Enceladus

Enceladus is Saturn's ice-moon and an Ordo Malleus palace-fort, not the Segmentum Pacificus world of the same name. Lord Inquisitors keep estates and forbidden Chaos libraries in the Encaladus Fortress, and Saturn's old rulers signed with the Emperor at the Admiralty Spire. The Sisters of the Order of the Shattered Glass also base here.