Estimates of galactic cosmic ray shielding requirements during solar minimum

Technical Report · Thu Feb 01 00:00:00 EST 1990

OSTI ID:6867995

Townsend, L W; Nealy, J E; Wilson, J W; Simonsen, L C

Estimates of radiation risk from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different arbitrary constituents per layer. Calculated galactic cosmic ray fluxes, dose and dose equivalents behind various thicknesses of aluminum, water and liquid hydrogen shielding are presented for the solar minimum period. Estimates of risk to the skin and the blood-forming organs (BFO) are made using 0-cm and 5-cm depth dose/dose equivalent values, respectively, for water. These results indicate that at least 3.5 g/sq cm (3.5 cm) of water, or 6.5 g/sq cm (2.4 cm) of aluminum, or 1.0 g/sq cm (14 cm) of liquid hydrogen shielding is required to reduce the annual exposure below the currently recommended BFO limit of 0.5 Sv. Because of large uncertainties in fragmentation parameters and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as a factor of 2 or more. The effects of these potential exposure uncertainties or shield thickness requirements are analyzed.

• Research Organization: National Aeronautics and Space Administration, Hampton, VA (USA). Langley Research Center
• OSTI ID: 6867995
• Report Number(s): N-90-17535; NASA-TM-4167; L-16715; NAS-1.15:4167; TRN: 90-028068
• Country of Publication: United States
• Language: English

Related Subjects

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RADIATION DOSES
COSMIC RADIATION
SHIELDING
SPACE FLIGHT
RADIATION HAZARDS
ALUMINIUM
COMPUTERIZED SIMULATION
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