THE EFFECT OF TERRAIN STRENGTH AND LAYERING ON DETERMINING CRATER-RETENTION AGES OF LUNAR SURFACESTHE OBJECTIVES OF THE PROPOSED WORK ARE TO ASCERTAIN THE INFLUENCE THAT REGIONAL AND VERTICAL VARIATIONS OF TERRAIN MECHANICAL PROPERTIES HAVE ON CRATER SIZE-FREQUENCY DISTRIBUTIONS (SFDS) AND ON COMPUTING CRATER-RETENTION AGES OF LUNAR SURFACES. ANALYZING CRATER SFDS AND USING THEM TO DETERMINE MODEL AGES OF SURFACES IS AN IMPORTANT TECHNIQUE IN UNDERSTANDING THE MOON'S GEOLOGIC HISTORY AND EVOLUTION. FURTHERMORE OUR MOON HAS BEEN THE PRIME PLACE TO DEVELOP THE CHRONOLOGIES USED FOR COMPUTING CRATERRETENTION AGES THROUGHOUT THE INNER SOLAR SYSTEM. HOWEVER ALTHOUGH THE EFFECTS OF TERRAIN MECHANICAL PROPERTIES ON CRATERING WAS RECOGNIZED SINCE LUNAR ORBITER IMAGING IMPLICATIONS FOR THE DEVELOPMENT AND USE OF LUNAR CRATER CHRONOLOGIES HAS SO FAR BEEN NEGLECTED. CRATER SFDS VARY IN SHAPE DEPENDING ON THE PROPERTIES OF THE TERRAINS ON WHICH THEY ARE RECORDED. THEREFORE WE CAN LEARN ABOUT THE EFFECTS OF TERRAIN PROPERTIES THROUGH FITTING OBSERVED CRATER SFDS WITH CRATER PRODUCTION FUNCTIONS GENERATED BY CONVERTING IMPACTOR FLUXES USING CRATER SCALING LAWS (E.G. THE MODEL PRODUCTION FUNCTION MPF). THE TASKS PROPOSED HERE TO ACHIEVE OUR OBJECTIVES WILL FIRST COMPILE CUMULATIVE CRATER SFDS FOR DOZENS OF TERRAINS WITH BROADLY DIFFERENT PROPERTIES (E.G. MARE VS. HIGHLANDS) ACROSS THE LUNAR SURFACE. WE WILL MEASURE CRATER DIAMETERS WITHIN THE RANGE ~10 M TO ~20 KM ON BOTH THE LUNAR RECONNAISSANCE ORBITER (LRO) WIDE ANGLE CAMERA GLOBAL MOSAIC (100 M/PIXEL) AND NARROW ANGLE CAMERA IMAGES (0.5-2 M/PIXEL) AVAILABLE CURRENTLY THROUGH THE PDS. BASIC GEOLOGICAL MAPS WILL ALSO BE GENERATED FOR EACH REGION TO PROVIDE CONTEXT FOR THE ANALYSIS OF THE CRATER SFDS. THEN IN THE SECOND TASK THE OBSERVED CRATER SFDS WILL BE FIT WITH SEVERAL VERSIONS OF THE MPF USING A VARIETY OF CRATER SCALING LAWS WHICH INCORPORATE DIFFERENT TERRAIN PROPERTIES. HERE WE WILL CONSIDER A RANGE FOR EACH CASE TAILORED USING OUR GEOLOGICAL MAPPING (E.G. MARE IS LIKELY TO BE MORE COMPETENT THAN HIGHLANDS). THIS WILL INFORM HOW TERRAIN PROPERTIES INFLUENCE THE CRATER SFDS AND THE MODEL AGES COMPUTED FOR THAT REGION. FURTHERMORE TO DERIVE NEW SCALING LAWS FOR LAYERED TERRAINS WE WILL USE CONSTRAINTS PROVIDED BY THE CRATER SFDS AND MPF FITS ALONG WITH HYDROCODE MODELING OF CRATER FORMATION IN A TERRAIN WITH VERTICAL VARIATION IN MECHANICAL PROPERTIES. RESULTS FROM THE PROPOSED WORK WILL CONSIDERABLY ENHANCE UNDERSTANDING OF HOW TERRAIN PROPERTIES AFFECT LUNAR CRATER SFDS AND COMPUTATION OF CRATER-RETENTION AGES OF LUNAR SURFACES. THESE IMPROVEMENTS WILL FURTHER RESULT IN BETTER INTERPRETATIONS OF THE GEOLOGICAL HISTORY AND EVOLUTION OF THE MOON (AND BEYOND). THE WORK IS RELEVANT TO LUNAR DATA ANALYSIS PROGRAM BECAUSE: 1) IT WILL ENHANCE SCIENTIFIC RETURN OF THE LRO MISSION BY BOTH USING IMAGES FOR THIS ANALYSIS AND IMPROVING FUTURE INTERPRETATIONS OF DATA FROM ANY IMAGE AND 2) IMPROVING UNDERSTANDING OF THE EVOLUTION OF THE LUNAR SURFACE.