A failure tolerant power subsystem for outer planet spacecraft

Spacecraft electrical power subsystems require continuous monitoring, ground supported analysis of performance, and ground intervention to provide power management and fault correction. An interplanetary fly-by mission to the outer planets necessitates long periods of relatively low activity between encounters. It would be desirable to minimize ground access and support during these times if it can be shown that power management and fault removal functions can be implemented economically and reliably within the power subsystem flight equipment. This paper describes the interim results of a study to develop the techniques and implementation methods to provide a power subsystem capable of autonomous fault correction and power management. Each subsystem element is analyzed to define failure modes and failure characteristics which permit identification of fault correction methods. Fault protection concepts for each classification of loads are formulated to provide a high probability of delivering power to the load yet protect the power subsystem in the event of a load fault. The Mariner Jupiter/Saturn power subsystem elements formed the baseline for this study.