How many officers and of what range of rank should I include in the ships of my SciFi universe? I am trying to make my universe as scientifically realistic as I can (with the occasional exception). Ideally the ships in this military would be comparable to modern naval vessels in size, however I expect that a couple hundred years of automation would reduce the crew necessities greatly.
Traditional SciFi novels and movies seem to give off this idea that there are really only a handful of officers on ship. These officers are of course headed by THE CAPTAIN, with a handful of commanders and lieutenants in tow. This kind of contradicts the fact that some quick google searches show that modern Aircraft carriers usually have a couple thousand officers and multiple at the rank of Captain or equivalent (with of course a single officer acting as the CO).
As modern space missions can only support half a dozen or so individuals at a time, I am hoping to strike some sort of balance. I want ships to have a realistic crew capacity, but not so many that I have a few thousand completely forgotten officers. Obviously There should be an officer for each major command position, and probably 2 additional officers each to relieve them. I want to make it as few as possible, and I imagine that different classes of ship would of course have different requirements (i.e. carriers need way more command staff than a destroyer or a frigate).