Northrop B-2 Spirit
The Northrop B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying wing with a crew of two, the plane was designed by Northrop (later Northrop Grumman) as the prime contractor, with Boeing, Hughes, and Vought as principal subcontractors, and was produced from 1987 to 2000.[1][3] The bomber can drop conventional and thermonuclear weapons,[4] such as up to eighty 500-pound class (230 kg) Mk 82 JDAM GPS-guided bombs, or sixteen 2,400-pound (1,100 kg) B83 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.
Several terms redirect here. For other uses, see B2 (disambiguation).
Development began under the Advanced Technology Bomber (ATB) project during the Carter administration, which cancelled the Mach 2-capable B-1A bomber in part because the ATB showed such promise. But development difficulties delayed progress and drove up costs. Ultimately, the program produced 21 B-2s at an average cost of $2.13 billion (~$4.04 billion in 2023), including development, engineering, testing, production, and procurement.[5] Building each aircraft cost an average of US$737 million,[5] while total procurement costs (including production, spare parts, equipment, retrofitting, and software support) averaged $929 million (~$1.11 billion in 2023) per plane.[5] The project's considerable capital and operating costs made it controversial in the U.S. Congress even before the winding down of the Cold War dramatically reduced the desire for a stealth aircraft designed to strike deep in Soviet territory. Consequently, in the late 1980s and 1990s lawmakers shrank the planned purchase of 132 bombers to 21.
The B-2 can perform attack missions at altitudes of up to 50,000 feet (15,000 m); it has an unrefueled range of more than 6,000 nautical miles (6,900 mi; 11,000 km) and can fly more than 10,000 nautical miles (12,000 mi; 19,000 km) with one midair refueling. It entered service in 1997 as the second aircraft designed with advanced stealth technology, after the Lockheed F-117 Nighthawk attack aircraft. Primarily designed as a nuclear bomber, the B-2 was first used in combat to drop conventional, non-nuclear ordnance in the Kosovo War in 1999. It was later used in Iraq, Afghanistan, and Libya.[6]
The United States Air Force has nineteen B-2s in service as of 2024;[7] one was destroyed in a 2008 crash[8] and another was lost to a crash in 2022.[7] The Air Force plans to operate them until 2032, when the Northrop Grumman B-21 Raider is to replace them.[9]
Development[edit]
Origins[edit]
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.[10]
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.[11] 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.[12]
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.[13] 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.[14]
ATB program[edit]
By 1976, these programs had progressed to a position in which a long-range strategic stealth bomber appeared viable. 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.[15] 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 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.[16]
United States Air Force (19 aircraft in active inventory)