It takes advantage of a loophole in Einsteinian physics.
New Scientist is reporting that NASA engineer David Burns is making some bold claims about a conceptual new spaceship thruster he calls the "helical engine" — a concept the magazine admits "may violate the laws of physics."
"The engine itself would be able to get to 99 per cent the speed of light if you had enough time and power," Burns told New Scientist.
The engine, described in a recent paper Burns posted to a NASA server, takes advantage of a weird glitch in Einsteinian physics.
By accelerating a loop of ions to nearly light speed and then manipulating their velocity — and hence, because of the laws of relativity, their mass — the engine achieves the ultimate space travel free lunch: forward thrust without shooting anything out behind.
Even if the engine works in practice, it'll have other disadvantages. According to New Scientist, a helical engine that was 200 meters long would generate about as much force as typing on a keyboard — so, while Burns may be right that it could accelerate to near-light speed, it would take a very long time.
"I’m comfortable with throwing it out there," Burns told the magazine. "If someone says it doesn’t work, I’ll be the first to say, it was worth a shot."
READ MORE: NASA engineer's 'helical engine' may violate the laws of physics [New Scientist]
More on light speed: Physicists Have a New Idea for Faster-Than-Light Travel