Abstract In response to the National Institutes of Health (NIH), -Center for the Advancement of Science in Space (CASIS), -Request for Application (RFA), -Targeted Research (TR), -16-019 we propose to apply the Organ- Chip technology of Emulate Inc., to assess the effects of space flight in human organs in vitro. Emulate is a newly founded start-up based on technology developed at the Wyss Institute at Harvard University in Cambridge, Massachusetts. The proposed work focuses on the development of automated hardware for space to enable experiments in human, in vivo relevant microphysiological systems for understanding of the impact of microgravity and other space flight-imposed stressors on human physiology, disease development and response to drugs. The organ we will apply to all proposed studies is the blood-brain barrier (BBB)-Chip, both in normal and inflamed states, which causes a major compromise in the BBB and allows for evaluation of clinically relevant endpoints. In this proposal, we will first validate Emulate?s Organ-Chip technology, and the automated instrumentation to be developed together with implementation partners SpaceTango, in terrestrial experiments simulating the space flight protocols. Next, we will use the platform to conduct two separate organ-chip experiments on the International Space Station (ISS) to understand the effects of this unique environment on BBB physiology. Further, terrestrial experiments will assess the specific contribution of each of the individual, primary cell stressors in space that can be simulated on Earth. Imaging, biochemical, and transcriptomic data from all studies over different time points will be analyzed, compared and provide the inputs for building a model of the system. We believe that our integrative approach will reveal new aspects of the effects of microgravity on the BBB in normal and disease states, and provide insights into drug discovery for this critical organ that maintains homeostasis or propagates a number of serious diseases. Successful implementation of our space compatible hardware and our BBB-Chip findings will provide an in vivo relevant, in vitro platform available to the scientific community for the evaluation of the impact of microgravity in physiology and disease of a number of human organs, and support drug development in novel, clinically relevant ways.