Pages

September 24, 2008

China Will Build Controversial Emdrive, experimental system should be ready by end of 2008


Wired reports that China will build the Controversial Emdrive.

UPDATE: The cost and details of superconducting radiofrequency cavities is examined and the potential if the emdrive works
END UPDATE

This site has covered the Emdrive several times before, including the controversy, and the upside. A successful superconducting system would be most efficient at nulling out gravity (3 tons of lift per kilowatt).

Satellite Propulsion Research Ltd. (SPR), has constructed demonstration engines which he says produce thrust, using a tapering resonant cavity filled with microwaves. Roger Shawyer, the originator of the drive, is a scientist who has worked with radar and communication systems and was a program manager at European space company EADS Astrium; his work rests entirely on Einstein being right.

"NPU [Northwestern Polytechnical University] started their research program in June 2007, under the supervision of Professor Yang Juan. They have independently developed a mathematical simulation which shows unequivocally that a net force can be produced from a simple resonant tapered cavity," Shawyer tells DANGER ROOM. "The thrust levels predicted by this simulation are similar to those resulting from the SPR design software, and the SPR test results." NPU is "currently manufacturing" a "thruster" based on this theoretical work.

"I could confirm that our mathematical simulation gives the results Dr. Roger Shawyer told you. Now we are submitting our result to a journal. It is now under the consideration of the editor," Professor Yang adds. "We also developed a tapered cavity and are preparing an experiment which will be completed at the end of this year."

Independent confirmation would be a big deal -- though many will want to see it published in a peer-reviewed journal. Prof. Yang has plenty of experience in this type of area, having previously done work on microwave plasma thrusters, which use a resonant cavity to accelerate a plasma jet for propulsion. While the theory behind the Emdrive is very different, the engineering principles of building the hardware are similar. The Chinese should be well capable of determining whether the thruster really works or whether the apparent forces are caused by experimental errors.

Shawyer compares a C-Band Emdrive with the existing NSTAR ion thruster used by NASA. The Emdrive produces 85 mN of thrust compared to 92 for the NSTAR (that's about one-third of an ounce). But the Emdrive only consumes a quarter of the amount of power and weighs less than seven kilos compared to over thirty kilos. But the biggest difference is in propellant: NSTAR uses ten grams per hour – the Emdrive uses none. As long as it has an electricity supply, the Emdrive will keep going.

Shawyer calculates that a solar-powered Emdrive could take a manned mission to Mars in 41 days. Provided it works, of course.


A flight ready thruster is planned for May 2009






Superconducting second generation EM drive
A second generation version of the engine (if it works) would generate specific thrust of 0.93 Tonne / kW.

Hybrid Engine using Emdrive to counter gravity
Another way to limit the kinetic output is to use the technology in a lift engine where the high specific thrust is used only to counteract gravity. Any acceleration of the vehicle itself would be by conventional propulsion.

Changing earthbased transportation
Typically 3 tonnes of lift could be obtained from 1kW of microwave power. A future low energy transport infrastructure, no longer dependent on wings and wheels would seem possible.

Emdrive Presentation at Space 08 conference


Key points from the slideshow: The chinese are making a S-band prototype engine. There is an version 1.5 superconducting system with Q 6*10**6 which would have 100 times more thrust than the version 1 system. This would be 32 Newtons of static thrust. One thousand times less than the version 2 superconducting system that would equal the best current superconducting Q of 5*10**9. If these systems are working then the sizes of the forces involved should be unambiguous. Not tiny millinewton forces which could be from mistakes or other causes but larger forces.

FURTHER READING
This site covered the Emdrive two years ago in 2006

Near term benefits of the emdrive at the SPR site.
blog comments powered by Disqus