Performability Evaluation of Fault-Tolerant Satellite Systems

A combined performance and reliability (performability) measure for gracefully degradable fault-tolerant satellite systems is introduced, and a closed-form analytic solution is provided in order to compute the performability for a class of unrepairable systems. An efficient algorithm for the solution of Markovian models which take into account the degradation of more than one type of system components is given. By means of an example on a commercial communication-satellite system we intend to illustrate this novel measure and compare it to more conventional ones.