What is the Manhattan Project?

The American Atomic Program Takes Shape

• The United States would begin the largest scientific endeavor carried out up to that point while participating in one war in Europe and another in the Pacific. 100,000 people would be involved, along with 37 facilities spread across the nation, more than a dozen university labs, and physicists who have won Nobel Prizes including Arthur Holly Compton, Enrico Fermi, Richard Feynman, Ernest Lawrence, and Harold Urey.
• George B. Pegram of Columbia University initiated the first communication between the scientific community and the US government regarding atomic research. Leo Szilard and Eugene Wigner met with Einstein in July 1939, and the three subsequently traveled to New York to meet with National Recovery Administration economist Alexander Sachs. Sachs approached President Franklin D. Roosevelt and conveyed the significance of nuclear fission to him, aided by a letter from Einstein. Roosevelt established the Uranium Advisory Committee, chaired by Lyman Briggs, head of the National Bureau of Standards.
• The nuclear aspirations of Adolf Hitler were now well-known to American officials. In his letter to Roosevelt, Einstein made clear that Czechoslovakia’s uranium stockpiles had come under the Third Reich’s authority in March 1939. A number of scientists from those nations relocated to the United States later that year to work on the project, which was already well underway. It was decided to work simultaneously on numerous techniques for separating uranium-235 while also conducting research into reactor development because there was no way to tell in advance which technology would be successful in constructing a functional weapon.
• At the University of California, Berkeley, Lawrence, and his team created an electromagnetic separation technique, while Urey’s team at Columbia University experimented with uranium conversion into a gaseous molecule that was then allowed to diffuse through porous barriers. To create even modest amounts of separated uranium-235, both of these processes—especially the diffusion method—required enormously complicated equipment and enormous amounts of electric power. It was soon obvious that a sizable physical infrastructure would need to be constructed to support the endeavor.

From Stagg Field to Los Alamos

• On June 18, 1942, the War Department assigned the Manhattan District of the United States Army Corps of Engineers the responsibility of project construction administration. On September 17, 1942, Brig. Gen. Leslie R. Groves was given command of all Army efforts linked to the project. For this extensive program of atomic research that would cover the nation, the “Manhattan Project” was chosen as the code name.
• In Chicago Pile No. 1, a reactor he constructed on a squash court behind the bleachers of Stagg Field, the university’s football stadium, Fermi oversaw the first self-sustaining nuclear chain reaction on December 2, 1942. It had now been proven that controlled atomic energy release could be used to produce plutonium and generate electricity.
• Groves decided to build the project’s plutonium production facilities on a 580 square mile (1,500 square kilometers) parcel of land in south-central Washington in January 1943. The area was picked because of its relative remoteness, as well as the Columbia River’s enormous supply of cooling water and the hydroelectric plants at Grand Coulee and Bonneville’s plentiful supply of energy.
• A significant amount of the local population had to be relocated because of the development of what is now known as the Hanford Engineer Works. The Wanapum Native American people were forced to migrate to Priest Rapids and lost access to their customary fishing grounds on the Columbia. Residents of Hanford, Richland, and White Bluffs were given 90 days to vacate. In the summer of 1944, the enormous Hanford complex was at its busiest and employed over 50,000 people.
• For the project’s final phases, a location that was even more remote than Hanford was necessary for security and safety concerns. The scientific head of the Manhattan Project, J. Robert Oppenheimer, picked a spot on a remote mesa in Los Alamos, New Mexico, some 55 kilometers (34 miles) north of Santa Fe. In April 1943, the Los Alamos Laboratory, as it was then known, opened its doors to scientists and engineers.
• Under Oppenheimer’s direction, this group was tasked with coming up with strategies for turning the fissionable byproducts of the Clinton and Hanford manufacturing facilities into pure metal and shaping that metal into the elements of a deliverable bomb. The Los Alamos site housed more than 5,000 scientists, engineers, technicians, and their families at its busiest in 1945.

The Trinity Test

• Despite the hundreds of man-hours spent preparing for this moment, a few workers at the Trinity site had concerns that the bomb would set off as anticipated. Nobody in person was able to accurately forecast all the different theoretical variables. Many precautions for security were set into effect in order to be prepared to face any number of disaster situations. Several nearby cities had soldiers deployed nearby in case they needed to be evacuated.
• Groves advised Governor, John J. Dempsey of New Mexico, that that in the case of an emergency, a state of martial law could be necessary to be enforced there. Groves was already nervous about the well-being of Amarillo, Texas, an urban center of seventy thousand residents that was just about 300 miles away. The Army Public Relations Department was prepared with depressing justifications in case a catastrophe occurred and lives were lost.
• On July 16, the test’s planned 4:00 AM start time had to be postponed due to rain. Hubbard’s team eventually came to a decision that the ideal weather would only be prevalent between 5:00 and 6:00 AM. Groves was infamous for saying that he would “hang you” if Hubbard was wrong. Luckily for Hubbard, the sky started to gradually clear.
• Since the weather prediction appeared good, the scientists and the military established camp a few hours before the test’s rescheduled 5:30 AM detonation. The shelters 10,000 yards to the north, west, and south of the tower were the closest. Soldiers resided in these bunkers, which were beneath the supervision of Manhattan Project researchers who were researching the effects of radiation. Twenty kilometers away, in a tower on Compania Hill, the project supervisors could see the shelter.
• At 5:29:45, Gadget detonated with an explosion that was 15–20 kilotons more powerful than the Little Boy bomb introduced in Hiroshima. Everything went smoothly to plan in the end after years of hard struggle. The test produced more TNT than had been anticipated, which was the opposite of what was expected. The complex system of conductors, switches, and detonators created a previously unheard energy explosion.

Atomic Bombings of Hiroshima and Nagasaki: On August 6 and 9, 1945, The United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki respectively. This was the first time that atomic weapons were used in battle. The Atomic bombings of Hiroshima and Nagasaki in 1945 claimed the lives of tens of thousands of people, and numerous more would eventually die from radiation sickness. The Japanese government declared on August 10, the day after Nagasaki was bombed, that it would accept the conditions for the Allies’ surrender as forth in the Potsdam Declaration.

In this article, you will read about the atomic bombings of Hiroshima and Nagasaki, the history of the bombings, the aftermath, and the Manhattan Project which had a major role in the the atomic bombings.