SECTION V SPACE RADIATION HAZARDS IN LEO AND GEO A. SPACE RADIATION ENVIRONMENT Space radiation hazards to personnel during SPS assembly, construction, operation, and maintenance in LEO and GEO include the protons and electrons of the trapped radiation belts, the solar flare radiation, and galactic cosmic rays. These radiations constitute the major biological hazards to crew members. A quantitative description of the radiation environment has been obtained from the published data through December 1976 of the National Space Science Data Center of NASA Goddard Space Flight Center (Ref. 5 and 6). Some typical maps for trapped protons for solar maximum and solar minimum are given in Figures 2 and 3 where the environmental data are expressed in protons/cm -day for various energies (in MeV) and for different altitudes (in nautical miles) for a given orbit inclination. To protect the space workers, shielding is needed to attenuate the trapped charged particles, and the corresponding derived radiobiological dose, to acceptable levels to meet mission dose criteria. This is a significant factor in the sizing of space compartments and other space vehicles proposed to be used for assembly and operation. A preliminary estimate has been made and is shown as parametric depth-dose data based on the integral spectral environmental data derived from References 5, 6, and 7. B. PARAMETRIC DEPTH DOSE DATA The preliminary analysis which generates the parametric radiation dose data (Ref. 8) is carried out by using the SHIELD radiation transport program (Ref. 9) using the integral spectral data as input. The statistical analysis of solar cosmic protons was obtained from Ref. 10. The preliminary analysis covers geomagnetically trapped protons and electrons, electron-Bremsstrahlung radiation, and solar and galactic cosmic protons in a 500-km 30-degree assembly orbit (LEO) and in the GEO. The radiation-dose data cover a 6-month mission during the solar
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