On a National Treasure-eque journey that I am planning for my players, one of their points of travel will be Terra.
How can a Rogue Trader in a registered Slaughter-class Cruiser (registration done by Blood Ravens) get to Terra without being blown up?
To be more specific...they will be in orbit in the same exact spot that the Vengeful Spirit once held when the battle between the Emperor and Horus took place. So over the Imperial Palace...
Here, they will be met by an ancient space marine who will give them a piece of the puzzle they are trying to solve.
From there? The next impossibility...gain access to the Vengeful Spirit itself to open a secret compartment in the throne Horus once sat upon for the next piece...