they are at least readily accessible for testing, maintenance, and repair. In addition to the working parts, there are other areas to be examined, such as the environmental impact of the SPS. The proposed Heavy Lift Launch Vehicle would bum 20 million pounds of propellant enroute to LEO, and the electric ion engines intended for propulsion between LEO and GEO would release thousands of pounds of argon ions. The effects of these effluents on the atmosphere must be determined. Another major environmental issue concerns the impact of the powerful microwave beam on people, animals, and plant life, and on existing communications systems. Will radio astronomy have to move to the far side of the moon? Communication Satellite systems are the information and control lifelines for large segments of society — government, banking, commerce, transportation, industry, and defense. They must be maintained in operating condition. Recall that the electric power in the microwave beam of an SPS would exceed 5000 megawatts, almost 1% of the total electric generating capacity in the U.S. today. That amount of power must be handled very carefully or it could wreak unacceptable havoc on people, vital communications systems, and the environment. All of these uncertainties are in no sense a cause for panic or premature rejection of the feasibility of the SPS Program. They are, however, reasons for thorough analyses and thoughtful evaluation. Fortunately, the system and mechanisms for such analyses and evaluations are in place and at work. The DOE/NASA study is addressing not only every question that I’ve cited, but many others. In addition, the DOE has asked the National Academy of Science to convene a group of independent experts to examine the SPS question and specifically to scrutinize the DOE/NASA study to assure that no important issue has been overlooked. Neither the DOE/NASA study nor the NAS review is expected to reach a decision on whether the U.S. should proceed now to implement an SPS program. The objective is rather to determine whether the SPS concept offers sufficient promise to warrant a substantial five year program of exploratory development, tests, and additional in-depth analyses to enable a national decision to be made about 1986 on whether to proceed with implementation. This work should also identify the most sensitive assumptions and the development work required over a broad spectrum to move forward. Many issues go well beyond the technical questions of space operations and environmental impact, and it may be useful to consider briefly the overall scope and rationale for the SPS program. U.S. energy demand projections cover a wide range, depending on the assumptions used, but it seems clear that in the next 30 years total U.S. energy requirements will increase by at least 50%, even with effective conservation measures. It also seems clear that over the next thirty years our currently installed electric generating capacity of 600 Gigawatts will have to be more than doubled. In comparison to these numbers — 600 GW in 1980 and perhaps 1500 GW in 2010 — the capacity of a single 5 GW SPS is almost insignificant, and the 300 GW which could be provided by the proposed 60 unit SPS program would perhaps comprise only 20% of a 1500 GW requirement for 2010. My message here is that if the dimensions of the SPS program appear huge, so is the requirement it is intended to satisfy. U.S. energy requirements are so enormous that despite conservation there will be increasing demands for coal, for nuclear power, and for whatever hydropower, oil and natural gas can be acquired, even with the proposed 60 unit SPS program. There are other difficult issues, too. Some of them just as complex and even more perplexing. To begin at the beginning—who’s going to pay for, own, control, and use the
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