Satellite mirrors could threaten night skies and ecosystems, scientists warn

Plans to launch reflective satellites and up to 1 million additional spacecraft in low Earth orbit could disrupt human sleep, wildlife, and ecosystems, scientists have warned.

“The proposed scale of orbital deployment would represent a significant alteration of the natural night-time light environment at a planetary scale,” said the presidents of four international chronobiology societies, according to The Guardian.

Charalambos Kyriacou, a geneticist at the University of Leicester and president of the European Biological Rhythms Society (EBRS), added: “We’re saying, please think before you go through with this, because this could have global implications for things like food security. Plants need the night. You can’t just get rid of it.”

Reflect Orbital aims to beam sunlight onto 5- to 6-kilometer (3.1-3.7-mile) areas “on demand,” while Elon Musk’s company SpaceX plans up to 1 million satellites for a solar-powered AI network.

“While ideas like mirrors on satellites beaming ‘sunlight on demand’ … may sound like science fiction, these proposals are very real,” said Ruskin Hartley of DarkSky International.

Miroslav Kocifaj of the Slovak Academy of Sciences added that satellite reflections already raise night sky brightness and could approach thresholds set to preserve dark skies by 2035.

Tami Martino, head of the Canadian Society of Chronobiology, said: “Circadian systems are sensitive to light levels far below what humans typically perceive as bright. If the night sky becomes permanently brighter, the consequences could ripple through ecosystems in ways we do not yet fully understand.”