive CO or H. On the moon or asteroids I'm pretty sure people would think either C or H2 is precious and wouldn't waste it, I am not sure about Martians (e.g. if you can get CO2 out of the atmosphere it might not seem like a crime to vent it)
[1] people think "technology" and they think "metals" but actually a lot of what you want is made of carbon, hydrogen, oxygen and nitrogen (CHON)
[2] what a blast furnace uses
You've got the problem that there's nothing that could manufactured on Mars that would be worth bringing back to Earth. If a Martian colony was dependent on Earth for anything it would expect to get its resources cut off at any time, and even if you can get spare parts and stuff from Earth the turn-around time counting the synodic period and transit time will always be several years. See
https://en.wikipedia.org/wiki/The_Martian_Way
I think it could be possible with some combination of synthetic biology, fermentation, flow chemistry, 3-d printing and such. It's a good northstar for research into "advanced manufacturing" which could come in handy here on Earth.
Also there's at least a plausible mass trade off - a space borne habitat structure doesn't need to support its own weight against gravity, so you might be able to trade favorably on the launch costs (e.g. grow crops in a big inflatable dome under hydroponic conditions). Certainly it would make enforcing quarantine easier.
And note that even what we call "cast iron" - a material that reasonably could be preferred to steel for some industrial purposes - is an iron-carbon alloy that in fact has more carbon than steel[1].
[0] https://www.texasironandmetal.com/strength-of-steel-compares...
[1] https://en.m.wikipedia.org/wiki/Cast_iron
it isnt always oxygen that does this, a difference of RedOx potential allowing redistribution of electrons is all you need.
mars has a perchlorate problem thus carbon compounds are converted to carbonate via Oxidation when encountering ubiquitous perchloate mineral deposits.
its toxic to carbon based biochemical forms, and destructive to carbon materials, such as carbon fibre; carbon nanotubes; carbon steel; even a lot of keypads.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Pesky Perchlorates All Over Mars:
https://www.science.org/doi/10.1126/science.340.6129.138-b
Make metals at the top of Everest. Then we’ll talk.
This is the key advantage of going to Mars or Moon surface, as opposed to operating a space station. A space station exists in a vacuum. Surface bases have access to local materials.
Sadly, very few planned space missions have this kind of ambition. That recent proposal US had about putting a nuclear reactor on the Moon was at least a step in the right direction - if you're bringing an entire reactor, that means you're establishing a permanent base, complete with an industry that would generate the demand for power.
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