The cargo that the Shuttle carries into orbit or brings back to Earth is called its payload. The Shuttle has carried many different payloads. Some, such as the RMS, are attached payloads. They stay in the payload bay for the entire mission. Others are called free-flying payloads. Since 1998, the most common free-flying payloads brought into space by the Shuttle have been parts for the International Space Station.
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In its early days, the Shuttle would often carry an attached payload known as Spacelab. This was a laboratory in which the Shuttle crew members conducted scientific experiments. Spacelab hasnÕt been used since the International Space Station was put into orbit. The ISS crew is now able to conduct its own scientific experiments in space.
