4. The polar orbit

As the name suggests, polar orbits pass over the Earth’s polar regions from north to south. The orbital track of the satellite does not have to cross the poles exactly for an orbit to be called polar, an orbit which passes within 20 to 30 degrees of the poles is still classed as a polar orbit.

MetOp's polar orbit

Polar orbits are used for reconnaissance and Earth observation. If a satellite is in polar orbit at an altitude of 800 km, it will be travelling at a speed of approximately 7.5 km per second.

These orbits mainly take place at low altitudes of between 200 to 1000 km. Satellites in polar orbit look down on the Earth’s entire surface and can pass over the North and South Poles several times a day.

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