MIT Engineers 3D Print Electrospray Engine Ideal for Small Satellites

Have you heard of electrospray engines? These propulsion systems involve applying an electric field to a conductive liquid, generating a high-speed jet of tiny droplets capable of propelling a spacecraft. Such miniature motors are particularly suitable for small satellites, known as CubeSats, which are used in academic research. Furthermore, electrospray engines can use fuel more efficiently than conventional chemical rockets, making them particularly suitable for precise movements in orbit.

Traditionally, electrospray engines are manufactured using expensive and time-consuming semiconductor cleanroom fabrication, which limits the range of applications and the number of manufacturers. To circumvent this problem, MIT engineers developed an electrospray motor made entirely using 3D printing.

3D CAD models of the electrospray thruster design explored in this study: a) exploded view of assembled thruster made of a manifold block, an array of emitter modules, and an extractor electrode (during the experiments, the central emitter module was replaced with a non-functional module to ensure uniform emitter operation across the other eight emitter modules); b) close-up of an emitter module composed of an array of four emitters, each fed by a long, narrow, and winding capillary.

How do electrospray engines work? Well, they have a reservoir of propellant that flows to a series of emitters via microfluidic channels. A strong electrostatic field is applied to the tip of these emitters, which triggers an electrohydrodynamic effect. Then, this shapes the liquid into a cone-shaped meniscus that ejects a stream of high-speed charged droplets from its apex, generating thrust.