Sorry, The EMDrive Still Isn’t “Confirmed” | Vol. 3 / No. 1.4

Shawyer's EMDrive prototype | Photo: Mario Solera, CC BY 2.0
Shawyer’s EMDrive prototype | Photo: Mario Solera, CC BY 2.0

Have they “confirmed” NASA’s impossible drive? …no. But read on to find out what they have done.


So it’s come around again. The last time we saw it was in July: the EMDrive, “NASA’s impossible engine” which “generates thrust without propellant.” The one that will get us to the moon in four hours instead of a few days. The one that violates basic conservation of momentum.

Back in July everyone hyped it up and then realized that, as scientists and skeptics alike pointed out, it was probably “still bullshit.” Really what it comes down to is that it’s more likely to be an artifact of thermal expansion or interactions with the Earth’s magnetic field than any actual thrust.

So why is it back in the news? Why are headlines reporting that “NASA Confirms that the ‘Impossible EMDrive Thruster Really Works“?

Well, there’s apparently an embargo on the actual data from the latest round of experiments, so we’re not totally sure yet, but according to scientist Paul March (username Star-Drive over at the NASA spaceflight forum), they still haven’t been able to figure out where the thrust they’ve been measuring is actually coming from.

At this point I need to remind you that “not knowing where the error is” is not “proof there is no error.” March knows this, you know this, I know this, but not everyone knows this, so I have to say it.

Nevertheless, after doing their best to eliminate the noise resulting from interactions with the Earth’s magnetic field, March reports: “we are still seeing over 100μN of force with 80W of RF power going into the frustum running in the TM212 resonant mode,” which is to say, they’ve corrected for it as best they think they can and they’re still detecting (tiny, tiny amounts of) thrust.

He maintains that these thrust signatures are still “contaminated” by thermal expansion, and adds that it gets much worse in a vacuum because of vacuum’s insulating power, which means that “the in-vacuum thrust runs look very thermally contaminated whereas the in-air runs look very impulsive.

This is to say that at present, they think they’ve taken care of the magnetic field stuff, but the data from thermal forces is still muddying up their readings. This does not mean they have a “confirmed” EMDrive. But it does mean they’ve eliminated one of the possible sources of the “anomalous thrust signals” they’re reading.

But have they given up? Nope. They want to know where the thrust signals are coming from, so they’re getting ready for another series of tests to try to distinguish between the thrust they know they should be getting from the thermal effects and what they’re measuring.

And this is what I really love about this whole EMDrive saga. It isn’t that they’ve invented a “warp drive” or broken conventional physics (as exciting as that would be). It’s that these guys are getting coverage for performing one of my favourite kinds of science: proving things don’t work. Negative results aren’t often considered publishable data, so we end up with a lot of repeat experiments and lost results, because the results weren’t a groundbreaking new discovery. And good luck getting a headline out of it.

But these guys are trying to prove something supposedly amazing is just something mundane, and people are actually forced to follow along just in case they can’t do it. The nearly infinitesimal chance they’ve discovered “new physics” by bouncing microwaves around inside a metal box is exciting enough to make proving nothing’s going on interesting.

So I look forward to their experiments’ day in peer review, and to their discovery of what exactly is generating the anomalous readings. Do I think it’s going to be a new kind of starship engine? Not really, no. But is it a great example of science in action? Sure seems that way.

You can read more of the thread over at NASA Spaceflight forums.


Richard Ford Burley is a writer and doctoral candidate at Boston College, as well as an editor at Ledger, the first academic journal devoted to Bitcoin and other cryptocurrencies. In his spare time he writes about science, skepticism, feminism, and techno-futurism here at This Week In Tomorrow.


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