28-day extended-duration orbiter automated fault detection, isolation, and recovery concept definition and proof-of-concept development

This paper describes concept definition and proof-of-concept development of an automated on-board fault detection, isolation, and reconfiguration (FDIR) system for the extended-duration orbiter (EDO). The EDO is a modified Shuttle orbiter that can perform 16- to 28-day missions. The design of EDO FDIR requires automating existing orbiter FDIR procedures while minimizing changes to existing hardware and software. Automation will be achieved by extensive use of expert system technology. Two software architectures, a fully distributed one and a hierarchical failure-driven one, were identified. The hierarchical failure-driven approach was selected for proof-of-concept development. Prototypes were developed for the power reactant storage and distribution and fuel cells subsystems to recognize, isolate, and provide reconfiguration instructions for a limited number of malfunctions.