Why satellites live at different altitudes
Fly low and you answer in an instant but see only a small patch. Fly high and one satellite blankets a third of the planet — at the cost of distance.
Orbit distances are approximately to scale.
Quick, sharp communication. But each satellite sees only a small patch and races overhead — so you need thousands of them.
One satellite blankets nearly a third of the planet and hangs fixed overhead. The cost is distance — every signal lags.
Signal delay is just distance divided by the speed of light, so a low satellite answers almost instantly while a distant one lags. Coverage is the mirror image: a high satellite sees a huge, fixed slice of Earth, while a low one sees only a small footprint and crosses the sky roughly every 90 minutes. Pick low for speed, high for reach — no single satellite gives you both.
| Orbit | Altitude | Signal delay | Coverage / sat | Sats for global |
|---|---|---|---|---|
| LEO | 160–2,000 km | ~2 ms | small, moving | hundreds–thousands |
| MEO | 2,000–35,786 km | ~30–70 ms | regional | ~24 |
| GEO | 35,786 km | ~120 ms | ⅓ of Earth, fixed | ~3 |
Signal delay shown represents one-way travel from ground to satellite. A full internet “ping” (User → Satellite → Gateway → Satellite → User) is roughly 4× this physical delay, plus hardware routing and processing time.
Close means fast and sharp — ideal for interactive internet and high-resolution imaging. The catch: tiny field of view and constant hand-offs, so it takes a huge constellation. Starlink, OneWeb, the ISS.
The middle ground. High enough that ~24 satellites blanket the planet with strong geometry, low enough to stay responsive. This is where navigation lives — GPS, Galileo, GLONASS, BeiDou.
At this exact height a satellite circles once a day, so it appears fixed overhead — your dish just points at one spot forever. Perfect for broadcast and weather; the price is distance-driven lag. TV, GOES, Inmarsat.
Filter the constellations directory by orbit class to see who actually flies where — LEO, MEO or GEO.
open orbit · concepts. Figures are order-of-magnitude for teaching; exact values vary by satellite.