FAT MAN (model “Y-1561” / Mk.3)

After the resounding success of the Trinity test, the first nuclear explosion in history, work was accelerated to get an operational bomb available before the end of the War. The “Fat Man” bomb, as it was designated, was the second that could be finished and tested against a real enemy. On this occasion it was launched on August 9, 1945 against the Japanese city of Nagasaki. This bomb had a fissile mass of plutonium-239 and exploded through an implosion type trigger.

FAT MAN (model “1561” / Mk.3) gallery and more info


Información adicional

Ficha Completa
Country of origin

United States


Los Alamos Laboratory


Nuclear bomb

Entered service


Missile/bomb dimensions, (length x diameter)

3.24 x 1.52 meters

Missile/bomb weight

4,892 kg

Warhead, (explosive charge)

Weight: 6.19 kg – Material: Plutonium core – Type: fission implosion device

Yield, (maximum)

22 Kilotons


Y.1561 type: 3 – Mk.0/1/2 type: 53 – Mk.3 type: 120