Analysis of international treaties and policies related to space nuclear power and propulsion

The accidental re-entry of the Soviet Kosmos 954 satellite, which dispersed radioactive debris over northern Canada, impressed upon the spacefaring world the international nature of the operation of space nuclear systems in space: the launch and use of radionuclides can pose a safety and security threat that transcends national borders. Space nuclear activities fall under the jurisdiction of five international space treaties and are guided by nonbinding resolutions. As interest in space nuclear systems grows, especially among new State and commercial actors, it is important that this corpus of international policy is reviewed to ensure that it is well understood, and sufficiently guides nuclear activities. The research presented in this paper reviews these international treaties and resolutions, along with the secondary literature, to determine their relevance for space nuclear systems. We find that international law covers liability in the event of an accident, but may not sufficiently deter or limit accidents, especially in light of new technologies and the expansion of access to space. The nonbinding principles of Resolution 47/68 give guidance for safe operation, but could be controversial-especially regarding the use of high or low enriched uranium. This research explores these controversies and suggests a path forward that will enable the safe and secure use of space nuclear systems from an international perspective.