NASA seeks high resolution technologies that can distinguish trabecular thickness and spacing for sites of the central skeleton to evaluate the temporal changes in cancellous bone microarchitecture due to mechanical unloading and loading - such as i) with the spaceflight analog (bed rest model), ii) with varying durations of spaceflight, iii) with return to 1G and iv) with exercise rehabilitation. Quantitative Computed Tomography [QCT] hip scans of ISS crewmembers reveal that the cortical bone volumetric Bone Mineral Density [vBMD] of the femoral neck and of the proximal femur are significantly reduced during spaceflight with a greater percentage of vBMD lost in cancellous vs. cortical bone compartment. Further evidence indicates that vBMD of cancellous bone in the femoral neck does not recover in crewmembers in the 2-4 years after return from flight. It is reported that, in vertebral bodies, the loss of trabecular connectivity and the perforation of trabeculae within cancellous bone is associated with reduced whole bone strength and fracture. However, QCT notably does not have the resolution to evaluate how the microarchitecture of cancellous bone is disrupted with the increased bone resorption that occurs in space.