From Wired's Danger Room blog:
Also at Danger Room, a silent Jimmy Carter:
No unmanned aircraft in the American arsenal flies higher or longer than the Global Hawk. On Tuesday, it soared high and long, powered by a blend of synthetic fuel. The Northrop-built drone touched down late Tuesday night at Edwards Air Force Base in Southern California after spending more than a day aloft.
Both the Navy and Air Force have flown numerous other aircraft using other non-traditional jet fuels, but this is both the first for an unmanned aircraft, and the first time any type of aircraft has flown with this type of fuel. JP-8 jet fuel (the kind typically used in the Air Force) was combined with a synthetic paraffinic kerosene derived from liqufied coal, and another derived from natural gas, to make up the blend.
Along with other branches of the military, the Air Force is busy developing and implementing alternatives to the petroleum-based jet fuels that have powered its turbine powered aircraft since the late 1940s. The plan is to have 50 percent of domestic aviation fuel for the Air Force come from an alternative fuel blend by 2016. The synthetic paraffinic kerosene (SPK for those acronym loving people in the Pentagon) is the latest fuel to be tested.
Three Air Force aircraft, the A-10, F-15 and C-17, have all been flown using a blend of JP-8 and a renewable fuel made from plant oils and animal fats. The F-22 stealth fighter and Global Hawk are expected to fly on this hydro-processed renewable jet fuel, or HRJ, fuel next year.
Super-Silent Jimmy Carter Ready to Spy on North Korea