UK researchers build 'self eating' rocket that burns itself for fuel

Researchers at the University of Glasgow have built a rocket that can burn its fuselage as fuel and tested its performance at the Machrihanish Airbase in the UK. The research presented at the international AIAA SciTech Forum in Orlando, Florida, this week is based on an idea that was patented in 1938.

In the seven decades since humanity first launched a satellite, the space around the planet has been trashed with debris from previous missions. has reported on multiple occasions how this trash flying at speeds is a risk to human missions onboard the (ISS) and those planned for the future. While attempts are ongoing to develop mechanisms to remove this trash through various means, the research team led by Patrick Harkness, a professor of Systems Power and Energy at the University of Glasgow, has now built a prototype rocket that uses its own fuselage as fuel and prevents discard of rocket parts in space.

A century old idea Harkness team collaborated with researchers at the Dnipro National University in Ukraine and tested the "autophage" concept that was first proposed and patented in 1938. Derived from Latin, the term autophage means self eating and unlike conventional rocket designs that continue to carry emptied fuel tanks with them, could instead use it to further power its mission.

The concept allows the rocket to carry a greater payload into space when compared to conventional rockets of the same mass. In today's context, this could pave the way for the launch of multiple nanosatellites on the same mission instead of having to wait their turn on the subsequent launch of a conventional rocket.

How well does the rocket work? Harkness' team has dubbed their autophage rocket engine the Ouroborous 3 and uses high density polyethylene plastic tubing as fuel to be burnt alongside the main propellants, liquid propane, and gaseous oxygen. Waste heat from the main propellant combustion is used to melt the plastic and then feed it into the alongside the main fuel.

The concept was test fired by the researchers in 2018 first, but now a collaboration with Kingston University, the team was able to demonstrate that more energetic liquid propellants can be used and their plastic tubing is capable of handling the forces that feed it into the rocket engine. At tests conducted at the Machrihanish Airbase, the Ouroborous 3 generated 100 newtons of thrust in controlled experiments.

It also demonstrated that the rocket was capable of a stable burn, and the fuselage supplied a fifth of the total fuel required. This was a crucial step on the way to developing a viable flight concept for the rocket engine. The team was also successful in demonstrating that it could throttle, restart, and pulse the rocket engine in a phased manner, abilities that would be essential in controlling the rocket when heading to orbit.

"These results are a foundational step on the way to developing a fully functional autophage rocket engine," said Harkness in the press release. "Those future rockets could have a wide range of applications which would help advance the UK’s ambitions to develop as a key player in the space industry.".