Outer Space Treaty Law and Legal Definition

The Outer Space Treaty, formally known as the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, is a treaty that forms the basis of international space law. The treaty was adopted by the General Assembly in 1963. The Treaty was opened for signature by the three depository Governments (the Russian Federation, the United Kingdom and the United States of America) in January 1967, and it entered into force in October 1967.

The Outer Space Treaty provides the basic framework on international space law, including the following principles:

  • the exploration and use of outer space shall be carried out for the benefit and in the interests of all countries and shall be the province of all mankind;
  • outer space shall be free for exploration and use by all States;
  • outer space is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means;
  • States shall not place nuclear weapons or other weapons of mass destruction in orbit or on celestial bodies or station them in outer space in any other manner;
  • the Moon and other celestial bodies shall be used exclusively for peaceful purposes;
  • astronauts shall be regarded as the envoys of mankind;
  • States shall be responsible for national space activities whether carried out by governmental or non-governmental activities;
  • States shall be liable for damage caused by their space objects; and
  • States shall avoid harmful contamination of space and celestial bodies.

Ninety-eight States have ratified, and an additional twenty-seven have signed the Outer Space Treaty as of January 1, 2008.