On-board preventive maintenance for long-life deep-space missions: a model-based analysis

The long-life deep-space missions associated with NASA's X2000 Advanced Flight Systems Program creates many unprecedented challenges. In particular the stringent constraints on the mass of a spacecraft and the power on-board preclude traditional fault tolerance approaches which rely on extensive component/subsystem replication, calling for novel approaches to mission reliability enhancement. In this paper we present an approach to on-board preventive maintenance which rejuvenates a system via periodical duty switching between system components, slowing down a system's aging process and enhancing mission reliability. By exploiting the nondedicated system redundancy hardware and software rejuvenation are realized simultaneously without significant performance penalty. Our model-based evaluation confirms a potential for significant gains in mission reliability from on-board preventive maintenance and provides to us useful insights about the collective effect of age-dependent failure behavior residual mission life, risk of unsuccessful maintenance and maintenance frequency on mission reliability.