Satellite Swarms Threaten to Blind Space Telescopes, New Study Warns
A growing constellation of satellites orbiting Earth poses an unprecedented threat to astronomical observation, with a new study revealing that reflections could contaminate over 95% of images captured by some space telescopes within the next decade.
The increasing prevalence of satellite trails – streaks of light caused by reflected sunlight – is already impacting images from observatories like the Hubble Space Telescope, and the problem is poised to escalate dramatically as more satellites are launched. Researchers warn that upcoming missions, including NASA’s SPHEREx, the European Space Agency’s ARRAKIHS, and China’s Xuntian Space Telescope, are particularly vulnerable.
“A prized image could come when you are observing a galaxy and then suddenly a star far, far away explodes,” explained a NASA scientist and lead author of the study, published Wednesday in Nature. “But if you happen to have a satellite crossing, you will lose that information forever.”
The surge in satellite numbers is staggering. According to data from astrophysicist Jonathan McDowell at the Harvard-Smithsonian Center for Astrophysics, more than 10,000 active satellites are currently in orbit as of December 1st – a figure exceeding the total launched in the previous 70 years combined. The vast majority of these belong to SpaceX, with over 7,800 Starlink satellites currently operational. The International Telecommunication Union (ITU) anticipates “thousands more” launches in the near future.
Between 2018 and 2021, approximately 4% of images from the Hubble Space Telescope were affected by satellite light streaks, according to a 2023 study in Nature Astronomy. However, researchers now predict that this number could climb to one in every three images for Hubble, and a staggering 96% contamination rate for newer telescopes like SPHEREx, ARRAKIHS, and Xuntian.
“That’s a staggering number. That’s really really high compared to what we see right now,” the NASA scientist stated in a related podcast interview. The impact isn’t limited to space-based telescopes; ground-based observatories are also at risk.
The American Astronomical Society (AAS) has long voiced concerns about the potential for collisions with space telescopes and the interference caused by satellite glares and streaks. “We will continue to facilitate collaborative work with federal agencies and the satellite industry to fully understand and minimize the impacts of large satellite constellations on astronomy,” said Roohi Dalal, AAS Deputy Director of Public Policy, in a statement on Sunday.
SpaceX has previously acknowledged the issue and indicated it is taking steps to mitigate the problem, including testing darker coatings, adding visors to block sunlight, and adjusting satellite orbits to reduce reflectivity. However, a request for comment from SpaceX regarding the new study went unanswered.
The ITU has also raised alarms about the sustainability of space, noting that the rapid increase in satellites poses risks of collisions and the creation of orbital debris, jeopardizing the long-term viability of space resources. The agency is advocating for stricter international regulations governing the number of satellites and improved network management.
The future of astronomical observation hinges on finding a balance between the benefits of increased satellite connectivity and the preservation of our ability to explore the universe. Without concerted action, the night sky – and the invaluable data it holds – could be irrevocably compromised.
