EFFECTS OF 69 MONTHS IN LOW-EARTH-ORBIT ON KAPTON ANTENNA STRUCTURES

The overall objective of the long-duration exposure facility (LDEF) ex periment A0133, effects of the space environment on a space-based rada r phased-array antenna, was to evaluate components considered for an a ntenna concept. Of primary interest was degradation of the polyimide f ilm Kapton (DuPont trademark), the material considered for use in the antenna planes. The most striking result was the overall good conditio n of the Kapton antenna planes and tensile panels, despite nearly six years of exposure to the space environment. This was largely attributa ble to the orientation (parallel and hush on the space end) and the st ability of LDEF in orbit. However, weathering of exposed Kapton surfac es was not insignificant. Results on elongation and mechanical propert ies of the plain and the fiberglass-reinforced Kapton are presented. T he second objective was to investigate the interaction between high-vo ltage electrodes and typical spacecraft contaminants in simulation of discharge triggering across differentially charged dielectric surfaces (spacecraft charging conditions). Electronic data acquisition and mem ory systems appeared to operate correctly, but very few discharges wer e recorded. Induced radioactivity, contamination, impacts, and orienta tion features of atomic oxygen erosion were observed.