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Revised prediction of LDEF exposure to trapped protonsThe Long Duration Exposure Facility (LDEF) spacecraft flew in a 28.5 deg inclination circular orbit with an altitude in the range from 319.4 to 478.7 km. For this orbital altitude and inclination, two components contribute most of the penetrating charge particle radiation encountered - the galactic cosmic rays and the geomagnetically trapped Van Allen protons. Where shielding is less than 1.0 g/sq cm geomagnetically trapped electrons make a significant contribution. The 'Vette' models together with the associated magnetic field models and the solar conditions were used to obtain the trapped electron and proton omnidirectional fluences reported previously. Results for directional proton spectra using the MSFC anisotropy model for solar minimum and 463 km altitude (representative for the LDEF mission) were also reported. The directional trapped proton flux as a function of mission time is presented considering altitude and solar activity variation during the mission. These additional results represent an extension of previous calculations to provide a more definitive description of the LDEF trapped proton exposure.
Document ID
19930020444
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Watts, John W. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Armstrong, T. W. (Science Applications International Corp. Prospect, TN., United States)
Colborn, B. L. (Science Applications International Corp. Prospect, TN., United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1993
Publication Information
Publication: NASA. Langley Research Center, LDEF: 69 Months in Space. Part 1: Second Post-Retrieval Symposium
Subject Category
Atomic And Molecular Physics
Accession Number
93N29633
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19930020432Collected WorksLDEF: 69 Months in Space. Part 1: Second Post-Retrieval Symposium
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