Optimal mission abort policy for systems in a random environment with variable shock rate

- A mission that can be aborted in cases of danger is considered.
- A random shock model is used to represent the random environment.
- Mission success probability and system survivability are evaluated.
- Both internal failures and external impacts are considered.
- Optimal mission abort policy is analyzed based on the model.

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. Specifically, the mission objectives of these systems can be aborted in cases where a certain malfunction condition is met or some obstacles/ hazards occur. Then a rescue or recovery procedure is initiated to enhance survivability. Traditional system reliability models typically cannot address the effects of mission aborts, and thus are not applicable to analyzing systems subject to mission abort requirements. In this paper, we first develop a methodology to model and evaluate mission success probability (MSP) and survivability of systems experiencing both internal failures and external shocks. We consider a policy when a mission is aborted and a rescue procedure is activated if the m-th shock occurs before time ξ since the start of a mission. We demonstrate the tradeoff between system survivability and MSP that should be balanced by the proper choice of the decision variables m and ξ. An illustrative example of a mission performed by an unmanned aerial vehicle is presented.