Star Trek: Discovery Character Swap Explained by Actor Sara Mitich

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Sara Mitich discussed her decision to change characters during Star Trek: Discovery, a shift that many viewers didn’t notice. Star Trek: Discovery was key in launching the CBS All-Access streaming service (now Paramount+) in 2017, marking Star Trek‘s return to television after a 12-year hiatus. The show ran for five seasons, concluding in 2024.

Sara Mitich first appeared as the cyborg Lt. Commander Airiam in the third episode of Star Trek: Discovery season one, “Context is King.” Later, in season two, Hannah Cheesman took over the role of Airiam until the character’s death. Mitich then returned to the show as Lt. Commander Nilsson, this time without any prosthetics.

Sara Mitich discussed her decision to switch roles on Star Trek: Discovery during an appearance on the Star Trek and Chill podcast with hosts Ryan T. Husk, Malissa Longo, Charlynn Schmiedt, and Katie Nickolaou. She explained to John Orquiola from ScreenRant that while she enjoyed playing Airiam, she ultimately didn’t want to continue wearing the extensive prosthetics the role required. Here’s what she had to say:

Honestly, when Nilsson’s story started, I was totally lost! They really didn’t give us much warning about where things were headed – like when I suddenly found myself on that bridge, it just happened. And poor Airiam… we didn’t even realize she was ill until right before it occurred on screen. It was a surprise when the producers called me between seasons one and two. They offered me a new part – a chance to play with my own face, not hidden under prosthetics! It was for an engineer character, and they wanted to know if I was interested.

I initially agreed, but I wasn’t sure if it was the right decision because I didn’t know how things would turn out for either character. Ultimately, I took the role, mainly because of the extensive prosthetics involved. I really liked playing Airiam, but getting into the makeup took five hours! That meant arriving at 2:30 AM for a 7:00 AM start, and then another hour just to remove everything. Some days I was working for 20 to 22 hours straight.

I was thrilled when I found out I’d be taking over the role of Nilsson. A writer called to let me know Airiam was leaving the show and that I’d be stepping in on the bridge. It was an amazing and unexpected moment – I’ll never forget filming my first scene. There wasn’t any dialogue, but as I walked onto the bridge as Nilsson and approached Airiam’s station, I remember Anson Mount and the rest of the crew all looking at me. I hadn’t even been on the bridge set as an actor yet that season, and we were already ten episodes in!

I was involved in every episode of the first season. But in season two, I didn’t appear on screen until the tenth episode. As an actor, that shift was really interesting to navigate. It’s not every day you get to play two different characters on the same show, and that’s what’s great about science fiction.

Watch Sara Mitich on Star Trek and Chill below:

Sara Mitich frequently receives compliments for her portrayal of Airiam’s death in Star Trek: Discovery season 2, highlighting how many viewers were unaware a different actress originally played the role. The extensive prosthetics used for Airiam effectively concealed the change between Mitich and Hannah Cheesman, making the transition appear smooth.

As a longtime Trek fan, I was really interested to see how they handled Airiam’s departure. Sara Mitich stepped into a new role as Lt. Commander Nilsson, taking over as the spore drive officer on the Discovery bridge – she played Nilsson throughout season four. Then, when season five rolled around, they explained Nilsson’s absence by saying she’d been transferred to the Voyager-J, which I thought was a clever way to keep the character in the universe!

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Sara Mitich shared that personal challenges and significant life changes caused her to leave Star Trek: Discovery after season 5, which ultimately ended up being the show’s last season. During this time, she focused on her own well-being and created Gratitude and Growth, a podcast and platform designed to help others manage their emotions, stay grounded in the present moment, and develop lasting inner peace.

I’m a huge fan of Sara Mitich! She’s incredibly inspiring as a podcaster and speaker, really focusing on how to build wellness and become more emotionally strong. What’s amazing is that she’s also an actress – you might recognize her from shows like The Expanse and Star Trek: Discovery where she played roles like Airiam and Nilsson. It’s awesome how she uses both her acting and her expertise to help people grow!

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2026-02-24 14:09