Since the launch of Sputnik in the 1950s, thousands of satellites have been put into orbit around the Earth and even other planets. Each has served a different purpose, from complex space stations like the International Space Station to the Global Positioning System. Most satellites can be considered to be “in space”, but in terms of the Earth’s atmosphere, they reside in either the thermosphere or the exosphere. The layer through which a satellite orbits depends on what the satellite is used for and what kind of orbit it has.
The thermosphere is a region of very high temperature that extends from the top of the mesosphere at around 85 kilometers up to 640 kilometers above the Earth’s surface. It is called the thermosphere because temperatures spike to thermal levels
Temperatures are highly dependent on solar activity, and can rise to 2,000 °C (3,630 °F). Radiation causes the atmosphere particles in this layer to become electrically charged (see ionosphere), enabling radio waves to bounce off and be received beyond the horizon. In the exosphere, beginning at 500 to 1,000 kilometres (310 to 620 mi) above the Earth’s surface, the atmosphere turns into space.
The highly diluted gas in this layer can reach 2,500 °C (4,530 °F) during the day.. (Source)