If a human civilization beyond Earth ever comes into being, this will be unprecedented in any historical context we might care to invoke—unprecedented in recorded history, unprecedented in human history, unprecedented in terrestrial history, and so on. There have been many human civilizations, but all of these civilizations have arisen and developed on the surface of Earth, so that a civilization that arises or develops away from the surface of Earth would be unprecedented and in this sense absolutely novel even if the institutional structure of a spacefaring civilization were the same as the institutional structure of every civilization that has existed on Earth. For this civilizational novelty, some human novelty is a prerequisite, and this human novelty will be expressed in the mythology that motivates and sustains a spacefaring civilization.
A deep dive into deep time:
Record-keeping technologies introduce an asymmetry into history. First language, then written language, then printed books, and so and so forth. Should human history extend as far into the deep future as it now extends into the deep past, the documentary evidence of past beliefs will be a daunting archive, but in an archive so vast there would be a superfluity of resources to trace the development of human mythologies in a way that we cannot now trace them in our past. We are today creating that archive by inventing the technologies that allow us to preserve an ever-greater proportion of our activities in a way that can be transmitted to our posterity.