1. An R-4D bipropellant rocket motor and four XIPS-25 ion engines provide propulsion. 2. The focus of this mission phase was on the ion engine systems. 3. This could work well with an ion engine , for example, as mentioned previously. 4. This kind of slow, patient acceleration means that ion engines are extremely efficient. 5. Star Wars films and literature refer to twin ion engines ( TIE ) starfighters. 6. Ion sources are used to form ions for ion engines . 7. The space probe would be powered by an ion engine . 8. Ion engines can make much more efficient use of propellant than existing chemical rockets.9. Another promising technology, tested on " Deep Space 1 ", is the ion engine . 10. The spacecraft features ion engines , upgraded guidance and navigation technology, antennas and attitude control systems.
