Regulating Space-Based Solar Power: Challenges Under Both Space Law and Energy Law

Space-based solar power (SBSP) is emerging as a potential catalyst for global decarbonisation, driven by advances in wireless power transmission, in-orbit assembly, and photovoltaic technologies. Programmes such as the European Space Agency’s SOLARIS initiative, China’s planned megawatt-scale demonstrator, and private projects including Constant Aperture Solid State Integrated Orbital Phased Array and Caltech’s Space Solar Power Project illustrate the shift from theoretical models to operationalisation. SBSP offers continuous, weather-independent renewable energy capable of complementing terrestrial solar, wind, and hydro generation, enhancing grid stability, energy security, and progress toward the UN Sustainable Development Goals. It also supports future space activities by providing scalable power for satellites, lunar infrastructures, and deep-space missions. However, major challenges remain, including radiation-induced degradation, orbital congestion, transmission safety, environmental impacts of large rectennas, and the need for robust beam-control and debris-mitigation strategies. These technical developments intersect with an evolving regulatory landscape shaped by both energy law and space law. Indeed, SBSP raises fundamental questions regarding the legal status of space-generated electricity, the role of states, space agencies, and private actors as energy producers, and how orbital energy should be integrated into national and transnational energy markets. Under the 1967 Outer Space Treaty and related instruments, states retain responsibility for national activities and must avoid harmful interference in outer space. In addition, the launching state would potentially bear international liability for damage caused by SBSP systems. At the same time, terrestrial energy regulators must address licensing, safety, environmental assessment, grid compatibility, and pricing mechanisms for extraterrestrial electricity. This Article argues that effective SBSP deployment requires harmonised governance bridging both space and energy frameworks. A dedicated international agreement or consensus-driven instrument could provide greater legal certainty, promote sustainability, and support the responsible development of SBSP as a strategic renewable energy source.