 On September 5, 2007, the Korean Ministry of Science and Technology selected Ko San as the primary astronaut, and Yi So-yeon as backup, following performance and other tests during their training in Russia.A change was made on March 7, 2008, when Yi was selected to train with the primary crew, and confirmed on March 10 the Ministry of Education, Science and Technology announced that Yi would replace Ko.This was after the Russian Federal Space Agency asked for a replacement, because Ko violated regulations several times at a Russian training center by removing sensitive reading materials and mailing one back to Korea.