What is the function of the Attitude Determination and Control System (ADCS)?

• A. To determine spacecraft orientation and adjust its attitude using sensors and actuators.
• B. To compute orbital elements.
• C. To manage power distribution.
• D. To handle thermal control.

Answer: (A)

Attitude determination and control is the part of a spacecraft that figures out which way it is pointing and then uses devices to steer its orientation to the desired direction. It starts by measuring orientation with sensors such as star trackers for precise absolute attitude, sun sensors or horizon sensors for reference, and gyroscopes to track how fast the spacecraft is rotating. A computation or estimation step combines these measurements to determine the current attitude and angular velocity. Based on a target attitude, control actuators are commanded to apply torque and adjust orientation—using reaction wheels, control moment gyroscopes, thrusters, or magnetic torquers as appropriate. This capability is essential for pointing antennas, instruments, and solar panels, as well as for performing precise reorientations and stabilizing the spacecraft.

The other functions listed belong to different systems: orbital elements are determined by guidance/navigation for the spacecraft’s path around the planet, power distribution manages electrical power, and thermal control handles temperature management.