Fault protection architecture for the command and data subsystem on the Cassini spacecraft

Cassini is a NASA/JPL spacecraft that is planned to be launched in 1997 for a 10.7 year mission (6.7 in transit, 4 in orbit) to the planet Saturn. This paper focuses on one subsystem on the spacecraft, the Command and Data Subsystem (CDS). Overviews are presented of the Cassini and CDS avionics and then the internal fault protection architecture for the subsystem is described. This description covers fault detections, error filtering, event activation rules, and response triggering for the following key subsystem regions: (1) Command and Data Electronics Assemblies, (2) 1553B Bus and Remote Terminal Communication Interface Units, (3) Remote Engineering Units, and (4) Solid State Recorders.