Development of an Indium mN-FEEP Thruster

Future scientific satellites require precision pointing capabilities with thrust levels from sub-µN to the mN-range and very low thrust noise. Since 2004, a dedicated mN FEEP thruster based on the space-proven ARC Indium Liquid-Metal-Ion-Sources is under development. This paper gives an overview of the development program and its achievements. A mN FEEP thruster with a specific impulse close to 8000 s could be demonstrated with excellent efficiencies and a size comparable to present µN FEEP thrusters. Nomenclature e = electron charge f = beam divergence loss factor g = Earth’s gravitational acceleration ISp = specific impulse η = mass efficiency Droplet m & = ion mass flow