Could The Expanse continue via a big or small screen spinoff? Thanks to an effective fan campaign and existing ties with Jeff Bezos, The Expanse narrowly avoided cancellation in 2018, following three seasons airing on the Syfy channel. Sadly, The Expanse season 6 now looks set to ground the Rocinante permanently. Thus far, The Expanse has adapted the first 5 books by James S.A. Corey, and Amazon's final run should continue that pace by adopting Babylon's Ashes as its foundation. But this still leaves the final 3 novels untouched, and with so many mysteries yet to be solved (in particular the aggressor race responsible for wiping out the Protomolecule creators), The Expanse season 6 may not provide the most conclusive of conclusions.
Intriguingly, The Expanse's creators have suggested the Rocinante might fly again in one form or another. Months before the second cancellation was announced, Andrew Kosove (producer) openly discussed the possibility of movies and spinoffs, and implied this might be how The Expanse's story would end if Amazon didn't green-light the full nine seasons. After the cancellation, Naren Shankar (showrunner) coyly hinted at more to come, refusing to rule out a continuation. What would a spinoff look like, and how could The Expanse season 6 pave the way for franchise expansion?
The Expanse's future revolves entirely around the 30-year time skip between books 6 and 7. Viewers have often wondered how The Expanse would overcome this obstacle in live-action, and the looming jump likely didn't help chances of renewal. Without giving away too much, Babylon's Ashes brings the war against Marco Inaros and the Free Navy to an end, and the dust is allowed to settle in the Sol System. When the action resumes in Persepolis Rising, a much older Rocinante crew find themselves in the midst of a new war against the Laconian Empire, while the lingering threat of the Protomolecule destroyers rumbles in the background. An Expanse spinoff series (perhaps under the title The Expanse: Tiamat's Wrath?) or several movie installments could deal squarely with these dual story threads - and the setup has already begun.
Cortazar's message to Admiral Sauveterre in The Expanse season 5's closing moments is sent from Laconia, and the striking last image of Protomolecule-fueled ships hints toward a villainous Empire under construction. If The Expanse were following the books exactly, this tease wouldn't be addressed until season 7. Since there is no season 7, two options are available - either blitz through the Laconia material in season 6, or save it for a spinoff. Obviously, most fans would find the latter preferable. The battle against Laconia is arguably the most detailed and intricate arc in the entire franchise, and attempting to mash that into season 6's Marco Inaros storyline could only result in an incoherent mess. A spinoff or movie provides all the time and space necessary to do The Expanse's final three books justice.
In this scenario, The Expanse's final season must leave breadcrumbs hinting at the Laconian conflict to come, rather than leaving fans to wonder whether the mysterious glowing vessels had been forgotten in the chaos of cancellation. Maybe a season 6 subplot can highlight the early days of Laconia, or the always-two-steps-ahead Avasarala (whose role in Babylon's Ashes is minimal) can begin investigating this potential growing threat from another system. These seeds would provide the foundation for a spinoff that then launches directly into Persepolis Rising.
The other major advantage to continuing The Expanse via a spinoff or movies is smoothing over the inevitable post-skip recastings. The 3-decade gap following The Expanse season 6 is a necessary evil, as it gives the Laconian Empire enough time to develop into a proper enemy. But making the current cast convincingly look 30 years older via makeup or CGI sounds all but impossible, meaning at least some of the Rocinante crew will need to be recast. If this happened in The Expanse season 7, viewers may not be receptive to the cast overhaul. In the context of a spinoff or movie, however, it's far easier to sell fans on an all-new cast playing older versions of Holden, Naomi and Amos.