szabo@sequent.com (06/16/91)
In article <1991Jun16.000359.10311@world.std.com> webber@world.std.com (Robert D Webber) writes: [Excellent article re: asteroid mining] >In the absence of a container the composition of the GaAs crystal comes >out wrong... This is an interesting statement; why does this occur? >>First, we should find grains with the above concentrations or better >>in a high-metal regolith (a task for space exploration). We >>extract the metal grains with a magnetic rake. Next, we process >>the metal regolith with the gaseous carbonyl process, as follows: > >You will need to break the hunk of rock down in size quite a bit, first... I agree that breaking down the solid metal is difficult. I don't propose to do that for the first mining projects. I am looking for metal regolith (dust and flakes) that is ready to melt. This is known to exist in very small percentages scattered on the Lunar surface, and probably exists in much higher concentrations, perhaps up to >90%, on the surface of metallic asteroids. Alternatively, brittle chondrites contain up to 30% metal flakes and this can be crushed and raked with a magnet to get nearly pure metal regolith. Exploration can make the mining operations much simpler by pointing out the most easily processed material. >So how much does it cost to get the carbon monoxide and water up there >in the first place? Good question. The answer is that comets, carbonaceous chondrite asteroids, and possibly comet fragments in meteor showers contain carbon compounds including carbon monoxide, and also contain abundant water. The ice can be captured using solar thermal engines and the ice itself as reaction mass. The ice-mining operation will have to pay for itself in terms of reaction mass, shielding, heat sinks, and fuel manufactured from the ice materials and used in Earth orbit. I call this "ice bootstrapping" since ice as reaction mass can be used to lift more equipment to catch more chunks of ice, etc. until the cost of fuel, heat sinks, and shielding in Earth orbit is very low. As you point out rock and metal processing is quite non-trivial. In comparison, however, ice mining requires little more than a mirror, bag, and simple distillery. After the ice bootstrapping takes place, it will be much easier to lift heavy mining equipment out to the asteroids, or alternatively bring raw asteroid regolith to Earth orbit and process it there. The ice also provides the water and carbon monoxide needed for the carbonyl process. Volatile mining will likely be the first use of extraterrestrial materials, but it cannot occur until we have explored the earth-crossing asteroids and meteor showers sufficiently to find good sources of ice, or, failing that, the highest concentrations of water of hydration and carbon in chondrites. >Incidentally, you will need a fair bit of material for the >carbonyl process fixtures as well. The units I saw on a tour of the >Inco facilities in Sudbury were pretty massive, though I'll grant you >that a space facility can be less concerned about accidental carbonyl >releases than an earth-based one. This is a rather underated aspect of space industry. In the long run, it can replace many Earthside industries that really should not be conducted in the middle of an ecosystem. In the short run, the ability to work outside the ecosystem can make some processes significantly cheaper. I am not sure to what extent the carbonyl process is an example; can any readers shed more light on this? >>If we want to get the pure elements additional processing is >>required. > >No kidding?! :-) At this point the impure mixture of platinum-group elements, gallium, arsenic, and other stuff is already worth $20,000/kg. The rest of the processing can be done on Earth. If we want to use any of these in the pure form in orbit, we need the "additional processing." >I've often wondered whether any of the people who figure that metallurgical >operations in space would be simple have ever visited an earthside >metals extraction plant. I share your impatience. In the space community there is an underestimation of mining engineering across the spectrum of mining operations. Many "Manned Mars Mission" scenarios, for example, propose extracting fuel from extraterrestrial regolith and assume that the mining engineering is going to be trivial without detailed analysis or, for that matter, even bothering to ask a mining engineer. Mining equipment is itself difficult; mining equipment in vacuum and microgravity will take much engineering and trial and error before we get it right. On the other hand, if we use the abundant thermal energy, microgravity, and vacuum to full advantage, some of the processes become much easier. (Some become much harder, so we don't use those). That is my other pet peeve on this subject. Merely transfering Earth mining techniques into space is stupidity. We need to take full advantage of the new environment. Much work has to be done to determine which processes gain the most advantage, what new processes are made possible, and how much can be done with the least mass of equipment. The actual mines will bear very little outward resemblence to their Earthside counterparts. At $3.4 billion/year for just the platinum-group elements, billions more for space-manufactured semiconductors, alloys, and other products, and potentially tens of billions per year for solar power satellites, there is quite a bit of incentive for that work to get done. -- Nick Szabo szabo@sequent.com Embrace Change... Keep the Values... Hold Dear the Laughter... These views are my own, and do not represent any organization.
rockwell@socrates.umd.edu (Raul Rockwell) (06/17/91)
Nick Szabo: ... rock and metal processing is quite non-trivial. In comparison, however, ice mining requires little more than a mirror, bag, and simple distillery. After the ice bootstrapping takes place, it will be much easier to lift heavy mining equipment out to the asteroids, or alternatively bring raw asteroid regolith to Earth orbit and process it there. Why process in Earth orbit? Seems to me that you could do quite a lot, in terms of smelting, or whatever, by processing during the transfer orbit. Sure, it would take a few years, but so what? -- Raul <rockwell@socrates.umd.edu>
sking@nowhere.uucp (Steven King) (06/17/91)
Of course, all of this presumes that even if you were to get
there and the processes were viable, that the asteriod is yours
to mine. International law, as I understand it, is less than clear
on this issue. A few billion in precious metals might buy a lot
of influence, but it would also buy a lot of envy.
--
If it don't stick, stink, or sting
It ain't from Texas.
..!cs.utexas.edu!ut-emx!nowhere!skingszabo@sequent.com (06/17/91)
In article <ROCKWELL.91Jun16134443@socrates.umd.edu> rockwell@socrates.umd.edu (Raul Rockwell) writes: >Why process in Earth orbit? Seems to me that you could do quite a >lot, in terms of smelting, or whatever, by processing during the >transfer orbit. Sure, it would take a few years, but so what? Two problems: lifting the heavy processing equipment out to the asteroid, and the round-trip light time for teleoperation. On the other hand, capturing volatiles and raw regolith into Earth orbit will take fairly little equipment and energy, if Earth gravity assist and/or slow aerobraking are used. See previous postings in sci.space for the safety issues involved (a crude summary is that gravity assist and slow aerobraking of small amounts of regolith and ice are fine; fast aerobraking and large solid pieces can be dangerous). Once we have the volatiles and asteroid materials in Earth orbit, equipment can be built and launched from Earth to process the materials into the final products (fuel, heat sinks, shielding, Pt-group metals, new alloys, semiconductors, solar power satellites, etc.). -- Nick Szabo szabo@sequent.com Embrace Change... Keep the Values... Hold Dear the Laughter... These views are my own, and do not represent any organization.
aws@iti.org (Allen W. Sherzer) (06/17/91)
In article <1991Jun17.021943.6721@sequent.com> szabo@sequent.com writes: >>Why process in Earth orbit? Seems to me that you could do quite a >>lot, in terms of smelting, or whatever, by processing during the >>transfer orbit. Sure, it would take a few years, but so what? >Two problems: lifting the heavy processing equipment out to the >asteroid, That shouldn't be a problem. After all, most of the energy and cost is spent getting to LEO. After you get to LEO you are half way to anywhere. >and the round-trip light time for teleoperation. So we send people. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer | DETROIT: Where the weak are killed and eaten. | | aws@iti.org | | +---------------------------------------------------------------------------+
wreck@fmsrl7.UUCP (Ron Carter) (06/19/91)
In <1991Jun16.234110.7241@nowhere.uucp> sking@nowhere.uucp (Steven King) writes: > Of course, all of this presumes that even if you were to get > there and the processes were viable, that the asteriod is yours > to mine. International law, as I understand it, is less than clear > on this issue. A few billion in precious metals might buy a lot > of influence, but it would also buy a lot of envy. Q: How do spacers pay their taxes? A: In gold and platinum, at terminal velocity. The nice thing about moving ton-sized payloads around space is that you can always arrange to drop one, or a few. (Use slag or iron, that way nobody is going to WANT to be the recipient.) If someone gets too envious, you can at least make them keep their head down. I'd suggest paying taxes to the USA or EEC, which are not going to want to jeapordize their revenue stream and will defend it against other entities.