ACS refers to Attitude Control System. Attitude control is the exercise of control over the orientation of the satellite and its components with respect to its target region of communication. ACS essentially orients and stabilizes the satellite such that there is effective alignment of the satellite antennas and the ground station. It also is responsible for damping the rotations that are created in the satellite due to varied external factors like the gravitational forces from the sun, moon and other planets; pressure on the solar panels, magnetic fields, etc.
ACS has two categories:
Elements of active control system are:
Elements of the passive control system are: