The accepted usefulness of detailed stray light analyses and BRDF data, has grown steadily and significantly since
1980. Today the usefulness of these analyses is clearly understood in most areas of the optical space research community.
The Bidirectional Reflectance Distribution Function (BRDF), which defmes the scatter characteristics of surfaces, is a
term familiar enough to the community that an ASTM standard is in the fmal stages of approval. The published literature
now has significant amounts of BRDF data on an assortment of useful materials. Important space based systems have
been analyzed for stray light, and then measured in operation. The conelation between the measured and analysis results
has been very good. The software tools are more numerous, and they have more capability. There is much more theory
documented in the literature. Some of the theory is still being argued about, to different degrees of disagreement, but
the basic concepts are well established. Probably one of the most significant advances has been a series of contracts out
of Rome Air Development Center (RADC) on the Detection, Removal, and Prevention of Contamination. These works
hold great promise for the future.