- This page details Irina Galliulin in the primary universe; for the Irina Galliulin in the Kelvin timeline created by Nero's temporal incursion see Irina Galliulin (Kelvin timeline).
Galliulin attended Starfleet Academy, and while at the school she entered into a relationship with fellow Russian Pavel Chekov, who was also attending the Academy. She was unable to adapt to the structure imposed by the Academy, and eventually she dropped out of the academy and broke off her relationship with Chekov.
In 2269, Galliulin and several other individuals stole the space cruiser Aurora. They were intercepted by the USS Enterprise. The Enterprise locked her tractor beam on the Aurora. When they tried to escape, they overheated the Aurora's engines, and had to be beamed off the ship before it exploded. Because one of Galliulin's accomplices - Tongo Rad - was the son of a Federation ambassador she and the others, led by a Dr. Sevrin were not charged with any crimes.
Eventually, with Spock's assistance, the group thought they found Eden, but the planet turned out to not be the place when it was revealed that all the plant life was filled with acid that caused second degree burns when touched. In addition, all the fruit on the planet was highly poisonous, and Sevrin committed suicide. Galliulin and the survivors were taken to a starbase, where she was urged by Spock to continue searching for Eden. (TOS episode: "The Way to Eden")
Afterwards, Chekov took a leave of absence from Starfleet to try to rekindle his relationship with Galliulin. However, things did not work well, and Chekov returned to the Enterprise. (TOS novel: Ex Machina)
The two managed to rekindle their relationship, and by 2293 had considered marriage. However, Chekov believed Galliulin thought he would return to her after he after he left the USS Enterprise-A. In actuality, Galliulin began a relationship with someone else and moved to one of the twelve planets in the Rigel system, telling Chekov she hoped they would remain friends even though she had broken off their relationship.(TOS novelizations: Star Trek VI: The Undiscovered Country, Generations)