🛰️ This startup plans to send thousands of mirrors into orbit for continuous sunlight

The company Reflect Orbital plans to deploy a constellation of orbital mirrors designed to reflect solar light toward Earth during the night. This proposal deeply questions our relationship with the nocturnal environment and raises concerns.

This project fits into a perspective of artificially extending sunlight, with the stated goal of increasing solar energy production. The initial demonstration plans to launch a test satellite, Earendil-1, equipped with an 18-meter reflector. According to documents filed with U.S. authorities, this first step could precede the deployment of several thousand similar satellites by the end of the decade, forming an orbital infrastructure unprecedented in history.

The technical limits of an excessive ambition

The physical feasibility of the project encounters several fundamental obstacles. The orbital distance, combined with the apparent angular size of the Sun, implies an inevitable dispersion of the reflected radiation. A 54-meter mirror would produce a light spot on the ground at least 7 kilometers (about 4.3 miles) in diameter, with an estimated intensity 15,000 times lower than that of the midday Sun. This brightness, although greater than that of the full moon, remains far from the levels required for significant energy production.

Orbital dynamics introduces a second major limitation. At an altitude of 625 kilometers (about 388 miles), each satellite moves at over 7 kilometers per second (about 4.3 miles per second), maintaining its relative position above a given area for only a few minutes. To ensure continuous lighting for one hour, calculations indicate that several tens of thousands of mirrors would need to be deployed, far exceeding the current number of all operational satellites and cataloged space debris.

The ground tests conducted by the company, although demonstrating the basic optical principle, do not reflect the actual conditions of space. An experiment with a balloon using a 2.5-meter mirror can only transpose its results to reflectors of kilometer-scale dimensions in orbit, which are technologically unrealistic with current materials.

The environmental impact of an artificial sky

Professional astronomy would be the first affected by this project. Each orbital mirror, moving rapidly across the celestial vault, would create extremely bright light trails in observation instruments. Space.com reports the concerns of the Royal Astronomical Society, for whom the intentional illumination of the sky would represent a catastrophe for astronomical research, far more than the incidental light pollution from other satellite constellations.

Terrestrial ecosystems would also undergo profound disruptions. The organization BugLife emphasizes that the natural day-night cycle, a fundamental rhythm that has governed evolution for billions of years, would be deeply altered. Many species, from pollinating insects to migratory birds, depend on nocturnal darkness for their biological cycles and behaviors.

Human health could also suffer from this artificialization of the nycthemeral cycle. Studies cited by experts show links between light pollution and sleep disorders or depression, with an increase of nearly 10% caused by artificial nighttime lighting since the advent of LEDs.