Sylvia Tilly

Sylvia Tilly was an ambitious female Human Starfleet officer who lived during the mid-23rd century. She served aboard the USS Discovery while still a cadet in 2256, later commissioned as an ensign.

Childhood
Tilly was born in 2233. She was raised by her mother Siobhan, but she was not around a lot. 

In 2242, when Tilly was nine, she worked out how to make her food synthesizer produce only spumoni ice cream by calculating the exact protein concentration and small particle dispersion of emulsifiers required. 

Tilly described her fourteen-year-old self as a weird kid, who didn't have a lot of friends and with no one who believed in her, including herself. That year, in 2247, Tilly attended Musk Junior High School for six months, where she befriended May Ahearn, who gave her the nickname "Stilly". She transferred schools when her mother got another posting. 

Tilly claimed to have gone through "a bit of a rebellious phase" when she was sixteen. 

In school, her mother remembered a particularly painful time when she had more trouble climbing a wall than the other children, where Tilly chose to run away rather than confront the challenge. 

USS Discovery
She rated herself as the best theoretical engineer at Starfleet Academy, and was fast-tracked in order to serve aboard the Discovery, where she served in engineering.

She initially had quarters of her own due to her "special needs", since she was allergic to polyester and viscoelastic polyurethane foam, which caused her to snore. 

The war
In November of 2256, she participated in her first away mission, investigating the crew's deaths aboard the USS Glenn. 

Although often socially awkward, Tilly came out of her shell in certain settings, such as the party held on Discovery, even showing aptitude at 20th century beer pong. During the event, Tilly rebuked romantic advances from Lieutenant Rhys. Paradoxically, Tilly also became a social mentor of sorts to Michael Burnham and facilitated her introduction to future romantic interest,. 

Post-war
In 2257, in recognition for her role in ending the, Tilly was awarded the Starfleet Medal of Honor. She received her officer's commission as an ensign and was placed on the command track. 

Tilly continued to serve on the Discovery, under the temporary command of Christopher Pike. She participated in the Command Training Program during this time. 

Later the same year, Tilly volunteered to stay on the Discovery and accompany Burnham when she took the ship forward in time to the 32nd century, with no chance to return. She recorded a farewell message to her mother before she embarked on the journey. 

Tilly, along with the rest of the volunteering Discovery crew, was presumed dead by Starfleet, based on the testimonies of the USS Enterprise (NCC-1701) senior staff. 

Michael Burnham
Upon meeting Michael Burnham, who at the time was an inmate being assigned to share quarters with Tilly temporarily, Tilly was delighted at the thought of having a roommate, stating "A roommate is like an automatic, built-in friend." While Tilly's offer of friendship was initially rebuked by a cold Burnham, and returned later in engineering, Tilly soon found herself admiring Burnham's courage. While still lacking confidence, Tilly shared her closely held dream with Burnham: that she would be a starship some day. Burnham, admiring Tilly's optimism, took her under her wing – often engaging in physical and dietary training together. 

Tilly kept a photograph of herself and Burnham in their quarters, next to both of their Starfleet Medals of Honor. 

Later, she volunteered to travel to the future with Burnham in Discovery despite not being able to return home. 

Paul Stamets
Tilly and Paul Stamets frequently worked together on the spore drive.

May Ahearn
Tilly met the real May Ahearn when she briefly attended Musk Junior High School in 2247. They frequently ate lunch together. Tilly never spoke to May again after her mother was transferred to another posting.

After being injured during an attempt to remove a piece of the dark matter asteroid, in 2257, Tilly started seeing a hallucination of Ahearn. After learning the real Ahearn had died in 2252, Tilly discovered the hallucination she was seeing was in fact of a species native to the mycelial network. 

Romance
Tilly indicated that she had, at various points, been interested in "musician"-types and "soldier"-types. 

Personal interests
Tilly had read everything there was available on Philippa Georgiou, and was exceptionally excited at the prospect of meeting her after her presumed death. 

Tilly enjoyed espresso with milk alternative, as well as ice cream. 

Memorable quotes
''"What the heck&hellip; heck&hellip; hell? What the hell! Hold your horses!" ''
 * - Tilly, attempting to impersonate Captain "$𝜇$"

Appearances

 * except:

Background information
Sylvia Tilly was portrayed by Mary Wiseman. The character was named after the young niece of Gretchen J. Berg. 

Apocrypha
Tilly is the focus of the novel The Way to the Stars. Her grandmother on her mother's side is revealed to be named Adèle, while Tilly's father is named Iain and serves as a lieutenant specializing in xenoarcheology on the science vessel Dorothy Garrod since a year before Tilly's sixteenth birthday. Tilly's mention in the episode "Project Daedalus" of having run away from home at age 16 and engaging in computer-hacking was very likely a direct reference to the events of this novel, which would have been written prior to the TV episode.

Tilly appears in the "Age of Discovery" expansion to Star Trek Online, voiced by Mary Wiseman. In the tutorial for Discovery-era player characters, set shortly after the Battle of the Binary Stars, Tilly is a third-year cadet at the Academy, whose engineering aptitude allowed her to be chosen as chief engineer for the cadet cruise aboard a vessel. When the player character, a fourth-year cadet, unexpectedly becomes the captain, Tilly remains as chief engineer until the ship returns to Earth after rescuing the miners of Corvan II, after which she parts ways with the player just before her eventual assignment to the Discovery.