MIT engineers have demonstrated the first fully 3D-printed, droplet-emitting electrospray engine.
Shoe box-sized CubeSats are becoming increasingly important in space exploration and collecting scientific data. But these tiny satellites need efficient and precise propulsion systems for in-orbit maneuvers.
One promising solution is electrospray engines, which use electric fields for propulsion.
The standard electrospray engines are effective, but their complicated and costly manufacturing restricts their use. MIT has developed a new, innovative approach to address this limitation.
For the first time, engineers have created a fully 3D-printed electrospray engine that emits droplets. Notably, the production of this innovative device is quick and much cheaper than traditional thrusters.
This 3D printing technology could allow astronauts to manufacture satellite engines in space, eliminating the need for Earth-based launches.
The device requires a complex hydraulic system to store and regulate the flow of liquid, efficiently shuttling propellant through microfluidic channels to a series of emitters. MIT
Advanced 3D printing techniques
Electrospray engines use electric fields to create high-speed jets of charged droplets to propel spacecraft. These small engines are well-suited for CubeSats used in research.
Moreover, these engines are more fuel-efficient than chemical rockets, making them ideal for orbital adjustments.
In this new work, the research team combined two different 3D printing methods: two-photon printing for the intricate emitter modules, and digital light processing for the larger manifold block.
This helped in creating a complex device with both large and tiny, interconnected parts.
A prototype 3D-printed thruster with 32 electrospray emitters was built and tested. This demonstrated stable propellant flow and generated equal or greater thrust than current droplet-emitting electrospray engines.
The emitter array consists of eight modules, each containing four individual emitters. These 32 emitters must operate in a coordinated fashion as a single, interconnected system.
Higher thrust efficiency
The emitter modules were made using two-photon printing, which uses a focused laser to solidify resin. This precise method allowed for the creation of sharp emitter tips and narrow, consistent channels for propellant.
The emitter modules are housed within a manifold block, which both secures them and provides propellant.
Instead of using two-photon printing for the manifold block (due to size and throughput limitations), the researchers employed digital light processing. This method solidifies resin layer by layer using a projector.
“Each technology works very well at a certain scale. Combining them, so they work together to produce one device, lets us take the best of each method,” said Luis Fernando Velásquez-García, a principal research scientist at MIT.
Researchers tested the 3D printing materials to ensure they wouldn’t react with the conductive liquid propellant. Compatibility is crucial to prevent corrosion or cracking.
In testing, the 3D-printed prototype achieved higher thrust efficiency than larger, more expensive chemical rockets. Moreover, it surpassed the performance of current droplet electrospray engines.
Interestingly, adjusting the voltage allowed for greater thrust control. This voltage modulation could simplify the engine design, resulting in a lighter, and more efficient thruster.
“We were able to show that a simpler thruster can achieve better results,” Velásquez-García stated in the press release.
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The researchers ultimately aim to demonstrate a CubeSat using their 3D-printed electrospray engine for both its operational maneuvers and its deorbit.
The findings were published in the journal Advanced Science.
Mrigakshi Dixit Mrigakshi is a science journalist who enjoys writing about space exploration, biology, and technological innovations. Her work has been featured in well-known publications including Nature India, Supercluster, The Weather Channel and Astronomy magazine. If you have pitches in mind, please do not hesitate to email her.
