US performs nuclear test at Christmas Island (atmospheric)

High-altitude nuclear explosions are the result of nuclear weapons testing within the upper layers of the Earth's atmosphere and in outer space. Several such tests were performed at high altitudes by the United States and the Soviet Union between 1958 and 1962. The Partial Test Ban Treaty was passed in October 1963, ending atmospheric and exoatmospheric nuclear tests. The Outer Space Treaty of 1967 banned the stationing of nuclear weapons in space, in addition to other weapons of mass destruction. The Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all nuclear testing; whether over- or underground, underwater or in the atmosphere, but has yet to enter into force as it has not been ratified by some of the states party to the Treaty.