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Army General and Physicist Helped Usher in the Atomic Age

No one person can be credited with producing the world's first atomic bomb but two men had outsize achievements in that effort: physicist J. Robert Oppenheimer and Army Lt. Gen. Leslie Groves.

Two men talk outside on parched, desolate ground.
Oppenheimer and Groves
Physicist J. Robert Oppenheimer, left, and Army Maj. Gen. Leslie Groves in 1945 at the site of the remains of the Trinity atomic test in New Mexico.
Photo By: Army
VIRIN: 450904-O-D0439-001

On Oct. 9, 1941, President Franklin D. Roosevelt approved the development of the atomic bomb, partly out of intelligence reports that Nazi Germany might acquire one first.

Roosevelt chose the Army to lead the project, as that service had much experience managing large-scale construction projects.

In September 1942, Groves was appointed director of the ultra-secret Manhattan Project, the code name for the vast effort to produce the bomb. Groves had extensive experience supervising big projects as an engineer, including construction of the Pentagon, and he was widely recognized as a leader who got jobs done on time no matter what.

Two men talk as they look at a document.
Groves and Oppenheimer
Army Maj. Gen. Leslie Groves, left, and physicist J. Robert Oppenheimer work on creation of the atomic bomb during World War II.
Photo By: Army
VIRIN: 450704-O-D0439-003

Groves approved a number of critically important research and engineering endeavors; he also approved production sites for work on the bomb, including Oak Ridge, Tennessee; Los Alamos, New Mexico; and Hanford, Washington.

As leader of the project, Groves directed construction at those sites; made key decisions in the bomb's manufacture process; directed intelligence on German efforts to produce a bomb; and, once the bombs were ready for delivery in 1945, selected targets in an effort to shorten the war.

Another one of Groves' important decisions was selecting Oppenheimer to lead the physics aspects of making the bomb.

A man appears in an old, black and white photo.
J. Robert Oppenheimer
Physicist J. Robert Oppenheimer is seen in photograph taken in 1944.
Photo By: Department of Energy
VIRIN: 440604-O-D0439-001

Both Groves and Oppenheimer had the talent, drive and leadership qualities that enabled production of the bomb on a very short timeline.

The first nuclear test occurred near Alamogordo, New Mexico, on July 16, 1945. The bomb was successfully used later that year.

A historic photo shows a nuclear bomb exploding.
Nuclear Bomb
The first nuclear bomb is detonated in 1945 at the Trinity test site in New Mexico.
Photo By: Department of Energy
VIRIN: 450704-O-D0439-001C

Postwar Developments

Developments during World War II later led to harnessing the technology to produce:

  • Nuclear-powered submarines and aircraft carriers.
  • The U.S. nuclear-triad defense, consisting of nuclear delivery from submarines, strategic bombers and intercontinental ballistic missiles.
  • Nuclear power for producing energy for peaceful purposes.

After the end of World War II, the Manhattan Project continued to support atomic weapons testing until the Atomic Energy Act of 1946 split the program into two parts: the Atomic Energy Commission, known today as the Department of Energy, and the Armed Forces Special Weapons Project.

The organization responsible for the aspects of the nuclear weapons remained under military control after the split. It was responsible for nuclear weapons maintenance, storage, surveillance, security and transportation, and conducting offensive and defensive military training in nuclear weapons operations and supporting nuclear tests.

A movie poster bears the word Oppenheimer.
The film “Oppenheimer” chronicles the work of physicist J. Robert Oppenheimer. It’s set for release July 21, 2023.
Photo By: Courtesy of Universal Pictures
VIRIN: 230720-O-D0439-001

The Defense Department's Defense Threat Reduction Agency traces its roots back to the Manhattan Project in 1942, according to the agency's website.

A large number of books have been written about the Manhattan Project and the people involved in it. A biography of Oppenheimer, "American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer," was published in 2005. It was written by Kai Bird and Martin J. Sherwin.

That book was adapted into the film "Oppenheimer," which is set for release tomorrow. Directed by Christopher Nolan, it stars Cillian Murphy as Oppenheimer, Emily Blunt as Oppenheimer's wife, and Matt Damon as Groves.

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