Image via SPR Ltd.

It took 50 years, but the mainstream scientific community is finally considering the long-disregarded concept of an “impossible engine” that would revolutionize travel as we know it.

NASA recently confirmed the findings of Satellite Propulsion Research Ltd (SPR Ltd) on the EmDrive space propulsion system. UPi reports the EmDrive uses microwaves instead of an external force, explaining, “the engine musters up a bit of thrust by bouncing microwaves from one end to the other of an unevenly-shaped container, creating a difference in radiation pressure and generating drive.”


Sci-fi fanatics with an eye for history will notice similarities between NASA’s EmDrive developments and the work of Norman Lomer Dean, who introduced the Dean drive in the 1950s. Dean’s eponymous device purported to work without using any propellant, as an engine that appears to ran without being “pushed” by an outside force.

Although it earned a following in sci-fi realms, The Dean drive was ignored by most scientists, in part because it was built upon the premise that Newton’s third law of motion — every action must have an equal and opposite reaction — is incorrect.


However, NASA scientists responded to their “reactionless drive” concluding that the engine “is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma. Future test plans include independent verification and validation at other test facilities.”(Note: ‘quantum vacuum virtual plasma’ appears to be hypothesized, at least in part, by Werner Heisenberg’s uncertainty principle.)

There are great benefits to an engine that violates this particular law of physics, many of them in line with Campbell’s points with the Dean drive. As the SPR team points out, a communication satellite driven by a microwave-powered engine would have a relatively small launch mass. The engine would also extend the lifetime of a satellite, which would no longer be limited by the propellant supply. These innovations would translate into cheaper, more efficient satellite technology. SPR predicts a second-generation engine could help deflect asteroids (a very real concern for NASA) and even revolutionize terrestrial flying: “A future low energy transport infrastructure, no longer dependent on wings and wheels would now seem possible.”

The Verge notes that the EmDrive’s ambitions could be used for long-distance travel, too:
“If the results can be replicated reliably and scaled up — and that’s a big ‘if,’ since NASA only produced them on a very small scale over a two-day period — they could ultimately result in ultra-light weight, ultra fast spacecraft that could carry humans to Mars in weeks instead of months, and to the nearest star system outside our own (Proxima Centurai) in just about 30 years.”

But don’t plan your space vacation just yet. The recent work by SPR only presents the possibility of future testing of an impossible engine, and the results could be flawed: critics pointed out that NASA scientists have replicated faulty results in the past, due to the use of sloppy methods or inaccurate analyses, raising the need for additional testing.

NASA hasn’t offered an explanation of why their experiment worked — just that they think it did. And we’re glad they looked.

Danielle Wiener-Bronner is a news reporter.