lunar-Manufacturing-Notes

Manufacturing Notes
Dave Dietzler 2008

1) Q: How do you make screws for power line poles?
    A; Take cylinders of steel 20 cm (8 in.) in diameter and cut them on a large lathe. Then fit them             into the hollow poles and weld them in.

2) Q: How do you make big augers?
    A: Upport large fiberglass or plastic cores and make two halves of a mold from cement and
         sieved and sized regolith. Remove the cores and combine the two halves and fasten with
         bolts and/or metal bands. Pour steel in thru a hole in one of the halves. Let harden. May
         take several days. Separate halves and grind off flashing from the auger.

3) Q: How do you blacken titanium heat collection tubes for solar trough collectors?
    A: Not much carbon, so black basalt will be vapor deposited on tubes in the vacuum. Basalt is a           good insulator but the layer will be extremely thin.

4) Q: What will be the primary construction material in lava tubes?
    A: Probably concrete for walls, stairs, evening out floors, etc.

5) Q: How do you make magma electrolysis units on the Moon?
    A: Weld up a steel outer jacket. Fill bottom with insulating regolith. Lower in a slab of ceramic
         from upported magma units. Stack up "smart blocks" of ceramic and weld together with
         microwaves or electron beams to make inner walls. Fill up sides with regolith. Stack up fused
         silica bricks and "floor tiles" of fused silica to line inner walls and weld with microwaves or e-
         beams. Weld up titanium top cover and oxygen off gas pipe. Cut holes in steel outer jacket
         and use a heat probe to melt out holes for FeSi and ceramic outlet pipes that might be made
         of sintered titanium dioxide. Make titanium carbide electrodes from lunar titanium and carbon.

6) Q: Where do we get silica?
    A: We might be able to zone refine cast cylinders of volcanic glass or leach it with H2SO4 to                 purifiy it. Silica will be a byproduct of acid leaching during Al extraction and it will also be                  boiled out of anorthostic regolith during production of CaAl2O4.

7) Q: What about oxygen?
    A: Oxygen will come from magma electrolysis and ilmenite reduction. Possibly other metal                    extraction processes.

8) Q: What materials would you use for 1000 SPSs?
    A: Since steel has a higher strength to weight/mass ratio than aluminum esp unalloyed Al like               most of the Al we will produce on the Moon, it seems tube steel will be best for SPS frames.             This might require upporting carbon. But let's think this out. If we need say 20 million tons of            steel for 1000 SPS we need about 100,000 tons of carbon for 0.5% carbon steel. We'd have to        mine 1220 square km to a depth of a meter. If we launched it from Earth we'd need over 1,000       rocket launches. Either we need to mine a carbonaceous asteroid (s) or we must use aluminum       for the SPS frames.

Since magnesium production is just a matter of silicothermic reduction of MgO with FeSi and some CaO-Al2O4 flux in a solar furnace and we get the MgO by roasting regolith to get CaAl2O4 for steel cleaning while silicon production involves magma electrolysis, reaction with HCl to get silane and SiCl4, thermally decomposing them to get Si, zone refining the Si, doping the Si, making the solar panels with a steel or Al backing and a top electrode and a thin layer of glass, it looks like Mg is easier to produce. It's even easier to produce Al than silicon PVs. So we make foil or sheet Mg reflectors to concentrate sunlite on the silicon panels so we get more power out of less silicon. Or we could use Mg reflectors and titanium pipes with a thin layer of black basalt on them and trubogenerators. Finally, we use aluminum and/or calcium cables with a layer of Al deposited on them for wiring and cables.