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