International space law is a body of law which concerns activities in space, usually defined for legal purposes as the lowest point from which objects can orbit the Earth and beyond. This area of the law has its origins in the 1950s, when many nations began discussing the possibility of space exploration and the need to regulate the use of space. There are several international treaties concerned with space law that signatories must abide by, and many nations have passed some laws of their own which dictate what their citizens can do in space.
One of the key bodies involved in international space law is the Committee on the Peaceful Uses of Outer Space, which is part of the United Nations (UN). An important aspect of space law is the belief that space is available for everyone to use and that no one person or country should be allowed to claim or control part of space. International space law covers topics like arms control, assistance to astronauts, regulation of objects in space, and liability incurred when objects in space collide with each other or fall to Earth.
As a general rule, individual astronauts and companies are subject to the rules of their own nations, even when in space, and must also abide by space law. Under the terms of international space law, objects launched into space belong to their original owners, and the owners retain liability for those objects whether they are in space or on Earth. Likewise, when astronauts return to Earth, they are considered to "belong" to their countries, and they must be returned home promptly if they are forced to land in a foreign country.
As human uses of space have expanded, so has the body of international space law. Some of the law is highly nebulous, the result of the need to keep terms vague in order to encourage countries to become signatories to treaties and agreements concerning space. As with other areas of the law, international space law is also impacted by case law, with the outcomes of individual cases involving space being added to the body of law. Precedent-setting cases can establish new ways of approaching many different situations which may arise in space or which may surround space-related events and issues.
Theorizing about space law has also been an important part of the science fiction genre. Authors curious about the future of space exploration and the ways in which space will be used by future generations have explored a number of possible ways in which this area of the law may evolve.