THE NEXT GENERATION OF SPACE EXPLORATION MISSIONS SUCH AS THE ASTEROID RETURN MISSION AND THE HUMAN EXPLORATION OF MARS ARE NOT FEASIBLE WITH THE TECHNOLOGY THAT CURRENTLY EXISTS. HIGH POWER ELECTRIC PROPULSION HAS BEEN IDENTIFIED BY THE NATIONAL RESEARCH COUNCIL NRC AS A TECHNOLOGY CAPABLE OF PROVIDING BOTH THE POWER AND EFFICIENCY REQUIRED FOR NASA'S ROBOTIC AND MANNED MISSIONS. THE HALL EFFECT THRUSTER IS AN IN-SPACE ELECTRIC PROPULSION TECHNOLOGY THAT IS CURRENTLY BEING CONSIDERED FOR NASA S ASTEROID RETRIEVAL MISSION AND FOR MANNED MISSIONS TO MARS. BY THE NRC'S RECOMMENDATION NASA SHOULD FOCUS ITS HALL THRUSTER RESEARCH INTO THREE TARGET AREAS TO ACHIEVE A TECHNOLOGY READINESS LEVEL OF 6. THE FIRST OBJECTIVE IS TO SCALE THE THRUSTERS TO PRODUCE 1 MW OF POWER. SECOND THE INTERACTION BETWEEN PLASMA PLUME AND THE REST OF THE SPACECRAFT SHOULD BE CHARACTERIZED TO IDENTIFY POTENTIALLY ADVERSE EFFECTS. FINALLY RESEARCH SHOULD CONCENTRATE ON IMPROVING THRUSTER LIFETIME AND MINIMIZING EROSION. THIS PROPOSAL AIMS TO ADDRESS THE LIFETIME AND EROSION OF HOLLOW CATHODES IN HALL THRUSTERS. IN PARTICULAR THE PROPOSED RESEARCH FOCUSES ON UNDERSTANDING THE PHYSICAL PHENOMENA WHICH DRIVE EROSION PROCESSES AND HOW THEY SCALE WITH CATHODE POWER THRUSTER POWER AND MAGNETIC FIELD TOPOLOGY. TO ACCOMPLISH THIS THE PRIMARY DIAGNOSTICS WILL BE TIME RESOLVED LASER INDUCED FLUORESCENCE (TRLIF) A RETARDED POTENTIAL ANALYZER RPA AND HIGH-SPEED DUAL LANGMUIR PROBES HDLP. TRLIF MEASURES THE VELOCITY DISTRIBUTION FUNCTION AS A FUNCTION OF TIME THE HDLP MEASURES THE PLASMA DENSITY ELECTRON TEMPERATURE AND PLASMA POTENTIAL IN THE TIME DOMAIN AND THE RPA MEASURES THE TIME AVERAGED ION ENERGY. USING THESE PLASMA DIAGNOSTICS FOUR RESEARCH PHASES ARE PROPOSED.