Satellite Constellations
A satellite constellation is a group of satellites working together as one system. AstroSat lets you explore the major constellations on a live 3D globe — and group any satellites you like into constellations of your own.
Constellations you can explore
Space Stations
The International Space Station, China's Tiangong and other crewed platforms — the brightest and easiest objects to spot from the ground.
Starlink and OneWeb
The two largest low-Earth-orbit broadband networks. Starlink is the biggest constellation ever flown and is responsible for the "train" of lights seen after a fresh launch.
GPS and Galileo
The American and European satellite navigation systems, flying in medium Earth orbit roughly 20,000 km up — far higher than the broadband fleets.
Iridium, Cosmos, Molniya
The Iridium NEXT communications fleet, the long-running Soviet and Russian Cosmos series, and Molniya satellites on their distinctive highly elliptical orbits.
Constellations exist because a single satellite can only do so much. One spacecraft in low Earth orbit is over any given point for a few minutes at a time, so continuous global coverage — internet, navigation, messaging — requires many satellites in a coordinated pattern of orbital planes. Navigation systems such as GPS and Galileo need at least four satellites visible from anywhere on Earth to fix a position, which is why they fly in medium Earth orbit where each one sees a large area. Broadband constellations take the opposite approach: thousands of satellites flying low, where the round trip to the ground is short enough for responsive internet, at the cost of needing far more of them. On AstroSat you can filter the globe to any of these fleets, watch the geometry that makes them work, and build your own groups from the satellites you care about.
Frequently asked questions
What is a satellite constellation?
A group of satellites operated together as a single system, arranged so their coverage overlaps — for example GPS for navigation or Starlink for internet.
Which constellations can I track here?
Space stations, Starlink, GPS, Galileo, OneWeb, Iridium NEXT, Cosmos and Molniya, plus any custom group you create.
Which constellation has the most satellites?
Starlink, by a wide margin — it is the largest satellite constellation ever deployed and continues to grow with regular launches.
Can I build my own constellation?
Yes. You can group any satellites you like into a custom constellation and filter the globe to just that group.