I would probably let the students pick and justify their selections and get a short list.
The history of science fiction goes back to H.P. Lovecraft's own book collection. I believe he was greatly influenced by, as were many young students who grew up to write the first Sci-fi back earlier in the 1600's - Robert Wittie's Star Wars - written specifically to stimulate the minds of students and open their eyes to the heavens.
The book in question was both a paper to the Royal Society - 'A Survey of the Heavens' a serious work with chapters such as 'The verification of the (recent) Copernican Hypothesis' to 'The Probability of Other Inhabited worlds'. At the end of the rare copy I own is the story 'Astromaxia' or 'Star Wars'. Lovecraft's copy is I believe at Yale. It also contains several things that might make you think of George Lucas's Star Wars plot, but I don't know if Lucas ever read it.
I find it quite grounding to realise that nearly 400 years ago sci-fi was alive and well.
I believe it is available on microfilm at some Universities but if you have difficulty I could perhaps provide you with a digital copy.
"This isn't brain surgery; it's just television." - David Letterman