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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote on Tue, 28 May 2019
07:03:31 -0400: In article , says... At any rate, once you reduce launch costs to put a reasonable amount of equipment on the moon to start production of LH2/LOX in quantity, you need to compare the new, lower, cost of launching LH2/LOX (or better yet, methane/LOX) from earth to that mined on the moon. If you take into account all the money it's going to take to maintain that (expensive) infrastructure on the moon to produce that propellant, I'm not convinced that it's going to break even in terms of the economics in the next 25 years or so. So Mars is right out, then, since in situ fuel production is so hard and it's REQUIRED if you're going to do Mars? The difference is in the effort that the in-situ propellant production requires. On Mars, you've got some filters and vacuum pumps to pull in CO2 from the thin atmosphere and your gas processing equipment that can be located inside the landing craft (protected from the elements). On the moon, we don't really know what we'll need to produce water in quantity. Some people think it will be as easy as scooping up some loose surface material from the lunar south pole area and baking it so that the volatiles (mostly water) come out. I think that's going to be a lot harder than it seems since we have zero actual surface data on the properties of said surface material that is "high" in water content. Add in the abrasive nature of the lunar regolith and you have a recipe for constant breakdowns of equipment exposed to that regolith. I think you overestimate the difficulty. Solid ice reflections have been observed at the lunar south pole, which means getting the water can be much easier than what you describe, which is how to extract water bonded to regolith. The 'bake me a river' approach requires moving a tonne of surface material for a liter of water. You need to 'mine' several orders of magnitude less material to get water at the concentrations indicated in shadowed areas at the south pole. IMHO, lunar in-situ LH2/LOX production will be at least an order of magnitude harder (which means more expensive) than in-situ methane/LOX production on Mars done with LH2 brought from earth. Again, I think you overestimate the difficulty of the LH2/LOX production. All it takes is local water and electricity. Bringing the LH2 from earth makes the initial process much easier for those first Mars missions. Later missions can likely get their H2O from Mars as well, but it's not strictly necessary, so this provides for one more stepping stone on the path. Hauling all that LH2 all that way seems silly to me, particularly given that vehicles like Starship don't really have any tankage for it and you're going to need a ****load of it to make enough methane to refuel Starship. It takes 240 tonnes of liquid methane to refuel Starship. That means you'd need to bring along 60 tonnes of LH2 for each Starship vehicle. Total cargo capacity of the vehicle is around 100 tonnes. The danger of NASA's architecture is that we wind up with LH2/LOX fueled vehicles because we're fueling them at L2 from lunar sources and then are funneled into the more difficult (but not an order of magnitude more difficult) production of LH2. I think it's pretty obvious that we're going to have to mine ice for hydrogen to make Mars feasible. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote on Wed, 29 May 2019
07:10:08 -0400: In article , says... Jeff Findley wrote on Tue, 28 May 2019 07:03:31 -0400: In article , says... At any rate, once you reduce launch costs to put a reasonable amount of equipment on the moon to start production of LH2/LOX in quantity, you need to compare the new, lower, cost of launching LH2/LOX (or better yet, methane/LOX) from earth to that mined on the moon. If you take into account all the money it's going to take to maintain that (expensive) infrastructure on the moon to produce that propellant, I'm not convinced that it's going to break even in terms of the economics in the next 25 years or so. So Mars is right out, then, since in situ fuel production is so hard and it's REQUIRED if you're going to do Mars? The difference is in the effort that the in-situ propellant production requires. On Mars, you've got some filters and vacuum pumps to pull in CO2 from the thin atmosphere and your gas processing equipment that can be located inside the landing craft (protected from the elements). On the moon, we don't really know what we'll need to produce water in quantity. Some people think it will be as easy as scooping up some loose surface material from the lunar south pole area and baking it so that the volatiles (mostly water) come out. I think that's going to be a lot harder than it seems since we have zero actual surface data on the properties of said surface material that is "high" in water content. Add in the abrasive nature of the lunar regolith and you have a recipe for constant breakdowns of equipment exposed to that regolith. I think you overestimate the difficulty. Possibly. It would be great if lunar water is cheap and easy to harvest. But that has yet to be proven. But there's pretty good evidence that it will be. Solid ice reflections have been observed at the lunar south pole, which means getting the water can be much easier than what you describe, which is how to extract water bonded to regolith. Solid ice of what purity? How much abrasive lunar regolith is frozen in that water? It has to be relatively pure or else it would give the kind of reflections that have been detected. Since we're operating in vacuum, don't you have to mine the frozen bits and keep them frozen until you put them in a sealed chamber to melt/bake out the water? If the water/mud melts before you get it into a chamber, all of the water will be lost to vacuum, will it not? True, but that's not exactly rocket science of any difficult kind. 'Mine' in this case amounts to essentially what you'd do to 'mine' an iceberg here on Earth. The 'bake me a river' approach requires moving a tonne of surface material for a liter of water. You need to 'mine' several orders of magnitude less material to get water at the concentrations indicated in shadowed areas at the south pole. True, but it's the 'mining' bit that's never been done with frozen water that's likely mixed in with abrasive lunar regolith. Sure there could be crystal clear lakes of frozen water at the south pole (I'd give that a snowball's chance in hell). Then obviously manned space flight is just too difficult and pointless and we should give it up. Or, more reasonably IMHO, there could be the equivalent of frozen hyper abrasive lunar mud at the south pole. That wouldn't give the sort of reflections that have been detected. Without going there, taking core samples, and analyzing the crap out of them, we simply do not know exactly what we're dealing with. You have to start somewhere. NOBODY has said to start right out building fuel factories for the Moon. Note that people HAVE said that for Mars and the same problems exist there. Since we don't know the properties of the material yet, I don't see how we can reasonably engineer machines that we know are going to be reliable at mining it in quantity. Well then Mars is right out, because unlike the Moon you just can't do manned flights to Mars and come back without in situ fuel production and we can't do that until we go there and analyze the crap out of the atmosphere. IMHO, lunar in-situ LH2/LOX production will be at least an order of magnitude harder (which means more expensive) than in-situ methane/LOX production on Mars done with LH2 brought from earth. Again, I think you overestimate the difficulty of the LH2/LOX production. All it takes is local water and electricity. And I think you might be underestimating the difficulty of obtaining lunar water in quantity. We'll have to agree to disagree on this point until we can get actual samples of south pole "water" to analyze. They say the data don't lie, but unfortunately, we really don't have all of the necessary data. You want data? We have more than you apparently think we do. From the chief scientist of the LCROSS experiment, Anthony Colaprete, from Nasa's Ames Research Center: "There's not one flavour of water on the Moon; there's a range of everything from relatively pure ice all the way to adsorbed water." You apparently only believe in that last category. He goes on to say, "And here is an instance inside Cabeus crater where it appears we threw up a range of fine-grained particulates of near pure crystalline water-ice." So does that data alter your pesimistic views about difficulty? -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Alain Fournier wrote on Wed, 29 May 2019
20:02:49 -0400: On May/29/2019 at 15:56, Fred J. McCall wrote : Jeff Findley wrote on Wed, 29 May 2019 07:10:08 -0400: In article , says... Jeff Findley wrote on Tue, 28 May 2019 07:03:31 -0400: In article , says... At any rate, once you reduce launch costs to put a reasonable amount of equipment on the moon to start production of LH2/LOX in quantity, you need to compare the new, lower, cost of launching LH2/LOX (or better yet, methane/LOX) from earth to that mined on the moon. If you take into account all the money it's going to take to maintain that (expensive) infrastructure on the moon to produce that propellant, I'm not convinced that it's going to break even in terms of the economics in the next 25 years or so. So Mars is right out, then, since in situ fuel production is so hard and it's REQUIRED if you're going to do Mars? The difference is in the effort that the in-situ propellant production requires. On Mars, you've got some filters and vacuum pumps to pull in CO2 from the thin atmosphere and your gas processing equipment that can be located inside the landing craft (protected from the elements). On the moon, we don't really know what we'll need to produce water in quantity. Some people think it will be as easy as scooping up some loose surface material from the lunar south pole area and baking it so that the volatiles (mostly water) come out. I think that's going to be a lot harder than it seems since we have zero actual surface data on the properties of said surface material that is "high" in water content. Add in the abrasive nature of the lunar regolith and you have a recipe for constant breakdowns of equipment exposed to that regolith. I think you overestimate the difficulty. Possibly. It would be great if lunar water is cheap and easy to harvest. But that has yet to be proven. But there's pretty good evidence that it will be. Solid ice reflections have been observed at the lunar south pole, which means getting the water can be much easier than what you describe, which is how to extract water bonded to regolith. Solid ice of what purity? How much abrasive lunar regolith is frozen in that water? It has to be relatively pure or else it would give the kind of reflections that have been detected. Since we're operating in vacuum, don't you have to mine the frozen bits and keep them frozen until you put them in a sealed chamber to melt/bake out the water? If the water/mud melts before you get it into a chamber, all of the water will be lost to vacuum, will it not? True, but that's not exactly rocket science of any difficult kind. 'Mine' in this case amounts to essentially what you'd do to 'mine' an iceberg here on Earth. The 'bake me a river' approach requires moving a tonne of surface material for a liter of water. You need to 'mine' several orders of magnitude less material to get water at the concentrations indicated in shadowed areas at the south pole. True, but it's the 'mining' bit that's never been done with frozen water that's likely mixed in with abrasive lunar regolith. Sure there could be crystal clear lakes of frozen water at the south pole (I'd give that a snowball's chance in hell). Then obviously manned space flight is just too difficult and pointless and we should give it up. Or, more reasonably IMHO, there could be the equivalent of frozen hyper abrasive lunar mud at the south pole. That wouldn't give the sort of reflections that have been detected. Without going there, taking core samples, and analyzing the crap out of them, we simply do not know exactly what we're dealing with. You have to start somewhere. NOBODY has said to start right out building fuel factories for the Moon. Note that people HAVE said that for Mars and the same problems exist there. Since we don't know the properties of the material yet, I don't see how we can reasonably engineer machines that we know are going to be reliable at mining it in quantity. Well then Mars is right out, because unlike the Moon you just can't do manned flights to Mars and come back without in situ fuel production and we can't do that until we go there and analyze the crap out of the atmosphere. We know what is in the Martian atmosphere. We know how to extract fuel from it. Well, no, we don't, in any effective way, unless your plan is to use up over half your cargo capacity hauling LH2 to Mars. And you're going to need water for your people. If you're going to do more than 'flags and footprints' (and you are, because you can't make fuel for the return trip fast enough), you need two years or so of water per person you send. That's around a tonne and a half of water per person. That hundred tonnes of cargo per ship is going fast... And if your plan is to use in situ water (and pretty much every plan includes that as a requirement) you're going to have to build that water extraction plant that you can't know how to build until you go and analyze the hell out of everything (according to Jeff) but you can't go do THAT until you can build a water plant. IMHO, lunar in-situ LH2/LOX production will be at least an order of magnitude harder (which means more expensive) than in-situ methane/LOX production on Mars done with LH2 brought from earth. Again, I think you overestimate the difficulty of the LH2/LOX production. All it takes is local water and electricity. And I think you might be underestimating the difficulty of obtaining lunar water in quantity. We'll have to agree to disagree on this point until we can get actual samples of south pole "water" to analyze. They say the data don't lie, but unfortunately, we really don't have all of the necessary data. You want data? We have more than you apparently think we do. From the chief scientist of the LCROSS experiment, Anthony Colaprete, from Nasa's Ames Research Center: "There's not one flavour of water on the Moon; there's a range of everything from relatively pure ice all the way to adsorbed water." You apparently only believe in that last category. He goes on to say, "And here is an instance inside Cabeus crater where it appears we threw up a range of fine-grained particulates of near pure crystalline water-ice." So does that data alter your pesimistic views about difficulty? The question is how much relatively pure ice there is. Fine-grained particulates of near pure crystalline water-ice isn't necessarily easy to mine. We have fine-grained particulates of near pure gold at many places on Earth that aren't mined. We don't fail to 'mine' that gold because it's impossibly difficult. We don't mine it because there are much easier deposits to get. And a kilo of gold probably wouldn't be enough to pay for a kilo of Earth water transported to the Moon. Note that 'mining' water on the Moon will work this way, too. There will be easier 'deposits' and harder 'deposits'. We'll 'mine' the easier ones. That's why the interest in the south pole, by the way. That's where current data indicates the 'easier' deposits of ice probably are. I'm not saying that you are completely off the mark here. It might be that water will be easy to mine on the moon. But we don't know that yet. Let me adjust that slightly. I don't necessarily think it will be 'easy'. I just think it will wind up being a lot easier than Jeff thinks it is. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
In article ,
says... Without going there, taking core samples, and analyzing the crap out of them, we simply do not know exactly what we're dealing with. You have to start somewhere. NOBODY has said to start right out building fuel factories for the Moon. Note that people HAVE said that for Mars and the same problems exist there. This is not true, IMHO. Mars atmosphere is about 95% CO2, 2% argon, 2% nitrogen, and trace amounts of other stuff. It's the 95% CO2 that would be useful to combine with LH2 brought from earth to make methane and O2. This would be via the Sabatier reaction and hydrolysis of the water coming out of the Sabatier reaction. This is all relatively simple. You're assuming that obtaining water on the moon will be as simple as mining an iceberg. I personally doubt that the water on the moon is nearly as pure as the iceberg. And even if it is, it's not certain to be on the surface and as easy to get to as you assert, at least according to this quote: Ice deposits found at Moon's pole By Paul Rincon , Science reporter, BBC News, The Woodlands, Texas http://news.bbc.co.uk/2/hi/science/nature/8544635.stm "It is mostly pure water-ice," said Dr Spudis. "It could be under a few tens of centimetres of dry regolith (lunar soil)." Again, it's that abrasive "lunar soil" that's the problem on the moon. It's going to cause lots of wear and tear on machinery. This issue simply does not exist when extracting CO2 from Mars atmosphere. And again, I think we'll have to agree to disagree since we don't know for sure how easy it will be to get to that "mostly pure water-ice". All we have right now is spectral and radar data. We have no frozen core samples to very carefully analyze in an earth based laboratory. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote:
So how much abrasive lunar regolith would we need to drive through to get to the "relatively pure ice"? We don't really know. And just how pure is "relatively pure" when we find the best deposits possible? This water ice is pure relative to what? Do you really need to move the mud? Say, something like a dome open to the ground with a radiative heatsource and a cold trap behind it. -- Mvh./Regards, Niels Jørgen Kruse, Vanløse, Denmark |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote on Thu, 30 May 2019
07:17:21 -0400: In article , says... Without going there, taking core samples, and analyzing the crap out of them, we simply do not know exactly what we're dealing with. You have to start somewhere. NOBODY has said to start right out building fuel factories for the Moon. Note that people HAVE said that for Mars and the same problems exist there. This is not true, IMHO. Mars atmosphere is about 95% CO2, 2% argon, 2% nitrogen, and trace amounts of other stuff. It's the 95% CO2 that would be useful to combine with LH2 brought from earth to make methane and O2. So you're going to give up over 60% of your cargo capacity to haul LH2 to Mars? Presumably you also have to take two years worth of water for every person you're sending, plus two years worth of food, plus at least six months worth of oxygen, plus... You get the idea. Suddenly Starship looks mighty small. This would be via the Sabatier reaction and hydrolysis of the water coming out of the Sabatier reaction. This is all relatively simple. Not as simple as heating stuff and capturing the vapor. You're assuming that obtaining water on the moon will be as simple as mining an iceberg. Where did I say any such thing? Several orders of magnitude easier than the impossibility you keep claiming still leaves lots of space before we're at "mining an iceberg". I personally doubt that the water on the moon is nearly as pure as the iceberg. And even if it is, it's not certain to be on the surface and as easy to get to as you assert, at least according to this quote: Ice deposits found at Moon's pole By Paul Rincon , Science reporter, BBC News, The Woodlands, Texas http://news.bbc.co.uk/2/hi/science/nature/8544635.stm "It is mostly pure water-ice," said Dr Spudis. "It could be under a few tens of centimetres of dry regolith (lunar soil)." Then again, it 'could' not be. Again, it's that abrasive "lunar soil" that's the problem on the moon. It's going to cause lots of wear and tear on machinery. This issue simply does not exist when extracting CO2 from Mars atmosphere. You act like regolith is some sort of magical super-abrasive. It's not. Is it abrasive? Sure. Can it be dealt with? Of course, by a number of different mitigations. And it's not regolith that's the problem and it's not particularly abrasive. The problem is that mechanical processes that have produced existing dust. Regolith is handy for all sorts of things. We've made concrete out of it. And again, I think we'll have to agree to disagree since we don't know for sure how easy it will be to get to that "mostly pure water-ice". All we have right now is spectral and radar data. We have no frozen core samples to very carefully analyze in an earth based laboratory. You seem bound and determined to accentuate the problems. I can only attribute this to you wanting to 'skip' the Moon because you think it's a distraction from getting to Mars, because the data doesn't really support opposition of the magnitude you put forward. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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