ann21039 — Announcement

Constellation satellites in low Earth orbits
10 June 2021
IAU Launches Call for Proposals for New Centre for the Protection of Dark and Quiet Skies

The International Astronomical Union (IAU) invites proposals for the establishment of an IAU Coordination Centre for the Protection of Dark and Quiet Skies. The centre will foster the development of tools and procedures that can mitigate the impact of satellite constellations on astronomy, and will negotiate directly with the space companies and industries. Interested institutes or organisations are invited, individually or in partnerships, to submit proposals to host the centre.

Under its mission to promote and safeguard astronomy in all its aspects — research, communication, education and development — through international cooperation, the International Astronomical Union (IAU) remains deeply concerned about the increasing number of launched and planned launches of satellites constellations in mainly low-Earth orbits. The IAU embraces the principle of a dark and radio-quiet sky as not only essential to advancing our understanding of the Universe of which we are a part, but also for the cultural heritage of all humanity and for the protection of nocturnal wildlife.

The work protecting the astronomical sky from artificial interference has so far taken place in Commissions and Working Groups such as the Executive Committee Working Group Dark and Quiet Sky Protection and the Inter-Division Commission B7 Protection of existing and potential observatory sites.

The protection of the dark and quiet sky has recently become a particularly acute issue with the advent of large constellations of communication satellites in low Earth orbit (LEO). This new threat adds to those represented by artificial light at night (ALAN) and the interference by transmission at radio wavelengths, which have become increasingly serious as a result of technological advancements.

The overall situation has been thoroughly analysed in the Report of the online Workshop Dark and Quiet Skies for Science and Society (hosted by UNOOSA, IAU and Spain, with support from NSF’s NOIRLab), which contains a number of recommendations for possible mitigation actions.

That Report highlighted that the types of interference caused by satellite constellations are substantially different from other types of interference, because they affect astronomical observations globally rather than locally and therefore require mitigation measures that can be agreed and implemented worldwide.

The Report can be considered a cornerstone of the necessary international actions to protect the skies; an executive summary, in the form of a Conference Room Paper, was presented to the 58th meeting of the Scientific and Technical Sub-Committee (STSC) of the UN Committee on the Peaceful Uses of Outer Space (COPUOS). The STSC agreed on the relevance and urgency of the issue and has encouraged UNOOSA, in collaboration with the IAU, to continue the discussion with all stakeholders and to report its findings to the next STSC meeting in 2022.

The IAU will continue to pursue actions at UN level, aiming to obtain internationally agreed regulations governing the characteristics of large satellite constellations. At the same time, the IAU sees benefit in coordinating a parallel effort aimed at negotiating directly with the space companies and industries, as well as fostering the development of tools and procedures that can mitigate the impact of satellite constellations.

Satellite constellations are creating totally new challenges for observational astronomy. Meeting these challenges calls for not only controlling the source of interference, but also developing innovative observing and data analysis procedures. Tackling this complex problem is well beyond the capability of an IAU Commission or even of a single observatory or institution, particularly given that the impact concerns both the optical and radio domains. The experience gained by the organisation of the Dark and Quiet Skies for Science and Society Workshop shows that an internationally coordinated effort is possible and can produce concrete results in a reasonably short time.

Taking all the above into consideration, the Executive Committee of the IAU, in its 105th Meeting on 22 April 2021, approved the establishment of an International Coordination Centre for the Protection of Dark and Quiet Skies. Using a procedure similar to that used for the constitution of the other IAU Offices (OAD, OAO, OYA, OAE), the location of the centre will be decided via this Call for Proposals. It is expected that the centre will be hosted by an existing institute or organisation of excellence, or a partnership thereof, with proven experience in international cooperation. Interested institutes or organisations are invited, individually or in partnerships, to submit proposals to host the centre.

The mission of the centre can be summarised as follows:

  1. Coordinate the observation and measurement of the optical and radio interference caused by satellite constellations.
  2. Establish contacts with the space companies and industries involved in the construction and deployment of LEO satellites in order to discuss relevant mitigation measures.
  3. Foster and coordinate the study and testing of hardware solutions aimed at reducing reflected sunlight by the satellites and spurious radio emission in the side-lobes of the satellite transmitters.
  4. Interface with space agencies in order to get access to accurate and up-to-date orbital parameters of all LEO satellites.
  5. Coordinate the development of “smart” scheduling and/or detector operation software as well as specific artifact removal algorithms and distribute them.
  6. Provide suggestions for possible international regulations governing LEO satellites to the IAU Officers, in support of their pursuing the matter at COPUOS level.
  7. Maintain regular contact on matters of common interest with the other IAU Offices (OAD, OAO, OYA, OAE).
  8. Create and maintain a dedicated set of web pages under for disseminating information about the protection of dark and quiet skies from satellite interference.
  9. Organise thematic workshops (online and/or in person) as needed.

Proposals should include at least the following elements:

  • Identification of the proposer entity (name, type of organisation, location, country);
  • Statement of interest in hosting the centre;
  • Indication of resources (personnel, infrastructural and financial) to be made available for hosting the centre, and what contribution is expected from the IAU;
  • Executive summary of the main programmatic lines and goals proposed for the centre’s activity for a period of 5 years;
  • Proposed timeline for the establishment of the centre.

The IAU Executive Committee will appoint an evaluation committee that will select the centre’s host. After the selection, the IAU and the selected host will enter into negotiation to draft an MoU to be signed by both parties. The centre will be established for an initial period of five years, renewable upon review. Proposals submitted by a consortium of coordinated entities are encouraged. A prompt timeline for the establishment of the centre is preferred.

Deadlines and evaluation timeline:

  • 10 September 2021, 12:00 pm CEST: Proposals (preferably < 25 000 characters) should be received by Assistant General Secretary José Miguel Rodriguez Espinosa 
  • 1 October 2021: Completion of phase 1 of the evaluation process, short list of candidates identified, negotiation begins.
  • 30 November 2021: MoU between the IAU and the selected host signed. 

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.


Piero Benvenuti

José Miguel Rodriguez Espinosa
Assistant General Secretary

Lars Lindberg Christensen
IAU Press Officer
Cell: +49 173 38 72 621

About the Announcement



Constellation satellites in low Earth orbits