University of Melbourne Students Hot-Fire 3D-Printed Rocket Engine at Race2Space

Student Rocket Team Proves 3D-Printed Regenerative Cooling Is No Longer Just for Professionals

A three-person capstone team at the University of Melbourne didn't just build a rocket engine. They built one that professional programs would recognize. The engine, nicknamed Slinky, completed five clean hot fires at Race2Space in the United Kingdom this month, reaching a maximum thrust of 5.4 kilonewtons and taking first place in the LOX bipropellant category.

The milestone isn't the thrust number. It's the cooling. Slinky uses regenerative cooling, which routes one of the two liquid propellants through microchannels machined directly into the combustion chamber wall. That cooling method is standard in professional liquid propulsion but almost never appears in student projects because the plumbing is difficult to assemble by hand. Additive manufacturing removes that constraint. The cooling channels are printed as geometry rather than built from tubes and fittings.

The students worked with CSIRO's Lab22 additive manufacturing center, which printed the engine on a Nikon SLM Solutions 280 2MA laser powder bed fusion system in a copper alloy chosen for thermal conductivity. The finished engine weighs roughly 6 kilograms and is about the size of a large pineapple. The team hopes to fly Slinky in a future rocket, which would make it more than a competition entry.

Why This Matters Beyond Student Rocketry

What moved here isn't the technology itself. Regenerative cooling has existed for decades. What moved is the barrier to entry. A three-person team with access to a national lab's printer can now attempt a design that used to require a full engineering department and months of skilled fabrication work. That's the pattern repeating across additive manufacturing: the complexity lives in the digital design, not the assembly.

The University of Melbourne team isn't alone. Ireland's ULAS HiPR group fired its own 3D-printed liquid rocket engine at the same competition earlier this year, and UCSD's SEDS team flew a printed engine a decade ago without regenerative cooling. The line between student projects and professional hardware keeps moving because the printers keep getting better and the design tools keep getting faster.