Enola Gay: Mission to Hiroshima

Prologue

On August 2, 1939, a month before World War II began in Europe, Albert Einstein signed a letter addressed to President Franklin Delano Roosevelt. Couched in careful terms, the letter stated that recent nuclear research indicated “extremely powerful bombs of a new type,” based on uranium, might soon be possible. Einstein warned that secret work with uranium was going on in Nazi Germany. He urged that similar American research be accelerated.

Alexander Sachs, economist, financier, and friend of Roosevelt, agreed to deliver the letter to the president. Before he could do so, war in Europe broke out, and Roosevelt was unable to see him until mid-October. Then, after much persuasion by Sachs, Roosevelt marked Einstein’s letter for action.

The first result of the president’s decision was the expenditure of just six thousand dollars. It bought graphite, essential for one of the early experiments that would, in time, lead to the atomic bomb. Substantial funds for the specific purpose of producing such a bomb were first authorized by Roosevelt on December 6, 1941.

Next day came Pearl Harbor. Roosevelt vowed vengeance. “Remember Pearl Harbor” became the rallying cry.

By the summer of 1942, it was clear that enormous amounts of money and effort would be required to build an atomic bomb. Huge manufacturing and processing plants had to be erected in remote areas to produce the sometimes dangerous materials required; research work in widely scattered university and commercial laboratories had to be initiated and put on a wartime footing; new laboratories needed to be created. And all in the utmost secrecy.

A cover name was invented for the project: the Manhattan Engineer District, later simplified to the Manhattan Project.

In October 1942, Site Y, Los Alamos, in the New Mexico desert, was chosen by physicist J. Robert Oppenheimer, a former pupil at the Los Alamos Ranch School for Boys, for his key research laboratory. His old classrooms would come to be used by eminent scientists, among them Enrico Fermi, Edward Teller, and that other giant of European physics, Niels Bohr.

It was Fermi who masterminded the crucial experiment on December 2, 1942, that produced the chain reaction needed to make an atomic bomb. He conducted his experiment on a bitterly cold day in an unused squash court at the University of Chicago. There were fears that the city itself might be endangered by the nuclear energy released. But the reaction was controlled, and scientists had demonstrated that when a uranium atom splits, it releases neutrons which can themselves then split more uranium atoms, creating the chain reaction. They formally christened this process “The K Factor”; among themselves they called it “The Great God K.”

In secret war plants during the following months a sense of urgency hovered over the complex processes for producing the relatively small amounts of uranium 235 needed to make atomic bombs. Plutonium, also suitable for atomic weapons, was being produced as well.

Roosevelt backed the project without the knowledge of Congress or the electorate. Funds for the venture were disguised in the federal budget. Eventually, two billion dollars would be spent in financing the work.

By 1944, a deep division was brewing among the scientists. Those now opposed to the military use of their research included Niels Bohr, who, in late August 1944, asked Roosevelt to authorize the sharing of U.S. atomic secrets with the world’s scientific community. He believed science belonged to the world.

At about the same time during the summer of 1944, uranium 235 was beginning to be produced in the quantities required for a weapon. Success seemed in sight. The problem of how to enclose “The Great God K” in a bomb casing was being dealt with. If, despite the qualms of some of the scientists, work was to go forward, the time had come to choose the man to train and lead the men who would drop the bomb.