Northrop Grumman RQ-4 Global Hawk

The Northrop Grumman RQ-4 Global Hawk is a high-altitude, remotely piloted surveillance aircraft that entered use in 2001. Ryan Aeronautical designed it, and it was known as Tier II+ during development. It carries high-resolution synthetic aperture radar and electro-optical and infrared sensors with long loiter times over a target area, and the United States Air Force operates it as a high-altitude long-endurance platform for intelligence collection. The program survived in the 1990s when budget cuts forced a choice between it and the stealthy Lockheed Martin DarkStar, and the Global Hawk was chosen for its range and payload. It first flew on 28 February 1998 at Edwards Air Force Base. Cost overruns cut the planned purchase of 63 aircraft to 45, the U.S. Navy developed the airframe into the MQ-4C Triton, and the Air Force plans to retire its Global Hawks in 2027.