The night sky’s clarity is under threat like never before, and many wonder: how much longer can we continue our groundbreaking astronomical observations amid the surge of low Earth orbit (LEO) satellites? But here’s where it gets controversial — should satellite operators bear the blame, or is it up to astronomers and policymakers to find a workable solution? This discussion delves into the recent findings from a report that highlights the growing challenge of satellite interference on ground-based optical astronomy, especially for the Rubin LSST (Legacy Survey of Space and Time).
The Vera C. Rubin Observatory (https://rubinobservatory.org/) made its first impressions on the universe earlier this year, and it’s set to revolutionize our understanding of the cosmos over the next decade through the LSST. This vast survey will image the southern sky repeatedly, capturing detailed images every few nights. Its scientific goals are ambitious and wide-ranging: probing dark matter and dark energy, discovering and tracking asteroids and comets, mapping the structure of our Milky Way, and exploring transient phenomena like supernovae and gamma-ray bursts — all objects that often flicker or brighten over short periods. LSST’s extraordinary depth and coverage will shine a light on faint, elusive entities such as low-surface-brightness galaxies and faint tidal streams, which are key to unraveling cosmic evolution.
But—and this is the part most people miss—the very tools that make LSST so powerful are under siege from the increasing number of satellites orbiting our planet. Currently, more than 10,000 LEO satellites clutter the skies, and forecasts estimate this number could balloon to over 100,000 by 2030, which is just midway through LSST’s planned observing period. Satellite streaks—bright, misleading lines across astronomical images—don’t merely obstruct our view; they risk being mistaken for genuine transient phenomena, like supernovae, or distort the data we need to understand the universe’s faint structures.
A recent workshop at UC Davis in August 2025 brought together researchers and satellite industry representatives to address these mounting issues. The consensus? A proactive, collaborative approach is essential to safeguard astronomical science, particularly for low-brightness research that is especially vulnerable to interference. Despite invitations, only one engineer from SpaceX attended, illustrating the challenges in industry-academic cooperation.
Since LSST’s focus is on detecting faint signals, its image processing techniques are tuned to preserve even the tiniest features. Unfortunately, this means minor satellite trails, particularly their dim fringes, are also retained in the images. Over multiple exposures, these faint streaks can mimic real cosmic structures, such as the delicate tidal tails of galaxies or intracluster light — the faint glow permeating galaxy clusters. Losing sight of these features would severely hinder our understanding of galactic formation and evolution, underscoring the urgent need for better strategies.
To better protect the science, the report suggests that satellite builders consider the entire lifecycle of their satellites when it comes to brightness regulations. Many proposals currently focus only on operational altitude, ignoring the weeks or months satellites spend in transitional lower orbits, or the bright streaks resulting from deorbiting and atmospheric re-entry — phenomena that can introduce even more complex imaging artifacts.
Interestingly, the report advocates for placing satellites at lower altitudes despite their increased brightness because these faster-moving objects produce narrower streaks in images, reducing their overall impact on LSST data. For example, lowering the current altitude of the Starlink V2 constellation from 550 km to 350 km could reduce the number of bright satellites crossing LSST’s field of view by about 40%. Although lower-altitude satellites are more affected by atmospheric drag, which shortens their operational lifespan, the trade-off benefits the quality of astronomical data by making the satellites’ light more defocused and less disruptive.
Another key recommendation is to enforce that satellites be kept fainter than magnitude 7 in the V-band. This threshold aligns with levels at which certain image artifacts, like ghost images caused by crosstalk, can be more readily corrected during data processing. The authors also warn vehemently against the deployment of extremely bright satellites—such as those planned by some companies to reflect sunlight onto Earth intentionally—as these would be catastrophic for astronomy.
Transparency in satellite operations is critical, too. Making satellite trajectories publicly available allows LSST’s scheduling algorithms to avoid areas with high satellite traffic, minimizing their impact. However, this requires precise and reliable data from satellite providers, emphasizing a need for industry and space agencies to collaborate openly.
Finally, the report emphasizes that astronomers should actively participate in developing algorithms to identify and remove satellite artifacts from images effectively. Since current detection methods often miss faint streaks, these artifacts can be mistakenly cataloged as real celestial objects, leading to erroneous scientific conclusions. Moreover, continued international collaboration is vital for establishing regulations on satellite deployment and managing space debris, ensuring that our night sky remains accessible for scientific discovery rather than becoming an overcrowded corridor.
In conclusion, as satellite proliferation accelerates, the question remains: can we strike a balance that preserves the integrity of ground-based astronomy without hindering the growth of space-based technology? Or are we destined to watch our view of the universe fade behind a growing constellation of artificial lights? Join the conversation — do you believe more regulation is the answer, or should astronomers adapt to this new reality? Let us know your thoughts below.