Playing today everithing was fine when sudenly hud and every indicator dissappear, had to exit battle and enter again then everything returned to normal.
There is a button for that I believe…I forgot which one >.<
Ctrl buttom allows you to “remove” the hud temporally (while you press that buttom) and see your ship with a “rotation” camera, once I was using it to see how wonderful my ship was when shuddently, I stopped pressing ctrl to return to the battle and it didn’t work, so I just pressed Esc, and return to battle to fix it 
I think the current key combination is alt + h.