A key aspect of space sustainability is the cleaning up, removing, monitoring, tagging and classifying of space debris, which has major implications in the safety and operationalization of space use and exploration, but also brings about new commercial opportunities for the space sector.

Preventing orbital congestion and the proliferation of space debris are among the biggest global challenges faced in the space sector today. Thus, it is without surprise that the G7 Leaders have committed to act in order to assure a safe and sustainable use of the outer space particularly by tackling the growing hazard of space debris through the creation of common rules.

Still, as of now, States and national space authorities refer to (and private stakeholders are bound to) guidelines, best practices and principles that are set under international legal instruments such as the COPUOS Space Debris Mitigation Guidelines (in particular, Guideline 6), IADC’s Space Debris Mitigation Guidelines, the Outer Space Treaty and the Liability Convention, as well as standards set out in ISO 24113:2011 (Space systems – Space debris mitigation requirements). We note also, in this respect, the launch, in June 2022, of the Space Sustainability Rating (SSR). Hosted by the eSpace-EPFL Space Center, the SSR serves as a tool to support space actors in more sustainable mission design and operations and is further linked to the assessment of organizations’ debris mitigation efforts.

International rules and guidelines have in many instances been incorporated in national laws – notably when setting out licensing requirements that deal with the need for operators to evidence debris mitigation measures and plans (e.g., Portugal, the UK and France) –, as well as in rules prepared by agencies with responsibility on space matters (e.g. the US FCC Rule on mitigation of debris). In this case, such international rules and guidelines become mandatory obligations for space operators subject to national laws. Yet, beyond reflecting international rules and guidelines in national law, the application of existent environmental law obligations and principles (such as the mandatory undertaking of an environmental impact assessment and/or the application of the precautionary and polluter-pays principles) may also be a relevant aspect to be considered in space activities.

Beyond mitigation, active removal of space debris is becoming increasingly relevant and gives light to new business models and services in the new space sector. For instance, OneWeb and Astroscale announced a new spacecraft technology – ELSA-M – to deliver a debris removal service to satellite operators. ELSA-m satellite demonstrator launch is scheduled for the end of 2024 and is funded, among others, by the UK Space Agency (UKSA) and the European Space Agency (ESA).

On the other hand, ESA’s ADRIOS programme has its ongoing ClearSpace-1 mission planned to launch in 2025-26, which aims to establish a new market for in-orbit servicing and debris removal. A similar programme is also being promoted by the Japanese Space Agency (JAXA), with Rocket Lab set to launch the ADRAS-J satellite in 2023.

Actively removing space debris raises complex legal issues which the current legal regime does not solve and that ought to be carefully considered, e.g., the conceptual scope and legal definition of “space debris”, the challenge of liability allocation for activities conducted in outer space, ownership/intellectual property of space objects, as well as cybersecurity, confidentiality and national security/defence matters that are of particular relevance when the entity promoting the removal of space debris is not the same as the one launching the objects that now qualify as debris.

Moreover, the use of new technologies in space - such as AI, DLT/ blockchain and quantum technology, for instance for automatic collision-avoidance services – also brings new legal challenges that require due attention by space stakeholders.

As such, stakeholders ought to carefully assess the current and future guidelines and obligations aimed at space debris mitigation and removal, as well as the opportunities arising therefrom, and prepare their legal frameworks (in case of States) and internal compliance mechanisms (in case of space operators) taking into consideration such guidelines and obligations.