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Tytuł:
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CRaTER observations and permissible mission duration for human operations in deep space.
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Autorzy:
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de Wet WC; University of New Hampshire Earth, Oceans, and Space Science Center, 8 College Road, Durham, NH 03824, United States. Electronic address: .
Slaba TC; NASA Langley Research Center, 1 Nasa Drive, Hampton, VA 23681, United States.
Rahmanifard F; University of New Hampshire Earth, Oceans, and Space Science Center, 8 College Road, Durham, NH 03824, United States.
Wilson JK; University of New Hampshire Earth, Oceans, and Space Science Center, 8 College Road, Durham, NH 03824, United States.
Jordan AP; University of New Hampshire Earth, Oceans, and Space Science Center, 8 College Road, Durham, NH 03824, United States.
Townsend LW; University of Tennessee Department of Nuclear Engineering, 1412 Circle Drive, Knoxville, TN 37916, United States.
Schwadron NA; University of New Hampshire Earth, Oceans, and Space Science Center, 8 College Road, Durham, NH 03824, United States.
Spence HE; University of New Hampshire Earth, Oceans, and Space Science Center, 8 College Road, Durham, NH 03824, United States.
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Źródło:
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Life sciences in space research [Life Sci Space Res (Amst)] 2020 Aug; Vol. 26, pp. 149-162. Date of Electronic Publication: 2020 May 25.
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Typ publikacji:
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Journal Article
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Język:
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English
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Imprint Name(s):
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Original Publication: Amsterdam : Elsevier Ltd, [2014]-
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MeSH Terms:
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Cosmic Radiation*/adverse effects
Radiation Dosage*
Radiation Protection*
Solar Activity*
Astronauts/*statistics & numerical data
Space Flight/*statistics & numerical data
Telescopes
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Contributed Indexing:
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Keywords: Cosmic ray telescope for the effects of radiation; Lunar reconnaissance orbiter; Permissible mission duration; Radiation risk; Solar cycle
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Entry Date(s):
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Date Created: 20200729 Date Completed: 20210226 Latest Revision: 20210226
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Update Code:
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20240104
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DOI:
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10.1016/j.lssr.2020.04.004
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PMID:
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32718681
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Prolonged exposure to the galactic cosmic ray (GCR) environment is a potentially limiting factor for manned missions in deep space. Evaluating the risk associated with the expected GCR environment is an essential step in planning a deep space mission. This requires an understanding of how the local interstellar spectrum is modulated by the heliospheric magnetic field (HMF) and how observed solar activity is manifested in the HMF over time. While current GCR models agree reasonably well with measured observations of GCR flux on the first matter, they must rely on imperfect or loose correlations to describe the latter. It is more accurate to use dose rates directly measured by instruments in deep space to quantify the GCR condition for a given period of time. In this work, dose rates observed by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument are used to obtain the local GCR intensity and composition as a function of time. A response function is constructed that relates observed dose rates to solar modulation potential using a series of Monte Carlo radiation transport calculations. The record of observed solar modulation potential vs. time is then used to calculate a recent historical record of permissible mission duration (PMD) according to NASA's permissible exposure limits (PEL). Tables are provided for extreme values of PMD. Additional tables include risk of exposure-induced death (at upper 95% confidence interval) accrual rates and NASA effective dose rates as a function of solar modulation potential, astronaut age, sex, and shielding thickness. The significance of the PMD values reported in relation to likely transit duration requirements for future exploration missions is discussed. There is general agreement between CRaTER observations and the prescription of solar modulation vs. time given by the Badhwar-O'Neill 2014 GCR model. However, CRaTER observations do capture the effects of significant heliospheric transients, among other features, that are missing from the prescription of solar modulation potential vs. time.
Competing Interests: Declaration of Competing Interest None.
(Copyright © 2020 The Committee on Space Research (COSPAR). All rights reserved.)
