Why are satellites launched into space?
Satellites can be grouped by the jobs they do. Some look down at Earth. These include spy satellites, weather observers, and resource satellites that scan Earth for evidence of valuable deposits of minerals, large schools of fish in oceans, crop yields. Some study the space around them. These include those looking at the Earth’s magnetic field, the solar wind, and similar matters. Others look outward. These may study the Sun in various ways, or they function as telescopes looking at solar system objects, stars, nebulas, galaxies, etc. Any of the above may use visible light or function in UV, IR, radio, gamma ray, x-ray, etc wavelengths. Finally, and economically very important, there are communications satellites that carry telephone, radio, TV, and computer data around the world. Over 8000 satellites have been launched since October 4, 1957. The largest number were launched by the old Soviet Union, which at one point was launching one every three days.
