scope:

Abstract:

Reduced torque output of the orbiter's electromechanical actuators has been a problem for the Shuttle Program. It has resulted in unplanned work to test, remove, and refurbish the actuators. Disassembly and inspection has revealed that the torque reduction is a result of problems with the torque limiters and the motor clutch/brake assemblies in the actuators. Refurbishment is a lengthy process because of the difficulty involved in setting the torque limiter to operate through the required temperature range. The next generation of actuators should have a better design, or the mechanical system should be capable of withstanding the maximum output loads of the actuator.