They're not perfect, though, and the most extreme maneuver can still get past these important devices. Repulsorlifts need a large mass to push against in order to work. They don't work in empty space because there's nothing to push against. Because it's gravity that repulsorlifts push against, they're also called anti-gravity engines. Vehicles like landspeeders and speeder bikes use these engines to move across a planet's surface.
All space combat occurs with sublight drives.
Sublight drives are called that because they move a ship slower than the speed of light. One type of sublight drive is an ion drive . It works by shooting tiny particles called ions out the back of the ship, which pushes the ship forward. Some vessels have smaller engines that help move the ship from side to side. These lateral thrusters make a ship easier to maneuver, and harder to hit with weapons.