What is a mega-constellation?
A mega-constellation is broadly defined as a satellite network comprising hundreds to thousands of coordinated spacecraft in low Earth orbit, operating as a single broadband system. The term emerged in the 2010s to describe a new generation of LEO internet projects fundamentally different in scale from earlier constellations like Iridium (66 satellites).
The operational systems
As of 2026, SpaceX Starlink is the dominant mega-constellation with over 10,000 satellites in orbit, serving more than 10 million customers in approximately 150 countries. Eutelsat OneWeb operates 648 satellites at 1,200 km. Amazon Kuiper is ramping toward its first commercial services with an authorisation for 3,236 satellites. Telesat Lightspeed targets ~298 MEO satellites for its enterprise-focused constellation.
Regulatory and interference challenges
ITU filing procedures were designed for small fleets of GEO satellites, not systems filing for 30,000 spacecraft. The ITU now enforces milestone requirements — operators must launch a defined percentage of their authorised constellation within set timeframes or lose coordination priority. Frequency coordination between mega-constellations sharing Ka and Ku bands is an active regulatory challenge at the ITU.
Environmental impact
Mega-constellations have raised concerns from astronomers: sunlight reflected off hundreds of low-altitude satellites creates streaks in long-exposure telescope images. Atmospheric re-entry of aluminium-bodied satellites deposits metallic vapour in the upper atmosphere whose long-term effects are still being studied. Most operators have committed to post-mission disposal within 5 years of end of life.