Nothing is known about Vaschenko's life prior to the outbreak, other than he was a Russian cosmonaut that had been launched into space to the International Space Station some time prior to the outbreak.
When the world fell to the undead, Vaschenko was stranded in orbit on the International Space Station, where he witnessed the lights of the cities below go dark three days before his scheduled re-entry. Approximately 51 days into the apocalypse, he made radio contact with Victor Strand, and informed him that the outbreak was global and that much of humanity seemed to have been snuffed out by the infected. The two engaged in a brief, laid-back conversation, sharing a love of literature and champagne, before their radio connection was severed.
After an unknown period time, Vaschenko presumably died as he remained stranded in orbit. 
- Killed By
- Asphyxiation (Assumed)
With no hope of returning to Earth, Vashchenko eventually dies in orbit, presumably of asphyxiation. It is unknown if he reanimated.
- "Children of Wrath" (Voice Only)
- Vaschenko is the first known character in the entire The Walking Dead universe to reside in outer space.
- He is also the first Russian character in the Television timeline.
- Before being contacted by Victor, Vaschenko is singing The Cyan Blue Express from the Russian cartoon "Cheburashka".
- Since Vashchenko was isolated from the rest of humanity when the outbreak began, it's unknown whether he reanimated after he died let alone if he's even able to.
- Dave Erickson, July 2017, http://www.hollywoodreporter.com/live-feed/fear-walking-dead-midseason-finale-explained-1019455