Dominic 'Androscoggin' atom bomb test, 1962. The US conducted a series of 31 atom bomb tests in 1962 under the codename Operation Dominic. This fireball is from 'Androscoggin', one of the tests carried out at Johnston Island, Johnston Atoll, in the central Pacific Ocean. These tests were carried out between May and October of that year. These tests were among the last atmospheric tests carried out by the USA, with the Limited Test Ban Treaty being ratified in 1963. This test, codenamed Androscoggin, took place on 2 October 1962. The 27th test in the series, it was an airdrop with a yield of 75 kilotons.