Space law is a branch of international law concerned with the regulation of activities in outer space. Man's ability to penetrate beyond the earth's atmosphere, demonstrated in 1957, gave rise to intense speculation about the nature of the legal order under which outer-space activities would take place. From the outset, statesmen and scholars agreed that the bulk of the pertinent rules of international law, which govern relations between nations on earth, would apply to human activities beyond the atmosphere- that, in fact, there was no "legal vacuum" in space. Space law has been modeled in part on the agreements concerning the peaceful use of the oceans and Antarctica.
Most of the present pattern of space law originated with UN General Assembly resolutions, adopted unanimously in 1961 and 1963, and the 1963 Nuclear Test Ban Treaty. The UN resolutions called for international cooperation in outer space; the treaty prohibited nuclear testing there. Answers to many legal questions were provided by the general outer-space treaty of 1967, a 1968 agreement on astronauts, and a 1972 treaty on liability.
Broadly paraphrased, the nations are in agreement that each has equal legal rights of access to outer space for peaceful activities; that no nation may claim sovereignty in outer space or to a celestial body; that international law, including the UN Charter, applies to activities in space; and that nuclear testing, the stationing of nuclear weapons in space, and the placing of military bases on celestial bodies are barred. The nations have also agreed that astronauts and space vehicles remain under the jurisdiction of their state of nationality and that astronauts are to receive every assistance in the event of accident.
States are to consult together before undertaking potentially hazardous activities. In addition, states are generally responsible for national spacecraft and have agreed to accept absolute responsibility for damage caused by their space vehicles to persons, property, or aircraft on the earth's surface, including airspace, and to accept liability, based on fault, if another spacecraft or its occupants are harmed. Thus, an embryonic but rather extensive regime for cooperative, peaceful space activities exists.
A number of legal questions remain, including a definition of the outer limit of national airspace, in which states have absolute sovereignty. The U.S.-Soviet contention over the flying of military "spy" satellites largely disappeared by the late 1960 s, when it became clear that both states were using them. But the development by the United States of civilian resource-sensing satellites raised questions about the right to "view" possibly unwilling nations and about the processing and "ownership" of such information.
Questions about a specific right to use and even to "mine" areas of the moon and about national (or private) claims of ownership of materials brought from the moon have arisen. Future questions will have to do with traffic control, direct broadcasting or use of space "areas" especially suitable for communications satellites, access by corporations, "cluttering" and "pollution" of space, and other matters not readily foreseeable.