Aircraft takes off on solar-powered flight

A long, thin flying wing intended to fly higher than any unmanned aircraft ever has taken off on its first solar-powered test flight.

The remotely-piloted aircraft called Helios took off from the Pacific Missile Range Facility in Hawaii.

The aircraft headed west across the Pacific.

The flight, aiming for an altitude of 70,000 feet to 80,000 feet was expected to continue into the night.

"It will take eight hours to get up to altitude," said John Hicks, programme manager for the project .

Later this summer, researchers intend to send the plane to 100,000 feet, a record for an unmanned aircraft, more than three times higher than commercial jets fly.

Helios is a 247ft-long flying wing that measures only eight feet front to back.

The $15m aircraft is controlled from the ground by two pilots using desktop computers. Its 14 propellers are driven by small electric motors powered by solar cells built into the wing.

Helios was built by a partnership of the National Aeronautics and Space Administration and AeroVironment Inc of Monrovia, California, which has produced many innovative aircraft including the human-powered Gossamer Albatross.

AeroVironment's smaller Pathfinder solar-powered airplane flew to a record altitude of more than 80,000 feet in 1998.