The title refers to the Valles Marineris (Mariner Valleys) canyon system on Mars, the largest in the Solar System. It stretches across nearly a quarter of the planet, roughly 3870 km (2400 miles) in length, spans 600 km (370 miles) at its widest and goes down 9.3 km (5.8 miles) at its deepest. The system was named after the 1971 Mariner 9 Mars orbiter.

The stardate is 2491.5, about six months after the events of SNW: “New Life and New Civilizations”. Pike says this is their 15th mission in a row. This is the first mention of Tulaxar in lore.

Pike’s affinity for horses dates back to his first appearance in TOS: “The Cage”, and he was seen riding in SNW: “Strange New Worlds” as well as keeping a saddle in his quarters (SNW: “Those Old Scientists”). Another captain who enjoys riding is TNG’s Jean-Luc Picard. The way Pike is speaking about meds and not being discovered makes me think this is an aid mission to a Prime Directive-protected planet.

Spock and La’An began a relationship in SNW: “A Space Adventure Hour”. Una is concerned that Pike is keeping busy to not think about the loss of his lover Marie Batel (“New Life and New Civilizations”).

These are the first mentions of the K’thonia disaster and the FFakisha conflict. S’Sha (as the Vulcan cadet is named in IMDB) says Uhura is “several years older” than she is, but is not clear by how much. Spock entered the Academy at age 19, and Uhura was 22 in Season 2 (“Those Old Scientists”), so I estimate her age to be about 23-24 now, making it around 2263-ish.

Pelia claims she saw a category 10 interstellar squall from inside a “phone box”, a reference to the Doctor’s space-time machine, the TARDIS, from the long-running British television series Doctor Who which is permanently stuck in the shape of a British police phone box from the 1960s. We saw the TARDIS floating in the background near a scavenger ship in SNW: “The Sehlat Who Ate Its Tail”.

Ortega’s console is showing Enterprise moving at Warp 6.25 around the storm.

Scotty says they cannot ignite the warp engines without iridium. In TOS: “Bread and Circuses”, the SS Beagle was in need of iridium after suffering unspecified damage.

The shuttlecraft is named Curie, presumably after Marie Curie, which follows the convention of naming Enterprise shuttles after scientists like Galileo (TOS: “The Galileo Seven”) or Einstein (TOS: “The Doomsday Machine”). The 24th century successor to Curie was attached to Enterprise-D (TNG: “Parallels”).

65 million years in the past would place the ship in the Cretaceous period, the last hurrah of the dinosaurs, and the period to which the Tyrannosaurus Rex belonged. One might ask where the Voth (VOY: “Distant Origin”) are, but the Doctor hypothesised that they descended from hadrosaurs that survived the extinction of the dinosaurs, which means they evolved after the end of the Cretaceous.

The episode attributes the origin of the Valles Marineris to the crash of a Dol’drm ship, the aliens being an insectoid species. The scar on the planet reminds me of what was left by the Xindi probe (ENT: “The Expanse”).

La’An carries Augment genetics as a descendant of Khan Noonien Singh (SNW: “Tomorrow and Tomorrow and Tomorrow”).

Like Archer did in ENT: “Damage” to an Illyrian ship and a warp coil during the Xindi war, the Martians steal a critical component from Enterprise in service of their war with the Dol’drms, in this case an antimatter fuel cell.

Spock finds a fifth planet between Mars and Jupiter. One of the theories about the origins of the Asteroid Belt are that it was either a planet that never quite formed or the remains of one. I guess the latter is where Star Trek is laying its hat.

The Chicxulub asteroid, named after the Chicxulub Pueblo community on the Yucatan Peninsular where its namesake crater is located, is believed to be the primary cause of the extinction of the dinosaurs. Pelia says she remembers the evolution of humanity, which is another hint to how old she actually is. While Homo sapiens arose around 300,000 years ago, the genus dates back some 2-3 million years at least.

What the crew describes at the end is a predestination paradox. We hate those (DS9: “Trials and Tribble-lations”).

A Princess of Mars is the first John Carter of Mars novel by Edgar Rice Burroughs, describing the adventures of a former Confederate soldier who is astrally transported to a populated Mars in conflict.

Pike says they created the solar storm that sent them back in time as part of the paradox, but it’s not clear how that would have happened, since the explosion that sent them back took place 65 million years in the past and in the Sol system.