STARFISH PRIME, was one of the high-altitude nuclear tests in the Operation Fishbowl series conducted in the Pacific Proving Ground in 1962. It was launched in the Johnston Island area to an altitude of about 400 kilometers by a Thor rocket and had a yield of 1.4 megatons.
The test evaluated the capabilities of an antiballistic missile to operate in a nuclear environment and the vulnerability of a U.S. reentry vehicle to survive a nearby nuclear blast. It also provided information on the ability of a U.S. radar system to detect and track reentry vehicles. Another goal was to discern the effects of a high-altitude blast on command and control systems, which were shown to be vulnerable in earlier high-altitude tests. The final goal was to obtain information on the feasibility of testing in outer space.