By Gayle Putrich
Boeing will redefine "long endurance" for unmanned air vehicles, having won a contract to build a solar-powered flying wing intended to stay aloft for five years at a time under the US Defense Advanced Research Projects Agency's (DARPA) Vulture programme, the Pentagon agency announced on 15 September.
The first test of the Phantom Works prototype will be to fly the UAV, which Boeing has designated the Solar Eagle, for 30 days on solar-electric power. However, Phantom Works president Darryl Davis says: "Our plan is to go for much longer than that."
The Solar Eagle and its more than 122m (400ft) long wing will eventually be expected to fly for more than five years at a time at heights of 60,000-90,000ft carrying a 450kg (1,000lb) payload with minimum on-board power of 5kW/h.
DARPA documents from September 2009 that lay out the particulars for the $155 million second phase of Vulture list the "stretch goals" for Phase II as being able to carry a 90kg payload with 1kW/h of power with 99% reliability on a 90-day test flight. Phase II will also include risk reduction efforts for the UAV's systems and design and construction of a full-scale demonstrator. "The programme will conclude with a flight experiment of a near full-scale demonstrator," says DARPA's press release today.
With Pentagon demands for surveillance, intelligence and reconnaissance data from both air and satellite assets constantly increasing, DARPA's goal with Vulture is to combine the advantages of both types. The agency could potentially operate the system as a single aircraft, in a multi-aircraft formation or as a further-reaching satellite constellation.
"The Vulture technology offers a revolutionary capability of affordable, persistent airborne operation that shatters some fundamental aviation and space paradigms," says Daniel Newman, DARPA programme manager. "It is applicable to a wide range of current missions and applications, and offers new opportunities for tomorrow's requirements."
Boeing's partners in the venture to build the solar-powered UAV include Versa Power Systems, Draper Laboratories and Qinetiq, which unofficially reset the world record for high-altitude, long-endurance unmanned flight on 23 July, when its Zephyr UAV landed after 14 days and 21min in the air.
Boeing beat rival offerings from Lockheed Martin and from Aurora Flight Science's Odysseus, both of which also received funding in the first, 12-month phase of the Vulture programme, which began in April 2008. Boeing received $3.8 million in 2008 for Phase I development, which included blueprinting full-scale demonstrators, constructing subscale demonstrators and concluded with a system requirements review.