>Real spaceships do not and will not have humans in the control loop except to specify a destination or target.

Jim Lovell would like a word.

That's how The Expanse generally worked, except when they needed to do things outside of normal circumstances.

Would dead-reckoning work or using some galactic sextant?

Yeah. Though they do have some nods towards realism, like how most combat systems are fully automated. PDCs fire automatically (at most they need a designated target, and for point defense they just fire), and even torpedos are assigned to targets using some touch screen and that's it, they are not fired using a joystick or similar nonsense.