Just reporting my findings. In Frontier First Encounters, which John Jordan converted to i386 (reference JJ-386 ship), the first Thargoid mission has you go to Turners Requiem on Fortress Culloden, on Alioth. Here you have to donate the max amount of credits before you are given a mission to locate the wrecked Turner's Quest. The Turner's Quest was Mic Turner's ship. A revolution in ship design, the Turner Class ship was the result of several years of intense R&D at the AAAI shipyards. Argent Aerodynamics Amalgamated Inc, or AAAI is a company co owned by Mic Turner and Meredith Argent. When the Alioth System decided to rise up against both the Federation and Empire, it had no navy, nor the means to build one. Meredith Argent and Mic Turner banded together and came up with the brilliant idea of retro fitting Long Range Cruisers into battleships instead of building a brand new navy. The people of Alioth volunteered their time and their own ships for the cause and AAAI was formed to manufacture the new Alliance Navy.
The Turner's Quest carries the largest and most powerful commercial hyperdrive known to humanity - the Class 4 Military. The drives range was over ninety light-years. Only four of these ships were ever produced; for the founders of AAAI, Mic Turner and Meredith Argent, and their close friends. The first Turner class ship, the Turner's Quest, is destroyed in battle with INRA in 3253. The second, Argent's Quest travels beyond the rim of known space, while the remaining two enter private service.
INRA had secrets beyond the northern frontier, namely how they won the war against the Thargoids. These were secrets they were prepared to kill to protect, which they did, destroying the Turners' Quest. When Mic Turner didn't make contact with AAAI, Jo Merion was sent to find out what happened. She recovered his Stowmaster Capsule but was then apprehended by INRA forces. She was eventually released without the capsule and given accolades with both major governments.
Undeterred, and worried for her friend, Meredith Argent hired a commander to fly the Argent's Quest (which I believe to be the first Thargoid mission mentioned above) to the last known location of the Turner's Quest (Pleione 4B). The pilot found the wrecked ship, including its black box and a wounded Thargoid ship (HIP 17125 A 3 A, anyone? Less than 40LY away from Pleione and the Turner's Quest drive could easily do 90LY). Returning to AAAI, the data was replayed and the commander sent to Polaris where there was reference to another unknown entity. The Argent's Quest docked with the entity and appeared in a system over 600 light years away - the Thargoid home planet. There, the commander learned that INRA developed a virus to destroy the Thargoid's organic hyper-drives. The Argent's Quest returned to human space to find the antidote. He returned to the Thargoid Homeworld with the antidote, allowing the Thargoids to travel again. In thanks they built a Thargoid warship for the commander, who flew home to accolades in the Alliance, but criminal charges in both the major powers, both of which are linked to INRA.