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You're talking about two very different scenarios. Metals would be brought back to Earth to improve life here. Carbon, Hydrogen, Oxygen and Nitrogen would be e

You're talking about two very different scenarios. Metals would be brought back to Earth to improve life here. Carbon, Hydrogen, Oxygen and Nitrogen would be essential to establishing habitats in space but close to useless if brought back to Earth.

ianai 3y ago
I could see more water being useful in earth. Probably a way to fend off climate change in there too.
- leereeves 3y ago
  You might be right. Earth has plenty of water but not enough in some places. Perhaps an icy asteroid could help, if it was parked in orbit and slowly dropped rain on the deserts. But then the sea levels would rise, and the water vapor would act as a greenhouse gas.
  - PaulHoule 3y ago
    Ocean levels are going up anyway and that is a problem. It doesn’t seem that climate change is worsening hurricanes directly in Florida. But you better believe a lot of Miami is low lying and storm surges will get wors.pe. My understanding is that almost all the water in small bodies inside Jupiter’s orbit is in Ceres and the amount of water on Ceres is similar to what is on the Earth’s oceans. I think it is better to send people there and grow a population organically as you could reassemble Ceres into more living space than Mars and get people ready for colonization of generic outer solar system and interstellar objects.
    - ianai 3y ago
      We talk about the ppm of co2 in effect on climate. I was even thinking of releasing additional o2 in that above comment. Or similar -“dissolve“ the carbon in additional atmosphere. But no ideas on secondary effects.
  - eesmith 3y ago
    https://what-if.xkcd.com/ https://what-if.xkcd.com/ >> Could I cool down the Earth by capturing a comet and dropping it in the ocean, like an ice cube in a glass of water? > No. In fact, it's honestly sort of impressive to find a solution that would actively make the problem worse in so many different ways. The short answer is, the falling ice adds about 100x as much heat from the difference in potential energy than it cools.
PaulHoule 3y ago
Exactly. The main problem with any space mining or processing is the extreme cost of transporting materials to a destination. If you extract materials on Luna you use them in Luna, extract them on Mars you use them in Mars, etc. Earth will be the cheapest source of most things in cislunar space for a long time. By the time we can get platinum group metals on Earth people will have advanced a lot in developing iron-based, synthetic enzyme and other chemistry that makes platinum group metals obsolete.
- JumpCrisscross 3y ago
  > If you extract materials on Luna you use them in Luna, extract them on Mars you use them in Mars, etc. The Moon and Mars are relatively deep gravity wells. The economics of extraction in a deep well are totally different from those on light platforms. For an asteroid, over the long run, transport costs are minimal. (You can move mass very slowly and thus efficiently when you have that much of it.)
  - PaulHoule 3y ago
    I have some notes on the problem of making a factory that builds a solar sail factory on a carbonaceous asteroid and then the sails fly back on their own power to the Earth-Sun L1 point and get commissioned as sunshades to fight global warming. I gotta turn it into a serious write-up or presentation. I think this solves the transport problem for space manufacturing. I know the math can sorta work if you use volatiles for transportation (e.g. rocket) but it seems so wasteful to me. Two problems that bug me are: (1) How do you capture volatiles that will be released when you disturb the surface? (Have to do this early before you have a storage tank factory running) and (2] How do you debug problems in the system with 10 min+ latency. Is it good enough to have a manned replica factory in cislunar space? Do you send people? If so do you just go “all in” in building a large habitat in the long term?
  - venusenvy47 3y ago
    Wouldn't Earth's even bigger gravity well be a problem for getting asteroid metal to the surface of Earth? I think you would need a tremendous amount of rocket fuel to bring back large quantities of asteroid gold. I don't think you can just "drop" all that metal onto Earth for free.
BashiBazouk 3y ago
Most of the asteroid is iron with some nickle even though most the articles talk up the gold and platinum. I would think steel would also be great in establishing habitats in space and it would be nice to have a source without the launch costs of getting it out of earth orbit.
- adrian_b 3y ago
  While the average content of gold and platinum-group elements in an iron asteroid is many thousands of times higher than their average content in the crust of the Earth, that does not mean that these metals are easy to mine. Unlike on Earth, where various processes have concentrated the precious metal into some deposits where they are much more abundant than on average, e.g. in alluvial deposits in river beds or in magmatic sulfide deposits, on such an asteroid the precious metals are dissolved in iron and spread uniformly through all the asteroid. Therefore even if the total amount of precious metals is very great, a huge quantity of energy is required for its extraction. For instance, in order to produce one kilogram of gold more than four hundred tons of iron will have to be processed (e.g. by first producing hundreds of tons of some acid used to dissolve the iron and the other non-precious metals). So it is very unlikely that we will see any such mining operation soon. There are other metals much easier to mine in such a place, e.g. iron, nickel, cobalt, germanium, chromium, gallium, manganese (but which are not worthwhile to be brought back to Earth).
  - venusenvy47 3y ago
    Aside from the mining difficulties, I think the transportation costs of bringing large quantities of metal back to Earth would be expensive. Even if there were pallets of gold bars stacked neatly on the surface of the asteroid, it would be expensive to bring large payloads back on spaceships.

ianai 3y ago

I could see more water being useful in earth. Probably a way to fend off climate change in there too.

leereeves 3y ago
You might be right. Earth has plenty of water but not enough in some places. Perhaps an icy asteroid could help, if it was parked in orbit and slowly dropped rain on the deserts. But then the sea levels would rise, and the water vapor would act as a greenhouse gas.
- PaulHoule 3y ago
  Ocean levels are going up anyway and that is a problem. It doesn’t seem that climate change is worsening hurricanes directly in Florida. But you better believe a lot of Miami is low lying and storm surges will get wors.pe. My understanding is that almost all the water in small bodies inside Jupiter’s orbit is in Ceres and the amount of water on Ceres is similar to what is on the Earth’s oceans. I think it is better to send people there and grow a population organically as you could reassemble Ceres into more living space than Mars and get people ready for colonization of generic outer solar system and interstellar objects.
  - ianai 3y ago
    We talk about the ppm of co2 in effect on climate. I was even thinking of releasing additional o2 in that above comment. Or similar -“dissolve“ the carbon in additional atmosphere. But no ideas on secondary effects.
- eesmith 3y ago
  https://what-if.xkcd.com/ https://what-if.xkcd.com/ >> Could I cool down the Earth by capturing a comet and dropping it in the ocean, like an ice cube in a glass of water? > No. In fact, it's honestly sort of impressive to find a solution that would actively make the problem worse in so many different ways. The short answer is, the falling ice adds about 100x as much heat from the difference in potential energy than it cools.

PaulHoule 3y ago

Exactly. The main problem with any space mining or processing is the extreme cost of transporting materials to a destination. If you extract materials on Luna you use them in Luna, extract them on Mars you use them in Mars, etc. Earth will be the cheapest source of most things in cislunar space for a long time. By the time we can get platinum group metals on Earth people will have advanced a lot in developing iron-based, synthetic enzyme and other chemistry that makes platinum group metals obsolete.

JumpCrisscross 3y ago
> If you extract materials on Luna you use them in Luna, extract them on Mars you use them in Mars, etc. The Moon and Mars are relatively deep gravity wells. The economics of extraction in a deep well are totally different from those on light platforms. For an asteroid, over the long run, transport costs are minimal. (You can move mass very slowly and thus efficiently when you have that much of it.)
- PaulHoule 3y ago
  I have some notes on the problem of making a factory that builds a solar sail factory on a carbonaceous asteroid and then the sails fly back on their own power to the Earth-Sun L1 point and get commissioned as sunshades to fight global warming. I gotta turn it into a serious write-up or presentation. I think this solves the transport problem for space manufacturing. I know the math can sorta work if you use volatiles for transportation (e.g. rocket) but it seems so wasteful to me. Two problems that bug me are: (1) How do you capture volatiles that will be released when you disturb the surface? (Have to do this early before you have a storage tank factory running) and (2] How do you debug problems in the system with 10 min+ latency. Is it good enough to have a manned replica factory in cislunar space? Do you send people? If so do you just go “all in” in building a large habitat in the long term?
- venusenvy47 3y ago
  Wouldn't Earth's even bigger gravity well be a problem for getting asteroid metal to the surface of Earth? I think you would need a tremendous amount of rocket fuel to bring back large quantities of asteroid gold. I don't think you can just "drop" all that metal onto Earth for free.

BashiBazouk 3y ago

Most of the asteroid is iron with some nickle even though most the articles talk up the gold and platinum. I would think steel would also be great in establishing habitats in space and it would be nice to have a source without the launch costs of getting it out of earth orbit.

adrian_b 3y ago
While the average content of gold and platinum-group elements in an iron asteroid is many thousands of times higher than their average content in the crust of the Earth, that does not mean that these metals are easy to mine. Unlike on Earth, where various processes have concentrated the precious metal into some deposits where they are much more abundant than on average, e.g. in alluvial deposits in river beds or in magmatic sulfide deposits, on such an asteroid the precious metals are dissolved in iron and spread uniformly through all the asteroid. Therefore even if the total amount of precious metals is very great, a huge quantity of energy is required for its extraction. For instance, in order to produce one kilogram of gold more than four hundred tons of iron will have to be processed (e.g. by first producing hundreds of tons of some acid used to dissolve the iron and the other non-precious metals). So it is very unlikely that we will see any such mining operation soon. There are other metals much easier to mine in such a place, e.g. iron, nickel, cobalt, germanium, chromium, gallium, manganese (but which are not worthwhile to be brought back to Earth).
- venusenvy47 3y ago
  Aside from the mining difficulties, I think the transportation costs of bringing large quantities of metal back to Earth would be expensive. Even if there were pallets of gold bars stacked neatly on the surface of the asteroid, it would be expensive to bring large payloads back on spaceships.