NASA astronaut Mark Vande Hei is pictured on May 4, 2021, working on Celestial Immunity, an investigation of how gravity affects the immune response, potentially supporting the development of new vaccines and drugs to prevent and treat existing and emerging human diseases. This research builds on earlier space station studies that evaluated the function of white blood cells, extending the observation period from hours to days and expanding the analysis to an array of activated immune pathways. Results could support development of new vaccines and drugs to prevent and treat existing and emerging human diseases. NASA/UPI