NASA's long-range plans include possible human exploratory missions to the moon and Mars within the next quarter century. Such missions beyond low Earth orbit will expose crews to transient radiation from solar particle events as well as continuous high-energy galactic cosmic rays ranging from energetic protons with low mean linear energy transfer (LET) to nuclei with high atomic numbers, high energies, and high LET. Because the radiation levels in space are high and the missions long, adequate shielding is needed to ...
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NASA's long-range plans include possible human exploratory missions to the moon and Mars within the next quarter century. Such missions beyond low Earth orbit will expose crews to transient radiation from solar particle events as well as continuous high-energy galactic cosmic rays ranging from energetic protons with low mean linear energy transfer (LET) to nuclei with high atomic numbers, high energies, and high LET. Because the radiation levels in space are high and the missions long, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. The knowledge base needed to design shielding involves two sets of factors, each with quantitative uncertainty-the radiation spectra and doses present behind different types of shielding, and the effects of the doses on relevant biological systems. It is only prudent to design shielding that will protect the crew of spacecraft exposed to predicted high, but uncertain, levels of radiation and biological effects. Because of the uncertainties regarding the degree and type of radiation protection needed, a requirement for shielding to protect against large deleterious, but uncertain, biological effects may be imposed, which in turn could result in an unacceptable cost to a mission. It therefore is of interest to reduce these uncertainties in biological effects and shielding requirements for reasons of mission feasibility, safety, and cost.
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Seller's Description:
Good. The format is approximately 8.25 inches by 10.75 inches. xii, 75, [1] pages. Illustrated front cover. Some red ink marks noted. Figures. Tables. References. This is one of the National Academies Compass Series. Astronauts who venture beyond the protection of Earth's atmosphere and magnetosphere risk exposure to levels of radiation far exceeding those on Earth. Of all the risks, this one is probably the most straightforward to control-by providing adequate shielding. However, because shielding adds weight, cost, and complexity to space vehicles, it is very important for designers to have a good, quantitative understanding of the risk and its degree of certainty. This report assesses our understanding of radiation hazards in space. It also considers the additional research needed to reduce the areas of uncertainty, research that must be completed prior to undertaking the detailed design of a vehicle carrying crew members into space for periods of extended exposure. The report finds that it will take more than a decade of research to answer even the narrowest set of key questions. The nation has backed away from a specific timetable for human exploration of the moon and Mars. Yet it seems plausible that such expeditions will be mounted sometime in the first quarter of the 21st century, especially given the recent resurgence of interest in possible life on Mars from the study of meteorites. It becomes clear, when the lengthy time scale of the research is also taken into account, that the present report is indeed timely and should receive prompt consideration by NASA planners. NASA's long-range plans include possible human exploratory missions to the moon and Mars within the next quarter century. Such missions beyond low Earth orbit will expose crews to transient radiation from solar particle events as well as continuous high-energy galactic cosmic rays ranging from energetic protons with low mean linear energy transfer (LET) to nuclei with high atomic numbers, high energies, and high LET. Because the radiation levels in space are high and the missions long, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. The knowledge base needed to design shielding involves two sets of factors, each with quantitative uncertainty-the radiation spectra and doses present behind different types of shielding, and the effects of the doses on relevant biological systems. It is only prudent to design shielding that will protect the crew of spacecraft exposed to predicted high, but uncertain, levels of radiation and biological effects. Because of the uncertainties regarding the degree and type of radiation protection needed, a requirement for shielding to protect against large deleterious, but uncertain, biological effects may be imposed, which in turn could result in an unacceptable cost to a mission. It therefore is of interest to reduce these uncertainties in biological effects and shielding requirements for reasons of mission feasibility, safety, and cost.
