Colonel Shaun Geoffrey Christopher, first name sometimes rendered as Sean, was a male human who lived on Earth during the 20th and 21st centuries. He was the son of United States Air Force officer Captain John Christopher. He was an astronaut and founding member of the 21st century Earth Starfleet.
In the 1990s, Christopher was selected to pilot the top secret DY-100 prototype, working with people such as Doctor Walter Nichols, Jackson Roykirk and Shannon O'Donnell. However, the DY-100 prototype was launched into orbit on January 5, 1996, before Christopher had an opportunity to pilot the ship. Afterwards, Christopher tried to comfort O'Donnell when she was dismissed from her position. (TOS novel: The Rise and Fall of Khan Noonien Singh, Volume 2)
On September 11, 2001, Christopher was prevented from boarding a commercial flight by Gary Seven. This turned out to be very fortunate for Christopher when the flight he was going to board was hijacked and used in the September 11th terrorist attacks. (ST short story: "Assignment: One")
In the early 21st century, upon the founding of a new space organization called Starfleet, he gained the rank of commander and was assigned to orient the first class of cadets at the new Starfleet Academy. During the orientation, however, a timeship from the future appeared, containing Voula, a Vulcan starfleet officer from the future. She warned him of an impending attempt to change history by a Romulan named Simeon. The two had to work together to defeat the Romulans and preserve history. They did so by beaming aboard the Romulan ship with a host of tribbles. (ST performance: Star Trek Live)
- This 21st century Starfleet, of which Christopher was a member, is likely to be a predecessor of the United Earth Starfleet, itself a predecessor to the Federation Starfleet. It operates well before the founding of United Earth, coordinating with NASA.
In 2020, Christopher commanded the UNSS Lewis and Clark on the first manned mission to Saturn. He was joined on that historic mission by Alice Fontana and Dr. Marcus O'Herlihy. Soon after the ship launched, however, it was discovered that a stowaway was aboard, a blogger by the name of Zoe Querez. Christopher recommended to NASA that the mission not be scrubbed despite the unwanted company, fearing that it could destroy their chances of trying again for the Saturn mission. And so she became informally a member of the ship's crew.
When the ship arrived at Saturn, it was discovered that the rings were destabilizing and that the hexagonal vortex at the planet's core was shrinking. A Preserver probe, disguised as an icy comet, had arrived to repair the artificial gravity system inside Saturn to restore the rings. When the crew of the Lewis & Clark saw this alien probe, Christopher ordered that they pursue it towards the planet. He then left the ship on a space walk to bring the probe in for study. He witnessed it discharge at the surface, before touching the probe's hull. Instantly, his consciousness was switched with that of Captain James T. Kirk in the 23rd Century, who had also touched the probe in that era.
In Kirk's body, Christopher was confined to sickbay until Spock performed a mind meld on him to ascertain his identity. After that, he was confined to sickbay to prevent him gaining knowledge of the future, which would contaminate the timeline. However, he escaped from confinement after the ship he was on, the USS Enterprise, was hit by a large asteroid and made his way to the bridge. This was in the middle of a crisis, as the Klondike VI colony was about to plummet into the planet's atmosphere due to its destabilized orbit. Spock ordered Christopher off the bridge, but Qat Zaldana recommended that he remain, explaining the situation to him. Comparing Klondike VI's current state with what he had witnessed on Saturn, Christopher realized that he remembered the rhythm by which the alien probe had sent pulses to Saturn in his time. Spock agreed to let him try firing the Enterprise's phasers into the hexagonal storm at Klondike VI's pole, in the hope that they were similar enough to the energy fired by the probe to have the same effect. This worked, restoring the artificial gravity and saving the colony. The Enterprise then traveled back in time to 2020, where they beamed Christopher's body, which was inhabited by Captain Kirk, aboard and Spock was able to transfer their intelligences back to their respective bodies. Christopher was then returned to the Lewis & Clark, where he began a romance with Alice Fontana. (TOS novel: The Rings of Time)
- The Last Unicorn Games RPG book All Our Yesterdays: The Time Travel Sourcebook gives the Christopher Saturn mission's date as 2009.
In 2021, he married Alice Fontana, following their historic mission together aboard the USS Lewis & Clark. They had two children, the eldest being a son whom they named James Kirk Christopher-Fontana. (TOS novel: The Rings of Time)
Years prior to his Saturn mission, Christopher had a relationship with Debbie Lauderdale, which produced three children: Katie and Kevin, who were both college age as of 2020, and Rory, who was 8 years old in that year. However, the relationship with Debbie was fully over by then, and when he returned from the Saturn mission, he had a fourth child with Alice Fontana. (TOS novel: The Rings of Time)
In an alternate timeline in which Khan Noonien Singh was victorious in the Eugenics Wars, Christopher, Shannon O'Donnell, Rain Robinson and about 100 of Earth's top scientific minds launched the SS Botany Bay in November 2010. Their intention was to escape the horrors of Khan's conquests and settle on a habitable planet in the Eta Cassiopeiae star system. Unfortunately, the ship went off course and was eventually discovered in June 2376 by Princeps Julian Bashir of the Khanate of Earth starship Defiance. Christopher and the rest of the crew of the Botany Bay learned that Khan had forced Earth's entire population to undergo genetic engineering and had gone on to create a brutal and despotic interstellar empire known as the Khanate of Earth. (Myriad Universes novel: Seeds of Dissent)