What are the main classifications of satellite orbits based on their altitude from Earth?

The question asks to classify satellites by how far out into orbit each one is. This refers to the altitude or distance from Earth. The most common and distinct classifications based on orbital distance/altitude are:

1. Low Earth Orbit (LEO): Satellites in this orbit are relatively close to Earth, typically between 160 km and 2,000 km in altitude.
2. Medium Earth Orbit (MEO): These satellites orbit at altitudes between 2,000 km and 35,786 km.
3. Geosynchronous Earth Orbit (GEO): Satellites in this orbit are at an altitude of approximately 35,786 km above the equator, matching Earth's rotation period. A special case is Geostationary Earth Orbit (GSO), which is a circular GEO directly above the equator.
4. Highly Elliptical Orbit (HEO): These orbits are highly elongated, meaning the satellite's altitude varies significantly, with a low perigee and a very high apogee.

These four categories represent the primary ways satellites are classified by their distance from Earth.

The final answer is $\text{4}$