New Types of Higher Airspace Flight Operations and Their Legal Challenges

The absence of an internationally recognised legal boundary between airspace and outer space has long been acknowledged but has seldom resulted in practical operational issues. This was largely due to the clear technological distinctions between air and space activities. However, advancement in materials, propulsion and manufacturing technologies now enable operations in the transition zone between conventional aerial flight and spaceflight. It is only a matter of time before activities in this specific region around our Earth will be facing legal challenges. The lack of clear legal delimitation between outer space and airspace does not stem from an absence of natural phenomena that could define such a boundary but rather the existence of multiple valid criteria, each of which has counterarguments. To address this issue, it is proposed that an intermediate or transition zone be codified to establish a secure legal framework for these emerging higher airspace operations. Such a framework would provide legal security for investors, while fostering research, development and innovation. Although this measure would not resolve all legal ambiguities concerning spaceflight, it could alleviate challenges faced by developers and operators of stratospheric, mesospheric, and lower thermospheric flight technologies. This article explores practical examples and the technological contexts of these operations to inform developers about regulatory developments.