Artificial satellites orbits in either Equatorial or Artificial or Polar orbits. Equatorial orbit is the orbit being parallel to the equator. In equatorial orbits, satellites do not need energy for revolutions. To make a satellite appearing stationary in space when viewed from the Earth, or called Geostationary, a satellite should be placed at about 35,786 km from the Earth surface. With that height, the satellite can have the revolution period of 24 hours, just like the Earth. Each corner of the earth can be connected by proper setting up of geostationary satellites.
Polar orbit is the orbit being parallel to the Meridian. Placed at 1,000 km above the Earth, a satellite takes 2 hours for revolution. Because these satellites complete a number of revolutions toward the Earth per day, their locations pass over at regular interval of time. For example, remote sensing satellites of India can pass over any locations on the earth every 21 days. Another example, American Landsat needs 16 days. The orbits of artificial satellites, like natural satellites, are elliptical. This is influenced by the gravity effect of the Earth.
