| Attempting to Define a Lunar Industrial Seed
By Dave Dietzler Make it on the Moon, from what? That’s the problem. How do we solve it by landing a minimal amount of equipment on the Moon? I don’t see how we are going to be able to do this without at least several hundred tons of “industrial seed” equipment. We also need more exploration of the Moon. NASA will do the exploring for us. Industry will follow once the ground truth on the ice has been determined and the area around Mt. Malapert has been explored more thoroughly. Even so, it will be decades before private industry tackles the Moon for helium 3 if fusion of this element is ever achieved commercially and solar power satellites are built. It’s probably more realistic to bet on nuclear fission and fossil fuels for energy during the remainder of this century and possibly deuterium-tritium fusion. The government will only pump so much money into a lunar research base and businessmen are not going to throw away hundreds of billions for nothing. The whole thing might just turn out to be craziness or as Sen. Proxmire said about solar power satellites “not one penny for this nutty fantasy.” Another thing is for certain, rockets will have to stop exploding 2% of the time if there is going to be lunar tourism also. The Delta 2 is our most reliable rocket and it has a 2% failure rate. The Saturn V had a 100% success rate but there were only a limited number of launches. Even so, the Saturn V was highly overbuilt and probably would have performed reliably for hundreds of missions in my humble opinion. Space travel is extremely dangerous and it will have to become as safe as air travel if large numbers of people are going to travel in space. This is another good reason to use robots for most work in space. Perhaps industry will develop big, dumb, cheap, kerosene and LOX powered heavy lift cargo rockets in the future that are more reliable than racy high performance hydrogen/oxygen rockets. The payloads to LEO might be lower but if the cost per launch is low enough this could be more economical than using rockets that stretch technology to its limits. Highly reliable space planes could be developed for transporting people to LEO. I have calculated that by using an Ares V rocket, electric drives from LEO to LLO, and MMH/N2O4 fueled one way landers we could get 310 tons of actual cargo and 150 tons of spent landers on the Moon with ten launches. The launches would cost a total of $10 billion using the Ares V and at least another $10 billion to $20 billion would be spent on the payloads of robots and machinery. Let’s baseline this as the lunar industrial seed mass. Let’s hope the soil has already been watered by more orbiters, robotic landers and a NASA research base so that we know more about the Moon, where to mine, and how to do basic metal extraction and manufacturing on the Moon. Here is a list of suggested cargos: Stretched lens array solar cells, 10 MWe 30 tons That should be enough to get started and allow for growth If we are basing at Mt. Malapert the Sun only sets for 5 days at a time about 5 times a year, so do we really need heavy power storage systems?? Just shut down the robots. Mounts and aiming mechanisms for the solar panels 5 tons estimated Mining robots one ton each. Since not all of them will be working at the same time and some will break down let’s make it ten of them. Also we will need miners for different tasks like iron fines mining, volatiles mining, and ice mining, so we’d have 3 for two jobs and four for another 10 tons Robots for doing assembly work at one ton each, ten of them 10 tons Mobile robots will mine regolith and load magnetic and electrostatic mineral separation units and smelting furnaces. Stationary robots will be mounted on ceramic blocks from magma electrolysis and cut slabs and plates of metal and cast basalt placed on ceramic block tables by mobile robots. Cutting will be done with lasers and plasma arc cutters as directed by computer programs to make frames, webs, stiffeners and many other things. A magma electrolysis unit that can make 100 tons of O2 per year 7 tons Uses 300 kWe Annual thru put 500 tons, also produces about 100 tons silicon, 70 tons iron and 200 tons ceramic blocks. See pgs. 39-41 Development of the Moon If serial electrolysis is possible we can get iron and silicon separately from the magma furnace. If not we have to look at engineering carbon nanotube atomic filters or a more conventional technology like a centrifugal separator to get the iron and silicon unmixed. Iron fines grinders, screens and magnetic separators 4 tons Robot cranes, three tons each, two of them 6 tons 3D electron beam manufacturing devices. I’m guessing a ton each and we could use three of them 3 tons A rolling mill 3 tons Electric furnaces for melting iron fines, carburizing the iron to steel, and fluxing the steel. One furnace to do it all might be designed. The steel might also be so clean we don’t need to flux it. If we do have to flux it we will need a vacuum furnace to decompose anorthositic highland regolith to calcium aluminate flux. Fortunately we only need about 10-15 kg of this flux per ton of steel, so this furnace would not be too large. Let’s just wing out a guess of five tons for the furnaces. 5 tons Ilemnite electrostatic separater 1 ton Fluidized bed ilmenite H2 reduction system 3 tons SUBTOTAL.......................................................... 87 tons Hey, we’re doing pretty good! Excuse my casual rather than professional style. Since the output from the ilmenite reduction system is particles of TiO2 with iron blebs on them we need a system for separating them. Acid leaching, flushing with CO gas to convert the iron blebs to gaseous carbonyls, perhaps grinding and magnetic separation but I am not so sure about that because the particles are really small and TiO2 is fairly hard stuff. Perhaps high temp roasting in the vacuum could simply boil off the iron blebs. So let’s make another wild guess. 3 tons Then we need FFC cells to reduce the TiO2 to titanium metal and CaCl2 flux. 5 tons We need molds for casting metals. Let’s be generous. 10 tons Gas and liquified gas storage tanks. The tanks on the landers will be kevlar wound thin walled aluminum. These are not suited for storing LOX as far as I know. We will need insulated steel or titanium tanks 10 tons Then we need pumps, piping and space radiators to liquefy the oxygen 5 tons Extruders for making pipes, rods, wires, fibers of glass or mineral wool. The extruder for making fibers doesn’t need to be very big. Someday we will need axel rods. We also need small rods to cut into screws. What we really need is pipes for all the gas, liquid and cooling systems we must build beyond those we launch up to the Moon. The extruders will use a motorized screw to push billets thru the die instead of hydraulics. How about……………………………….. 4 tons Screw cutting lathes 0.5 tons Other lathes for cutting threads on pipe for instance 0.5 tons Chemical vapor deposition systems like those by Galactic Mining to make all sorts of shapes about 1/16 to 1/8 inches thick 15 tons Welding lasers and power supplies 2 tons Electronic componets for future robots made on the Moon 4 tons Reels of insulated copper wire 2 tons Electrical parts 2 tons SUBTOTAL.............................................................................150 tons Hey, we are only half way there. Do the robots communicate directly with Earth? The lunar rover did. Or do we have omnidirectional antennas on the robots and a tall radio tower hooked up to a dish that communicates with Earth? If we go this way we will need perhaps 5 tons Infatable chambers for CVD work so we can recapture CO gas and heat treat steel and do water quenching and condense the water vapor from the air and reuse it. 20 tons. CNC machines 30 tons Laser machine tools 5 tons Spare parts 20 tons Electric furnaces for sintering and casting regolith. Since the nearest basalt to Mt. Malapert is hundreds of kilometers away we will have to cast anothositic regolith that will form a glassy material that melts at 1500 C. There might be iron rich material on the NE slope of Mt. Malapert. Magma electrolysis doesn’t work so good in iron poor anorthositic highland regolith so we better find some iron rich material near Mt. Malapert or we are out of luck as far as magma electrolyis goes. At least in the near term. Highland regolith is about 3% iron and mare regolith is about 14% iron. If you roast highland regolith to 1200 C. in the vacuum minerals decompose and FeO boils out. This has been done experimentally but with only grams of material. Most regolith processing experiments have been done only with small masses of material. Will they scale up? We don’t know. But consider Hall, the guy who figured out how to electrolyze aluminum. He worked in his basement shop and made all his own equipment and his first experiments only produced small lumps of aluminum. So lets hope laboratory scale experiments will work on an industrial scale on the Moon. If we roast highland soil and boil out FeO then mix it with some raw highland soil to bring the iron content up to 14% then our magma electrolysis could work. This will produce ceramic blocks that melt around 1500 C. as well as oxygen with impurities (sodium and potassium oxides probably and some sulfur dioxide and maybe some nasty H2S that will have to be scrubbed out), iron and silicon that contain chromium and manganese. So let’s just shoot for……………………. 10 tons Why so heavy? Electric furnaces including magma electrolysis and steel making furnaces will need some thick ceramic liners. Some fiberglass or mineral wool insulation shouldn’t be to massive. The outer retaining shell could be titanium. Then there’s the mass of the electrodes, heating elements, power cables, etc. Although current flowing thru molten basalt will keep it hot, heating elements are needed to keep the residue molten when the electrolyis current is shut down after almost all the iron and most of the silicon is extracted, and heating systems for the drain pipes are needed to prevent hardening of material and clogging of the pipes. Five tons would not be one big furnace but many small ones. These electric furnaces, like the robots and solar panels, will be important cargos. We need bricks or blocks to make more furnaces. Regolith can be used for insulation and bricks with a steel outer jacket made on the Moon can be used. Electrodes present a problem since there is no appreciable platinum on the Moon unless we find a crater loaded with the stuff. If you looked at electrodes I suggested about 20 Moon makeable ceramics that might be used for electrodes. One of them is bound to work in the magma electrolyis furnace. The furnace would have to be heated up until it reached the temp. that the ceramic becomes as decent conductor. As for heating elements in the regolith roasting furnaces we might ship up some copper tubing and oscillators to make induction furnaces. Thin wires of iron or titanium might offer enough resistance to get really hot, but how many watts can they dissipate? An alloy of iron, aluminum and chromium can reach 2350 C. So we need more than bricks. Binders for making steel casting sand. This is another area where research is demanded. Regolith is not green sand. How usable will it be for sand casting??? It would have to be seived and sized for sure. We would need a work chamber to recapture water vapor. This one reason I’d like to rely on extrusion, forging and 3D additive manufacturing more than casting. So who knows? Let’s throw a ton of binders up there. 1 ton Dies for a drop forge made on the Moon and dies for extruders 1 ton Electric motor winding machines, a ton of them 1 ton Sheet metal brakes 0.5 ton Power cables 3 tons Chemicals for processing regolith presents some challenges. There’s enuff sulfur, hydrogen and oxygen on the Moon to make sulfuric acid that would be used for one step in aluminum extraction by one process and it could be used to make plaster-CaSO4, that can be used for casting aluminum and magnesium in pressurized inflated work chambers. Chlorine and carbon ( I will get to carbon later) are also used in the Al process that uses H2SO4. Chlorine and carbon are also used in the Kroll process for Ti extraction but FFC cells seem like a simpler way. They still need Cl for CaCl2 flux or electrolyte…Chlorine is also used in silicon purification before zone refining. Fluorine can also be used to purify silicon, even get it straight from regolith in the form of SiF4 that is decomposed with heat to silicon, but flourine is really nasty stuff. Titanium has excellent chloride resistance so when all is said it looks like we need chlorine. We’d ship it up there in salt form, perhaps copper chloride instead of bulky tanks of liquid Cl and electrolyze the molten salts to get Cl gas and copper metal. But what if we can take silicon from magma electrolysis and purify it by vacuum distillation??? Then zone refine it to ultra high purity??? And how bad do we need titanium? Titanium dioxide if we can get it apart from the iron is good stuff. It’s a high temp ceramic that could be used for lining furnaces, furnace pipes, even heat shields. So let’s just throw a few tons of copper chloride up there 3 tons And an electrolysis cell 0.5 tons Microwave beaming systems to transmit power to mining robots 30 tons SUBTOTAL ....................................................................................280 tons So we have 30 tons to go. We will need diamond bearings for robots and other machines made on the Moon that can work in the abrasive dust environment. We will need silicone seals to protect the bearings and other machine parts and silicone gaskets. If there is ice in shadowed polar craters we will need devices to roast out the water, condense it, store it (lander tanks could store water, but what about freezing?), electrolysis cells to break it down to hydrogen and oxygen or Hydrosol’s solar thermal system, storage tanks for the oxygen and hydrogen, radiators and piping to liquefy the H2 and O2, pumps, etc. Oxygen is a “soft cryogen” and is not too hard to liquefy and store. LH2 has to be super cold and it takes 30% as much energy as a mass of hydrogen contains to liquefy it. It might be better to store hydrogen in hydride form. Then we need magnesium powder or FeTi alloy powder. It might be possible to store hydrogen in carbon nanotubes. Hydride storage is denser than liquid storage, but hydrides are heavier. However, hydrides don’t require heavily insulated tanks. Compressors are needed to drive the H2 into the metal powder and the H2 is released by heating the metallic hydride, but this requires less energy than liquification. Liquefying hydrogen would most likely require more equipment than hydride or carbon nanotube H2 storage systems. LH2 systems will also endure intense stress caused by contraction caused by super cold temps and they could crack or pipes could burst apart where they are joined. We have to wonder how these problems have been solved on Earth. Gaseous hydrogen and hydride storage will probably not demand technology as complex as that which goes into LH2 handling systems. But what if we want to use hydrogen for rocket fuel? We could convert it to silane that liquefies at minus 112 C. I calculated that a silane/LOX powered rocket will only use 60% as much hydrogen and a LH2/LOX powered rocket. However, to make silane we need metallurgical grade silicon, HCl, an AlCl3 catalyst on a resinous bed and a bunch of tubes and containers made of titanium probably because it resists Cl corrosion, pumps, heating coils, etc. Silane production also yeilds SiCl4 that can be decomposed with heat to get silicon pure enough to be zone refined and used for solar panels after doping, probably with Al since we don’t have boron and phosphorus. So let’s chalk up 0.5 tons for the diamond bearings, 0.5 tons for silicone seals and gaskets, 5 tons for water electrolysis cells including hydride storage. We have 24 tons to go. Sabatier reactors with H2O electrolysis cells and CH4 pryolysis systems could amass…………………………………………………………….. 5 tons Fuel cells for power and water…………………………………………………...4 tons Cement mixer and related equipment………………………………………… 5 tons Tool attachments for robots including carbide circular saws for cutting up lander tanks and struts…………………………………………………………………………. 2 tons Water tanks……………………………………………………………………….. 1 ton Lander tanks can also be used for water storage Ball mills to crush up silicon……………………………………………………… 4 tons Molybdenum heat probes that can melt holes in cast basalt and other bricks 0.5 tons Nickel metal hydride batteries…………………………………………………….2.5 tons TOTAL....................................................................................310 tons Now we also have 150 tons of landers to cannibalize. These will have kevlar wound thin walled aluminum tanks coated with an inch or two of polyurethane, aluminum or carbon composite frames; steel pipes, pumps and rocket motors. The robots will cut them up with saws, lasers or electron beams. The metals melted down in electric furnaces. The kevlar and polyurethane heated until it decomposes to carbon, hydrogen, oxygen and nitrogen. The carbon composites ground up to dust and used for making steel on the Moon. Since the carbon composites will contain epoxy we would roast the ground up materials to decompose the epoxy into its constituent elements. It doesn’t take a lot of carbon to make a lot of steel, and there should be plenty to get started on the Moon in 150 tons of landers. NOTE: Volatiles storage tanks for H2, H2O, He3, He4, N2, CO, CO2 and CH4 were ommitted in this first draft as well as separation systems consisting of membranes, compressors, pressure swing absorption, cryo cooling radiators and associated piping. Also necessary will be systems that decompose the CO, CO2 and CH4 to carbon, hydrogen and oxygen. * We must trim some of the mass from other payloads to fit this essential equipment in. We might want two magma electrolysis units instead of one or 14 tons of them. We might want several small rather than two large magma electro. units in case one cracks. Some payloads might seem excessive, like 0.5 tons for screw cutting lathes-that's 1000 pounds! One might ask,"Why such a massive machine?" Actually, 0.5 tons would consist of numerous screw cutting lathes in anticipation of future expansion of the base. * See Basic Chemistry for Moon Miners Reader's suggestions are welcomed. |
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