Electrospray Propulsion Systems for Small Satellites

For this paper, Busek presents its heuristic for evaluating capability of propulsion systems for spacecraft at the CubeSat level, which utilizes the well-known rocket equation, but recognizes that for very small spacecraft the mass ratio (initial mass/final mass) has much greater influence than the specific impulse. This provides a simple basis of comparison for various propulsion technologies, as well as prioritization of development objectives for improving overall baseline capabilities. Examples of selected propulsion technologies are presented for illustration, followed by an introduction of Busek’s different propulsion solutions for Cubist-scale spacecraft. Finally, Busek discusses its proposed electrospray thrusters for the DARPA Phoenix mission, with a brief overview of the Phoenix objectives and how the rocket equation heuristic, plus additional system considerations, led to selection of electrospray propulsion as the optimal mission solution