Yuri Alekseyevich Gagarin (Russian: Ю́рий Алексе́евич Гага́рин; 9 March 1934 – 27 March 1968) was a Soviet pilot and cosmonaut. He was the first human to journey into outer space when his Vostok spacecraft completed an orbit of the Earth on 12 April 1961.
Gagarin became an international celebrity and was awarded many medals and titles, including Hero of the Soviet Union, the nation's highest honour. Vostok 1 marked his only spaceflight, but he served as backup crew to the Soyuz 1 mission (which ended in a fatal crash). Gagarin later became deputy training director of the Cosmonaut Training Centre outside Moscow, which was later named after him. Gagarin died in 1968 when the MiG-15 training jet he was piloting crashed. The Fédération Aéronautique Internationale awards the Yuri A. Gagarin Gold Medal in his honor.
About that fatal crash:
A second plane being tested that day, an Su-15 jet, mistakenly flew far lower than its planned altitude of 33,000 feet, instead passing close to where Gagarin’s plane had been flying, around 2,000 feet. Such a large aircraft would be able to roll over a smaller one (like the MiG-15) in its wake if the two planes came too close to each other.
After running various computer simulations, the report concluded that the only viable explanation for the crash was that the Su-15 flew too close to Gagarin’s plane that day, flipping it and forcing it into an unrecoverable spiral dive towards the ground.
The newly declassified archival documents were released just in time for Cosmonautics Day, celebrating cosmonaut Yuri Gagarin's historic April 12, 1961 flight aboard the Vostok 1 spacecraft.
The archival release includes over a dozen pages of never-before-seen material, starting with an official accounting of Gagarin's military postings and his promotion through the ranks of the Soviet Air Force, from lieutenant in 1957 following his completion of the Chkalov Air Force Pilot's School in Orenburg, to senior lieutenant in 1959, to lieutenant-colonel in 1962 and finally colonel in 1963. The latter are accompanied by the relevant orders to confer the cosmonaut the new ranks. ...