Spacecraft Electric Propulsion: The Xenon Ion Engine Prototype
A xenon ion engine prototype, photographed through a port of the vacuum chamber where it was being tested at NASA’s Jet Propulsion Laboratory, shows the faint blue glow of charged atoms being emitted from the engine. This prototype will provide data for successive ion engines to be used in future space missions.
Now that the engine has been ground-validated by the test, a similar engine will power the New Millennium Program’s first mission, Deep Space 1, designed to provide space validation for this and other important technologies. DS1 will use the xenon ion engine in a test mission to encounter an asteroid, Mars and a comet.
The engine, weighing 17.6 pounds (8 kilograms), is 15.7 inches (40 centimeters) in diameter and 15.7 inches long. The actual thrust comes from accelerating and expelling positively charged xenon atoms, or ions. While the ions are fired in great numbers out the thruster at more than 110,000 kilometers (68,000 miles) per hour, their mass is so low that the engine produces a gentle thrust of only 90 millinewtons (20-thousandths of a pound). Thus, it requires patience to accumulate the great speeds which ion propulsion is capable of achieving.