Forty Years of Development of Active Systems for Radiation Protection of Spacecraft
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Forty Years of Development of Active Systems for Radiation Protection of Spacecraft J. Christopher Sussingham,' Seth A. Watkins,2 and F. Hadley Cocks? Abstract A comprehensive survey of the literature relating to active spacecraft shielding is presented, including electrostatic and plasma as well as magnetic methods. A literature discussion is provided in order to give an overview of this field. The advent of high temperature superconductors may make magnetic shielding against charged particle radiation practical in spacecraft engineering.
Introduction Solar flares are unpredictable events which cause high levels of charged particle radiation that can affect both manned and unmanned space missions. The Earth's magnetosphere allows a percentage of this radiation to reach the northern and southern magnetic polar regions. The aurora borealis and aurora australis are produced as energetic solar particle radiation collides with the upper atmosphere, and the resulting aesthetic display is a visual reminder that charged particle radiation is a hazard for satellites and manned spacecraft. In preparation for the Apollo lunar missions, the possibility of using active magnetic shielding to provide protection against the energetic solar particle radiation produced by solar flares was extensively evaluated but was never attempted. No active shielding was used on any of the Apollo missions because they were not conducted during periods of high energetic solar particle radiation activity [1]. The periodic loss of satellite systems as a result of energetic solar particle radiation, and as a result of upper atmosphere nuclear detonations, however, has led to a long series of papers related to potential shielding modalities, including active shielding. This present paper presents a comprehensive listing of more than 40 years of literature focusing on active radiation protection for spacecraft, especially protection from energetic solar particle radiation. To provide a background for the discussion of this literature, a brief historical perspective is useful. lUnited States Air Force, Ogden Air Logistic Center, Hill AFB, Utah 84056. University, Department of Mechanical Engineering and Materials Science, Durham, North Carolina, 27708-0300. 2Duke
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Historical Perspective The orbiting of Explorer I on January 31, 1958, was a milestone achievement. In addition to being the first satellite launched successfully by the United States, this satellite carried James Van Allen's experimental payload that identified the radiation belt that now bears his name. That same year, shortly after the discovery of this radiation hazard, the need for radiation shielding was recognized [2]. At that early time in the space program, manned missions were several years away and the primary issue was the deleterious effects of radiation on satellite electronics. Van Allen's cosmic ray detector, a Geiger-Mueller tube, had been saturated by the incident radiation, thus demonstrating that space-borne electronics and sensor
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