Radiation exposure is experienced in both radiotherapy and exploratory space missions. As cancer treatments improve and astronauts aim to explore beyond low earth, radiation’s effects on bone must be clearly understood. Nine-week old female C57BL/6 mice were evaluated for cortical bone changes by mechanical testing, micro-computed tomography, quantitative histomorphometry, percent mineralization and micro-hardness indentation. Study one, Multi-Type study, mice received a 2 Gray (Gy) gamma, proton, iron and carbon whole body radiation dose and sacrificed 110 days post-exposure. Study two, High-Dose study, mice received a 7 Gy gamma radiation whole body dose and sacrificed 14 days post-exposure. Neither study revealed significant difference between irradiated nor control groups for any assay. Sublet effect between high Linear Energy Transfer (LET) and low LET radiation was observed. Lack of changes to cortical bone is particularly interesting and may indicate a unique biological microdosimetry microenvironment. This thesis specifically examines radiation effects on cortical bone.