Australian Students Win Race2Space With a 3D-Printed Regeneratively Cooled Rocket Engine

A student team did what used to require a factory

A three-person capstone team at the University of Melbourne has test-fired a 3D-printed liquid bipropellant rocket engine that uses regenerative cooling, winning the LOX bipropellant category at Race2Space 2026 in the UK. The engine, nicknamed Slinky, produced 5.4 kilonewtons of thrust across five hot-fire tests in a single day.

Regenerative cooling routes one propellant through channels inside the combustion chamber wall before injection. That design is standard on professional engines but extremely difficult to build by hand. Traditional methods require tubes brazed together or jackets machined and welded, each seam a potential failure point. Laser powder bed fusion changes the equation. CSIRO's Lab22 printed the engine on a Nikon SLM Solutions 280 2MA system in Clayton, Victoria, using a copper alloy selected for thermal conductivity. The cooling channels are part of the wall itself, not added later.

Why this matters for more than student rocketry

Richard Sandberg, Chair of Computational Mechanics at the University of Melbourne, supervised the capstone. He sees the result as evidence that computational design plus additive manufacturing can compress development cycles. The same three-person team produced flight-ready hardware in the time it used to take a small company to finalize a design.

Other student teams are reaching the same threshold. Ireland's ULAS HiPR team announced its own 3D-printed LOX IPA engine earlier this year. A decade ago, the comparable student milestone was UCSD's Vulcan-1, which flew without regenerative cooling at all. The barrier was always fabrication skill, not physics. 3D printing removes that barrier.

The test campaign

Slinky weighed roughly six kilograms, about the size of a large pineapple. The team transported it to the UK for Race2Space and completed throttling runs as well as steady-state burns. Stuart Davis and Brooke Doolan, two of the three masters students behind the project, said the outcome opens the door to more complex propulsion designs within the university's Aerospace and Rocket Engineering Society. The team hopes to fly Slinky in a future rocket.

What kept regenerative cooling out of student hands was construction complexity. Printing the channels into the wall replaces that labor with geometry. That is why a three-person capstone team could attempt a design normally reserved for professional programs, and get five clean fires on the first campaign.