Outer Space Treaty (1967)

The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space (1967) — commonly called the Outer Space Treaty — establishes the foundational legal framework for all activities in space. Key principles: space is free for exploration by all states; no nation can claim sovereignty over celestial bodies; nuclear weapons and WMDs cannot be placed in orbit; states bear international responsibility for national space activities (including private companies); states are liable for damage caused by their space objects; and astronauts are "envoys of mankind." Over 110 nations are parties, including all major spacefaring nations.