It’s always exciting when something seemingly impossible is validated by NASA—the smartest of the smart when it comes to cutting-edge aeronautical technology, right? Well, NASA scientists have just confirmed that an “impossible” technology is in fact possible.
Agency scientists validated that a microwave thruster really works. However, it’s an announcement that could turn out to be a bit like the faster-than-light neutrinos that on closer inspection turned out to be regular old slower-than-light particles: These findings are based on just eight days of studies. Still, that NASA is interested means it’s something we ought to pay attention to.
The “impossible” technology in this instance is called the EmDrive. It’s the brainchild of British engineer Roger Shawyer and it theoretically works by converting electric power into thrust by bouncing microwaves around in a closed container. There’s no propellant involved in this system, which makes it a compelling technology for spaceflight. Fuel, or propellant in the case of thrust rockets, is necessarily in limited quantities on any given spacecraft; it’s heavy to launch, and when it’s used up a spacecraft has little to no way of reorienting itself or altering its trajectory.
But a propellant-free system would be a game changer. If a spacecraft, say a deep space probe like New Horizons, which is less than a year from its encounter with Pluto, didn’t need propellant, that extra weight and space could be devoted to scientific instruments, larger solar arrays, or a larger power source.
The problem with the EmDrive is that, according to the laws of the conservation of momentum, it shouldn't work.
For the rest of the story: http://motherboard.vice.com/read/nasa-resurrects-once-thought-impossible-microwave-thruster-technology