Dynamic mission abort policy for systems operating in a controllable environment with self-healing mechanism

Catastrophic failures of safety-critical systems could result in significant economic losses and damage. To improve the survival probability of safety-critical systems, self-healing mechanism is usually considered in the design stage and mission abort may be conducted if the failure risk becomes too high. We investigate the optimal mission abort policies for systems subject to a controllable shock process with self-healing mechanism. Minor failure and catastrophic failures are two competing failure modes of the system. Imperfect repair is carried out when a minor failure occurs and the external shock process is renewed after the imperfect repair. Mission abort decisions are considered based on the time in mission and the number of experienced minor failures. The optimal mission abort problem is formulated within the framework of stochastic dynamic programming to minimize the expected total cost of mission failure, system failure and imperfect repair. The structural properties of the optimal policy are investigated using the optimal stopping theory and a case study is presented to illustrate the obtained results.