DEFINITION: APOGEE AND PERIGEE


Some satellites have an elliptical orbit. For these types of orbit, there are two commonly used terms:

Apogee - This is the point at which the satellite is furthest from the Earth
Perigee - This is the point at which the satellite is closest to the Earth

 

The terms apogee and perigee are specific to Earth. When the reference point is the Sun, these points are instead called aphelion and perihelion. The general term that describes these point is called apsis, and for any reference objects, the points are called apoapsis or apocenter and periapsis or pericenter.

One important note is that the satellite travels more slowly at apogee than at any other point in orbit. Thus, when viewed from the Earth's surface, the satellite takes a long time to traverse the sky providing the user with a longer access or link time.

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