Setting advice for a modern warship. Or a submarine, effectively... IN SPACE.
Another subgenre I’ve never tried (real-world military) and one I’ve just played a little (practical military SF) but which could be interesting. See also historical sailing, whether World War, Napoleonic or, this being RPGs, pirates.
Star Trek is mostly set on Starfleet ships, but those seem pretty casual and are definitely less cramped than modern subs. I’ve been in less roomy three-star hotels.
I included a bit of this (cramped minimal bunks, shift rotation, terrible food, playing cards as you wait to reach systems and fight) in my grimy military SF game The Stars On Fire, influenced by Battlestar Galactica 2004. Like the recent prison example, it let me build a smallish recurring cast... who might die at any time.