It circles the Earth in space along a path called an orbit. An artificial satellite may be designed in almost any shape such as a ball, drum, or box. It does not have to be streamlined because there is little or no air where it travels. A satellite's size and shape depend on its purpose.
Artificial satellites stay in space for varying lengths of time.
The lifetime of each satellite depends on its size and distance from Earth. When a satellite swings close to Earth, it runs into air which slows it. To stay in orbit, a satellite must maintain a certain speed. If it slows below this speed, it plunges into the atmosphere and burns due to friction. The gradual slowing of a satellite by air is called decay.