Colony Ship U.E.F London
In the year 628 AFL the WayCorp scout Expedition 1523 on system designated AV-312 (now known as the London System uncovered the remains of the human generation ship Colony Ship U.E.F London which landed on the 3rd planet of the system with all its crew dead.
This became the unrefutted proof that humans were sent to seed the galaxy on very similar colony ships (Similar to U.E.F Paris)
The discovery of the ship was a watershed moment for Humanity and many of the religious and philosophical cults like the Cult of Helios of The Reach
Ooh a mystery!