Once Upon a Fact

"Once upon a time" is a magical phrase; an incantation that conjures stories into being and gives them life. What we now call "fairy tales" outlived their original creators, outlasted their descendants, and one day might very well survive the death of our species. When, and if, humanity leaves this planet, fairy tales will make the journey too -- into the far-flung reaches of the galaxy and into the distant dimension of the future.
How different will the fairy tales of the future be from the stories told around hearth fires a thousand years ago? I suspect they will be utterly different and yet completely familiar.