Photos: Solar-powered UAV flies and flies

The 30-kilogram (66-pound) Zephyr is launched by hand. All of the updated technologies in the spindly carbon-fiber aircraft were getting their shakedown cruise: the solar arrays, the Sion Power batteries, the solar charger and a "bespoke autopilot" from Qinetiq itself. The Zephyr performed two test flights, both with an unspecified surveillance payload. The first was the 54-hour flight, which soared to a top altitude of 58,355 feet, and the second was for 33 hours, 43 minutes, up to just over 52,000 feet.

The flight trials were funded by the U.K. Ministry of Defence. Qinetiq said that the flights demonstrated the ability of an autonomous, solar-powered UAV (unmanned aerial vehicle) "to support persistent military operations."