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D Glossary and Acronyms
Pages 111-118

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From page 111...
... : A safety principle, as well as a regulatory requirement, that emphasizes keeping doses of and exposure to radiation as low as possible using reasonable methods, and not treating dose limits as "tolerance values"; defined at NASA as limiting radiation exposure to a level that will result in an estimated risk below the limit of the 95 percent confidence level. albedo: secondary radiation produced by interactions of galactic cosmic rays and high-energy solar protons with matter in the atmosphere or on the surface alpha particle: An energetic charged nucleus consisting of two protons and two neutrons.
From page 112...
... cargo habitat: a crew habitat that the Lunar Lander carries for delivery to the Lunar Outpost as a key part of the "Outpost-first" strategy CHMO: chief health and medical officer chronic effects: long-term effects of exposure to radiation; includes cancer, cataracts, and nervous system damage CI: confidence interval CME: coronal mass ejection, an explosion of plasma released from the atmosphere (or corona) of the Sun CNS: central nervous system computerized anatomical male/female: a model of human geometry used to evaluate radiation doses at various points inside the body Constellation system: the complete ensemble of launch vehicles, flight vehicles, ground support, support services, and lunar and planetary surface systems associated with the Vision for Space Exploration
From page 113...
... The crew ascending back to lunar orbit in the ascent stage leaves the descent stage behind on the lunar surface. descent stage habitat: in the descent stage, a pressurized crew habitat in which the crew would live during sortie missions deterministic process: process whereby a given event will occur whenever its dose threshold is exceeded DNA: deoxyribonucleic acid DOD: Department of Defense DOE: Department of Energy dose: The average energy deposited by radiation per unit mass of material.
From page 114...
... These rays are made primarily of hydrogen and helium but contain traces of all the elements. GCR: galactic cosmic radiation GOES: Geostationary Operational Environmental Satellite HDPE: high-density polyethylene, defined as having a density greater than 0.94 g/cm 3 HEPAD: High Energy Proton and Alpha Detector HZE: high atomic number and energy HZETRN: a transport code developed specifically for high-charge, high-energy particles that is widely used for space radiation shielding and design calculations ISS: International Space Station kerma: Kinetic energy released in materials, the sum of the initial kinetic energies for all charged particles released by uncharged ionizing radiation in a small sample of material divided by the mass of the sample.
From page 115...
... NIH: National Institutes of Health NM: neutron monitor NOAA: National Oceanic and Atmospheric Administration Nowcasting: prediction of total doses and the future temporal evolution of the dose once a solar particle event has begun NRC: National Research Council NSF: National Science Foundation NSRL: NASA Space Radiation Laboratory Orion Crew Exploration Vehicle: The Constellation system vehicle that will carry passengers in low Earth orbit, or from low Earth orbit to the Moon or Mars, and then back to Earth. Often referred to as CEV; in this report referred to as the Orion crew module.
From page 116...
... of the Sun Space Radiation Analysis Group (SRAG) : the radiation protection body of NASA responsible for radiation monitoring, projecting exposures, and ensuring adherence to principles of ALARA spallation: A high-energy nuclear reaction in which a high-atomic-number target nucleus is struck by a highe ­ nergy, light particle (typically a proton)
From page 117...
... NRC: U.S. Nuclear Regulatory Commission USAF: United States Air Force Wind: a NASA spacecraft that observes the Sun and solar wind Z: atomic number, the number of protons in the nucleus of an atom


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