You know, just because a ship explodes into fiery debris, doesn't mean that the Hero dies...
They do have space suits after all. They might have a benevolent god that sees fit that the unlikely is made likely and they are picked up by a passing advanced scout of the Urka Tal, made a prisoner, only to escape/rescued later, after suffering some of the most heinous torture imaginable, and then lead a new fleet to victory...
I for one won't believe anyone in particular is dead unless/until I read about a body (but then, you might get around even that...) So maybe Sakazawa isn't out of the picture yet.
Just a thought.
Well done BTW.