- In the Star Trek Spaceflight Chronology and the TOS novel: The Rings of Time, the expedition would be aboard the Lewis and Clark. Other continuities would name the vessel differently. As well, the expedition date would be 2005, 2018 or 2020.
Christopher had at least one son, John Christopher II. (Star Trek: Refuge)
A class of small battleships, the Christophers, in service during the Earth-Romulan War was named after Christopher (TOS novel: Starfleet: Year One), as was the Gagarin-class USS Christopher of the 2180s. (The Starfleet Museum)