DIURNAL THERMAL CYCLING PLAYS AN IMPORTANT ROLE IN THE SURFACE AND ORBITAL EVOLUTION OF AIRLESS BODIES. THERMALLY INDUCED CRACK PROPAGATION CAUSES ROCK BREAKDOWN AND REGOLITH PRODUCTION THE NATURE OF WHICH AFFECTS THE DISTRIBUTION OF MATERIAL AND THE THERMAL BEHAVIOR OF THE LANDSCAPE. IN THE PROPOSED WORK I WILL INVESTIGATE THE EFFECT OF THERMAL CYCLING AT GRAIN BOULDER AND LANDSCAPE SCALES ON (101955) BENNU THROUGH TWO TASKS: 1) RECENT WORK HAS SHOWN THAT DIURNAL THERMAL CYCLING INDUCES SPATIOTEMPORALLY COMPLEX STRESS FIELDS AT THE SURFACES AND INTERIORS OF BOULDERS ON AIRLESS BODIES WHICH WORK TOGETHER TO WEAKEN THEIR OUTER LAYERS AND CAUSE NEARSURFACE DISAGGREGATION. HOWEVER CRACK PROPAGATION RATES AND STRESS THRESHOLDS ARE NOT WELL CONSTRAINED IN VACUUM ENVIRONMENTS AND THUS BREAKDOWN RATES DUE TO THIS PROCESS ARE UNKNOWN. I WILL PERFORM 3D SIMULATIONS OF BOULDERS AND LANDFORMS AT THE SURFACE OF BENNU AND QUANTIFY THEIR TEMPERATURE AND STRESS FIELDS. USING IMAGES CAPTURED BY OSIRIS-REX I WILL RELATE THE RESULTS TO THE SIZE AND MORPHOLOGY OF OBSERVED BOULDERS ROCK FRAGMENTS AND LANDSCAPE FEATURES ALLOWING ME TO CONSTRAIN STRESS THRESHOLDS AND PROVIDING INSIGHT INTO THE NATURE OF BREAKDOWN. THESE SIMULATIONS WILL ALSO REVEAL THE THERMAL INTERACTION BETWEEN BOULDERS AND SURROUNDING TOPOGRAPHY ALLOWING ME TO EXPLORE THE INTERPLAY BETWEEN BOULDER BREAKDOWN AND THE EVOLUTION OF BENNU#S THERMAL INERTIA. I WILL ALSO USE THE BOULDER SIZE-FREQUENCY DATA COLLECTED DURING THE MISSION TO CONSTRAIN CRACK PROPAGATION AND BREAKDOWN RATES. 2) AT THE GRAIN SCALE MINERAL HETEROGENEITY PLAYS AN IMPORTANT ROLE IN BOTH NEAR-SURFACE DISAGGREGATION AND GRANULAR DISINTEGRATION OF MATERIAL.