Polar Orbits

The Polar Orbit is not much suitable for communication purposes because it moves in a different direction than that of direction of earth’s rotation. So, the use of Polar satellites depends upon their arrival at a particular point on earth at a particular point. The Polar orbits are used for special applications like navigational satellites.

Key features of Polar Orbits

• Polar orbits are useful in earth mapping
• A satellite in polar orbit would pass over equator on different longitude in successive times.
• No one spot on the Earth’s surface can be sensed continuously from a satellite in a polar orbit, however, to make them work on a particular area, they are launched in highly elliptical orbit with its apogee over that area

In a polar orbit, the satellite passes above or nearly above both poles of the earth being orbited on each revolution. So, we can say that the inclination of such orbit is almost 90 degrees to the equator. The Polar orbits are used for earth-mapping, earth observation, and reconnaissance satellites, as well as for some weather satellites. However, Iridium satellite constellation also uses a polar orbit to provide telecommunications services.

Some important notes about Polar orbits

• Except for polar geosynchronous orbit, a satellite in a polar orbit will pass over the equator at a different longitude on each of its orbits.
• No one spot on the Earth’s surface can be sensed continuously from a satellite in a polar orbit, this is its biggest drawback.
• The polar orbit can be manipulated also. If we want a satellite in polar orbit to remain hovering over a certain area for larger time, it can be placed in a highly elliptical orbit with its apogee over that area.