A NASA-led study indicates that light reflections from the increasing number of orbiting satellites could affect over 95% of images captured by some space telescopes within the next decade. These reflections manifest as streaks, termed satellite trails, and have already been observed in images from NASA's Hubble Space Telescope. Researchers state that this issue is intensifying as more satellites are deployed into Earth's orbit.
Impact on Space Telescopes
The study, published in Nature, forecasts that several future telescopes, including NASA's SPHEREx (launched this year), the European Space Agency's ARRAKIHS, and China's Xuntian Space Telescope (both awaiting launch), could produce streak-affected images. Alejandro S. Borlaff, the study's lead author and a NASA scientist, highlighted that critical astronomical data, such as observations of distant exploding stars, could be permanently lost if a satellite trail interferes with an image.
Satellite Proliferation
Borlaff reported that the number of satellites launched in the last four years exceeds those launched in the previous 70 years combined. As of December 1, over 10,000 active satellites are in orbit, with SpaceX operating more than 7,800 Starlink satellites, according to data compiled by astrophysicist Jonathan McDowell. The International Telecommunication Union (ITU) has noted plans for thousands more satellites to be launched.
Projected Contamination Levels
A separate study from 2023, published in Nature Astronomy, indicated that between 2018 and 2021, approximately 4% of Hubble Space Telescope images showed light streaks from satellites. Borlaff's study projects this figure could increase, with at least one in every three Hubble images potentially displaying a light streak. For SPHEREx, ARRAKIHS, and Xuntian telescopes, the study anticipates that approximately 96% of images could experience contamination. The research also suggests potential impacts on ground-based telescope observations.
Community Response and Mitigation
The astronomical community has consistently expressed concerns regarding satellite trails. The American Astronomical Society (AAS) has previously warned about the potential for increased satellites in low Earth orbit to cause collisions and create light streaks and glares in telescopic images. Roohi Dalal, AAS Deputy Director of Public Policy, stated that the society would continue collaborative efforts with federal agencies and the satellite industry to understand and minimize these effects. SpaceX has previously outlined steps to reduce light reflections from its satellites, including testing darker coatings, integrating sun-blocking visors, and adjusting orbital parameters to minimize reflected sunlight.
Regulatory Concerns
The ITU has also voiced concerns about the rapid increase in satellites, noting in a recent report that it "poses significant risks to space sustainability, including collisions and debris generation, threatening the long-term viability of orbital resources." The agency has advocated for stricter international regulations and improved management of satellite networks.