"This is the classic "why can't you put a big fan on the back of a sailboat to make it go" question. If both the emitter and the object it acts against are attached to each other, there is no actual thrust generated since the net mass of the system is still the same, i.e. nothing is being thrown "away." Now, if your emitter is located somewhere else besides the ship, like on the surface of the Moon, then this could work, in the same way as Bob Forward's laser driven solar sails."

I can see why this wouldn't work on Earth. The thrust of the wind from the fan hitting the sail would be canceled by the fan itself pushing the ship backward. In effect, the forward and rearward push cancels each other out. But if it's true that the radio waves have no reaction mass, but can still push an object they come into contact with (in the weightlessness of space), then it seems to me that it just might work in this case.

I hope this isn't getting old, I'm just trying to understand how something can have mass enough to push an object without having enough mass to exert an opposite reaction.

Lee, (Grasping at straws for a quick fix to space travel)