The study by MIT scientists, published in the journal Additive Manufacturing, is the first demonstration of a fully 3D printed thruster using pure ionic emissions for propulsion.
A 3D-printed thruster that emits a stream of pure ions can be an inexpensive and extremely efficient propulsion source for miniature satellites.
The nanosatellite engine, created by researchers at the Massachusetts Institute of Technology (MIT), is the first engine of its kind – it’s completely additive. It was created using a combination of 3D printing and hydrothermal growth of zinc oxide nanowires. It is also the first engine of this type to produce pure ions from fluids used to create thrust.
Pure ions make the engine more efficient than similar modern devices by giving it more thrust per unit of fuel flow, explained Luis Fernando Velazquez-Garcia, chief scientist at MIT’s Microsystems Technology Laboratories (MTL).
The thrust provided by a coin-sized device is meager. Force can be measured on a scale of several tens of micronewtons, with thrust about half the weight of one of the sesame seeds in a hamburger bun. But in a frictionless orbit environment, a CubeSat or similar small satellite can use these tiny thrusts to accelerate or maneuver with precise control.
Velasquez-Garcia emphasizes that the benefits of additive manufacturing open up new, low-cost opportunities for powering satellites.
The miniature thruster works electrohydrodynamically, producing a fine jet of accelerated charged particles that are ejected to create propulsion. The particles come from an ionic liquid. Its peculiarity is that it contains only ions. In the broadest sense of the term, ionic liquids are any molten salt, for example, molten sodium chloride at temperatures above 800 ° C.
In an MIT design, the 3D-printed case contains a reservoir of ionic liquid along with a miniature picket fence of emitter cones coated with zinc oxide nanowires hydrothermally grown on the surface of the cones. The nanowires act like wicks, transporting fluid from the reservoir to the emitter tips. When a voltage is applied between the emitters and the 3D-printed pull-out electrode, charged particles are ejected from the emitter tips. Researchers experimented with printing stainless steel emitters as well as polymer resin.