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, the Outer Space Treaty is basically humankind’s first foundation of international space law. It came about in the 1960s during both the Cold War and the space race, when the United States and the Soviet Union agreed to refrain from introducing weapons of mass destruction into outer space. The treaty was put into force in 1967 after signatures from the US, the UK and the Soviet Union, and 102 countries have signed the treaty to date. You can read it in full here. At the moment, it mainly limits the use of celestial bodies (such as the Moon) to peaceful purposes: no country can place weapons of mass destruction on them, nor establish military bases or conduct any kind of military manoeuvres. Outer space, the treaty states, shall be free for exploration and use by all countries, for the benefit and interest of the world, and so no country can own a celestial body or claim it as a resource. Space is “not subject to national appropriation by claim of sovereignty,” because it is the Common heritage of mankind, just as astronauts “shall be regarded as the envoys of mankind.” These are beautiful concepts, like a child’s ideas are beautiful—mankind is still young, and the treaty is a remarkable milestone as we begin to open our eyes to the universe.