Dr. Jon Clark is a six-time space shuttle crew surgeon. He has served in top roles at Johnson Space Center and is a 26-year US Navy veteran who qualified as a Naval flight officer, Naval flight surgeon, Navy diver, and Special Forces free fall parachutist. Clark's particular focus is crew survival in space and the neurological effects caused by extreme environments. He serves as space medicine advisor for the National Space Biomedical Research Institute (NSBRI) at Baylor College of Medicine as well as chief medical officer for orbital commercial space company Excalibur Almaz. Since 2009 he has been a volunteer for the pioneering "Stratos" team, responsible for protecting a man named Felix Baumgartner from the risks as he attempts a record-breaking "space diving" jump from a balloon at 120000 feet.