MIT engineers have achieved a milestone in satellite propulsion technology with the world’s first fully 3D-printed electrospray engine, MIT News reports. This lightweight, cost-effective design is set to propel small satellites called CubeSats, widely used in academic research. The miniature engines can potentially be made directly aboard spacecraft, replacing the conventional, high-cost manufacturing methods.
Pushing boundaries in space research
Electrospray engines function with the help of an electric field applied to a conductive liquid, generating high-speed jets of tiny charged droplets that produce thrust. Incredibly efficient for precise, in-orbit maneuvers, these engines have never been easy to produce. Relying on expensive semiconductor cleanroom fabrication created a manufacturing challenge that limited accessibility and application.
To democratize access to space hardware, the research team at MIT have developed a modular 3D-printing workflow that combines two advanced additive manufacturing techniques, seamlessly integrating both macroscale and microscale components. Their proof-of-concept thruster consists of 32 electrospray emitters and delivers thrust performance comparable to if not exceeding traditional designs.
“Using semiconductor manufacturing doesn’t match up with the idea of low-cost access to space,” said Luis Fernando Velásquez-García, a principal research scientist at MIT’s Microsystems Technology Laboratories (MTL) and senior author of the study. “We want to democratize space hardware.”
A modular approach to next-gen 3D printing
Supported by a MathWorks fellowship and the NewSat Project, and published in Advanced Science, the study explains that the electrospray engine contains a reservoir that supplies propellant to emitters, which eject high-speed droplets when an electrostatic field is applied. The key challenge is to fabricate sharp emitter tips and microfluidic channels while maintaining structural integrity.
To achieve this, engineers leveraged two types of vat photopolymerization printing (VPP). They made the fine emitter modules using two-photon printing, a technique that enables ultra-precision at the microscopic level. Meanwhile, the larger manifold block, responsible for housing and supplying propellant to the emitters, was fabricated using digital light processing, a more common and efficient technique for larger components.
Optimizing performance and efficiency
In addition to manufacturing, the team ensured material compatibility with the conductive propellant and devised a precise assembly technique to prevent any leaks or misalignments. Their fully 3D-printed prototype outshone existing droplet-based electrospray engines and proved more efficient than larger chemical thrusters.
Another discovery researchers made is that varied voltage applied to the engine allowed for a wider range of thrust with no need for complex valves or pressure regulators. “We were able to show that a simpler thruster can achieve better results,” Velásquez-García concluded.
Looking ahead, the team intends to optimize voltage modulation, increase the density of emitter arrays, and explore multi-electrode configurations. Ultimately, scientists plan to demo a CubeSat that operates and de-orbits using a fully 3D-printed electrospray engine. Way to go, MIT! This innovation isn’t just your average rocket science, it’s a giant leap for small satellites.
