"German Scientist's Test Support EM Drive" Topic

Reported in The Telegraph, somewhat breathlessly and misleadingly, but a respected German scientist at the University of Dresden specializing in the testing of testing methods and equipment for anomalous causes of false positives has reported that he has found no such errors or "side effects" in the testing methods used for the "impossible" EM drive, and that his independent tests also consistently produce thrust.

I'll let you google today's Telegraph article, but a preliminary, more thoughtful and knowledgable one appeared in Wired UK earlier this week: link

I want to reiterate the scientist's statement that this test neither confirms nor refutes the claims of thrust for the EM drive, but that he couldn't find any other cause for the thrust in either the testing equipment nor the methodology, and was able to repeat the tests with similar results. As he said, this warrants further study.

While I am one that hopes the EM drive is the real deal, I also recognize the astonishing change in our understanding of physics that must occur if no other explanation for the thrust effect is found. The implications are huge, far beyond soaceflight, and I respect the skeptics. But at this stage, this is not something that can be cast aside merely by the appeal to authority. Yes, so far Newton's Laws have fit the observations and experimentation of four centuries of science; but if a new observation breaks those laws, and does so repeatedly and independently, maybe they aren't the final say on the way the Universe works. Or maybe there's an addendum that slips in sideways.

Or maybe we're all just characters in a 1930s "eccentric inventor builds spaceship in his garage" novel.

link
Starting to sound like Fleischmann and Pons' cold fusion days….

Yes, as the io9 article points out, this study has the exact same issue as the prior studies. The device produces thrust in both the 'on' and 'off' states; which indicates there's no real thrust at all, and it's all an artifact of the test rig.

-Will

Well, it is interesting. And since they are pumping energy (in the form of electricity) into the device it's not like they are getting something for nothing. We shall have to see what happens next.

I agree that it's worthwhile to be skeptical. So, test it and determine the source of the false positives. If thermal energy is a possible cause, then devise a test to reveal this. If you "don't have time to waste on it," then describe what you might do and let interested others give it a shot.
I'm frankly not impressed with the claim that "no one in the field" is interested in this because that claim clearly isn't true. NASA is, at least on some level (yes, on other levels NASA isn't interested, but that's the nature of a political body). The scientists who did the study are interested. As for engineers, they won't be interested unless it's proven to be viable and feasible, at which point they would be. Duh. And engineers are a very conservative bunch. Further, declaring that a paper which has been submitted for peer review won't survive it could read as an attempt to poison the well. Or it could just be an honest response; I don't want to impugn the skeptic.
I have my doubts as well; it just seems to good to be true, and conservation of momentum clearly is the tested and observed understanding we have today. But science is not actually "the answer that is final" but "the answer which works as final unless or until a repeatable, consistent exception is found." And given the simplicity of it all, why not give it a test? At worst, you'll silence breathless pipe dreams and close the sideshow. At best, you'll open new areas of physics and maybe reach the stars. Worth the effort either way, IMHO.

The frustration around the EM-drive stems from the fact that there is ultimately limited time and money available to conduct this sort of research. I'm not surprised that many in the scientific community would prefer the collective effort be expended on something more likely to produce results.

What really needs to happen is that the test rig needs to be torn apart and rebuilt in such a way to eliminate the possible artifacts. But it appears there's no easy way to do this without eliminating the ability to conduct the experiment at all. Which is nearly always a bad sign.

-Will

Is this anything like that high voltage anti-gravity drive from a decade ago? When they finally tested the thing in a vacuum they discovered the so-called anti-gravity was just air flow – ie it didn't work there.

What kind of thermal effect (causing thrust) would you have in a vacuum? I'm confused. Now, a thermal effect in atmosphere I can definitely understand.

Agree that skepticism is required here, but claiming that the test is a failure because of "thermal effect" without explaining how the thermal effect would impact measurements doesn't make sense.

Anyway, hope this stuff pans out and it isn't just because the microwaves are cooking some particles off the metal surface.

Rob

Rob

I remember reading a discussion on the Inertial Propulsion forums from the 1990's (the archives of which have been sadly deleted) where they came up with a simple way to test inertial propulsion devices: Hang it from a wire or rope. If the device generated directional thrust internally, it would move, and the greater the angle of the wire from vertical, the better. Seems the same test could be applied to this EMD (maybe even in a vacuum chamber, if they can find one big enough.)

wminsing 29 Jul 2015 8:50 a.m. PST:

What really needs to happen is that the test rig needs to be torn apart and rebuilt in such a way to eliminate the possible artifacts. But it appears there's no easy way to do this without eliminating the ability to conduct the experiment at all

Apparently, the Dresden team was specifically attempting to "asses possible side-effects in the measurements methods used so far" and they "did find a number of side-effects in the previous setups that indeed can produce large false signals". Their own thrust measurements appear to have been rather conflicting and inconclusive. I'd personally hesitate to say the Dresden paper "supports EMDrive" but to itch his own of course.

For a less charitable way of expressing this, see e.g. Dr. Eashter's writeup:
link

My headline was an attempt to be careful regarding what the linked article states. I don't have access to the actual paper. From your statements, I presume you do. Care to share a link to it? I'm sorry, but I can't give much credence to a blog that has a pile of excrement as its header image; might as well debate a 15 year old. But, I've read the blog and agree that, snide juvenilism aside, it offers valid concerns. (Though some are handwaves, actually.)

As it is, "supports" was chosen to reflect what had been publicly released; namely, the team's statement that: 1. They did detect thrust they couldn't account for in the side effects they tested for, and 2. The EM Drive or at least its current test methods "warrant further study."
Yes, it doesn't confirm, (which is why I used "supports"), but it doesn't refute, either (which is also why I used "supports"), but suggests further study is warranted (thus, "supports"). Honestly, getting a TMP length headline out of this story is a challenge…

Robert Walker blogs in an attempt to strike middle ground between "invetorism" and "scientism" camps:
link

That Walker article is the best (and most thorough) article I've seen posted so far; thanks for the link.

-Will