Yuri Gagarin

Yuri Gagarin was a 20th century Soviet cosmonaut who became, as far as the majority of humanity was aware, the first human being to journey into outer space circa 1960. (TV: The Seeds of Death, AUDIO: 1963: The Space Race)

In 1903, after receiving a wealth of information from the future, Grigori Rasputin foresaw, among other things, Gagarin's achievement. (AUDIO: The Wanderer)

Before travelling to the Moon aboard a Soviet lunar capsule in November 1963, the Sixth Doctor told Peri Brown that he was far more qualified for space travel than Gagarin. (AUDIO: 1963: The Space Race)

The Seventh Doctor, Ace, Markus Creevy and Lt Raina Kerenskaya saw both Gagarin and Valentina Tereshkova, the first woman in space, on a podium in Red Square, Moscow, in the Soviet Union at a ceremony marking the fiftieth anniversary of the October Revolution on 7 November 1967. (AUDIO: Thin Ice)

Behind the scenes
Gagarin appears briefly in one of the screens inside the room that houses the Monk's propaganda machine in TV: The Lie of the Land.However, no connection has been made between him and his face in universe.