A method based on maintainability analysis to select and optimize the Orbital Replacement Unit

As the on-orbit period of the space station is so long, some of the payloads are inevitable to malfunction. To ensure the mission being completed, the failed payloads must be maintained. Considering the astronaut's maintenance capability and the special space environment, such as weightlessness and vacuum, the Orbital Replacement Unit (ORU) should be well-designed. This paper introduces an ORU's selection and optimization method, which is based on the payload's maintainability analysis, to simplify the maintenance operation. Furthermore, this method can help locate and isolate the malfunctioned payload easily and optimize the storage of spares on-orbit.