DocumentCode :
1253207
Title :
Solar modulation of dose rate onboard the Mir station
Author :
Badhwar, G.D. ; Shurshakov, V.A. ; Tstelin, V.V.
Author_Institution :
NASA Johnson Space Center, Houston, TX, USA
Volume :
44
Issue :
6
fYear :
1997
fDate :
12/1/1997 12:00:00 AM
Firstpage :
2529
Lastpage :
2541
Abstract :
Models of the radiation belts that are currently used to estimate exposure for astronauts describe the environment at times of either solar minimum or solar maximum. Static models, constructed using data acquired prior to 1970 during a solar cycle with relatively low solar radio flux, have flux uncertainties of a factor of two to five and dose-rate uncertainties of a factor of about two. The inability of these static models to provide a dynamic description of the radiation belt environment limits our ability to predict radiation exposures for long-duration missions in low earth orbits. In an attempt to add some predictive capability of these models, we studied the measured daily absorbed dose rate on the Mir orbital station over roughly the complete 22nd solar cycle that saw some of the highest solar flux values in the last 40 y. We show that the daily trapped particle dose rate is an approximate power law function of daily atmospheric density. Atmospheric density values are in turn obtained from standard correlation with observed solar radio noise flux. This correlation improves, particularly during periods of high solar activity, if the density at roughly 400 days earlier time is used. This study suggests the possibility of a dose- and flux-predictive trapped-belt model based on atmospheric density
Keywords :
cosmic ray solar modulation; dosimetry; radiation belts; radiation protection; solar activity; solar cosmic ray particles; space research; Mir station; astronauts; dose rate; dynamic description; flux uncertainties; high solar activity; long-duration missions; low earth orbits; radiation belts; radiation exposures; solar flux values; solar modulation; trapped-belt model; Accuracy; Belts; Biomedical measurements; Electron traps; Extraterrestrial measurements; Low earth orbit satellites; Predictive models; Protons; Space shuttles; Uncertainty;
fLanguage :
English
Journal_Title :
Nuclear Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9499
Type :
jour
DOI :
10.1109/23.650860
Filename :
650860
Link To Document :
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