The Obligation to Conduct Environmental Impact Assessments in the Sustainable Development of Mega-Constellations

Abstract The development of satellite mega-constellations promises substantial benefits but also exacerbates environmental risks, including primarily the proliferation of space debris, interference with astronomy, and effects on the atmosphere. This article explains the critical role of environmental impact assessments (EIAs) in ensuring the sustainable development of mega-constellations and argues that EIAs should be regarded as part of existing international space law. On the one hand, heightened environmental risks from space activities render EIAs increasingly relevant, if not indispensable, for implementing the obligations under Article IX of the Outer Space Treaty. On the other hand, while Article III of the Treaty enables the application of general international law on EIAs to outer space, its scope is constrained to activities that are likely to cause a significant adverse impact. The analysis also addresses the operationalization of EIAs with regard to mega-constellations by identifying the responsible state, assessing the significance of environmental impacts, articulating minimum standards, and developing appropriate mechanisms.