Types of Orbits: What is Low Earth Orbit (LEO)? LEO/MEO/GEO

Satellites circle the Earth on various paths based on their applications, altitudes, and coverage. The primary types of orbits are:

1. Low Earth Orbit (LEO):

Altitude: 160–2000 km above the Earth

Characteristics: Short orbital period (~90–120 minutes), moving fast

Applications: Earth observation, remote sensing, weather satellites, and some communication satellites (Starlink).

2. Medium Earth Orbit (MEO):

Altitude: 2000–35,786 km

Characteristics: Longer orbital period than LEO, stable for navigation satellites.

Applications: GPS, GLONASS, Galileo navigation satellites.

3. Geosynchronous orbit (GSO):

Altitude: ~35,786 km

Characteristics: Returns to the same position in the same time every day.

Applications: Weather forecasting, communication satellites.

4. Geostationary Orbit (GEO):

Altitude: ~35,786 km, directly above the equator.

Characteristics: Appears to be stationary in relation to the Earth; orbital period = 24 hours.

Applications: Television, internet, and long-distance communication satellites.

NOTE: While all GEO satellites are geosynchronous, not all geosynchronous satellites are GEO as they can be in inclined orbits that would cause the satellite to “figure-eight” in the sky.

5. Sun-Synchronous Orbit (SSO):

Altitude: ~600–800 km (typically LEO).

Characteristics: Passes over the same part of Earth at the same local solar time.

Applications: Remote sensing, Earth observation, and spy satellites.

6. Polar Orbit:

Path: Passes over the poles of the Earth.

Characteristics: Can cover the entire surface of the Earth over multiple orbits.

Applications: Earth mapping, reconnaissance, and monitoring of the climate/weather.

7. Transfer Orbits:

Example: Geosynchronous Transfer Orbit (GTO).

Purpose: Transfer orbit models how to place a satellite into a final operational orbit.