Scientific American (6 November 2025)

Seeking Profits, Private Companies Look to Light up the Night Sky

If the company’s plans come to fruition, following its tests next year it will begin launching more mirror-toting satellites, ultimately building a mega constellation of 4,000 by 2030. Each would be capable of casting a 5 km-wide beam about four times brighter than the full moon down to Earth. But atmospheric scattering would ensure that some light escapes each beam, says John Barentine, a Tucson, Ariz.–based astronomer and executive officer of Dark Sky Consulting, which advises companies and city officials on outdoor lighting use. “We’ve calculated that, even relatively far from the beam, the [satellites] would still have an apparent brightness that would make them among the brightest objects in the night sky,” he says.

Read more: https://www.scientificamerican.com/article/alarm-grows-over-proposed-giant-mirrors-in-orbit-and-other-commercial-space/