Dr. Thirsk is one of the six original Canadian astronauts selected in December 1983. He began astronaut training in February 1984, and served as backup payload specialist to Marc Garneau for space shuttle mission 41-G which flew in October 1984. Bob has participated in parabolic flight experiments aboard NASA aircraft, and has contributed to Canadian Space Agency (CSA) projects in space medicine as well as space station and shuttle mission planning. He led an international research team investigating the effect of weightlessness on the heart and blood vessels. Bob served as Chief Astronaut of the CSA in 1993 and 1994, and was crew commander for the CAPSULS mission, a simulated 7-day mission with Canadian astronauts and international science teams.
In June 1996, Bob flew as a payload specialist aboard space shuttle mission STS-78, the Life and Microgravity spacelab (LMS) mission. During this 17 day mission aboard Space Shuttle Columbia, he and his six crewmates performed 43 international experiments devoted to the study of life and materials sciences. In 1998, the CSA assigned him to the NASA Johnson Space Center in Houston, Texas, where he trained on both shuttle and space station systems and is now qualified as a mission specialist.
Dr. Thirsk currently serves as CAPCOM (capsule communicator) for the International Space Station (ISS) program at the Johnson Space Center. In this capacity, he relays voice calls and other communications between flight controllers at Mission Control and the ISS crew during spaceflights and mission simulations.
In addition, Bob has led space education projects designed to foster enthusiasm for science and mathematics among elementary school students in Canada. His work with such projects as Tomatosphere and Canoloab, which focused on growing tomato and caola plants from space flown seeds, has reached thousands of classrooms across the country. Today, he continues to participate in the development of curriculum projects, such as Space for Species, a program designed to allow Canadian students to monitor the movements and habitats of various migratory animals.