He flew aboard the space shuttle Discovery in May 1999, delivering supplies to the International Space Station (ISS) in preparation for the arrival of the first resident crew. He was selected as a cosmonaut in 1987, originally to fly the Buran space shuttle. In October 2005 he was flight engineer for the Expedition 12 crew on the ISS and performed more than 30 experiments. The mission was accomplished in over 189 days, and included two space walks totalling more than 11 hours.