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11.
John H. Heinbockel Tony C. Slaba Steve R. Blattnig Ram K. Tripathi Lawrence W. Townsend Thomas Handler Tony A. Gabriel Lawrence S. Pinsky Brandon Reddell Martha S. Clowdsley Robert C. Singleterry John W. Norbury Francis F. Badavi Sukesh K. Aghara 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The protection of astronauts and instrumentation from galactic cosmic rays and solar particle events is one of the primary constraints associated with mission planning in low earth orbit or deep space. To help satisfy this constraint, several computational tools have been developed to analyze the effectiveness of various shielding materials and structures exposed to space radiation. These tools are now being carefully scrutinized through a systematic effort of verification, validation, and uncertainty quantification. In this benchmark study, the deterministic transport code HZETRN is compared to the Monte Carlo transport codes HETC-HEDS and FLUKA for a 30 g/cm2 water target protected by a 20 g/cm2 aluminum shield exposed to a parameterization of the February 1956 solar particle event. Neutron and proton fluences as well as dose and dose equivalent are compared at various depths in the water target. The regions of agreement and disagreement between the three codes are quantified and discussed, and recommendations for future work are given. 相似文献
12.
Ehlmann BL Chowdhury J Marzullo TC Collins RE Litzenberger J Ibsen S Krauser WR DeKock B Hannon M Kinnevan J Shepard R Grant FD 《Acta Astronautica》2005,56(9-12):851-858
Mars is a compelling astrobiological target, and a human mission would provide an opportunity to collect immense amounts of scientific data. Exploration alone, however, cannot justify the increased risk. Instead, three factors drive a human mission: economics, education, and exploration. A human mission has a unique potential to inspire the next generation of young people to enter critically needed science and engineering disciplines. A mission is economically feasible, and the research and development program put in place for a human mission would propel growth in related high-technology industries. The main hurdles are human physiological responses to 1–2 years of radiation and microgravity exposure. However, enabling technologies are sufficiently mature in these areas that they can be developed within a few decade timescale. Hence, the decision of whether or not to undertake a human mission to Mars is a political decision, and thus, educational and economic benefits are the crucial factors. 相似文献