Reliability analysis and optimization of multi-phased spaceflight with backup missions and mixed redundancy strategy

Due to the widespread applications, the reliability analysis and optimization of phased mission systems (PMSs) have attracted progressively attention, especially in the aerospace industry. To achieve high reliability, the redundancy mechanism is commonly seen in the system design, as well as in the mission design. On the other hand, except for the mission success probability (MSP), the crew survival probability (CSP) is more critical in manned spaceflight. Therefore, the emergency escape module is required in the design. To involve this factor in the analysis of PMS, a PMS-BDD based model is proposed for the system CSP evaluation of PMSs with backup/ rescue missions in this article. And an improved K-mixed redundancy strategy is also proposed for system optimization. Then, an adaptive PSO is used for the system CSP optimization. At last, a propulsion system with an escape module for a spacecraft is shown as an example. And the discussion on the optimization result is also provided.