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EmDrive  (Source: emdrive.com)
It's a a propellantless microwave thruster that defies Newton's laws of motion

Chinese scientists have taken on a heavily criticized space drive idea that could one day launch satellites, deep space probes and even flying cars.

The research team hails from Northwestern Polytechnic University in Xi'an, and was led by Yang Juan. What they developed was a propellantless microwave thruster called EmDrive, which is a controversial idea because it goes against Newton's laws of motion -- and many have claimed to create a "propellantless" thruster before and failed.

Newton's laws of motion are all based on the idea that firing propellant out of the back at a high speed will push a craft forward. While solar cells offer infinite power, thrust is limited by propellant. Many have tried to get around this, but several scams have made this particular field a joke in the scientific world.

While space drives tend to rely on Newton's laws of motion, the EmDrive is a closed, conical container that has a net thrust toward the wide end when filled with resonating microwaves. This goes against Newton, who said that no closed system could have a net thrust. However, EmDrive works because the microwaves have a group velocity (the speed of a collection of electromagnetic waves) that is greater in one direction than the other -- which is where Albert Einstein's theory of relativity comes in.

British engineer Robert Shaywer, who began looking at the concept of a propellantless thruster when he opened his own company called Satellite Propulsion Research in 2001, is the original creator of the EmDrive. He made demonstration thrusters to prove it could be done, and even made sure the test results were accurate (meaning, the results weren't affected by friction, ionization, air currents, electromagnetic effects or interference). The first, made in 2003, had a thrust of 16 mN. This was enough to show it could be done.

However, he received a ton of criticism for his idea and was ridiculed in his own country. But the Chinese team at Northwestern Polytechnic University believed in his research and took the project head on to author the latest study, "Net Thrust Measurement of Propellantless Microwave Thruster."

The Northwestern Polytechnic University team was able to create the EmDrive with 720 mN of thrust with a couple of kilowatts of power.

So what purpose does EmDrive have? It could halve launch costs of satellites because as much as half the launch weight of these objects are attributed to propellant.

Shawyer is even working on a superconducting thruster that could be ready as soon as 2016. It would boost the Q value of the cavity, which determines the amount of thrust produced. He said it could be boosted by a factor of several thousand, possibly equating to a tonne of thrust per kilowatt of power.

Source: Wired



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RE: Interesting...keep moving forward
By JediJeb on 2/9/2013 7:04:53 PM , Rating: 2
I never understood how cold fusion was supposed to generate energy. If it does not produce heat then what energy did it produce? I seem to remember back then that the experiment showed Helium being produced at room temperature from supposedly fusing Hydrogen, but it took energy to make the reaction go, and seemed to me to be net negative on energy production.


RE: Interesting...keep moving forward
By Jackthegreen on 2/9/2013 9:37:16 PM , Rating: 3
The term "cold fusion" is meant to be about the initial state of the reactants. Normally fusion requires very hot temperatures, but the idea behind cold fusion is to try and get self-sustaining fusion to happen at more realistic temperatures like where water is a liquid under normal pressures. Once fusion has occurred the reactants do increase in temperature since that's how the released energy manifests. Some methods already exist, but they don't end up being energy-positive, hence why research continues.


By Shadowself on 2/10/2013 7:01:01 PM , Rating: 4
quote:
The term "cold fusion" is meant to be about the initial state of the reactants.
Not quite. "Cold Fusion" simply means you don't have to get the initial reactants into a plasma state before fusion can occur. The concept of "Cold Fusion" is that the nuclei fuse without having to be forced together under extreme temperature and pressure while in a plasma state. The concept is that the lattice nature itself combined with the specific atoms supposedly being fused set up a state that EM repulsion is overcome and the strong and color forces take over -- resulting in the nuclei being fused.

quote:
Once fusion has occurred the reactants do increase in temperature since that's how the released energy manifests.
Again, not quite. The "temperature" of the reactants in "Cold Fusion" is not the underlying issue. The question is how that gets transferred to the lattice. In most theories the resulting elements (the reactants are gone!) radiate their energy away to the crystal lattice in which they are held. The radiation is a combination of X- and Gamma-rays. Very little is radiated away as "phonons" or "virtual thermal particles", if you will. In most theories not much is transferred through motion of the particles and direct lattice collisions.

But then again, it's pretty much a useless discussion as no one has shown "Cold Fusion" to really, undeniably work.


By Reclaimer77 on 2/10/2013 6:29:44 PM , Rating: 2
quote:
I never understood how cold fusion was supposed to generate energy.


That's because you aren't one of the greatest scientific minds of our time, Keanu Reeves

http://davelozo.files.wordpress.com/2010/07/keanu....

Here he is now, making Cold Fusion a reality in the mid 1990's.


"I'd be pissed too, but you didn't have to go all Minority Report on his ass!" -- Jon Stewart on police raiding Gizmodo editor Jason Chen's home














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