Ion Propulsion

Ion engines are a special kind of spacecraft engine. They use electricity to shoot tiny charged particles, called ions, out the back of the spacecraft. The push from an ion engine is very gentle, about as strong as the weight of a sheet of paper on your hand. But because it can run for months or years, it can eventually push a spacecraft to incredible speeds.

How Ion Engines Work

An ion engine uses electricity, often from solar panels, to charge atoms of a gas like xenon. The charged atoms, called ions, are pushed out the back of the engine at very high speed. This creates a small but constant thrust. Over many months, this tiny push adds up. An ion engine uses much less fuel than a regular rocket engine.

Where Ion Engines Are Used

NASA's Dawn spacecraft used ion engines to visit two asteroids. The Deep Space 1 mission tested ion propulsion in the late 1990s. Many satellites use small ion thrusters to stay in the right orbit. Ion engines are perfect for long missions in deep space where they have plenty of time to build up speed.

Fun Facts

• NASA's Dawn spacecraft used ion propulsion to visit both the asteroid Vesta and the dwarf planet Ceres.
• An ion engine can run for years, much longer than a chemical rocket that burns out in minutes.
• The blue glow of an ion engine comes from the charged xenon gas being pushed out at high speed.

Did You Know?

Ion engines are 10 times more efficient than regular chemical rockets. This means a spacecraft can travel much farther on the same amount of fuel.