In “Trottenberg et al 2008 New J. Phys. 10 063012„, the concept of electrostatic micro-particle propulsion is explored. Advantages of such a propulsion concept would be, for example, high density propellant storage and the possibility to use propellant materials available in space, e.g. asteroid regolith (In-Situ Resource Utilization). One of the particle acceleration methods proposed, involves the use of sharp needles to electrically charge and accelerate small particles (100nm – 1µm). The novelty of the approach proposed here is to use a magnetic field to shape the propellant itself - for example, iron powder - into sharp spikes. The tips of the spikes would allow to transfer high charge amount to the particles because of the local high field density. Obtaining high particle charge/mass ratio is fundamental in order to achieve useful acceleration levels. The particle emission takes place at the tip because the magnetic force, which tends to keep the particles together, is there overcome by the force produced by the electric field, which tends to keep the particles apart. Furthermore, as the magnetic field decreases with the cube of the distance, while the electric field decreases with the distance squared, as soon as the particle is detached from the bulk, the effect of the magnetic field will become negligible, allowing a strong acceleration by the electric field. The spikes will be continuously regenerated using mechanical vibration or varying the magnetic field. Depending on the particle dimensions and the applied voltages, specific impulses comparable to chemical thrusters can be obtained. A rough assembly proving the novel particle emission concept has already been tested at FOTEC, with promising results. The proposed activity consists in the development of a prototype and testing in vacuum, with the aim to check the robustness of the concept and to try to determine the speed of the emitted particles and calculate thrust and specific impulse.
