ART was rotating through displays of all its data on the terraforming engines. It could "see" the engines by assembling a picture using the raw data from its scans, and it actually looked enough like a visual image to fool human vision, except that the topography around it was mostly extrapolated and sketched in. The amount of signal noise the engines were emitting blocked everything else out, so they were the only things the scan could pick up—this was the blackout zone the colonists had talked about. We could send in pathfinders but they wouldn’t be able to use their scans, either, so they would have to visually record and then return to a point where they could send ART their data. Barish-Estranza was trying to keep an eye on everything we did, obviously, but planets being large, that was impossible, just like it was impossible for us to know everything they were doing. If they did spot ART’s pathfinders entering the blackout zone, we could say we were gathering data on the status of the terraforming engines. But if we sent pathfinders into the blackout zone that then came out and delivered reports, and then we sent a shuttle in, that would tell B-E that we had found something worth looking at in person. Better to send a shuttle with the pathfinders, and log it as an evaluation of the terraforming engines.