Solar record

A solar-powered Unmanned Aerial Vehicle (UAV) has set a world record, flying for three and a half days at the US Army's Yuma Proving Ground in Arizona.

Qinetiq's so-called Zephyr high-altitude long-endurance (HALE) aircraft flew for 82 hours and 37 minutes, exceeding the current official world record for unmanned flight of 30 hours and 24 minutes, which was set by Global Hawk in 2001, and beating its own previous longest flight of 54 hours achieved last year.

The US Department of Defense (DoD) funded the demonstration flight under its Joint Capability Technology Demonstration (JCTD) Programme, which is designed to move technologies rapidly into the hands of US forces in the field. This was the first time the two governments participated in a joint demonstration of the HALE UAV.

Launched by hand, Zephyr is an ultra-lightweight carbon-fibre aircraft. By day, it flies on solar power generated by amorphous silicon solar arrays no thicker than sheets of paper that cover the aircraft's wings. By night, it is powered by rechargeable lithium-sulphur batteries, supplied by Sion Power, which are recharged during the day using solar power.

During the flight trial, Zephyr was flown on autopilot and through satellite communications to a maximum altitude of more than 60,000ft.