NASA Engineer Proposes 'Helical Engine' For Interstellar Travel With No Propellant

An engineer who works for NASA has put forward a proposal for a new way to travel through interstellar space—a "helical engine" that could, potentially, push a spacecraft forward without the need for any propellant at all.

David Burns, from NASA's Marshall Space Flight Center, presented his idea on the space agency's Technical Reports Server, which provides access to documents relating to aerospace that were created or funded by NASA, including meetings, journal papers, reports and patents, among others. Burns' research, which he funded himself, is described as an "attempt to define an in-space propulsion engine that does not expend propellant."

He says he is aware of the pitfalls of the work, saying the idea is a thought experiment and even the "basic concept is unproven." However, speaking to New Scientistwhich first reported on his work—Burns said he is prepared for any and all criticism. "If someone says it doesn't work, I'll be the first to say, it was worth a shot," he told the magazine. "You have to be prepared to be embarrassed. It is very difficult to invent something that is new under the sun and actually works."

space travel
Stock photo representing interstellar space travel. Current technology means space travel is expensive, slow and limited. iStock

There are huge engineering challenges relating to space travel. It is very slow—NASA's Voyager and New Horizons would take tens of thousands of years to reach our closest neighbouring star, Alpha Centauri, which sits about four light years away. It's also extremely expensive. It costs SpaceX around $62 million to launch its Falcon 9 rocket, and $90 million for the Falcon Heavy.

Finally, refuelling in space—at the moment—is not an option, so the distance you can travel is somewhat limited.

Many ideas have been put forward about how to build a better spaceship for interstellar travel—notably the EmDrive, which produces thrust with microwaves inside a closed cavity. Tests of this have since suggested the EmDrive would not work.

Burns said his helical engine would work by accelerating ions confined in a loop. By changing their mass slightly, the engine would then move the ions back and forth along the direction of travel to produce thrust. New Scientist notes that the helical engine would need to be 650 feet long and 40 feet wide in order to work.

"This in-space engine could be used for long-term satellite station-keeping without refueling," Burns wrote. "It could also propel spacecraft across interstellar distances, reaching close to the speed of light. The engine has no moving parts other than ions traveling in a vacuum line, trapped inside electric and magnetic fields."

Burns says the research has not been reviewed by experts and that errors relating to his math "may exist." Martin Tajmar, from Germany's Dresden University of Technology, is one of the scientists that carried out tests on the feasibility of the Em Drive. He told New Scientist the helical engine will probably face the same problems the Em Drive did. "All inertial propulsion systems—to my knowledge—never worked in a friction-free environment," he is quoted as saying.