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Radiation Protection Effectiveness of Polymeric Based Shielding Materials at Low Earth OrbitCorrelations of limited ionizing radiation measurements onboard the Space Transportation System (STS; shuttle) and the International Space Station (ISS) with numerical simulations of charged particle transport through spacecraft structure have indicated that usage of hydrogen rich polymeric materials improves the radiation shielding performance of space structures as compared to the traditionally used aluminum alloys. We discuss herein the radiation shielding correlations between measurements on board STS-81 (Atlantis, 1997) using four polyethylene (PE) spheres of varying radii, and STS-89 (Endeavour, 1998) using aluminum alloy spheres; with numerical simulations of charged particle transport using the Langley Research Center (LaRC)-developed High charge (Z) and Energy TRaNsport (HZETRN) algorithm. In the simulations, the Galactic Cosmic Ray (GCR) component of the ionizing radiation environment at Low Earth Orbit (LEO) covering ions in the 1< or equals Z< or equals 28 range is represented by O'Neill's (2004) model. To compute the transmission coefficient for GCR ions at LEO, O'Neill's model is coupled with the angular dependent LaRC cutoff model. The trapped protons/electrons component of LEO environment is represented by a LaRC-developed time dependent procedure which couples the AP8min/AP8max, Deep River Neutron Monitor (DRNM) and F10.7 solar radio frequency measurements. The albedo neutron environment resulting from interaction of GCR ions with upper atmosphere is modeled through extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. With the validity of numerical simulations through correlation with PE and aluminum spheres measurements established, we further present results from the expansion of the simulations through the selection of high hydrogen content commercially available polymeric constituents such as PE foam core and Spectra fiber(Registered TradeMark) composite face sheet to assess their radiation shield properties as compared to generic PE.
Document ID
20090026971
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Badavi, Francis F.
(NASA Langley Research Center Hampton, VA, United States)
Stewart-Sloan, Charlotte R.
(Stanford Univ. Stanford, CA, United States)
Wilson, John W.
(NASA Langley Research Center Hampton, VA, United States)
Adams, Daniel O.
(Utah Univ. Salt Lake City, UT, United States)
Date Acquired
August 24, 2013
Publication Date
May 18, 2008
Subject Category
Space Radiation
Report/Patent Number
LF99-5666
Meeting Information
Meeting: SAMPE ''08 Material and Process Innovations: Changing our World
Location: California
Country: United States
Start Date: May 18, 2008
End Date: May 22, 2008
Sponsors: Society for the Advancement of Materials and Process Engineering
Funding Number(s)
WBS: WBS: 732759.07.09
Distribution Limits
Public
Copyright
Other

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