Polar orbit

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A satellite in a polar orbit passes above or nearly above both poles of the planet (or other celestial body) on each revolution. It therefore has an inclination of (or very close to) 90 degrees to the equator.

Since the satellite has a fixed orbital plane perpendicular to the planet's rotation, it will pass over a region with a different longitude on each of its orbits.

Polar orbits are often used for earth-mapping-, earth observation- and reconnaissance satellites, as well as some weather satellites. The disadvantage to this orbit is that no one spot on the Earth's surface can be sensed continuously using this orbiting method.

To face one polar area a large part of the time, albeit at a large distance, an elliptic orbit with a high eccentricity with apogee above that area, is applied: a Molniya orbit.