4 ms·

Depends on what you want it for. For use on earth probably but there's also a lot of unexplored potential surface and near surface resources on the moon where

by rtkwe 8y ago

Depends on what you want it for. For use on earth probably but there's also a lot of unexplored potential surface and near surface resources on the moon where going deeper and deeper into the earth is quite expensive and dangerous in it's own right. For use in space especially consumables like water it makes a lot of sense to find them in space as much as possible because the rocket equation is a royal pain in the ass from the ground. Starting in space drastically increases the amount of mass we could move around. Eventually we could build the bulk of the structure in space and only lift up hard to manufacture stuff like life support and computer systems to install in space (and eventually, hopefully, be able to build everything off earth but there's a LOT of industrial base to build up before things like ICs can be manufactured off world).

all2 8y ago
For silicon based things, the moon would make sense for manufacturers. Is there enough solar energy for something like that? Specifically for smelting and refinement? What materials would need to be shipped in for manufacture?
- stcredzero 8y ago
  In a place with lab quality vacuum instead of an atmosphere, at that distance from the sun, I suspect you could use direct focused sunlight for smelting. Not sure if that would be more practical than electric furnaces, though. It would be more efficient, but the setup is less flexible.
  - hutzlibu 8y ago
    You can also do solar sintering here on earth: https://kayserworks.com/#/798817030644/ https://kayserworks.com/#/798817030644/
  - rtkwe 8y ago
    The surface of the moon itself has a tiny bit of atmosphere so I'm not sure you could do it there. https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.htm...
    - stcredzero 8y ago
      My understanding is that the Moon's atmosphere is so tiny, it's a lab quality vacuum. I got this from reading stuff from hard SF author Ben Bova. This might be a bit outdated, however. https://books.google.com/books?id=M6Fkx1hxfw8C&pg=PA190&lpg=PA190&dq=Ben+Bova++moon+vacuum&source=bl&ots=3GOCjbMLjz&sig=ACfU3U3vsS3y_WwAsljeNr0NAQ_roc6hZQ&hl=en&sa=X&ved=2ahUKEwjKndS58frhAhU8GTQIHbVWBUsQ6AEwCHoECAkQAQ#v=onepage&q=Ben%20Bova%20%20moon%20vacuum&f=false https://books.google.com/books?id=M6Fkx1hxfw8C&pg=PA190&lpg=...
      - eesmith 8y ago
        http://www.islandone.org/Settlements/DegradeLunarVacuum.html http://www.islandone.org/Settlements/DegradeLunarVacuum.html from 1990 suggests that a human presence on the Moon could make the vacuum level worse than can be achieved artificially on Earth: > Establishment of a lunar base will degrade the lunar vacuum. The time scale for distribution of exhaust gas across the surface of the moon is much less than the excape lifetime of the gas in the lunar atmosphere, and thus exhaust gas can be approximated as uniformly spread across the surface. A 20 person exploration base will contribute an amount of waste gas on the same order of magnitude as the daytime "natural" atmosphere. A 250 person "industrial" facility would be likely to contribute considerably more due to waste gas from various production processes such as lunar oxygen production and mining of helium 3 from the lunar regolith. This could degrade the lunar ambient to levels on the order of 3 nanotorr, replacing the mostly non-reactive gasses hydrogen, helium, and neon with more reactive gasses containing carbon and oxygen. This vacuum is still good enough to perform many important vacuum processes, such as plasma-deposition of amorphous silicon for solar cells, but processes such as molecular beam epitaxy or locating a intersecting beam accelerator on the moon will require additional vacuum pumping. In any case, though, pumping to ultrahigh vacuum will be much easier on the moon than on Earth.
- rtkwe 8y ago
  It's more that it's a very sensitive process with a lot of very delicate steps that'll be hard to setup. To get it started there will be some challenges adapting the processes to the lower gravity I'm sure and if it's not being manufactured on the moon transitioning the machines to microgravity is an even larger challenge. It's also just that those are some of the lighter components so building them on earth and launching them for outfitting in space will be ok for a while. Also there's a lot of chemicals used in chip manufacturing that we probably can't get on the moon at least at first in addition to just getting the silicon pure enough and the other doping elements. I'm not sure about the energy requirements but it should be doable.
  - all2 8y ago
    Part of what I was thinking of was solar panels. It makes sense (to me) to have large stuff like that manufactured on site.
    - rtkwe 8y ago
      Yeah ultimately they should be made on site. There's a lot of materials that go into them though that may not be procurable on the moon until there's a much larger mining and refinery operation.
- Symmetry 8y ago
  For half the month the lunar surface is basically paradise for solar electricity with 1.3 kw/m2 of sunlight 24 hours a day instead of just the 1.0 kw/m2 on Earth's surface for half the day. But the other half of the month is complete darkness except star and Earth light. Unless you're at one of the poles and rig a solar panel to rotate horizontally. This is good for industrial processes you can start and stop over the course of a month but life support needs lots of batteries, about 10 times the weight of the solar panels.
  - lorenzhs 8y ago
    That's not how the moon works. There's no "dark side", only a "far side" that always faces away from the earth. It's just that a moon day lasts ~28.5 earth days.
    - eesmith 8y ago
      I believe Symmetry understands that, though the phrase '24 hours a day' should be '24 hours an Earth day' to prevent possible confusion.
      - lorenzhs 8y ago
        I believe Symmetry edited their comment to correct it, or maybe I misread. Anyway, it's correct now.
        eesmith 8y ago
        Not that it makes a difference, but I like to investigate things. Symmetry has made many comments about the Moon, and they are consistent with the comment made here, and in alignment with my understanding of the physics. For examples: https://news.ycombinator.com/item?id=8959884 https://news.ycombinator.com/item?id=8959884 says "the only viable colonization sites on the moon are the north and south poles, where you can get solar power continuously." and https://news.ycombinator.com/item?id=14997459#15002984 https://news.ycombinator.com/item?id=14997459#15002984 "The Moon rotates once every month and Mars once every 24 hours. If you're using solar panels it's a big deal making it though the lunar night, you'll need lots of batteries, maybe 25 times the weight of your panels. ... There are the Peaks of Eternal Light on the south pole of the moon where this isn't an issue and you can just keep pointing your solar panels at different parts of the horizon all month." These were made 4 and 2 years ago, respectively.
bluGill 8y ago
ICs are generally small and light - they would be among the last things to make in space. I expect we would start with metals: steel is very important for building, and you need a lot of it, so making that in space gets the rocket equation strongly on your side. Rocket fuel is another one because you can cheat the rocket equation if you don't have to bring all your fuel with you. As manufacturing and space cities progress more and more industry will be brought local. I expect the main reason to target ICs is so you can deal with loss of earth type disasters. This depends of course, if zero-g is an advantage for making ICs production will move quickly. If space needs a lot of things that ICs are a byproduct of they might do it, for example a lot of solar panels would be needed in space, if there is an easy change to make ICs on the same lines of course they do it. Of course my knowledge of IC manufacturing limited, my guess is the above doesn't apply but I wouldn't be surprised if I'm wrong.
- mjevans 8y ago
  Von-numan machine style exploration is the major reason to fab anything in space. It doesn't even need to be the latest process or anything super special; it just needs to be reliable and operate within the power budget. Imagine if we surveyed the asteroid belt and sent robots to likely areas to mine for resources. Then returned them on kinetic delivery trajectories that were designed to accelerate the moon's orbital velocity (tidal effects or something else are probably slowing it down slowly over time? I forget the details) and keep it balanced. We'd probably want water, metals, and anything useful for chemical reactions sustaining life, industrial production, or high-density single use fuel. Hydrogen and Oxygen could be obtained from ice via electrolysis, which solar power could provide during the day.

by rtkwe 8y ago

all2 8y ago

For silicon based things, the moon would make sense for manufacturers. Is there enough solar energy for something like that? Specifically for smelting and refinement? What materials would need to be shipped in for manufacture?

stcredzero 8y ago
In a place with lab quality vacuum instead of an atmosphere, at that distance from the sun, I suspect you could use direct focused sunlight for smelting. Not sure if that would be more practical than electric furnaces, though. It would be more efficient, but the setup is less flexible.
- hutzlibu 8y ago
  You can also do solar sintering here on earth: https://kayserworks.com/#/798817030644/ https://kayserworks.com/#/798817030644/
- rtkwe 8y ago
  The surface of the moon itself has a tiny bit of atmosphere so I'm not sure you could do it there. https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.htm...
  - stcredzero 8y ago
    My understanding is that the Moon's atmosphere is so tiny, it's a lab quality vacuum. I got this from reading stuff from hard SF author Ben Bova. This might be a bit outdated, however. https://books.google.com/books?id=M6Fkx1hxfw8C&pg=PA190&lpg=PA190&dq=Ben+Bova++moon+vacuum&source=bl&ots=3GOCjbMLjz&sig=ACfU3U3vsS3y_WwAsljeNr0NAQ_roc6hZQ&hl=en&sa=X&ved=2ahUKEwjKndS58frhAhU8GTQIHbVWBUsQ6AEwCHoECAkQAQ#v=onepage&q=Ben%20Bova%20%20moon%20vacuum&f=false https://books.google.com/books?id=M6Fkx1hxfw8C&pg=PA190&lpg=...
    - eesmith 8y ago
      http://www.islandone.org/Settlements/DegradeLunarVacuum.html http://www.islandone.org/Settlements/DegradeLunarVacuum.html from 1990 suggests that a human presence on the Moon could make the vacuum level worse than can be achieved artificially on Earth: > Establishment of a lunar base will degrade the lunar vacuum. The time scale for distribution of exhaust gas across the surface of the moon is much less than the excape lifetime of the gas in the lunar atmosphere, and thus exhaust gas can be approximated as uniformly spread across the surface. A 20 person exploration base will contribute an amount of waste gas on the same order of magnitude as the daytime "natural" atmosphere. A 250 person "industrial" facility would be likely to contribute considerably more due to waste gas from various production processes such as lunar oxygen production and mining of helium 3 from the lunar regolith. This could degrade the lunar ambient to levels on the order of 3 nanotorr, replacing the mostly non-reactive gasses hydrogen, helium, and neon with more reactive gasses containing carbon and oxygen. This vacuum is still good enough to perform many important vacuum processes, such as plasma-deposition of amorphous silicon for solar cells, but processes such as molecular beam epitaxy or locating a intersecting beam accelerator on the moon will require additional vacuum pumping. In any case, though, pumping to ultrahigh vacuum will be much easier on the moon than on Earth.
rtkwe 8y ago
It's more that it's a very sensitive process with a lot of very delicate steps that'll be hard to setup. To get it started there will be some challenges adapting the processes to the lower gravity I'm sure and if it's not being manufactured on the moon transitioning the machines to microgravity is an even larger challenge. It's also just that those are some of the lighter components so building them on earth and launching them for outfitting in space will be ok for a while. Also there's a lot of chemicals used in chip manufacturing that we probably can't get on the moon at least at first in addition to just getting the silicon pure enough and the other doping elements. I'm not sure about the energy requirements but it should be doable.
- all2 8y ago
  Part of what I was thinking of was solar panels. It makes sense (to me) to have large stuff like that manufactured on site.
  - rtkwe 8y ago
    Yeah ultimately they should be made on site. There's a lot of materials that go into them though that may not be procurable on the moon until there's a much larger mining and refinery operation.
Symmetry 8y ago
For half the month the lunar surface is basically paradise for solar electricity with 1.3 kw/m2 of sunlight 24 hours a day instead of just the 1.0 kw/m2 on Earth's surface for half the day. But the other half of the month is complete darkness except star and Earth light. Unless you're at one of the poles and rig a solar panel to rotate horizontally. This is good for industrial processes you can start and stop over the course of a month but life support needs lots of batteries, about 10 times the weight of the solar panels.
- lorenzhs 8y ago
  That's not how the moon works. There's no "dark side", only a "far side" that always faces away from the earth. It's just that a moon day lasts ~28.5 earth days.
  - eesmith 8y ago
    I believe Symmetry understands that, though the phrase '24 hours a day' should be '24 hours an Earth day' to prevent possible confusion.
    - lorenzhs 8y ago
      I believe Symmetry edited their comment to correct it, or maybe I misread. Anyway, it's correct now.
      - eesmith 8y ago
        Not that it makes a difference, but I like to investigate things. Symmetry has made many comments about the Moon, and they are consistent with the comment made here, and in alignment with my understanding of the physics. For examples: https://news.ycombinator.com/item?id=8959884 https://news.ycombinator.com/item?id=8959884 says "the only viable colonization sites on the moon are the north and south poles, where you can get solar power continuously." and https://news.ycombinator.com/item?id=14997459#15002984 https://news.ycombinator.com/item?id=14997459#15002984 "The Moon rotates once every month and Mars once every 24 hours. If you're using solar panels it's a big deal making it though the lunar night, you'll need lots of batteries, maybe 25 times the weight of your panels. ... There are the Peaks of Eternal Light on the south pole of the moon where this isn't an issue and you can just keep pointing your solar panels at different parts of the horizon all month." These were made 4 and 2 years ago, respectively.

bluGill 8y ago

ICs are generally small and light - they would be among the last things to make in space. I expect we would start with metals: steel is very important for building, and you need a lot of it, so making that in space gets the rocket equation strongly on your side. Rocket fuel is another one because you can cheat the rocket equation if you don't have to bring all your fuel with you. As manufacturing and space cities progress more and more industry will be brought local. I expect the main reason to target ICs is so you can deal with loss of earth type disasters. This depends of course, if zero-g is an advantage for making ICs production will move quickly. If space needs a lot of things that ICs are a byproduct of they might do it, for example a lot of solar panels would be needed in space, if there is an easy change to make ICs on the same lines of course they do it. Of course my knowledge of IC manufacturing limited, my guess is the above doesn't apply but I wouldn't be surprised if I'm wrong.

mjevans 8y ago
Von-numan machine style exploration is the major reason to fab anything in space. It doesn't even need to be the latest process or anything super special; it just needs to be reliable and operate within the power budget. Imagine if we surveyed the asteroid belt and sent robots to likely areas to mine for resources. Then returned them on kinetic delivery trajectories that were designed to accelerate the moon's orbital velocity (tidal effects or something else are probably slowing it down slowly over time? I forget the details) and keep it balanced. We'd probably want water, metals, and anything useful for chemical reactions sustaining life, industrial production, or high-density single use fuel. Hydrogen and Oxygen could be obtained from ice via electrolysis, which solar power could provide during the day.