In Brief

Test of 'Impossible' EmDrive Space Engine Passes Peer Review

The EmDrive Space Engine
The EmDrive engine, which is designed to generate thrust by bouncing microwaves around inside a cone-shaped chamber. (Image credit: SPR Ltd./

Good news for all you EmDrive enthusiasts: A new study suggesting that the seemingly impossible space engine may actually work has passed the peer-review process.

The study — which was led by physicist Harold "Sonny" White, of NASA's Johnson Space Center in Houston — found that an EmDrive design generated small amounts of thrust in the lab. These results were leaked online recently, and now the paper has been published, in the American Institute of Aeronautics and Astronautics' Journal of Propulsion and Power.

Development of the EmDrive was begun by British scientist Roger Shawyer about 15 years ago. The engine works by bouncing microwaves around inside a chamber; it requires no propellant and could therefore usher in a new era of superfast and efficient spaceflight, advocates say.

There's just one little issue: The EmDrive shouldn't work, if you put any stock in Newton's Third Law of Motion ("for every action, there is an equal and opposite reaction"). The EmDrive doesn't blast anything out the back, so just how it produces thrust (the equal and opposite reaction) is a mystery.

The new study is just a lab test, and it doesn't prove that the EmDrive definitely works — White and his team couldn't rule out all sources of experimental error, for example — so don't let visions of EmDrive-powered spaceships fill your head. However, its publication is the latest in a series of recent steps suggesting that the technology may be more than a sci-fi dream.

Read more about the EmDrive and the recent lab test here.

Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on

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Mike Wall
Senior Space Writer

Michael Wall is a Senior Space Writer with and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.