Orbit selection of artificial earth satellite

The orbit of artificial earth satellite should be selected according to its mission and application requirements. For example, Earth resources satellites and photographic reconnaissance satellites that shoot the ground often adopt circular low orbits; In order to expand the detection range of space environment as much as possible, the satellite can adopt a flat elliptical orbit; In order to save the energy of launching satellites, satellites often adopt equatorial orbit and anterograde orbit; Satellites that conduct long-term continuous meteorological observation and communication in fixed areas often use geostationary satellite orbits; Satellites that need to observe the world repeatedly can adopt polar orbits. In order to make satellites always fly over a certain place on the earth at the same time, that is to say, in order to make satellites always pass through the same area under the same lighting conditions, it is necessary to adopt sun-synchronous orbit.