He received a bachelor of engineering degree in mechanical engineering, with First Class Honors, from the University of Adelaide in 1973, and a doctorate in mechanical engineering from the University of Adelaide in 1978.
In August 1993, following one year of training, he was appointed a member of the astronaut corp and was qualified for assignment as a mission specialist on Space Shuttle flight crews.
In June 1995 Dr. Thomas was named as payload commander for STS-77 and flew his first flight in space on Endeavour in May 1996. He next trained at the Gagarin Cosmonaut Training Center in Star City, Russia in preparation for a long-duration flight. In 1998, he served as Board Engineer 2 aboard the Russian Space Station Mir for 130 days. Dr. Thomas completed his third space flight on STS-102 and has logged over 163 days in space.
Dr. Thomas currently serves as Deputy Chief of NASA's Astronaut Office.