Suffering from repeated Wraith Cullings for thousands of years, Jamus' people came up with a desperate plan where they would save around 2,000 of their people while making the Wraith believe they were extinct and would thus never return. To this end, five generations of Jamus' people worked on hollowing out a moon and turning it into a Moon Base capable of acting as an ark for their people. Jamus' people were able to get their hands of a Wraith beaming device, presumably from a crashed Wraith Dart and reverse-engineer it into two pattern storage modules that could each hold around a thousand people. The engineers were also able to modify the devices to hold the patterns indefinitely without degradation, something the Wraith version lacked. (SGA: "The Ark")