Artificial satellites come in many varieties and are placed at various altitudes, the lowest being the espionage satellites, which are primarily used for military surveillance. These spy satellites, in general, orbit at the lowest altitudes, with some merely a hundred or so kilometers above Earth, thus providing clear views of objects on the ground.
The typical civilian satellites remain geostationary in outer space and orbit at much higher altitudes, nearly a hundred times that of spy satellites, at minimum over ten thousand kilometers.
Those satellites used for scientific research and exploration, designed to observe outer space and study the mysteries of the universe, cannot simply be described by their altitude but rather by their 'distance from Earth.' The farthest satellites currently orbiting Earth can easily exceed fifty thousand kilometers, and some even approach a hundred thousand kilometers.