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"B-2 Spirit Bomber." //northrop grumman//. northrop grumman, nd. Web. 22 Sep. 2010. . “The U.S. Air Force's B-2 stealth bomber is the flagship of the nation's long-range strike arsenal, and one of the most survivable aircraft in the world. Its unique capabilities, including its stealth characteristics, allow it to penetrate the most sophisticated defenses and hold at risk high value, heavily defended enemy targets. The B-2 has demonstrated its capabilities in several combat scenarios, most recently during Operation Iraqi Freedom. The B-2 is the only U.S. aircraft that combines long range, large payload and stealth in a single platform, giving it the ability to project air power anywhere in the world. It can fly more than 6,000 nautical miles unrefueled and more than 10,000 nautical miles with just one aerial refueling. With its ability to carry more than 20 tons of conventional and nuclear ordnance and deliver it precisely under any weather conditions, the B-2 also has the ability to change the outcome of a conflict with a single mission. Northrop Grumman, the B-2 prime contractor, leads an industry team that is working with the Air Force to modernize the B-2 to ensure that it remains fully mission capable against evolving worldwide threats. A range of upgrade programs are improving the B-2's lethality; its ability to collect, process and disseminate battlefield information with joint force commanders or other local first responders worldwide; and its ability to receive updated target information during a mission. Twenty one aircraft were built in the original B-2 fleet. Today, the fleet consists of 20 aircraft, following the loss, in Feb 2008, of the Spirit of Kansas, which crashed while taking off from Andersen Air Force Base, Guam, the first such incident in the B-2's 19 years of operation. Since 1989, B-2 aircraft have flown more than 14,000 sorties and accumulated more than 75,000 flying hours without incident, an unprecedented safety record. Nineteen B-2s are currently based at Whiteman Air Force Base, Mo., home of the 509th Bomb Wing, while one aircraft is assigned to flight-testing at Edwards AFB, Calif. to validate software and weapon systems upgrades.“