space law, agreements governing the exploration and use of outer space, developed since the first launching (1957) by humans of a satellite into space. Space law, an aspect of international law, has grown under the aegis of the United Nations. A 1963 UN declaration stated that the exploration and use of outer space would be for the benefit and in the interest of all people; that no sovereignty could be claimed in space; that objects and persons launched into space would be returned promptly and safely if they landed in a foreign country; and that nations launching objects would be responsible for damages caused by them. In 1967, a general treaty embodying these principles and adding a prohibition on the military use of space and a provision for the inspection of installations on celestial bodies went into effect. A UN treaty on use of the moon's resources was drafted in 1979. The boundary between airspace (see air, law of the), which is subject to sovereignty, and outer space remains an object of discussion. Some favor definitions based on the composition of the atmosphere. Others favor a functional approach; thus, if commercial airlines use a particular layer of the atmosphere, it is to be considered airspace.