In 1969, the USS Enterprise, which had accidentally traveled back in time from the year 2267, took aboard Shaun Geoffrey Christopher's father, Captain John Christopher, when he attempted to intercept the Enterprise with his F-104 Starfighter. Initially believing that returning Christopher to Earth would be impossible, due to the fact that he might inadvertently change history with his new-found knowledge of the future, Lieutenant Commander Spock eventually realized that he had to be returned, or Shaun Geoffrey Christopher would never be born and the Saturn mission would never take place.
- Astronauts Fontana and O'Herlihy are named after writer D.C. Fontana and director Michael O'Herlihy of "Tomorrow is Yesterday".
- According to Star Trek Chronology, this mission took place in 2009. This date is based on conjecture that forty years had passed after the events of "Tomorrow is Yesterday".
- According to the Star Trek Spaceflight Chronology, this mission took place in 2020. The spaceship used on the mission was the Aventeur-class UNSS Lewis and Clark, a clean fission-powered ship assembled in Earth orbit in the year 2008. It was 125 meters in length and had the crew complement of three officers, twelve crew, and the passenger capacity of 94. The same ship was used for the first manned mission to Jupiter in 2014. The voyage to Saturn lasted 81 days. Geological surveys discovered signs of past mining on the second and fourth moons of Saturn, such as laser-cut mine shafts, tread marks, and strip mining scars. This was the first sign of the existence of intelligent extraterrestrial life. According to VOY: "One Small Step", however, no signs of intelligent extraterrestrial life had been discovered prior to 2032.
- In the novel The Rings of Time, the name of the ship as Lewis & Clark and the 2020 launch date of the Earth-Saturn probe are both used.