HOW TO DEPLOY A MARK 3
THE DESIGN FOR THE FAT MAN nuclear bomb dropped on Nagasaki, Japan, was the basis for the Mark 3, which weighed more than five tons and was a bit over 10 feet long and five feet in diameter. Like the Nagasaki bomb, it was less a munition than an elaborate science project. “‘Bomb’ is a misnomer for this complex and delicate mechanism,” wrote Frederick Alling of the Air Materiel Command.
According to an Army War College paper written by then-lieutenant Colonel Trent Pickering, the Mark 3 was a “laboratory weapon” that took 39 men two days to prepare for combat. Then three assembly teams needed seven to nine days to load 12 bombs into 12 aircraft. The bomb’s batteries had to be charged 48 hours prior to a drop, and its polonium initiator, down in the fissile plutonium core, had a half-life of 138 days, so a crucial component was always in a state of rapid radioactive decay. Several days were also required to unite the assembled bombs with their fissile cores, which were often stored an ocean apart.
A jacked-up B-29 is ready to be armed with a nuclear bomb. Before this method, B-29s would roll over shallow bomb pits, and a hydraulic lift would push the weapon up into the bomb bay.