I noticed this also. You must use space and esc buttons in campaign mode because if you press shift or ctrl, you won't be able to turn the ship or accelerate at the same time.
Its related to a key - jamming issue, in that thanks to certain keyboards (including mine, mores the pity) the current combination of keys doesn't work if more than one is hit at once. This generally means that you can't manouver and fire at the same time in the full game- are you having that problem? If so, it goes without saying that you're not going to be able to revolve the turret, because you have to use your 'special' button, as well as a movement key to make it happen.