Why do satellites come in a variety of shapes?

There are many types of satellites according to the purpose. Earth observation satellite, communications satellite, broadcasting satellite, weather observation satellite, geodetic satellite, scientific satellite… Satellites are developed and launched with their own purpose. In other words, each satellite has precise design depend on its purpose, that’s why satellites come in a variety of shapes.

For example, even in case of the Earth observation satellites that have the same target (the Earth), if the observation areas or orbits are different, observation instruments and environmental conditions are also different. So, the shapes of the satellites are also different accordingly. Some satellites equip a big solar array paddle on one side, others equip the paddles on both sides. There is a satellite which has solar array paddles facing different directions on each side… Please compare the shapes of various satellites.