A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held.
Bus-derived satellites are less customized than specially-produced satellites, but have specific equipment added to meet customer requirements, for example with specialized sensors or transponders, in order to achieve a specific mission.
[1][2][3][4] They are commonly used for geosynchronous satellites, particularly communications satellites, but are most commonly used in spacecraft which occupy low Earth orbit missions.
Some satellite bus examples include: A bus typically consists of the following subsystems:[6]