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An Apollo Command Service Module Thrust Vector Position Servo Amplifier (TVSA), a component of the spacecraft's Stabilization and Control Subsystem. The TVSA, manufactured by Honeywell Corporation, provided the electrical interface between the command electronics and gimbal actuator for positioning the Service Propulsion System (SPS) main engine.
The TVSA received main engine actuator position and deflection rates (velocity) and forwarded that information to the Gimbal Position/Fuel Pressure Indicator on the main display console. In addition, it interpreted Automatic Thrust Vector commands issued by the Command Module Computer as well as manual commands originated by the crew inputs to the Rotation Controller, converting them to a clutch current which resulted in servo-actuator deflection and as a result, gimbaling of the SPS main engine.