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Space-based solar power (SBSP) is the concept of collecting solar power in space (using an "SPS", that is, a "solar-power satellite" or a "satellite power system") for use on Earth. It has been in research since the early 1970s.〔(【引用サイトリンク】title=Space-based solar power )〕〔(【引用サイトリンク】title=Space-Based Solar Power )〕 SBSP would differ from current solar collection methods in that the means used to collect energy would reside on an orbiting satellite instead of on Earth's surface. Some projected benefits of such a system are a higher collection rate and a longer collection period due to the lack of a diffusing atmosphere and night time in space. Part of the solar energy (55–60%) is lost on its way through the atmosphere by the effects of reflection and absorption. Space-based solar power systems convert sunlight to microwaves outside the atmosphere, avoiding these losses, and the downtime (and cosine losses, for fixed flat-plate collectors) due to the Earth's rotation. Besides the cost of implementing such a system, SBSP also introduces several new hurdles, primarily the problem of transmitting energy from orbit to Earth's surface for use. Since wires extending from Earth's surface to an orbiting satellite are neither practical nor feasible with current technology, SBSP designs generally include the use of some manner of wireless power transmission. The collecting satellite would convert solar energy into electrical energy on board, powering a microwave transmitter or laser emitter, and focus its beam toward a collector (rectenna) on Earth's surface. Radiation and micrometeoroid damage could also become concerns for SBSP. == History == In 1941, science fiction writer Isaac Asimov published the science fiction short story "Reason", in which a space station transmits energy collected from the Sun to various planets using microwave beams. The SBSP concept, originally known as satellite solar-power system (SSPS), was first described in November 1968. In 1973 Peter Glaser was granted U.S. patent number 3,781,647 for his method of transmitting power over long distances (e.g. from an SPS to Earth's surface) using microwaves from a very large antenna (up to one square kilometer) on the satellite to a much larger one, now known as a rectenna, on the ground.〔 Glaser then was a vice president at Arthur D. Little, Inc. NASA signed a contract with ADL to lead four other companies in a broader study in 1974. They found that, while the concept had several major problems – chiefly the expense of putting the required materials in orbit and the lack of experience on projects of this scale in space – it showed enough promise to merit further investigation and research.〔Glaser, P. E., Maynard, O. E., Mackovciak, J., and Ralph, E. L, Arthur D. Little, Inc., "Feasibility study of a satellite solar power station", NASA CR-2357, NTIS N74-17784, February 1974〕 Between 1978 and 1986, the Congress authorized the Department of Energy (DoE) and NASA to jointly investigate the concept. They organized the Satellite Power System Concept Development and Evaluation Program.〔(Satellite Power System Concept Development and Evaluation Program July 1977 - August 1980. DOE/ET-0034, February 1978. 62 pages )〕〔(Satellite Power System Concept Development and Evaluation Program Reference System Report. DOE/ER-0023, October 1978. 322 )〕 The study remains the most extensive performed to date (budget $50 million).〔(Statement of John C. Mankins ) U.S. House Subcommittee on Space and Aeronautics Committee on Science, Sep 7, 2000〕 Several reports were published investigating the engineering feasibility of such an engineering project. They include: * Resource Requirements (Critical Materials, Energy, and Land)〔(Satellite Power System (SPS) Resource Requirements (Critical Materials, Energy, and Land). HCP/R-4024-02, October 1978. )〕 * Financial/Management Scenarios〔(Satellite Power System (SPS) Financial/Management Scenarios. Prepared by J. Peter Vajk. HCP/R-4024-03, October 1978. 69 pages )〕〔(Satellite Power System (SPS) Financial/Management Scenarios. Prepared by Herbert E. Kierulff. HCP/R-4024-13, October 1978. 66 pages. )〕 * Public Acceptance〔(Satellite Power System (SPS) Public Acceptance. HCP/R-4024-04, October 1978. 85 pages. )〕 * State and Local Regulations as Applied to Satellite Power System Microwave Receiving Antenna Facilities〔(Satellite Power System (SPS) State and Local Regulations as Applied to Satellite Power System Microwave Receiving Antenna Facilities. HCP/R-4024-05, October 1978. 92 pages. )〕 * Student Participation〔(Satellite Power System (SPS) Student Participation. HCP/R-4024-06, October 1978. 97 pages. )〕 * Potential of Laser for SBSP Power Transmission〔(Potential of Laser for SPS Power Transmission. HCP/R-4024-07, October 1978. 112 pages. )〕 * International Agreements〔(Satellite Power System (SPS) International Agreements. Prepared by Carl Q. Christol. HCP-R-4024-08, October 1978. 283 pages. )〕〔(Satellite Power System (SPS) International Agreements. Prepared by Stephen Grove. HCP/R-4024-12, October 1978. 86 pages. )〕 * Centralization/Decentralization〔(Satellite Power System (SPS) Centralization/Decentralization. HCP/R-4024-09, October 1978. 67 pages. )〕 * Mapping of Exclusion Areas For Rectenna Sites〔(Satellite Power System (SPS) Mapping of Exclusion Areas For Rectenna Sites. HCP-R-4024-10, October 1978. 117 pages. )〕 * Economic and Demographic Issues Related to Deployment〔(Economic and Demographic Issues Related to Deployment of the Satellite Power System (SPS). ANL/EES-TM-23, October 1978. 71 pages. )〕 * Some Questions and Answers〔(Some Questions and Answers About the Satellite Power System (SPS). DOE/ER-0049/1, January 1980. 47 pages. )〕 * Meteorological Effects on Laser Beam Propagation and Direct Solar Pumped Lasers〔(Satellite Power Systems (SPS) Laser Studies: Meteorological Effects on Laser Beam Propagation and Direct Solar Pumped Lasers for the SPS. NASA Contractor Report 3347, November 1980. 143 pages. )〕 * Public Outreach Experiment〔(Satellite Power System (SPS) Public Outreach Experiment. DOE/ER-10041-T11, December 1980. 67 pages. )〕 * Power Transmission and Reception Technical Summary and Assessment〔http://www.nss.org/settlement/ssp/library/1981NASASPS-PowerTransmissionAndReception.pdf "Satellite Power System Concept Development and Evaluation Program: Power Transmission and Reception Technical Summary and Assessment" NASA Reference Publication 1076, July 1981. 281 pages.〕 * Space Transportation〔(Satellite Power System Concept Development and Evaluation Program: Space Transportation. NASA Technical Memorandum 58238, November 1981. 260 pages. )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Space-based solar power」の詳細全文を読む スポンサード リンク
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