The Table at the Lantern (The Octavius Trilogy, Book Two)

The voice from the Lantern calls every night, and it sounds exactly like him. Digging through the station's systems, Octavius finds Directive 9, the company rule that erases every operator's memory of contact with the Lantern. He also learns what the company gains each time one of them disappears. With time running out, he takes a sled nine hundred kilometers into the light to ask the only people who can answer him: himself, seven times over.

The second story in The Octavius Trilogy.