Military drones are already used to survey the border between the US and Mexico, but starting last week, another piece of military technology has made its way back home. The latest surveillance tool to be picked up by the Department of Homeland Security is the Kestrel wide-area camera system, which can capture miles of terrain in a single high-resolution image. The system was originally used in Afghanistan, where it watched perimeters and took pictures of insurgents at bomb emplacements.

Mounted to a 75-foot aerostat 2,000 feet off the ground, the Kestrel was deployed last week to watch the border in Nogales, Arizona. There, the DHS reported that it allowed them to make a total of 80 arrests over the course of the week. "The coverage was amazing. We were able to see activities happening in different parts of the city all at the same time," a spokesperson reported. That doesn't mean, however, that the Department is going through all these images. John Applebee, who manages the DHS border camera program, told Wired that his team simply doesn't have enough people to analyze everything that the Kestrel picks up. In the long term, his team is looking for software that can prioritize images likely to contain "illegal intrusion."

There's relatively little controversy over watching the border, but it seems unlikely that law enforcement agencies won't at least consider using the Kestrel in other places. Like a massively powerful version of the NHK's balloon camera, it could theoretically be deployed at outdoor events or used in the same way as current police drones. At that point, we'll have to decide whether wide-area surveillance is simply an extension of current technologies or something that should be considered off-limits except in exceptional situations.