Sci-Fi, Fantasy and the Beadsqueezer.
Interesting interview with Sandra Miesel, Catholic blogdom's conduit to the wonderful world of science fiction and fantasy. She has some useful recommendations for those interested in enduring "classics":
For examples of what SF writers themselves think "classic," track down the SFWA Hall of Fame anthologies or the SFWA Grand Master anthologies. The reprinted Andre Norton novels that I mentioned above are from the ‘50s and ‘60s, but new readers still enjoy them because of their good basic storytelling. For specific books, the works of J.R.R. Tolkien and maybe C.S. Lewis’s Narnia series will be read for generations but those are special cases. Two good bets within our genre would be The Martian Chronicles (1950) by Ray Bradbury and A Canticle for Leibowitz (1960) by Walter M. Miller, which have both already shown great staying power. What complicates the picture (besides technological innovation and shifts in popular taste) is the SF & F field’s own transformation after Star Wars (1977) from a niche market to a huge, conglomerate-owned, bestseller-driven genre where half the books published are media spinoffs. It’s harder for the reader to find what’s genuinely good and harder for the writer to be genuinely original.
I think I've already given you marching orders on Canticle. It belongs in your library, class. I certainly hope you are prepared to give your report. As to explicit or implicitly Catholic/Christian works, she also offers up some advice:
Philip K. Dick, who was drawn to Oriental mysticism, shows "small folk" resisting evil and creating beauty in The Man in the High Castle, Three Stigmata of Palmer Eldrich, and Ubik. (I don’t recommend what he wrote post-1971!)
Poul Anderson’s explorations of the imperfectability of man in a universe doomed by entropy made him the master of the SF & F novelette. He celebrates freedom, courage, and responsibility in dozens of story collections, any of which will have some good stories. His fantasy classics Three Hearts and Three Lions and A Midsummer's Tempest have a Christian framework but The Broken Sword's is Norse paganism.
Gordon R. Dickson thought that man was perfectible but Pilgrim and Soldier, Ask Not are powerful tributes to faith, courage, and sacrificial love.
You didn’t ask about Christian writers but I’ll list some fine ones from former times anyway.
R.A. Lafferty wore his conservative Catholicism on his sleeve in Past Master, Fourth Mansions, and The Flame Is Green. His quirky short stories are like tall tales. Russell Kirk’s excellent ghost stories are collected in Ancestral Shadows. Manly Wade Wellman’s fantasy stories about Appalachia collected in John the Balladeer and Valley So Low presuppose Southern Protestantism. The SF collections The Rediscovery of Man by Cordwainer Smith, an Anglican, is overtly Christian and Ingathering by Zenna Henderson, a Methodist, is implicitly so. At the Young Adult level, try Elizabeth Goudge‘s Little White Horse and Linnets and Valerians which are exquisite fantasies suffused with Anglican sensibility. The Satanic Mill by Otfried Preusler is a vivid historical fantasy with a Protestant background.
The good thing about this list is that I can assure you it's not polluted by heavy-handed didacticism or preachifying. Sandra (let's be informal) hates that with an absolute passion. Ask her about a writer I happen to like--Michael D. O'Brien, and she'll discharge both barrels into the guy.
I can concur in at least one of the recommendations from personal experience. If you have not read The Man In The High Castle, please take the following in the nicest possible way: you are an utter, complete, pathetic drooling loser. Leave your office and home now, and go buy a copy (I assure you, the cover is an artsy irrelevance--the plot has nothing to do with iridescent torsos). As she says, it is a beautiful story about ordinary people trying to thwart great evil as best they can.
Do Androids Dream Of Electric Sheep? is another classic, which inspired the film Blade Runner, also a classic, but the two differ greatly in story, tone and focus.
With that, I'll chuck out a few more of my own recommendations: The High Crusade by Anderson, an absolute hoot where 14th Century English soldiers preparing to smash the French turn the tables on invading aliens.
--Anything by Katherine Kurtz set in the Deryni universe, which supposes a psychically gifted race called the Deryni trying to survive in a fractious kingdom suffused with medieval Catholicism, with all its glories and flaws. A note--her earlier stuff is a bit uneven in writing quality, to be blunt, and a bit uneven in the depiction of the powers of the Deryni (some display extreme powers like weather control, which are fortunately dropped as being a bit over the top, and never discussed again). But the later works have really rounded into shape, and can be a bit grim in spots (she is not afraid to let heroes die and evil triumph, even for an entire trilogy). Do not overlook the Deryni Archives short story collection, which includes the haunting "The Priesting of Arilan," a powerful story about the discovery of an attempt to pervert the Eucharist for evil purposes, indeed.