Physical Sciences Inc. (PSI) and Orbitec Inc. propose to develop a unique chemical propulsion system for the next generation NASA science spacecraft and missions that is compact, lightweight, and can operate with high reliability over extended periods of time and under wide range of thermal environments. The system uses a new storable, low toxicity, liquid monopropellant as its working fluid. In Phase I, we have demonstrated experimentally the critical ignition and combustion processes for the propellant and used the data to develop thruster design concepts. Phase I work achieved TRL 3. In Phase II, we propose to develop and demonstrate in the laboratory a proof-of-concept prototype thruster. Phase II will achieve TRL 4+. We envision follow-on Phase II Enhancement (Phase II E) and Phase III programs to advance the TRL to 5 and 6, respectively. Phase III will be the development of a full-scale protoflight propulsion system applicable to a class of NASA missions. On both Phase II E and Phase III programs, we will collaborate with specific NASA programs and the industry to address the cost share component. Following a successful Phase III a space flight demonstration on a NASA mission will advance the TRL to 7.