Controversial Propellentless EmDrive is said to be undergoing tests in
space on the Tiangong-2 station and US Air Force X-37B plane:

"IBTimes UK has been informed that the US Air Force is currently testing out a
version of the EmDrive electromagnetic microwave thruster on the X-37B unmanned
military space plane, while the Chinese government has made sure to include the
EmDrive on its orbital space laboratory Tiangong-2."

See:

http://www.nextbigfuture.com/2016/11...mdrive-is.html