Electrical power subsystem for the initial defense communications satellite program/augmentat ion (IDCSP/A)

The IDCSP/A satellites are communication satellites built by Philco-Ford Corporation under contract to the United States Air Force for United Kingdom applications, tailored for compatibility with the near synchronous IDCSP communication satellite network. These satellites utilize a mechanically despun antenna system and a hydrazine reaction control system for attitude control and station keeping. The design of these satellites utilizes advanced concepts reflecting current state-of-the-art. Design, integration, and test concepts of the IDCSP/A electrical power subsystem is discussed in this paper. This subsystem utilizes solar cells for primary power conversion and hermetically sealed nickel-cadmium batteries for enery storage. The power subsystem used in the IDCSP/A satellites has been designed to provide continuously regulated primary power to each satellite subsystem. This fully automatic power subsystem has been optimized to take full advantage of earth synchronous equatorial orbit characteristics. Flight data from the satellites demonstrates that the power subsystem is meeting or exceeding performance requirements.