The triple calibration sphere (CALSPHERE) experiment

Three small [26-cm diameter) spheres were launched on February 15, 1971, into near circular 800-km high orbits with an inclination of 99° from the Western Test Range. Two of the spheres have a polished aluminum finish, the third is gold plated. Each has a mass of 732g. The different surfaces are used as a test of Cook's theory [1], [2].