The Northrop Grumman RQ-4 Global Hawk is an unmanned aerial vehicle (UAV) used as a surveillance aircraft. It can survey as much as 100,000 square kilometers of terrain a day, able to provide high resolution Synthetic Aperture Radar (SAR) that can penetrate cloud-cover and sandstorms, and Electro-Optical/Infrared (EO/IR) imagery at long range with loiter times over target areas. Global Hawk ATCD prototypes have been used in the War in Afghanistan and the Iraq War. On April 24, 2001, a Global Hawk flew nonstop from Edwards Air Force Base in the US to RAAF Base Edinburgh in Australia, making history by being the first pilotless aircraft to cross the Pacific Ocean. The flight took 22 hours.