1986

By 1986, International Space Command had regular lunar flights and maintained a tracking station in Antarctica. (TV: The Tenth Planet, PROSE: Mondas Passing)
 * 28 January - The space shuttle Challenger exploded. (PROSE: Return of the Living Dad, PROSE: Father Time)
 * 26 April - The nuclear power plant in Chernobyl in the Soviet Union (later the Ukraine) went into meltdown. (COMIC: Black Destiny)
 * Edward Grainger was invited to a dinner with three of his former British Intelligence colleagues. (PROSE: Old Boys)
 * Humans first detected the planet Mondas returning to the solar system. It apparently was in orbit between Mars and Venus. The manned atmospheric probe Zeus IV was destroyed by the planet's Cyberman inhabitants and they launched an attack on Earth, starting with the Snowcap base in Antarctica. They planned to use a Z-bomb located there to destroy Earth as one of the two worlds needed to be destroyed to save the other. When they failed, Mondas was destroyed instead. Present for these events was the First Doctor and while the Cybermen were defeated, the strain of the conflict led to his subsequent regeneration from his first incarnation into his second. (TV: The Tenth Planet)
 * Professor Allison Williams led the scientific team which investigated the Cyberman ship in Antarctica. (PROSE: The Power of the Daleks)
 * 31 December - Twenty years after they helped the First Doctor prevent the return of Mondas in the then-future year of 1986 in their personal timelines, Ben Jackson and Polly Wright - who had gone their separate ways in life following a brief relationship after their return to Earth on 20 July 1966 - reunited on New Year's Eve in 1986, which was by then their present. Ben believed that numerous governments may have covered up the return of Mondas and the Cybermen invasion of the Snowcap. (PROSE: Mondas Passing)

Unknown dates

 * Toshiko Sato's family moved back to the UK from Japan. (TV: Greeks Bearing Gifts)
 * Pete Tyler and Jackie Tyler married. The event was witnessed secretly by their future daughter Rose Tyler and the Ninth Doctor. (TV: Father's Day)
 * Martha Jones was born. (PROSE: Wooden Heart)
 * James Stevens' former father-in-law died. His ex-wife Natasha allowed him to see his son Will. (PROSE: Who Killed Kennedy)
 * Rose Tyler was born. (TV: The Unquiet Dead, Bad Wolf, Army of Ghosts)