What is the role of propulsion systems in controlling a spaceship’s direction and speed?

Propulsion systems are essential for controlling a spaceship’s movement in the vacuum of space. Once in orbit, small thrusters (reaction control systems) adjust the spacecraft’s orientation, direction, and speed. These thrusters use gases like hydrazine or xenon expelled at high velocity, following Newton’s third law—every action has an equal and opposite reaction. For long-distance travel, more efficient engines such as ion thrusters or electric propulsion systems are used, providing steady but continuous acceleration over time. The propulsion system also performs course corrections, orbital adjustments, and deorbiting maneuvers, ensuring precise control and navigation across vast distances.