THE RELATIVITY DRIVE
Could the engine of our science-fiction dreams be on the horizon?
The EmDrive is the brainchild of microwave engineer Roger Shawyer, who after 40 years with aerospace giants Sperry, BAE Systems and Astrium set out to pursue a remarkable idea: a thruster that can produce a force without any exhaust. The problem with rockets is that they need a reactive mass – something to throw away – so if you’re going to Mars you have to take all the propellants you’re going to need for the whole flight with you. Shawyer’s design is controversial, but it all comes down to one point of contention. The thruster consists of a closed tapering box, and microwaves beamed into the box bounce back and forth between the ends, with every bounce producing a small force. The ends are also shaped so the microwaves are focused away from the walls.