The hub had a table in it: a broad steel surface between two of the consoles, scratched, bolted to the floor. Mara cleared it of dust with her glove and laid two sheets on it.
The first was Eshel’s printout of Sable’s survey, the cache from the last eleven hours, the columns and the signs, run off on the Tern’s small field printer and brought across the docking ring in a sleeve. The second was the lamp diagram. The Tern carried a set of them in its chart drawer, standard diagrams of a lamp’s outlet, its channels and its sensors, the way any guild ship carried diagrams of the things it might have to work on.
She laid the survey over the diagram, aligned at the corners. The paper was thin enough that the diagram’s lines showed through.
Then she compared them. Line by line. The survey’s sensor positions against the diagram’s. The survey’s channels against the diagram’s. The flow directions.
For a long stretch they agreed. Sensor 1, sensor 2, the main channel, the pressure taps. Then they disagreed.
At sensor 3. The outlet flow sensor. The diagram showed it facing inward, toward the lattice, measuring draw. The survey’s figures, read with their sign, showed it measuring flow going the other way. Outward.
