Ion engines are a type of electric propulsion system that generate thrust by accelerating ions. They work by using electricity to ionize a propellant, typically a gas like xenon, and then expelling these ions at high speeds. This process creates a small but continuous thrust, making ion engines highly efficient for long-duration space missions. Unlike traditional chemical rockets, which burn fuel to produce thrust, ion engines use much less propellant over time. This efficiency allows spacecraft, such as those used in NASA missions, to travel further into space while conserving fuel, making them ideal for deep-space exploration.