Reservoir Scandate Cathode for Electric Propulsion

We propose to combine the two most powerful cathode technologies into one hollow cathode assembly for use in ion and Hall-effect thrusters. Together, these technologies will boost ion thruster performance and life beyond current art. Reservoir cathodes have demonstrated, in microwave tube environments, lifetimes beyond 100,000 hours with no drop in output. Scandate impregnated cathodes have demonstrated emission beyond 10 amps/cm2 at 800 degrees Cb(W) and emission levels over 100 amps/cm2 at under 1000 degrees Cb(W). This is over 200 degrees below comparable all-tungsten impregnated cathodes, the cathode normally used for space propulsion. High temperature is the great enemy of long cathode life. Longer-life cathodes are needed for interplanetary and lunar missions, as well as earth-escape and near-earth maneuvers. In Phase II, we shall continue developing the hybrid scandate reservoir cathode and perfect our stand-alone scandium-doped tungsten cathodes. We shall continue to improve our hollow reservoir technology. Then we will combine the two technologies into an integrated module.