Outer Space (Delimitation)

Outer space refers to the region or expanse that exists beyond the Earth and between celestial bodies. There is no international consensus as to where airspace ends and outer space begins, particularly since these terms have not been properly defined in international law. Some experts have argued that space extends down to 100 km above sea level. This is so because at their lowest orbital point, or perigee, some satellites have operated at around 100 km (328,000 feet or 62 miles). This approximate altitude is known as the von Kármán line, commonly referenced as the point for air versus space demarcation and the point at which it is believed an aircraft would have to reach orbital velocity to produce enough lift to remain aloft. There are others, however, who argue that the delimitation should be lower, establishing the delimitation altitude at 80 km above sea level in order to account for suborbital spacecraft as well as hybrid aerospace vehicles capable of operation both in airspace and outer space.

There are currently two main schools of thought that have emerged with the objective of answering the delimitation question. On the one hand, ‘spatialism’ essentially argues for a fixed line, at a set altitude, for the division of airspace and outer space. On the other hand, ‘functionalism’ focuses on the nature of the craft in question: the applicable law will depend on the functions it serves.

It should be noted that some domestic space law definitions establish a specific delimitation for the purposes of licensing.