STS-89

STS-89 was the eighth of nine planned missions to Mir and the fifth involving an exchange of U.S. astronauts. Astronaut David Wolf, who had been on Mir since late September 1997, was replaced by Astronaut Andrew Thomas. Thomas spent approximately 4 months on the orbiting Russian facility before returning to Earth when Discovery docked to Mir in late May during STS-91. During the mission, more than 3,175 kilograms (7,000 lb) of experiments, supplies and hardware were transferred between the two spacecraft.