The Outer Space Treaty Took Effect in 1967

On October 10, 1967, the Outer Space Treaty entered into force. It is the foundation of space law. It forbids countries from placing nuclear weapons or any other weapons of mass destruction in orbit around Earth, and it declares that space and celestial bodies are exempt from national claims of ownership.

That means no nation can own the Moon, and planting a flag there does not change who controls the ground. The treaty was written when both the United States and the Soviet Union had rockets able to put nuclear weapons in orbit. As of June 2024, 115 countries were parties to it.