Memory Alpha
Memory Alpha
Multiple realities
(covers information from several alternate timelines)

Number One redirects here; for additional meanings of "number one", please see number one.
"I don’t care where you come from. You're the best first officer in the fleet."

Lieutenant Commander Una Chin-Riley, commonly known professionally as Number One, was a female Illyrian Starfleet command division officer who lived during the mid-23rd century. Through the 2250s, she served aboard the USS Enterprise as Christopher Pike's executive officer and helmsman. (TOS: "The Cage"; DIS: "An Obol for Charon")

Early life[]

Una and her parents

Una and her parents in their youth

Chin-Riley was born on Illyria in the early 23rd century. As a member of the Illyrian species, Chin-Riley was genetically-engineered before birth, as it was part of her family tradition and heritage. (SNW: "Ad Astra per Aspera") Her physical strength was greatly improved, allowing her to carry a grown person with no visible effort, while her immune system would also glow, and as well, could burn out infectious agents from her body without having to rely on antibodies. (SNW: "Ghosts of Illyria", "Ad Astra per Aspera")

Chin-Riley grew up on a Federation colony in the Vaultera Nebula. She had one brother. (SNW: "Ad Astra per Aspera")

In her personnel file, Chin-Riley was said to have been born on Illyria or on Colony 9-A. However, a notation to her file stated that verification of her being born on this colony was pending and that the information came from an unreliable source.

Additional notations to her file state that Chin-Riley's parents and brother were possibly deceased. Like her dob (date-of-birth), the verification of this information was pending and that the information came from unreliable sources.

When she was five or six years old, encountered Starfleet crew that visited her planet. According to her, "They were all so... different from one another. So many crew members from so many planets. It was beautiful. I thought if all those people from all those worlds can work together, side by side, maybe I could, too. Maybe I could be a part of something bigger than myself." (SNW: "Ad Astra per Aspera") Her dream of joining Starfleet, however, due to the Federation ban on genetic engineering, she had to hide her true nature and history. (SNW: "Ghosts of Illyria")

Later, she fractured her leg after she attempted to stop a fight at school, which had broken out after one boy had accused another of being an Illyrian. In spite of the break being a simple fix with modern medicine, her parents wouldn't take her to a hospital out of fear of being arrested. In spite of her modifications, the leg became infected, and she nearly died, until she was able to be treated by a Illyrian doctor who visited her family in the middle of the night. (SNW: "Ad Astra per Aspera")

Starfleet career[]

Starfleet Academy[]

Captain Robert April sponsored Chin-Riley's application to Starfleet Academy. (SNW: "Ad Astra per Aspera")

She first met Christopher Pike following an inspiring speech he gave at the Academy. (SNW: "Ad Astra per Aspera")

She had Pelia for an Instructor for Starship Maintenance 307 and was given a "C" on her final paper, a "C" Pelia felt was sloppy but well deserved. (SNW: "Lost in Translation")

Early postings and assignments[]

In 2234, Chin-Riley began her Starfleet career. (SNW: "Ad Astra per Aspera")

In her personnel file, it was stated that she was a member of the graduating class of 2335.

As an ensign, was assigned to the USS Martin Luther King Jr. During her assignment aboard the "King Junior", she was involved in the rescue of La'an Noonien-Singh. (SNW: "Strange New Worlds")

While questioning Ensign Zier, Chin-Riley sympathized, saying that she, too, was once an ensign, and understood being nervous. (SNW: "Spock Amok")

At some point in her early career, Chin-Riley served aboard the USS Antares, the USS Chatelet, and the USS Aryabhatta, all ships that her future commanding officer Christopher Pike also served on. (DIS: "Brother"; SNW: "Memento Mori", "Ad Astra per Aspera"; display graphic)

According to Pike, Chin-Riley had a habit of jumping from department to department, although she claimed that it only happened once. (SNW: "Children of the Comet")

On her personnel file, the name of one of her postings is redacted, with the information about it being restricted.

Service aboard the Enterprise[]

Una Chin-Riley, 2253

Number One on the bridge of the USS Enterprise

Upon her assignment as science officer to the USS Enterprise under the command of Captain April, she witnessed a triple-mode high-amplitude Delta Scuti star on her first deep-space cruise that took her within a half light year of 99 Pegasi. (ST: "Q&A"; SNW: "Ad Astra per Aspera"; display graphic)


In 2248, Captain April recommended to Starfleet Command that Una Chin-Riley receive the Starfleet Medal of Gallantry for her actions during the Marcel disaster. (SNW: "Ad Astra per Aspera")


In 2250, Chin-Riley was assigned as the first officer of Enterprise under the command of Captain Pike, also serving as the ship's helmsman. She went professionally by the name "Number One". (TOS: "The Cage"; ST: "Q&A"; SNW: "Ad Astra per Aspera" display graphic) Before she took up her new position, Chin-Riley spent a week shadowing Pike, a week she later believed made all the difference in her performance as first officer. (SNW: "Subspace Rhapsody")


Una and Spock in the turbolift

Lieutenant Una Chin-Riley and Ensign Spock in 2253

In 2253, Number One greeted Ensign Spock on his first day aboard the Enterprise after departing from Starbase 40. She encouraged him to barrage her with questions, which he returned in kind. While talking, however, the two were trapped in a turbolift, where they bonded and Una gave advice to the young officer before they were rescued by Lieutenant Amin. (ST: "Q&A"; SNW: "Ad Astra per Aspera", "Among the Lotus Eaters" display graphic)


By 2254, she was considered one of the most experienced members of the crew. According to the Talosian magistrate known as The Keeper, she had "the superior mind and would produce highly intelligent children", adding that, "Although she seems to lack emotion, this is largely a pretense. She has often had fantasies involving [Pike]." (TOS: "The Cage")

Number One, Pike, Colt, and Vina imprisoned

Number One with the captives on Talos IV

With Pike kidnapped by the Talosians, Number One led the effort to rescue him, first by unsuccessfully attempting to use a laser cannon to blast open an entry to a Talosian underground lair where Pike was being held, and then by using the transporter in an attempt to infiltrate this lair. Number One was subsequently kidnapped, along with Yeoman Colt, for the purpose of providing Pike with a mate with whom he could procreate. In response to this, Una set her laser pistol to overload, telling the Talosian Keeper that it was wrong to keep a colony of Humans as slaves, and that they would rather die. This, combined with an examination of the Enterprise's historical records, convinced the Talosians that Humans' unique hatred of captivity made them nonviable subjects, and they were subsequently allowed to return to the Enterprise. (TOS: "The Cage")

Footage of her experience aboard the Enterprise under Captain Pike during the original visit to Talos IV, from thirteen years prior, was transmitted from that planet during Spock's fictional court martial aboard the same ship in 2267. (TOS: "The Menagerie, Part I", "The Menagerie, Part II")


Like most of the Enterprise crew, Number One sat out the Klingon War which, like it did to everyone else aboard the Enterprise, took its toll on her. (DIS: "Brother")


Pike and Number One

Una lends a hand to Pike aboard Discovery

In 2257, Chin-Riley remained with the ship while it underwent major repairs, only briefly visited Pike aboard the USS Discovery to provide him with information on Spock's recent escape from Starbase 5. The two officers sat and talked briefly in the mess hall. During their conversation, Una admitted that she went through unofficial channels to obtain the information, noting that the entire situation was extremely odd. Una stated plainly that she was not going to let Spock go without a fight and Pike noted that as usual they both were in agreement. Before they parted she warned Pike to be careful and Pike told her the same. She returned to the Enterprise shortly thereafter. (DIS: "An Obol for Charon")


Number One, 2258

Number One in 2258

In 2258, following the mission to get a time crystal from the monastery on Boreth, Christopher Pike asked R.A. Bryce to send a message to the Enterprise's XO, Number One, to have the Enterprise rendezvous with the Discovery to take on the Discovery's crew. (DIS: "Through the Valley of Shadows")

During the Battle near Xahea, Number One manned the helm of the Enterprise, and later worked with Admiral Katrina Cornwell in an ultimately unsuccessful attempt to disarm an undetonated photon torpedo that had lodged in the saucer section's hull.

After the disappearance of the Discovery, Pike, Ash Tyler, and Number One were debriefed at Starfleet Command in San Francisco. Following the debriefing, Number One and the others who knew of the Discovery's fate were sworn to never speak of the Discovery or its crew again.

After a hundred and twenty four days of repair, Lieutenant Chin-Riley was still aboard the Enterprise as it traveled to Edrin II. (DIS: "Such Sweet Sorrow, Part 2")


In 2259, the Enterprise returned to Earth for scheduled maintenance. Because she did not deal well with downtime, Number One was assigned to command the USS Archer to initiate a first contact mission to Kiley 279 after Starfleet detected signs of warp drive on the planet. However, the Kiley had in fact developed a warp bomb based on observations made from the battle near Xahea. The Kiley reacted negatively towards the first contact overtures and Number One, as well as the two other members of the Archer's crew, were wounded and captured by the Kiley.

After Number One and the Archer crew were rescued by Pike and an Enterprise away team, Number One returned to her post as first officer of the Enterprise. (SNW: "Strange New Worlds")

When the Enterprise was infected by a light virus, Una proved to be the only person immune to it, due to her undisclosed status as a genetically modified Illyrian. With Captain Pike trapped on the surface of a former Illyrian colony, Una assumed command and initiated a ship-wide lockdown. While she could not pass antibodies on directly to the crew to cure the contagion, she was able to engineer a situation where she could induce the same antibodies in La'an Noonien-Singh, which could then be used to save the others. When the crisis had passed Una disclosed her genetic identity to Pike and offered her resignation, but he refused to accept it as he considered Una 'the best first officer in the fleet'. (SNW: "Ghosts of Illyria")

Una was seriously injured during a surprise attack by the Gorn, sustaining shrapnel wounds to her abdomen that could not be treated conventionally due to battle damage. With dwindling medical supplies available, Una ordered that the last remaining supply of blood plasma be given to another injured crewmember that needed it. Christine Chapel was able to treat her wounds with her knowledge of archaeological medicine, and Joseph M'Benga donated his own blood to aid Una's recovery, ignoring the stigma that existed at the time regarding Humans and Illyrians sharing blood. (SNW: "Memento Mori")

When an alien consciousness from the Jonisian Nebula brought the fairy tale The Kingdom of Elysian to life on the Enterprise, Una was used for the character of Z'ymira the Huntress. Una had no memory of the events after the ship was returned to normal. (SNW: "The Elysian Kingdom")

While Captain Pike resolved to protect her from Starfleet, Una was arrested a few months later when her illegal genetic status was revealed. When a team of officers from the USS Cayuga arrived to arrest Una, Pike physically intervened on her behalf. Una warned him not to fight back, as she had known that such an outcome was likely. As she was beamed away, Captain Pike vowed that he would fight on her behalf. (SNW: "A Quality of Mercy")

Una's commendations, by the time of her arrest, included Starfleet Award of Valor, Medal of Excellence, Order of Tactics, Legion of Honor, and Medal of Commendation. (SNW: "Ad Astra per Aspera" display graphic)

Una remained in Starfleet custody pending trial for concealing her genetic heritage, while Captain Pike attempted to secure her a good lawyer. (SNW: "The Broken Circle")

Before her court martial, Una was offered a deal by Captain Marie Batel where Una would go free in exchange for a dishonorable discharge, but she refused the deal. Subsequently and in retaliation, two sedition charges were added (falsifying her records and violating Starfleet's code against genetic engineering), leaving Una facing twenty years in a Federation penal colony.

Pike was able to secure Una the help of her former best friend Neera Ketoul, who used Una's trial as a platform to overturn the genetic modification law, and to broadcast her hatred of Federation policies regarding Illyrians. Katoul had Una retell the history of discrimination and persecution that she had faced, eventually admitting that she had turned herself in, as she was tired of living a lie. Katoul argued that, in essence, Una had sought asylum with Starfleet from the hardships she faced for being an Illyrian, and that Pike had exercised his judgement and granted it to Una after she had revealed herself to him.

Although the Federation wasn't willing to change their laws regarding genetic engineering for the time being, Una was acquitted, officially granted asylum and allowed to return to duty as first officer of the Enterprise. Una reconciled with Katoul, who saw Una's exoneration (and being allowed to openly serve as an Illyrian commander on a Federation starship) as a first step towards change. (SNW: "Ad Astra per Aspera")


"Numero Una. Hottest First Officer in Starfleet history."
Una Chin-Riley's recruitment poster

A Starfleet recruitment poster featuring Una Chin-Riley

Despite Starfleet's attempt to use Una as a scapegoat for their anti-Augment stance, Una would go on to be remembered as one of the finest first officers in Federation history. By 2381, recruitment posters featuring Una were widely distributed, with Ensign Brad Boimler keeping one in his bunk onboard the USS Cerritos, citing it and her as his inspiration for joining Starfleet. Una was initially horrified to learn of her status as a 'pin-up' from Beckett Mariner, but was deeply moved upon learning the full context, particularly due to the poster's use of Starfleet's "Ad Astra per Aspera" motto. (SNW: "Those Old Scientists")

Personal interests[]


Chin-Riley secretly enjoyed the music of Gilbert and Sullivan. When trapped in a turbolift with Spock on his first day on the Enterprise, she sang "I Am the Very Model of a Modern Major-General", but ordered Spock to forget it. (ST: "Q&A"; SNW: "Ad Astra per Aspera")

She also enjoyed spicy food. When she met Pike on Discovery, she ordered a cheeseburger and french fries with habanero sauce. (DIS: "An Obol for Charon") Her comfort food, however, was strawberries. (SNW: "Ghosts of Illyria")


La'an Noonien-Singh[]

Una and La'an met when Chin-Riley met when she was an Ensign aboard the USS Martin King, Jr.. The two would strike up a friendship that would last for a long time. La'an would affectionally call Una "Chief", and Una would come to act as a mentor for her. (SNW: "Strange New Worlds")

Christopher Pike[]

Pike and Una hug

Pike and Una hugging

Una and Christopher Pike first met when he gave a speech to her Academy class about a test mission he had flown. Following Pike's speech, Chin-Riley approached him and pointed out a flaw he had made during reentry. He found it bold and annoying but recognized that she was correct. Over the years, the two would be assigned to several vessels including the USS Enterprise. When Pike was made captain of the Enterprise he promoted Chin-Riley to First officer. (SNW: "Strange New Worlds", "Ad Astra per Aspera")

When Pike learned of Chin-Riley's Illyrian heritage, he told her that he didn't care and that he would deal with fallout with Starfleet. (SNW: "Ghosts of Illyria")

Una would keep a photograph of the two of them in her quarters aboard the Enterprise. Upon her return to the ship following her exoneration, a visibly relieved Pike hugged Una before regaining his composure. (SNW: "Ad Astra per Aspera")

Alternate timelines[]

In an alternate timeline where Pike was able to avoid his crippling fate, he asked La'an Noonien-Singh about Una. La'an told him that Una wasn't allowed to have contact with anyone. Spock later revealed that in this timeline, Una had been locked up in a Federation prison colony for nearly seven years for her illegal modifications. (SNW: "A Quality of Mercy")

Awards and honors[]

Carrington Award
Federation Citation of Honor
Legate's Crest of Valor
Medal of Commendation
Order of Tactics
Proficient Service Medallion
Scientific Legion of Honor
Silver Palm with Cluster
Starfleet Award of Valor
Starfleet Citation for Conspicuous Gallantry
Starfleet Medal of Gallantry

Key dates[]



Background information[]

Number One, 2254

Number One's original portrayal by Majel Barrett

Number One was originally portrayed by Majel Barrett in the Star Trek pilot, "The Cage", but credited as M. Leigh Hudec for her subsequent archival appearance featured in both episodes of "The Menagerie". When her character was reintroduced for Star Trek: Discovery, and its subsequent spin-offs, she was portrayed by Rebecca Romijn. Additionally, Anna Claire Beitel portrayed Una as a child in "Ad Astra per Aspera".

In the original version of the series outline Star Trek is... (as reprinted in The Making of Star Trek, pp. 22-30), Number One was initially described as "a glacierlike, efficient female who serves as ship's Executive Officer." (The Making of Star Trek, p. 24) A more detailed description of the character from exactly the same document stated;

The Executive Officer
Never referred to as anything but "Number One", this officer is female. Almost mysteriously female, in fact – slim and dark in a Nile Valley way, age uncertain, one of those women who will always look the same between years twenty and fifty. An extraordinarily efficient officer, "Number One" enjoys playing it expressionless, cool – is probably Robert April's superior in detailed knowledge of the equipment, departments, and personnel aboard the vessel. When Captain April leaves the craft, "Number One" moves up to Acting Captain. (The Making of Star Trek, p. 29)

In the scripts of "The Cage", Number One was described as "Female, slim and dark in a Nile Valley way, age uncertain, one of those women who will always look the same between the ages of twenty and fifty [....] Almost glacier-like in her imperturbability and precision. From time to time we'll wonder just how much female exists under that icy facade." She was also scripted to be slightly more wary of J.M. Colt than she is in the final version of the episode, such as being initially reluctant about allowing her to join a landing party assigned to rescue the captain. [1]

Number One was dropped from the series as NBC executives did not respond well to her character. Reactions to her in the screen test of "The Cage" were also poor (by the women more negatively than the men, according to Gene Roddenberry). Her highly logical, steel-trap mind was given to the character of Spock in "Where No Man Has Gone Before" and maintained there onward.

Although Majel Barrett-Roddenberry was credited as Majel Barrett in the unaired episode "The Cage", she was credited as "M. Leigh Hudec" – Barrett's birth name – in the televised two-part episode "The Menagerie, Part I" and "The Menagerie, Part II", because the production team was endeavoring to hide from NBC the fact that the actress, not to be signed for either the second pilot or the regular show as had been demanded by the network, had actually returned to Star Trek: The Original Series as the recurring Nurse Christine Chapel by Gene Roddenberry's doing. (Inside Star Trek: The Real Story, 1997, pp. 223-224; These Are the Voyages: TOS Season One, 1st ed, pp. 25-27) An unintended ironic twist in Star Trek history was that when Roddenberry surreptitiously brought the natural brunette Barrett back on the Original Series, he had her also disguised as a blonde to mislead the NBC network executives, who adamantly did not want her back on the show, whereas the natural blonde Romijn had to have her hair dyed to have her appear as the brunette Number One in Discovery.

In "The Cage", Number One was referred to as "lieutenant." Within Starfleet, it was rare for a lieutenant to serve as the first officer of a starship. The likely reason she was originally assigned this rank was that, when Gene Roddenberry first created Star Trek, the rank structure he employed was based on that of the 18th and 19th century Royal Navy, in which a ship's second in command was generally a first lieutenant, rather than the ranks used by the 20th century United States Navy we have come to associate with Starfleet. George Kirk is the only other known instance of a lieutenant serving as a ship's first officer.

In Number One's subsequent appearances in Star Trek: Discovery and Star Trek: Short Treks, her rank insignia is indicates she was a lieutenant, although she was identified as a lieutenant commander on a PADD in "Q&A", which takes place before "The Cage". By Star Trek: Strange New Worlds, Chin-Riley wore the insignia of lieutenant commander and has been repeatedly identified as such in the show. There was at least one instance, however, where, in an apparent art design error, she is clearly listed as "Lt. Una" on an internal communication in the episode "Subspace Rhapsody".


Did I mumble?

In an interview with TrekCore, the co-writer of "Such Sweet Sorrow, Part 2" and Star Trek: Discovery third season co-showrunner Michelle Paradise confirmed that Christopher Pike called Number One "Una" in that episode. [2] This is one of several names which had been used for this character in non-canon material. Subtitles on Netflix and the second season Blu-ray release misspelled it as "Noona" (the Netflix subtitles have since been corrected), while the CBSAA captions say that he merely said "and, uh..." while transitioning to a question directed at Admiral Cornwell. Dialogue and PADD graphics in the Star Trek: Short Treks episode "Q&A" definitively confirm that Number One's name is "Una," and that she insists on being addressed as "Number One".

According to The Autobiography of Mr. Spock, Una's full name is Una Chin-Riley, a fact later revealed in the Strange New Worlds premiere episode "Strange New Worlds".


In the Marvel Star Trek: Early Voyages comic book series, this character was named Lieutenant Commander Robbins. Her first name was interrupted by other dialogue, but starts with "Eure-."

The novel Vulcan's Glory, by Star Trek: The Original Series writer D.C. Fontana, suggested this character's moniker was not simply a nickname or title – she was an Illyrian who was called "Number One," as the best intellect among her generation. The novels The Children of Kings and Child of Two Worlds explain that Number One does have a given name, but it's difficult to pronounce for non-Illyrians; the former suggests that she liked to be called by this name rather than her own as it enabled her to maintain a professional relationship with her captain. The novel The Enterprise War describes her as having been raised in Illyrian colonies and thus, while not actually being Illyrian herself, having adapted much of that species' emotional self-control. Her actually being Illyrian and raised in an Illyrian colony was confirmed canon in SNW: "Ghosts of Illyria".

In the novel Captain to Captain she is referred to as "Una". The novel explained that she had adopted the name Una as far back as her Academy days, due to her real name being all but impossible to pronounce. The name "Una" was also used in the Star Trek: Discovery novel Desperate Hours and was subsequently used in DIS: "Such Sweet Sorrow, Part 2" and ST: "Q&A".

Star Trek II: Biographies gives her real name as Leigh Hudec (after "M. Leigh Hudec", the name under which Majel Barrett was credited in The Cage).

Peter David's New Frontier series of novels had a character named "Morgan Primus" who was an immortal like Flint (from TOS: "Requiem for Methuselah") and was the mother of Robin Lefler. It is hinted that she and Number One are the same person.

In the Captain's Table novel Where Sea Meets Sky, Number One was given the last name "Lefler" (an allusion to Robin Lefler).

The early days of Number One were chronicled in the IDW Publishing miniseries Star Trek: Crew.

In the IDW Publishing comic Star Trek: Romulans - Schism, she is a commodore in command of the USS Yorktown testing the cloaking device stolen from the Romulans during the events of "The Enterprise Incident". No name is mentioned.

In the miniseries Star Trek: Leonard McCoy, Frontier Doctor, Number One was promoted to admiral in the 2270s and continued to command the Yorktown.

In the first issue of the 2013 comic series Star Trek: New Visions, Kirk, Spock, and McCoy report to a commodore who is not named but is clearly Number One and Spock did say it was pleasant to see her again.

In Who's Who in Star Trek, Number One is said to have been descended from colonists on a planet inhabited by telepathic humanoids who are peaceful. She is described as having entered Starfleet after saving the life of Earth's leader when his shuttle crashed on her planet, he having waived all psychological and physical testing on her behalf. She is also described as having suffered severe injuries just prior to the end of Pike's tenure as captain of the Enterprise, forcing her to retire from exploration and become an instructor at Starfleet Academy.

External links[]