In order to control spin, to execute maneuvers and make minor adjustments in trajectory, spacecraft are provided with sets of propulsive devices. These devices use either the hypergolic propellant or the monopropellant. Many if the activities of the propulsion subsystems are initiated by the attitude and articulation control subsystem.
Engines: It is a propulsive device, which is used to generate large amount of force necessary to maintain rocket stability.
Thrusters: It produces less force than engines and it is required for interplanetary trajectory correction maneuvers or spin control.
Propellant: The fuel and oxidizer burned to produce thrust in a rocket engine (see propellants).