Catalyst-Free, Highly-Throttleable, Electric Propulsion Thruster

The future of monopropellant thrusters is moving towards high performance green propellants based on hydroxyammonium nitrate (HAN) and ammonium dinitramide (ADN). Ideally, a multimode propulsion system will include a higher specific impulse thruster for maneuvers that require propellant conservation to complement a higher thrust chemical thruster, with both thrusters utilizing the same propellant. We propose to develop an electric thruster that operates on almost any monopropellant, while maintaining high performance over a wide range of operation. The key to success is the elimination of the catalyst bed, shown to be a hindrance for both high performance (HAN, ADN) chemical thrusters and electric propulsion. Elimination of the cat bed should also increase the throttling capabilities of the electric propulsion engine. This catalyst-free thruster will also overcome thermal and life issues of the catalyst bed and allow for utilization of almost any propellant imagined. In Phase I we successfully demonstrated the operation of our electrically catalyzed thruster operating on a surrogate monopropellant. Key technical challenges for Phase II include the liquid propellant injector and feed system. We have organized a well thought-out plan to attack and solve these issues early in the development, culminating in a complete green propellant electrothermal thruster system. BENEFIT: The US Military has a current requirement for multimode propulsion. Successful development of an electric propulsion thruster operating on a chemical monopropellant satisfies the need for higher specific impulse thruster to complete the multimode propulsion concept. In addition, any spacecraft that requires high delta-v could benefit from such a thruster. Non space propulsion applications include chemical processing and gas generators for aircraft APUs.