The primary adventuring group centers around licensed troubleshooters on the frontiers that are legally empowered to taken on 'law enforcement / problem resolution' jobs.
However, it has something else going for it that makes it quite palatable for an Inquisitorial Seal-powered set of Lazers on a ship: the presence of Kenneth Hite's series of Hideous Creatures for Trail of Cthulhu (another GUMSHOE-powered RPG dealing with, er, Cthulhoid adventures).
Here are some initial suggestions that you may wish to look at:
- Hounds of Tindalos -- great for a near-encounter while transiting via Jumpgate! And then when they begin following you throughout the void by materializing in the corners of your ship -- or even on ground... I guess it just adds to the dangers of jumpgate travel. And perhaps that's the real reason for the Sathra dampers? Perhaps the minds of Sathraists have intersected in some way with those of the Hounds -- or their masters?
- Star Vampires -- an invisible creature whose horrible inhuman visage is slowly revealed by the splattering blood of victims that it feeds on? Perfect for a shadowy encounter on a planet -- perhaps in a town that has ceased to communicate with the main colony of the planet. And initial sorties that have gone to investigate haven't returned.
- Ghouls -- Lazers coming in, expecting to deal with a husk outbreak will be woefully unprepared for these cunning predators. Far more interesting is to introduce them in one of their aspects are denizens of the Dreamlands, and their hints as to how they've been able to colonize the stars via Jumpgates and human exploration. Is there, perhaps, an empire of space-faring ghouls beyond one of the Jumpgates? One shudders at the thought.