The use of lunar-derived LOX is thus a high-leverage item because it frees space vehicles from the inefficient and costly exercise of shipping bulk propellants. The total mass shipped to the Moon will be reduced significantly. And for the remaining flights, instead of transporting large quantities of LOX to the Moon, more people, complex equipment, and scientific instruments can be shipped to provide additional capabilities at the lunar outpost. Many chemical processes have been identified through studies and workshops sponsored by NASA and others which can potentially extract oxygen from lunar rocks and soils. NASA, universities, and industries throughout the world are all trying to understand these processes more fully to pick the best ones for plant design. It is important to note that the necessary co-products of oxygen production from the metal oxides in the lunar regolith are metals, especially iron and silicon. Aluminum and titanium are harder to produce, but would be useful for eventual satellite construction. This directly ties the initial production of oxygen with materials of value for construction of large space structures in the future. Other Basic Processing Capabilities Perhaps as important as propellant production will be the use of the regolith for the manufacture of basic material. While it is true that much of the cargo arriving on the Moon will be extremely complex equipment, there is a real need for simple, basic infrastructure; such as roads, rocket blast protection, and structures for habitats, storage, and equipment repair. If brought from Earth, the mass required for these uses would be enormous. For example, just for protection from solar particle radiation, the mass that would have to be brought to the Moon represents several Space Shuttle launches. The cost of transporting the hundreds of metric tons needed to protect an early habitat from this dangerous radiation would surpass a billion dollars at today's launch costs. The general theme for all of the above is that the basic capabilities of mining, bulk material handling, and processing experience can be developed for production of material which is important for the initial customer, which is likely to be the first lunar outpost (a government or international agency.) These products will lower the cost of operating and expanding the base by providing a certain amount of self-sufficiency. The initial units for small production will themselves be small and thus have a short mass pay-back time. The lowered amount of mass that then must be shipped to the Moon will result in lower costs, but also enable the transport of larger units for the production of increasing amounts of products within the constraints of the existing flight rate and space transportation vehicle capabilities. In their 1986 report, the National Commission on Space recommended the formation of “A continuing program to test, optimize, and demonstrate chemical engineering methods for separating materials found in space into pure elements suitable as raw materials for propellants and for manufacturing.” This directive was based on lab results from preliminary tests of oxygen extraction using electrolytic and chemical processes. The Commission continued with the following recommendation: ...“Research to pioneer the use, in construction and manufacturing, of space materials that do not require chemical separation; for example, lunar glasses and metallic iron concentrated in the lunar fines.” The development of many of the technologies in each of these disciplines will be synergistic. As in any development program, time and effort will be necessary to bring these possibilities to fruition. We have decades of experience to call on from the chemical processing, mining, energy, metallurgical, and manufacturing industries, however. 9.4.2 Other Non-terrestrial Resources Long range, it might be reasonable to consider the use of asteroids to provide material for construction or propellant manufacture in space. The difficulties in developing a process to utilize a resource which has not yet been sampled and characterized are enormous, however. The logistics of obtaining and processing the material are also daunting. It is not likely that this will occur in the near future given the current space program plans. Nevertheless, missions to carry out initial reconnaissance, and perhaps sample return, of selected asteroids with desirable orbital parameters seems warranted from a scientific viewpoint. This has the feature of providing the knowledge on which to base future decisions concerning the use of asteroids for indigenous space resource utilization. Man-made material which is currently discarded in space is another source of resources in space. An example of this is the use of external tanks from the U.S. Space Shuttle or the core of the Russian Energia. These are a large source of refined aluminum, mostly, which is currently allowed to re-enter the atmosphere and bum up. Other material which is in orbit, but is
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