The Global Hawk Unmanned Aerial Vehicle (UAV) provides Air Force and joint battlefield commanders near-real-time, high-resolution, intelligence, surveillance and reconnaissance imagery. It flies autonomously at an altitude of 65,000 feet, above inclement weather and prevailing winds for more than 35 hours. During a single mission, it provides detailed intelligence, surveillance and reconnaissance information on a 40,000 square mile area in near-real time.

Once mission parameters are programmed into Global Hawk, the UAV can autonomously taxi, take off, fly, remain on station capturing imagery, return and land. Ground-based operators monitor UAV health and status, and can change navigation and sensor plans during flight as necessary.

Global Hawk, which has a wingspan of 116 feet (35.3 meters) and is 44 feet (13.4 meters) long, can range as far as 12,000 nautical miles, at altitudes up to 65,000 feet (19,812 meters), flying at speeds approaching 340 knots (about 400 mph) for as long as 35 hours.

During a typical mission, the aircraft can fly 1,200 miles to an area of interest and remain on station for 24 hours. Its cloud-penetrating, Synthetic Aperture Radar/Ground Moving Target Indicator, electro-optical and infrared sensors can image an area the size of Illinois (40,000 nautical square miles) in just 24 hours.

Through satellite and ground systems, the imagery can be relayed in near-real-time to battlefield commanders. When fully-fueled for flight, Global Hawk weighs approximately 25,600 pounds (11,612 kilograms). More than half the UAV's components are constructed of lightweight, high-strength composite materials, including its wings, wing fairings, empennage, engine cover, engine intake and three radomes. Its main fuselage is standard aluminum, semi-monocoque construction.

RQ-4B

The RQ-4B is the next-generation, enhanced-capability version of Global Hawk. Northrop Grumman is currently producing four RQ-4B Global Hawks at its Palmdale, Calif. production facility.

With 3,000 pounds of payload capacity, the RQ-4B Global Hawk offers 50 percent more payload capacity than its currently deployed "sibling," the RQ-4A. This added capability will allow it to carry more intelligence sensors, enhancing its ability to simultaneously collect imagery, signals intelligence and infrared and radar information, and transfer it to the warfighter in near-real time.

To accommodate the increased payload capacity, Northrop Grumman has redesigned and strengthened Global Hawk's fuselage. The RQ-4B's fuselage is four feet longer and just slightly taller than the RQ-4A's. The wingspan has also increased by approximately fifteen feet, allowing the RQ-4B to carry more fuel. The RQ-4B also features a gross take-off weight 5500 pounds heavier than that of the RQ-4A.

The principal contractors for Global Hawk are:

• Northrop Grumman's Ryan Aeronautical Center, San Diego, Calif. -- prime contractor
• Raytheon Systems Company units at Falls Church, Va., and El Segundo, Calif. -- ground segment and sensors
• Rolls-Royce Allison, Indianapolis, Ind. -- turbofan engine
• Vought Aircraft Company, Dallas, Texas. -- carbon-fiber wing
• L3 Com, Salt Lake City, Utah -- communications systems