All ships have some form of engine to propel themselves at less than light speed. Trying to park or maneuver through asteroid belts at light speed isn't really an option. These engines are classified as sublight engines. Though the method of propulsion can vary, they universally draw large amounts of power from the ship's power core to operate. These are the only engines capable of operating in strong gravitational or magnetic fields, so they must be used to get sufficiently far away from a planet to engage the light drives.
Not enough information for a detailed history as of yet.