According to Flight Global, DARPA is close to awarding a contract to build an unmanned aircraft that can stay in the air for up to 5 years at a time. DARPA describes the "Vulture" project as a "persistent pseudo-satellite capability in an aircraft package." In other words, the aircraft can hover over a single area, narcing, communicating, or surveying for years at a time.
As with most lofty goals, there are major obstacles to contend with. First and foremost, the designers are going to have to figure out how to power such an aircraft over the course of these long missions. Oh, and it will have to do it while carrying a 1000 pound payload in the fearsome winds at a 60,000—90,000 feet. No problem right? As for the design, the Vulture will most likely draw on NASA designs like the one pictured above, but there is no definitive time table on when we might actually see a working craft. [Flight Global via CNET via DVICE]