One of the more unique unmanned aircraft took a giant step toward reality this week when the Defense Advanced Research Projects Agency inked an agreement with Boeing to build the SolarEagle, a plane capable of remaining at heights over 60,000 feet for more than five years. Boeing says the first SolarEagle under the $89 million contract could fly as early as 2014.

The SolarEagle is built under DARPA's Vulture program. The idea is to build a single aircraft that could support traditional intelligence, surveillance and reconnaissance functions over country-sized areas, while at the same time providing an unblinking eye over a critical target, monitoring that target night and day, day in and day out, month after month, providing unprecedented high value intelligence. Vulture aircraft will also be able to provide communications capabilities available today only from geostationary satellites, offering opportunities for new, more flexible, expandable and relocatable communication architectures at a fraction of the cost of dedicated satellite capabilities. The challenges with Vulture include developing solar cell, energy storage and reliability technologies that will allow the aircraft to operate continuously, unrefueled for over 44,000 hours, DARPA stated.

Under the Vulture II agreement, Boeing will develop a full scale flight demonstrator, including maturation of the critical power system and structures technologies. Key suppliers for the programme include Versa Power Systems and QinetiQ.

During testing, the SolarEagle demonstrator will remain in the upper atmosphere for 30 days, harvesting solar energy during the day that will be stored in fuel cells and used to provide power through the night. The aircraft will have highly efficient electric motors and propellers and a high aspect ratio, 400-foot wing for increased solar power and aerodynamic performance, Boeing stated.

Boeing has been on a roll this week. Earlier it had announced a marriage with outer space tourism proprietors Space Adventures to offer low Earth orbit (LEO) flight services onboard Boeing's future commercial crew spacecraft. Under the agreement, Space Adventures will market passenger seats on commercial flights aboard the Boeing Crew Space Transportation-100 (CST-100) spacecraft.

Boeing's (CST)-100, which is under development, can hold seven and is bigger than NASA's Apollo orbiter but smaller than NASA's Orion. Boeing says the ship will be able to launch on a variety of different rockets, including Atlas, Delta and Falcon. It will use simple systems architecture and existing, proven components, Boeing stated.