Scott Kelly spent a year in the International Space Station while his identical twin Mark Kelly was on earth. UC San Diego and many institutions studied the mental, cardiovascular, immune, genetic, muscular, microbial, bone, and eye changes in both twins to see the effects of long-term space travel. Changes were troubling, so NASA plans several more long-term space flights that will focus on genetic changes, bone loss, loss of vision, brain swelling, and Nutrition. Michael G. Ziegler, MD, is Professor of Medicine Emeritus at UCSD. He has studied astronaut health since 1978. He chaired NASA's yearly cardiovascular reviews, helped devise current astronaut protocols, and studied physiologic and genomic changes during the Year in Space study.