Advanced Rocket Propulsion Technologies

Electromechanically Actuated (EMA) valves are generally defined as valves operated by electornically controlled motor drive systems, rather than by valved hydraulic or pneumatic systems. Marotta Scientific Controls reviewed the current state-of-the-art for EMA ball valves in the cryogenic rocket propulsion industry and performed a trade study comparing these valves to a new and innovative valve design which significantly reduces the operating power. The trade study focused on valve attributes such as envelope, weight, power, torque loads, reliability, producibility, cost and leakage. A sample specification was used to baseline each of the various types of valves so that a one-to-one trade could be successfully completed. Learning from the shortcomings of the present state-of-the-art, the innovative electromagnetically actuated (EMA) cryogenic valve innovation has been designed to provide high performance and reliable, long life operation in a unique simplified, lower cost configuration. This unique EMA valve concept has been specially designed to eliminate or reduce considerably several of the major loading torques (e.g. Bearing Friction Torque, Seat Scrubbing Friction Torque, Stem Seal Friction Torque, Aerodymanic Torque, Pressure Unbalance, Spring Loads). Reducing the torques facilitates the design of a lower power EMA.