This is big if true:
The “reactionless” Electromagnetic Drive, or EmDrive for short, is an engine propelled solely by electromagnetic radiation confined in a microwave cavity. Such an engine would violate the law of conservation of momentum by generating mechanical action without exchanging matter. …
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).
EmDrives are ideal for deep space exploration, since they remove the need for refueling—or even the weight and space needed to store fuel—thus simplifying logistics and design. In theory, all one would need for an EmDrive would be a power source, like solar energy or a reactor, to fuel anything ranging from a manned Martian mission to robotic probes going outside of the solar system. EmDrives would also result in smaller and more efficient satellites, since they could ditch space-consuming chemical thrusters used for maneuvering.
This article has more. Given the prevalence of fake science in China, I would take this announcement with a grain of salt – even more so given the dubious nature of the technology itself, which apparently defies the known laws of physics.
NASA last month published a peer-reviewed paper claiming it had successfully tested a working EmDrive on the ground.