Monday, February 11, 2019

Inventor, Atomic Bomb Witness, and University Professor Larry Johnston [otd 02/11]

Larry Johnston, ca 1945. U. S. Army.
Physicist Lawrence Harding “Larry” Johnston was born February 11, 1918, in Shantung (Shandong) Province, China. His parents were missionaries, who returned to the U. S. in 1923, probably to avoid Nationalistic unrest in the area. By 1930, his father held a position as a Presbyterian pastor in Santa Maria, California.

Like many boys of that era, Larry was fascinated by electricity. That led him to a B.S. degree in physics from the University of California at Berkeley. One of his professors was Luis W. Alvarez, later a Nobel Prize winner, but then a newly-minted Ph.D. and faculty member.

The U.S. had not yet entered World War II when Larry graduated in 1940. He began graduate school on schedule, intending to work for Alvarez. However, the professor took a leave of absence to consult at the Massachusetts Institute of Technology (MIT). The “temporary” assignment soon lengthened, and Alvarez drafted Johnston to help. Larry arrived at MIT in January of 1941.

Much of the work there sought to improve the relatively new technology of radar. Soon, Alvarez made Larry the Project Engineer for what became a Ground Control Approach (GCA) radar system. The system provides precise data on a plane’s altitude, and its track versus the runway centerline. A ground controller uses that information to “talk the pilot down.”
Trinity Test Blast. National Archives.
Then Robert Oppenheimer recruited Alvarez for the atomic bomb project, working out of Los Alamos, New Mexico. Alvarez, in turn, brought along Larry. The details are beyond the scope of this blog, but Johnston tackled, and solved, the detonation trigger array for the plutonium-239 atomic bomb (“Fat Man”). In the summer of 1945, he witnessed the first atomic detonation in history at the Trinity site near Alamogordo.

A few days later, Johnston and his team were ordered to Tinian Island. From there, Larry rode an observation plane and witnessed the two atomic bombs dropped on Japan. He was the only person known to have seen all three of those first atomic explosions. They had also seen the enormous supply of coffins stockpiled in case the Allies had to physically invade Japan. A deeply religious man, Johnston later wrote that he and the bomber crews “had come to terms with the inevitable loss of life. We hoped for an early end to the War and its heavy drain of human life and potential.”

The terrible destruction gave the Japanese a face-saving way to avoid a fight to the death, something they were, indeed, prepared to do. Less than a week after the second bomb, they surrendered. After matters settled down, Johnston went back to graduate school at UC-Berkeley.
GCA Radar Console.
National Air and Space Museum.

During the winter of 1948, the GCA system he and Alcarez had pioneered made possible one of the most dramatic peacetime campaigns of the Twentieth Century: the Berlin Airlift. With ground controllers – the “unsung heroes” – talking them down through bad weather, daring pilots flew a steady stream of supply planes into blockaded Berlin. The Soviets finally gave up their unexpectedly-futile obstruction.

After receiving his doctorate in 1950, Johnston taught for over a decade at the University of Minnesota. He then worked back in California before becoming a physics professor at the University of Idaho in 1967. Some of his research results are still considered the definitive works in his field, and he was renowned as a teacher and mentor. After his retirement in 1978, Larry stayed active, including enthusiastic support of Christian ministries in Moscow.

He passed away in late 2011.
References: [Brit]
David Bergamini, Japan’s Imperial Conspiracy, William Morrow & Company, New York (1971).
Lawrence Johnston, “The War Years,” Discovering Alvarez, W. Peter Tower (ed.), The University of Chicago Press, Chicago (1987).
Sandra L. Lee, “Idaho Man Witness to 3 Atomic Blasts,” Lewiston Tribune, Lewiston, Idaho (November 19, 2011).
“Obituary: Lawrence H. 'Larry' Johnston, 93,” Moscow-Pullman Daily News, Moscow, Idaho (December 7, 2011).
Stewart M. Powell, “The Berlin Airlift,” Air Force Magazine, The Air force Association, Arlington, Virginia (June 1998).

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