The Northrop Grumman B-2 Spirit (also known as the Stealth Bomber) is an American heavy bomber with "low observable" stealth technology designed to penetrate dense anti-aircraft defences and deploy both conventional and nuclear weapons. Because of its considerable capital and operational costs, the project was controversial in the U.S. Congress and among the Joint Chiefs of Staff. During the late 1980s and early 1990s, the Congress slashed initial plans to purchase 132 bombers to just 21. The cost of each aircraft averaged US$737 million in 1997 dollars ($1.01 billion today). Total procurement costs averaged US$929 million per aircraft ($1.27 billion today), which includes spare parts, equipment, retrofitting, and software support. The total program cost, which includes development, engineering and testing, averaged US$2.1 billion per aircraft (in 1997 dollars, $2.87 billion today). Twenty B-2s are operated by the United States Air Force. Though originally designed in the 1980s for Cold War operations scenarios, B-2s were first used in combat to drop bombs on Serbia during the Kosovo War in 1999, and saw continued use during the ongoing wars in Iraq and Afghanistan. One aircraft was lost in 2008 when it crashed just after takeoff; the crew ejected safely. The bomber has a crew of two and can drop up to 80 x 500 lb (230 kg)-class JDAM GPS-guided bombs, or 16 x 2,400 lb (1,100 kg) B83 nuclear bombs in a single pass through extremely dense anti-aircraft defences. The B-2 is the only aircraft that can carry large air to surface standoff weapons in a stealth configuration. The program has been the subject of espionage and counter-espionage activity and the B-2 has provided prominent public spectacles at air shows since the 1990s.