Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

This report includes three experiment sections. The first experiment tested sensitivity to loss in altitude and demonstrated that: (1) preview effects led to adaptation; (2) sensitivity decreased with higher flow rates; and (3) sensitivity increased with higher optical texture densities and fractional loss. The second and third experiments…