B-2A Spirit

B-2 Spirit
A U.S. Air Force B-2 Spirit flying over the Pacific Ocean in May 2006
Role	Strategic stealth bomber
National origin	United States
Manufacturer	Northrop Corporation Northrop Grumman
First flight	17 July 1989
Introduction	April 1997
Status	In service
Primary user	United States Air Force
Produced	1987–2000
Number built	21
Program cost	US$44.75 billion (through 2004)
Unit cost	$737 million (1997 approx. flyaway cost)

The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy penetration strategic bomber, featuring low observable stealth technology designed for penetrating dense anti-aircraft defenses; it is a flying wing design with a crew of two. The bomber can deploy both conventional and thermonuclear weapons, such as eighty 500 lb (230 kg)-class (Mk 82) JDAM Global Positioning System-guided bombs, or sixteen 2,400 lb (1,100 kg) B83 nuclear bombs. The B-2 is the only acknowledged aircraft that can carry large air-to-surface standoff weapons in a stealth configuration.

Development originally started under the "Advanced Technology Bomber" (ATB) project during the Carter administration; its expected performance was one of his reasons for the cancellation of the supersonic B-1A bomber. The ATB project 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, later Northrop Grumman, the cost of each aircraft averaged US$737 million (in 1997 dollars). 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.