Applications of Microthrusters for Satellite Missions and Formation Flights Scenarios

Low thrust engines (e. g. ion thrusters, arcjet engines, magneto-plasmadynamic systems) with high specific impulses became important tools for recent space missions (SMART 1, Hayabusa 1 ...). Although in particular ion thrusters demonstrated high reliability and long term stability, their performance is not sufficient for satellite systems requiring drag-free, high precision attitude and orbit control. An increasing number of missions for geodetic purposes or astronomic science goals as well as formation flight scenarios with precise distance control between single satellites require much better propulsion systems enabling thrust control down to the sub-mu N level. Micropropulsion systems must be able (i) to compensate disturbing forces preventing the spacecraft from flying on an ideal geodetic orbit and (ii) to balance tidal forces and spacecraft dynamics in formation flight scenarios. Recent developments (e. g. Field Emission Electric Propulsion - FEEP) are promising but so far not sufficient approaches, wherefore laser induced ablative thrusters are completely new concepts still under study.