Questa tested a warhead meant for two missiles that ended up serving one of them briefly and the other not at all. Dropped from a B-52 over the Pacific about 24 kilometres south of Christmas Island on 4 May 1962 and detonated at around 1,600 metres, the 670-kilotonne shot was a Los Alamos test of the W-59 — a warhead competing to arm the Minuteman intercontinental missile, and also intended for Skybolt, an air-launched ballistic missile then being developed to be carried and fired from bombers.Neither purpose went as planned. On this shot the W-59 fell well short of its mark — about 670 kilotonnes against an expected megatonne — its full yield reached only in a later test. And Skybolt, the airborne missile it was partly built for, was cancelled by the United States that December: a decision that jolted Britain, which had been relying on the weapon to keep its own bomber-borne deterrent alive, and pushed London toward buying the submarine-launched Polaris instead. As for the Minuteman, the W-59 lost the contest — its rival, the Livermore W-56, carried a higher yield and was chosen for the improved Minuteman II.About a hundred and fifty W-59s were built, armed the first Minuteman missiles for a few years, and were withdrawn by the end of the 1960s. Questa was one of the earliest shots of Operation Dominic, the crash series the United States rushed into the Pacific in 1962 after the Soviet Union broke a three-year testing pause — the last and largest of the American atmospheric programmes, ended within a year by the 1963 Partial Test Ban Treaty.