Boeing has been selected by the US Defense Advanced Research Projects Agency (DARPA) to develop and fly the SolarEagle unmanned aircraft for the Vulture II demonstration programme.

Under the $89m contract, Boeing will develop a full-scale flight demonstrator, including maturation of the critical power system and structures technologies.

Boeing Phantom Works programme manager for Vulture II Pat O’Neil said the aircraft is a large unmanned aircraft designed to remain on station at stratospheric altitudes for five years.

The demonstrator will remain in the upper atmosphere for 30 days, storing solar energy in fuel cells to provide power through the night.

The aircraft will have efficient electric motors and propellers, and a 400ft wing for increased solar power and aerodynamic performance.

Suppliers for the programme include Versa Power Systems and QinetiQ. The aircraft is expected make its first demonstration flight in 2014.