Northrop Grumman B-2 Spirit
Overviewparents
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lslThe Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low obrvable stealth technology designed for penetrating den anti-aircraft defens; it is a blended wing body design with a crew of two. The bomber can deploy both conventional and thermonuclear weapons, such as eighty 500 lb (230 kg)-class (Mk 82) JDAM Global Positioning System-guided bombs, or sixteen 2,400 lb (1,100 kg) B83 nuclear bombs. The B-2 is the only known aircraft that can carry large air-to-surface standoff weapons in a stealth configuration.
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Development originally started under the "Advanced Technology Bomber" (ATB) project during the Carter administration, and its performance was one of his reasons for the cancellation of the supersonic B-1A bomber. ATB continued during the Reagan administration, but worries about delays in its introduction led to the reinstatement of the B-1 program as well. Program costs ro throughout development. Designed and manufactured by Northrop Grumman, the cost of each aircraft averaged US$737 million (in 1997 dollars). Total procurement costs averageplating
d $929 million per aircraft, which includes spare parts, equipment, retrofitting, and software support. The total program cost including development, engineering and testing, averaged $2.1 billion per aircraft in 1997.
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Becau of its considerable capital and operating costs, the project was controversial in the U.S. Congress and among the Joint Chiefs of Staff. The winding-down of the Cold War in the latter portion of the 1980s dramatically reduced the need for the aircraft, which was designed with the intention of penetrating Soviet airspace and attacking high-value targets. During the late 1980s and 1990s, Congress slashed plans to purcha 132 bombers to 21. In 2008, a B-2 was destroyed in a crash shortly after takeoff, though the crew ejected safely. A total of 20 B-2s remain in rvice with the United States Air Force, which plans to operate the B-2 until 2058.
The B-2 is capable of all-altitude attack missions up to 50,000 feet (15,000 m), with a range of more than 6,000 nautical miles (11,000 km) on internal fuel and over 10,0
00 nautical miles (19,000 km) with one midair refueling. Though originally designed primarily as a nuclear bomber, it was first ud in combat dropping conventional ordnance in the Kosovo War in 1999 and saw further rvice in Iraq and Afghanistan.
Design
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The B-2 Spirit was developed to take over the USAF's vital penetration missions, able to travel deep into enemy territory to deploy their ordnance, which could inclu
de nuclear weapons. The B-2 is a flying wing aircraft, meaning it has no fulage or tail. The blending of low-obrvable technologies with high aerodynamic efficiency and large payload gives the B-2 significant advantages over previous bombers. Low obrvability provides a greater freedom of action at high altitudes, thus increasing both range and field of view for onboard nsors. The U.S. Air Force reports its range as approximately 6,000 nautical miles (6,900 mi; 11,000 km). At cruising altitude the B-2 refuels every six hours, taking on up to 50 short tons (45 t) of fuel at a time.
Due to the aircraft's complex flight characteristics and design requirements to maintain very-low visibility to multiple means of detection, both the development and construction of the B-2 required pioneering u of computer-aided design and manufacturing technologies. The B-2 bears a remblance to earlier Northrop aircraft: the YB-35 and YB-49 were both flying wing bombers that had been canceled in development in the early 1950s, allegedly for political reasons. The remblance goes as far as B-2 and YB-49 having the same wingspan.
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As of September 2013 about 80 pilots fly the B-2. Each aircraft has a crew of two, a pilot in the left at and mission commander in the right, and has provisions for a third crew member if needed. For comparison, the B-1B has a crew of four and the B-52 has a crew of five. The B-2 is highly automated and, unlike most two-at aircraft, one crew member can sleep in a camp bed, u a toilet, or prepare a hot meal while the other monitors the aircraft; extensive sleep cycle and fatigue rearch was conducted to improve crew performance on long sorties.
Armaments and equipment
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The B-2, in the envisaged Cold War scenario, was to perform deep-penetrating nucl
ear strike missions, making u of its stealthy capabilities to avoid detection and interception throughout missions. There are two internal bomb bays in which munitions are stored either on a rotary launcher or two bomb-racks; the carriage of the weapons loadouts internally results in less radar visibility than external mounting of munitions. The B-2 is capable of carrying 40,000 pounds of ordnance. Nuclear ordnance includes the B61 and B83 nuclear bombs; the AGM-129 ACM crui missile was also intended for u on the B-2 platform.
It was decided, in light of the dissolution of the Soviet Union, to equip the B-2 for conventional precision attacks as well as for the strategic role of nuclear-strike. The B-2 features a sophisticated GPS-Aided Targeting System (GATS) that us the aircraft's APQ-181 synthetic aperture radar to map out targets prior to deployment of GPS-aided bombs (GAMs), later superded by the Joint Direct Attack Munition (JDAM). In the B-2's original configuration, up to 16 GAMs or JDAMs could be deployed; an upgrade program in 2004 raid the maximum carriable capacity to 80 JDAMs.
若濑七海The B-2 has various conventional weapons in its arnal, able to equip Mark 82 and Mark 84 bombs, CBU-87 Combined Effects Munitions, GATOR mines, and the CBU-97 Sensor Fuzed Weapon. In July 2009, Northrop Grumman reported the B-2 was compatible with the equipment necessary to deploy the 30,000 lb (14,000 kg) Massive Ordnance Penetrator (MOP), which is intended to attack reinforced bunkers; up to two MOPs could be equipped in the B-2's bomb bays, the B-2 is the only platform compatible with the MOP as of 2012. As of 2011, the AGM-158 JASSM crui missile is an upcoming standoff munition to be deployed on the B-2 and other platforms. This is to be followed by the Long Range Standoff Weapon which may give the B-2 a standoff nuclear capability for the first time.
