| Lunar Roads and Silicon Industry David Dietzler 2008 |
| Five hundred magma electrolysis units could produce enough silicon, about 15 million tons, in 30 years to build 1000 SPS. See: Silicon Production These would need 1500 MWe of power. This could come from amorphous silicon cells generating 100w/m^2. This would have an area of 15 million square meters or 3873 by 3873 meters. That's about 3.9 km by 3.9 km or 2.4 miles by 2.4 miles for those who are more familiar with english units. For those familiar with farms and ranches, that's 3690 acres. We would not build one big solar panel farm and have 500 MEUs (magma electrolysis units) in one big bank. There would be too much digging going on all around the installation to put it in one big complex. Solar panel farms with "stadium arrangement" might interfere with each other if they were too big. Also, iron and titanium rich basalt seems to exist in "splotches" in the Aitken Basin if we do the work there. We would spread the MEUs and solar panels about in the Aitken Basin and southern seas of the Moon. They would be built by various contractors instead of one giant vertically organized space corporation. The power sats would be built by various utility companies too instead of one huge international government entity or corp giant. Although some international government entity could get the ball rolling by doing R&D, developing the Ares rocket and maintaining research bases on the Moon where we experiment and get hard data and real world experience. The mine sites, MEUs and solar farms would be connected by cast basalt roads for smooth travel over the Moon instead of struggling thru dirt and leaving ruts. A grader or graders, a steam roller or steam rollers, not realy steam but electrically powered, would smooth out, remove rocks and compact the rutty dirt roads. They would follow the cables and towers of the southern lunar power grid consisting of numerous solar farms and cable lines and clamp onto the lines to recharge. There could also be recharging sub-stations every number of miles, so the line could be live at all times. Or they would have nuclear power with thermoelectrics and maybe a steam turbine using reactor or RTG waste heat for motive power. Nuclear steam power like a nuclear sub. Since reactor or RTGs can't be shut down we just have a clutch from the turbine to the wheels and a manually shifted gearbox. The actual stickshift would be outside and would be controlled by solenoids activated by the driver's joystick. Braking would be done by disk brakes with ceramic pads. See: Lunar Model T The compacted regolith would form a shallow wide channel that we pour molten basalt into. Perhaps we would have a mobile solar furnace and mining shovel that loads the mobile solar furnace with mare regolith. We might build the furnace out of lite wt titanium with a double wall and upported asbestos insulation with a silica lining. A huge aluminized Mylar umbrella would serve as the primary reflector and a fused titanium secondary reflector would not melt. As the solar furnace melts the mare basalt we'd just pour it out and let it harden. The roads would be double laned, that would mean two roads 8 ft wide perhaps with ten ft of space between them. Traffic would go in opposite directions. Alternatively, a powerful microwave robot could just melt the ground after grading and compactiong by grader and "steam" roller. There would be turn around slabs of basalt every now and then interconnecting the lanes. So we could build a road system for conveying solar panels, iron, O2 tanks, raw regolith, finished products, etc. in the Aitken Basin and southern maria. Upon reaching hilands the road might end or we could make it out of glassy hiland melted and hardened regolith. We would no longer use toothed wheels but perhaps wheels with solid Teflon tires that were sort of studded for traction. Or some kind of solid silicone rubber tires. Don't want to slide off the road. Where will all the roads lead to? The huge mass driver that shoots payloads to L2 or even all the way to L5. The mass driver will be Rome. We will need lots of power for it. Perhaps a nuclear plant would be best for 24/7 operaions. This would be far more feasible than a superconducting mag-lev RR, but that will eventually see its realization when lunar industry for Planet Moon grows large enough. Final points: Magma electrolysis will produce impure silicon. It will be necessary to react the crushed up and powdered silicon with hot HCl gas to form silane and silicon tetrachloride. The SiCl4 would be decomposed on hot metal fingers at 800-850 C. to get more pure silicon that would then be zone refined to 99.999% purity. The silicon would then be dopend with Al and P. Fluorine gas for silicon purification is not recommened. It is too corrosive. Titanium can withstand chloride but not fluoride corrosion. Titanium will compose the silicon purification apparatus. Fifteen million tons of silicon PVs for 1000 SPSs is a tall order, not just for mining and transportation by road and by mass driver into space, but for manufacturing. Regolith must be dug up, run thru magma electrolysis and a carbon nanotube filter to separate it from iron, the low grade or metallurgical grade silicon must then be reacted with HCl gas and then a resinous bed with AlCl3 catalyst to silane and SiCl4, both that will be decomposed with heat to get fairly pure silicon, though some silane will be used for rocket fuel, and the chlorine and hydrogen recycled. This silicon must then be zone refined and doped with Al and P and sprayed in two layers on a steel or aluminum back plate electrode. A front screen electrode must be applied and a thin layer of glass for anti-reflection coating. Things might be simplified and made cheaper if we can print purified and doped silicon as is done by Nanosolar, Inc. See. www.nanosolar.com Aluminum can be extracted in several ways. See: Lunar Aluminum Magnesium production might be as simple as magnetically and electrostatically concentrating magnesium olivines and pyroxenes and reducing them with FeSi from magma electrolysis in a flux of CaAl2O4 at 1200 C.+ The flux would be obtained by roasting anorthositic regolith in a solar furnace at over 1500 C. Anorthosite roasting will also yield MgO that can be reduced with silicon. Basalt roasting would yield more FeO and MgO but less CaAl2O4 since mare basalt is only 30% anorthite ( CaAl2Si2O8). Since magnesium production is simpler than Al and silicon PV production it would be wise to make large sheet or foil reflectors of Mg to concentrate solar energy on silicon PV panels and increase their output in order to reduce the burden of silicon and PV production. Maybe we will need only five million tons of silicon or less if we install magnesium reflector/concentrators on SPSs. We will still need to make millions of tons of magnesium but this is simpler, more straightforward and probably cheaper than making silicon PVs. See: Magma Process and Lunar Derived Propellant Rockets |
| Volcanic glass could serve as a source of chlorine and other elements. See: Lunar Volcanic Glass |
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| All roads lead to Rome, in this case a mighty mass driver in the center of the Aitken Basin. For more information see: Numbers and Mass Drivers |
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