Rocket engine prototype successfully ignites fuel in mid-flight

A rocket that eats itself may be on the way. To reach orbit, a rocket must lift its own mass, the mass of its propellant, and the payload it intends to carry into space. But if rockets could burn their own parts for fuel, they could free up capacity for more important scientific projects and for transporting supplies. A team of engineers has built his first prototype of one of these “autophage engines.”

The concept of a rocket that eats its own parts was first patented in 1938, but it was difficult to implement on the huge rockets on which most launches have historically taken place, so no working prototypes were built. Not built. However, the popularity of small satellites has increased in recent years, driving demand for smaller, more efficient rockets that are not constrained by the need to carry huge weights into space.

Krzysztof Busdyk Researchers at the University of Glasgow in the UK have created a small prototype rocket engine that consumes its own fuel tank. It’s not powerful enough to launch something into space, but it still shows that the concept works. “By burning the fuselage, we are solving the problem of rocket miniaturization. So when we want to send a small payload into space, we can do it right away, without waiting for a rideshare mission on a larger rocket. ” he says.

The researchers will present their findings at the American Institute of Aeronautics and Astronautics SciTech Forum in Florida on January 10th. This engine was called his Ouroboros-3, named after the ancient symbol of a snake eating its own tail.

Like the iconic snake, this engine is designed to devour its own backend when it uses up the rocket fuel it contains. “When you run out of propellant, you have an empty tank with all the useless structural mass,” Buzdyk says. “So what we’re doing is expending that dead weight so that we don’t have to carry it around on the way up, so we can carry more mass into space.”

In the prototype, as the oxygen and propane that make up the engine’s main fuel are burned, a plastic tube that holds the fuel is also fed into the engine. This tube makes up up to one-fifth of the total propellant used in burns and provides approximately 100 newtons of thrust. This is only about four times the force required to crack an egg.

The team is currently working on a larger prototype capable of delivering about 1,000 newtons of thrust. This is about one-sixth of the thrust required for the engine to reach suborbital space, and about one-twentieth of the thrust. To get it back on track.

“Additional testing should allow us to scale up the rocket… [but] In some cases, scaling up is not easy, easy or unlikely.” Haim Benaroya at Rutgers University in New Jersey. Challenges include ensuring that the plastic fuselage burns and feeds it to the engine at a constant rate, and testing how burning rocket debris changes its shape and thus its flight path. It is included.

In addition to increasing launch efficiency, autophage engines could also help reduce the problem of space debris, or spacecraft debris that can fly around in orbit and endanger other satellites. There is. Burning out spent fuel tanks, which are typically dropped into the atmosphere or left in orbit, could be a small step toward solving the problem, he said. hugh lewis at the University of Southampton, UK.