1.7 million satellites could end astronomy as we know it and SpaceX is leading the charge

There are currently more than 14,000 satellites orbiting the Earth. That number, already unprecedented in the history of spaceflight, is set to grow by a factor of more than a hundred. Companies have proposed launching an additional 1.7 million satellites into low-Earth orbit in the coming years — a figure that a new peer-reviewed study by the European Southern Observatory says would have devastating consequences for astronomy, potentially blinding the world's most powerful telescopes and permanently altering the night sky as humanity has known it for millennia.

The Numbers Behind The Crisis

SpaceX is the largest single driver of the problem. The company, which already operates thousands of Starlink satellites for internet connectivity, has filed plans with regulators to launch more than one million additional satellites — a proposed constellation described as a space-based data centre network. E-Space, a satellite startup, has proposed the Cinnamon constellation of hundreds of thousands of additional craft. China has two planned constellations, CTC-1 and CTC-2, that would add hundreds of thousands more. Perhaps most alarming to astronomers is Reflect Orbital, which has proposed 50,000 mirror-like satellites specifically designed to reflect sunlight back toward Earth at night — a commercial idea that would, as a side effect, make the night sky dramatically brighter for everyone on the planet.

What A ‘Safe’ Number Actually Looks Like

The ESO study, led by Olivier Hainaut — an astronomer with more than thirty years of experience at the observatory — modelled the impact of different satellite population scenarios on ground-based telescopes. His conclusion: no more than 100,000 satellites, all dimmer than naked-eye visibility at apparent magnitude 7 or fainter, could be accommodated without causing severe harm to astronomical observations. That figure — 100,000 — sounds large. Against a proposed total of 1.7 million, it is a ceiling that would be exceeded more than seventeen times over. The study has been accepted for publication in the journal Astronomy & Astrophysics.

What Happens To Our Best Telescopes

The study ran detailed simulations of what 1.7 million satellites would mean for specific observatories. The European Southern Observatory's Very Large Telescope — currently one of the most powerful optical telescopes on the planet — would lose up to 28 percent of its imaging capability to satellite trails, bright streaks caused by sunlight reflecting off satellite bodies passing through the telescope's field of view. The Vera C. Rubin Observatory in Chile, which is designed to survey the entire southern sky and is central to current plans for detecting near-Earth asteroids, would have most of its images rendered unusable for several hours every night during twilight periods when satellites catch sunlight while the sky is dark. The potential to detect hazardous asteroids — rocks that could threaten Earth — would be directly compromised.

Mirror Satellites: A Step Further

The Reflect Orbital proposal represents a qualitatively different threat from conventional satellite constellations. Where standard satellites leave bright trails across telescope images, 50,000 mirror-like craft designed to reflect sunlight would do something more fundamental: they would increase the overall brightness of the night sky by three to four times its current level. This is not a problem that can be solved by scheduling observations around satellite passes. A sky that is three to four times brighter at baseline means fainter objects — distant galaxies, faint exoplanets, the most ancient light in the universe — simply cannot be detected from the ground at all, regardless of how advanced the telescope. The FCC has received more than 1,500 formal comments on the Reflect Orbital application, the vast majority from the scientific community.

Regulators Are Still Catching Up

The FCC is currently reviewing both SpaceX's expanded Starlink application and the Reflect Orbital proposal, and has received more than 1,800 and 1,500 comments respectively. International bodies including the International Astronomical Union have called for binding regulations on satellite brightness, mandatory mitigation measures, and caps on total constellation sizes. So far, no binding global framework exists. Satellite operators are largely self-regulating, and the commercial incentives to launch more satellites — for internet coverage, data infrastructure, and the novel reflective-satellite business models — continue to drive expansion faster than regulatory responses can track.

Astronomy's Last Warning

Olivier Hainaut has described the current trajectory as a genuine point of no return for astronomy. Once 1.7 million satellites are in orbit — a process that, if current regulatory approvals continue, could unfold over the next decade — the damage to ground-based observation cannot be undone. The satellites will not be recalled. The night sky, once a commons shared by every human civilisation that has ever existed, will have been permanently altered by commercial decisions made by a handful of companies and approved by a single national regulator. The question, as Hainaut and his colleagues frame it, is not whether astronomy can adapt to some satellites. It is whether anyone with the authority to act will do so before the number crosses the threshold from manageable to catastrophic.