SJE said:
But we are not just talking about the Rogue Trader, but getting all the PC’s involved – how many heroic stories are there in the 40Kverse of the blind Astropath leading the charge of the Light Brigade or of the Navigator duelling the Necron Pharon in single combat?
In the case of the Astropath, they'll be there anyway. There's a long history of Astropaths on the front lines, simply because having high-speed efficient communication with, say, orbiting ships, is a considerable asset.
SJE said:
For Rogue Traders, there's a lot of importance placed on prestige and reputation. You don't hear about cowardly or unfit Rogue Traders primarily because they don't have the means or the will to do what's necessary to gain prestige and acquire a significant reputation.
SJE said:
No, providing that motivation, then making them regret it, and yet having them still wanting to go back and try again later... that's the art of the GM.