In a quiet announcement that has sent shockwaves through the scientific world, NASA has cautiously given its seal of approval to a new type of impossible" engine that could revolutionize space travel. In a paper published by the agency's experimental Eagleworks Laboratories, NASA engineers confirmed that they had produced tiny amounts of thrust from an engine without propellant - an apparent violation of the conservation of momentum; the law of physics that states that every action must have an equal and opposite reaction. NASA's engineers have tested an engine known as a 'Cannae Drive', a machine [that] uses electricity to generate microwaves, bouncing them around inside a specially designed container that theoretically creates a difference in radiation pressure and so results in directional thrust. In an ordinary engine the rocket moves forward as fuel is flung backwards - the momentum of the rocket (a measure of both its mass and velocity combined) is 'conserved' because it is moved from the rocket to the fuel. However, with the Cannae Drive there is no fuel - the microwaves aren't expelled from the engine. NASA's scientists tested a version of the drive designed by US scientist Guido Fetta and found that the propellantless engine was able to produce between 30 and 50 micronewtons of thrust - a tiny amount (0.00003 to 0.00005 per cent of the force of an iPhone pressing down when held in the hand) but still a great deal more than nothing.