Astronauts in space undergo accelerated bone loss due to weightlessness, causing early onset osteoporosis and increasing fracture risk. While astronauts adhere to long and rigorous exercise regimens, a “more is better” approach to increase daily exercise may prove challenging for long missions (>1yr), necessitating the identification of combinatory therapies that would improve the salutary outcomes of exercise. As an alternative to exercise, low magnitude high frequency (LMHF) mechanical loading is a treatment often used for patients with osteoporosis. Our group has previously demonstrated LMHF vibrations increases the proliferation and osteogenesis of bone making Mesenchymal Stem Cells (MSCs). To test the effects of microgravity in MSCs we have built a simulated microgravity (sMG) system. After three days, sMG decreased cell proliferation by 63.5 % (p