Failures of mission-critical systems may result in irretrievable economic losses and significant damages. Mission abort is an effective way to reduce the risk of casualties and enhance the system survivability. A core concern in real operation is how to balance the mission reliability and the system survivability via elaborate mission abort plans. This paper investigates the condition based mission abort policies for systems subject to two-stage degradation process with normal and defective stages. Dynamic mission abort decisions are considered based on the degradation level together with the duration in the defective stage. The degradation control limit and time threshold are both dependent on the duration in the normal stage. Mission reliability and system survivability are derived and the structural properties of the optimal abort thresholds minimizing the expected costs of mission failure and system failure are investigated. In addition, we also compare the optimal policy against several heuristic policies where mission reliability and system survivability are evaluated. Numerical studies are presented to validate the obtained results.

关键任务系统的故障可能会导致无法挽回的经济损失和重大损失。任务中止是降低人员伤亡风险和提高系统生存能力的有效方法。实际操作中的一个核心问题是如何通过精心设计的任务中止计划来平衡任务可靠性和系统生存能力。本文研究了基于条件的任务中止策略，适用于具有正常和缺陷阶段的两阶段退化过程的系统。动态任务中止决策是基于退化级别和缺陷阶段的持续时间来考虑的。退化控制极限和时间阈值都取决于正常阶段的持续时间。导出了任务可靠性和系统生存能力，并研究了使任务失败和系统失败的预期成本最小化的最佳中止阈值的结构特性。此外，我们还将最优策略与评估任务可靠性和系统生存能力的几种启发式策略进行了比较。提出了数值研究来验证所获得的结果。