Franklin Chang Díaz

Franklin Ramón Chang Díaz, Ph.D. (born April 5, 1950) is a Costa Rican-American mechanical engineer, physicist and former NASA astronaut. Dr. Chang Díaz became an American citizen in 1977. He is of Chinese (paternal grandfather) and Costa Rican (maternal side) descent.Dr. Chang Díaz is currently president and CEO of Ad Astra Rocket Company.He is a veteran of seven Space Shuttle missions, making him the record holder as of 2014 for the most spaceflights (a record he shares with Jerry L. Ross).