British scientist Roger Shawyer has been trying to interest people in his EmDrive for some years through his company SPR Ltd. Shawyer claims the EmDrive converts electric power into thrust, without the need for any propellant by bouncing microwaves around in a closed container. He has built a number of demonstration systems[…]a US scientist, Guido Fetta, has built his own propellant-less microwave thruster, and managed to persuade Nasa to test it out. The test results were presented on July 30 at the 50th Joint Propulsion Conference in Cleveland, Ohio. Astonishingly enough, they are positive[…]he Nasa team has avoided trying to explain its results in favour of simply reporting what it found: “This paper will not address the physics of the quantum vacuum plasma thruster, but instead will describe the test integration, test operations, and the results obtained from the test campaign.”[…]A working microwave thruster would radically cut the cost of satellites and space stations and extend their working life, drive deep-space missions, and take astronauts to Mars in weeks rather than months. In hindsight, it may turn out to be another great British invention that someone else turned into a success.

via Nasa validates 'impossible' space drive (Wired UK).