The concept of “very high altitude” refers to the gaseous layers above the troposphere, surrounding the Earth and comprising the stratosphere, the mesosphere and the lower thermosphere. Although this area is not governed by any treaty, it is not a “lawless” zone. It is a fact that a state can exercise territorial sovereignty up to an altitude of 20 km above sea level. The Outer Space Treaty, on the other hand, only covers human space activities above 100 km (Kármán line).
Was the Chinese stratospheric balloon shot down by the United States on 3 February 2023 illegally encroaching on US airspace or was it operating in a lawful area for the purpose of carrying out its missions? Did the aerostat in question pose a threat to the security of the United States and its population? Was its destruction required? And what will be the consequences of this incident for future Sino-American relations, which were thought to have been revived since the meeting between President Biden and President Xi Jinping at the G20 summit in Indonesia? These are the questions we will try to answer in this e-Note.
(Only available in French)
Research lines: Defence capabilities and technologies ; Eurasia
Les enjeux juridiques et stratégiques insoupçonnés de la très haute altitude
© Navy Petty Officer 1st Class Tyler Thompson
Source image : https://www.defense.gov/Multimedia/Photos/igphoto/2003157679/