Gamma process based optimal mission abort policy

•Developing degradation-based and duration-based mission abort policies based on a two-stage degradation process.•Deriving mission reliability and system survivability under the proposed stochastic failure process and mission abort policies.•Investigating the optimal mission abort policies balancing the tradeoff between mission reliability and system survivability.•Providing a detailed comparison of the cost-saving performance of the two proposed abort policies numerically.