There are several reasons why you want to study the orbits of satellites:
There are 8 elements that you need to define an orbit. These elements are also called Keplerian Elements after the German astronomer Johannes Kepler (1571-1630). Kepler discovered that planets moved in elliptical orbits rather than circular orbits. The following are Keplerian Elements:
as the satellite gets closer to the Earth, its velocity increases. If we know how fast the satellite is going, we also know the altitude of the satellite.
To learn about types of orbits, click here.
There are several satellite tracking programs that people can download free of charge: