(snip) Key is the fact that the diameter of a tubular cavity alters the path –
and hence the effective velocity – of the microwaves travelling through
The short version is microwaves are shot into a tube. The tube is shaped like a cone with one end smaller than the other. This causes more force to be directed against the large end of the cone than the smaller end. That force difference creates propulsion which can be used for space craft. If it works….
The only thing people fight about more than energy is God. Increases in efficiency and alternatives are a good thing. Via digg.