This story from a Wired article: NASA is a major player in space science, so when a team from the agency this week presents evidence that "impossible" microwave thrusters seem to work, something strange is definitely going on. Either the results are completely wrong, or Nasa has confirmed a major breakthrough in space propulsion.
British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems, but critics reject his relativity-based theory and insist that, according to the law of conservation of momentum, it cannot work.
NASA states... "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"
(Score: 3, Insightful) by wonkey_monkey on Friday August 01 2014, @09:52PM
Two things are of note, as best as I have gathered as this story unfolds:
Firstly, NASA tested two devices. One was the working device, the other was a device deliberately changed so as not to produce thrust. The problem is, they detected the same amount of thrust from both devices.
Secondly, the test wasn't done in a vacuum. As I recall, there was a similar brief debacle when everyone was clamouring that lifters [wikipedia.org] were anti-gravity devices, because they'd been tested in a vacuum - the problem there was that the vacuum wasn't hard enough. Once you expelled all the air, they failed to function.
This test wasn't even done in a partial vacuum, as I understand it.
systemd is Roko's Basilisk
(Score: 3, Informative) by DrMag on Saturday August 02 2014, @03:11PM
I have seen others offer a quote from the paper:
The full paper is here [aiaa.org], but I don't have access to it from where I am now. I'll have to verify the quote when I get back to work next week. I think the confusion is from the abstract [nasa.gov], which states that they did a test at ambient pressure, but says nothing about the other test configurations. I may certainly be wrong, but I doubt that a NASA team would fail to test this in vacuum before presenting like this.
(Score: 2) by DrMag on Monday August 04 2014, @02:19PM
Ok, now that I'm at work I've had a chance to read through the paper. The quote is valid, though to be fair it is in the description of the vacuum chamber capabilities, which is not necessarily the same as the setup used in the test. However, nothing in the paper suggests they did not, so either it's a gross omission, or they did tests at vacuum.
In either case, they are planning a new design that they expect to be an order of magnitude better (0.1 N per kW), with an added feature to rule out another possibility I hadn't remembered to consider: