Correct me if I'm wrong here, but didn't the EM drive only prove to move a very tiny distance, like thousands or millionths of a inch? I was under the impression that it'd still require massive amounts of energy and size to be able to produce enough thrust to achieve serious speed.

I guess in a vacuum like space though, while slow to start, a continual increase in speed, even if small would amount to a lot. Can the microwave energy be recycled, or does it have to be continually applied to achieve thrust, even though there isn't any "loss" in energy through output?