Present during the Giza excavation in 1928 as a young girl, Catherine Langford's lifelong pursuit to uncover the mysteries of the Stargate brought her both joy and tragedy. It was her father, Professor Langford, who led a team of engineers in opening the gate in 1945 by random dialing. They believed the device to be a "doorway to Heaven," but were uncertain of its true function. At the time, the professor's co-worker Dr. Ernest Littlefield was very close to asking permission to marry Catherine -- but he was lost through the Stargate when they established a connection to another world, and was unable to dial home.
Catherine spent much of her adult life petitioning the U.S. government to reactivate research regarding the ancient artifact. Finally a team was created circa 1995, and Langford led a team of research scientists (including Drs. Samantha Carter, Barbara Shore, and Gary Meyers) inside a military installation at Creek Mountain. There the team worked to uncover the gate's true nature and functioning.
It was two years later when she discovered Dr. Daniel Jackson, an archaeologist shunned by the scientific community for his unorthodox theories. Landford hired him to analyze the symbols on the cover stone placed over the Stargate when the ancient Egyptians buried it. Two weeks later he found the answer, and Langford bore witness to the shimmering pool of the event horizon within the Stargate when it was activated for the first time in over 50 years.
The first mission was a success, and Langford retired to her home as the Stargate was decommissioned and transferred to the Cheyenne Mountain facility. Over a year later, Jackson, who had returned from Abydos, arrived at her doorstep to inform her that the Stargate had been reactivated -- and can go to many other worlds. Catherine was initially angry that he had kept the existence of the Stargate program from her, as the gate had been her life's work.
Jackson brought her back to the S.G.C., where she joined SG-1 in travelling to a world where they believed her lost love, Ernest, would be found. Catherine and Ernest returned to Earth together to live out their lives in happiness. She passed away some seven years later.
"Stargate" the Movie - Catherine's father leads the expedition that discovers the Stargate in Egypt in 1928, when she was a young girl. Decades later, she brings Daniel Jackson into her project to unlock its mysterious and activate the gate.
The Torment of Tantalus - Daniel reveals to Catherine that the S.G.C. continues to use the gate to explore other planets, and she joins SG-1 on a mission to recover her lost fiance, Ernest Littlefield -- who was lost through the gate in 1945, and presumed dead.
There But For the Grace of God - In an alternate universe, Catherine is a member of the S.G.C. She supports Daniel's efforts to return to his own universe with a warning about the coming Goa'uld invasion, even though it means the defeat of Earth in her own, and her own death.
1969 - Daniel and Sam -- in disguise -- visit Catherine in the year 1969, and find out the location of the Stargate so that SG-1 can return to their own time.
Moebius, Part 1 - Daniel receives word that Catherine has died, and gives a eulogy at her funeral. There he meets Catherine's niece Sabrina Gosling, who has her entire artifact collection delivered to him -- Daniel's inheritance from a woman who was like a mother to him.