The IISL’s 15th Nandasiri Jasentuliyana Keynote Lecture on Space Law (2023) highlights a key mission of the IISL: the expansion of the ‘rule of law’ in the exploration and use of outer space for peaceful purposes. The keynote lecture explores the role that the rule of law plays under national and international space law, with the five authors of the keynote lecture each representing a region of the IISL Manfred Lachs Space Law Moot Court Competition: Africa, Asia Pacific, Europe, Latin America, and North America. We highlight regional understandings and historical developments of the rule of law in outer space, and explore the manner in which rule of law leads to the development of space law. We advocate a ‘functional’ understanding of rule of law that bridges the traditional divide between legally and non-legally binding instruments of space law.