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National Museum of Nuclear Science & History

William R. Stewart

Engineer – Explosives DivisionLos Alamos, NM

Marshall IslandsTrinity Site
Manhattan Project VeteranMilitary VeteranPacific Nuclear TestsPostwar Nuclear ProgramSpecial Engineer DetachmentTrinity Test Eyewitness
Read William Stewart’s Personal Notes – August 19, 1945Read William Stewart’s Personal Notes on Day of Trinity Test

William Stewart was an engineer in the Special Engineering Detachment at Los Alamos, New Mexico. Specifically, Stewart worked in “Project Trinity” under the leadership of George Kistiakowsky and Kenneth Bainbridge. Stewart helped set up the Trinity test of the plutonium implosion weapon and witnessed the first atomic explosion in history on July 16, 1945.

He was discharged in March of 1946 and hired as a civilian (via the University of California, Berekley) to go to the Bikini Atoll for work with Operation Crossroads, the first series of postwar atomic tests.

William R. Stewart’s Timeline
1944 Mar 20th Arrived in Lamy, New Mexico before being sent to Los Alamos.

1944 Assigned to Explosives Division under the leadership of George Kistiakowsky and Kenneth Bainbridge

1945 Jul Helped set up the Trinity test and witnessed first atomic detonation on July 16 in Alamogordo, New Mexico

1946 Mar Discharged from military and from Manhattan Project. However, Stewart stayed continued to work on the development of atomic weapons and participated in Operation Crossroads, the first series of postwar atomic tests.

Pictured is a diary kept by William Stewart while at Los Alamos from May 1944. Note his reference on the 23rd to "Kisky," likely indicating the leader of the Explosives Division, George Kistiakowsky. 

Pictured is a copy of William Stewart's recommendation from the Scientific Director at Los Alamos, J. Robert Oppenheimer. The vague terms used in the reference letter show how secretive the Project was, even after the dropping of the atomic bombs. 

Pictured is a copy of William Stewart's recommendation from the Scientific Director at Los Alamos, J. Robert Oppenheimer. The vague terms used in the reference letter show how secretive the Project was, even after the dropping of the atomic bombs. 

Telegram requesting draft board release for William R. Stewart be sent immediately or "atomic bomb navy test will be delayed" 

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