Powersat can become economically attractive and competitive. We are continuing these cost studies and, when they are completed, will be most happy to submit the results to this Subcommittee. Our approach has been—and will continue to be—based on a common sense design-to-cost philosophy. We know that for the program to make economic sense it must provide power at a competitive cost at the time the system becomes operational. We have used as our design to cost target, bus bar power costs in a range of 20 to 30 mils/kwh in 1975 dollars. This cost target appears to be within the competitive range for coal and nuclear generated electrical costs in the first decade of the next century. We then tried to construct a power satellite concept which both would be within a reasonable extrapolation of current technology and would be capable of being designed, built and operated to produce power in this cost range. In addition we have estimated the energy payback time for such a concept—that is the time for the power satellite to generate the amount of energy required to build it, place it in orbit, and operate it over its lifetime of thirty to one hundred years. We find this time could be less than two years. With such attractive payback time, it appears that the power satellite could be an attractive non-depletable, non-polluting, power source of the future even if our present estimates are off by 100%—I don't believe they are. Powersat should eventually become an economically viable power source of the future. How? Fossil fuel is finite, power consumption steadily is growing and the cost of energy constantly is rising. The point at which our oil and coal reserves are entirely depleted may be a matter of argument, but the fact that they eventually will be depleted is not. At some point in the not-too-distant future the cost of these fuels will reach the cost of the development of a nondepletable new source. And the sooner we can develop a competitively priced alternative the more fossil fuel we will have remaining for crucial uses other than the generation of electricity. Again, I must emphasize that space-based solar energy never will be the entire energy answer. But we feel it definitely must be one of the options. Nuclear fission, and with it the breeder reactor, must be developed further. Fusion, though promising no near-term reward, should be pursued. Ground-based solar power should be on line long before we will be gazing at a string of power satellites twinkling in the night sky. What should we do? A logical beginning would be the undertaking of thorough, complete systems and economics analyses to set requirements and cost targets. The Space Shuttle also should be looked upon as a key to the development of power satellite technology. It not only can carry into space many power-related experiments but also would offer the opportunity to develop spacecraft operations to a point where quick turn-arounds and many flights approach routine. The Shuttle also will be able to carry into orbit the material needed for the fabrication of the Space Station currently under study by NASA. This station will do much in the development of the techniques needed for the fabrication of large structures in space. Among other efforts worth pursuing are: The development of space-based thermal and photovoltaic conversion technologies. Demonstration on Earth of the techniques needed for RF power transmission in space. Space-based RF transmission experiments from small spacecraft in geosynchronous orbit. Determination of the environmental impacts, particularly the effects of microwave transmission. Solar power appears to be an extremely clean form of power generation, but this must be proved. An orderly development of space transportation systems, not only for power satellites but for continued development of the many uses of space. These and other steps must be scheduled in phases which insure an aggressive but orderly development. Each must pave the way for the next. A major expenditure of funds on system development need not begin until technical and economic feasibility have been proved. This development scheme fits into an ongoing evolution. It began with an expendable space system phase which grew out of the military missile capability of World War II. It was dominated by Apollo and brought about the development of space-based communications and observation systems. We now are into a second phase, marked by the development of the Shuttle and orbital assembly capabilities.
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