Experimental investigation of carbon contamination inside discharge chamber of ion thruster

Contamination taking place in a discharge chamber of an ion thruster was in vestigated using carbon-carbon composite grids. The contamination was cause d by the grid materials that were damaged and eroded by the ion sputtering. The contaminant has the possibility to cause a short circuit between the e lectrodes, resulting in a total loss of the ion thruster. We have investiga ted the property of the carbon contamination with respect to its size and s hape experimentally. For prevention of such an accident, the statistical fe atures of the carbon contamination were evaluated and a method to eliminate the contaminant was demonstrated.