NASA has been testing new space travel technologies throughout its entire history, but the results of its latest experiment may be the most exciting yet — if they hold up. Earlier this week at a conference in Cleveland, Ohio, scientists with NASA's Eagleworks Laboratories in Houston, Texas, presented a paper indicating they had achieved a small amount of thrust from a container that had no traditional fuels, only microwaves, bouncing around inside it. 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.
The type of container NASA tested was based on a model for a new space engine that doesn't use weighty liquid propellant or nuclear reactors, called a Cannae Drive. The idea is that microwaves bouncing from end-to-end of a specially designed, unevenly-shaped container can create a difference in radiation pressure, causing thrust to be exerted toward the larger end of the container. A similar type of technology called an EmDrive has been demonstrated to work in small scale trials by Chinese and Argentine scientists.
While the amount of thrust generated in these NASA's tests was lower than previous trials — between 30 and 50 micronewtons, way less than even the weight of an iPhone, as Nova points out — the fact that any thrust whatsoever is generated without an onboard source of fuel seems to violate the conservation of momentum, a bedrock in the laws of physics.
"not attributable to any classical electromagnetic phenomenon."
Most impressively, the NASA team specifically built two Cannae Drives, including one that was designed to fail, and instead it worked. As the scientists write in their paper abstract: "thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust." That suggests the drive is "producing a force that is not attributable to any classical electromagnetic phenomenon," the scientists write. It may instead be interacting with the quantum vacuum — the lowest energetic state possible — but the scientists don't have much evidence to support this idea yet.
There are many reasons to be skeptical: the inventor of the Cannae Drive, Guido Fetta, has only a Bachelor’s Degree in Chemical Engineering and is operating his company Cannae as a for-profit venture. Still, the fact that such results were produced by NASA scientists is promising and should warrant further investigation.