A picture of a satellite. (Courtesy to Microsoft Encarta for this photograph.)

Satellites are objects that orbit another object in space. They can be either man-made or not. In this lesson I will talk about the man made satellites. They orbit the earth and the sun. They are highly specialized tools that do different tasks every day.

There are many different types of satellites that can do different things. Weather satellites take pictures of how the weather is. Communications satellites transmit TV or telephone signals to Earth.

Each satellite has many different parts, but the two parts that all satellites are the payload and the bus. A payload is all the equipment a satellite needs to do its job. It can be cameras, antennas, electronics, and radar. The payload is different for every satellite. The payload for a weather satellite might include cameras to take pictures of cloud formations, while the payload for a communications satellite has big antennas to transmit TV or telephone signals to Earth. The bus is the part of a satellite that carries the payload and all of its equipment into space. It holds all the satellite's parts together and provides electrical power, computers, and propulsion to the spacecraft.

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