Indium field emission electric propulsion microthruster experimental characterization

Abstract

Indium liquid metal ion sources have been flying for more than 10 years on a variety of spacecraft for spacecraft potential control and as the core element of mass spectrometers. Since 1995, a dedicated indium field emission electric propulsion (In-FEEP) thruster has been under development and recently passed a 2000-h endurance test. The In-FEEP thruster is a micropropulsion device for the 1-100 muN thrust range with low thrust noise and high resolution. The latest performance characteristics including direct thrust measurements and beam profiles are summarized. This information is very important for many upcoming missions that require ultraprecise drag-free control such as the Gravity Field and Steady-State Ocean Circulation Mission, LISA, Terrestrial Planet Finder/Darwin, or SMART-2.