Our moon is kind of coincidental and there have been any number of theories as to why that is so. They range from the unlike to the inprobabable to the "it's time for your meds now".
Of course there are a few cultures who have stories of times when the moon either did not exist or went away for a bit and came back.
So....
I didn’t read Weber; however, I read something in my youth about one of the moons of Mars as an Arc. I just took some poetic license.