1944: Developing the Bomb

1944: Developing the Bomb

Timeline Image: 
B Reactor Workers

1944 Aug

Deak Parsons assesses February 1945 as the earliest an implosion lens system can be ready for full scale test "with extremely good breaks", and most likely late 1945.

1944 Aug

The Air Force begins modifying 17 B-29s for combat delivery of atomic weapons at the Glenn L. Martin plant in Omaha, Nebraska.

1944 July

Air Force Lt. Col. Paul Tibbets begins organizing the 509th Composite Group, which will deliver atomic bombs in combat, at Wendover Field, Utah.

1944 July 4

J. Robert Oppenheimer reveals Emilio Segre's spontaneous fission measurements to the Los Alamos, NM staff. The neutron emission for reactor-produced plutonium is too high for gun assembly to work. The measured rate is 50 fissions/kg-sec, the fission rate in Hanford, WA plutonium is expected to be over 100 times higher still. The discovery of the high spontaneous fission rate of reactor-produced plutonium was a turning point for Los Alamos, NM, the Manhattan Project, and eventually for the practice of large-scale science after the war.

1944 June 18

General Leslie Groves contracts to have the S-50 Plant, intended for liquid thermal diffusion uranium enrichment, built at Oak Ridge, TN in no more than three months.

June 3, 1944

After visiting the uranium enrichment pilot plant at the Naval Research Laboratory, a team of Manhattan Project experts recommends that a liquid thermal diffusion plant be built to feed enriched material to the electromagnetic enrichment plant at Oak Ridge, the S-50 Plant.