The Implosion-Based Bomb

The Hanford facility began producing plutonium in significant amounts and sent the first shipment to Los Alamos in February 1945. The only way the plutonium was going to be useful is if they could prove the implosion method would work. By late 1944, they were pretty sure that the uranium gun method was viable. At 5.30 in the morning on July 16th, they used a firing tower to hold the bomb and to approximate where the bomb would be before it detonated.