So Durandal knew about the S'Pht legend of the moon that warped out using folded space, and according to Tycho this reference started his journey to L'howon. To begin that journey, Durandal had to summon the Pfhor ship Sfiera to attack the Marathon, make a deal with the S'Pht compilers on board, take over the ship and gallivant about the galaxy. So Durandal would have to know about the S'Pht legend before summoning the Pfhor.
Could Bernard Strauss, the Marathon's first science director, have been aware of the S'Pht and their legends? Humans have had contact with the Jjaro in 1996 (Pathways into Darkness) and battleroids are heavily implied to use poorly-understood Jjaro technology (from Marathon Infinity's ending screen). It's not a far stretch to assume that a clan of S'Pht visited Sol at some point prior to being enslaved by the Pfhor and left documented evidence of their visit on Earth or perhaps Mars containing references to their old myths, later translated in secret. Marathon's science director (and very probable MIDA activist) Strauss might well have known about it, and as Marathon's science director he'd be the one to scour Tau Ceti for any alien technology that he could use.
I'd say it's likely that Durandal came to know about the legend through Strauss rather than through the S'Pht compilers during the attack on the Marathon - the entire purpose of the attack seems awry without Durandal knowing that the S'Pht could be very useful to him. Strauss and Durandal together are privy to some pretty big secrets such as Durandal's rampancy, their dirtywork on Mars, and bringing ten Mjolnir cyborgs aboard the Marathon in complete secrecy, so it's likely that Durandal had foreknowledge of the S'Pht.
Strauss's endgame may have been to find that moon-warping technology and use the Marathon to bring it back to Mars, and then warp Mars out to another, habitable solar system with more resources and no Earth to worry about. The ten cyborgs were probably in place to take over the Marathon when this technology was secure, not to mention deal with unwanted trouble from aliens. Of course, Strauss couldn't have foreseen a rampant Durandal taking over the plan by calling the Pfhor in early and hunting for L'howon for his own rampant ends.
