This is the most important question I need to answer to get the novel(s) can progress with any real momentum.
We know he is brave, resourceful, focused, and a skilled pilot, but none of these things give him sufficient drive to deliberately put himself in to a prejudiced position at the Academy. More importantly, they don’t provide enough drive to keep him there. Why wouldn’t he just give up?
If I move the attack on Starlight sequence to the beginning of the first book I, he could want revenge. Trouble is Mervyn isn’t a revengeful sort of guy.
He could want to be a Sled pilot, but why would that take him to the Space Academy. He could want to be Galactic Sledding champion, but again why the Academy?
I think he wants something else, but at the moment he’s not telling me. I’ll have to keep looking.