B53 Thermonuclear Bomb An enduring symbol of the Cold War, the B53 was one of the longest-lived nuclear weapons fielded by the United States, and it remained a key element of nuclear deterrence until retired in 1997. First produced in 1962, the Mk-53 "hydrogen" bomb -- later redesignated B53 -- was carried internally by B-47, B-52 and B-58 aircraft. It was equipped with five parachutes: one 5-foot pilot chute, one 16-foot chute and three 48-foot chutes. However, the "can" containing the parachutes could also be jettisoned for a free-fall delivery. With a yield in the megaton range, B53s had an air burst, contact burst, and "laydown" (delayed action detonation) capability. The Mk-6 re-entry vehicle installed on the Titan II ICBM contained a W53 warhead, basically the same as the B53 bomb. Babcock & Wilcox Technical Services Pantex (B&W Pantex) dismantled the retired B53s at its facility near Amarillo, Texas, for the US Department of Energy and the National Nuclear Security Administration. The B53 on display was the last B53 in US inventory, and B&W Pantex completed its dismantlement in October 2011. It was transferred to the museum in 2012. Click here to return to the Cold War Gallery. Find Out More Related Fact Sheets Boeing B-52D Stratofortress Convair B-58A Hustler Note: The appearance of hyperlinks does not constitute endorsement by the National Museum of the USAF, the U.S. Air Force, or the Department of Defense, of the external website, or the information, products or services contained therein.