Lawrence Johnston earned his undergraduate degree from the University of California, Berkley in 1940.
From 1940 to 1943, Johnston worked at the MIT Radiation Laboratory where he and Luis Alvarez invented the Ground-Controlled-Approach radar landing system which made it possible for people on the ground to talk pilots in for a safe landing. This radar system helped pilots during World War II, and made possible the Berlin Airlift.
During his two years working on the Manhattan Project at Los Alamos, Johnston led a team responsible for the ultra-fast detonators needed for implosion bombs. For the bombs