The Emthruster: Thrust without reaction?

[stevebowers]

This post by John Baez is instructive about the experiment, and some of its unusual features;
https://plus.google.com/1176630154135462...7vx2G85kr4
the experiment was conducted in a vacuum chamber, but without evacuating the air. This appears to be due to the fact that they couldn't get their instrumentation to work in a vacuum. But maybe this will be resolved later.