Outer Space Treaty, 1967

The Outer Space Treaty, 1967 establishes the basic legal framework for activities in outer space. Its non-appropriation principle prevents any state from treating outer space, the Moon, or another celestial body as its sovereign territory, while still permitting exploration and use.

Core prohibition on appropriation

Under Article II, outer space, including the Moon and other celestial bodies, is not subject to national appropriation through a claim of sovereignty, use, occupation, or any other means.

• A state cannot annex a celestial body or claim territorial sovereignty over any part of it.
• Occupation, settlement, or prolonged use cannot by itself mature into territorial title.
• Under Article I, exploration and use must remain free for all states, with free access to all areas of celestial bodies.

Application to governmental and private activities

The prohibition cannot readily be avoided by acting through private entities. Under Article VI, states bear international responsibility for national space activities conducted by governmental or non-governmental entities, and private activities require authorization and continuing supervision.

• A state must ensure that its national actors conduct their activities consistently with the treaty.
• Under Article VIII, a registry state retains jurisdiction over its space objects and personnel, but this does not create sovereignty over the surrounding celestial territory.

Permitted use and unresolved boundary

The treaty distinguishes prohibited territorial appropriation from permitted exploration and use. States may conduct scientific investigations, establish equipment, and retain ownership of space objects without acquiring title to the celestial surface beneath them.

• The treaty does not expressly determine whether extracted space resources may become property, so the legal treatment of resource extraction remains debated.
• Any use must coexist with other states' treaty rights rather than create an exclusive territorial claim.