Reaction Wheel

A reaction wheel is a device used on spacecraft to control their orientation or pointing direction without using thrusters. It consists of a spinning wheel whose speed can be increased or decreased. When the wheel's spin rate changes, the spacecraft experiences a counteracting motion due to angular momentum, allowing precise adjustments in attitude. This method provides smooth, fuel-efficient control for maintaining or changing the spacecraft's direction, essential for tasks like pointing antennas, cameras, or scientific instruments accurately in space.