|Born:|| 17 March 2357
|Stationed:||Starbase 115; USS Yagami (NCC-78334)|
Officially, Irina Nielsen was the Chief Flight controller of the Sovereign-class starship USS Yagami. Unofficially, she was a member of the Omega Force, a highly-trained team of Starfleet officers whose primary mission is to handle cases involving the Omega molecule and other matters where a fully-crewed starship is inappropriate.
Irina was the first non-Romulan on record to receive the Hiren Cluster, the Romulan Empire's highest military medal, for her "conspicuous gallantry" in defending Romulan citizens and material from harm during the hostage crisis on Magor VI-B. (Destiny at Magor, Some Other World)
During her time at Starfleet Academy, Nielsen counted as her primary inspiration Demora Sulu, the third captain of the USS Enterprise-B. (Team Chipmunk: The Next Generation vs. Star Trek: Omega Force: "Beyond the Edge of Forever")
- Flight controller - Ensign, USS Voyager (NCC-74656) - 2377 - 2378
- Flight controller - Ensign, USS Titan (NCC-80102) - 2378 - 2380
- Flight controller - Lieutenant , USS Yagami (NCC-78334) - 2380 - present
Through photo manipulation, Lieutenant Nielsen is played by Olesya Rulin, the actress who played Kelsi Nielsen in the three films of Disney's High School Musical franchise. Elements of Rulin's life, such as her birth date (March 17) and birthplace (Moscow, Russia) were integrated into Irina's own background.
The reference to the Star Trek universe Kelsi Nielsen being Irina's great-grandmother was created to explain the usage of a photo of Olesya Rulin for both characters.