The first commercial communications satellite with gallium arsenide on germanium (GaAslGe) solar arrays was launched in January 1996. The spacecraft, named Measat, was built by Hughes Space and Communications Company. The solar cell assemblies consisted of large-area GaAslGe cells supplied by Spectrolab Inc. with infrared reflecting (IRR) coverglass supplied by Pilkington Space Technology. A comprehensive characterization program was performed on the GaAslGe solar cell assemblies used on the Measat array. This program served two functions: first to establish the database needed to accurately predict on-orbit performance under a variety of conditions; and second, to demonstrate the ability of the solar cell assemblies to withstand all mission environments while still providing the required power at end-of-life. Characterization testing included: measurement of electrical performance parameters as a function of radiation exposure, temperature and angle of incident light; reverse bias stability; optical and thermal properties; mechanical strength tests, panel fabrication, humidity and thermal cycling environmental tests. The results provided a complete database enabling the design of the Measat solar array, and demonstrated that the GaAslGe cells meet the spacecraft requirements at end-of life.