Nuclear technology the element plutonium possesses an isotope that is sufficiently unstable for this process to be usable. Terrestrial plutonium does not currently occur naturally in sufficient quantities for such use, so it must be manufactured in a nuclear reactor. Ultimately, the Manhattan Project manufactured nuclear weapons based on each of these elements. They detonated the first nuclear weapon in a test code-named "Trinity", near Alamogordo, New Mexico, on July 16, 1945. The test was conducted to ensure that the implosion method of detonation would work, which it did. A uranium bomb, Little Boy, was dropped on the Japanese city Hiroshima on
Mark 15 nuclear bomb was the first US thermonuclear bomb airdrop test. The Mod 3 also appears to have had a 3.8 megaton yield. A missile warhead variant of the Mark 15, the W15 Warhead, was an ongoing project in the mid 1950s. It was canceled in early 1957. Before cancellation, it had been intended for use on the SM-62 Snark missile. Instead, the Snark ended up using the W39 (see below). The W39 nuclear warhead and B39 nuclear bomb used a common nuclear "physics package" which was derived from the Mark 15. The experimental W39 devices were initially tested as the TX-15-X3 (which