|Full Name:||Tobin Dax|
|Previous Assignment:||Cochrane Institute of Alpha Centauri|
|Final Assignment:||Chief Engineer, USS Pioneer|
In the mid-22nd century, Tobin Dax was recruited by the Cochrane Institute of Alpha Centauri to participate in the testing of a prototype transporter. (DS9 - The Lives of Dax short story: "Dead Man's Hand")
In 2157, Dax, Underhill, and Skon were present at a failed test of countermeasures to the Romulan remote-hijack system. Dax and Underhill participated in a successful test later that day after Skon had been removed for being a security risk. (ENT - The Romulan War novel: To Brave the Storm)
Spoiler warning: Plot and/or ending details follow.
Following the war Dax worked on several conceptual designs for what unified Starfleet vessels would look like. Dax felt that Earth's starship designs were the most logical for a fleet of exploration, and believed that even with the combined technologies of the Federation members the ships would look largely like Earth ships such as the NX class, Columbia class or the Intrepid class.
In 2163, Dax requested a posting on the USS Pioneer after he was asked to consult with the chief engineer following the installation of an upgraded warp core, one capable of sending the Intrepid class up to warp 5.6. He was assigned as chief engineer after Alan Sheehan was forced to undertake a leave of absence for medical reasons.
While on the Pioneer, Dax's joined nature was discovered by the ships doctor, Therese Liao. At the time the joined nature of the Trill was not widely known, and Liao respected Dax's wishes to keep that nature a secret. She did suggest to Dax that he confide in Captain Reed, which he eventually did. Reed also kept Dax's nature secret. (ENT - Rise of the Federation novel: A Choice of Futures)
In 2165, the Ware attacked the Pioneer, severely damaging her. His second-in-command Lieutenant Prentis Morrow died in the encounter, which reminded him how dangerous space travel can be, and decided to leave Pioneer. He visited his friends, Skon and T'Rama , on Vulcan, who invited him to stay in their home as a quest, until he decides where he wants to go. While there Tobin met Iloja of Prim, the exiled Cardassian author, who was also a stayed there. (DS9 episode: "Destiny")
During his stay, Tobin often visited debate houses with his friends, and followed the events of the unfolding political situation following the claim that the Kir'Shara is a forgery created by Earth Starfleet to overthrow the Vulcan High Command. He was also instrumental at preventing the destruction of Vulcan Space Central by the sabotage of the USS Endeavour's warp engine.
Although shy, Tobin enjoyed magic tricks. During the Earth-Romulan War, he demonstrated his abilities to Skon, who was not particularly impressed. (DS9 - The Lives of Dax short story: "Dead Man's Hand") However, they eventually became good friends. (ENT - The Romulan War novel: To Brave the Storm, ENT - Rise of the Federation novel: A Choice of Futures)