Solar drone stays aloft for record 7 days: company

An ultra-light unmanned aircraft powered by solar energy and designed for military surveillance and other uses has stayed in the air a record seven days, its manufacturer said Friday.

The British-based firm QinetiQ said its 22.5 meter (74-foot) long Zephyr, weighing just 50 kilos (110 pounds), continued to fly over a US military testing ground in Arizona, and could stay aloft for another week.

The flight doubled the unofficial world record for the longest duration unmanned flight of 82 hours by the same aircraft in 2008. Zephyr's records will not become official until the aircraft is back on the ground.

"The current goal is to fly for a further week and prove Zephyr is the world's first truly eternal plane, capable of providing a low-cost, persistent surveillance capability over months rather than days," a company statement said.

"Potential applications include earth observation and communications relay in support of a range of defense, security and commercial requirements."

The latest model of the carbon-fiber Zephyr is around 50 percent bigger than earlier versions, giving it more space for batteries. The batteries are charged by the sun to allow it to continue flying at night.