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  Space Shuttle Main Engine Electro-Mechanical
  Valve Actuation (SSME EMVA)

Problem: Elimination of hydraulics may be a potential future vehicle upgrade. The SSME would therefore be required to actuate the five engine propellant valves without hydraulic power.
Solution: Actuation can be accomplished with electro-mechanical actuators coupled to low torque valves. Elimination of hydraulics would simplify the engine interface and system complexity and improve overall reliability. Electric actuation would eliminate the intensive maintenance and operability impacts associated with hydraulic systems.
Initial Operation Date: Contingent in vehicle decision
Mission number, Contingent in vehicle decision
Phase III Upgrade
Technology Goal: The enabling technology for this system is to reduce valve torque requirements to a level that the electro-mechanical actuator's envelop, weight and power characteristics do not adversely impact SSME requirements. Integration of a prototype low torque Chamber Coolant Valve with a commercial EMA has been demonstrated on a SSME to a technology readiness level %. SSME transient performance, system robustness and reliability with EMVA would require full scale development engine test validation. The technology is transferable for all future reusable propulsion system (i.e. LFBB).
Goals Supported: 1) Fly Safely
2) Meet the Manifest
3) Improve Supportability
4) Reduce Cost
5) Support HEDS


Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 04/07/2002
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