In the years following the destruction of their homeworld, humanity has what, conservatively, one could call a cultural good cry. There is no way to get a full figure of how much of Terra’s information wealth is lost, either to the nuclear destruction of the world or to simple mistakes made in a fog of grief. The bear species in part owes its “lost generation” status to this period of angst and loss and paperwork confusion. And the movement to push humanity into the background gained strength against an enemy in disorder.
As a game note, this period is often used to fudge any questions about what sort of information made it to Mars: limited communication and a lot of tragic chaos leads to a period of missing records and spotty, tear-stained notes.
Reference: Suggested from interviews with game author
Date Notes: Since the “end of life on terra” is only technically a hard date, humanity’s dark age may be a period that grows as the bombs continue to fall.