Development of a Power Efficient, Restartable, "Green" Propellant Thruster for Small Spacecraft and Satellites

Development of a Power Efficient, Restartable, "Green" Propellant Thruster for Small Spacecraft and Satellites

This paper details the design, developmental, and testing of an innovative, flight-weight, "green" hybrid propulsion system of a size that is applicable to a wide range of small spacecraft missions. The system uses environmentally friendly compressed gaseous oxygen and ABS-plastic as propellants, and is designed as a "drop in" replacement for monopropellant hydrazine spacecraft propulsion systems. The design leverages robotic manufacturing (RM) to build the fuel grain and other system components including the nozzle, motor case, and injector cap. The inherently safe design well-suited for rideshare missions. Test results from a medium scale laboratory weight motor and a small flight weight thruster are presented. The achieved laboratory specific impulse exceeds 230 seconds, and this value extrapolates to greater than 300 seconds under spaceflight conditions -- significantly higher than can be achieved by hydrazine-based systems. A small 22-N thruster has been successfully design and built. Preliminary tests have shown capability to perform multiple restarts with very little startup latency.