What Is Ion Propulsion?
Ion propulsion involves the ionization of a gas to propel a craft. Instead of a spacecraft being propelled with standard chemicals, xenon gas (which is four times heavier than air) is given an electrical charge, or ionized. It is then electrically accelerated to a speed of about 25 miles per second. When xenon ions are emitted at such high speed as exhaust from a spacecraft, they push the spacecraft in the opposite direction.
