A controversial British antigravity device is to be investigated by the government's National Space Centre, according to reports. If the technology really works, it would be able to counteract the force of gravity using only electrical power, permitting the easy building of Jetsons-style flying cars or hoverships and hugely simplifying space travel.

The kit in question is the "Emdrive" - brainchild of engineer Roger Shawyer - which some readers may already be familiar with. It supposedly works by generating high-power microwaves within a special closed wave guide. Somehow or other - it's to do with relativity, according to Shawyer - the microwaves push harder on one end of the tin than the other, causing a thrust to be generated from nothing more than electrical power - no reaction mass required.

Naturally a lot of people assert that this is bunk. In particular, Dr John Costella, Aussie physicist and expert on relativistic electrodynamics - the very stuff which is supposed to make the Emdrive work - says it's a fraud, and also uses (pdf) ugly words like "crackpot" and "charlatan". On the other side of the coin, Shawyer is a bona-fide Fellow of the Royal Aeronautical Society (we checked with them) - which would normally indicate status as a flying-stuff boffin of some substance.

The Emdrive has already received funding and investigation from the British government in the last few years, and Shawyer has built a demonstration unit which appears to generate enough thrust to rotate itself on an air bearing (see the vid above). He says that more powerful second-generation kit using superconducting niobium wave cavities cooled by liquid helium would be able to generate much more powerful forces - lifting tonnes per kilowatt put in.

One might think that this would enable mighty electric spaceships to flit easily between the planets - but, interestingly, Shawyer denies this. He says that the thrust drops off rapidly once the generator starts moving along the line of thrust, so that the kit would really only be of much use to nullify an opposing force - for instance that of gravity. Your spaceship would find getting away from Earth much easier, but it would still need some other propulsion in order to pick up speed: your car or yacht could easily float in midair using only a horsepower or two to hold itself up (plus the power needed for the liquid-helium chiller gear) but it would need jets or props to move along.

Sadly for all those still waiting for their antigrav car, sky yacht, cheap and easy space launch etc. it seems quite likely that it's all a load of cobblers. But not everybody is convinced of this: Flight International reports that a deputy director at the British National Space Centre - the nearest thing the UK has to a government space agency - envisages a "workshop" on the Emdrive next year. Shawyer has been exhibiting his kit at the European Air and Space Conference in Manchester this week. ®