FROM AIRSPACE TO OUTER SPACE: THE LEGAL GREY ZONE OF SUBORBITAL FLIGHTS

Suborbital flights journeys that climb above the bulk of the atmosphere but do not achieve orbital velocity occupy a region that international law has never defined. Air law, built on the Chicago Convention’s principle of complete and exclusive sovereignty over national airspace, and space law, built on the Outer Space Treaty’s principles of freedom and non-appropriation, rest on contradictory premises, yet neither instrument identifies where one regime ends and the other begins. This paper examines how the absence of a legal boundary between airspace and outer space creates uncertainty for suborbital operations in five areas: sovereignty and overflight, registration, liability, the status of passengers, and air traffic integration. It surveys the spatialist and functionalist positions in the delimitation debate, evaluates domestic responses in the United States, the United Kingdom, Australia and India, and argues that a purpose-based hybrid regime, developed jointly by ICAO and UNCOPUOS and supported by harmonised national legislation, offers a more workable solution than the elusive search for a single altitude line.