Sara Mitich explains why she changed characters on Star Trek: Discovery, a switch that most fans didn’t even realize had occurred. Star Trek: Discovery helped launch the CBS All-Access streaming service (which became Paramount+) in 2017, bringing Star Trek back to TV after 12 years. Star Trek: Discovery ran for five seasons, concluding in 2024.
As the cyborg Lt. Commander Airiam, Sara Mitich debuted in Star Trek: Discovery season 1, episode 3, “Context is King.” However, when Airiam returned in Star Trek: Discovery season 2 until her death later that season, the cyborg spore drive operations officer was portrayed by Hannah Cheesman. Mitich began appearing without prosthetics as Lt. Commander Nilsson.
Appearing on the Star Trek and Chill podcast hosted by Ryan T. Husk, Malissa Longo, Charlynn Schmiedt, and Katie Nickolaou, Sara Mitich answered a question from ScreenRant‘s John Orquiola about how and why she changed characters on Star Trek: Discovery. As much as Mitich “loved” playing Airiam, she said it came down to no longer wanting to wear the character’s prosthetics. Read Sara’s quote below:
I didn’t know where Nilsson was going. Nobody told me I’d end up on the bridge. We didn’t even know Airiam was dying until two episodes before it happened… Between season 1 and season 2, they called me, and they were like, ‘Hey, we’ve got this new role coming up. You wouldn’t be in prosthetics, it would be your face. It’s an engineer. Do you want it?’
I was like, ‘Yes,’ but also, I was like, I don’t know what the right answer is here because I didn’t know what was going to happen with either character. But I ended up taking it, honestly, because the prosthetics were a lot. I loved Airiam, but it was also… when we started Airiam, it took me 5 hours to get into [prosthetics]. So my call times were 2:30 in the morning for a 7am call, and it took me an hour to get out of it. I was pulling 20 to 22 hour days sometimes.
So, I decided to take Nilsson, and I’m so grateful… One of the writers called me to tell me that Airiam’s going to be off [the show] and I’m going to replace her on the bridge. And I was like, this is so cool and also so wild. I’ll never forget that moment filming it. There’s no dialogue, but when I walk out to the bridge [for] the first time as Nilsson and I walk to Airiam’s station, even filming it, I remember Anson [Mount] looking at me, everyone looking at me, and I hadn’t been on the bridge that season yet as an actor. And we were 10 episodes in.
Season 1, I was there all the time with everybody. And then [in] season 2, I wasn’t on the bridge until episode 10. So… as an actor on the back end of it, it was a very interesting transition. I mean, how many people can say they’ve done two characters on one show? That’s the beauty of sci-fi.
Watch Sara Mitich on Star Trek and Chill below:
Sara Mitich says she is often praised for her performance during Airiam’s death in Star Trek: Discovery season 2, which shows how most viewers didn’t realize that a different actor played the role. Because Airiam’s prosthetics made the actor wearing them unrecognizable, the switch between Mitich and Hannah Cheesman was seamless.
Sara Mitich joins an elite list of actors who played two characters on the same Star Trek show, which includes Jeffrey Combs, who played Liquidator Brunt and Weyoun, and Tony Todd, who played Kurn and the adult Jake Sisko on Star Trek: Deep Space Nine.
As Lt. Commander Nilsson, Sara Mitich’s new character replaced her old one, taking the late Airiam’s position as spore drive operations officer on the USS Discovery’s bridge. Mitich continued as Nilsson until the end of Star Trek: Discovery season 4. Nilsson’s absence from Star Trek: Discovery season 5 was explained by her character being transferred to the USS Voyager-J.
Sara Mitich explained that personal issues and profound changes in her life led to her not appearing in Star Trek: Discovery season 5, which unexpectedly turned out to be its final season. Mitich went on her own journey of discovery that led her to found Gratitude and Growth, Sara’s podcast and platform aimed at helping people regulate their emotions, return to presence, and build inner steadiness sustainably.
As a podcaster and keynote speaker, Sara Mitich promotes wellness, emotional resilience, and personal growth. Mitich’s career as an emotional regulation expert is aided by her fame from her acting roles in sci-fi sagas like The Expanse and Star Trek: Discovery, whether fans know her as Airiam, Nilsson, or both.
