(Next Big Future) [http://nextbigfuture.com/2015/07/direct-thrust-measurements-of-emdrive.html?m=1] has been covering the EM drive for a while, and their coverage is science and engineering based not hope and dream. The EM drive isn't for getting to the moon, it's for going beyond the solar system. The EM drive isn't going to do anything for short jaunts. tehstone not all the labs who have tested it have bad reputations which is why this can be considered worth taking a look at. Almost everyone is surprised by the results and trying to figure out where they made a mistake in testing, because it shouldn't work. The comments are usually worth a look at next big future, especially from the user named "goat guy." Goat guy is Next Big's kleinbl00, bringing keen analysis or at least good questions and doubts to the table. Lots of great coverage of military, nuclear, space and biology science and technology at the site.
Saying they work is still a stretch. Several research groups/individuals around the world claim to have had successful tests but all are known for sketchy or flat out fake lab results. This is one of the most exciting tech breakthroughs in a long time if it's real but I'm not getting my hopes up yet.
Apparently there are some issues with this. “This is a direct indication of a thermal effect in reverse (heating versus cooling), which produces a clear false positive thrust signal,” says Davis. “Tajmar has to account for and reconcile this fact as well in his data analysis which he apparently did not discuss in his paper. This would be another nail in the coffin against the existence of any real definite momentum violating thrust produced in the microwave cavity.” Exciting if it's true, but it sounds more likely that they've made a bit of an error.What’s more, when looking at previous EMDrive experiments, Davis noticed that the alleged thrust was generated slowly, and not instantaneously, when the electrical power was switched on.
And the actual paper is behind a paywall. You can read the first page, which basically says "700W magnetron, 20 micronewtons thrust, knife-edge balance and torsion balance in a vacuum, and we get the most output up in the regime where our balance isn't very accurate." I remember all the bullshit hype around Fleischman & Pons and I, too, will remain skeptical for quite some time to come.
I'm not qualified to speak to the science behind this drive but I can mention something about the mathematics it (supposedly) violates. The conservation of momentum is a mathematical model, and one that so far everything appears to follow, much like Euclidean geometry, which held right up until we discovered relativity. However unlike Euclidean geometry or Newtonian physics, which the conservation of momentum is implied within, momentum is still conserved (in a generalised, linear sense) in quantum mechanics and general relativity. Which means one of two things must be the case, either the model no longer applies in this instance, or this does not actually have a closed system the most theorists would assume (this is touched with "it could have something to do with the technology manipulating subatomic particles which constantly pop in and out of existence in empty space." but that is when I'm afraid I must defer to someone with a better understanding of subatomic particles than me)
Something something black magic. I'm not going to be surprised if I never hear about this again.
This is way above my head, but I've been following the topic to the degree I can. It seems that part of the problem is getting funding to properly test it while controlling for confounding factors and that data is slow to come because vacuum chambers tend to eat their electronics and they have to tune the thruster to have a enough thrust to be detected with the facility they hope to use. I vaguely understand there's some strange non-linear stuff going on with the power in and the expected thrust and I think from what's said that the shape or nature of the cavity figures in here somehow. I was trying hard, but that's the best I could do. I may well be very smart, but this takes math and facts and stuff. So I'm frustrated. Because the science reporters explaining this don't really. I mean ... I can handle a few lumps in my pablum. I wish I had the ability to casually throw a few hundred thousand dollars their way in the service of pure curiosity. Never mind what it means for space exploration although that's that's huge if it works. Maybe that's what has everyone scared, because once you are out of the atmosphere - the tech itself doesn't seem to be all that challenging. It's the implications. But back to the testing and finding out if this is real or not, and what the hell is going on. No matter what the outcome, it has to be fundamentally interesting. You don't generally see a chance to resolve interesting questions like that for sums less than fractions of a gross domestic product. So the most confusing thing to me is why they aren't drowning someone in money.
The baseless saga continues <- Link back in time. The baseless saga continues <- Link forward in time.
Enough skeptical people are confounded by the results that it seems worth a closer look, even if it's just to find out why the experimental set ups led us to think it had promise. The reactor isn't all that big, strap one to a satellite and we'd either know the king has no clothes or it's time to get down to some serious work.
It's definitely something unaccounted for in the test setup, I'd love to be the guy who found it. This is now approaching the status of the loose cable at Gran Sasso.
It's an actual prototype. The problem is that no one has a theoretical basis for why it would work, except for some mumbling about virtual particles.
...from which it is still thought to be impossible to extract energy to do work.