A private US company plans to launch a test satellite to reflect sunlight to Earth, sparking concerns from astronomers about light pollution and the lack of global regulation.

The US company Reflect Orbital plans to launch a test satellite, Eärendil-1, later this year to demonstrate technology for reflecting sunlight to Earth on demand. The project, which received Federal Communications Commission approval in July, aims to extend daylight hours for uses such as solar energy, emergency response, and military operations. Astronomers warn that the satellites could significantly brighten the night sky, potentially disrupting research and the natural environment.

Potential Impact on Night Skies

A study by researchers at the Slovak Academy of Sciences, published in Astrophysical Journal Letters, suggests that a single Reflect Orbital satellite could appear 40 times brighter than the full moon within its target area. The study further calculates that a planned fleet of 400 satellites could create a combined beam as bright as 10,000 full moons, with light scattering affecting areas far beyond the intended target.

Regulatory and Safety Concerns

In August, groups including DarkSky International and the American Bird Conservancy requested that the FCC reverse its approval of the Eärendil-1 satellite, citing concerns for wildlife, aviation, and astronomy. Legal experts note that while the FCC regulates radio frequencies for spacecraft, it lacks clear authority to regulate the operation of the solar reflectors themselves. Reflect Orbital CEO Ben Nowack disputes the study's findings, stating that the company has implemented safeguards and engaged with scientific feedback.