Yuri Kerenski

Yuri Kerenski, born in 2032, was a Russian nurse and part of the Bowie Base One Mars colony. He was a known joker, using a spare solar panel to make a "No Trespassers" sign outside the base. He had a brother, Mikhail, who lived with his husband, George, in Dagestan.

He initially had a low-level research position in the Russian Federal Space Agency and trained as a nurse in order to progress. He ended up earning the favour of the Director General after treating him, and was given a higher nursing position. This led to him training at the Johnson Space Centre and befriending Tarak Ital; Yuri stayed in the US, and Ital recommended him for the Bowie Base mission.

Yuri looked after a quarantined Maggie Cain after she was infected by Andy Stone. He was destined to die in an explosion of Bowie Base One, however he escaped along with Mia Bennett and Adelaide Brooke when the Tenth Doctor interfered with the course of events and rescued them. In the timeline where he did die, he was posthumously awarded the Hero of Russia title. (DW: The Waters of Mars)

Behind the scenes

 * "Yuri Kerenski" is an amalgamation of "Alexander Kerensky"(prime minister of Russia's provisional government) and "Yuri Gagarin"(first man in space).
 * The details of his pre-Bowie Base career can be briefly seen in his obituary.
 * In a deleted scene it was revealed he and Mia were in a relationship and kept it secret as Adelaide wouldn't allow romantic relationships. When the Doctor exposed it, the crew revealed they knew all along including Adelaide who chose to ignore it but was forced to take action to keep the two apart after it was exposed.But even though his storyline wasn't introduced the writers still seemed to keep some sort of relationship ,that none of the other crew had, between them both.
 * In another deleted scene, he did not understand why the Doctor was unaware of the Carbon Wash, which the Doctor mistook for snow. He later stopped seemingly to speak to the Doctor whilst following Mia, but was put off by the Doctor glaring menacingly at him. This clearly scared him and caused him to continue his departure.