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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 tng on 2/9/2013 3:35:16 PM , Rating: 1
Research into Cold Fusion continues in private and government facilities and there is progress being made.

Part of the original "Cold Fusion" issue was as the poster above mentioned, was that the original experiment was not detailed throughly enough in the paper that was published. This led to many different experiments many of which had negative results.

They have conferences on this now, although it is not called "Cold Fusion" anymore for obvious reasons.


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.


RE: Interesting...keep moving forward
By Shadowself on 2/10/2013 6:35:14 PM , Rating: 4
quote:
Research into Cold Fusion continues in private and government facilities and there is progress being made.
What progress? Have they made even a single model that works 100% of the time always giving positive net energy out -- or can be "started and stopped under the experimenter's direct control" always with positive energy out? Not that I've ever heard been aware.

I was at the University of Utah when this broke (doing work on a different set of nuclear experiments in the physics department). [[Hey, sometimes it takes going out to a backwater area of the world to do certain research!]] I knew the physicists that broke away from their own research to help Ponds and Fleishman properly implement experiments and eliminate external sources of error to prove it out. A couple of them were friends of mine. I was involved in a couple of conferences about it. Several organizations put a lot of money into it -- including the State of Utah. They spent several 10s of millions trying to prove it true. Everyone -- yes, everyone -- involved wanted it to prove out. It was going to change the world.

However, it was not just badly documented. The two "nuclear chemists" didn't even know how to properly measure total energy output (the real data point) versus transient power output as a function of transient power input (something that can easily fake you out and appear to give you results that are not real).

Sure there are a few labs still chasing this, but no one I know has seen any concrete evidence that "Cold Fusion" gives any net energy output over time. Not one single experiment.

And before you bring it up, Muon based fusion can work (and has been shown to work) at "room temperature". While this does work, it has no where near a positive energy outcome as the energy to create the base particles requires much, much more energy than you get out the each fusion.


RE: Interesting...keep moving forward
By tng on 2/10/2013 11:43:46 PM , Rating: 2
quote:
What progress?
Just what I have heard from better minds than mine...

Despite all that you have said, there is still money being put into this and has been since the original experiment. I will assume that someone sees some potential in it.


RE: Interesting...keep moving forward
By Shadowself on 2/11/2013 4:50:28 PM , Rating: 2
quote:
Despite all that you have said, there is still money being put into this and has been since the original experiment. I will assume that someone sees some potential in it.
Some people still put money into the Flat Earth Society too.


RE: Interesting...keep moving forward
By tng on 2/11/2013 10:28:53 PM , Rating: 2
While I have my doubts as well, I am reminded about scientists quoted in a NY Times article from the mid 1800's saying that no human could survive at a speed of 60MPH (the speed of a new train engine that was being introduced).


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