Actually I was thinking of Macross II, not Robotech, with the ship "waking up" when the Marduk fleet dropped into the Earth System and firing off the main-cannon. . I don't actually recall Robotech implying that the ship was a sentient though, though it's been years since I've had anything to do with any Robotechish takes on Macross, so my memory is probably rusty on the finer details.