The Northrop (later Northrop Grumman) 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, and produced from 1987 to 2000.^[1][3] 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 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.

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 costs up. Ultimately, the program produced 21 B-2s at an average cost of $2.13 billion (in 1997 dollars), including development, engineering, testing, production, and procurement.^[4] Just building each aircraft cost an average of US$737 million,^[4] while total procurement costs (including production, spare parts, equipment, retrofitting, and software support) averaged $929 million per plane