The U.S. Nuclear Weapons Cost Study Project was completed in August 1998 and resulted in the book Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940 edited by Stephen I. Schwartz. These project pages should be considered historical.
Workers with the Manhattan Engineer District gently carry the plutonium core for the world’s first atomic bomb—in the form of two small hemispheres—into the McDonald Ranch house (near the Trinity test site) for assembly, July 12, 1945
Herb Lehr, a member of the Manhattan Project’s Special Engineering Detachment, holding the assembled plutonium core for the world’s first atomic bomb in a special shock-absorbing case about 6:00 p.m. on July 12, 1945. The core was about the size of an orange and weighed some 13.5 pounds (6.1 kilograms)
Physicist Norris Bradbury and Boyce McDaniel (part of the Manhattan Project’s Special Engineering Detachment) stand at the top of a 100 foot (30.5 meter) tower after helping to assemble the world’s first atomic bomb on July 15, 1945, one day before the Trinity test. Detonators and cables cover the surface of the handmade device, nicknamed the “Gadget.”
The “Gadget” was detonated at 05:29:45 mountain war time on July 16, 1945 at the Trinity site (now part of the White Sands Missile Range, New Mexico). The device had a yield of 23 kilotons ± 3 kilotons.
Credit: Los Alamos National Laboratory