Research and Development of Carbon Nanotube Cathodes for Electric Propulsion

Abstract

In recent years there have been demands for small, simple, low-power electron sources for applications such as miniature electric propulsion systems, electrodynamic tethers, scientific applications, and spacecraft charge control. To satisfy these demands, we have started the research and development of carbon nanotube (CNT) cathodes. A laboratory model of a 0.5 mA-class CNT cathode was designed, fabricated, and tested. The emitter-to-gate separation distance and slit aperture width were varied to find effective configurations. In the selected geometrical conditions, the desired emission current of 0.5 mA was obtained at an applied voltage of approximately 600 V and with a drain current less than 10% of the emission current.