INTELSAT-VI ON-BOARD SS-TDMA SUBSYSTEM DESIGN AND PERFORMANCE

The design and performance of the satellite-switched time-division multiple access (SS-TDMA) subsystem on board the INTELSAT VI Spacecraft is described. A brief overview of the subsystem hardware and capabilities is presented, followed by a discussion of the key design features of the microwave switch matrix (MSM), distribution control unit (DCU), and timing source for the subsystem, including their hardware implementations. The design of redundancy configurations for enhanced reliability, and for recovery from failures after fault identification, are then addressed. A 10-year probability of survival in excess of 0.99 has been designed by providing an input path redundancy of 10-for-6 for the MSM, 2-for-1 redundancy for the DCU, and 3-for-1 redundancy for the timing source. The philosophy guiding the extensive test program adopted for the SS-TDMA subsystem, from design conception through full-scale spacecraft integration, is also described.