Sergei Konstantinovich Krikalyov (Russian: Сергей Константинович Крикалёв, born August 27, 1958) is a Russian cosmonaut and mechanical engineer. As a prominent rocket scientist, he has been veteran of six space flights and currently has spent more time in space than any other human being. He transliterates his name in English as Sergei Krikalev.
On August 16, 2005 at 1:44 a.m. EDT he passed the record of 748 days held by Sergei Avdeyev. He now has spent a total of 803 days and 9 hours and 39 minutes in space.
Krikalev was born in Leningrad (now St. Petersburg), Russia. He enjoys swimming, skiing, cycling, aerobatic flying, and amateur radio operations, particularly from space (callsigns U5MIR and X75M1K).
On February 15, 2007, Krikalev was appointed Vice President of the S.P. Korolev Rocket and Space Corporation Energia (Russian: Ракетно-космическая корпорация "Энергия" им. С.П.Королева) in charge of manned space flights.
Krikalev was dubbed by many "the last Citizen of the USSR " as in 1991–1992 he spent 311 days, 20 hours and 1 minute aboard the Mir space station while, back on Earth, the Soviet Union collapsed. A fictional account of how Krikalev may have felt about this is described in the song "Casiopea", written by Cuban songwriter Silvio Rodríguez.