Real time failure detection algorithm for the Space Shuttle main engine

A real-time fault detection algorithm for the Space Shuttle main engine (SSME) is presented in this article. The system for anomaly and failure detection (SAFD) has been successfully tested on the NASA Technology Test Bed (TTB)engine at Marshall Space Flight Center in Alabama. It is currently being tested on the NASA Stennis test stand A-1, and has already proved its capability by detecting a failure earlier than a plume observer, while the redline system did not even detect the fault. It detects failures during steady-state and power throttling engine operation by monitoring 24 engine parameters in a real-time manner. The signal averages are compared with upper and lower safety limits, and if a multiple of sensor outputs violate the limits then a fault is flagged.