PROPOSED HERE IS THE DEVELOPMENT AND TESTING OF A LONG LIFE HIGH-POWER HALL THRUSTER THE X3 MAGNETICALLY SHIELDED MS. THE X3 MS IS A 100KW CLASS NESTED-CHANNEL HALL THRUSTER. ITS PREDECESSOR THE X3 UNSHIELDED US WAS JOINTLY DEVELOPED BY THE PLASMADYNAMICS AND ELECTRIC PROPULSION LABORATORY PEPL AT THE UNIVERSITY OF MICHIGAN NASA AND THE AIR FORCE OFFICE OF SCIENTIFIC RESEARCH. THE X3 US IS CURRENTLY UNDERGOING A FULL PERFORMANCE CHARACTERIZATION TO GATHER THRUST DATA AND PLUME CHARACTERISTICS. THIS DATA WILL BE USED TO DEVELOP A PHYSICS MODEL OF THE THRUSTER AND INVESTIGATE THE INTERACTION BETWEEN CHANNELS IN NESTEDCHANNEL HALL THRUSTERS. ONCE COMPLETE NEW BREAKTHROUGHS IN LIFE PROLONGING TECHNOLOGIES WILL BE IMPLEMENTED ON THE X3 TO ENABLE A MINIMUM LIFETIME OF 10 000 HOURS. THE DEVELOPMENT OF THE X3 WAS A CRITICAL STEP FORWARD IN THE FIELD OF ELECTRIC PROPULSION AND IN NASA S PLAN TO LEVERAGE HIGH-POWER HALL THRUSTERS ON A VARIETY OF MISSIONS SUCH AS A MANNED MISSION TO MARS. HOWEVER THE TECHNOLOGY CANNOT CURRENTLY BE USED ON DEEP SPACE MISSIONS DUE TO LIFETIME ISSUES. EROSION IS THE MAIN MECHANISM OF FAILURE ON A HALL THRUSTER AS ONCE THE WALL THICKNESS REACHES A CRITICAL LEVEL THE MAGNETIC CIRCUIT IS EXPOSED AND SHORTED. THE DEVELOPMENT OF THE X3 MS WILL MITIGATE THIS ISSUE BY SIGNIFICANTLY REDUCING AND ULTIMATELY STOPPING THE EROSION OF THE CHANNEL. THE PROJECT INVOLVES THE DESIGN FABRICATION AND TESTING OF X3 MS. THE MAIN DESIGN CHANGES FROM X3 US ARE THE MAGNETIC FIELD AND THE CHAMFERING OF THE ISOLATION WALLS AT THRUSTER EXIT. THESE CHANGE ALLOWS FOR PLASMA POTENTIAL NEAR THE WALLS EQUAL TO THAT OF THE DISCHARGE VOLTAGE LOW ELECTRON ENERGIES NEAR THE WALL AND FIELD LINES THAT EXIT THE THRUSTER WITHOUT INTERSECTING THE WALL SUCH THAT THE IONS ARE NOT ACCELERATED INTO THE WALLS. THESE ASPECTS ARE THE MAIN REQUIREMENTS BEHIND MAGNETIC SHIELDING OF A HALL THRUSTER.