SpaceX Mars and Moon Colonization with titanium alloy bulldozers and materials processing

Craig Davidson gave a talk in 2017 about Improving the SpaceX Mars Colonization Plans.

Make a moon and Mars capable bulldozer. Replace steel with titanium-aluminum alloy. Use electric battery technology and solar panels.

Astrobotic developed Polaris as an excavation vehicle that could serve as a robotic precursor to future human planetary colonization efforts by preparing terrain and mining ice and other volatiles.

Astrobotic is developing robotic bulldozers the size of riding mowers for the moon. They could prepare a safe landing site for NASA’s lunar outpost by surrounding it with an eight-foot high semi-circle berm to block grit kicked out by spacecraft landings from hitting nearby habitats.

A moon base with each square being about 40 feet by 40 feet would have massive smelters to process regolith to pure metals and components.

SharkFin Magnetic Sail

He also proposed the SharkFin Magnetic Sail at the 20th Annual International Mars Society Convention, held at University of California Irvine from Sept 7-10, 2017.

The SharkFin Magnetic Sail combines the Lorentz Force law, Faraday’s law, and Lenz’s law to harvest propulsive force and electrical charge from large-scale electromagnetic fields such as the Magnetosphere, Heliosphere, or Interstellar Magnetic Field (ISMF). Advances in superconducting cable design, including a self-insulating cable patented by Dark Sea Industries (patent pending), allows combining the benefits of electric/magnetic sails with advances in low voltage high current carrying capacity superconducting cables to provide a system which provides both power and propulsion to the spacecraft. The synthetic magnetosphere which envelopes the craft can eliminating exposure to charged radiation, leaving only neutral radiation to be absorbed by a shield (such as water ice). Magnetic sails are thus seen as the power/propulsion system of choice for interplanetary spacecraft.

The SharkFin magnetic sail is a revolutionary advance in deep space propulsion. In one sense, it is a solar powered power system and solar powered propulsion system, at very high rates of speed, and very high levels of power. It has a comparatively low mass implementation with no fuel requirement (other than for coil charging), since it harvests velocity directly from the solar wind (or a magnetosphere), without the huge coils and deployment complications of traditional magsail/plasmasail designs. It is perfectly suited to be one of the propulsion systems aboard an Aldrin Cycler type craft. It uses a different style of navigation, with more indirect routes than traditional direct thrust paths, but given the other benefits (and given the higher speed, shorter times to target) it will come to dominate deep space propulsion in the years ahead.

73 thoughts on “SpaceX Mars and Moon Colonization with titanium alloy bulldozers and materials processing”

  1. The aldrin cycler is a flawed design. Bulldozers would have to be used perpetually unless in combination sintering robots are used after neither one would have to be used that often then. What happens to interstellar when you get away from solar winds unless you reached full speed and coast. Then what slows it down solar wind from other star. Prob not. Seems like its an accelerant.

    Reply
  2. The argument appears to be: There is a huge energy flow, but you need to interact with a huge volume. So to interact with a huge volume you need a very strong magnetic field that will react with the fields over a big volume. So you need heaps of current flowing around your coils. But because there is a huge energy flow, you can generate huge power using a MHD generator, from the solar wind plasma flow. So… (wave hands back and forth) you can generate the huge magnetic fields needed, by using the huge power generated, by the interaction of the ion flow with the huge magnetic field. Therefore … (Wave hands a bit more. Distract people by drawings of a spaceship based on an old F104 fighter plane (Why didn’t he just go the whole hog and base it on the Battleship Yamoto. You know he wants to.)) …you start with a small starting power source (a battery or solar PV or something) and bootstrap yourself up to a 9 GW space ship. Then (hands waving so fast now that he risks broken fingers) you can get multiple hundreds of G acceleration, and even take off from the Earth (though without ionizing the Earth’s atmosphere first I don’t see how you’d be generating the energy). What’s most bizarre is that I’m 97.3% sure that this was all laid out in old science fiction books written by Captain W.E. Johns back in the late 1950s. Yes, the same author as wrote Biggles.

    Reply
  3. The argument appears to be: There is a huge energy flow but you need to interact with a huge volume.So to interact with a huge volume you need a very strong magnetic field that will react with the fields over a big volume.So you need heaps of current flowing around your coils.But because there is a huge energy flow you can generate huge power using a MHD generator from the solar wind plasma flow.So… (wave hands back and forth) you can generate the huge magnetic fields needed by using the huge power generated by the interaction of the ion flow with the huge magnetic field.Therefore … (Wave hands a bit more. Distract people by drawings of a spaceship based on an old F104 fighter plane (Why didn’t he just go the whole hog and base it on the Battleship Yamoto. You know he wants to.)) …you start with a small starting power source (a battery or solar PV or something) and bootstrap yourself up to a 9 GW space ship.Then (hands waving so fast now that he risks broken fingers) you can get multiple hundreds of G acceleration and even take off from the Earth (though without ionizing the Earth’s atmosphere first I don’t see how you’d be generating the energy).What’s most bizarre is that I’m 97.3{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} sure that this was all laid out in old science fiction books written by Captain W.E. Johns back in the late 1950s. Yes the same author as wrote Biggles.

    Reply
  4. Yeah the reduction of oxides via hydrogen you listed sounded familiar 😉 you basically have a carbothermal process combined with hydrogen reduction to further liberate oxygen. I’m not sure if 150 ppm is enough, and then sifting through the dust to get it too. With ilmenite, you can at least start with the mare where it’s rich with the stuff (~10 wt%) and then magnetically separate it out. But who knows, maybe another processing method can be thought up for separating carbon from the regolith or carbonaceous asteroids with their other filler material. The TiCl4 byproduct in carbochlorination is nice because it’s just one step away from Ti while also regenerating your Cl2. I did also come across molten mixes for reducing TiO2, but it was a more involved process which required more hardware/investment compared to what I had going, so I shelved it. Still could have merit though! And, not sure about reducing TiO2 and Al with H2, but I remember you can do it with fluorinated salts at something like 1100 C.

    Reply
  5. Yeah the reduction of oxides via hydrogen you listed sounded familiar 😉 you basically have a carbothermal process combined with hydrogen reduction to further liberate oxygen. I’m not sure if 150 ppm is enough and then sifting through the dust to get it too. With ilmenite you can at least start with the mare where it’s rich with the stuff (~10 wt{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12}) and then magnetically separate it out. But who knows maybe another processing method can be thought up for separating carbon from the regolith or carbonaceous asteroids with their other filler material. The TiCl4 byproduct in carbochlorination is nice because it’s just one step away from Ti while also regenerating your Cl2. I did also come across molten mixes for reducing TiO2 but it was a more involved process which required more hardware/investment compared to what I had going so I shelved it. Still could have merit though! And not sure about reducing TiO2 and Al with H2 but I remember you can do it with fluorinated salts at something like 1100 C.

    Reply
  6. For carbon on the Moon, I was thinking to ship it from Earth for the specific purpose of making methalox. Then use the excess hydrogen to reduce oxides to recover half the water and get the byproducts. According to one of the other recent NBF articles, there are ~100-150 ppm of carbon on the Moon from the solar wind, but extracting and purifying it could be a pain. Further down the line there’s asteroid carbon from carbonaceous asteroids. That’s expected to be various hydrocarbons, so you’d get even more hydrogen excess. The same asteroids should also contain water and silicates, and maybe other oxides. The carbochlorination to get TiCl4 is interesting, but there may be another option. If you google for “titanium oxide hydrogen reduction”, the first result is a presentation that suggests adding other metals to directly reduce TiO2 to a titanium alloy. Their primary suggestion is nickel or platinum, but those aren’t common on the moon. Their third option is aluminum, which is ~7% of Lunar soil, probably as alumina. However, reducing alumina with hydrogen is also tricky. There are some papers that suggest it’s possible if the hydrogen is dissolved in molten aluminum. But I wonder, if alumina and TiO2 are mixed, would hydrogen be able to reduce that mixture, forming an Al-Ti alloy?

    Reply
  7. For carbon on the Moon I was thinking to ship it from Earth for the specific purpose of making methalox. Then use the excess hydrogen to reduce oxides to recover half the water and get the byproducts.According to one of the other recent NBF articles there are ~100-150 ppm of carbon on the Moon from the solar wind but extracting and purifying it could be a pain. Further down the line there’s asteroid carbon from carbonaceous asteroids. That’s expected to be various hydrocarbons so you’d get even more hydrogen excess. The same asteroids should also contain water and silicates and maybe other oxides.The carbochlorination to get TiCl4 is interesting but there may be another option. If you google for titanium oxide hydrogen reduction””” the first result is a presentation that suggests adding other metals to directly reduce TiO2 to a titanium alloy. Their primary suggestion is nickel or platinum but those aren’t common on the moon. Their third option is aluminum which is ~7{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} of Lunar soil probably as alumina. However reducing alumina with hydrogen is also tricky. There are some papers that suggest it’s possible if the hydrogen is dissolved in molten aluminum. But I wonder if alumina and TiO2 are mixed would hydrogen be able to reduce that mixture”” forming an Al-Ti alloy?”””

    Reply
  8. Oh no worries; I understand Vuukle is a fickle beast! Yes I too found that the method one used to extract water was dependent on what the goal of the operation was. Just looking for LOX? Hydrogen reduction is most efficient. Do you want more useful byproducts in addition to the LOX? Carbochlorination is then superior. Extra costs exists for the latter setup due to more hardware and maintenance, but they could be offset by the increased usability of byproducts (TiCl4 instead of TiO2). And yes, for CO reduction you got it: hydrogen from water. It’s extra steps, but the alternative is bringing a whole bunch of H2 along. However, one downside is bringing the CO along with. There is a way to recycle the CO back at the cost of reduced methane output, though. I also did start to look at pros/cons to grabbing carbon from the environment in as much the way as you were talking about here (which really sparked my first comment), but then there are purity issues to consider and I just had a lack of time at that point as deadlines approached.

    Reply
  9. Oh no worries; I understand Vuukle is a fickle beast!Yes I too found that the method one used to extract water was dependent on what the goal of the operation was. Just looking for LOX? Hydrogen reduction is most efficient. Do you want more useful byproducts in addition to the LOX? Carbochlorination is then superior. Extra costs exists for the latter setup due to more hardware and maintenance but they could be offset by the increased usability of byproducts (TiCl4 instead of TiO2). And yes for CO reduction you got it: hydrogen from water. It’s extra steps but the alternative is bringing a whole bunch of H2 along. However one downside is bringing the CO along with. There is a way to recycle the CO back at the cost of reduced methane output though. I also did start to look at pros/cons to grabbing carbon from the environment in as much the way as you were talking about here (which really sparked my first comment) but then there are purity issues to consider and I just had a lack of time at that point as deadlines approached.

    Reply
  10. The argument appears to be: There is a huge energy flow, but you need to interact with a huge volume.
    So to interact with a huge volume you need a very strong magnetic field that will react with the fields over a big volume.
    So you need heaps of current flowing around your coils.
    But because there is a huge energy flow, you can generate huge power using a MHD generator, from the solar wind plasma flow.
    So… (wave hands back and forth) you can generate the huge magnetic fields needed, by using the huge power generated, by the interaction of the ion flow with the huge magnetic field.

    Therefore … (Wave hands a bit more. Distract people by drawings of a spaceship based on an old F104 fighter plane (Why didn’t he just go the whole hog and base it on the Battleship Yamoto. You know he wants to.)) …you start with a small starting power source (a battery or solar PV or something) and bootstrap yourself up to a 9 GW space ship.

    Then (hands waving so fast now that he risks broken fingers) you can get multiple hundreds of G acceleration, and even take off from the Earth (though without ionizing the Earth’s atmosphere first I don’t see how you’d be generating the energy).

    What’s most bizarre is that I’m 97.3% sure that this was all laid out in old science fiction books written by Captain W.E. Johns back in the late 1950s. Yes, the same author as wrote Biggles.

    Reply
  11. To clarify the alternatives with CO and ilmenite, as I understand them, your approach: 1. CO plus FeTiO3 –> CO2 + Fe + TiO2 2. 4 H2O –> 4 H2 plus 2 O2 3. CO2 plus 4 H2 –> CH4 + 2 H2O Vs my approach: 1. 4 H2O –> 4 H2 plus 2 O2 (same amount of oxygen needed for methalox) 2. C plus 2 H2 –> CH4 3. 2 FeTiO3 plus 2 H2 –> 2 Fe + 2 TiO2 + 2H2O Ok, it the same amount of steps in this case. I end up using twice as much ilmenite, since I’m using C and not CO. (Sorry about the spelled out “plus”s – Vuukle stripped the mathematical plus symbols last time I tried.)

    Reply
  12. To clarify the alternatives with CO and ilmenite as I understand them your approach:1. CO plus FeTiO3 –> CO2 + Fe + TiO22. 4 H2O –> 4 H2 plus 2 O23. CO2 plus 4 H2 –> CH4 + 2 H2OVs my approach:1. 4 H2O –> 4 H2 plus 2 O2 (same amount of oxygen needed for methalox)2. C plus 2 H2 –> CH43. 2 FeTiO3 plus 2 H2 –> 2 Fe + 2 TiO2 + 2H2OOk it the same amount of steps in this case. I end up using twice as much ilmenite since I’m using C and not CO.(Sorry about the spelled out plus””s – Vuukle stripped the mathematical plus symbols last time I tried.)”””

    Reply
  13. Yes, my starting point was a carbon source of some kind, plus water. In principle some or all of the oxygen can come from other sources, but then the question is where from, and how do you extract it from there? To that, my basic approach is a two-step process: 1. Carbon plus water –> methalox plus excess hydrogen, as above; 2. React the excess hydrogen with the alternative oxygen source (typically some sort of oxide), to recover some of the water. In some cases you can extract the oxygen more directly, but as I replied to Brett, which approach is better depends on the details. In the case of CO2, the CO2 itself acts as an oxide, and indeed when you do a Sabatier reaction, half of the hydrogen reacts with the oxygen from CO2 to recover water. I’m curious about the reaction in your last paragraph. Are you suggesting reacting CO with ilmenite? I would expect this should produce TiO2, Fe, and *CO2*, not O2. And I don’t see how you’d get methane, since there’s no hydrogen in either ilmenite nor CO. If you’re getting the hydrogen from water, then it’s the same as the process I suggested above, but with an extra step. You end up splitting just as much water to convert the CO2 to methane, and you recover half of it in the Sebatier reaction. You may as well go my way, and react the excess hydrogen with ilmenite directly, to recover the same amount of water. Finally, where are you getting the CO from? If you’re shipping from Earth, it makes more sense to ship pure carbon. That way you save the weight of the oxygen.

    Reply
  14. Yes my starting point was a carbon source of some kind plus water.In principle some or all of the oxygen can come from other sources but then the question is where from and how do you extract it from there? To that my basic approach is a two-step process:1. Carbon plus water –> methalox plus excess hydrogen as above;2. React the excess hydrogen with the alternative oxygen source (typically some sort of oxide) to recover some of the water.In some cases you can extract the oxygen more directly but as I replied to Brett which approach is better depends on the details. In the case of CO2 the CO2 itself acts as an oxide and indeed when you do a Sabatier reaction half of the hydrogen reacts with the oxygen from CO2 to recover water.I’m curious about the reaction in your last paragraph. Are you suggesting reacting CO with ilmenite? I would expect this should produce TiO2 Fe and *CO2* not O2. And I don’t see how you’d get methane since there’s no hydrogen in either ilmenite nor CO.If you’re getting the hydrogen from water then it’s the same as the process I suggested above but with an extra step. You end up splitting just as much water to convert the CO2 to methane and you recover half of it in the Sebatier reaction. You may as well go my way and react the excess hydrogen with ilmenite directly to recover the same amount of water.Finally where are you getting the CO from? If you’re shipping from Earth it makes more sense to ship pure carbon. That way you save the weight of the oxygen.

    Reply
  15. I didn’t find the physics terribly persuasive, but the links I found doing that search didn’t go into much detail. The basic problem, of course, is that in order to take much momentum off the solar wind and the magnetic fields it carries, you need to interact with a huge volume, as the density is pretty low. It isn’t easy for compact devices to interact with huge volumes this way.

    Reply
  16. I didn’t find the physics terribly persuasive but the links I found doing that search didn’t go into much detail.The basic problem of course is that in order to take much momentum off the solar wind and the magnetic fields it carries you need to interact with a huge volume as the density is pretty low. It isn’t easy for compact devices to interact with huge volumes this way.

    Reply
  17. Ahhh I see, you’re using liberated oxygen from the ISRU’ed water to enable combustion rather than supplying it yourself. Reason for all the questions is that I did a high level pass using ilmenite as the feed and a few different reactions to see which one was best. One used CO, which gave TiO2, Fe, O2, and if you liberated a little extra, CH4.

    Reply
  18. Ahhh I see you’re using liberated oxygen from the ISRU’ed water to enable combustion rather than supplying it yourself. Reason for all the questions is that I did a high level pass using ilmenite as the feed and a few different reactions to see which one was best. One used CO which gave TiO2 Fe O2 and if you liberated a little extra CH4.

    Reply
  19. Add to that the issue of teleoperating something so far away. Self replication and AI will work great for the solar system one day but until then testing these concepts with very limited time delay and ‘reasonably’ quick resupply of parts from the motherplanet makes the Moon an ideal mining target.

    Reply
  20. Add to that the issue of teleoperating something so far away. Self replication and AI will work great for the solar system one day but until then testing these concepts with very limited time delay and ‘reasonably’ quick resupply of parts from the motherplanet makes the Moon an ideal mining target.

    Reply
  21. Yeah the reduction of oxides via hydrogen you listed sounded familiar 😉 you basically have a carbothermal process combined with hydrogen reduction to further liberate oxygen.

    I’m not sure if 150 ppm is enough, and then sifting through the dust to get it too. With ilmenite, you can at least start with the mare where it’s rich with the stuff (~10 wt%) and then magnetically separate it out. But who knows, maybe another processing method can be thought up for separating carbon from the regolith or carbonaceous asteroids with their other filler material.

    The TiCl4 byproduct in carbochlorination is nice because it’s just one step away from Ti while also regenerating your Cl2. I did also come across molten mixes for reducing TiO2, but it was a more involved process which required more hardware/investment compared to what I had going, so I shelved it. Still could have merit though! And, not sure about reducing TiO2 and Al with H2, but I remember you can do it with fluorinated salts at something like 1100 C.

    Reply
  22. I’ll add that a key question is the optimal temperatures and pressures for each reaction, since heating and pressurization add energy costs and change the thermodynamics. There’s also the electric efficiency of the different electrochemical processes. Salts and oxides often have high melting temperatures, but hydrogen reduction could maybe be done at lower temperature (but maybe not). Water can be split fairly easily at as low as 1 C, but it’s more efficient at higher temperatures. Then you have various catalysts, which change the picture again. The devil is in the details.

    Reply
  23. I’ll add that a key question is the optimal temperatures and pressures for each reaction since heating and pressurization add energy costs and change the thermodynamics. There’s also the electric efficiency of the different electrochemical processes.Salts and oxides often have high melting temperatures but hydrogen reduction could maybe be done at lower temperature (but maybe not). Water can be split fairly easily at as low as 1 C but it’s more efficient at higher temperatures. Then you have various catalysts which change the picture again. The devil is in the details.

    Reply
  24. No, that’s the point: if you *stoichiometrically* split just enough water to make your oxygen, you end up with more hydrogen than you need to make the matching amount of methane. You can think of it this way: When you burn the methane, part of the oxygen reacts with the methane’s hydrogens to form back water. But the rest of the oxygen reacts with the carbon (forming CO2). Where did that extra oxygen come from? If it came also from water, then you have a matching amount of hydrogen left over, which isn’t in the methane. Write down the burn and synthesis equations yourself, and balance them out. Try that with different carbon sources, and you’ll see that for any carbon source less oxidized than CO2 (graphite, hydrocarbons, even CO), you end up with excess hydrogen.

    Reply
  25. No that’s the point: if you *stoichiometrically* split just enough water to make your oxygen you end up with more hydrogen than you need to make the matching amount of methane.You can think of it this way:When you burn the methane part of the oxygen reacts with the methane’s hydrogens to form back water. But the rest of the oxygen reacts with the carbon (forming CO2). Where did that extra oxygen come from? If it came also from water then you have a matching amount of hydrogen left over which isn’t in the methane.Write down the burn and synthesis equations yourself and balance them out. Try that with different carbon sources and you’ll see that for any carbon source less oxidized than CO2 (graphite hydrocarbons even CO) you end up with excess hydrogen.

    Reply
  26. I think the key here, and throughout the solar system, is the development and use of Von Neumann machines. “Clunking replicators”. It’s uneconomical if you’re using people to run your factory. If you just have to plop a 100, or even a 1000 tons of equipment on the Moon, and it goes on multiplying itself without human labor, return on investment will be sky high even if the first factory costs a million dollars a pound. This is the one technological advance we need to conquer space. It’s what we should concentrate on.

    Reply
  27. I think the key here and throughout the solar system is the development and use of Von Neumann machines. Clunking replicators””. It’s uneconomical if you’re using people to run your factory. If you just have to plop a 100″” or even a 1000 tons of equipment on the Moon and it goes on multiplying itself without human labor”” return on investment will be sky high even if the first factory costs a million dollars a pound.This is the one technological advance we need to conquer space. It’s what we should concentrate on.”””

    Reply
  28. NO! I started listening more closely to Davidson’s talk, and checked out the paper. It is NOT an ion-powered drive, it is somehow a ‘magnetic field’ drive, and he is claiming it can get continuous 1G acceleration to Mars – accelerating and then decelerating! The paper even mentions how they’ll have to LIMIT acceleration to avoid crushing humans on board! This is why he was showing pictures of densely packed airline-seats in his “Big Star” ‘cycler’, which would be absurd for a multi-month transit. He’s aiming at a few days to Mars!!!! He even proposes using this for propelling a second stage to orbit without rockets! I have to be extremely skeptical of this ‘shark fin magnetic sail’ – sounds way too good to be true, and way to good to have been overlooked for so long, even given (as he says) new understanding of the solar (and Earth) electrical and magnetic environments. But if it DID work – forget ’em-drive’, this is flying saucer stuff! Also – since I can’t give a link – search “Dark Sea Industries Indiegogo” for their kickstarter attempt from a few years back, and a lot more detail of what they’re thinking.

    Reply
  29. NO! I started listening more closely to Davidson’s talk and checked out the paper. It is NOT an ion-powered drive it is somehow a ‘magnetic field’ drive and he is claiming it can get continuous 1G acceleration to Mars – accelerating and then decelerating! The paper even mentions how they’ll have to LIMIT acceleration to avoid crushing humans on board! This is why he was showing pictures of densely packed airline-seats in his Big Star”” ‘cycler'”” which would be absurd for a multi-month transit. He’s aiming at a few days to Mars!!!! He even proposes using this for propelling a second stage to orbit without rockets!I have to be extremely skeptical of this ‘shark fin magnetic sail’ – sounds way too good to be true and way to good to have been overlooked for so long even given (as he says) new understanding of the solar (and Earth) electrical and magnetic environments. But if it DID work – forget ’em-drive'”” this is flying saucer stuff!Also – since I can’t give a link – search “”””Dark Sea Industries Indiegogo”””” for their kickstarter attempt from a few years back”””” and a lot more detail of what they’re thinking.”””

    Reply
  30. For carbon on the Moon, I was thinking to ship it from Earth for the specific purpose of making methalox. Then use the excess hydrogen to reduce oxides to recover half the water and get the byproducts.

    According to one of the other recent NBF articles, there are ~100-150 ppm of carbon on the Moon from the solar wind, but extracting and purifying it could be a pain. Further down the line there’s asteroid carbon from carbonaceous asteroids. That’s expected to be various hydrocarbons, so you’d get even more hydrogen excess. The same asteroids should also contain water and silicates, and maybe other oxides.

    The carbochlorination to get TiCl4 is interesting, but there may be another option. If you google for “titanium oxide hydrogen reduction”, the first result is a presentation that suggests adding other metals to directly reduce TiO2 to a titanium alloy. Their primary suggestion is nickel or platinum, but those aren’t common on the moon. Their third option is aluminum, which is ~7% of Lunar soil, probably as alumina. However, reducing alumina with hydrogen is also tricky. There are some papers that suggest it’s possible if the hydrogen is dissolved in molten aluminum. But I wonder, if alumina and TiO2 are mixed, would hydrogen be able to reduce that mixture, forming an Al-Ti alloy?

    Reply
  31. Oh no worries; I understand Vuukle is a fickle beast!

    Yes I too found that the method one used to extract water was dependent on what the goal of the operation was. Just looking for LOX? Hydrogen reduction is most efficient. Do you want more useful byproducts in addition to the LOX? Carbochlorination is then superior. Extra costs exists for the latter setup due to more hardware and maintenance, but they could be offset by the increased usability of byproducts (TiCl4 instead of TiO2).

    And yes, for CO reduction you got it: hydrogen from water. It’s extra steps, but the alternative is bringing a whole bunch of H2 along. However, one downside is bringing the CO along with. There is a way to recycle the CO back at the cost of reduced methane output, though. I also did start to look at pros/cons to grabbing carbon from the environment in as much the way as you were talking about here (which really sparked my first comment), but then there are purity issues to consider and I just had a lack of time at that point as deadlines approached.

    Reply
  32. To clarify the alternatives with CO and ilmenite, as I understand them, your approach:
    1. CO plus FeTiO3 –> CO2 + Fe + TiO2
    2. 4 H2O –> 4 H2 plus 2 O2
    3. CO2 plus 4 H2 –> CH4 + 2 H2O

    Vs my approach:
    1. 4 H2O –> 4 H2 plus 2 O2 (same amount of oxygen needed for methalox)
    2. C plus 2 H2 –> CH4
    3. 2 FeTiO3 plus 2 H2 –> 2 Fe + 2 TiO2 + 2H2O

    Ok, it the same amount of steps in this case. I end up using twice as much ilmenite, since I’m using C and not CO.

    (Sorry about the spelled out “plus”s – Vuukle stripped the mathematical plus symbols last time I tried.)

    Reply
  33. Yes, my starting point was a carbon source of some kind, plus water.

    In principle some or all of the oxygen can come from other sources, but then the question is where from, and how do you extract it from there? To that, my basic approach is a two-step process:
    1. Carbon plus water –> methalox plus excess hydrogen, as above;
    2. React the excess hydrogen with the alternative oxygen source (typically some sort of oxide), to recover some of the water.

    In some cases you can extract the oxygen more directly, but as I replied to Brett, which approach is better depends on the details. In the case of CO2, the CO2 itself acts as an oxide, and indeed when you do a Sabatier reaction, half of the hydrogen reacts with the oxygen from CO2 to recover water.

    I’m curious about the reaction in your last paragraph. Are you suggesting reacting CO with ilmenite? I would expect this should produce TiO2, Fe, and *CO2*, not O2. And I don’t see how you’d get methane, since there’s no hydrogen in either ilmenite nor CO.

    If you’re getting the hydrogen from water, then it’s the same as the process I suggested above, but with an extra step. You end up splitting just as much water to convert the CO2 to methane, and you recover half of it in the Sebatier reaction. You may as well go my way, and react the excess hydrogen with ilmenite directly, to recover the same amount of water.

    Finally, where are you getting the CO from? If you’re shipping from Earth, it makes more sense to ship pure carbon. That way you save the weight of the oxygen.

    Reply
  34. I didn’t find the physics terribly persuasive, but the links I found doing that search didn’t go into much detail.

    The basic problem, of course, is that in order to take much momentum off the solar wind and the magnetic fields it carries, you need to interact with a huge volume, as the density is pretty low. It isn’t easy for compact devices to interact with huge volumes this way.

    Reply
  35. Well, yes. Except for the fact that our choice of asteroids is — for pure conservation-of-energy reasons — limited to those which are in NEO “near Earth orbiting” orbits. The bits that are from ⅓ the way to Venus to ⅓ the way to Mars. Now this is not to say that there aren’t a bunch of NEOs that’d “work”. Your next problem, after figuring out which one to go to is kind of like the Luna problem. While not particularly expected to be composed of billion-year-churned-meteoritic dusts, what we’ve seen so far is that quite a few do look like barely-stuck-together-by-gravity lumps of smaller primordial material. Who knows. Big electromagnets might be able to reach in and pull out exactly what is needed. But I’m betting the really valuable stuff still requires refining. And here is where “asteroids” in NEO orbits are a bit of a pain in the derriere: just about no gravity. To put it straight, an asteroid (not terribly big, or small) at 2 km diameter, having a density of 1,250 kg/m³ will have a surface gravity of only 44.5 micro-G’s (0.0004365 m/s² or N/kg). If you or I were to so much as jump up from a squat (achieving over 1 m/s vertical velocity), quit literally, we would have reached the escape velocity of the rock. Off we’d go… floating away forever. The same problem goes for “mining”. Almost-zero gravity isn’t helpful in keeping things put. Equipment would need to dig (somehow!) and stick claws in the surface to hold on. Even then, being mostly composed of aggregated primordial dusts and boulders, it really isn’t clear how to mechanically “mine” the thing. Just saying. Moon is simpler. And closer. And friendly. GoatGuy

    Reply
  36. Well yes. Except for the fact that our choice of asteroids is — for pure conservation-of-energy reasons — limited to those which are in NEO ear Earth orbiting”” orbits. The bits that are from ⅓ the way to Venus to ⅓ the way to Mars. Now this is not to say that there aren’t a bunch of NEOs that’d “”””work””””. Your next problem”” after figuring out which one to go to is kind of like the Luna problem. While not particularly expected to be composed of billion-year-churned-meteoritic dusts”” what we’ve seen so far is that quite a few do look like barely-stuck-together-by-gravity lumps of smaller primordial material. Who knows. Big electromagnets might be able to reach in and pull out exactly what is needed. But I’m betting the really valuable stuff still requires refining. And here is where “”””asteroids”””” in NEO orbits are a bit of a pain in the derriere: just about no gravity. To put it straight”” an asteroid (not terribly big or small) at 2 km diameter having a density of 1250 kg/m³ will have a surface gravity of only 44.5 micro-G’s (0.0004365 m/s² or N/kg). If you or I were to so much as jump up from a squat (achieving over 1 m/s vertical velocity) quit literally”” we would have reached the escape velocity of the rock. Off we’d go… floating away forever. The same problem goes for “”””mining””””. Almost-zero gravity isn’t helpful in keeping things put. Equipment would need to dig (somehow!) and stick claws in the surface to hold on. Even then”” being mostly composed of aggregated primordial dusts and boulders”” it really isn’t clear how to mechanically “”””mine”””” the thing.Just saying.Moon is simpler.And closer.And friendly. GoatGuy”””””””

    Reply
  37. Ahhh I see, you’re using liberated oxygen from the ISRU’ed water to enable combustion rather than supplying it yourself.

    Reason for all the questions is that I did a high level pass using ilmenite as the feed and a few different reactions to see which one was best. One used CO, which gave TiO2, Fe, O2, and if you liberated a little extra, CH4.

    Reply
  38. Not to be a stickler, but isn’t that just splitting more water than is stoichiometrically necessary and giving you excess? This can be done in a separate reactor under more ideal conditions to increase the efficiency of splitting water for the LOX.

    Reply
  39. Not to be a stickler but isn’t that just splitting more water than is stoichiometrically necessary and giving you excess? This can be done in a separate reactor under more ideal conditions to increase the efficiency of splitting water for the LOX.

    Reply
  40. Add to that the issue of teleoperating something so far away. Self replication and AI will work great for the solar system one day but until then testing these concepts with very limited time delay and ‘reasonably’ quick resupply of parts from the motherplanet makes the Moon an ideal mining target.

    Reply
  41. I’ll add that a key question is the optimal temperatures and pressures for each reaction, since heating and pressurization add energy costs and change the thermodynamics. There’s also the electric efficiency of the different electrochemical processes.

    Salts and oxides often have high melting temperatures, but hydrogen reduction could maybe be done at lower temperature (but maybe not). Water can be split fairly easily at as low as 1 C, but it’s more efficient at higher temperatures. Then you have various catalysts, which change the picture again. The devil is in the details.

    Reply
  42. No, that’s the point: if you *stoichiometrically* split just enough water to make your oxygen, you end up with more hydrogen than you need to make the matching amount of methane.

    You can think of it this way:
    When you burn the methane, part of the oxygen reacts with the methane’s hydrogens to form back water. But the rest of the oxygen reacts with the carbon (forming CO2). Where did that extra oxygen come from? If it came also from water, then you have a matching amount of hydrogen left over, which isn’t in the methane.

    Write down the burn and synthesis equations yourself, and balance them out. Try that with different carbon sources, and you’ll see that for any carbon source less oxidized than CO2 (graphite, hydrocarbons, even CO), you end up with excess hydrogen.

    Reply
  43. I think the key here, and throughout the solar system, is the development and use of Von Neumann machines. “Clunking replicators”.

    It’s uneconomical if you’re using people to run your factory. If you just have to plop a 100, or even a 1000 tons of equipment on the Moon, and it goes on multiplying itself without human labor, return on investment will be sky high even if the first factory costs a million dollars a pound.

    This is the one technological advance we need to conquer space. It’s what we should concentrate on.

    Reply
  44. NO! I started listening more closely to Davidson’s talk, and checked out the paper. It is NOT an ion-powered drive, it is somehow a ‘magnetic field’ drive, and he is claiming it can get continuous 1G acceleration to Mars – accelerating and then decelerating! The paper even mentions how they’ll have to LIMIT acceleration to avoid crushing humans on board!

    This is why he was showing pictures of densely packed airline-seats in his “Big Star” ‘cycler’, which would be absurd for a multi-month transit. He’s aiming at a few days to Mars!!!! He even proposes using this for propelling a second stage to orbit without rockets!

    I have to be extremely skeptical of this ‘shark fin magnetic sail’ – sounds way too good to be true, and way to good to have been overlooked for so long, even given (as he says) new understanding of the solar (and Earth) electrical and magnetic environments. But if it DID work – forget ’em-drive’, this is flying saucer stuff!

    Also – since I can’t give a link – search “Dark Sea Industries Indiegogo” for their kickstarter attempt from a few years back, and a lot more detail of what they’re thinking.

    Reply
  45. My fellow Goats… • Bulldozers • Giant smelting plants • Humungous algae farms • Megatons of off-Lunar material • Hundreds of gigawatts of power • Profoundly lethal failure modes • ZERO¹ hydrothermal concentration of ores • 32,842 billion square meters … of unexplored surface We found that there is no significant area of Luna which isn’t covered in an over-layer of meteoritically churned dusts; churned over billions of years, smashed to flinders, abrasive as hêll, completely mixed down to the µm level. Remarkably mixed. Now while it is FUN (and who knows, for people writing reports, profitable!) to imagine being there, digging stuff up, carting it to the refining facility, loading it in hoppers, magnetically and using density, electric fields, “pointiness” and so on, separating the dusts into big old piles of separated “ore”, then taking said ores and somehow energy-efficiently refining and reducing these to metals, gasses, elements, other compounds; stockpiling THESE and then re-blending and re-mixing them in novel (but not difficult or exotic) Lunar-oriented molecular programming processes … while that is all fun to imagine, several things need first to be established: • (1) A real profit motivation • (2) Scope of economic investment before “break even” • (3) The “sellable” pölïtical narrative to heavily tax the Nation. • (4) Buy-in by international community • (5) Buy-in by academic community • (6) Mandate for the new Space Force … in no uncertain terms • (7) Scope of supporting Earthside infrastructure, costs, personnel • (8) Legal basis for claiming “property” and IP rights • (9) Viability demonstration for nuclear vacuum-cooled power plants • (10) A large-scale Earthside vacuum-testing facility, costs, etc. Oh, I imagine that there are no end of people keenly interested in working on this enterprise. Hêll, I’d be in the induction office, were I in my 20s to 30s. It is definitely sexy, definitely hope-inspiring, definitely The Next Big Future (punfully

    Reply
  46. My fellow Goats… • Bulldozers• Giant smelting plants• Humungous algae farms• Megatons of off-Lunar material• Hundreds of gigawatts of power• Profoundly lethal failure modes• ZERO¹ hydrothermal concentration of ores• 32842 billion square meters … of unexplored surfaceWe found that there is no significant area of Luna which isn’t covered in an over-layer of meteoritically churned dusts; churned over billions of years smashed to flinders abrasive as hêll completely mixed down to the µm level. Remarkably mixed. Now while it is FUN (and who knows for people writing reports profitable!) to imagine being there digging stuff up carting it to the refining facility loading it in hoppers magnetically and using density electric fields pointiness”” and so on”””” separating the dusts into big old piles of separated “”””ore”””””” then taking said ores and somehow energy-efficiently refining and reducing these to metals gasses elements other compounds; stockpiling THESE and then re-blending and re-mixing them in novel (but not difficult or exotic) Lunar-oriented molecular programming processes … while that is all fun to imagine”” several things need first to be established:• (1) A real profit motivation• (2) Scope of economic investment before “”””break even””””• (3) The “”””sellable”””” pölïtical narrative to heavily tax the Nation.• (4) Buy-in by international community• (5) Buy-in by academic community• (6) Mandate for the new Space Force … in no uncertain terms• (7) Scope of supporting Earthside infrastructure”” costs”” personnel• (8) Legal basis for claiming “”””property”””” and IP rights• (9) Viability demonstration for nuclear vacuum-cooled power plants• (10) A large-scale Earthside vacuum-testing facility”” costs etc.Oh I imagine that there are no end of people keenly interested in working on this enterprise. Hêll I’d be in the induction office were I in my 20s to 30s. It is definitely sexy definitely hope-inspiring definitely The”

    Reply
  47. You get excess hydrogen because of the OXidizer part of methalox. You need to make enough of it to burn the methane. The burn equation is: CH4 (plus) 2 O2 –> CO2 (plus) 2 H2O If you write that into the synthesis equation and balance it out, you’ll see that you get more hydrogen from making the oxidizer than you need to make the methane: C (plus) 4 H2O –> CH4 (plus) 2 O2 (plus) 2 H2 The specific process doesn’t matter. What matters is the carbon source. With pure carbon as above, half the hydrogen goes into the methane, and half remains. With CO2 the remaining hydrogen reacts with the oxygen from the CO2 to get back water, so it cancels out (in this case, it’s exactly the reverse of the burn equation). With organic carbon such as from asteroids, there’s extra hydrogen in the carbon source, so you end up with even more hydrogen left over.

    Reply
  48. You get excess hydrogen because of the OXidizer part of methalox. You need to make enough of it to burn the methane. The burn equation is:CH4 (plus) 2 O2 –> CO2 (plus) 2 H2OIf you write that into the synthesis equation and balance it out you’ll see that you get more hydrogen from making the oxidizer than you need to make the methane:C (plus) 4 H2O –> CH4 (plus) 2 O2 (plus) 2 H2The specific process doesn’t matter. What matters is the carbon source. With pure carbon as above half the hydrogen goes into the methane and half remains. With CO2 the remaining hydrogen reacts with the oxygen from the CO2 to get back water so it cancels out (in this case it’s exactly the reverse of the burn equation). With organic carbon such as from asteroids there’s extra hydrogen in the carbon source so you end up with even more hydrogen left over.

    Reply
  49. There has been some interesting research on direct electrolytic reduction of mixed metallic oxides in molten salt electrolytes. Of course, for iron, you mostly just want to magnetically separate out the preexisting fraction of reduced iron from meteors, and then melt it to float out the contaminants.

    Reply
  50. There has been some interesting research on direct electrolytic reduction of mixed metallic oxides in molten salt electrolytes. Of course for iron you mostly just want to magnetically separate out the preexisting fraction of reduced iron from meteors and then melt it to float out the contaminants.

    Reply
  51. How are you getting excess hydrogen? The hydrogen from splitting water ends up in the methane (assuming Sabatier process).

    Reply
  52. Well, yes. Except for the fact that our choice of asteroids is — for pure conservation-of-energy reasons — limited to those which are in NEO “near Earth orbiting” orbits. The bits that are from ⅓ the way to Venus to ⅓ the way to Mars.

    Now this is not to say that there aren’t a bunch of NEOs that’d “work”.

    Your next problem, after figuring out which one to go to is kind of like the Luna problem. While not particularly expected to be composed of billion-year-churned-meteoritic dusts, what we’ve seen so far is that quite a few do look like barely-stuck-together-by-gravity lumps of smaller primordial material. Who knows. Big electromagnets might be able to reach in and pull out exactly what is needed. But I’m betting the really valuable stuff still requires refining.

    And here is where “asteroids” in NEO orbits are a bit of a pain in the derriere: just about no gravity.

    To put it straight, an asteroid (not terribly big, or small) at 2 km diameter, having a density of 1,250 kg/m³ will have a surface gravity of only 44.5 micro-G’s (0.0004365 m/s² or N/kg). If you or I were to so much as jump up from a squat (achieving over 1 m/s vertical velocity), quit literally, we would have reached the escape velocity of the rock. Off we’d go… floating away forever.

    The same problem goes for “mining”. Almost-zero gravity isn’t helpful in keeping things put. Equipment would need to dig (somehow!) and stick claws in the surface to hold on. Even then, being mostly composed of aggregated primordial dusts and boulders, it really isn’t clear how to mechanically “mine” the thing.

    Just saying.
    Moon is simpler.
    And closer.
    And friendly.

    GoatGuy

    Reply
  53. Not to be a stickler, but isn’t that just splitting more water than is stoichiometrically necessary and giving you excess? This can be done in a separate reactor under more ideal conditions to increase the efficiency of splitting water for the LOX.

    Reply
  54. My fellow Goats…

    • Bulldozers
    • Giant smelting plants
    • Humungous algae farms
    • Megatons of off-Lunar material
    • Hundreds of gigawatts of power
    • Profoundly lethal failure modes
    • ZERO¹ hydrothermal concentration of ores
    • 32,842 billion square meters … of unexplored surface

    We found that there is no significant area of Luna which isn’t covered in an over-layer of meteoritically churned dusts; churned over billions of years, smashed to flinders, abrasive as hêll, completely mixed down to the µm level. Remarkably mixed.

    Now while it is FUN (and who knows, for people writing reports, profitable!) to imagine being there, digging stuff up, carting it to the refining facility, loading it in hoppers, magnetically and using density, electric fields, “pointiness” and so on, separating the dusts into big old piles of separated “ore”, then taking said ores and somehow energy-efficiently refining and reducing these to metals, gasses, elements, other compounds; stockpiling THESE and then re-blending and re-mixing them in novel (but not difficult or exotic) Lunar-oriented molecular programming processes … while that is all fun to imagine, several things need first to be established:

    • (1) A real profit motivation
    • (2) Scope of economic investment before “break even”
    • (3) The “sellable” pölïtical narrative to heavily tax the Nation.
    • (4) Buy-in by international community
    • (5) Buy-in by academic community
    • (6) Mandate for the new Space Force … in no uncertain terms
    • (7) Scope of supporting Earthside infrastructure, costs, personnel
    • (8) Legal basis for claiming “property” and IP rights
    • (9) Viability demonstration for nuclear vacuum-cooled power plants
    • (10) A large-scale Earthside vacuum-testing facility, costs, etc.

    Oh, I imagine that there are no end of people keenly interested in working on this enterprise. Hêll, I’d be in the induction office, were I in my 20s to 30s. It is definitely sexy, definitely hope-inspiring, definitely The Next Big Future (punfully coöpting our Remarkable Leader’s website name).

    But people can’t just volunteer. This thing — done as imagined, and just from (1 to 10) above, as imaginable — this thing is going to be dâhmned expensive. Like trillions, and trillions, and trillions of “down payments on the future” expensive. Unfortunately, I see no way around this estimate. NOTHING that is lobbed into space, destined for Luna, on its way to mine regolith, is going to be cheap-and-easy to launch, to prove, to make work near-flawlessly Earthside.

    So, keep one’s financial, pölïtical and legal eyes wide open, Goats.

    GoatGuy
    _______

    ¹ Hydrothermal Ore Concentration — how we economically get our ores, here. Aeons of time is involved. Heated water dissolves ions; they precipitate out “downstream” when the water cools. It works. Just takes millions of years.

    Reply
  55. I’ve mentioned this before: If you use carbon and Lunar water to make methalox, you get an excess of hydrogen byproduct with most carbon sources. You can then use this hydrogen to reduce the Lunar oxides and recover a large fraction of the water (50% for pure carbon). You get metals (and partially reduced oxides) as a secondary product. This would reduce the smelting requirements. Lunar soil is ~7% aluminum (in oxide form), and there are ilmenite deposits, which is iron-titanium oxide. It could provide the metal for these bulldozers and for other stuff, but making bulldozers is complex, so they’ll probably be made on Earth for the foreseeable future. On Mars you’d be using CO2 as the carbon source for methalox, which wouldn’t leave any hydrogen excess. But it may still be easier to split some more water and then use the hydrogen to reduce the local oxides, than to reduce them directly.

    Reply
  56. I’ve mentioned this before:If you use carbon and Lunar water to make methalox you get an excess of hydrogen byproduct with most carbon sources. You can then use this hydrogen to reduce the Lunar oxides and recover a large fraction of the water (50{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} for pure carbon). You get metals (and partially reduced oxides) as a secondary product. This would reduce the smelting requirements.Lunar soil is ~7{22800fc54956079738b58e74e4dcd846757aa319aad70fcf90c97a58f3119a12} aluminum (in oxide form) and there are ilmenite deposits which is iron-titanium oxide. It could provide the metal for these bulldozers and for other stuff but making bulldozers is complex so they’ll probably be made on Earth for the foreseeable future.On Mars you’d be using CO2 as the carbon source for methalox which wouldn’t leave any hydrogen excess. But it may still be easier to split some more water and then use the hydrogen to reduce the local oxides than to reduce them directly.

    Reply
  57. You get excess hydrogen because of the OXidizer part of methalox. You need to make enough of it to burn the methane. The burn equation is:
    CH4 (plus) 2 O2 –> CO2 (plus) 2 H2O

    If you write that into the synthesis equation and balance it out, you’ll see that you get more hydrogen from making the oxidizer than you need to make the methane:
    C (plus) 4 H2O –> CH4 (plus) 2 O2 (plus) 2 H2

    The specific process doesn’t matter. What matters is the carbon source. With pure carbon as above, half the hydrogen goes into the methane, and half remains. With CO2 the remaining hydrogen reacts with the oxygen from the CO2 to get back water, so it cancels out (in this case, it’s exactly the reverse of the burn equation). With organic carbon such as from asteroids, there’s extra hydrogen in the carbon source, so you end up with even more hydrogen left over.

    Reply
  58. There has been some interesting research on direct electrolytic reduction of mixed metallic oxides in molten salt electrolytes. Of course, for iron, you mostly just want to magnetically separate out the preexisting fraction of reduced iron from meteors, and then melt it to float out the contaminants.

    Reply
  59. So did I understand correctly that the “shark fin” magnetic propulsion system would aim to use the higher density ion sheets that spiral out like a pinwheel around the sun? So in effect the sail would be ‘surfing ion waves’, and trips would be scheduled around the arrival of those waves, arriving I guess about every 12 days (half a solar rotation)?

    Reply
  60. So did I understand correctly that the shark fin”” magnetic propulsion system would aim to use the higher density ion sheets that spiral out like a pinwheel around the sun? So in effect the sail would be ‘surfing ion waves'”” and trips would be scheduled around the arrival of those waves”” arriving I guess about every 12 days (half a solar rotation)?”””

    Reply
  61. I’ve mentioned this before:
    If you use carbon and Lunar water to make methalox, you get an excess of hydrogen byproduct with most carbon sources. You can then use this hydrogen to reduce the Lunar oxides and recover a large fraction of the water (50% for pure carbon). You get metals (and partially reduced oxides) as a secondary product. This would reduce the smelting requirements.

    Lunar soil is ~7% aluminum (in oxide form), and there are ilmenite deposits, which is iron-titanium oxide. It could provide the metal for these bulldozers and for other stuff, but making bulldozers is complex, so they’ll probably be made on Earth for the foreseeable future.

    On Mars you’d be using CO2 as the carbon source for methalox, which wouldn’t leave any hydrogen excess. But it may still be easier to split some more water and then use the hydrogen to reduce the local oxides, than to reduce them directly.

    Reply
  62. So did I understand correctly that the “shark fin” magnetic propulsion system would aim to use the higher density ion sheets that spiral out like a pinwheel around the sun? So in effect the sail would be ‘surfing ion waves’, and trips would be scheduled around the arrival of those waves, arriving I guess about every 12 days (half a solar rotation)?

    Reply

Leave a Comment