Trinity’s Key Players
Major General Leslie Groves, builder of the Pentagon and Commander of the Manhattan Project. 
J. Robert Oppenheimer, Laboratory Director at the Los Alamos facility. 
Cyril Smith, British metallurgist responsible for production of fissionable materials for the bombs. 
George Kistiakowsky, Harvard professor in charge of the Manhattan Project’s Explosives Division, the group responsible for designing the explosive lenses that would compress the plutonium core to critical mass. 
Marshall Holloway, an American physicist in charge of turning theoretical nuclear equations into Trinity’s reality. 
Louis Slotin, a Canadian physicist who helped Marshall Holloway develop a cyclotron, a type of particle accelerator, for the Manhattan Project. Louis Slotin would become the second person to die of accidental criticality when he accidentally began a fusion reaction in his lab. 
Boyce McDaniel, an American nuclear physicist who worked to perfect Trinity’s cyclotron. McDaniel would perform the final check on Trinity before detonation. 
Major General Thomas Farrel, the Manhattan Project’s Deputy Commanding General and Chief of Field Operations. 
Philip Morrison, an American physicist responsible for calculating the required amount of plutonium that the bomb required. J. Robert Oppenheimer was Morrison’s doctoral advisor at the University of California, Berkeley. 
The team of the Manhattan Project’s key personnel near the test site.
In 1942, Colonel Leslie Groves, who had just completed building the Pentagon under budget and ahead of schedule was promoted to Brigadier General and assigned to command the Manhattan Project’s nation-wide effort – build the Los Alamos lab, the Oakridge TN and Hanford WA enrichment sites, and, when it was needed, Trinity. Knowing Germany was working on a fission bomb, he was also responsible for atomic intelligence gathering and Army special operations soldiers trained to attack German atomic assets. Groves was an unpopular, blunt and hot-tempered officer who knew little about physics, but he was an engineer and a dedicated and gifted career soldier who got things done. He appointed the brilliant J. Robert Oppenheimer as his Los Alamos Lab Director responsible for the development of the bomb that would be tested at Trinity.