The thermal design of a high-power C-band phased array with integral solid-state amplifiers, and its integration into a three-axis-stabilized spacecraft, are discussed. A thermal design has been developed employing fixed-conductance heat pipes and an embedded heat pipe radiator panel. The design tradeoffs and problems encountered in removing 2,000 W from a 1-m-diameter array are described, and possible solutions are presented. The highly concentrated heat source associated with solid-state amplifiers has emphasized the importance of minimizing MMIC chip internal thermal resistance in terms of the overall thermal control subsystem weight. Thermal test verification issues and concerns with 1-g operation in integrated spacecraft testing are also addressed.