Sun Synchronous Orbit vs. Geosynchronous Orbit: Key Differences

This page compares Sun Synchronous Orbit and Geosynchronous Orbit, highlighting the key differences between them.

What is Sun Synchronous Orbit?

• A Sun Synchronous Orbit is an Earth satellite orbit with a near-polar orbital plane. Its altitude is carefully chosen so that the satellite passes over all locations on Earth at the same latitude twice in each orbit at the same local solar time.
• These orbits are designed to allow satellites to pass over a specific section of the Earth at the same time of day consistently.
• Because there are approximately 365 days in a year and 360 degrees in a circle, the satellite’s orbital plane must shift by approximately one degree per day.
• In essence, this is an orbit where the satellite’s orbital plane maintains a fixed orientation relative to the Sun.
• The orbit’s design ensures the angle between the orbital plane and the Sun remains constant, resulting in consistent lighting conditions for the satellite’s observations.
• This orbit typically lies at an altitude between 700 and 800 kilometers above the Earth.

Examples: Landsat series, SPOT series, IRS series, NOAA, SEASAT, TIROS, etc.

What is Geosynchronous Orbit?

• Geosynchronous satellites are synchronous with respect to the Earth. This means that from a fixed point on Earth, these satellites appear to be stationary.
• Each geosynchronous satellite covers approximately 1/3 (120 degrees of latitude) of the Earth’s surface.
• This orbit is located about 35,786 kilometers (22,236 miles) above the surface of the Earth.
• At this altitude, a satellite requires approximately 24 hours to orbit the Earth, which is the same time it takes for the Earth to complete one revolution around its axis. This synchronization gives the orbit its name: geosynchronous.
• Satellites in this orbit must travel at the Earth’s rotational speed and in the same direction (eastward).
• These satellites hover at a right angle above the equator, making them appear stationary in the sky when viewed from Earth. Because of this position, they always see the same section of the Earth’s surface.
• The inclination of a geostationary (a special case of geosynchronous) satellite with respect to the Earth must be zero.

Key Differences: Sun Synchronous vs. Geosynchronous Orbit

Here’s a summary of the key differences:

Sun synchronous orbit satellites are useful for monitoring activities near the poles, whereas geosynchronous orbit satellites provide a continuous view of a particular spot on the Earth’s surface.