One of the big differences between running a fantasy campaign and a science fiction campaign is that when playing SF, I find myself constantly looking for starship deckplans.
With a fantasy campaign, many of the maps revolved around buildings, dungeons or overland adventures, and those sorts of maps were easy to knock out over lunch. Failing that, I had plenty of maps from 20+ years of Dungeons & Dragons that I could fall back on.
With my Star Wars campaign though, the adventures are split between world-based exploration and starship- or space station-based combat. Starship based adventures represent perhaps 1/8 to 1/4 of the encounters I run, but when I do run them I often find myself scrambling for deckplans.
The big reason there is that it takes more effort to come up with a rational-seeming starship. A dungeon can be as simple as a series of rooms, but with a starship players always want to know where to find the bridge, engineering, jeffries tubes, etc.