Propellant-free Propulsion?

To follow the perpetual motion flap last month, here’s another almost-too-good-to-be-true invention – a superconducting electromagnetic thruster engine. The brainchild of one Roger Shawyer, an aerospace engineer from the UK, the design uses a resonant cavity to amplify the force of photons fired into it. His second prototype can create a force of 300 milliNewtons, but Shawyer reckons he could get enough power to raise a passenger vehicle if he can find the right superconducting materials for the waveguide. The European science establishment are unimpressed, but the US and China are both very interested – only time will tell if this is solution or snake oil.