Simultaneous thermal vacuum testing of GPS drives for NavStar

The solar array drive assemblies for the global positioning satellite (GPS) were built and the need to perform thermal vacuum acceptance testing on at least two complete units simultaneously is emphasized. The safety of the flight hardware is of primary importance. It is found that simultaneous space simulation testing of two complete drive packages requires only minor modification to the high vacuum pump stack. Attention is given to upgrading system safeties for high vacuum operation. Major modifications are designed and implemented for the thermal control system and supporting subsystems. The automated thermal control system and test bed hardware are of primary interest.