Harold Agnew (1921-2013) was an American physicist and director of the Los Alamos National Laboratory from 1970-1979.
Agnew saw the completion of the atomic bomb from start to finish. As a member of Enrico Fermi's research team at the University of Chicago in 1942, Agnew witnessed the first sustained nuclear chain reaction, Chicago Pile-1. He worked in the Experimental Physics Division at Los Alamos from 1943 to 1945.
While the Trinity test was being conducted, Agnew was already on his way to Tinian Island in the Pacific as part of Project Alberta, the group responsible for the final bomb assembly. He flew as a scientific observer on a B-29 bomber for the Hiroshima bombing mission, measuring the size of the shock wave to determine the bomb’s power. He also filmed the explosion with a movie camera.
After the war he returned to school and received his Ph.D. in physics in 1949. He returned to Los Alamos during the Cold War, working on the hydrogen bomb. Agnew became head of the Weapon Nuclear Engineering Division in 1964, and went on to serve as director of the Los Alamos National Laboratory from 1970 to 1979, as well as a presidential advisor under Ronald Reagan. Agnew retired in 1979 to become Chief Executive Officer of General Atomics until 1985.