File:130125-F-FP673-241.jpg

A U.S. Air Force RQ-4 Global Hawk unmanned aerial vehicle prepares to land as a MC-12 Liberty aircraft waits for takeoff at Beale Air Force Base, Calif., Jan. 25, 2013. Pave Paws Radar Site in the background. public domain (U.S. Air Force Photo by Mr. John Schwab/ Released)