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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 c

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.

deleted 1y ago
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thaumasiotes 1y 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 1y 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 1y ago
    The idea you see in O'Neill and other science fiction that iron is rare on the moon is bunk. There is Hematite https://www.jpl.nasa.gov/news/the-moon-is-rusting-and-researchers-want-to-know-why/ 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.
    - jacquesm 1y ago
      Yes, absolutely, but they specifically asked about aluminum. Mining iron or aluminum on the moon would be trivial compared to earth in terms of access. Getting the gear there to bootstrap it all would be an interesting technical problem but I think it is solvable. Why you would want to do it to me is only to jump start a deep space program taking advantage of the reduced requirements to reach escape velocity while still having a long term platform to build on. If you want to do better than that then space construction will have to go to a completely different level first.
      - PaulHoule 1y ago
        ISRU tends to make no sense at all when you have to move things from place to place, it makes more sense when you use them in place. For instance there may be some usable ice at the moon's poles maybe even some carbon. You could get oxygen out of rocks one way or another. You could make rocket fuel and launch stuff the conventional way but there are two problems: (1) Earth is the most competitive and cheapest market for everything in the solar system, and (2) lunar colonists might see volatiles as precious and decide to circularize them rather than expend them. [1] [2] Contrast that to Earth which has plenty of volatiles. There is the idea of O'Neill and Heinlein [1] of the lunar mass driver, the picture you get from The High Frontier and The Moon is a Harsh Mistress that it looks like a maglev train a few km long is totally wrong because your elevation angle is pretty high if you want to target the Earth-Moon L1 point or the Earth or LEO (assuming you can aerobrake reliably) If it is a few km long it is a slanted hole a few km deep. I don't know about coilguns but a railgun with 2.5 km/s that would fit on a ship has been tested [3] and you need 3.5 km/s to get to L1 -- one way or another I think a viable mass driver looks like the Paris Gun and shoots small payloads. If you could launch a 1kg payload per second you could put up a rail car worth of material in a day. O'Neill's students thought a lot about the "catcher" for stuff from the lunar mass driver and never came up with anything convincing if anybody else has I haven't seen it. [1] See The Moon is a Harsh Mistress [2] Niven's Protector talks about the problem of very long-term space colonies , starships and stuff losing volatiles at steady rate no matter how well you try to keep them in. [3] ... and burns up the barrels
lstodd 1y ago
delta-V happened to asteroid folks. there are no realistic proposals for asteroid drives ala https://en.wikipedia.org/wiki/K240 https://en.wikipedia.org/wiki/K240
- PaulHoule 1y ago
  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 1y 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.
jacquesm 1y 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.
pstuart 1y ago
24/7 solar furnaces harvesting asteroids seems like a huge industry once it's figured out. The big problem is that it would take a billionaire to make it happen.

deleted 1y ago

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thaumasiotes 1y 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 1y 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 1y ago
  The idea you see in O'Neill and other science fiction that iron is rare on the moon is bunk. There is Hematite https://www.jpl.nasa.gov/news/the-moon-is-rusting-and-researchers-want-to-know-why/ 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.
  - jacquesm 1y ago
    Yes, absolutely, but they specifically asked about aluminum. Mining iron or aluminum on the moon would be trivial compared to earth in terms of access. Getting the gear there to bootstrap it all would be an interesting technical problem but I think it is solvable. Why you would want to do it to me is only to jump start a deep space program taking advantage of the reduced requirements to reach escape velocity while still having a long term platform to build on. If you want to do better than that then space construction will have to go to a completely different level first.
    - PaulHoule 1y ago
      ISRU tends to make no sense at all when you have to move things from place to place, it makes more sense when you use them in place. For instance there may be some usable ice at the moon's poles maybe even some carbon. You could get oxygen out of rocks one way or another. You could make rocket fuel and launch stuff the conventional way but there are two problems: (1) Earth is the most competitive and cheapest market for everything in the solar system, and (2) lunar colonists might see volatiles as precious and decide to circularize them rather than expend them. [1] [2] Contrast that to Earth which has plenty of volatiles. There is the idea of O'Neill and Heinlein [1] of the lunar mass driver, the picture you get from The High Frontier and The Moon is a Harsh Mistress that it looks like a maglev train a few km long is totally wrong because your elevation angle is pretty high if you want to target the Earth-Moon L1 point or the Earth or LEO (assuming you can aerobrake reliably) If it is a few km long it is a slanted hole a few km deep. I don't know about coilguns but a railgun with 2.5 km/s that would fit on a ship has been tested [3] and you need 3.5 km/s to get to L1 -- one way or another I think a viable mass driver looks like the Paris Gun and shoots small payloads. If you could launch a 1kg payload per second you could put up a rail car worth of material in a day. O'Neill's students thought a lot about the "catcher" for stuff from the lunar mass driver and never came up with anything convincing if anybody else has I haven't seen it. [1] See The Moon is a Harsh Mistress [2] Niven's Protector talks about the problem of very long-term space colonies , starships and stuff losing volatiles at steady rate no matter how well you try to keep them in. [3] ... and burns up the barrels

lstodd 1y ago

delta-V happened to asteroid folks. there are no realistic proposals for asteroid drives ala https://en.wikipedia.org/wiki/K240 https://en.wikipedia.org/wiki/K240

PaulHoule 1y ago
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 1y 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.

jacquesm 1y 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.

pstuart 1y ago

24/7 solar furnaces harvesting asteroids seems like a huge industry once it's figured out. The big problem is that it would take a billionaire to make it happen.