Geostationary constellations cannot provide broadband internet because of their orbit 35,000 kilometers from earth. Each one-way takes 116 milliseconds (35.000,000 m / 299 792 458 m/s = 116 ms). This route is doubled and more as the signal returns from space, then terrestrial and subsea cables to the most proximal data center. This trip length causes an average minimum 600 ms latency––too latent for zoom etc.
LEO constellations are 60x closer and can offer 25 ms latency. Starlink is currently 550 km.
The largest LEO satellite constellations are below, sorted by launched satellites.
|No. of LEO satellites in orbit Feb-2022||No. of LEO satellites planned||Altitude in kilometers||Satellite service life in years|
|SpaceX Starlink||2,000||4,408||540 – 570||5 – 7|
|Amazon Kuiper||578||3,236||590 – 630||5 – 7|
|Telesat||298||1,671||1,015 – 1,325||10|
Elon loves strategic moats, and Starlink has a massive one. Because of atmospheric drag, LEO satellites lifespan is 1/3 that of GEO satellites. This is a moat for Starlink. SpaceX can inexpensively subsidize Starlink launches by filling unused cargo capacity with Starlink satellites. They are modular. No other constellation has this competitive advantage, and the moat widens as constellations grow in capacity, and become more expensive to maintain.
Note: This write-up excludes LEO constellations not engaged in broadband Internet connectivity. Thank you MIT, for An Updated Comparison of Four Low Earth Orbit Satellite Constellation Systems to Provide Global Broadband.
Next, the tech leaps changing the economics for satellite broadband.