Optimal mission abort policy with multiple shock number thresholds

At many instances, it is important to keep a system from being destroyed or “lost†at a cost of not completing its mission. Therefore, to enhance survivability of many real-world critical systems (e.g. aircrafts and human space flight systems), mission abort procedures are often utilized in practice. In this article, in order to suggest an optimal abort policy, we first develop a methodology for obtaining the mission success probability and survivability of system experiencing both internal failures and external shocks. Each shock increases degradation in a system, and therefore, the number of experienced shocks can be considered as a decision parameter. We divide the mission time into a number of adjacent intervals and suggest a policy when a mission is aborted (and a rescue procedure is activated) if the number of shocks exceeds the value predetermined for each interval. We demonstrate the trade-off between system survivability and mission success probability that should be balanced by the proper choice of the mission abort policy. An illustrative example of a mission performed by an unmanned aerial vehicle is presented.