Outer space, once conceived as the ultimate symbol of collective human curiosity, has evolved into a contested arena of commercial ambition, technological dominance, and geopolitical competition. The legal architecture that governs this domain, The Outer Space Treaty (1967) and its companion instruments was drafted in an era that could not anticipate the twenty-first century’s exponential rise in private actors, dual-use technologies, and market-driven exploitation. The growing militarisation of orbit, unregulated satellite constellations, and commercial resource extraction have exposed the inadequacies of the existing treaty framework and the fragmentation of national regulatory regimes.

This paper develops the normative case that outer space represents "humanity's second commons, necessitating a global regulatory authority, GRA, analogous yet different from structures like the IMO and ITU. It first places the theoretical underpinning of a "second commons" within classical theories of global commons and cosmopolitan justice, underpinned by Grotius's mare liberum, Ostrom's collective governance model, and Rawlsian fairness. Subsequently, it addresses institutional and legal insufficiencies of the existing regime, evaluating the gap existing between aspirational non-appropriation and practical assertions of sovereignty. It concludes by proposing an institutional model for a GSA with legislative, monitoring, and adjudicatory functions undergirded by inclusive multilateralism and technological equity.