🔗 Starfish Prime, outer space nuclear test

🔗 United States 🔗 Spaceflight 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 United States/Military history - U.S. military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Micronesia 🔗 Micronesia/Johnston Atoll

Starfish Prime was a July 9, 1962, high-altitude nuclear test conducted by the United States, a joint effort of the Atomic Energy Commission (AEC) and the Defense Atomic Support Agency. It was launched from Johnston Atoll and was the largest nuclear test conducted in outer space and one of five conducted by the US in space.

A Thor rocket carrying a W49 thermonuclear warhead (designed by Los Alamos Scientific Laboratory) and a Mk. 2 reentry vehicle was launched from Johnston Atoll in the Pacific Ocean, about 900 miles (1,450 km) west-southwest of Hawaii. The explosion took place at an altitude of 250 miles (400 km), above a point 19 miles (31 km) southwest of Johnston Atoll. It produced a yield equivalent to 1.4 megatonnes of TNT. The explosion was about 10° above the horizon as seen from Hawaii, at 11 PM Hawaii time.