Description: Busek proposes to develop a high performance, non-toxic storable, "green" monopropellant thruster suitable for in-space reaction control propulsion. The engine will deliver 100N (~25lbf) vacuum thrust with specific impulse exceeding 240sec. Estimated Isp-density is on the order of 348 sec-g/cc, a 48% increase from the state-of-the-art hydrazine systems. The most important feature that sets this thruster apart from other similar devices will be the use of an innovative, long-life catalyst. This proprietary catalyst, constructed without any bed plate or ceramic substrate, was recently demonstrated in Busek's 0.5N micro thruster. It has shown the ability to suppress catalyst-related performance degradation problems that often plague green monopropellant thrusters. The proposed Phase I program will focus on developing a 5N green monopropellant thruster by scaling up the long-life catalyst design from the 0.5N thruster. Both empirical and modeling works are proposed to validate the scaling theory. Thruster performance will be evaluated based on hot-firing test results that include c* and vacuum thrust measurements. The Phase I findings will lead to the design of a full-scale, 100N green monopropellant thruster to be developed in Phase II.

Benefits: Potential NASA applications of the green monopropellant rocket include missions to the moon, NEO and Mars. As with SOA reaction control rockets the green monoprop is radiation-cooled and restart-able, making it a simple yet reliable propulsion option. Storability and reliability are important factors especially for missions supporting NASA's manned spaceflight. The low toxicity of the propellants will benefit both the ground crew and the astronauts. Without the need for excessive safety measures, overall operational cost can be reduced. The proposed technology is easily scalable in the 0.1-100N thrust range, which opens the door for small- and nano-satellite applications.

Market size for green monopropellant thrusters is very large. In addition to NASA, all branches of the military have potential interests in such propulsion for tactical or in-space applications. The non-toxic storable feature of the propellants makes them prime candidates for preloaded systems that can accommodate speedy launch operations. Because the proposed thruster has the potential for extended life without performance degradation, developers of small satellites will likely consider it for both reaction control and primary propulsion. This versatility will help broaden market access. A successful Phase II program will lead to direct sales or licensing of the green monopropellant thruster and its novel, long-life catalyst.