Multi-Scale Investigation of a Colloid Micro-Propulsion System

Electric propulsion is highly efficient for both deep-space and near-earth applications and it is an excellent candidate for small satellites. A colloidal electrostatic thruster for small spacecrafts is investigated in the present paper. A multi-disciplinary approach (encompassing several scales of modelling: fluid, particle trajectory and molecular modelling) is adopted in order to gain an increased understanding of complex underlying physical processes. The governing factors are accessed in order to obtain the onset and maintenance of a focused beam of droplets or ions. The trajectories and characteristics of the droplets and ions are investigated and multi-electrode configurations are parameterized by simulations. The flow from the capillary needle, just before the droplets are formed, is also investigated by fluid methods. The molecular modelling provides interesting information on the different modes of emission from the perspective of the stability of the ions. The multi-scale results obtained are fully discussed and the valuable insights provided by the simulations are also currently fully helping in the design of a laboratory model of an electric micro-propulsion system for small spacecrafts.