Optical properties of orbital debris

This paper discusses the albedos and phase angle effects found for 400 members of seven debris swarms using observations obtained in 1990 and 1991 with the NASA Johnson Space Center charge couple deviceequipped portable Schmidt telescope. The mean albedo derived by comparing optical brightnesses with averaged radar cross sections (RCSs) is 10%. The standard deviation in log albedo is 0.35 if the RCSs are assumed to contribute equally to the scatter. Forty objects are sufficiently free of tumble or aspect angle effects to yield consistent phase function slopes. These range from specular in nature (zero slope) through lambertian (moderate slope) to lunar (steep slope) with the mean lying midway between specular and lambertian. Swarm-to-swarm comparison shows the Cosmos 1375 debris to have unusually small scatter in albedo and the Spot I/Viking debris to have unusually bright albedos.