Tryggvason worked as a meteorologist with the cloud physics group at the Atmospheric Environment Service in Toronto in 1972 and 1973. In 1974, he joined the University of Western Ontario to work as a research associate at the Boundary Layer Wind Tunnel Laboratory working on projects involving rigid and aero-elastic model studies of wind effects on structures. In 1978, he was a guest research associate at Kyoto University, Japan, followed by a similar position at James Cook University in Townsville, Australia. In late 1979, he returned to the University of Western Ontario as a lecturer in applied mathematics. In 1982, he joined the Low Speed Aerodynamics Laboratory at the National Research Council in Ottawa. He became part of the NRC team assembled to study the sinking of the Ocean Ranger oil rig in support of the Royal Commission investigation into that tragedy. He designed and led the aerodynamics tests, which established the wind loads acting on the rig. Between 1981 and 1992, he was also a part-time lecturer at the University of Ottawa and Carleton University, teaching graduate courses on structural dynamics and random vibrations.
Tryggvason was one of the six Canadian astronauts selected in December 1983. He was back-up Payload Specialist to Steven MacLean for the CANEX-2 set of experiments which flew on Mission STS-52, October 22 to November 1, 1992. He was the Project Engineer for the design of the SVS target spacecraft which was deployed during that mission. He was the principal investigator in the development of the Large Motion Isolation Mount which has flown numerous times on the NASABoeing KC-135 and DC-9 aircraft, and for the Microgravity vibration Isolation Mount which operated on the Russian Mir space station from April 1996 until January 1998, and for the MIM-2 which flew on STS-85 in August 1997. The MIM was used on the Mir to support several Canadian and US experiments in material science and fluid physics. Tryggvason served as a Payload Specialist on STS-85, a 12-day mission to study changes in the Earth's atmosphere. During the flight, his primary role was testing MIM-2 and performing fluid dynamics experiments designed to examine sensitivity to spacecraft vibrations. This work was directed at developing better understanding of the need for systems such as the MIM on the International Space Station and on the effect of vibrations on the many experiments to be performed on the ISS. The mission was accomplished in 189 Earth orbits, traveling 4.7 million miles in 284 hours and 28 minutes. In August 1998, Bjarni Tryggvason was invited by NASA to take part in their 1998 Mission Specialist Class held at the Johnson Space Center in Houston, Texas. This training consisted of two years of physical and academic training relating to future missions. This class was the first group of astronauts to be trained as both Mission Specialist for the Space Shuttle and as potential crewmembers for the ISS. He was initially assigned as a Shuttle Avionics Integration Laboratory crew representative. SAIL is used to test, check out, and verify Shuttle flight software prior to use on the shuttle. He also supported integrated simulations on the ISS Training Facility. This facility is used for ISS crew training as well as in support of training the ISS Mission Control team.
