] The US Air Force is examining the feasibility of a ] nuclear-powered version of an unmanned aircraft. The USAF ] hopes that such a vehicle will be able to "loiter" in the ] air for months without refuelling, striking at will when ] a target comes into its sights. ] ] ] With a nuclear drive a Global Hawk could fly for months ] without landing (Image: GETTY NEWSERVICE)] ] But the idea is bound to raise serious concerns about the ] wisdom of flying radioactive material in a combat ] aircraft. If shot down, for instance, would an ] anti-aircraft gunner in effect be detonating a dirty bomb New Scientist |