Franklin Ramón Chang Díaz (born April 5, 1950) is a Costa Rican-American engineer, physicist and former NASA astronaut. He 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 2008 for the most spaceflights (a record he shares with Jerry L. Ross). He was one of the first Hispanic or Latino Americans to go into space, and is the first naturalized US citizen to become an astronaut.
Chang-Diaz was born in San José, Costa Rica to a father of Chinese descent and a Spanish Costa Rican mother, both Costa Rican-born. He studied at La Salle School, then moved to the United States to finish his high school education. He earned a B.S. degree in mechanical engineering from the University of Connecticut (where he joined the federal TRIO Student Support Services program) in 1973, and a Sc.D. degree in applied plasma physics from the Massachusetts Institute of Technology (MIT) in 1977. For his graduate research at MIT, Chang-Diaz worked in the field of fusion technology and plasma-based rocket propulsion.
Chang-Diaz was selected as an astronaut candidate by NASA in 1980 and first flew aboard STS-61-C in