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1944: Developing the Bomb

1944: Developing the Bomb

Timeline Image: 
B Reactor Workers

1944 Dec 22

First Fat Man bomb assembly is completed as production gets underway. Explosive lenses and nuclear material are not yet available, the bomb assemblies are used for airdrop and ground handling practice.

1944 Dec 17

The D pile goes critical at Hanford, WA with sufficient reactivity to overcome fission product poisoning effects. Large scale plutonium production begins.

1944 Dec

First successful explosive lens tests conducted at Los Alamos, NM, establishing the feasibility of making an implosion bomb.

1944 Dec 8

Polish Physicist Joseph Rotblat resigns from the Manhattan Project upon learning that an American atomic bomb will not be used against Nazi Germany.