Development of A Colloid Micro-Thruster For Flight Demonstration on the Emerald Nanosatellite

A colloid thruster functions by electrostatically generating and accelerating sub-micron droplets of propellant to high velocities. The technology is attractive because of the weight and size of the integrated package, its high efficiency, low power consumption and inert propellant. The development of the thruster prototype at Stanford University is aimed for a proof-of-concept flight-testing on board a 20-kg university satellite. The thruster system incorporates a modular and expandable design that uses a software-programmable micro-controller to control the telemetry, propellant system, the high-voltage power systems, the operation of the thruster, as well as the interfacing with the satellite bus. The modularity of the system allows for testing of three thruster core designs. Single-emitter and multi-emitter arrays consisting 0.006 in OD / 0.002 in ID stainless-steel capillary needles were constructed and tested. The half-kilogram Colloid Micro Thruster (CMT) system measures 4 in by 4 in by 8 in, consumes 6 watts of total power, contains 10 ml of 2.0 M sodium-iodide/glycerol propellant, and is capable of producing up to 4 micronewton of thrust per needle emitter at up to 200 seconds specific impulse. The thruster system is being prepared for flight qualification for launch on a 2002 Space Shuttle mission.