Operation Fishbowl and Starfish Prime

Operation Fishbowl was a series of high altitude nuclear tests launched on Thor rockets from Johnston Island in the Pacific in 1962, as part of the larger Operation Dominic. Its biggest shot, Starfish Prime, detonated a 1.4 megaton warhead about 400 kilometers above the ocean on July 9, 1962. In Hawaii, some 1,450 kilometers away, the night sky glowed green and red for minutes. The blast's electromagnetic pulse, a surge of energy from the explosion, knocked out a few hundred streetlights in Honolulu, set off burglar alarms and disrupted a telephone link. Electrons injected into Earth's magnetic field formed an artificial radiation belt that damaged or destroyed several satellites, including Britain's Ariel 1 and the communications satellite Telstar 1, launched the day after the test.¹²

The tests answered military questions about whether nuclear blasts in space could blind radar, black out radio or destroy incoming warheads, at a time when the Soviet Union was running similar tests. Fishbowl had failures: two launches were destroyed on the pad or soon after takeoff, scattering radioactive debris on Johnston Island. The tests were announced in advance, and in Honolulu some hotels held rooftop viewing parties. Concern over the effects helped push the Partial Nuclear Test Ban Treaty of 1963, which banned nuclear explosions in space.¹²