5 Star Trek: Discovery Characters Who Left Burnham’s Ship (& Who Came Back)

Warning: SPOILERS for Star Trek: Discovery Season 5.

Summary Captain Michael Burnham has been the central focus of Star Trek: Discovery, with other crew members taking on supporting roles.

Crew members such as Ronald Bryce, Nhan, Nilsson, Tilly, and Saru have moved on to different positions within Starfleet.

The dynamic of the USS Discovery crew has evolved over the seasons, reflecting a more realistic representation of typical Starfleet careers.

The USS Discovery has seen crew members come and go over the course of Star Trek: Discovery's five seasons. More than any other Star Trek show that came before it, the story of Discovery is centered on one character — Captain Michael Burnham (Sonequa Martin-Green). While many of the crew members of the titular ship have come to feel like family, Discovery's primary focus has always been Michael and her journey from infamous mutineer to accomplished Starfleet Captain. With an actress as talented as Sonequa Martin-Green at the helm, this focus often works in the show's favor, but it does mean some of the other cast members get less screen time.

The crew of the USS Discovery never coalesced into a cohesive whole the same way other Star Trek crews have, and several crew members moved on as the show progressed. Some secondary and even a couple of main characters have moved on from Discovery and taken other positions within Starfleet or the Federation. While this sometimes means the characters are written out of Star Trek: Discovery (at least temporarily), it also feels more realistic for a typical Starfleet career. It never quite made sense, for example, that Commander William Riker (Jonathan Frakes) remained First Officer on the USS Enterprise-D for 15 years despite being offered numerous promotions.

Related Star Trek: Discovery Season 5 Returning Cast & New Character Guide As Burnham seeks the universe's greatest treasure in Star Trek: Discovery season 5, she'll need help from a host of new and returning characters.

5 Lt. Commander Ronald Bryce

Transferred to the USS Curie & Worked at Federation Headquarters

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Beginning in Star Trek: Discovery season 1, Lt. Ronald Bryce (Ronnie Rowe Jr.) served as the communications officer on the USS Discovery's bridge. Although Bryce has rarely featured in Discovery's main storylines, he was a staple on the bridge for most of Discovery's first four seasons, often relaying incoming transmissions. He chose to remain on board Discovery when Michael Burnham led the ship into the 32nd century, remaining at comms.

Bryce was promoted to Lt. Commander and consulted on the USS Curie.

Bryce was promoted to Lt. Commander and consulted on the USS Curie. In his last appearance in Star Trek: Discovery season 4, Bryce was working with Dr. Kovich (David Cronenberg) at Federation Headquarters, looking for a way to communicate through the Galactic Barrier. In Bryce's only appearance in Star Trek: Discovery season 5 so far, he was on the bridge when Captain Burnham and Commander Rayner (Callum Keith Rennie) time traveled to Discovery's past in Star Trek: Discovery season 5, episode 4, "Face the Strange."

4 Commander Nhan

Transferred to the USS Tikhov & the USS Locherer

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Prior to joining the crew of the USS Discovery, Commander Nhan (Rachael Ancheril) served as an engineer on the USS Enterprise under the command of Captain Christopher Pike (Anson Mount). Nhan accompanied Pike when he took over command of Discovery, and she later transferred to the new ship, eventually becoming Chief of Security. After Discovery traveled to the 32nd century, they encountered the USS Tikhov, a seed vault ship crewed by Barzans.

As a Barzan, Nhan had not seen her own people since joining Starfleet, and she volunteered to travel with the ship back to the Barzan homeworld. Nhan only remained on Barzan for a short time, after which she joined Federation Security. In this position, she briefly returned to Discovery to aid in the pursuit of Dr. Ruon Tarka (Shawn Doyle) and Cleveland Booker (David Ajala) in Star Trek: Discovery season 4. Nhan returned again in Star Trek: Discovery season 5, episode 7, "Erigah," as the security officer in charge of captured prisoners L'ak (Elias Toufexis) and Moll (Eve Harlow).

Related Star Trek: Discovery Season 5 Episode 7 Ending Explained Star Trek: Discovery's crew locates the final clue to the Progenitors' treasure, but a shocking twist brings the Breen to the Federation's door.

3 Lt. Commander Nilsson

Transferred to the USS Voyager-J

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Since the premiere of Star Trek: Discovery season 2, Lt. Commander Nilsson (Sara Mitich) has been a regular fixture on the bridge of the USS Discovery. After the death of Lt. Commander Airiam (Hannah Cheesman), Nilsson took over the role of spore drive operations officer. Like most of the crew, Nilsson volunteered to stay on Discovery for its trip to the future, and she helped Commander Paul Stamets (Anthony Rapp) and Commander Jett Reno (Tig Notaro) repair the ship after its journey.

Nilsson was occasionally left in command of the USS Discovery's bridge when the other senior officers were away on a mission or otherwise occupied. Sometime after Discovery returned from the other side of the Galactic Barrier and their mission to communicate with Species 10-C at the end of Star Trek: Discovery season 4, Nilsson accepted a position on the USS Voyager-J. Nilsson had a (neutered) pet Tribble that she left with Lieutenant Christopher (Orville Cummings) after her departure.

Sara Mitich portrayed Lt. Commander Airiam in Star Trek: Discovery season 1, before Hannah Cheesman took over the role.

2 Lt. Sylvia Tilly

Began teaching at Starfleet Academy

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After her introduction in Star Trek: Discovery season 1, Lt. Sylvia Tilly (Mary Wiseman) quickly became one of Star Trek's most relatable characters. Tilly's endearing enthusiasm and hesitant friendship with Michael Burnham made her difficult to dislike, and she has grown into one of the USS Discovery's most accomplished and well-rounded officers. Tilly began her Discovery career as a cadet with dreams of sitting in the Captain's chair one day, but her plans for the future have shifted over time.

When the USS Discovery arrived in the 32nd century, Tilly served as the ship's First Officer under the command of Captain Saru (Doug Jones) and, later, Captain Burnham. Having been promoted to Lieutenant junior grade, Tilly began exploring other career opportunities outside of her comfort zone. Based on their therapy sessions, Dr. Hugh Culber (Wilson Cruz) recommended Tilly to lead a training exercise for a group of Starfleet cadets. Tilly excelled at this assignment and later accepted a teaching position at Starfleet Academy.

The upcoming Star Trek: Starfleet Academy show will tell the story of a new class of Starfleet cadets, but it remains unknown whether Tilly will have a presence in the show.

During the Dark Matter Anomaly crisis, Tilly remained at Federation Headquarters and aided Admiral Charles Vance (Oded Fehr) in the evacuation of Earth. When Discovery took on the Red Directive mission to find the Progenitors' technology in Star Trek: Discovery season 5, Tilly rejoined the ship's crew as a science advisor. Tilly has since proven to be invaluable in the search for the five clues that lead to the Progenitors' treasure. She has helped Stamets and Ensign Adira Tal (Blu del Barrio) in the science lab, and accompanied Captain Burnahm on an away mission to Halem'no to find the fourth clue.

Related Tilly’s 6 Star Trek: Discovery Away Missions Explained For Star Trek: Discovery's Lt. Sylvia Tilly, being part of Star Trek away missions don't just advance the plot -- they make Tilly a better character.

1 Captain Saru

Became a Federation Ambassador

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The first Kelpien in Starfleet, Saru served as a Science Officer on the USS Shenzhou under the command of Captain Philippa Georgiou (Michelle Yeoh) when Star Trek: Discovery began. Saru was serving on the ship when Michael Burnham first joined the crew, making him the character who has known her the longest. Following Georgiou's death, Saru became First Officer of the USS Discovery under the command of Captain Gabriel Lorca (Jason Isaacs). Saru later took over command of Discovery, helping lead the ship into the 32nd century.

After the crew of the USS Discovery solved the mystery of the Burn in Star Trek: Discovery season 3, Saru left the ship for a time to serve as a member of his village council on Kaminar. When Saru returned to Discovery in the show's fourth season, he took on the role of First Officer with Michael Burnham as Captain. In Star Trek: Discovery season 4, Saru began a tentative romance with Ni'Var President T'Rina (Tara Rosling) and the two decided to marry in Star Trek: Discovery season 5.

Saru has had one of Star Trek: Discovery's best character journeys.

Because of his exemplary service to the Federation and Starfleet, Saru was offered a position as a Federation Ambassador. Not only would this position play to Saru's strengths, but it would also allow him to be closer to T'Rina. After one last away mission with Burnham, Saru resigned his Starfleet commission and accepted the role of Ambassador, and he has been largely absent from much of Discovery season 5 as a result. Still, Saru has had one of Star Trek: Discovery's best character journeys, and he will no doubt make another appearance before the show comes to an end.

New episodes of Star Trek: Discovery stream Thursdays on Paramount+.