Electrospray Thrusters as Precise Attitude Control Actuators for Small Satellites

Abstract

The purpose of this work is to describe the use of electrospray propulsion devices as miniaturized actuators for precise attitude control of small satellites, including CubeSats. Electrosprays are nonpressurized, passively fed, compact and fuel-efficient electric thrusters capable of producing impulse bits in the or lower, depending on the configuration. These characteristics have the potential to allow for long-term pointing in the arcsecond range or better with practically no jitter. Experimental work is performed on a magnetically levitated testbed in vacuum to demonstrate the actuation characteristics under nonoptimal control. It is found that, subject to a noisy attitude sensor and external perturbations, electrospray thrusters are capable of producing pointing accuracies around a given set point of 22 arcseconds error during 10 h on a platform similar in size and mass to a 1U CubeSat. The implementation of such capabilities could complement or eliminate the need of reaction wheels and magnetorquers, especially in missions beyond low Earth orbit, while including propulsive capabilities for additional maneuverability in technology development or scientific missions.