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from the Would-an-EnDrive-be-half-as-wide? dept.
The man behind the disputed thruster technology EmDrive has published a presentation detailing the third generation of the device. Roger Shawyer envisions EmDrive 3.0 enabling personal flying vehicles and a "space elevator without cables":
[Although] the second generation of the EmDrive can theoretically produce 3 tonnes of thrust for 1 kilowatt of power, it isn't able to move very far, so it is only useful for marine applications or for diverting asteroids, like in the new CBS sci-fi TV drama Salvation.
Shawyer has long said that his aim for inventing the EmDrive was to help get satellites into space cheaply, to enable more applications and new ways for the human race to combat global warming and the energy crisis. Essentially, the EmDrive needs to be able to move and work as well as a conventional rocket, in order to be a viable solution.
To negate these shortfalls, Shawyer's firm Satellite Propulsion Research Ltd (SPR) has also been researching a third generation of the EmDrive, which solved the acceleration problem by reducing the specific thrust.
So instead of getting 3 tonnes of thrust for every kilowatt, substantially less thrust is produced – but it can be used to accelerate the device (more about this theory can be read in a paper Shawyer presented in Beijing in 2013).
Speaking of that TV show, Roger would like some credit please.
Related UK patent application. Also at Next Big Future.
Previously: Finnish Physicist Says EmDrive Device Does Have an Exhaust
It's Official: NASA's Peer-Reviewed EmDrive Paper Has Finally Been Published
Space Race 2.0: China May Already be Testing an EmDrive in Orbit
Physicist Uses "Quantised Inertia" to Explain Both EmDrive and Galaxy Rotation
(Score: 0) by Anonymous Coward on Sunday August 13 2017, @05:50AM (3 children)
Conservation of momentum is a much more straight forward objection. Energy conversation gets very slippery, but momentum is pretty simple. In any case the EM drive seems to directly violate this. This isn't a new discovery. Like you're mentioning here if it does work as it seems to work, one of the many revolutionary results would be infinite energy production. There is a paper [arxiv.org] on this exact topic.
This is the reason that the engine is so controversial. It should not work. In every test we have been able to throw at it (including NASA contracting out 3 independent wings to develop/test their own drives) indicates that it is working. This is likely now the reason that it's seemingly being kept secretive. If, somehow, this device works it would be the most revolutionary discovery in the history of humanity. I tend to remain cynical as well. However, at this point that cynicism is only because I refuse to let myself start drooling at the potential. All evidence and testing to date indicates that it's justified to begin drooling, at least a little bit.
(Score: 1) by khallow on Sunday August 13 2017, @11:59AM (2 children)
Energy/momentum conservation is not something you trivially violate (and sorry, but this is a trivial extension of a century of EM experiments). We have never seen an example of such a violation while we have seen a lot of examples of scientific mistakes. There might be a real effect here, but it will most likely obey the laws of physics just like everything else we have ever seen does. Which is why I'm leaning towards photonic/ion propulsion as the actual mechanism behind the drive.
(Score: 0) by Anonymous Coward on Sunday August 13 2017, @04:32PM (1 child)
You can't say photonic / ionic, those are two very different things. And yes, the em drive is photonic, that was the whole point. Also, it doesn't violate conservation of momentum, the momentum comes from pure energy (photons) transferred into mass momentum.
(Score: 1) by khallow on Monday August 14 2017, @03:50AM
But two very different things that can be generated by the EM drive simultaneously. It could be both emitting microwave photons and ionizing and ejecting atoms from the surface of the device.
No, that isn't. An LED would make for a more efficient photonic drive. And of course, if you have an external light source, say like the Sun, you can double the photonic thrust from the Sun by using a mirror.
Even if that is true, and I'm not saying it is, you still have the problem that it violates other laws of physics for which we've never seen a violation. The flaws are in what is inconsistent with our other observations of reality not in what is consistent.
And sorry, I don't buy that microwaves in a box creates exotic new physics with massive potential to break conservation of energy.