Cramped crawl spaces, virtually all starships have them, and usually most players ignore them. Unless a nasty alien gets loose inside the ship, even many Gms don't give them a second thought..
Here are 30 other issues that could require some crawl space access and provide an interesting sub plot.
The Water-Rift is a massive crater in the center of the desert, in the center of which sits a large, unfathomable machine that produces water. Thusly, it is a veritable paradise in the center of the burning desert, and a unique culture exists there.