§ Lord Hill-Norton
asked Her Majesty's Government:
Whether they recognise any definitions of the terms "airspace", "outer space", "deep space" and "interstellar space"; whether they will detail such definitions; and whether these are the same definitions as used by the United States Government. [HL3311]
§ The Parliamentary Under-Secretary of State, Department of Trade and Industry (Lord Sainsbury of Turville)
Her Majesty's Government recognise and use the term "airspace". The principle of airspace sovereignty is defined in the Chicago Convention on International Civil Aviation (1944), which states that a country has complete and exclusive sovereignty over the airspace above its territory, including its territorial sea. This airspace starts immediately above the surface of the earth.
There is no internationally agreed definition of where "outer space" starts. The most commonly used boundary between airspace and outer space is functional. This means, for instance, that the launching of satellites or other space objects is deemed to be an "outer space" activity and that the flight of aircraft is considered to be an activity in airspace. The use of "outer space" is governed by the United Nations Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and other Celestial Bodies (known as the Outer Space Treaty, 1967) which covers all activity beyond sovereign airspace. Both the UK and the US have ratified the Outer Space Treaty and UK legislation regulating such activity (the Outer Space Act 1986) is based on its principles.
"Deep space" and "interstellar space" are terms sometimes used by space scientists and astronomers. "Deep space" is a phrase often used to describe space missions to other planets, beyond the combined gravitational field of the earth and the moon. "Interstellar space" is not commonly used but could, for example, denote the space between stars within a galaxy.