History of the development of radiation protection standards for space activities
Initial recommendations for limitations on radiation exposures in space were made in 1970 by the Radiobiological Advisory Panel of the Committee on Space Medicine, National Academy of Sciences/National Research Council (NAS/NRC). Using a risk-based approach and taking into consideration a range of factors, the Panel recommended an overall career limit of 4 Sv. Because it was assumed that only small numbers of people would be involved, most of whom would be in excess of 30 y of age, the question of genetic effects did not appear to be of concern. On the basis of subsequent epidemiological findings, the values of the risk coefficients were increased. As a result of this and other considerations, NASA in the early 1980s asked the NCRP to re-examine both the risks and the philosophy for protecting astronauts. In undertaking this task, the NCRP decided to treat the radiation exposures of crew members and payload specialists as an occupational hazard and to evaluate their risks in terms of those to radiation workers and to workers in other industries. Noting that in the less safe but not the most hazardous occupations, workers had an average lifetime risk of mortality of about three percent, the NCRP concluded that a reasonable career limit for astronauts should be based on a lifetime absolute excess risk of mortality of three percent. Using this as a base, the NCRP recommended a career limit for 25 y olds of 1 Sv for females and 1.5 Sv for males. Since the risk decreases the older the age at which the exposures begin, the limits culminated with a career limit of 3 Sv for females and 4 Sv for males whose initial exposure occurred at age 55. These recommendations were based on an assumed nominal value of a lifetime risk of fatal cancers for all ages of about 2 {times} 10{sup -2} Sv{sup -1}.
- Research Organization:
- National Council on Radiation Protection and Measurements, Bethesda, MD (United States)
- OSTI ID:
- 617743
- Report Number(s):
- CONF-960562-; ON: TI97006904; TRN: 98:006347
- Resource Relation:
- Conference: Symposium on acceptability of risk from radiation: application to manned space flight, Arlington, VA (United States), 29 May 1996; Other Information: PBD: 30 Apr 1997; Related Information: Is Part Of Acceptability of risk from radiation: Application to human space flight; PB: 195 p.
- Country of Publication:
- United States
- Language:
- English
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