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Solar Particle Event Exposures and Local Tissue Environments in Free Space and on Martian SurfaceSolar particle events (SPEs) are a concern to space missions outside Earth s geomagnetic field. The September 29, 1989 SPE is the largest ground-level event since February 23, 1956. It is an iron-rich event for which the spectra are well measured. Because ten times this event matches the ground level data of the February 1956 SPE, it is suggested that an event with ten-times the scaled spectra of the September 29, 1989 SPE be used as a worst case SPE for spacecraft design. For the worst case SPE, the input spectra were reconstructed using Nymmik's (1995) model for protons, the O and Fe ion spectra of Tylka et al. (1997) to evaluate the iron enhancement ratio, and the Solar Energetic Particle Baseline (SEPB) composition of McGuire et al. (1986) for the heavy ions. The necessary transport properties of the shielding materials and the astronaut s body tissues are evaluated using the HZETRN code. Three shield configurations (assumed to be aluminum) are considered: space suit taken as 0.3 g/sq cm, helmet/pressure vessel as 1 g/sq cm, and equipment room of 5 g/sq cm. A shelter is taken as 10 g/sq cm on the Martian surface. The effect of shielding due to the Martian atmosphere is included. The astronaut geometry is taken from the computerized anatomical man (CAM) model.
Document ID
20040086550
Acquisition Source
Langley Research Center
Document Type
Other
Authors
Kim, M. Y.
(College of William and Mary VA, United States)
Shinn, J. L.
(NASA Langley Research Center Hampton, VA, United States)
Singleterry, R. C.
(NASA Langley Research Center Hampton, VA, United States)
Atwell, W.
(Boeing North American, Inc. United States)
Wilson, J. W.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 1999
Subject Category
Space Radiation
Distribution Limits
Public
Copyright
Public Use Permitted.
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