Grigori Kalashnikov was a Soviet astrophysicist. He was born in 1919. On 10 November 1963, as he and Christina Pushkin were headed for the Baikonur Cosmodrome in a jeep, they were both shot. Their corpses were then completely destroyed in a time-bomb explosion.
After his death, the Sixth Doctor, having taken his identification papers while inspecting their corpses, assumed Kalashnikov's identity, and took his place at the Cosmodrome in helping return Vostok 7 to Earth. (AUDIO: 1963: The Space Race)