Donald Roy Pettit (born April 20, 1955) is an American chemical engineer and a NASA astronaut. He is a veteran of a six-month stay aboard the International Space Station and a six-week expedition to find meteorites in Antarctica.
Pettit was raised in Silverton, Oregon and is an Eagle Scout. He earned a bachelor's degree in chemical engineering from Oregon State University in 1978 and a doctoral degree from the University of Arizona in 1983. He worked as a scientist as the Los Alamos National Laboratory until 1996, when he was selected as an astronaut candidate. He is married and has two sons.
Pettit's first space mission was as a mission specialist on ISS Expedition 6 in 2002 and 2003. During his six-month stay aboard the space station, he performed two EVAs to help install external scientific equipment. Throughout his stay on the International Space Station during his free time he filmed numerous experiments he conducted on free spheres of water in an extremely-low gravity environment in a series he called "Saturday Morning Science".