INVESTIGATIONS OF MERCURY'S ICE-BEARING POLAR CRATERS ..THE PROPOSED WORK WOULD USE DATA IN THE PDS ARCHIVE FROM THE DISCOVERY-CLASS MESSENGER MISSION TO INVESTIGATE MERCURY'S POLAR DEPOSITS. IN PARTICULAR RAW DATA FROM THE MDIS AND MLA INSTRUMENTS AS WELL AS MESSENGER ADVANCED DEM AND GLOBAL MOSAIC PRODUCTS WOULD BE USED TO PRODUCE NEW DEMS TO MODEL THE ILLUMINATION AND THERMAL CONDITIONS OF THE DEPOSITS WITH COMPARISONS TO MAPPING AND ANALYSIS OF THE VISIBLE IMAGES OF THE DEPOSITS. THUS THE PROPOSED WORK IS HIGHLY RELEVANT TO THE OBJECTIVE OF THE DISCOVERY DATA ANALYSIS PROGRAM TO ENHANCE THE SCIENTIFIC RETURN OF DISCOVERY PROGRAM MISSIONS...THE OUTSTANDING SCIENCE QUESTION THAT MOTIVATES THE PROPOSED WORK IS: WHAT IS THE SOURCE AND EVOLUTION OF THE WATER ICE AND OTHER VOLATILES IN MERCURY'S POLAR DEPOSITS? COMPLETION OF THE FOUR INDEPENDENT TASKS PROPOSED WILL PROVIDE SIGNIFICANT NEW RESULTS THAT WILL HAVE AN IMPORTANT IMPACT ON ADDRESSING THAT FUNDAMENTAL QUESTION. THE FOUR PROPOSED TASKS ARE:. TASK #1. INVESTIGATE POLAR DEPOSITS WITH LOW-REFLECTANCE SURFACES . TASK #2. INVESTIGATE POLAR DEPOSITS WITH SURFACE ICE. TASK #3. INVESTIGATE THE LOWEST-LATITUDE CRATERS THAT HOST RADAR-BRIGHT DEPOSITS. TASK #4. INVESTIGATE THE THERMAL ENVIRONMENT OF MERCURY'S SOUTH POLAR DEPOSITS..THE COMPLETION OF THESE FOUR TASKS WILL PROVIDE RESULTS TO CONSTRAIN: 1) THE DISTRIBUTION OF MERCURY'S WATER ICE DEPOSITS 2) THE PROPERTIES OF THE LOW-REFLECTANCE MATERIALS THAT COVER THE WATER ICE IN MANY LOCATIONS AND 3) THE BOUNDARIES OF THE DEPOSITS. THE COMPLETION OF THESE FOUR TASKS WILL ADVANCE OUR KNOWLEDGE ABOUT MERCURY'S POLAR DEPOSITS AND PROVIDE NEW CONSTRAINTS THAT ANY HYPOTHESIS FOR THE SOURCE AND EVOLUTION OF MERCURY'S WATER ICE MUST MEET. .