SUMMARY SCOPE A reference Satellite Power System (SPS) has been designed by NASA and its contractors for the purposes of evaluating the concept and carrying out assessments of the various consequences of development, including those on the health of the space workers. The Department of Energy has responsibility for directing various assessments. Present planning calls for the SPS workers to move from Earth to a low earth orbit (LEO) at an altitude of 500 kilometers; to travel by a transfer ellipse (TE) trajectory to a geosynchronous orbit (GEO) at an altitude of 36,000 kilometers; and to remain in GEO orbit for about 90 percent of the total time aloft. This report deals with the radiation risks to the health of workers who will construct and maintain solar power satellites in the space environment. The charge to the committee was: a. To evaluate the radiation environment estimated for the Reference System which could represent a hazard; b. To assess the possible somatic and genetic radiation hazards; c. To estimate the risks to the health of SPS workers due to space radiation exposure, and to make recommendations based on these conclusions. ENVIRONMENT GEO has the highest ionizing radiation intensity. The Reference System proposes that most workers will spend most of their tour in space in this environment. The radiation environment in GEO is known only with sufficient accuracy to predict the radiation dose in free space to within a factor of two, and then only for objects in orbit for relatively extended periods for which average values of the radiation environment may be used. The short-term enhancement of the radiation belt intensity caused by geomagnetic substorms may result in significant deviations from the average doses and could increase the risk to health of exposed individuals caught outside shielded or protected areas. Solar particle events, which are rare events occurring most frequently in about eleven-year cycles, could increase the dose by a considerable factor. Shielding is the major factor which influences the dose and thus the potential health risk to the SPS worker. With the exception of the storm cellar, the shielding of the Reference System used in these estimates of dose is the minimum amount of material needed for the
RkJQdWJsaXNoZXIy MTU5NjU0Mg==