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The Northrop Grumman Global Hawk has its origins in the 1994 High-Altitude Endurance Unmanned Aerial Vehicle Advanced Concept Technology Demonstrator (HAE UAV ACTD) program initiated by the Defense Advanced Research Projects Agency (DARPA) and Defense Airborne Reconnaissance Office (DARO). This effort was undertaken as a reaction to the perceived excesses of the highly classified and enormously expensive Lockheed/Boeing Advanced Airborne Reconnaissance System (AARS) program initiated in the mid-1980s. A loitering long-range strategic reconnaissance UAV designed to penetrate contested airspace and carry a wide range of sensors, AARS was cancelled in May 1993 due to cost overruns and the loss of its main mission with the end of the Cold War.
Two distinct air vehicles and respective ground segments made up the HAE UAV ACTD program. Global Hawk was built to the Tier II+ requirement, which called for a conventionally configured UAV, while the Lockheed Martin/Boeing DarkStar fulfilled the Tier III- requirement for an unconventional low-observable UAV. DarkStar, primarily a technology demonstrator, quickly ran into trouble when it crashed during its second takeoff. DarkStar did not take to the air again until 26 months later, when test flights revealed unanticipated stability problems. These performance concerns, along with escalating costs, led to Air Force cancellation of the program after just six flights.
In the Phase I design competition for the Tier II+ platform, five contractors were invited to participate. This was reduced to one contractor, Teledyne Ryan Aeronautical (now part of Northrop Grumman), after budget cuts prior to the Phase II downselect. Very early in Phase III, Global Hawk demonstrated notable military utility and subsequently entered the formal acquisition process. The UAV's Common Ground Segment (CGS) was also a success, controlling the air vehicle as well as the transmission and dissemination of imagery.
Few aircraft have shown such utility and deployment capability so early in flight testing. Global Hawk's autonomous high-altitude, long-duration flight characteristics were proven, along with the capability of its Synthetic Aperture Radar (SAR) sensor to provide high-quality imagery. Though not part of the original requirement, Global Hawk and its sensors were also shown to be dynamically retaskable during its trials with the Air Force's 31st Test and Evaluation Squadron. The Global Hawk effort succeeded where DarkStar failed because it focused on the design and construction of a practical air vehicle that was developmentally mature enough to be transitioned into an operational weapons system.
Global Hawk RQ-4 Block 10
Wingspan: 116.2 ft (35.4 m)
Length: 44.4 ft (13.5 m)
Height: 15.2 ft (4.6 m)
Gross Take-off Weight: 26,700 lbs (12,110.9 kg)
Payload: 2,000 lbs (907.2 kg)
Ferry Range: 12,000 nm (22,236 km)
Maximum Altitude: More than 65,000 ft (19.8 km)
Loiter Velocity: 343 knots TAS
On-Station Endurance at 1,200 nm: 24 Hours
Maximum Endurance: 35 Hours (31.5 Hours Demonstrated)
Global Hawk RQ-4 Block 20/30/40
Wingspan: 130.9 ft (39.9 m)
Length: 47.6 ft (14.5 m)
Height: 15.3 ft (4.7 m)
Gross Take-off Weight: 32,250 lbs (14,628 kg)
Payload: 3,000 lbs (1,360 kg)
Ferry Range: 12,300 nm (22,780 km)
Maximum Altitude: More than 60,000 ft (18.3 km)
Loiter Velocity: 310 knots TAS
On-Station Endurance at 1,200 nm: 24 Hours
Maximum Endurance: 36 Hours
Sensors
Synthetic Aperture Radar: 1.0/0.3 M Resolution (WAS/Spot)
Electro-Optical: NIIRS 6.0/6.5 (WAS/Spot)
Infrared: NIIRS 5.0/5.5 (WAS/Spot) |
