The Propulsion Module Subsystem provides thrust for spacecraft trajectory and orbit changes, and for attitude control. The main engine is used for spacecraft velocity and trajectory correction changes. There are two identical main engines, one in use and the other available as a backup. The engines use nitrogen tetroxide and monomethyl-hydrazine as the oxidiser and fuel, respectively. Each engine is capable of producing a thrust of 445 N.
There are also sixteen 0.5 N thrusters arranged in four groups of four, which are used for attitude control and also for small (< 0.5 m s-1) velocity-change manoeuvres. The thrusters use hydrazine fuel which undergoes catalytic decomposition to generate thrust.