The Northrop B-2 Spirit is an American nuclear-capable subsonic stealth strategic bomber, often referred to as a "stealth bomber", solely operated by the United States Air Force. A four-engined flying wing and lambda wing with a crew of two to three, it is designed with stealth technology to penetrate sophisticated air defenses. The B-2 was designed by Northrop (later Northrop Grumman) as the prime contractor, with Boeing, Hughes Aircraft Company, and Vought as principal subcontractors. It was produced from 1988 to 2000. The bomber can drop conventional and thermonuclear weapons, such as up to eighty 500-pound class (230 kg) Mk 82 JDAM GPS-guided bombs, or sixteen 400 kiloton B61 nuclear bombs. The B-2 is the only acknowledged in-service aircraft that can carry large air-to-surface standoff weapons in a stealth configuration. Development began in 1979, as the Advanced Technology Bomber (ATB) black project during the Carter administration. Its promises contributed to cancelling the Mach 2-capable B-1A bomber, but development difficulties delayed progress and drove up costs. By 1996, the program produced 21 B-2s at a total cost of $44.7 billion (equivalent to $91,820,000,000 in 2025) or average cost of $2.13 billion (equivalent to $4,370,000,000 in 2025) per aircraft, including procurement, development, testing, and production. The megaproject's considerable capital and operating costs made it controversial in the U.S. Congress, even before the end of the Cold War dramatically reduced the desire for a stealth aircraft to strike deep inside the Soviet Union; by the 1990s lawmakers shrank the planned purchase of 132 bombers to 21. The B-2 has an estimated flight ceiling of 50,000 feet (15 km), an unrefueled range of more than 6,900 miles (11,000 km) and can fly more than 12,000 miles (19,000 km) with one midair refueling. It entered service in 1997, considered the second stealth aircraft, after the Lockheed F-117 Nighthawk. Primarily designed as a nuclear bomber, the B-2 was first used in combat to drop conventional ordnance in the Kosovo War in 1999. It was later used in Iraq, Afghanistan, Libya, Yemen, the 2025 strikes on Iran and the 2026 Iran war. Based out of Whiteman AFB, Missouri, climate-controlled hangars have allowed the B-2 to forward deploy to NSF Diego Garcia in the Indian Ocean, Andersen AFB on Guam in the Pacific, and RAF Fairford in the United Kingdom. The United States Air Force has nineteen B-2s in service as of 2024. Another was destroyed in a 2008 crash, and one was likely retired from service after being damaged in a crash in 2022. The Air Force plans to operate the B-2s until 2032, as they are incrementally replaced by the Northrop Grumman B-21 Raider.
Development
Origins By the mid-1970s, military aircraft designers had learned of a new method to avoid missiles and interceptors, 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 radar stealth characteristics would be able to fly nearly undetected and could be attacked only by weapons and systems not relying on radar. Although other detection measures existed, such as human observation, infrared scanners, and acoustic locators, their relatively short detection range or poorly developed technology allowed most aircraft to fly undetected, or at least untracked, 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 with the development of the Lockheed A-12 and SR-71, which included several 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 Have Blue, 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 and eventually the F-117 stealth attack aircraft. Northrop also had a classified technology demonstration aircraft, the Tacit Blue in development in 1979 at Area 51. It developed stealth technology, LO (low observables), fly-by-wire, curved surfaces, composite materials, electronic intelligence, and Battlefield Surveillance Aircraft Experimental. The stealth technology developed from the program was later incorporated into other operational aircraft designs, including the B-2 stealth bomber.
Advanced Technology Bomber program By 1976, these programs had progressed to a position in which a long-range strategic stealth bomber appeared viable. U.S. president Jimmy Carter became 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 U.S. presidential election campaign in 1979, Ronald Reagan repeatedly stated that Carter was weak on defense and used the B-1 as a prime example. In response, 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.
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