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Satellite Constellations
2025-2026
What are satellite constellations?
Humans have been launching satellites into space for nearly 70 years, for purposes including communications, defense, science, and navigation. The number of satellites in orbit has increased dramatically in the last few years, mostly due to large groups called satellite constellations; the Starlink and OneWeb constellations are two examples. Satellite constellations bring potential for substantial benefits, for example in communications to remote areas and remote monitoring of the Earth, but also for substantial harms, for example in polluting the Earth’s environment through during launch and re-entry or polluting the space environment through reflected sunlight or the production of orbiting space debris. Governments, companies, international scientific organizations, individuals, and future societies are all affected by satellite constellations. Canada’s large land mass at high latitude makes it both particularly vulnerable to harms from satellite constellations and particularly in need of their potential benefits.
What was this project about?
Under the auspices of Western’s Rotman Institute of Philosophy, we brought together experts on environmental philosophy, astronomical observations, space technology, and space law to examine the potential and problems of satellite constellations. We envision satellite constellations as an initial focus in addressing the grand research challenge of “how should access to space be shared?” and intend our findings to be of interest to those who use space (e.g., corporations, space agencies), those who benefit from its use (researchers and various publics), and the policymakers, both domestic and international, responsible for regulation.
What did we find?
Controversies related to satellite constellations can be separated into concerns about orbital debris, light pollution, climate change and socio-economic issues. Satellite constellations contribute to orbital debris and increase the chances of the potentially catastrophic Kessler syndrome in which an unstoppable chain reaction of collisions could make low Earth orbit unusable. Satellites might not be bright enough to disturb normal everyday activities, but they are bright and numerous enough to disrupt the quietness of the skies, our studies of celestial phenomena, and the relationship we have with the stars. Satellite constellations are seen as both a tool useful to study the progression of climate change and a cause of acceleration for it, through atmospheric pollution. Due to control by a few companies and countries, the unregulated development of satellite constellations could negatively contribute to the power imbalances already existing in the world.
We determined that there are numerous gaps in domestic and international law relating to satellite constellations, including lack of binding international regulations and a dispute-settling mechanism, as well as failure to consider the environment. In our large-scale survey of satellites from ground-based observations, we found that most current satellite constellations fail to meet brightness limits set by the International Astronomical Union’s Centre for the Protection of the Dark and Quiet Sky. The impact of satellite reflections is concentrated in the twilight hours at the beginning and end of the night and will thus be particularly damaging to activities such as searches for potentially hazardous asteroids.
Faculty Members:
- PI: Pauline Barmby, Distinguished University Professor, Department of Physics & Astronomy, Faculty of Science
- Sarah Gallagher, Professor, Department of Physics & Astronomy, Faculty of Science
- Eric Desjardins, Associate Professor, Department of Philosophy, Faculty of Arts & Humanities
- Valerie Oosterveld, Professor, Faculty of Law
- Denis Vida, Adjunct Research Professor, Department of Physics & Astronomy, Faculty of Science
Trainees:
- Ghazal Andalib, PhD Student, Faculty of Law
- Sara Varon Echeverri, PhD Student, Department of Philosophy, Faculty of Arts & Humanities
- Jack Johnson, PhD Student, Department of Philosophy, Faculty of Arts & Humanities
Project Summary Report:
Satellite Constellations: Philosophy, Law,and Science
Public Lecture:
"Mega Satellite Constellations", Rotman Insitute Fall Public Lecture Series, November 6, 2026
Op-Ed:
Gallagher, S., Oosterveld, V., & Barmby, P. (2025, October 10). Science and governance: Dual opportunities for Canadian leadership in space. TheFutureEconomy.ca. https://thefutureeconomy.ca/op-eds/science-and-governance-dual-opportunities-for-canadian-leadership-in-space
Pre-Print Journal Article:
Title: "Impacts of Megaconstellation Satellite Brightness on Optical Astronomy: A Large-Scale Optical Survey of Low-Earth Orbit”
Authors: Jack Rayworth1, Denis Vida2,3, Pauline Barmby1,2,3, Peter G. Brown2,3, Sarah Gallagher2,3, Michael J. Mazur2, David L. Clark2,3, Maximilia Vovk2, Stanimir Metchev2, Lauchie Scott4
1 Rotman Institute of Philosophy, The University of Western Ontario, London, Ontario, Canada, 2 Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canad, 3 Institute for Earth and Space Exploration, The University of Western Ontario, London, Ontario, Canada, 4 Defence R&D Canada Ottawa, Ottawa, Ontario, Canada