Message #18995

[Bianca]

http://www.islandone.org/APC/Electric/06.htm



                                 



ELECTRON-BOMBARDMENT ION ENGINE



Robert H. Frisbee


“The DC Electron-bombardment (EB) ion thruster was first operated in the laboratory in 1960 at NASA LeRC.   With high efficiency (50-75%) and high specific impulse (2,500-10,000 lbf-s/lbm, the electron-bombardment ion thruster offers significant increases in payload, and reductions in trip time and initial mass, enabling lower cost, faster planetary missions.   EB ion thrusters produce thrust by accelerating a beam of positive ions through an electrostatic field to high velocity.
Mercury vapor was used as propellant in laboratory tests for over 20 years and was successfully used in two flight experiments.   Environmental concerns regarding mercury handling resulted in mercury being replaced by xenon in ion engine development programs throughout the world.”