The Manhattan Project

.. neral Groves had built a half-billion dollar secret factory in Oak Ridge, Tennessee. It was only producing tiny amounts of pure U-235, and Oppenheimer was informed he could count on enough of it for just one bomb by mid-1945. Groves other secret factory, near Hanford, Washington, was working to produce the other fissionable material, P-239. By 1945 it was estimated that Hanford was producing enough of the plutonium for multiple bombs.

Everyone was absolutely convinced that the detonation of a uranium bomb by the gun-method would work. However, by early 1944, it became increasingly obvious that this would not work with the plutonium bomb. This meant that Neddermeyers implosion method would have to be used. The problem with this, though, was that the plutonium bombs technology was much newer and much more advanced, so it absolutely had to be tested before it was used. And that meant that someplace in America had to be found to test the most potentially awesome bomb that the world had ever seen.

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The search for a suitable site to test the bomb began in May of 1944. The requirements were very strict: it had to be relatively flat, both to minimize the effects of the terrain on the bomb and to maximize the opportunities for a variety of experiments and observations. The weather had to be basically good. The site had to be isolated from any centers of population, yet close enough to Los Alamos to allow for the easy movement of men and equipment. That September, an area called the “Jornada del Muerto was finally settled on.

It is a stretch of desert lying between present-day Socorro and El Paso. It is bounded by the San Andres and San Mateo mountains. The sandy soil supports only sparse vegetation, and the summer temperatures often reach well over 100 degrees Fahrenheit (38 degrees Celsius). Once the war started, the government leased several hundred miles to be used for test bombing, and this test site became known as Trinity. Construction on this site was full steam ahead by November.

But, the construction company did not even know what they were working on. The workers concluded that, based on the fact they were building enormous concrete bunkers and reinforced steel towers, the area had to do with powerful explosives. Mid-July was not an ideal time for a test-bombing, as temperatures were often well over 100 degrees Fahrenheit, and severe thunderstorms were common. The weather was not the only problem the scientists encountered. The plutonium for the bomb did not arrive at Los Alamos from Hanford until May 31, and prior to that no one had even seen the artificial element. Up to that day, the bomb was all theory, existing only in the notes and calculations of the scientists. The plutonium core finally arrived as a syrupy nitrate, but still had to be purified and transformed into metal.

Two thirteen-and-a-half pound (6 kg) spheres, which had to be exactly identical and completely smooth, were to be formed from the metal and used in the core of the bomb. On July 12, the plutonium core was taken to Trinity. It was in a rubber-studded case in the backseat of an old army sedan, while up ahead a carload of armed guards cleared the way, while assembly specialists brought up the rear. On July13, the core was driven to the base of the 100 foot (30 m) tower at Trinity for the final assembly. The heat caused the plutonium core to expand, though, and there was a momentary panic when it would not click into its base. It finally cooled down and was then clicked into place, then hoisted to the top of the tower with a power winch.

The test date was scheduled for 4:00 A.M. on July 16, 1945, but that time was scratched because of approaching thunderstorms. At 2 A.M., Groves and Oppenheimer drove from their observation post to a much nearer one and rescheduled the test for 5:30 AM., weather permitting. Shortly after 3 that morning the rain stopped, and at about 4 the clouds parted and the winds began to die. At approximately 5 A.M., explosives expert George Kiatkowsky checked the towers electrical connections, threw the final switches, and drove five miles away to the South 10,000 control bunker. The countdown began at zero minus twenty-minutes.

The two-minute warning rocket failed, but the one-minute warning rocket and sire went off as planned. At 5:29 A.M., Sam Allison, the University of Chicago physicist who had conducted the countdown, yelled “Zero!!” Nothing happened. Then the sky suddenly ignited with an explosion of such a magnitude the world had never seen before. The flash, as bright as twenty suns, was seen in three states and threw up a multicolored mushroom cloud that surged 38,000 feet (11,582 m) into the atmosphere in seven minutes. The heat at the center of the blast was as great as that at the center of the sun.

Where the fireball touched the ground there was a crater a half-mile across, and it had fused the sand into a greenish-gray glass. Every living thing within a radius of a mile–plants, snakes, ground squirrels, lizards, and even ants–was obliterated. The test that changed the world was a complete success, and said by Oppenheimer to be “technically sweet.” The Manhattan Project all but ended that day, after the bombs successful detonation. Although there was still months of work to be done at Los Alamos, the real action moved elsewhere. As the Trinity test was being planned, so too was the bombing of Japan.

After Trinity the center of operations had moved to the island of Tinian, part of the Marshall Islands chain in the Pacific Ocean. During the summer of 1945 the planners drew up a list of potential targets for the bomb–Hiroshima, Kokura, Niigata, and Nagasaki. Hiroshima was moved to the top of the list because it had a large military depot, an industrial area, and was surrounded by hill which would help focus the blast. It was also the only place on the list that did not contain Allied prisoner-of-war camps. On July 26, President Truman issued what he called the Potsdam Declaration on behalf of himself, the president of Nationalist China, and the Prime Minister of Great Britain.

There was no mention of the atomic bomb, but Truman included the threat of”utter destruction.” As was expected, Japan rejected President Trumans declaration, so the plan to drop an atomic bomb on Japan continued. The plan called to first drop the reliable Little Boy uranium bomb. That would be followed by the dropping of the plutonium based Fat Man bomb on a second, undecided target. The plans also called for the production and use of as many plutonium bombs as necessary to bring about the surrender of Japan. More and more bomb-making materials were arriving at Tinian everyday, and B-29s had already been modified to carry the new weapon. Crews had been chosen and specially trained, though they were not actually told what sold sort of weapon they were going to drop until the very last minute.

The plane that was going to carry the bomb had been known only as B-29 number 82. The day the bomb was loaded the mission pilot, Paul Tibbets, had his mothers given names “Enola Gay” painted on the fuselage. The original plan called for the bomb to be fully armed at takeoff, but Captain William “Deke” Parsons had seen too many B-29s roll off the runway and catch fire. He was afraid that if that happened to Enola Gay, it could trigger the bomb and blow up half of the island. This worry made him decide to arm the bomb after takeoff.

The “Enola Gay” had been flying toward Japan for several hours before the bomb was fully armed. The bomb bay doors swung open over Hiroshima on August 14, at 8:15 A.M. local time, and, lightened by nearly 10,000 pounds (4,540 kg) the plane lurched upward. There was what seemed like a long delay and suddenly a bright light filled the plane. First one shockwave, then another rattled it. Groves phoned Oppenheimer at Los Alamos to tell him the bomb had gone off “with a very big bang.” Oppenheimer was not as excited as Truman, but he was both pleased and happy. The Japanese, both literally and figuratively, did not know what had hit them, but before they could find out, they were hit again.

On August 9, Fat Man, the plutonium bomb, was dropped over the city of Nagasaki. More bombs were ready to go, but Washington decided that they may not be necessary, as it looked like Japan was ready to surrender. On August 15 the Japanese emperor went on the radio to announce that the government had already notified the Allied powers of its surrender. It also happened to be the first time that the Japanese people had ever heard their emperors voice. The war was finally and completely over.

It was not until the bombing of Hiroshima that the entire world learned of the existence of the atomic bomb. For most Americans it came as wonderful news. However, to most people, the atomic bomb seemed like nothing more than a big bomb–they had no idea of its destructive force, nor of the radiation. Not even the scientists knew of the amount of radiation that would be released. They knew that some dangerous radiation would be released by the blast, but the effects of it were far from worse than anyone had imagined. Postwar censorship kept many of the grisly details away from the American people for at least a year.

And the worst effects of the radiation–the leukemia, the cancer, the genetic damage–did not really show up for several years. The atomic bomb was not just a bigger bomb; it totally changed the face of warfare. Bibliography Bibliography “Atomic Bomb.” Encyclopedia Brittanica: Science and Tecnology Illustrated. 1984. “Atomic Bomb.” McGraw-Hill Encyclopedia of Science and Technology.

1992. Cohen, Daniel. The Manhattan Project. Brookfield, Connecticut: The Millbrook Press, 1999. Kunetka, James W. City of Fire: Los Alamos and the Birth of the Atomic Age, 1943-1945.

Englewood, New Jersey: Prentice-Hall, Inc., 1978.