http://www.space-travel.com/reports/Scientists_develop_new_plasma_thruster_999.html Scientists develop new plasma thruster U.S. scientists say they are developing a new type of rocket that runs on gases that are much less expensive than conventional propellants. Massachusetts Institute of Technology researchers say their new rocket -- called the Mini-Helicon Plasma Thruster -- is much smaller than other rockets of its kind and could consume just one-tenth the fuel used by conventional systems. Oleg Batishchev, who led the research, said propulsion systems currently used for maintaining a satellite's orbit rely on chemical reactions that occur within the fuel, releasing energy that ultimately propels the object. But such chemical rockets are expensive, due largely to the amount of fuel they use. Now, he said, engineers are developing alternative, non-chemical rockets in which an external source of electrical energy is used to accelerate the propellant that provides thrust. The scientists said the Mini-Helicon is the first rocket to run on nitrogen, the most abundant gas in Earth's atmosphere. Batishchev noted, however, it could be years before the technology can be used commercially. This work was funded by the Air Force Research Laboratory.