WE PROPOSE TO EXAMINE FRESH IMPACT CRATERS OF SIMILAR SIZE WITH DIFFERENT MORPHOLOGIES IN ORDER TO ENHANCE KNOWLEDGE OF IMPACT CRATERING MECHANICS AND THE NEAR-SURFACE RHEOLOGY OF THE MARTIAN CRUST. TO MAXIMIZE VARIATION IN MORPHOLOGY WE WILL LOOK AT CRATERS WITH DIAMETERS OF SEVEN TO NINE KILOMETERS WHICH IS WITHIN THE GLOBAL RANGE FOR THE TRANSITION FROM SIMPLE TO COMPLEX CRATERS. EXAMINING CRATERS OF SIMILAR DIAMETER EFFECTIVELY HOLDS ONE PARAMETER IMPACT ENERGY CONSTANT. OUR GOALS ARE TO IDENTIFY THE TARGET PROPERTIES RESPONSIBLE FOR THE OBSERVED MORPHOLOGICAL VARIATIONS AND UNDERSTAND HOW THOSE PROPERTIES ALTER THE CRATERING PROCESS. IN OUR FIRST TASK WE WILL LOOK AT THE GLOBAL COLLECTION OF WELL-PRESERVED CRATERS IN THIS DIAMETER RANGE AND ASSESS HOW MORPHOLOGY VARIES WITH GEOLOGIC SETTING. WE WILL DEVELOP HYPOTHESES REGARDING HOW DIFFERENT TARGET PROPERTIES AFFECT THE CRATERING PROCESS. WE WILL EVALUATE THESE HYPOTHESES BY SELECTING TYPE EXAMPLES AND FURTHER EXAMINING THESE CRATERS WITH STEREO-DERIVED DIGITAL ELEVATION MODELS AND HIGH RESOLUTION IMAGES. THE WORK INVOLVES DETAILED GEOLOGIC ANALYSIS USING A VARIETY OF IMAGING AND TOPOGRAPHIC DATA SETS FROM RECENT MARS MISSIONS CONSISTENT WITH THE MDAP PROGRAM. IMPACT CRATERING IS THE MOST COMMON GEOLOGIC PROCESS IN THE SOLAR SYSTEM AND THE PROPOSED EFFORT WILL ADVANCE KEY ASPECTS OF OUR UNDERSTANDING OF THE IMPACT PROCESS. THIS WORK WILL ALSO IMPROVE OUR ABILITY TO USE IMPACT CRATERS TO INFER PLANETARY NEAR-SURFACE CRUSTAL PROPERTIES. THIS PROPOSAL SUPPORTS NASA'S STATED SUBGOAL TO ADVANCE SCIENTIFIC KNOWLEDGE OF THE SOLAR SYSTEM.