Drawing lines in a borderless outer space: legal challenges to the establishment of safety zones

Abstract

International outer space law, primarily developed in the late 1960s and 1970s, increasingly reveals its limitations in addressing the complexity and scale of contemporary space activities. As of 31 December 2024, approximately 18,070 functional space objects had been officially registered —representing nearly 89% of all launches since 1957— underscoring the intensity and acceleration of orbital operations. Concurrently, multiple missions targeting lunar exploration and utilization are actively underway. This rapid evolution has exposed significant normative gaps, particularly concerning the legal status and operationalization of safety zones. Such zones are gaining relevance as instruments to mitigate orbital congestion, prevent harmful interference, safeguard critical infrastructure and ensure the safe execution of high-risk operations, including the exploitation of celestial resources. Notably, safety zones have not been established through binding multilateral instruments, but have instead emerged from the operational practices of spacefaring actors, as well as from policy measures articulated in soft law instruments. Considering this, the main research question addressed is: To what extent are the establishment and enforcement of safety zones lawful under the current corpus of international space law? The study seeks to highlight the urgent need for coherent, equitable, and enforceable international rules capable of addressing these emerging regulatory challenges.