One of the fun things with my Rogue trader Campaign was that most of the players know the universe more then I do. Or do they?
Each of them read 80% of the warhammer 40K fiction and they are scientist/engineer minded guys.
Honestly it added a challenge so what I do is research, reading, and I bounce ideas off a non-PC also familiar with the System and story. So far this has enabled a more enjoyable time according to cannon.
There have been a few times that I was veering towards messing up but good news is I let the dice fall whee they may and the PCs enjoy that.
I also have indepth knowledge fro mthe first rigue trader but much of the fiction has changed since then.
Oh yeah...They maybe going on the great anti-Slaan crusade soon.