Seth MacFarlane's sci-fi comedy-drama The Orville has tackled various sci-fi concepts across its three seasons, and alternate timelines are no exception. As with its forerunner Star Trek, MacFarlane's show tackles real-world issues through sci-fi allegory, with a real focus on the ensemble cast and the emotional lives of their characters. It's often small character decisions, rather than catastrophic events, that create the alternate timelines in The Orville.
For example, in The Orville season 3, episode 6, "Twice In A Lifetime", an accident with a temporal device sends Gordon Malloy (Scott Grimes) back in time, creating an aborted timeline where he lived as a flight engineer. In a dark spin on Star Trek: The Next Generation's controversial Geordi story where he fell in love with a simulation of scientist Leah Brahms, Gordon used his future knowledge to court, and subsequently marry the woman of his dreams. The Orville crew averted this timeline by going further back in time and rescuing Gordon before his abandonment and loneliness drove him to break the laws of time. However, this isn't the only time that The Orville explored the consequences of time travel and the alternate timelines it can create.
There are two alternate timelines from the prime Orville timeline and, oddly, both of them revolve around the love life of the Orville's captain Ed Mercer (Seth MacFarlane). One of the divergent timelines is a possible future that provides Ed with a potential love interest in the form of Pria, played by Charlize Theron. The other timeline, which forms The Orville's season 2 finale, explores what would have happened if Ed had not got together with his wife and future second-in-command, Kelly Grayson (Adrianne Palicki). As such, there are plenty of things that happen differently in The Orville's three different timelines.
The Orville's Main Timeline
For audiences, the prime Orville timeline and universe begins with the breakdown of Ed and Kelly's marriage, when he discovers her affair with Darulio (Rob Lowe) in the fall of 2418. A year later, Ed assumes command of the Union vessel the Orville, and the adventures of him and his crew begin properly. The timeline of the first three seasons of The Orville covers a similar three-year period, from the battle with the Krill on Epsilon 2 in 2419, to the wedding of Claire and Isaac in 2422. As the future of The Orville is currently unknown, it's unclear how much longer their adventures will continue.
In terms of the wider Orville timeline and universe, the details are slightly hazier. As The Orville season 1, episode 1 "Old Wounds" aired toward the end of 2017, the show takes place just over 400 years in the future. From references to Seinfeld, the Kermit the Frog toy that sits on Ed's desk, and the multicultural, multi-species Broadway production of Annie, it can be discerned that the Planetary Union's cultural history is very similar to that of contemporary society. Unlike Star Trek, however, it's not yet been made clear what the event was that inspired their more egalitarian society.
In The Orville season 3 ending, Kelly informs a visiting alien from a more primitive, 21st-century-style civilization that money "became obsolete with the invention of matter synthesis." It's wise of the show to keep its own historical timeline intentionally vague, however, as the political allegories can be much more effective if the Union's past is reflective of the audience's present-day. A present-day that the Orville's crew regularly refer to as "dark times". The Orville season 3 finale roughly dates the beginning of humanity's exploration of the stars to some time prior to 2235, when early Union explorers made a fatal error on the planet of Gendel 3.
The Orville's Pria Timeline
The Orville season 1, episode 5, "Pria", directed by Star Trek actor Jonathan Frakes, sees the crew rescue a miner called Pria, who is dangerously adrift in the gravitational pull of a star. Ed quickly begins to fall for Pria, drawing the suspicions of ex-wife Kelly, who covertly investigate the new passenger's quarters. It's revealed that Pria isn't a 25th-century miner and is instead a 29th-century antique dealer who has her eyes on the Orville, which she plans to hijack and sell to the highest 29th-century bidder.
Pria is unmasked as a nefarious time traveler after she's already saved the Orville from a devastating dark matter storm. She tells Ed that the ship was supposed to be destroyed in that same dark matter storm in December 2419, making it the perfect cover for her to remove the ship from time. Pria's plot is foiled when, after being thrown in the Orville brig by Halston Sage's Kitan, Ed orders the destruction of the wormhole that connects the 25th century with the 29th, potentially creating a new The Orville timeline in the process.
The Orville's The Road Not Taken Timeline
The Orville season 2, episode 13, "Tomorrow, and Tomorrow, and Tomorrow" sets up a dystopian Orville timeline where the Union lost their battle against the Kaylon. When an experiment with temporal technology goes wrong, a younger version of Kelly is brought aboard the Orville. This version of Kelly is from 2413 and hasn't yet agreed to go on a second date with Ed, but after seeing how their relationship plays out and experiencing a failed memory wipe, she decides to decline when she's sent back to her own time.
The ripple effect of this leads to the events of The Orville season 2 finale, which presents an alternate timeline where organic life is on the run, and the Union lost their war against The Orville's Borg-like Kaylon. If Ed and Kelly never went on their second date, they'd never have married, divorced, and served together on the Orville during the first Kaylon attack. Realizing the galactic implications of her decision, the alternate Kelly tracks down the Orville crew and concocts a plan to avert this dark alternate timeline. Kelly and Claire successfully travel back in time to wipe the younger Kelly's memories so that she agrees to the second date with Ed, re-establishing The Orville main timeline with the couple's eventual separation in 2418.