Trinity Site

On the White Sands Missile Range, the world's first nuclear device exploded on July 16, 1945. When the Manhattan Engineer District was formed to develop an atomic bomb in the shortest possible time, the problems confronting its scientists and engineers were seemingly almost insurmountable. As the project moved closer to fulfillment, it became obvious that the device would have to be tested before it was tried in combat. The site chosen for the test was a portion of the Alamogordo Bombing Range in the bleak and barren Jornada del Muerto in Socorro County. The code name "Trinity," was chosen for the test by Dr. J. Robert Oppenheimer, director of the Manhattan Project. Work at the site began late in 1944, and, by May 1945, preparations were completed for a test shot of 100 tons of high explosive—its purposes being to provide data for the calibration of instruments for blast and shock measurements and to serve as a dress rehearsal for functioning of the test organization. The test was held on May 7, resulting in a memorable sight eclipsed only by the atomic explosion two months later. The final test was set for 4 a.m. on Monday, July 16. The bomb was assembled and placed on a 100-foot tower, and observers took their places in bunkers 10,000 yards to the south, west, and north of Ground Zero. Rain delayed the detonation for one and one-half hours, but at 5:29:45 a.m. the blast came. The world had entered a new era. The Ground Zero area at the Trinity Site is marked by a lava stone monument enclosed in a large fence circle. Six of the concrete bunkers and structures at the MacDonald Farm, where scientists assembled the bomb, and at Camp Trinity, the base camp, still remain. The site is closed to the public, as it is still within the White Sands Missile Range.

History

The Los Alamos Project of the Manhattan Engineer District of the War Department began in 1943 with the purpose of the development and final manufacture of a nuclear instrument of war. Among the projects the Los Alamos scientists developed, the implosion method, in which a sub-critical mass of plutonium is compressed to super-criticality by high explosives, had reached the stage by late 1943 where a test of an implosion device was essential for further progress, even though it meant the depletion of the Nation's entire supply of plutonium. The first step in the test explosion was to develop a means of preserving the invaluable plutonium in the case of an unsuccessful test. The result of this work was "Jumbo," a 25-foot-long, 214-ton steel vessel that was designed to contain the blast. Although the availability of plutonium increased, and confidence in the bomb increased as well, Jumbo was transported to the test site on the Alamogordo Bombing Range in an unprecedented succession of engineering feats, but the vessel was never used. Through the spring and summer of 1944, the search went on for a suitable test site. By late summer, the choice was narrowed down to the part of the bombing range just to the north of Mockingbird Gap. This site already in the possession of the Government was suitably flat and dry, although windy, and was close enough (300 miles) to Los Alamos but far enough from the nearest town (27 miles). In 1944, the Trinity base camp was built by the Army and occupied by a detachment of military police. By the summer it was housing more than 200 scientists, soldiers, and technicians. Through the spring and summer of 1945, the men at Trinity were feverishly involved in necessary preparations, such as stringing the hundreds of miles of communication wires, building the instrumentation and control bunkers, and assembling the apparatus for the trial blast. This trial blast of 100 tons of high explosives was necessary for the calibration of recording instruments and was carried out successfully on May 7, 1945. On July 13, the final components of the atomic bomb, "the Fat Man," were delivered from Los Alamos to the assembly site at the deserted MacDonald Ranch, which had been converted into the assembly laboratory. The bomb was assembled without its detonators by late afternoon, and early the next morning, it was raised to its position on the top of the 100-foot steel tower. The detonators were added that afternoon, and for the next day, the preparatory instrumentation was carried out. By the pre-dawn of July 16, all was ready. However, the ominous thunder and lightning of a coming storm necessitated a 90-minute postponement. Near 4 a.m., the light rain stopped and the weather cleared. At 5:29:45 a.m. there occurred the detonation of the world's first nuclear fission bomb, with an estimated force equivalent to 20,000 tons of TNT, far more powerful than was expected. Through the day of July 16, cars of weary, excited men headed back to Los Alamos to prepare for the new Fat Man which was dropped on Nagasaki, Japan, on August 9. Japan surrendered five days later.