Attitude and articulation control for the Cassini spacecraft: a fault tolerance overview

This paper describes how fault tolerance has been addressed in the design of the Attitude and Articulation Control Subsystem for the Saturn-bound Cassini spacecraft. Cassini's fault tolerance objectives have strongly influenced the subsystem's level of autonomy, and have motivated some significant improvements over the autonomous capabilities of previous interplanetary spacecraft. Autonomous fault tolerant behaviors have been embedded at several points in the object-oriented flight control software, including a dedicated set of failure detection, isolation, and recovery algorithms.