Optimal mission abort policies for repairable multistate systems performing multi-attempt mission

Abstarct Research on mission abort strategies was mostly devoted to binary systems that can be only in two states, i.e., operable or failed. However, the real-world systems can often operate in intermediate states with different levels of performance. On the other hand, if a mission has been aborted and a system has been successfully rescued, at some instances, the next attempt can be activated, thus forming the multi-attempt framework. In this paper, the possibility of multiple attempts is considered for the first time for multistate systems. After each rescue, a system is repaired to ‘as good as new’ state. The repair time depends on its state before the repair. The objective is to maximize the probability of a mission completion within the fixed time deadline for systems operating in a random environment modeled by shocks. Each shock with a given probability results in a system's transition to the states with the lower values of performance. Mission abort is activated for each attempt when the number of experienced shocks exceeds a predetermined number. This number for each attempt should be determined to maximize the mission success probability. For the considered illustrative example, the detailed sensitivity analysis is performed and the relevant discussion is provided.