Long-Duration Exposure Facility

In general, the results from the LDEF spacecraft have provided much useful information on material sensitivity in the LEO environment. This is particularly true for selected materials such as thermal control coatings, composites, polymers, fasteners and solar cells. However, LDEF satellite material sensitivity data for other materials like glasses, glass coatings, lubricants, adhesives and seal materials were limited. Many of the experiments that flew on LDEF were only designed to measure material sensitivity for one year in an LEO environment. However, some materials expected to survive one year simply did not survive the 5.8 years that LDEF eventually remained in orbit. The initial inspections of the impact craters on LDEF surfaces revealed that there were no obvious physical differences in crater characteristic formed by natural meteoroids and those formed by man-made debris. The panel is one of four LDEF panels obtained by the SMC Heritage Center from the Aerospace Corporation. The attached magnifier reveals two of such impact craters. (USAF photo)