Unmanned Aerial Vehicle (UAV)

One of the major problems with UAVs is the lack of inflight refueling capability. Currently the US Air Force is promoting research that should end in an inflight UAV refueling capability. The first UAV-UAV refueling flights are expected sometime during the first half of 2012.
One of the uses for a high endurance UAV would be to "stare" at the battlefield for a long period of time to produce a record of events that could then be played backwards to track where improvised explosive devices (IEDs) came from. Air Force Chief of Staff John P. Jumper started a program to create these persistent UAVs, but this was stopped once he was replaced.
The Defense Advanced Research Projects Agency (DARPA) is to sign a contract on building an UAV which should have an enormous endurance capability of about 5 years. The project is entitled "Vulture" and a September 15, 2010 news release indicated DARPA’s Vulture Program Enters Phase II. The developers are certain neither on the design of the UAV nor on what fuel it should run to be able to stay in air without any maintenance for such a long period of time.