In 1988 the B-2 Spirit was finally introduced to the public in Palmdale, California. Northrop Grumman led the project, while Boeing built the outer aircraft. For example, Boeing built the: aft center fuselage section, landing gears, fuel system and weapons delivery system, etc. While, Northrop Grumman did other work. The cost to develop the B-2 was roughly 40 billion dollars. The price per unit was an estimate of more than 1 billion dollars. Then in 1989, the B-2 was finally flown. The wingspan of the aircraft is longer than half a football field, at roughly 172’0”. The Bomber could reach speeds upwards of 600 mph. The maximum payload the B-2 Spirit can hold is over 40,000 pounds. The B-2 had 4 General Electric F-118-GE-100 non after-burning turbo fans, with each engine having 17,300lbs of thrust. The B-2 Spirit was undetectable by infrared, sound detectors, and the naked eye. The purchase order was supposedly supposed to be over 100 B-2 Spirits, but because the Cold War was coming to a close there was a less demand for them. So congress only purchases 21 B-2 Spirits. The United States Air Force plans to operate them till 2032, says Air force Magazine.