United States Department of Defense - RQ-4 Global Hawk

The Northrop Grumman (formerly Ryan Aeronautical) RQ-4 Global Hawk (known as Tier II+ during development) is an unmanned aerial vehicle (UAV) used by the US Air Force as a surveillance aircraft.

n role and design, it is somewhat similar to the Lockheed U-2, the venerable 1950s spy plane. It is a theater commander's asset to both provide a broad overview and systematically target surveillance shortfalls. The Global Hawk air vehicle is 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 long loiter times over target areas. It can survey as much as 100,000 square kilometers (40,000 square miles) of terrain a day. If a Global Hawk were flown out from San Francisco, it would be able to operate in Maine for 24 hours, observe a 370 x 370 kilometer (230 x 230 mile) grid, and then fly back home.

Potential missions for the Global Hawk cover the spectrum of intelligence collection capability to support forces in worldwide peace, crisis, and wartime operations. According to the Air Force, the capabilities of the aircraft will allow more precise targeting of weapons and better protection of forces through superior surveillance capabilities.

The "R" is the Department of Defense designation for reconnaissance; "Q" means unmanned aircraft system. The "4" refers to it being the fourth of a series of purpose-built unmanned aircraft systems. "A" or "B" refers to these being the first and second versions, respectively.

The Global Hawk is the first UAV to be certified by the FAA to file its own flight plans and use civilian air corridors in the United States with no advance notice. This potentially paves the way for a revolution in unmanned flight, including that of automatically piloted passenger airliners.

The RQ-4 is powered by an Allison Rolls-Royce AE3007H turbofan engine with 31.4 kN (3,200 kgf / 7,050 lbf) thrust, and carries a payload of 900 kilograms (2,000 pounds). The fuselage is mostly of conventional aluminum airframe construction, while the wings are made of carbon composite.

The Global Hawk costs about $35 million USD each (actual per-aircraft costs; with development costs also included, the per-aircraft cost rises to $123.2 million USD each).