Every satellite has a bus and payload. The bus is the body of the satellite and is managed by the satellite control operations to maintain a desired location. It carries the payload and is composed of a number of subsystems, such as the power supply, antennas, and mechanical and thermal control equipment. The bus also provides electrical power, stability, and propulsion for the entire satellite. The payload includes the devices the satellite needs to perform its mission. This configuration differs for every type of satellite. For example, the payload for a weather satellite could include cameras to take pictures of cloud formations, while the payload for a GPS satellite would include equipment to pass navigation information from the satellites to receivers on Earth. Monitoring and operating of the satellite payload is done to collect data or provide a capability to the warfighter or civilian user.