New research seems to point to probable systematic error for the EM drive. I have thought for quite some time that this was the most likely outcome (based on a lack of correlation between input power and output thrust). They believe that the EM field of the cabling was most likely interacting with the Earth's magnetic field (resulting in apparent thrust). I think they are continuing research, so all may not be lost yet.
https://arstechnica.com/science/2018/05/nasas-em-drive-is-a-magnetic-wtf-thruster/ Jack
