Physical Sciences Inc. and AMPAC In-space Propulsion 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 storable, low toxicity, monopropellant as its working fluid. Under this SBIR program we propose to investigate applications of this monopropellant to the design of in-space propulsion systems appropriate for NASA planetary spacecraft and missions. In Phase I, we propose to experimentally characterize the propellant ignition and combustion processes in detail and use the data to develop design concepts for a liquid monopropellant thruster. In Phase II, we propose to develop and deliver a small scale proof-of-concept engineering prototype thruster. Upon successful technology development under the SBIR program, full-scale protoflight and space flight propulsion systems applicable to specific missions will be developed in Phase III NASA programs.