title: LDEF radiation measurements:  preliminary results.
abstract: The Long Duration Exposure Facility (LDEF), retrieved by the Space Shuttle mission STS-32 after nearly 6 yr in orbit, is the focus of a broad-based study of the radiation environment in low Earth orbit (LEO) and its effects on materials.  A combination of passive techniques has been used to study this environment via detectors which were contained in experiments aboard the LDEF spacecraft and through analysis of induced radioactivities.  Preliminary results for absorbed dose measurements and for induced activities in various materials are presented.  A number of effects have been observed which reflect the anisotropy of the charged particle flux in low Earth orbit.  Quantitative results from these measurements should provide an accurate means of confirming environmental flux models and techniques for predicting radiation encountered in future LEO missions, particularly those of extended duration.
authors.affiliation: Universities Space Research Association, NASA Marshall Space Flight Center, Huntsville, AL 35812.
authors.forename: B A
authors.initials: BA
authors.lastname: Harmon
authors.forename: G J
authors.initials: GJ
authors.lastname: Fishman
authors.forename: T A
authors.initials: TA
authors.lastname: Parnell
authors.forename: E V
authors.initials: EV
authors.lastname: Benton
authors.forename: A L
authors.initials: AL
authors.lastname: Frank
mesh_terms: D000201:Activation Analysis; D003359:Cosmic Radiation; D004602:Elements; D018499:Linear Energy Transfer; D011834:Radiation Monitoring / Q000706:statistics & numerical data*; D011835:Radiation Protection / Q000706:statistics & numerical data*; D013026:Space Flight / Q000295:instrumentation*; D018531:Spacecraft; D013819:Thermoluminescent Dosimetry
chemical_list: D004602:Elements