An expert systems approach to automated fault diagnostics

The implementation of the life support function on the Space Station will probably have to be based on regenerative life support techniques. It is essential that the regenerative subsystems operate with minimum attendance from the crew. However, the results of extensive testing show that uninterrupted subsystem operation over long periods of time (e.g., months) is not easy to achieve. In order to achieve longer periods of time on line for these subsystems, it is necessary that the Environmental Control and Life Support System (ECLSS) designers focus their attention on technologies which will permit both increasing the mean time between shutdowns and decreasing the time for which a subsystem is down for fault diagnosis and maintenance. With the aim to be able to perform the fault diagnosis on line rather than after the subsystem has shut down, an expert systems approach to automated fault diagnostics is considered. A description is given of a program, designated CS-1 'FIXER' for fault isolation expert to enhance reliability.