Conceived almost four hundred years before the events of Marathon, the UESC Marathon is a sizable space station that was converted from Deimos, one of the moons of Mars. Preceded by three years of preparation, the construction project which created the Marathon was officially commenced by the Unified Earth Space Council in 2408, and the endeavor spanned more than sixty years before its eventual completion. During this time, the humans' Mars colony, which had at the project's outset been a prosperous settlement, slowly deteriorated, stricken by poverty and famine due to a number of circumstances. Chief among these was the breakdown of the CRISTs (Cargo and Resources In-System Transports), which the colony had relied upon to support its population. Each time a CRIST would be brought back to Earth for needed refitting, a process which takes fifteen years to complete, the economic impact on the Mars colony was dire. Many Mars colonists requested as a result that the Marathon be used as a CRIST in order to help stabilize the colony, though the UESC ultimately rejected this idea. As the situation on Mars continued to degrade, the Marathon project came to be viewed as physical evidence of Earth's disregard for Mars' plight and the fate of its citizens.
After being commissioned in 2472, the original crew of the Marathon consisted of 50 senior staff, 1,150 officers, and 24,000 civilians culled from the population of both Earth and Mars. A number of the ship's more important passengers were placed in stasis, to be awoken only after the Marathon's maiden 300-year voyage had completed, though for most crew members the Marathon was their home during this period, the place where they both lived, worked, and raised their children. In fact, by the time the ship's destination was reached, a significant portion of the crew composition had lived the entirety of their lives aboard the station. Such crewmen were often derisively referred to as "bobs," short for "born on board." In the latter half of the 28th century, 2773 to be exact, the Marathon arrived at its intended destination in the Tau Ceti system, and over the coming years its crew established a colony there.
In addition to its human crew, the Marathon was aided during its active years by three separate A.I. constructs. These A.I.s were specialized in purpose, with each being assigned to manage well-defined tasks throughout the ship. Due to the Pfhor attacks on the station in the last decade of the 28th century, all three of the ship's A.I.s were either forcibly or voluntarily removed from the Marathon.
- Leela - The Ship Operations A.I. aboard the Marathon, Leela was in charge of most of the ship's critical functions, including defensive measures. She was the only A.I. that appeared to be fully functional after the initial Pfhor assault, and she lent valuable assistance to the security officer in his defense of the ship. Leela was dismantled and removed from the Marathon during the second wave of the Pfhor invasion.
- Durandal - Assigned to monitor and ensure the proper functionality of the ship's automated functions, Durandal was under the direct control of science officer Bernard Strauss up until the Pfhor attacks commenced. From this point onward, he bega to display signs of rampancy, and though he also helps the security officer, after repelling the initial assault, he utilizes a Pfhor vessel in order to leave the system.
- Tycho - Charged with overseeing the computer networks for science and engineering aboard the UESC Marathon, Tycho is quickly disabled during the Tau Ceti offensive. The Pfhor eventually succeed in extracting him from the Marathon, and, using Durandal as a model for his recreation, he is assimilate by them for use as one of their own A.I.s, later helping to pursue Durandal, who escaped the Marathon.
First Attack on the Marathon
Though colonization efforts in the Tau Ceti system were successful for a time, the UESC Marathon and its adjacent planetary colony would come under direct threat in 2794 when the Pfhor, a previously unknown race of alien slavers, warped into the system and, without warning, attacked both human footholds within it. Though Tycho was unable to offer assistance, both Leela and Durandal were critical in defending the station against the Pfhor, as was the security officer. In truth, however, the Pfhor were not thwarted by the Marathon's innate defensive capabilities, but rather by their own servants, the S'pht. Durandal had been in contact with the S'pht throughout the attacks, and learned not only that they were actively coerced into the Pfhor's service, but also that a single cyborg being was responsible for controlling them. Using this information, the station's defenders were able to turn the S'pht against their masters, leaving the Pfhor with little choice but to abandon their attacks. The crew of the Marathon sustained heavy casualties before the fighting stopped, but due to nine Mjolnir Mark IV cyborgs hidden amongst the colony's inhabitants, the humans planetside suffered far fewer losses.
Second Attack on the Marathon
Three months after being rebuffed by the Tau Ceti colonists, the Pfhor returned in force to renew their offensive. Aside from the few human colonists Durandal had abducted and taken with him following the first attack, every remaining human from the Tau Ceti colony was slaughtered in this second assault, including the nine Mjolnir Mark IV cyborgs that had proven to be instrumental in curtailing casualties during first contact. The Marathon itself is left with no human inhabitants and no A.I. systems, and with no other human presence within a 300-year journey of Tau Ceti, it can reasonably be assumed that the Marathon is lost to humanity.