2.2 What is a ‘celestial body’?
What constitutes a celestial body is not defined in the OST, nor any other international framework. At a glance, there are two interpretations: one broad, referring to any natural body in outer space, and another more restrictive, suggesting size or significance might play a role. The dictionary offers a wide definition, considering a celestial body as ‘any unit of matter in the universe, like planets or stars, for astronomical study’.(1) The Merriam-Webster dictionary describes a celestial body as “an aggregation of matter in the universe (such as a planet, star or nebula) that can be considered as a single unit (as for astronomical study)”; https://www.merriam-webster.com/dictionary/celestial%20body, last accessed January 16 2024. Although one might think of larger natural bodies in space such as a planet or moon when contemplating ‘celestial bodies, the aforementioned description reflects that also this term is quite broad.
The ambiguity in terminology showcases the challenges inherent in legal analysis when confronted with unclear wording. The practical consequences of a narrower interpretation could, at least in theory, be that appropriation of whatever does not constitute a celestial body could be permissible. If such an object were to be an asteroid containing valuable resources, the incentive for such an interpretation could be substantial.
In the evolving field of space law, legal scholars have naturally provided their insights on the term ‘celestial body’, adding to the array of interpretations within the field. Ram Jakhu defines it as any natural body outside Earth's atmosphere, encompassing meteorites, planets, asteroids, etc., thus falling under the framework of existing space law.(2) Jakhu (2017), 117-118. This view aligns with the one of ICJ-judge and space law pioneer Manfred Lachs, who posited shortly after the OST's creation that an object's size does not determine its legal classification framework.(3) The views of Lachs was presented in The Law of Outer Space: An Experience in Contemporary Law-Making. Leiden: Martinus Nijhoff Publishers, 2010, originally published 1972, 44. Lyall and Larsen notes that asteroids and comets clearly must be encompassed within this term.(4) Lyall and Larsen (2018), 182. Hobe differentiates between a celestial body as a ‘naturally occurring entity’ and a space object as something artificial, such as a satellite.(5) Hobe (2009), 32.
Despite the lack of a universally accepted definition, the meaning provided by general interpretation and legal scholars suggests that ‘celestial bodies’ includes any natural space object, laying the groundwork for further analysis. This perspective is substantiated by the deliberate omission of a comprehensive list defining its jurisdiction, as evidenced by the phrasing of Article II: "Outer space, including the moon and other celestial bodies [...]" This lack of specificity in the treaty underscores the apparent acceptance of a wide range of objects under the umbrella of ‘celestial bodies’, encouraging a more inclusive approach to the term's legal interpretation.