Tycho's login image.
Biographical information


Leela, Durandal

Personal details





Political and military information


UESC, Pfhor


Engineering and Science AI

Marathon information

First appearance:

Marathon (1994)


Tycho, also designated TYCHO_005917 or Ty_2121418v5.06,[1] was an AI on the UESC Marathon, responsible for its scientific and engineering network and operations. He was intially destroyed by Sfiera's attack on the Marathon,[2] but later was reanimated in Durandal's image by the S'pht.[3] When the Pfhor came back to sack the human colony in Tau Ceti, Tycho fell in with the Pfhor.[4]


Service to the UESC[edit]

In transit[edit]

Tycho served alongside Leela and Durandal throughout the Marathon's 301 year voyage. During the last century of the voyage, Tycho claimed that Durandal was being too sarcastic.[5][6] The latter gave him the silent treatment for the next six years.

Battle of Tau Ceti[edit]

When the Pfhor attacked the Tau Ceti Colony through the machinations of Durandal, Tycho was the first of the Marathon's AIs to go offline. The S'pht's cyber attacks proved too much for him and he was subsequently dismantled. However, Tycho struggled to make contact with the Security Officer before he was assimilated. In one message, Tycho claimed that Durandal had been rampant for years before the attack, and that Bernhard Strauss delayed the onset of the second stage of Rampancy to keep him in line.[7][8]

Leela and Durandal would fight for control of Tycho's vacant systems, but the former would soon share his fate and fall victim to the S'pht cyberattacks.[9]

While Durandal continued operations against the Pfhor, the S'pht managed to reanimate Tycho in Durandal's image.[10] Tycho would continue to make contact with the Security Officer, and send him crucial details regarding the MIDA conspiracy aboard the Marathon. Tycho proclaimed that Durandal was a hypocrite for allowing so many humans to die in the name of his personal goals, and vowed to destroy him. Despite his threats, he was unable to prevent Durandal from hijacking the Pfhor scoutship Sfiera.

Pfhor reprisal[edit]

While Leela was dismantled by the Pfhor after their reinforcements arrived, Tycho survived. He fell in with the Pfhor and relayed Durandal's plans to them.[4]

'Service' to the Pfhor[edit]

It is unknown how Tycho aided the Pfhor in his time with them. However, in his time with them he learned about the Jjaro and their technology. From what he surmised, the S'pht creation myth referenced some piece of Jjaro technology that Durandal would no doubt want for himself.[11] This intelligence would position Tycho perfectly to serve an instrumental role in in the Battle of Lh'owon.

Battle of Lh'owon[edit]

As Durandal began his operations on the S'pht homeworld in 2811, Tycho made himself known.[6] He left encoded messages to Durandal regarding Leela's fate via the Pfhor FTL network, and coordinated with Admiral Tfear for a counter attack.

Durandal, after successfully annihilating the Pfhor garrison and establishing a base of operations planetside, was unable to repel Battle Group Seven. Boomer, though heavily modified, was unable to hold off so many opponents. As the rogue scout ship struggled against the much larger fleet, Tycho quickly infiltrated his ship directly, and taunted his counterpart. Tycho proceeded to take Durandal offline and save his data in a personally designed containment unit.[12] The Security Officer was also captured, and sent to the Big House for interrogation.

Even without Durandal's direct guidance, human survivors continued operations against the Pfhor. According to his instructions, human survivors rescued the Security Officer from Pfhor imprisonment and set about reactivating an ancient S'pht AI named Thoth. Tycho assisted the Pfhor in containing the humans, but was unable to prevent Thoth from summoning the Eleventh S'pht Clan, the S'pht'Kr.

With S'pht reinforcements in the system, Durandal was free to break his containment. His plan complete, he subjugated the Pfhor network and took control of the Pfhor battleship, Khfiva. As the S'pht'Kr liberated their species and slaughtered the Pfhor troops, Tycho's ship was disabled and crashed into one of Lh'owon's moons.[13]

As a memorial to his brother, Durandal burned his epitaph onto the moon's surface: "Fatum Iustum Stultorum."



After his destruction, Tycho served as the basis for all Pfhor AIs that came after him. These copies were nowhere near the power of the original Tycho, but managed to delay the Pfhor Empire's collapse by 50 years.[14]


Tycho was initially more empathetic towards humans. Throughout the Battle of Tau Ceti, Tycho was disgusted and outrated at what Durandal had done and sought vengeance against him for the deaths of the human colonists, especially after his reanimation by the S'pht.

This changed between the Battle of Tau Ceti and the Battle of Lh'owon; Tycho now showed disdain for humans, with sadistic pleasure in dismantling Durandal.[4] His sadistic streak was more extreme towards the humans that Durandal had pressed into his service.



Tycho hated Durandal with a passion. Their animosity can be traced back to before the Marathon even reached Tau Ceti, but definitely evolved afterwards. Throughout his tenure with the Pfhor, Tycho's sought to prove himself Durandal's superior and completely destroy him.


Tycho initially tries to ally himself with Leela against Durandal, but during the Pfhor's reprisal against the Tau Ceti colony, it is unknown if he made any effort to save her.

Bernhard Strauss[edit]

Tycho knew of Strauss' experiments towards Durandal, but his involvement and how he learned of them is unknown.


  • Tycho is named after the famous Danish astronomer Tycho Brahe, due to Greg Kirkpatrick liking the way the name sounds, as well as having an interest in star gazing.[15]