Ion thruster
Ion thrusters are good for travelling between things in space that are very far away from each other. One example of this is interplanetary travel. Ion thrusters are good for this because they are efficient and can thrust for very long times. Chemical rocket thrusters ("regular" rocket thrusters) can only burn for short times, because they use fuel quickly and not efficiently. Because of this, chemical rockets only thrust for short times at important places during the journey. Ion thrusters use fuel very slowly and very efficiently. This means that ion thrusters can thrust continuously for the entire journey. In a slightly surprising way, this makes spacecraft that use ion thrusters faster than spacecraft that use chemical rockets.