The Colony Goes Dark

After the Security Officer and Durandal departed, the Pfhor returned to Tau Ceti in force. They destroyed the Marathon and the entire colony. But that was only the beginning of Tau Ceti's troubles.

The UESC began drafting a response: Project Goliath. The nature and composition of this rescue mission changed constantly due to backroom politics. At various points it was planned as a single assistance ship, a full invasion fleet, or a response to up to eleven different cases of AI rampancy (the colony had three AIs on the Marathon and eight planetside).

Tycho states that the Pfhor returned to Tau Ceti three months later and nuked the entire colony to bedrock, including the nine cyborgs in it.

Tycho states that, just like the Security Officer, the other cyborgs were "translated to Pfhor slave tanks", though not all of them survived that process, which implies that the colony was not nuked to bedrock in that timeline.