Researchers are working to develop new ion thrusters that can harvest vital electrons from electrified carbon nanotubes, rather than from precious xenon gas propellant.
The researchers are focusing their effort on so-called Hall effect thrusters, which are used today in at least a dozen U.S. satellites and many Russian satellites. These ion thrusters typically have a single, hollow cathode that holds part of the propellant used for creating electrons.
http://www.msnbc.msn.com/id/33869995/ns ... ence-space