Orbital Dynamics by NASA

This excellent web site from NASA explains a lot about how orbits work.

A geosynchronous orbit at an altitude of 35,786 kilometers (above sea level) allows a satellite to orbit at the same rate the Earth turns, so it always remains over the same spot on the planet below.

Lagrange points are orbital sweet spots where gravity from several objects balance each other, allowing an object to remain in a stable position.

Catalog of Earth Satellite Orbits – [nasa.gov]

Just as different seats in a theater provide different perspectives on a performance, different Earth orbits give satellites varying perspectives, each valuable for different reasons. Some seem to hover over a single spot, providing a constant view of one face of the Earth, while others circle the planet, zipping over many different places in a day.

There are essentially three types of Earth orbits: high Earth orbit, medium Earth orbit, and low Earth orbit. Many weather and some communications satellites tend to have a high Earth orbit, farthest away from the surface. Satellites that orbit in a medium (mid) Earth orbit include navigation and specialty satellites, designed to monitor a particular region. Most scientific satellites, including NASA’s Earth Observing System fleet, have a low Earth orbit.

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