The proposed tasks focus on analyses of Hayabusa mission samples in order to unravel the complexities of space weathering effects preserved in Hayabusa grains and to investigate the origin and evolution of the regolith. Mineralogical and isotopic analyses of the particles will help define the shock, thermal and irradiation history of Itokawa during regolith formation and evolution. The proposed research will provide quantitative data to determine the nature of space weathering effects in Itokawa materials. Analysis and calibration of solar flare particle track densities will allow for constraints to be placed on the timing and rates of space weathering on Itokawa. We will evaluate the contributions of solar wind implantation effects and micrometeorite impact processes to asteroidal space weathering. These tasks involve coordinated analyses including nanometer-scale chemical mapping and microstructural studies of space-weathered surfaces using transmission electron microscopy and innovative focused ion beam techniques to prepare samples.