Catholic science fiction

Speaking of the Pope, what are your favorite Catholic science fiction books? I don’t mean just books written by Catholics, nor do I mean books where the Catholic church plays a plot role (like the Hyperion series), but books with a strong Catholic-related theme, like A Canticle for Leibowitz. Bonus points if canon law makes a strong showing there.

While we’re on the subject, forget about science-fiction. What about Catholic-themed novels generally? Bonus points, again, if canon law makes a strong showing.