Yuri Gagarin was the first man in space when he entered Earth's orbit on 12 April 1961.
Yuri is part of the Russian group of The Manhattan Projects. He works alongside Laika, with whom he is very close (he has promised he will walk the sands of Mars with her). Despite all claims and inventions to the contrary, Yuri insists that he was still the first man in space.
He is not portrayed as particularly bright, but he is extremely brave, and considered a true hero by the rest of the group. Yuri claims that since he is an explorer, and death is the final frontier, he has nothing to be afraid of.