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gbaikie
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« Reply #30 on: 05/01/2012 02:30 AM » |
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The orbital refinery is somewhat necessary for lunar mining. But lunar mining isn't necessary for the orbital refinery. The answer, therefore, is asteroids.
<snip>
From a lunar miners point of view, all that is essential is a depot in L-1 with fuel on Moon being made on the Moon.
Absolutely. But why bother?
Once the depot exists at EML1/2, one then brings power, personnel, refining equipment to EML1/2, and then...drops it down into the gravity well? And then builds a refinery in a gravity well? Why not keep it where it is, in EML1/2?
If you have rocket fuel at L-1, you will have people going to the Moon. Some people [actual huge majority] will not bother. Or NASA might not bother, if wants to focus on exploring Mars. I believe, NASA should limit itself to exploring the Moon to find minable water, then NASA should focus on Manned Mars. If NASA focuses on Manned Mars, others will mine the Moon, and do other things on the Moon, tourism, further exploration, etc. And before NASA "finishes" exploring Mars- a decadal project, they will have settlers coming to Mars. Which is why NASA should explore Mars. The Moon's gravity doesn't do anything for the personnel. It just makes it harder to get the refined fuel back, and frankly you're going to launch lunar material using a mass driver anyway.
One will get a mass driver on the Moon at some point. If you want mass driver at the start, it will cost on order of tens of billions of dollars. Who should spend that much money? NASA? Bill Gates? No problem with Gates putting up the capital- might make another tens of billions, though perhaps not. But once you get to the point of mining hundreds to thousands of tons of Lunar water per year, have existing market for this mass driver [which can ship thousands of tons per year] and it could at that point cost less than 10 billion dollar to construct. So, you will get a driver driver, when a mass driver makes economic sense to build one. Maybe the same goes for Space Elevators in order to leave earth, but in the meantime chemical rockets are the cheapest route. You'd be insane to use fuel. And that material is more valuable whole, not processed, when it reaches EML1/2, so you'll simply bag, launch and refine it in orbit. But now we've established that your refinery's in orbit around the Moon.
And now it's easier to get asteroid material to your refinery/fuel depot at EML1/2 than it is to build your mass driver.
Yes I would agree. I'm not saying the mass driver won't be built. But it won't be built first. And frankly, if it is built it will probably be built to supply material for a rotating station, in which case virtually no one would rather live on the Moon instead of on the station. So the Moon stays relegated to being a small research outpost.
If one is mining asteroids- commercially, not as some weird governmental hobby. One is going to get a huge amount material that needs customers. So people who want brick houses in LEO, will have a source of cheap bricks. If one mining water and making rocket fuel from Asteroids, you have to make a lot rocket fuel, which means cheap rocket fuel, which means people living on the Moon, Mars, Mercury, Venus, LEO, and L-5 type mega projects.
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daveklingler
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« Reply #31 on: 05/01/2012 04:11 AM » |
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I'm not saying the mass driver won't be built. But it won't be built first. And frankly, if it is built it will probably be built to supply material for a rotating station, in which case virtually no one would rather live on the Moon instead of on the station. So the Moon stays relegated to being a small research outpost.
If one is mining asteroids- commercially, not as some weird governmental hobby. One is going to get a huge amount material that needs customers. So people who want brick houses in LEO, will have a source of cheap bricks.
If one has material and fuel arriving on one's doorstep, one has a source of shielding and growing material for big rotating orbital habitats. Slag, i.e. dirt, is valuable in orbit!If one mining water and making rocket fuel from Asteroids, you have to make a lot rocket fuel, which means cheap rocket fuel, which means people living on the Moon, Mars, Mercury, Venus, LEO, and L-5 type mega projects.
None of the other planets have Earth-normal gravity, or temperatures, or breathable air. If you run the numbers, it's much easier and cheaper to skip the other bodies and build our own habitats, with the correct gravity, air, plants, trees and animals from Earth. Why try to populate the other gravity wells, nasty as they are? I finally understand Asimov's term, "planetary prejudice".
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QuantumG
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« Reply #32 on: 05/01/2012 04:27 AM » |
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I like your thinking. I'll just add: habitats + propulsion = spacefaring.
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douglas100
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« Reply #33 on: 05/01/2012 09:30 AM » |
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None of the other planets have Earth-normal gravity, or temperatures, or breathable air. If you run the numbers, it's much easier and cheaper to skip the other bodies and build our own habitats, with the correct gravity, air, plants, trees and animals from Earth. Why try to populate the other gravity wells, nasty as they are? I finally understand Asimov's term, "planetary prejudice".
Agree with that. No need to waste energy terraforming Mars either. And I voted for the Moon.
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JohnFornaro
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« Reply #34 on: 05/01/2012 01:05 PM » |
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... Once the depot exists at EML1/2, one then brings power, personnel, refining equipment to EML1/2, and then...drops it down into the gravity well? And then builds a refinery in a gravity well? Why not keep it where it is, in EML1/2? The Moon's gravity doesn't do anything for the personnel. ... Here we go with the gravity well again. Let's rewrite the above paragraph a mite: Once the depot exists at EML1/2, after having been launched from Earth's gravity well, one then brings power, personnel, refining equipment to EML1/2, launching all that from Earth's gravity well, and then...drops it down into the one sixth gee gravity well on Luna? And then builds a refinery in that same one sixth gee gravity well? Why not keep it where it is, in EML1/2? The Moon's gravity doesn't do anything for the personnel, except ameliorate the long term effects of zero gee. If there is any credence to the supposition that the Earth's economy would benefit from the addition of many tons of PGM's, there is the largest gravity well of the three locations mentioned, still to be dealt with. Gravity comes with the universe. Get over it. Mass is your friend; you need a lot of it. Gravity wells, like delta vee, need to be kept in perspective. Neither of these celestial mechanical qualities, by themselves, drive the further development of either cis-lunar, or cis-asteroidal (?) space. I'm certain that the correct answer to the OP is "coin toss". Who here knows? If one has material and fuel arriving on one's doorstep, one has a source of shielding and growing material for big rotating orbital habitats. Slag, i.e. dirt, is valuable in orbit! True. Mass is your friend. I have nothing against O'Neill cylinders or ring stations or other propulsive habs, in principle. However, dealing with those quantities of loose slag, without the handy effects of a large gravity well underneath them, still need to be solved, and you have not suggested any solutions to that problem. None of the other planets have Earth-normal gravity, or temperatures, or breathable air. If you run the numbers, it's much easier and cheaper to skip the other bodies and build our own habitats, with the correct gravity, air, plants, trees and animals from Earth. Why try to populate the other gravity wells, nasty as they are? I finally understand Asimov's term, "planetary prejudice". "Nasty gravity wells"? How on Earth do you manage to live here? You allude that you have "run the numbers", but it is only your assertion. There is no clear and widely accepted agreement that propulsive habs are more likely to be developed first. Interestingly enough, you acknowledge the importance of gravity in these propulsive habs. That can only be managed by rotation, which will present a large engineering challenge in its own right, as would any propulsive ability for such a large hab. Plus, the mass of the people and their stuff from home to inhabit it, must be launched from a gravity well. If not, then, you're supposing an Adam and Eve premise, which is not likely to come about. Asimov's term has no practical application. It is a coin toss.
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go4mars
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« Reply #35 on: 05/01/2012 02:01 PM » |
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dealing with those quantities of loose slag, without the handy effects of a large gravity well underneath them, still need to be solved, and you have not suggested any solutions to that problem. Probably because there are many ways to do it, some of which are dependent on the metals fractionation process decision and composition. Sintering into bricks, collecting in bags, are among options. They might even be collected by Jon Goff's stickyboom. etc. None of the other planets have Earth-normal gravity, it's much easier and cheaper to skip the other bodies ... with the correct gravity...Why try to populate the other gravity wells, nasty as they are? I finally understand Asimov's term, "planetary prejudice". If needed on Mars (still unproven), rotation habs can be built on Mars too (yes with some degree of frictional losses). In my view, even if these are necessary (if only for pregnant mothers), the benefits of having the enormous resources of a planetary atmosphere, lithosphere, and hydrosphere far outweigh an O'neil type of set-up. Though I would wish you success in building one, I would like to be able to go for a long walk or drive, do a little golfing, see the windstorms and clouds, etc.. You imply that "planetary prejudice" is a bad thing. In the absence of large, advanced propulsion ships, it seems warranted. But I'm OT again. Sorry.
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Danderman
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« Reply #36 on: 05/01/2012 02:51 PM » |
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The biggest problem for both is transport of the refined ore from the excavation site to customers. A metric ton of pure PGM probably has a value of > $60 million; unfortunately, the costs to transport the PGM and any residual rock from the original site to Earth would probably cost > $60 million.
This includes the cost of moving an asteroid to lunar orbit, or launching refined ore from the surface of the Moon.
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savuporo
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« Reply #37 on: 05/01/2012 03:04 PM » |
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unfortunately, the costs to transport the PGM and any residual rock from the original site to Earth would probably cost > $60 million.
I fail to understand this point. Surely if you have advanced enough tech to mine and refine PGMs at a space rock, you are advanced enough to get iron and aluminum out, which would enable all sorts of "for free" return strategies.
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Robotbeat
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« Reply #38 on: 05/01/2012 03:08 PM » |
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The biggest problem for both is transport of the refined ore from the excavation site to customers. A metric ton of pure PGM probably has a value of > $60 million; unfortunately, the costs to transport the PGM and any residual rock from the original site to Earth would probably cost > $60 million.
This includes the cost of moving an asteroid to lunar orbit, or launching refined ore from the surface of the Moon.
A metric ton of pure PGM would probably survive reentry and would reach terminal velocity. Really, if you can get a metric ton of pure PGM, you've already won the war. I disagree with your premise. The other parts are going to be harder. Transportation costs are just easier to quantify (which is why we focus so much on them).
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Danderman
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« Reply #39 on: 05/01/2012 03:14 PM » |
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Really, if you can get a metric ton of pure PGM, you've already won the war. I disagree with your premise. The other parts are going to be harder. Transportation costs are just easier to quantify (which is why we focus so much on them).
Please advise how to move ore cheaply.
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savuporo
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« Reply #40 on: 05/01/2012 03:24 PM » |
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Please advise how to move ore cheaply.
Mass drivers ?
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JohnFornaro
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« Reply #41 on: 05/01/2012 03:34 PM » |
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dealing with those quantities of loose slag, without the handy effects of a large gravity well underneath them, still need to be solved, and you have not suggested any solutions to that problem.
Probably because there are many ways to do it, some of which are dependent on the metals fractionation process decision and composition. Sintering into bricks, collecting in bags, are among options. They might even be collected by Jon Goff's stickyboom. etc.
No, probably because these issues are complicated and not at all demonstrated at the necessary scales. I quite realize that Dave is not obligated to provide a sound description of these processes; neither is PRI. Mastery of these processes is the key factor for success in the hoped for business plan which goes from selling sat time to mining asteroids. Mining at the expected scale has not taken place except within the Earth's gravity well. It will be interesting to find out how they plan to do it.
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strangeluck
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« Reply #42 on: 05/01/2012 03:37 PM » |
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Voting asteroids... The Moon may have much more overall to offer long term, I think asteroids are the low-hanging fruit.
1. My understanding is, on Earth, all the heavy metals were drawn to the core while the planet was still molten. What we mine on the surface was deposited by asteroids and comets after the crust hardened. I assume the same thing happened on the Moon. Might as well get the good stuff from the source.
2. Much less gravity well to soak up profit.
Rooting for both to succeed however!
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robertross
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« Reply #43 on: 05/01/2012 03:46 PM » |
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Neither for me.
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savuporo
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« Reply #44 on: 05/01/2012 03:50 PM » |
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Mining at the expected scale has not taken place except within the Earth's gravity well. It will be interesting to find out how they plan to do it.
I think its important to acknowledge that any mining op is at least a decade in the future. There is plenty of time to work on technology development and try a few different approaches. I bet they do not have any single plan selected yet, it would be way too premature.
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