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Comment by tribaal | Hacker News Reader

So, it seems from reading the paper's abstract that they did measure thrust both from the real propulsion test device and from the dummy test device. That's not very promising:

http://ntrs.nasa.gov/search.jsp?R=20140006052

> Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article).

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I'm not as certain. They don't mention measuring thrust from when they replace the test article with an RF load (whatever that means), or when they reverse the test article. Then they end on this note: "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. Future test plans include independent verification and validation at other test facilities."

So that makes me think that maybe they just don't know why it works, so the modified one still works for the same unknown reason. Probably not though. Like they say, they need more tests.

And they did the experiments in a vacuum chamber but at atmospheric pressure so that I can easily imagine that they just accelerated polar molecules or something like that.

Yes, or maybe something like a plasma actuator.

Meh. If that's true then Wired shamelessly went for click bait. :P

Well, I'd love to be wrong really.

Pretty please, somebody confirm my reading comprehension skills are complete garbage? :)

It doesn't say how much thrust the null article "produced." If there's a significant difference, that's still very suggestive.

My next suspects for error would be that the device is propelling itself through heat dissipation or electrostatic ally by throwing off charged particles. Both of those possible confounding factors are testable, either by measuring heat via IR imaging and computing what propellant effect that heat would have of by dummying up the null device to produce and dissipate an identical amount of energy to the non-null device.

But honestly, I'm a hacker. I'd go rent me a vacuum chamber and put it on a whirlygig and see if it makes it spin. If it spins faster and faster and faster until it flies apart (well okay maybe I'd turn it off before loss of structural integrity), something is definitely off in our understanding of physics and God really will let us have hoverboards. So give me a hoverboard.

if the drive is propelling something to get tens of µN, you could float strips of thin plastic film across the supposed path of reaction matter and it'd be visibly accelerated by collisions with that something, at least if my math is right.

Would have been nice if the scientists didn't know which device they were testing - blind.

In the majority of physical experiments doing a blind test is not that helpful, since it will not change the physical data. It can happen that blind testing is helpful, but most of the time it is a sign that the protocol or equipment needs to improved.

Most of the time bias creeps in at the analysis stage. In my experience. Deciding what data to keep and what to reject, deciding which fitting algorithm is working correctly, etc.

The purpose of blind testing in medicine is to eliminate the possible effects caused by different patient-doctor psychological interactions.

If we find out that inanimate objects behave differently if the operator does/doesn't believe in their success (as patients do), then that'd be much bigger news than engine development.

Blind testing is still very important in physics; go look up N-rays.

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