Attitude Determination and Control System (ADCS)
ADCS is an inclusive system of sensors (magnetometer, sun sensors), actuators (torque rods, reaction wheels), and all the operational control that happens in between.
A spacecraft’s ADCS determines the orientation (attitude) of the spacecraft in orbit and will use actuators to maneuver it into the desired position. These systems have become important solutions for hardware-constrained small satellites that need the control to point antennas at ground stations and position solar arrays toward the sun.