Feasibility of Electrostatic Microparticle Thrusters

The paper discusses the feasibility of electrostatic propulsion which uses microparticles as propellant. Two novel thruster concepts are proposed which differ both from electrospray-like colloid thrusters and nano field-emission thrusters, which extract nanoparticles from suspensions. It is shown that particle charging in a plasma is not sufficient for electrostatic acceleration. Moreover, it appears technically difficult to extract charged particles out of a plasma for subsequent acceleration without being discharged. It is proposed to charge particles with low secondary electron emission using an energetic electron beam, e.g. with graphite particles surface potentials of –90 V can be obtained. Another promising concept is charging by contact with needle electrodes at high electrostatic potential (~ 20 kV), which allows for maximum possible specific charges.