The Impact of Computing Data Centres Orbiting Earth

Abstract

Artificial intelligence is projected to increase U.S. data centre power demand beyond 100 gigawatt by 2035 and global demand toward 1 terrawatt. In response, companies and governments have proposed placing computing infrastructure in sun-synchronous low-Earth orbit, where continuous sunlight could supply electrical power. Generating 5 GW would require solar arrays 4 x 4 kilometers in size. Although technically feasible, such structures at roughly 500 km altitude would dramatically alter both the night and daytime sky. A 4 x 4 km array in low earth orbit would span about 0.4 degrees, comparable to the Moon, and reflected sunlight would make it shine at magnitude g = -5 to -7 mag, 100 times brighter than the brightest stars. Dozens of these structures would appear as a north-to-south chain of industrial objects across the sky, visible for about 1 1/2 hours after sunset and 1 1/2 hours before sunrise. They would block stars, planets, and deep-sky objects for minutes at a time, while increasing the likelihood of collisions that could trigger runaway debris production. These orbiting computing facilities therefore pose serious astronomical, technical, and cultural concerns.

Submitted to Letters of the Monthly Notices of the Royal Astronomical Society