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Flow Regulators for Electric Propulsion
The availability of compact, new generation Flow Regulators for application to different Electric Propulsion (EP) Technologies/Thrusters (e.g. Hall Effect Thrusters, Gridded Ion Engines of both the electron bombardment and RF type, and Multi-Stage Plasma Thrusters) can be considered a key issue for increasing the EP market penetration and the possibility for EP Systems to be embarked on board forthcoming GEO, MEO and LEO satellites. In particular the “very fine” regulation/conditioning of propellant, in terms flow rate, is regarded as a fundamental issue for increasing flexibility and versatility of EP systems dedicated to the attitude/orbital control and manoeuver of spacecraft/satellites. Selex ES has completed, under an ESA technology contract, the qualification at component level of the High/Low Pressure Regulation & Insulation Valve (HP/LP RIV). This component features both tank high pressure insulation and “analog” very fine gas (propellant) flow regulation capability and implements the actuation element of a “closed loop” flow regulation equipment. The HP/LP RIV valve complements the previously developed GAIA thruster piezo valve ( this latter is used in low pressure application only ), featuring an alternative piezoelectric actuator design using much stronger springs but still keeping the smooth and progressive variation of the actual open area offered to the gas flow. The very low internal/external leak rate ( < 10-6 ssc/s of He) and piezo actuator power consumption as also kept. The HP/LP RIV valve has been currently qualified at an inlet pressure up to 150 bar, and a mass flow rate up to 30 mg/s (Xe). The HP/LP RIV may support different flow regulation task/strategies either paired with a Mass Flow Sensor , or directly using as feedback a thruster variable to be regulated by gas flow regulation , or may be driven according to algorithms evaluating real time thruster behavior. In addition, since this valve couples high pressure design with fine regulation capability, new propellant management configurations may be conceived featuring direct connection to the tank (“Single-Stage Flow Regulation”). A single stage configuration validation test, starting with low pressure, has been foreseen at ESA Electric Propulsion Laboratory (EPL) with flow regulation concept applied to a small Hall Effect Thruster developed by ALTA. The test program has been agreed , Selex ES has delivered the HP/LP RIV valve to ESA/ESTEC. For covering the application field of very low and ultrafine flow regulation equipment Selex ES has designed, manufactured and qualified e regulation valve based on a piezo ring benders actuation mechanism. This valve, named Piezo Valve (PV) is the actuation element of the Cold Gas Micro Propulsion Thruster (MT) used for GAIA mission and is currently flying on GAIA spacecraft
Noci Giovanni Enrico, Matticari Giovanni, Fallerini Leonardo
Paper for Seminar/Symposium/Conference
Space Propulsion 2014 - Conference (19–22 May 2014, Cologne, Germany)
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