For a while I thought his might just be a geocentric model that doesn't hold much real meaning and was just there to kinda suit the time period. Then again, the OL was considered so dangerous for its knowledge, and with actual space-people involved capable of space travel(to some extent)you'd assume they know how the solar system is structured, or at least how it was before whatever happened, happened.
I think that there were multiple moons that were destroyed during the void century, forcing some of the inhabitants to flee to earth. Hence, why you have so many different species to begin with.
That being said, It's very hard to tell since other than that model there's no real evidence to indicate that there was ever more than one moon. And as I said, that model might just be a nod to the time period, hence, completely insignificant.
