Secret in the Library
With everything worked out, Callistratus leads you to the local aiudara. It does stay on all the time, of course, but there are set times when it is scheduled for activation so that people wanting to come from other parts of the planet or the other Pact worlds can use the portal there to come to Castroval.
"We know how the portals work but not why," Callistratus says to Le'Auil as they approach the aiudara. "We'd have no idea what time it might be on the Starhawk or where in the universe it might be after several trips through The Drift, but we know the addresses of all known aiudara and that is how we access them. Oddly, it doesn't seem to matter how far away another one is or where it is, the two connect and the portal is opened. However, they don't work into or out of The Drift, so usually it's the Captain that initiates the connection. He checks in periodically."
"We'll call up the one on the ship now, and you step through onto the ship. The mere fact of you stepping through tells Captain Zenith that we sent you, and if he has any crew wishing to return, they can step back here to Castroval."
"If you have any last minute questions, now's the time to ask them."
With that, the address is tapped into the aiudara's console, and a moment later, the portal is established.