The following are highlights of the findings. A. TECHNOLOGY 1. The SPS Reference System, which assumed that the satellite would generate 5 million kilowatts of baseload power at the receiving antenna on Earth, demonstrated that the technology for transmitting power from space to Earth is amenable to evolutionary development and that the SPS concept appears technically possible. 2. Alternative technologies were identified which would increase the technical feasibility and economic viability of the SPS Reference System. For example, an advanced SPS concept with technology improvements identified 2'h years after the SPS Reference System was evolved, based on the use of magnetrons, multiband gap solar cells, multiple antennas and a concentrating receiving antenna, projects a capital cost reduction from $3000 to $1500/kW. B. ENVIRONMENT The potential environmental impacts include microwave and nonmicrowave health and ecological effects, atmospheric effects, and effects on communication systems (due to possible disturbance of the ionosphere or direct electromagnetic interference from the power beam). Most of these represent limited and definable risks for which mitigating steps can be identified to reduce them to acceptable levels, but there are some (e.g., low-level microwave biological effects and the long-term effects on space workers of galactic ionizing radiation) which will require more detailed, quantitative investigation before they can be evaluated satisfactorily. No effects were identified which are clearly irreducible and unacceptable. C. RESOURCES 1. There are suitable areas for receiving-antenna sites throughout the United States, but the design of the receiving antenna must be adaptable to meet specific topographic requirements. Furthermore, the acquisition of suitable land sites in regions such as the Northeast will be difficult. Offshore receiving antennas may be preferable to supply power-consuming centers near the seacoast. Secondary uses of land sites for agriculture or offshore sites for mariculture are of potential interest. 2. No insurmountable material problems are evident. Analyses of the materials requirements for the SPS indicate that the demand for tungsten and possibly gallium (one of the SPS Reference System design options) may create supply difficulties. The growth in manufacturing capacity is expected to be adequate for most SPS components, except the solar cell arrays. These arrays will require the creation of new industrial production capacity to meet the requirements of the SPS. 3. Net energy analyses indicate that the SPS energy ratio is very favorable compared with that of fossil and nuclear energy options if the fuel requirements of alternative energy technologies are included.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==