The 'impossible' EmDrive could reach Pluto in 18 months?
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Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#2"WIRED understands that there are multiple labs around the world working on their own EmDrives, although Tajmar's is the only new one willing to go public so far."
I'm very curious about this bit. I wonder who is working on it?
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#3I wonder how they rule out the effects of the Earth's magnetic field. I can see there being some small effect due to some kind of eddy currents pushing ions into one direction. Maybe they turn the apparatus at multiple angles and check the bias to north-south?
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#4Has any independent laboratory confirmed this effect and published on it in a peer-reviewed journal?
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#5"WIRED understands that there are multiple labs around the world working on their own EmDrives, although Tajmar's is the only new one willing to go public so far." I'm very curious about this bit. I wonder who is working on it?
NASA has a group working on it: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2014000...
The Northwestern Polytechnical University in China is testing a version of the EmDrive: https://dx.doi.org/10.1088%2F1674-1056%2F22%2F5%2F050301
Finally, a number of amateurs are interested as well: http://emdrive.wiki/Building
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#6Has any independent laboratory confirmed this effect and published on it in a peer-reviewed journal?
"Roger Shawyer is encouraged by Tajmar's work, which he says validates his own theoretical predictions as well as his experimental results. Shawyer has often been dismissed because of his own lack of peer-reviewed scientific publications. That looks to be changing very soon; a paper Shawyer presented at the International Astronautical Conference in Toronto in 2014 is in the final stages for peer-review for publication. This describes an advanced EmDrive-powered spaceplane."
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#7It's good to see that someone finally got around to testing this in a vacuum. Here's the paper mentioned in this story:
http://arc.aiaa.org/doi/abs/10.2514/6.2015-4083
High levels of skepticism are still warranted, as much as I would love for this to pan out. Every time this gets tested—presumably more and more carefully—the measured force gets smaller. The original test at Chinese Northwestern Polytechnical University measured 720 mN; this latest test in a vacuum chamber, only 20 μN. This is so tiny that a test anomaly would seem a much more plausible explanation than a violation of the conservation of momentum.
Of course the ultimate test would be to put one of these in space and try accelerating something with it, in the same way that the ultimate test of a perpetual motion machine would be to make one perform macro-scale net work.
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#8Let's cut to the chase:
5. Q. Why does the EmDrive not contravene the conservation of momentum when it operates in free space?
A. The EmDrive cannot violate the conservation of momentum. The electromagnetic wave momentum is built up in the resonating cavity, and is transferred to the end walls upon reflection. The momentum gained by the EmDrive plus the momentum lost by the electromagnetic wave equals zero. The direction and acceleration that is measured, when the EmDrive is tested on a dynamic test rig, comply with Newtons laws and confirm that the law of conservation of momentum is satisfied.
So, the momentum simply "builds up". That's an exceptionally weak explanation.
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#9It's good to see that someone finally got around to testing this in a vacuum. Here's the paper mentioned in this story: http://arc.aiaa.org/doi/abs/10.2514/6.2015-4083 High levels of skepticism are still warranted, as much as I would love for this to pan out. Every time this gets tested—presumably more and more carefully—the measured force gets smaller. The original test at Chinese Northwestern Polytechnical Universi…
From the abstract: "We identified the magnetic interaction of the power feeding lines going to and from the liquid metal contacts as the most important possible side-effect that is not characterized yet. Our test campaign cannot confirm or refute the claims of the EMDrive..."
Given that this is a 700W microwave oven putting out a tiny amount of thrust, and that a positive finding would invalidate a basic conservation law, my money is on those wires.
Re: The 'impossible' EmDrive could reach Pluto in 18 months?
#10Has any independent laboratory confirmed this effect and published on it in a peer-reviewed journal?
"Roger Shawyer is encouraged by Tajmar's work, which he says validates his own theoretical predictions as well as his experimental results. Shawyer has often been dismissed because of his own lack of peer-reviewed scientific publications. That looks to be changing very soon; a paper Shawyer presented at the International Astronautical Conference in Toronto in 2014 is in the final stages for peer-review for publicatio…
You're referring to an unpublished paper by the author, which appears to be a design for a space vehicle. I asked about independent tests of the claimed effect.