The Renaissance Project
This is a level three technology created by the Tolaris corporation. It is unknown how it works but it is designed to terraform a planet, whether or not it has ever successfuly been used is up for debate. Currently three organizations know of its existence and seek to obtain it: The Sons of Tolaris, the New Earth Heralds and the Preservation League.
According to the Preservation League the device was used once before, on earth, sometime after the nanotech virus of 2050. The first use was carefully controlled and a “library” of life was kept in a separate facility as a backup measure in case the device did not repopulate everything but this time around the technology to properly control it and shelter from it’s effects is no longer available. The vaults as they currently stand are no longer in sufficient shape to protect people from the fiery scourge before the terraforming and there are too many people not in vaults who wouldn’t fit anyway even if the vaults could offer adequate protection.