of the equipment and many, many times the value of the equipment. The product would be a powdered metal from which machine parts, nuts, bolts, etc., could be made with a compressor (ram lens). Dr. Jeremy D. Dunning of Indiana University presented a paper on “Electrophoretic Separation of Lunar Soils in a Space Manufacturing Facility” which he had prepared with Robert S. Snyder of NASA's Marshall Space Flight Center. He said that continuous free flow electrophoresis processing would be more effective on the Moon than conventional separation techniques (magnetic, electrostatic, flotation, sieving, ultrasonic, and crushing) on account of the very fine grain of the lunar soil (50-100 jum) and the low gravity. He said that experiments are being done at Marshall Space Flight Center with simulated lunar soil with a field strength of 4 V/cm. He said they had been obtaining 92% efficiencies in the laboratory. Professor Arnold delivered a “Progress Report on Experimental Program to Develop HF Acid Leach Process for Refining Lunar Soils,” on which he has been working with David Criswell and Robert Waldron. He said that the work is being supported by the Space Studies Institute and is just getting started. He said that the highlands which cover 85% of the Moon are rich in Al, Ca, Si, and O; that the mares are rich in Fe, Mg, Ti, Si, and O; and the Kreep in and near the western ocean are rich in K, Na, U, trace elements, Si, and O. Apollo 15, he said, has shown that materials from all three areas are accessible. There is the fascinating and very difficult problem of hydrogen and water. Professor Arnold said he had written the paper on the possibility of a frozen lake about the size of Lake Erie under the lunar poles. There is also a small amount of hydrogen available in the lunar soil which has been brought by the solar wind. Fluorine and chlorine are the hardest materials to get on the Moon but it may be possible to recycle fluoride used as a reagent. Eileen Galloway asked whether priority should be given to the Moon or the asteroids. Professor Arnold said he was an asteroid person, but that, for the present, priority should be given to the Moon because it is right there, although asteroids will be used eventually. For some asteroids, for instance, there is only good entering opportunity every ten years and, furthermore, we have lunar samples in laboratories on Earth now but no asteroid samples. Dr. Robert Waldron of Rockwell International spoke on “Electrorefining Process for Lunar Free Metal: Space and Terrestrial Applications and Implications.” He said that aluminum was hard to extract and that it took a great deal of energy, perhaps 10,000 J, to extract 1 g of iron in lunar soils which is only slightly less efficient as a conductor. The principal mass that would have to be carried up from Earth for setting up an electrorefining process would be water and chloride salts. John Oldson presented a paper prepared by himself and his colleagues, John Livingston, Karl Brown, and Richard Edelson, on a preliminary design for a 1000 ton per year lunar liquid oxygen plant for bootstrapping lunar operations. He said that liquid oxygen could be used for propulsion and that its extraction would be fairly easy to perform with lunar materials. David Criswell spoke on “Powder Metallurgy in Space Manufacturing,” a talk which included work on self-replicating machines on the lunar surface. He recommended several automatic machines for space systems and the nonterrestrial utilization of materials. He analyzed 220 terrestrial processing techniques, seeking answers to the question, “What tools can you make in space?” and has identified 42 techniques adapted to space environments. Some of these, he said, might have early applications.
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