For All Mankind's Killer Season 5 Cliffhanger Ending Explained By Showrunner [Exclusive]

T-minus 10 seconds until spoilers for the "For All Mankind" Season 5 finale.

"For All Mankind" Season 5 has come to an end, its Mars revolution story has concluded (for better or worse), and the show's larger story about the search for extraterrestrial life has borne fruit. Indeed, as the episode draws to a close, we hit all the big staples of a "For All Mankind" season finale, with a montage resolving loose threads and a big jump forward in time that introduces another decade.

But something's different this time. Rather than an uplifting look at some new technology or human achievement, we get an ominous scene that takes place near a ringed planet and involves a derelict ship adrift in space — a vessel with no crew and a gaping hole, at that.

This is Mars-94, from all the way back in "For All Mankind" Season 3. It's a foreboding and otherwise mysterious moment straight out of an "Alien" movie or even the "Dead Space" video games. Speaking with /Film, showrunners Ben Nedivi and Matt Wolpert shed some light on this cliffhanger and how it adds a new mystery for Season 6.

"I think the moment before that with Kelly [played by Cynthy Wu] and her discovery is hopeful and optimistic and kind of like, 'Oh my God, where will this lead?' So, it did feel like an opportunity there at the end to leave the audience with something a little more mysterious," Nedivi explained. "It was more mystery that we were going for there in terms of this dead ship from the past of the show, but then that message at the end that you see on it does hint at, I think, where we're going next season and kind of this path to discovery."

According to Matt Wolpert, the return of Mars-94 will very much factor into the sixth and final season of "For All Mankind." "Those two things, the Kelly walking into that methane lake and being surrounded by life, and then the mystery of what it says on Mars-94, is kind of the central thrust of Season 6," Wolpert noted. "Continuing that discovery and all the unexpected places it will take us."

It's not just that Mars-94 has returned; it's the vagueness of its location and the final message on its computer that are intriguing. Though it looks like the ship is orbiting Saturn, we don't know for sure. With the "For All Mankind" universe housing all manner of fantastical technology, it's not beyond the realm of possibility that the vessel could have somehow drifted far enough over 30 years to escape our Solar System and reach some unknown planet.

Moreover, the final shot of the season — a computer activating with a message in Russian — indicates there's more here than meets the eye. When translated, the message reads "D:/ Detection of GW 3.06.0451 // Nikulov Loading..."

"Nikulov" seemingly refers to Sergei Nikulov (Piotr Adamczyk), a Soviet engineer and director of the Mars-94 space mission who died in Season 4. Similarly, GW could mean "gravitational wave," a ripple in space-time that is caused by things like black holes and are key to the theory of relativity. The rest of the message is an enigma for now, but it's plausible this will all be connected to some form of technology that allows humanity to actually leave our solar system in Season 6.

The first five seasons of "For All Mankind" are now streaming on Apple TV.