Each bot in the swarm weighs in at just over an ounce. Credit: TU Delft / MAVLab

In 2008, a fire ripped through the architectural building at Delft University of Technology (TU Delft) in the Netherlands. Firefighters got the burn under control, but afterward, the school wanted to know if any furniture was salvageable.

So Guido de Croon, an associate professor of aerospace engineering, flew a drone around the building to survey the damage. But he didn’t want to get too close; de Croon worr