Study of an electrospray-based electric propulsion system for small satellites

Electric propulsion is highly efficient for both deep-space and near-earth applications and it is an excellent candidate for small satellites due to its inherent small size and high specific impulse. A colloid electrostatic thruster for small spacecrafts is investigated in the present work. The study aims to gain an increased understanding of complex underlying physical processes. A simulation approach was previously used to investigate the beam trajectories and have helped to design a laboratory model of the electrospray-based micro-thruster which has been characterized experimentally¹. Interestingly, simulations can offer insights into the flows within the electrospray and offer critical local information difficult to measure experimentally due to the small scales. Thus, an electrohydrodynamic modeling of the transition of a charged liquid interface into a cone is described via a coupled formalism. The governing factors are accessed in order to precisely predict the initiation of the electrospray as well as capture the cone-jet mode of a focused beam of droplets or ions. Furthermore, in order to build a matrix of multiple emitters for use in a nano-satellite, the phenomena governing the transition in the electrospray has to be clearly understood. The competing processes in the cone-jet mode essential for optimization of a large-scale micro-thruster are fully discussed and compared. Moreover, interesting mixed modes comprising charged droplets as well as ions are explored in order to increase thrust or specific impulse.