This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A new paper has put hard numbers on a plan that's been rattling around the astronomy community for a while now—a California company called Reflect Orbital wants to put giant mirrors in orbit and beam sunlight down to Earth after dark. The work is published on the arXiv preprint server and has been accepted for publication in Astrophysical Journal Letters.
Their pilot satellite, Eärendil-1, carries an 18-by-18-meter (59-by-59-foot) reflector at roughly 600 kilometers (370 miles) altitude and is designed to throw a 2.5-kilometer (1.6-mile) patch of daylight onto a chosen spot on the ground whenever a customer wants it. Solar farms working through the night, disaster zones lit for rescue crews—that's the pitch. Eärendil-1 is the test article for a proposed constellation of around 50,000 of these things, the larger production versions stretching to 54 by 54 meters (177 by 177 feet) apiece.
The team behind the new paper, led by researchers including Gáspár Bakos, did the atmospheric physics properly. They modeled how sunlight bouncing off a single mirror would scatter through the air, both the direct beam and the glow it throws off into the surrounding sky through Rayleigh and aerosol scattering. Anyone standing in the beam of one 54-meter satellite would see it as a point of light roughly magnitude -16.7, about four magnitudes brighter than a full moon.
From 14 kilometers (9 miles) away, the scattered glow alone would outshine full moonlight across most of the sky, and you'd still notice it as brighter than moonlight from 34 kilometers (21 miles) out. The diffuse background would resemble dusk shortly after sunset, bright enough to wash out every star but the very brightest. Run 400 of these mirrors on the same patch at once, which the company's long-term plans essentially call for, and the glow becomes obvious from 80 kilometers (50 miles) away.
This isn't really a story about one satellite. It's a story about who gets to decide what the sky looks like. Eärendil-1 already cleared the FCC in July, over more than 1,800 public comments and formal objections from the American Astronomical Society and dark-sky groups, on the reasoning that light pollution and astronomical interference simply aren't the FCC's problem to regulate.
Nobody else has claimed that job either. Miroslav Kocifaj et al, Atmospheric Light Pollution by Proposed Reflect Orbital Space Mirrors, arXiv (2026). DOI: 10.48550/arxiv.2608.06433 Journal information: Astrophysical Journal Letters , arXiv BSc Life Sciences & Ecology.
Extract — continue reading at the source.
