Efforts in the United Nations to maintain outer space for peaceful purposes began in 1957, months prior to the launch of the first artificial satellite into Earth’s orbit.
Existing Legal Framework
The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (“Outer Space Treaty”) entered into force in 1967, after consideration by the Committee on the Peaceful Uses of Outer Space and the General Assembly. The Treaty provides the basic framework for international space law.
In particular, it prohibits the placement of nuclear weapons or any other kinds of weapons of mass destruction in outer space and the stationing of such weapons on celestial bodies. The establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military maneuvers on celestial bodies are also forbidden. It also establishes basic principles related to the peaceful use of outer space. This includes that the exploration and use of outer space shall be carried out for the benefit and in the interests of all countries and that the moon and other celestial bodies shall be used exclusively for peaceful purposes and not be subject to national appropriation or claims of sovereignty. It also establishes that States Parties shall conduct all their activities in outer space with due regard to the corresponding interests of all other States Parties.
The Outer Space Treaty is one of several international treaties on outer space which were negotiated at the United Nations. Other United Nations treaties on outer space include:
- The 1968 Agreement on the Rescue of Astronauts, the Return of Astronauts and the Return of Objects Launched into Outer Space (Rescue Agreement)
- The 1972 Convention on International Liability for Damage Caused by Space Objects (Liability Convention)
- The 1976 Convention on Registration of Objects Launched into Outer Space (Registration Convention)
- The 1984 Agreement Governing the Activities of States on the Moon and Other Celestial Bodies (Moon Agreement)
In addition, some treaties in the field of disarmament include provisions relating to outer space, including:
- The 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water (Partial Test Ban Treaty)
- The 1976 Convention on the Prohibition of Military or Any Other Hostile Use of Environment Modification Techniques (ENMOD Convention)
Prevention of an arms race in outer space
In paragraph 80 of the Final Document of the first Special Session of the General Assembly devoted to disarmament in 1978, it was agreed that further measures should be taken and appropriate international negotiations held in accordance with the spirit of the Outer Space Treaty, in order to prevent an arms race in outer space.
Efforts within the Conference on Disarmament
Subsequently, the Conference on Disarmament has considered various proposals under the agenda item “prevention of an arms race in outer space” since the early 1980s. The Conference first established an Ad Hoc Committee on the Prevention of an Arms Race in Outer Space in 1985, which reconvened regularly until 1995. The Conference also established subsidiary bodies to discuss the prevention of an arms race in outer space in 2018, 2022, 2024 and 2025.
Efforts within the General Assembly
Since 1981, the General Assembly has annually adopted resolutions on the prevention of an arms race in outer space. The first resolutions on this matter respectively sought an effective and verifiable agreement to prohibit anti-satellite systems (36/97 C) and a treaty on the prohibition of the stationing of weapons of any kind in outer space (36/99).
In 2018 and 2019, the Group of Governmental Experts (GGE) on further practical measures for the prevention of an arms race in outer space convened in accordance with resolution 72/250. Its mandate was to consider and make recommendations on substantial elements of an international legally binding instrument on the prevention of an arms race in outer space, including, inter alia, on the prevention of the placement of weapons in outer space. While the GGE held some of the most in-depth discussions on the matter in more than a decade, it was ultimately unable to reach consensus on a substantive report. The procedural report of the GGE, which includes a report by the Chair of the Group on the work of its first session, can be found in document A/74/77. Information on the work of the GGE can be found here.
In 2022 and 2023, in accordance with resolution 76/231, the General Assembly convened the Open-ended working group (OEWG) on reducing space threats through norms, rules and principles of responsible behaviours. The OEWG’s mandate was to take stock of existing legal and normative frameworks concerning space threats arising from State behaviours, to consider threats by States to space systems, and to make recommendations on possible norms, rules and principles of responsible behaviours relating to outer space threats by States. However, the OEWG was unable to reach consensus on a substantive report nor a procedural report. Nevertheless, the Chairperson prepared a summary of the discussions under his own authority, which can be found here.
In 2023 and 2024, by resolution 77/250, the General Assembly established a new GGE on further practical measures for the prevention of an arms race in outer space. This GGE successfully reached consensus on a final substantive report, which included a non-exhaustive set of possible substantial elements that could be taken into account in further measures and appropriate international negotiations, including in a legally binding instrument on the prevention of an arms race in outer space. The report can be found here.
In 2023, the General Assembly adopted two resolutions, 78/20 and 78/238, which would have established two new OEWGs, one addressing norms, rules and principles of responsible behaviours and the other addressing further practical measures for the prevention of an arms race in outer space. In 2024, by decision 79/512, the General Assembly replaced both OEWGs with a single Open-ended Working Group on the prevention of an arms race in all its aspects. This new OEWG is mandated to convene for the period 2025–2028 and submit recommendations on the prevention of an arms race in outer space in all its aspects. Information on the work of the Group can be found here.
Transparency and Confidence-Building Measures
In 1990, the General Assembly requested the Secretary-General to carry out, with the assistance of a group of governmental experts, a study on the specific aspects related to the application of different confidence-building measures in outer space. This group carried out a study on the specific aspects related to the application of different measures, including different technologies available, and possibilities for defining appropriate mechanisms of international cooperation in specific areas of interest. That group submitted its report in 1993 (A/48/305).
The General Assembly resumed its exploration of transparency and confidence-building measures (TCBMs) in outer space activities in 2005, beginning with resolution 60/66. By resolution 65/68, the General Assembly established a GGE, which met in 2012 and 2013, to conduct a study on the matter. The GGE agreed on a consensus report (A/68/189*), including a set of TCBMs for implementation by States and international organizations on a voluntary basis. Those measures included: information exchange on space policies; information exchange and notifications related to outer space activities; risk reduction notifications; contact and visits to space launch sites and facilities; international cooperation; consultative mechanisms; outreach; and coordination. The GGE also endorsed efforts to pursue political commitments, for example, in the form of unilateral declarations, bilateral commitments or a multilateral code of conduct, to encourage responsible actions in, and the peaceful use of, outer space.
Implementation of transparency and confidence-building measures
The General Assembly has taken a number of steps to advance the implementation of outer space TCBMs. In resolution 68/50 and subsequent resolutions, the General Assembly encouraged Member States to review and implement, to the greatest extent practicable, the proposed TCBMs, through relevant national mechanisms, on a voluntary basis and in a manner consistent with the national interests of Member States. Pursuant to the recommendation of the GGE, the First and Fourth Committees of the General Assembly have held joint ad hoc meetings on a biennial basis, which have addressed possible challenges to space security and sustainability.
Since resolution 69/38, the General Assembly has encouraged the relevant entities and organizations of the United Nations system to coordinate, as appropriate, on matters related to the recommendations contained in the GGE report. In 2015, the Inter-Agency Meeting on Outer Space Activities (UN-Space), coordinated by the Office for Outer Space Affairs, issued a special report on the role of United Nations entities in supporting implementation of the GGE report (A/AC.105/1116).
By resolution 70/53, the General Assembly requested the Secretary-General to submit a report on the coordination of TCBMs in outer space activities in the United Nations system, with an annex containing submissions from Member States on their views on TCBMs in outer space activities. The report (A/72/65) reproduces the substantive text of the special report by UN-Space and incorporates updates received from the contributing entities. The replies received from Governments and one intergovernmental organization can be found in sections IV and V of the report.
United Nations Disarmament Commission
In 2018, the United Nations Disarmament Commission adopted the following item for consideration during its 2018-2020 cycle: In accordance with the recommendations contained in the report of the Group of Governmental Experts on Transparency and Confidence-building Measures in Outer Space Activities (A/68/189), preparation of recommendations to promote the practical implementation of transparency and confidence-building measures in outer space activities with the goal of preventing an arms race in outer space. Information on the 2018 session of the Disarmament Commission can be found here.
National Proposals and Initiatives
Prevention of the placement of weapons in outer space
In 2008, China and the Russian Federation introduced the draft text of a Treaty on Prevention of the Placement of Weapons in Outer Space and of the Threat or Use of Force against Outer Space Objects (PPWT) to the Conference on Disarmament. They introduced a revised draft PPWT in 2014.
No first placement of weapons in outer space
Since 2014, the General Assembly has adopted annual resolutions, at the initiative of the Russian Federation, beginning with resolution 69/32, in which Member States commit not to be the first to place weapons in outer space.
Norms, rules and principles of responsible behaviours
In 2020, the General Assembly adopted resolution 75/36, at the initiative of the United Kingdom, on reducing space threats through norms, rules and principles of responsible behaviours.
Destructive direct-ascent anti-satellite missile testing
In 2022, the General Assembly adopted resolution 77/41, introduced by the United States. That resolution calls upon States to commit not to conduct destructive direct-ascent anti-satellite missile testing.
Weapons of mass destruction in outer space
In 2024, the General Assembly adopted resolution 79/18, introduced by Argentina, Japan, and the United States. The resolution recalled the obligations of States to various treaties and it urged States, taking into account Article IV of the Outer Space Treaty, not to develop nuclear weapons or any other kinds of weapons of mass destruction specifically designed to be placed in orbit around the Earth, to be installed on celestial bodies, or to be stationed in outer space in any other manner.
Role of the United Nations
United Nations Office for Disarmament Affairs
The United Nations Office for Disarmament Affairs (UNODA) provides substantive and organizational support for norm-setting in the area of disarmament through the work of the General Assembly and its First Committee, the Disarmament Commission, the Conference on Disarmament and other bodies. It fosters disarmament measures through dialogue, transparency and confidence-building on military matters, and encourages regional disarmament efforts; these include the United Nations Register of Conventional Arms and regional forums. For outer space in particular, UNODA serves as the secretariat for various bodies and forums relevant to the prevention of an arms race in outer space. These include the Conference on Disarmament which has an agenda item on the prevention of an arms race in outer space, and the various OEWGs and GGEs on outer space security.
United Nations Office for Outer Space Affairs
The United Nations Office for Outer Space Affairs (UNOOSA) serves as the secretariat of the Committee for the Peaceful Uses of Outer Space (COPUOS). The General Assembly established COPUOS in 1959 to govern the exploration and the use of outer space for the benefit of all humanity. In 2010, the Scientific and Technical Subcommittee of COPUOS began considering the long-term sustainability of outer space. In 2019, COPUOS adopted Guidelines for the Long-term Sustainability of Outer Space Activities of the Committee on the Peaceful Uses of Outer Space (A/74/20, para 163 and Annex II) and it also established a Working Group on the Long-Term Sustainability of Outer Space Activities under a five-year workplan. In accordance with its terms of reference, the Working Group was tasked with producing a report on the long-term sustainability of outer space activities, which would contain inter alia experiences and practices from voluntary implementation of the Guidelines, recommendations on possible new guidelines, and information and recommendations for capacity-building activities. COPUOS adopted the report of the Working Group (A/AC.105/C.1/133) in 2026, and agreed to extend the mandate of the Working Group which would draft a new workplan.