RCS Jet Failure Identification for the Space Shuttle

Abstract

A software technique for onboard detection and identification of hard failures and leaks of the shuttle orbiter reaction control subsystem jets during the orbital flight phase is presented. The method uses only the gimbal angle and linear velocity measurements available from the orbiter inertial measurement unit. Uncoupled steady-state constant covariance extended Kalman filters with residual traps are employed for rotational and translational state estimation, and generalized likelihood techniques are used for failure identification. Rigid body simulations indicate station-level identification times of 1.2 seconds for primary jet hard failures and less than 70 seconds for primary jet leaks.