# Impact of orbital mirrors on night sky visibility

> Live situation record from CLSTR: https://clstr.news/situations/impact-of-orbital-mirrors-on-night-sky-visibility
> Updated: 2026-09-03T14:50:32.000Z. Sources: 5. Developments: 2.

Researchers from the Slovak Academy of Sciences, Comenius University, and Princeton University have released models detailing the atmospheric impact of orbital mirrors. The study warns that such technology could significantly obscure the night sky, noting that a single large mirror could produce illumination levels comparable to a street lamp, rendering stars invisible within a radius of several dozen kilometers.

Specifically, a planned 54-meter mirror is projected to appear 40 times brighter than a full moon, potentially creating a visible light pillar from 34 kilometers away. These findings come as the American company Reflect Orbital prepares to launch the EARENDIL-1 pilot satellite, an 18-by-18-meter mirror designed to reflect sunlight from an altitude of approximately 600 kilometers. This pilot project is intended as a precursor to a proposed constellation of roughly 50,000 larger mirrors.

## Timeline

### 2026-09-03: Scientists warn orbital mirrors could obscure the night sky

Researchers from Slovakia and the US warn that orbital mirrors could cause massive light pollution, making stars invisible for dozens of kilometers by illuminating the Earth's atmosphere.

3 sources. https://clstr.news/cluster/scientists-warn-orbital-mirrors-could-obscure-the-night-sky

### 2026-08-31: Light pollution impacts astronomy and ecosystems

Light pollution from artificial sources is obscuring the night sky and disrupting ecosystems. The Earth Night initiative promotes reducing unnecessary lighting, with its next event set for September 2026.

2 sources. https://clstr.news/cluster/light-pollution-impacts-astronomy-and-ecosystems

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Cite as: Impact of orbital mirrors on night sky visibility. CLSTR, https://clstr.news/situations/impact-of-orbital-mirrors-on-night-sky-visibility