Moon is a natural satellite of earth. However we are not interested in the natural satellites. An artificial satellite orbits or revolves around the earth in exactly the same manner as electrons revolve around the nucleus of an atom. The paths in which satellites move are called as orbits. The orbits are of different types such as synchronous orbits, polar orbits and inclined orbits, out of which the synchronous or geostationary orbit is used by the geostationary satellites.

The satellites can be used for variety of purposes. Depending on the type of application, the satellites are classified into the following categories.

  1. Communication satellites.
  2. Remote sensing satellites.
  3. Weather satellites.
  4. Scientific satellites.