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(b) What kinds of orbits are assigned?

Satellite orbits are categorized by their shape (circular orbit, elliptic orbit), the altitude (low/medium, high), related position to the earth (polar orbit, Molniya orbit) , and related position to the sun (sun synchronous orbit).

The satellite on this orbit takes a position around the equator and moves at the same speed of the Earth's rotation

Sun-synchronous quasi-periodical orbit

This orbit is made by combining the synchronous orbit and quasi periodical orbit

Orbits other than 1 & 2

Non-synchronous orbit

1. The Geostationary orbit
The geostationary orbit is used for communication, broadcasting and weather satellites. This orbit takes a position around the equator at a distance of 36000km from the Earth's surface. Because the satellite moves at the same speed as the Earth's rotation, the satellite maintains the same position over a certain point of the Earth's surface. This orbit is useful for "serving at all times in a certain area" such as communication, broadcasting, weather forecasting missions. But these satellites can not be used on the opposite side area of the Earth.
"Himawari" (Japanese weather forecasting satellite) is assign ed to this orbit.

2. Sun -synchronous quasi periodical orbit
This orbit is made by combining the synchronous orbit and the quasi periodical orbit, and many Earth observation satellites employ this orbit. The satellite on this orbit passes by a certain place of the Earth's surface at the same local solar time (the orbit plane keeps a constant solar angle), so the satellite observes the same sun light reflection from the Earth's surface. This enables the observed images of each place to be easily compared and analyzed with the same sun light reflection phenomena. The satellite on this orbit observes all Earth surfaces , so they are utilized in all areas of the world. Also, the satellite on this orbit has a regression cycle in which the satellite passes the same place after respective pass cycles. Then this satellite observes the certain place with the same local solar time and same orbit position for each respective pass cycles. "DAICHI" (Japanese Advance d Earth Observing Satellite) and the "LANDSAT" series use this orbit.

3. Other orbits
The Tropical Rainfall Measuring Mission (TRMM) satellite is assign ed to an orbit that observes all tropical regions along the equator at various local solar times.
The orbit is selected for the purpose of its mission.

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