Shannon O'Donnell was an ancestor of Kathryn Janeway's and her greatest inspiration for joining Starfleet. She was also a consulting engineer on the Millennium Gate project that was completed in 2012 in Portage Creek, Indiana on Earth.
Shannon was an aerospace engineer and trained to be an astronaut with NASA. Her class came up with the slogan "Next stop... Mars" which was used by NASA's media department. Unfortunately she did not make it through the training program.
After leaving NASA, O'Donnell worked in the aerospace industry but eventually lost her job. She found herself unemployed and homeless and began traveling extensively, keeping a personal log by means of a small tape recorder as she did. It was during this time that she made plans to visit a cousin of hers in Florida. Midway through her journey she found herself stranded when her car broke down in the small town of Portage Creek in Indiana where she met Henry Janeway.
Janeway was a resident of Portage Creek, the future home of the Millennium Gate, and owned a little bookstore, Alexandria Books. O'Donnell met Janeway in his bookstore which was the only store in town that had not closed in order to make way for construction of the immense project. Both Henry Janeway, and his son, Jason Janeway, were initially suspicious of O'Donnell but welcomed her nonetheless and he even offered her a place to stay until her car was fixed.
The next day Shannon and Jason watched in front of the bookstore as Henry argued with Gerald Moss, who was being interviewed by Marci Collins of 3 Action News. The next day, as O'Donnell sat in a local bar planning her departure, Moss approached her.
Moss, who had worked at NASA at the same time as O'Donnell, told her that a classmate of hers made it into to the space program and was scheduled for four months of duty on the space station. Moss offered O'Donnell a job as a consulting engineer on the Millennium Gate project if she managed to convince Henry Janeway to give up his bookstore.
Because O'Donnell genuinely believed in some aspects of the project, she made several attempts to convince the classical-leaning Janeway to sell his store. Despite a mutual attraction, Janeway's resistance remained. Even though she failed to convince him to sell, Moss told her the project could still use her on the alternate building site of the Millennium Gate in Canton, Ohio.
When leaving town, O'Donnell realized that she did not want to leave Janeway and returned the same night. She talked to him and Janeway decided that he might re-open his bookstore in the Millennium Gate. Just before midnight December 31, 2000, Shannon and Henry left the Alexandria Books bookstore which closed for the last time.
Eventually, Shannon O'Donnell married Henry Janeway and together they had several children and grandchildren and lived in Indiana. Unknown to her, she would be an inspiration for a distant relative fifteen generations later: Kathryn Janeway, who up until then had believed that O'Donnell was instrumental in building the Millennium Gate and an astronaut in the early Mars projects. When she - with the help of Seven of Nine and Neelix - discovered that Shannon's role in these events and who she was differed vastly from what she had believed all her life, she was disappointed. However, Seven and others reminded her that historic facts were irrelevant as Shannon was an inspiration for Janeway to pursue her dreams and therefore an important part of her history. (VOY: "11:59")
Shannon O'Donnell was played by Kate Mulgrew.
In the novels The Rise and Fall of Khan Noonien Singh, Volume 1 and Volume 2, Shannon O'Donnell works at Area 51 (aka the Groom Lake Facility) under the supervision of Jeff Carlson. She is described as "on loan" from NASA. After being contacted by Roberta Lincoln, she helps to create, and later steal, the first Template:ShipClass spacecraft.