Groves and Oppenheimer were the main leaders of the Manhattan Project.

In June, 1942, the U.S. Department of War began to implement the plan to develop an atomic bomb by nuclear fission reaction, also known as Manhattan Project. The project concentrated the best nuclear scientists in the western countries (except Nazi Germany) at that time, mobilized more than 654.38 million people to participate, lasted for three years and cost 2 billion US dollars. 1945, 16 In July, the world's first nuclear explosion was successfully carried out, and two practical atomic bombs were manufactured as planned. The whole project was a complete success. In the process of project implementation, leaders L.R. groves and R. Oppenheimer applied the ideas and methods of systems engineering, which greatly shortened the project time. The success of this project promoted the development of system engineering after World War II.

1945 July 15 At 5: 30 am, the world's first atomic bomb exploded in a desert area in Alamogordo, New Mexico (because the name of the test site is also called trinity explosion). ) The test was successful. On July 25th, an atomic bomb was successfully tested in Bikini Atoll in the Pacific Ocean. On August 6 and 9, the United States dropped atomic bombs on Hiroshima and Nagasaki, Japan. With the Soviet troops sending troops to the northeast of China, the Japanese emperor declared unconditional surrender on 15, and the Second World War ended.