Mandeville Point

Before a starship outfitted with an Imperial Warp-Drive can enter the Immaterium, it must first travel at sublight speed to a star system's so-called Mandeville Point. This is the closest distance that a voidship can safely enter or exit Warpspace from its origin or destination system, respectively. The origin of the name for this point is unknown, as it stretches back into the Age of Technology when Mankind's first interstellar civilisation developed the Warp-Drive, allowing humanity to achieve regular FTL travel.