Controls Design for the Space Station Freedom Atmosphere Revitalization Subsystem

This paper summarizes the design approach taken to control the Atmosphere Revitalization subsystem hardware for Space Station Freedom. The hardware consists of three subassemblies and numerous distributed components, all of which interact to provide the habitable atmosphere on the station. The design includes several automated functions to enhance safety and reliability and to minimize ground and flight crew time during subsystem initialization, startup and nominal operations. These include; built in test, "smart" transitioning algorithms, and a number of override commands. Another unique feature of this design centers around the process and tools used in its development. These processes and tools have a broad-based applicability across industry for controls design and verification prior to implementation and are also discussed.