Long-Term Sustainability Guidelines

The Long-Term Sustainability (LTS) Guidelines for Outer Space Activities are a voluntary, non-binding framework adopted by the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) in June 2019. They emerged from nearly a decade of negotiations within a dedicated Working Group established in 2010 under the COPUOS Scientific and Technical Subcommittee. The final package contains 21 guidelines, organized around four thematic areas:

• Policy and regulatory framework for space activities at the national level
• Safety of space operations, including conjunction assessment and pre-launch notifications
• International cooperation, capacity-building and awareness
• Scientific and technical research and development

The guidelines respond to growing pressures on the orbital environment, including the proliferation of small satellites, mega-constellations, space debris, and the increasing number of state and non-state actors conducting space activities. They encourage states to enact national space legislation, share orbital data, register space objects in accordance with the 1975 Registration Convention, and design satellites for end-of-mission disposal.

Although voluntary, the LTS Guidelines build on and complement the binding outer space treaty regime, particularly the 1967 Outer Space Treaty and the 1972 Liability Convention. They also reinforce the 2007 UN Space Debris Mitigation Guidelines.

Implementation has been uneven. In 2021, COPUOS established a new Working Group on the Long-term Sustainability of Outer Space Activities under a five-year mandate to assist states with implementation, identify new challenges, and consider additional guidelines. Delegates in Model UN simulations of COPUOS or the First Committee (Disarmament and International Security) frequently invoke the LTS Guidelines when debating space traffic management, debris remediation, and the conduct of rendezvous and proximity operations. The guidelines are notable as one of the few areas of broad consensus in contemporary space governance, where binding rule-making has largely stalled.