This study examined the effects of calcium and vitamin D supplementation on bone health in mice exposed to ionizing radiation. Mice were separated into five groups: a control, radiation only, radiation with vitamin D, radiation with calcium, and radiation with both calcium and vitamin D. MicroCT scans and alkaline phosphatase tests were performed weekly for 10 weeks. Results showed the radiation-only group had the worst osteopenia and lowest alkaline phosphatase levels. The group receiving both calcium and vitamin D showed the greatest improvement in bone density and alkaline phosphatase activity, indicating increased osteoblastic activity and bone formation. The study suggests calcium and vitamin D supplementation may help counteract bone loss in astronauts exposed to radiation levels during space travel.