With a flat success you'd know the basics of what space hulks are, what likely xenos threats can be found on them, odd interior conditions and so on. Are you familiar enough with these or do you need me to give a quick summary?<br/><br/>http://warhammer40k.wikia.com/wiki/Space_Hulk covers the bare bones.<br/><br/>You'd have heard the name of the Harbinger of Desolation mentioned, but wouldn't know more than it's been popping up in the reach for the last few centuries, moving from system to system as hulks do, with little apparent rhyme or reason to the path.