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United Nations Agrees to Address Impact of Satellite Constellations on Astronomy

Feb. 15, 2024
After several years’ work by astronomers affiliated with the IAU CPS, a key UN body agreed last week to put on their agenda the issue of satellite constellations' impact on astronomy.

After intense discussions, the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) Scientific and Technical Subcommittee has agreed to include an item on its provisional agenda for the next five years with the title “Dark and Quiet Skies, astronomy and large constellations: addressing emerging issues and challenges”. As the UN’s top body for space-related matters, with delegates from more than 102 countries, COPUOS deals with all topics related to international cooperation and the exploration of space and planetary bodies, including the deployment of satellites, space debris mitigation, the long-term sustainability of space and the use of orbital slots.

The proposal, championed by Chile and Spain — both countries hosting significant international astronomy infrastructure — and the astronomy community, received widespread support and was co-signed by several delegations [1]. The International Astronomical Union (IAU), European Southern Observatory (ESO), European Astronomical Society (EAS), and Square Kilometre Array Observatory (SKAO), all permanent observers in the committee, encouraged and supported the efforts.

“This is a significant diplomatic moment for astronomy,” said Richard Green, Interim Director of the IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (CPS). “Since the first constellation launches in 2019, we have been working hard to raise awareness of this issue with all relevant parties and at all levels. It’s very gratifying to see the United Nations recognise its importance and agree to look into the issues and challenges posed by large constellations.”

The draft provisional agenda will now go before the full committee in June to be endorsed. As a dedicated agenda item, there will be more time for in-depth discussions between delegations, the ultimate goal being to develop and agree on recommendations to be adopted by Member States.

This recent success reflects a growing recognition of the importance of preserving dark and quiet skies for both astronomical research and humanity’s cultural heritage. Support for these initiatives has been steadily growing in COPUOS over the past couple of years. In October, at an IAU expert meeting on satellite constellations, the delegations from Spain and Chile launched a Group of Friends of the Dark and Quiet Sky for Science and Society, for which the CPS provides the technical secretariat. The group already includes 16 delegations and 6 permanent observers and was recognised as a valuable forum in which to discuss the issue until the next session of the committee.

“Chile places great importance on protecting international public investments in astronomy infrastructure, many of which we host in Chile,” explained Mila Francisco, Chilean diplomat and a representative to the UN Office in Vienna. “It’s been very valuable engaging with astronomers to understand their concerns and discussing these with other delegations in a spirit of compromise to agree a way forward.”

Following four years of thorough work by astronomers to quantify and communicate the impact of satellite constellations on existing and upcoming astronomy facilities, the number of diplomats and policy-makers recognising the issue and taking action has grown in recent months. In May 2023 Science and Technology Ministers from the G7 emphasised the importance of continued discussion of this issue in international forums. In December 2023 delegations from 193 countries represented at the International Telecommunications Union (ITU) — the UN’s specialised agency for information and communication technologies — agreed to study potential new protections from satellites for radio astronomy over the next four years.

“The last time there was an agenda item on radio astronomy in the ITU was over a decade ago, so this really shows the significant profile and attention that astronomy has garnered in international bodies like the UN,” said Federico di Vruno, co-director of the CPS based at the SKAO.

While efforts in international forums like the UN and ITU continue, countries are also starting to implement legislation to better protect astronomy. In the US, the Federal Communications Commission has started requiring satellite operators to work with the National Science Foundation to mitigate their impact.

“The CPS welcomes the introduction of such measures from national regulators and encourages other national jurisdictions to adopt similar steps,” added Connie Walker, co-director of the CPS based at NSF’s NOIRLab. 

At the same time, industry continues to engage proactively with the astronomy community, developing and testing new mitigation measures that astronomers then evaluate. A dozen satellite operators are already engaging regularly within the IAU CPS.

The IAU CPS looks forward to supporting the work of the Group of Friends in developing positions for COPUOS, and will continue to engage with all stakeholders to develop practical mitigation measures, and propose regulation where necessary that both supports technological development while safeguarding the science of astronomy.


[1] Argentina, Austria, Belgium, Bulgaria, Chile, Colombia, Czechia, Denmark, Ecuador, Germany, Italy, the Netherlands (Kingdom of), Paraguay, Peru, Slovakia, South Africa, Spain, Switzerland.

More information

The IAU is the international astronomical organisation that brings together more than 12,000 active professional astronomers from more than 100 countries worldwide. Its mission is to promote and safeguard astronomy in all its aspects, including research, communication, education and development, through international cooperation. The IAU also serves as the internationally recognised authority for assigning designations to celestial bodies and the surface features on them. Founded in 1919, the IAU is the world's largest professional body for astronomers.

The International Astronomical Union’s Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (IAU CPS) is a global organisation co-hosted by the US-based NSF’s NOIRLab and the SKA Observatory (SKAO), under the auspices of the IAU. The CPS facilitates global coordination of efforts by the astronomical community in concert with observatories, space agencies, industry, regulators and other sectors to help mitigate the negative consequences of satellite constellations on astronomy.

NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.

The SKAO, formally known as the SKA Observatory, is an intergovernmental organisation composed of Member States from five continents and headquartered in the UK. Its mission is to build and operate cutting-edge radio telescopes to transform our understanding of the Universe, and deliver benefits to society through global collaboration and innovation.

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. ESO designs, builds and operates world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promotes international collaboration for astronomy. An intergovernmental organisation supported by 16 Member States and two partner countries, ESO has headquarters in Germany and operates three observing sites in Chile.

The European Astronomical Society (EAS) is an international organisation founded in 1990, counting over 5000 members in Europe and beyond. Aimed at promoting and advancing astronomy in Europe, the EAS acts on matters that need to be handled at a European level on behalf of the European astronomical community. In its endeavours the EAS collaborates with affiliated national astronomical societies and also with pan-european research organisations and networks.


Richard Green
Interim Director
IAU Centre for the Protection of the Dark and Quiet Sky From Satellite Constellation Interference
Email: rgreen@lbto.org

Federico Di Vruno
IAU Centre for the Protection of the Dark and Quiet Sky From Satellite Constellation Interference
SKA Observatory
Phone: +44 7384 511248
Email: federico.divruno@skao.int

Connie Walker
IAU Centre for the Protection of the Dark and Quiet Sky From Satellite Constellation
Email: connie.walker@noirlab.edu

Mathieu Isidro
Communications and Outreach Lead
IAU Centre for the Protection of the Dark and Quiet Sky From Satellite Constellation Interference
Email: mathieu.isidro@cps.iau.org / mathieu.isidro@skao.int

Lars Lindberg Christensen
IAU Director of Communications/NOIRLab Head of Communications, Education & Engagement
Cell: +1 520 461 0433/+49 173 38 72 621
Email: lars.christensen@noirlab.edu

Josie Fenske
NSF's NOIRLab Communications
Email: josie.fenske@noirlab.edu


The United Nations Office in Vienna, Austria
The United Nations Office in Vienna, Austria which houses the United Nations Office for Outer Space Affairs and the meetings of the UN Committee on the Peaceful Uses of Outer Space (UN COPUOS). See more


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