A growing constellation of satellites in low Earth orbit threatens to render ground-based telescopes obsolete, according to experts. If the number of active satellites surpasses 100,000, reflected sunlight and radio interference could overwhelm observations of the universe from the planet's surface. Some companies are proposing constellations that would put millions of spacecraft into orbit, dramatically accelerating this risk.
Satellite streaks already contaminate a significant fraction of images from wide-field surveys like those taken by the Vera C. Rubin Observatory. Reflective surfaces and bright transmissions create trails that obscure faint astronomical signals. The cumulative effect grows worse as the total number of satellites increases, with no current regulatory limit on brightness or density.
No specific timeline for reaching 100,000 satellites has been established, but proposed mega-constellations from firms such as SpaceX's Starlink and others could push the count well into the hundreds of thousands within the next decade. The Federal Communications Commission has approved tens of thousands of satellites already, with many more applications pending.
The impact would be catastrophic for fields reliant on optical and radio observations, including exoplanet research, dark energy studies, and asteroid detection. Astronomers argue that without coordinated international action on brightness standards and orbital cap limits, the loss of ground-based astronomy is a plausible near-term outcome.
Counter-argument: Satellite operators note that technological mitigations, such as darkening coatings, visors, and precision pointing, can reduce brightness, and that space-based telescopes like Hubble and Webb will remain unaffected. However, ground-based observatories provide far more observing time and are essential for survey science that complements space telescopes.