Basically, it's an analogy, and I've spent perhaps too much time trying to make it work, when it really doesn't stretch that far. But, as with any analogy, it works fine within the limits of what it is supposed to cover, so long as you know where those limits are and why they won't stretch further. You, analogy. That thing.
I've made the analogy more specific for my grade 12s, linking their June exams with Apollo 9 (a chance to see how they'd cope with all the necessary elements of the final exam, but in a safer, more familiar context), the prelims with Apollo 10 (a full-scale dress rehearsal of nearly every aspect of the final goal), and final exams as Apollo 11 (the big thing).
And then, just like post-Apollo NASA, you face the uncertainty of what to do next. Do you build sensible space stations? Move to Mars? Figure out how to work internationally with other programs? Abandon space and stay home with your parents for another century? It's a great luxury to have a choice like that, and also terrifying.