A new rocket is designed for its own destruction, eating itself as it makes its way through Earth’s atmosphere to power its journey.
A group of researchers from the University of Glasgow has built the first unsupported autophage rocket engine, which uses waste heat from combustion to melt its plastic fuselage and use it as fuel. The design was presented at the American Institute of Aeronautics and Astronautics SciTech Forum in Orlando, Florida, on Wednesday, and is based on an idea that was patented in 1938.
“The concept has been around since the 1930s, with the idea that an infinitely staged rocket could be the most efficient way of reaching orbit,” Patrick Harkness, professor of exploration technology at the University of Glasgow, who led the development of the design, told Gizmodo in an email. “The difficulty is that it has significant complexity and, until recently, there has been less of a business case for small payloads that are best served by autophage.”
The engine uses high-density polyethylene plastic tubing as fuel, which burns with the main propellants: liquid propane and gaseous oxygen. As the rocket launches to orbit, it burns the plastic tubing, which is fed into the engine’s combustion chamber, until it is no more. Since it requires less propellant packed from Earth, the rocket has more room to carry payloads to space compared to other vehicles of similar mass.
The rocket is named Ouroborous-3 after the ancient Egyptian symbol of a serpent eating its own tail, devouring itself to be reborn. The researchers behind the design test-fired the prototype rocket engine at the MachLab facility at Machrihanish Airbase, producing 100 newtons of thrust in a series of controlled experiments.
The first test was carried out in 2018. With the most recent test, the researchers demonstrated that more energetic liquid propellants can be used for the engine, and that the plastic fuselage can withstand the forces required to feed it into the engine.
The tests also showed that the rocket’s burn can be controlled, throttled, restarted and pulsed in an on and off pattern. Next up, the researchers want to develop a flight weight engine prototype and use liquid oxidizers.
“We aim to scale up by around two orders of magnitude, but not much further because our niche is in nanolaunchers,” Harkness said. The rocket could be used to carry tiny nanosatellites into orbit directly as opposed to more costly missions on conventionally fueled rockets.
Another main advantage to the rocket is that it devours itself before reaching orbit so it doesn’t remain as a wandering pile of hardware in space, adding to the growing problem of space debris.