Sergei Krikalev

Sergei Konstantinovich Krikalev (Russian: Сергей Константинович Крикалёв, also transliterated as Sergei Krikalyov; born 27 August 1958) is a Russian mechanical engineer and former cosmonaut and head of the Yuri Gagarin Cosmonaut Training Center.

As a prominent rocket scientist, he is a veteran of six space flights and ranks fourth to Oleg Kononenko, Gennady Padalka, and Yuri Malenchenko for the most time spent in space: a total of 803 days, 9 hours, and 39 minutes.

Krikalev was stranded on board the Mir during the dissolution of the Soviet Union. As the country that had sent him into space no longer existed, his return was delayed and he stayed in space for 311 consecutive days, twice as long as the mission had originally called for.

He retired as a cosmonaut in 2007 and was working as vice president of Space Corporation Energia. From 2009 to 2014, he headed the Yuri Gagarin Cosmonaut Training Center. Krikalev was born in Leningrad in the Soviet Union (now Saint Petersburg, Russia). He enjoyed swimming, skiing, cycling, aerobatic flying, and amateur radio operations, particularly from space (callsign U5MIR). He graduated from high school in 1975. In 1981, he received a mechanical engineering degree from the Leningrad Mechanical Institute, now called Baltic State Technical University.

After graduation in 1981, he joined NPO Energia, the Russian industrial organization responsible for crewed space flight activities. He tested space flight equipment, developed space operations methods, and participated in ground control operations. When the Salyut 7 space station failed in 1985, he worked on the rescue mission team, developing procedures for docking with the uncontrolled station and repairing the station's on-board system.