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  • The Northrop B-2 Spirit, also known as the Stealth Bomber, is an American strategic bomber,

  • featuring low observable stealth technology designed for penetrating dense anti-aircraft

  • defenses; it is able to deploy both conventional and nuclear weapons. The bomber has a crew

  • of two and can drop up to eighty 500 lb-class JDAM GPS-guided bombs, or sixteen 2,400 lb

  • B83 nuclear bombs. The B-2 is the only aircraft that can carry large air-to-surface standoff

  • weapons in a stealth configuration. Development originally started under the "Advanced

  • Technology Bomber" project during the Carter administration, and its performance was one

  • of his reasons for the cancellation of the supersonic Rockwell B-1 Lancer. 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 rose throughout development.

  • Designed and manufactured by Northrop Grumman with assistance from Boeing, the cost of each

  • aircraft averaged US$737 million. Total procurement costs averaged $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.

  • Because 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 purchase 132 bombers to 21.

  • In 2008, a B-2 was destroyed in a crash shortly after takeoff, and the crew ejected safely.

  • A total of 20 B-2s remain in service with the United States Air Force, who plan to operate

  • the B-2 until 2058. The B-2 is capable of all-altitude attack

  • missions up to 50,000 feet, with a range of more than 6,000 nautical miles unrefuelled

  • and over 10,000 nautical miles with one refueling. Though originally designed primarily as a

  • nuclear bomber, it was first used in combat to drop conventional bombs on Serbia during

  • the Kosovo War in 1999, and saw continued use during the war in Iraq and in Afghanistan.

  • Development Origins

  • In the mid-1970s, the search for a new U.S. strategic bomber to replace the Boeing B-52

  • Stratofortress was underway, to no avail. First the B-70 and then the B-1A were canceled

  • after only prototypes of each aircraft were built. The B-70 was intended to fly above

  • and beyond defensive interceptor aircraft, only to find these same attributes made it

  • especially vulnerable to surface-to-air missiles. The B-1 attempted to avoid SAMs by flying

  • close to the ground to use terrain to mask its radar signature, only to face a new generation

  • of interceptors with look-down/shoot-down capabilities that could attack them from above.

  • By the mid-1970s, it was becoming clear that there was a different way to avoid missiles

  • and intercepts; known today as "stealth"; the concept was to build an aircraft with

  • an airframe that deflected or absorbed radar signals so that little was reflected back

  • to the radar unit. An aircraft having stealth characteristics would be able to fly nearly

  • undetected and could be attacked only by weapons and systems not relying on radar. Although

  • such possibilities existed, such as human observation, their relatively short detection

  • range allowed most aircraft to fly undetected by defenses, especially at night.

  • In 1974, DARPA requested information from U.S. aviation firms about the largest radar

  • cross-section of an aircraft that would remain effectively invisible to radars. Initially,

  • Northrop and McDonnell Douglas were selected for further development. Lockheed had experience

  • in this field due to developing the Lockheed A-12 and SR-71, which included a number of

  • stealthy features, notably its canted vertical stabilizers, the use of composite materials

  • in key locations, and the overall surface finish in radar-absorbing paint. A key improvement

  • was the introduction of computer models used to predict the radar reflections from flat

  • surfaces where collected data drove the design of a "faceted" aircraft. Development of the

  • first such designs started in 1975 with "the hopeless diamond", a model Lockheed built

  • to test the concept. Plans were well advanced by the summer of

  • 1975, when DARPA started the Experimental Survivability Testbed project. Northrop and

  • Lockheed were awarded contracts in the first round of testing. Lockheed received the sole

  • award for the second test round in April 1976 leading to the Have Blue program.

  • ATB program By 1976, these programs progressed to where

  • a long-range strategic stealth bomber appeared viable. President Carter was aware of these

  • developments during 1977, and it appears to have been one of the major reasons the B-1

  • was canceled. Further studies were ordered in early 1978, by which point the Have Blue

  • platform had flown and proven the concepts. During the 1980 presidential election in 1979,

  • Ronald Reagan repeatedly stated that Carter was weak on defense, and used the B-1 as a

  • prime example. In return, on 22 August 1980, the Carter administration publicly disclosed

  • that the United States Department of Defense was working to develop stealth aircraft, including

  • a bomber.

  • The Advanced Technology Bomber began in 1979. Full development of the black project followed,

  • and was funded under the code name "Aurora". After the evaluations of the companies' proposals,

  • the ATB competition was narrowed to the Northrop/Boeing and Lockheed/Rockwell teams with each receiving

  • a study contract for further work. Both teams used flying wing designs. Northrop had prior

  • experience developing the YB-35 and YB-49 flying wing aircraft. The Northrop design

  • was larger while the Lockheed design included a small tail. In 1979, designer Hal Markarian

  • produced a sketch of the aircraft, that bore considerable similarities to the final design.

  • The Air Force originally planned to procure 165 of the ATB bomber.

  • The Northrop/Boeing team's ATB design was selected over the Lockheed/Rockwell design

  • on 20 October 1981. The Northrop design received the designation B-2 and the name "Spirit".

  • The bomber's design was changed in the mid-1980s when the mission profile was changed from

  • high-altitude to low-altitude, terrain-following. The redesign delayed the B-2's first flight

  • by two years and added about US$1 billion to the program's cost. An estimated US$23 billion

  • was secretly spent for research and development on the B-2 by 1989. MIT engineers and scientists

  • helped assess the mission effectiveness of the aircraft under a five-year classified

  • contract during the 1980s. Secrecy and espionage

  • Both during development and in service, there has been considerable importance placed to

  • the security of the B-2 and its technologies. Staff working on the B-2 in most, if not all,

  • capacities have to achieve a level of special-access clearance, and undergo extensive background

  • checks carried out by a special branch of the Air Force.

  • For the manufacturing, a former Ford automobile assembly plant in Pico Rivera, California,

  • was acquired and heavily rebuilt; the plant's employees were sworn to complete secrecy regarding

  • their work. To avoid the possibility of suspicion, components were typically purchased through

  • front companies, military officials would visit out of uniform, and staff members were

  • routinely subjected to polygraph examinations. The secrecy extended so far that access to

  • nearly all information on the program by both Government Accountability Office and virtually

  • all members of Congress itself was severely limited until mid-1980s.

  • In 1984, a Northrop employee, Thomas Cavanaugh was arrested for attempting to sell classified

  • information to the Soviet Union; the information was taken from Northrop's Pico Rivera, California

  • factory. Cavanaugh was eventually sentenced to life in prison and released on parole in

  • 2001. The B-2 was first publicly displayed on 22

  • November 1988 at Air Force Plant 42, Palmdale, California, where it was assembled. This viewing

  • was heavily restricted, and guests were not allowed to see the rear of the B-2. However,

  • Aviation Week editors found that there were no airspace restrictions above the presentation

  • area and took photographs of the aircraft's then-secret planform and suppressed engine

  • exhausts from the air, to the USAF's disappointment. The B-2's first public flight was on 17 July

  • 1989 from Palmdale to Edwards AFB. In October 2005, Noshir Gowadia, a design

  • engineer who worked on the B-2's propulsion system, was arrested for selling B-2 related

  • classified information to foreign countries. On 9 August 2010, Gowadia was convicted in

  • the United States District Court for the District of Hawaii on 14 of 17 charges against him.

  • On 24 January 2011, Gowadia was sentenced to 32 years in prison.

  • Program costs and procurement A procurement of 132 aircraft was planned

  • in the mid-1980s, but was later reduced to 75. By the early 1990s, the Soviet Union dissolved,

  • effectively eliminating the Spirit's primary Cold War mission. Under budgetary pressures

  • and Congressional opposition, in his 1992 State of the Union Address, President George

  • H.W. Bush announced B-2 production would be limited to 20 aircraft. In 1996, however,

  • the Clinton administration, though originally committed to ending production of the bombers

  • at 20 aircraft, authorized the conversion of a 21st bomber, a prototype test model,

  • to Block 30 fully operational status at a cost of nearly $500 million.

  • In 1995, Northrop made a proposal to the USAF to build 20 additional aircraft with a flyaway

  • cost of $566 million each. The program was the subject of public controversy

  • for its cost to American taxpayers. In 1996, the General Accounting Office disclosed that

  • the USAF's B-2 bombers "will be, by far, the most costly bombers to operate on a per aircraft

  • basis", costing over three times as much as the B-1B and over four times as much as the

  • B-52H. In September 1997, each hour of B-2 flight necessitated 119 hours of maintenance

  • in turn. Comparable maintenance needs for the B-52 and the B-1B are 53 and 60 hours

  • respectively for each hour of flight. A key reason for this cost is the provision of air-conditioned

  • hangars large enough for the bomber's 172 ft wingspan, which are needed to maintain the

  • aircraft's stealthy properties, particularly its "low-observable" stealthy skins. Maintenance

  • costs are about $3.4 million a month for each aircraft.

  • The total "military construction" cost related to the program was projected to be US$553.6 million

  • in 1997 dollars. The cost to procure each B-2 was US$737 million in 1997 dollars, based

  • only on a fleet cost of US$15.48 billion. The procurement cost per aircraft as detailed

  • in GAO reports, which include spare parts and software support, was $929 million per

  • aircraft in 1997 dollars. The total program cost projected through 2004

  • was US$44.75 billion in 1997 dollars. This includes development, procurement, facilities,

  • construction, and spare parts. The total program cost averaged US$2.13 billion per aircraft.

  • The B-2 may cost up to $135,000 per flight hour to operate in 2010, which is about twice

  • that of the B-52 and B-1. Opposition

  • In its consideration of the fiscal year 1990 defense budget, the House Armed Services Committee

  • trimmed $800 million from the B-2 research and development budget, while at the same

  • time staving off a motion to end the project. Opposition in committee and in Congress was

  • mostly broad and bipartisan, with Congressmen Ron Dellums, John Kasich, and John G. Rowland

  • authorizing the motion to end the project, others in the Senate, such as Jim Exon and

  • John McCain, also opposing the project. The escalating cost of the B-2 program and

  • evidence of flaws in the aircraft's ability to elude detection by radar, were among factors

  • that drove opposition to continue the program. At the peak production period specified in

  • 1989, the schedule called for spending US$7 billion to $8 billion per year in 1989 dollars, something

  • Committee Chair Les Aspin said "won't fly financially." In 1990, the Department of Defense

  • accused Northrop of using faulty components in the flight control system; the threat posed

  • by bird ingestion potentially damaging engine fan blades also required redesigning.

  • In time, a number of prominent members of Congress began to oppose the program's expansion,

  • including former Democratic presidential nominee John Kerry, who cast votes against the B-2

  • in 1989, 1991 and 1992 while a U.S. Senator, representing Massachusetts. By 1992, Republican

  • President George H.W. Bush called for the cancellation of the B-2 and promised to cut

  • military spending by 30% in the wake of the collapse of the Soviet Union. In October 1995,

  • former Chief of Staff of the United States Air Force, General Mike Ryan, and former Chairman

  • of the Joint Chiefs of Staff, General John Shalikashvili, strongly recommended against

  • Congressional action to fund the purchase of any additional B-2s, arguing that to do

  • so would require unacceptable cuts in existing conventional and nuclear-capable aircraft,

  • and that the military had greater priorities in spending a limited budget.

  • Some B-2 advocates argued that procuring twenty additional aircraft would save money because

  • B-2s would be able to deeply penetrate anti-aircraft defenses and use low-cost, short-range attack

  • weapons rather than expensive standoff weapons. However, in 1995, the Congressional Budget

  • Office, and its Director of National Security Analysis, found that additional B-2s would

  • reduce the cost of expended munitions by less than US$2 billion in 1995 dollars during

  • the first two weeks of a conflict, in which the Air Force predicted bombers would make

  • their greatest contribution; a small fraction of the US$26.8 billion life cycle cost that

  • the CBO projected an additional 20 B-2s would cost.

  • In 1997, as Ranking Member of the House Armed Services Committee and National Security Committee,

  • Congressman Ron Dellums, a long-time opponent of the bomber, cited five independent studies

  • and offered an amendment to that year's defense authorization bill to cap production of the

  • bombers to the existing 21 aircraft; the amendment was narrowly defeated. Nonetheless, Congress

  • did not approve funding for the purchase of any additional B-2 bombers.

  • Further developments A number of upgrade packages have been applied

  • to the B-2. In July 2008, the B-2's onboard computing architecture was extensively redesigned;

  • it now incorporates a new integrated processing unit that communicates with systems throughout

  • the aircraft via a newly installed fibre optic network; a new version of the operational

  • flight program software was also developed, with legacy code converted from the JOVIAL

  • programming language used beforehand to standard C. Updates were also made to the weapon control

  • systems to enable strikes upon non-static targets, such as moving ground vehicles.

  • On 29 December 2008, Air Force officials awarded a US$468 million contract to Northrop Grumman

  • to modernize the B-2 fleet's radars. Changing the radar's frequency was required as the

  • U.S. Department of Commerce has sold that radio spectrum to another operator. In July

  • 2009, it was reported that the B-2 had successfully passed a major USAF audit. In 2010, it was

  • made public that the Air Force Research Laboratory had developed a new material to be used on

  • the part of the wing trailing edge subject to engine exhaust, replacing existing material

  • that quickly degraded. In 2013 the USAF contracted for the Defensive

  • Management System Modernization program to replace the antenna system and other electronics

  • to increase the B-2's frequency awareness. In July 2010, political analyst Rebecca Grant

  • speculated that when the B-2 becomes unable to reliably penetrate enemy defenses, the

  • Lockheed Martin F-35 Lightning II may take on its strike/interdiction mission, carrying

  • B61 nuclear bombs as a tactical bomber. However, in March 2012, the Pentagon announced that

  • a $2 billion, 10-year-long modernization of the B-2 fleet was to begin. The main area

  • of improvement would be replacement of outdated avionics and equipment.

  • It was reported in 2011 that the Pentagon was evaluating an unmanned stealth bomber,

  • characterized as a "mini-B-2", as a potential replacement in the near future. In 2012, Air

  • Force Chief of Staff General Norton Schwartz stated the B-2's 1980s-era stealth would make

  • it less survivable in future contested airspaces, so the USAF is to proceed with the Next-Generation

  • Bomber despite overall budget cuts. The Next-Generation Bomber was estimated, in 2012, to have a projected

  • overall cost of $55 billion. The Common Very Low Frequency Receiver upgrade

  • will allow the B-2s to use the same Very low frequency transmissions as the SSBNs so as

  • to continue in the nuclear mission until the Mobile User Objective System is fielded.

  • In 2014 the USAF outlined a series of upgrades including nuclear warfighting, a new integrated

  • processing unit, the ability to carry cruise missiles, and threat warning improvements.

  • Design Overview

  • 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 include nuclear

  • weapons. The B-2 is a flying wing aircraft, meaning it has no fuselage or tail. The blending

  • of low-observable technologies with high aerodynamic efficiency and large payload gives the B-2

  • significant advantages over previous bombers. Low observability provides a greater freedom

  • of action at high altitudes, thus increasing both range and field of view for onboard sensors.

  • The U.S. Air Force reports its range as approximately 6,000 nautical miles. At cruising altitude

  • the B-2 refuels every six hours, taking on up to 50 short tons 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 use of computer-aided design and manufacturing technologies. Northrop

  • Grumman is the B-2's prime contractor; other contributing subcontractors include Boeing,

  • Raytheon, G.E. and Vought Aircraft. The B-2 bears a resemblance 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 resemblance goes as far as B-2

  • and YB-49 having the same wingspan. As of September 2013 about 80 pilots fly the

  • B-2. Each aircraft has a crew of two, a pilot in the left seat 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-seat aircraft, one crew member can sleep in a camp bed, use a toilet,

  • or prepare a hot meal while the other monitors the aircraft; extensive sleep cycle and fatigue

  • research was conducted to improve crew performance on long sorties.

  • Armaments and equipment

  • The B-2, in the envisaged Cold War scenario, was to perform deep-penetrating nuclear strike

  • missions, making use 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