The CC never goes offline, it can work on 0 scientists, oddly.
Of course, your colony needs to never go below 4 scientists to be able to grow. 1 for CC, 1 for Nursery, 2 for University. Then, you should have more then that, in case one or two die while you're training more.
But I was just wondering what failure conditions they implemented on that map... could be they made launching a evac module a fail condition.