Franklin Ramón Chang-Díaz (born April 5, 1950, San José, Costa Rica) is an American mechanical engineer, physicist, and former NASA astronaut. He is the sole founder and CEO of Ad Astra Rocket Company as well as a member of the Cummins' board of directors. He became an American citizen in 1977. He is a veteran of seven Space Shuttle missions, tying the record, as of 2021 for the most spaceflights... show more