Emissive Membrane Ion Thrusters and Their Applications

The mechanism of operation of a new thruster concept that utilizes solid-state ionic membranes to convert molecules into ions and transmit them to a surface from which they can be extracted into energetic beamlets thereby producing thrust is described. Results of recent experiments are used to estimate the performance of the thruster and the masses of various components required for it to perform typical satellite missions. A simple analysis is carried out over a range of specific impulses in terms of traditional mission performance parameters (thrustto-power and total impulse-to-wet mass ratios). These results are compared to corresponding values for state-of-the-art ion and Hall thrusters. The emissive membrane thruster is shown to enable operation at 20% to 50% greater thrust-to-power ratios and 20% to 100% greater total impulse-to-wet mass ratios for a typical thrusting time. It is argued that compared to existing electric thruster designs the Emissive Membrane Ion Thruster (EMIT) will also be much less expensive and complex and that it will offer substantial improvements in scalability and reliability.