At 5:29:45 a.m., as part of The Trinity Test, Gadget is detonated in Alamogordo, NM in the first atomic explosion in history. The explosive yield is 20-22 Kt (initially estimated at 18.9 Kt), vaporizing the steel tower.
1945: Ending the War
1945: Ending the War
Gadget is hoisted to the top of the 100 foot test tower, and the detonators are installed and connected. Final test preparations begin. Meanwhile, Little Boy bomb units, accompanied by the U-235 projectile, are shipped out of San Francisco on the USS Indianapolis for Tinian Island. Lastly, the only full-scale test of the implosion lens system (before Gadget) is conducted. Initial analysis indicates failure. Bethe later corrects mistaken calculations and finds that the measurements are consistent with optimum performance.
The plutonium core and the Gadget components leave Los Alamos, NM for the test site separately. Assembly of Gadget begins at 1300 hours on July 13. Assembly of Gadget's explosive lens, uranium reflector, and plutonium core is completed at Ground Zero at 1745 hours.
Assembly of Gadget, the first atomic bomb begins. Also, Japanese Foreign Minister Shigenori Togo cables Ambassador Naotake Sato in Moscow advising him to explore using the USSR as an intermediary in surrender negotiations.
The best available lens castings are selected for The Trinity Test.
Explosives lens casting for The Trinity Test completed.
Machining of the uranium reflector for The Trinity Test completed.
Casting of the U-235 projectile for Little Boy is completed.
Final preparations begin at the New Mexico test site, the Jornada del Muerto at the Alamagordo Bombing Range, for the first atomic bomb test, code named Trinity. The date is set for July 16. Jumbo is not used in the test, since plutonium delivery schedules make recovery of active material (in the event of a fizzle) less important.
Curtis LeMay estimates that the Twentieth Air Force will finish destroying the 60 most important cities in Japan by Oct. 1. Also, the T-5 group in the Los Alamos T (Theory) Division estimates The Trinity Test explosion yield at 4-13 Kt.