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gamma radiation survey of the ldef spacecraftThe retrieval of the Long Duration Exposure Facility (LDEF) spacecraft after nearly 6 years in orbit offered a unique opportunity to study the long term buildup of induced radioactivity in the variety of materials on board. The first complete gamma ray survey was conducted of a large spacecraft on LDEF shortly after its return to Earth. A surprising observation was the large Be-7 activity which was seen primarily on the leading edge of the satellite, implying that it was picked up by LDEF in orbit. This is the first known evidence for accretion of a radioactive isotope onto an orbiting spacecraft. Other isotopes seen during the survey, the strongest being Na-22 and Mn-54, are all attributed to activation of spacecraft components in orbit. Be-7 is a spallation product of cosmic rays on nitrogen and oxygen in the upper atmosphere. However, the observed density is much greater than expected due to cosmic ray production in situ. This implies transport of Be-7 from much lower altitudes up to the LDEF orbit.
Document ID
19910015667
Document Type
Conference Paper
Authors
Phillips, G. W.
(Naval Research Lab. Washington, DC., United States)
King, S. E.
(Naval Research Lab. Washington, DC., United States)
August, R. A.
(Naval Research Lab. Washington, DC., United States)
Ritter, J. C.
(Naval Research Lab. Washington, DC., United States)
Cutchin, J. H.
(Sachs/Freeman Associates, Inc., Landover MD., United States)
Haskins, P. S.
(Florida Univ. Gainesville., United States)
Mckisson, J. E.
(Institute for Space Science and Technology, Inc., Gainesville FL., United States)
Ely, D. W.
(Institute for Space Science and Technology, Inc., Gainesville FL., United States)
Weisenberger, A. G.
(Institute for Space Science and Technology, Inc., Gainesville FL., United States)
Piercey, R. B.
(Mississippi State Univ. Mississippi State., United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1991
Publication Information
Publication: NASA, Langley Research Center, First LDEF Post-Retrieval Symposium Abstracts
Subject Category
ATOMIC AND MOLECULAR PHYSICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19910015658Analytic PrimaryFirst LDEF Post-Retrieval Symposium abstracts