One of the most exciting articles on applications of theoretical science in a while. Most scientists with a name would not comment on this due to there being too much of a stirrup. Points go to Shawyer for bravery in taking on the hard-held status-quo narrow-mindedness. For people who would criticise this pioneering research, I would recommend to re-read their textbooks on Classical Relativity, Quantum Mechanics, and Particle Physics (assuming they had ones). While thinking about implications of Classical Relativity, Quantum Mechanics, and Particle Physics, as they relate to the emdrive, keep in mind that these have been fully consistent with experimental research.
Let me try to rebute this criticism:
Challenge: The principle of conservation of momentum is violated by the fact that nothing emerges from the electro-magnetic drive.
Rebuttal:The laws of Newton are a special case in relativity when velocity is close to zero. Since the electro-magnetic micro-waves can be considered to be particles moving at the speed of light, their energy and momentum is transferred to the surface on which they dissipate. Their energy is partly lost to heat and partly converted to kinetic energy. This effect is well known and documented. Now, considering the electro-magnetic drive tube, in which these micro-waves oscillate and dissipate, due to the tube's unevenly spaced ends, the momentum conversion results in overall thrust directed through the greater end of the tube, where the majority of dissipation occurs. This is the same principle that explains the aero-dynamic lift. The principle of conservation of momentum is satisfied by the electro-magnetic micro-waves' dissipation into heat and kinetic energy on tube surface.