NASA: New 'Impossible' Engine Works, Could Change Space Travel Forever


Until yesterday, every physicist was laughing at this engine and its inventor, Roger Shawyer. It's called the EmDrive and everyone said it was impossible because it goes against classical mechanics. But the fact is that the quantum vacuum plasma thruster works and scientists can't explain why.

Shawyer's engine is extremely light and simple. It provides a thrust by "bouncing microwaves around in a closed container." The microwaves are generated using electricity that can be provided by solar energy. No propellant is necessary, which means that this thrusters can work forever unless a hardware failure occurs. If real, this would be a major breakthrough in space propulsion technology.

Obviously, the entire thing sounded preposterous to everyone. In theory, this thing shouldn't work at all. So people laughed and laughed and ignored him. Everyone except a team of Chinese scientists. They built one in 2009 and it worked: They were able to produce 720 millinewton, which is reportedly enough to build a satellite thruster. And still, nobody else believed it.

Now, American scientist Guido Fetta and a team at NASA Eagleworks — the advanced propulsion skunkworks led by Dr Harold "Sonny" White at the Johnson Space Center — have published a new paper that demonstrates that a similar engine working on the same principles does indeed produce thrust. Their model, however, produces much less thrust — just 30 to 50 micronewtons. But it works, which is amazing on its own. They haven't explained why their engine works, but it does work:

Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, 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.

The entire idea that we have found something that seems to go against the the principle of conservation of momentum just seems crazy to me. But the fact that it has worked for two independent parties can't be denied. That's the laboratory speaking. Then again, perhaps both labs made a mistake. I'm sure this will be tested by the Russians and the Europeans too, but at least I'm glad we are working on it.

But the fact that we may be witnessing something completely new, something that may push us forward into sci-fi territory once again, is very exciting.


    When you say 'no one believed' it, are you talking about Americans? Because thanks to the concept of American Exceptionalism that you guys seem to love ever so, Yanks have a hard time believing that other nations can develop anything, especially when it's a competitor like China.

      No, pretty much no one in the world believed this would work because of violation of conservation of momentum. It was invented in the UK and no one there wanted to build it. Chinese team built it and published results, although no one believed that either. And NASA confirmed it just recently, and now everyone has gone berserk over it. No one know how it works either. See entry on wikipedia:

      Also, it moves in the direction of the bigger side of the conical shape, to the right, in the above picture.

      Last edited 02/08/14 5:43 pm

        Indeed! Not to mention that in science disbelief is a very good thing! Everything is false until its been proven right a bunch of times by different people at 5 sigma.

        They were right to be sceptical. Crackpot inventors regularly throw out machines that claim to violate well-established principles, and none of them stand up to scrutiny. Scientists have better ways to spend their time. Conservation of Momentum is not a law that is discarded lightly, and extraordinary claims require extraordinary evidence.

        That said, big props to Shawyer, who persisted with developing not only his theories but his demonstrators, systematically eliminating possible sources of error until other scientists ran out of objections and tried actually replicating his results (good to see the Chinese taking the odd long shot too). It's still not certain that this is a real effect, but enough evidence and attention has accumulated that it will be more thoroughly investigated. And if it continues to hold up, it will be revolutionary indeed.

        It's worth also noting that, although Fetta's Cannae variant produces relatively tiny thrust, that's still enough to be very useful, and the stronger EmDrive that the Chinese built would be sufficient to keep the whole ISS in orbit. And Shawyer claims that his theories show the theoretical thrust possible by a superconducting resonant cavity could be as high as 30 kN/kW - enough to lift a small car!

          30kN/kW is an impossible thrust:power ratio, it violates the conservation of energy, not just momentum. 1000J/s cannot possibly lift a car under earth's gravity, it just violates the conservation of energy.

      I like more the fact they didn't examine or rebuild the Chinese angine and had to go build their own that produced less thrust, but I suppose you cannot produce your own paper and research or patented object the other much for collaborating to go forwards with science...

      Last edited 02/08/14 6:35 pm

        I'd say coming to the same result via different methods is very promising for science!

    Well if no one knows how it works at the moment, perhaps it might be 'perpetual motion' (insert appropriate words here).

      It still requires energy input. It's not "perpetual motion".

      The reason they are making a big deal about it, is that every engine that goes to space for satellites and rockets, etc. needs a propellant fuel that inevitably runs out. With this engine they can send them up with just solar panels and use the thrusters indefinitely.

    This is a non-article at the moment. NASA also designed a disabled version of the device that shouldn't have produced any thrust at all, but measured small thrust there as well. There's clearly an interaction outside of the experimental scope happening. More research is necessary, this is far too early to be reporting on.

      Anything to do with thrusting i'm interested in.

      Going by the Wikipedia article, the "disabled" device you are referring might be for a different test - the Cannae drive, which was incorrectly labeled as disabled by the media, but actually just configured in a different way to test a certain hypothesis (in a way that if the hypothesis was correct, it would not produce thrust).

      It wasn't "disabled". The "null" test rig had the exact same drive but lacked the slots in the bottom that Fetta claimed were needed. NASA themselves concluded that this result supports the hypothesis that the drive simply does not need the slots to operate (the EmDrive has no slots either).

      It's not yet obvious what's going on. More study is warranted.

        @positivist and namarrgon

        I've seen this mentioned on Wikipedia, but it doesn't match my reading of the paper. Can either of you point to the page and paragraph where this is stated?

          If I could find the full paper that Wikipedia refers to, I might be able to help you, but I can only dig up the single-page Lay Summary.

    So piezoelectric effect...

    Cue mysterious disappearances unmentioned in mass media.

    So "scientists can't explain why" the engine works, but surely the inventor must know. Why would anyone to consider building it if Roger hadn't developed a plausible theory around the principle behind it.

    I'll ask him and let you know what he says.

      It is all on his site, the easiest to read paper is here:

    I must be missing the point cause it doesn't seem implausible to me. Solar panels make electricity, electricity makes microwaves, microwaves can only escape in one direction to produce a thrust.

      The microwaves are bouncing around an enclosed space, so the net thrust would be expected to be zero. A bit like rowing in a boat by pushing the oars in alternate directions.

      Also, the thrust generated is enormously more than would be expected from a photon drive. You need a LOT of power to get usable thrust from a photon drive.

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