Partial Nuclear Test Ban Treaty
The signing of the Partial Nuclear Test Ban Treaty in 1963 and the Outer Space Treaty in 1967 prevented future exploration of the concept of detonating a nuclear device on the Moon. By this time, both the United States and the Soviet Union had performed several high-altitude nuclear explosions, including those of Operation Hardtack I, Operation Argus, Operation Dominic I and II, and The K Project.