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[Gord Green]

http://www.nextbigfuture.com/2016/12/china-says-tests-of-propellentless.html

China says tests of Propellentless EMDrive on Tiangong 2 space station were successful.

Dr. Chen Yue, Director of Commercial Satellite Technology for the China Academy of Space Technology (CAST) announced on December 10, 2016 that not only has China successfully tested EmDrives technology in its laboratories, but that a proof-of-concept is currently undergoing zero-g testing in orbit (according to the International Business Times, this test is taking place on the Tiangong 2 space station).

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Scientists with the China Academy of Space Technology claim NASA's results "re-confirm" what they'd already achieved, and have plans to implement it in satellites "as quickly as possible."

"The establishment of an experimental verification platform to complete the milli-level micro thrust measurement test, as well as several years of repeated experiments and investigations into corresponding interference factors, confirm that in this type of thruster, thrust exists."

Cast is a subsidiary of the Chinese Aerospace Science and Technology Corporation (CASC) and the manufacturer of Dong Fang Hong satellites.

According to Li Feng, chief designer of Cast's communication satellite division, the team has built a prototype that so far generates just a few millinewtons of thrust, IBTimes UK reports.

A chinese language paper posted the successful chinese tests of the Emdrive.

Successful propellentless Emdrive is tests in microgravity in space would be conclusive and definitive.

EMdrive could enable constant acceleration and brachistochrone trajectories. Currently emdrive propulsion is still in the millinewton(s) range. However, driving it with more power or finding other ways to scale the propulsion could achieve 0.01g or higher acceleration.

"Impulse" means the spacecraft makes an initial burn then coasts for months, which is a standard rocket mission.



Impulse trajectory I-1 is pretty close to a Hohmann (minimum delta V / maximum time) orbit, but with a slightly higher delta V.

Impulse trajectory I-2 is in-between I-1 and I-3 (it is equivalent to an elliptical orbit from Mercury to Pluto, the biggest elliptical orbit that will fit inside the solar system).

Impulse trajectory I-3 is near the transition between delta V levels for high impulse trajectories and low brachistochrone trajectories (it is a hyperbolic solar escape orbit plus 30 km/s).

Brachistochrone (maximum delta V / minimum time) trajectories are labeled by their level of constant acceleration: 0.01 g, 0.10 g, and 1.0 g.



If you had a ten ton spacecraft. To accelerate at 1 G you need about 100,000 Newtons.

If you had a ten ton spacecraft. To accelerate at 0.01 G you need 1,000 Newtons.

If you had a ten ton spacecraft. To accelerate at 0.0001 G you need 10 Newtons.

With a good nuclear reactor, a high energy consumption Emdrive could be powered for decades.

It would take 100 weeks at 0.01G acceleration to get to 1.95% of light speed.