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Experiment Title: Effect of Space Environment on Space-Based Radar Phased-Array Antenna

Original Principal Investigator(s): Whiteside, Mr. James - Invest. Role: Original, Whiteside, Mr. James - Invest. Role: Present, DeIasi, Richard - Invest. Role: Original, Heuer, Ronald - Invest. Role: Original, Kesselman, Martin - Invest. Role: Original, Kuehne, Fredrick J. - Invest. Role: Original, Rossi, Martin - Invest. Role: Original,

Large space structures of low areal density are currently being developed for near-term applications such as space-based radar (SBR) and the Earth Observation System (EOS). The practical implementation of these structures depends largely on identifying low-cost, low-density, high-strength-to-weight materials that are not degraded by the low Earth orbit (LEO) and geosynchronous Earth orbit (GEO) environments. Because of the necessity for low weight and density, candidate materials include polymeric materials. Polymeric materials satisfy many of these requirements; however, the long-term stability of these materials exposed to the space environment is a major concern. The nature of the chemical bonds causes these materials to be susceptible to some degree of degradation from either ultraviolet or charged-particle (particularly high-energy electron) components of the space environment. In addition, for materials required to retain stiffness and dimensional stability, thermal excursions become an important factor because of creep at elevated temperatures. Atomic oxygen erosion is not a major concern in the SBR application environment, but it certainly becomes an issue at the lower altitudes flown by LDEF.

Based on the performance of numerous polymeric materials following accelerated laboratory testing, Kapton polyimide film was selected as the baseline material for the Grumman SBR concept. To gain the requisite confidence for long-term service durability, it was desirable to subject material specimens as well as a portion of the SBR antenna directly to the combined space environ- ment and compare property degradation to that caused by laboratory simulation.

Photograph Classification: Postflight

Associated Photograph(s):
LaRC - L92-21195
KSC - None
JSC - S32-S-288
LaRC - L90-10368
KSC - None
JSC - S32-75-062
LaRC - L89-04390
KSC - KSC-384C-255.09
JSC - None
LaRC - L91-15659
KSC - KSC-390C-1990.01
JSC - None

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