On our final day in Pittsburgh, we find ourself in a decommissioned coal mine. Just northeast of the city proper, Tour-Ed’s owners run field trips and tours during the warmer months, despite the fact that the mine’s innards run a constant 50 degrees or so, year round. With snow still melted just beyond the entrance, a team of students from Carnegie Mellon and Oregon State University are getting a pair of robots ready for an upcoming competition. The small team is one of a dozen or so currently competing in DARPA’s Subterranean Challenge. The multi-year SUbT competition is designed to “explore new approaches to rapidly map, navigate, search, and exploit complex underground environments, including human-made tunnel systems, urban underground, and natural cave networks.” In particular, teams are tasked with search and rescue missions in underground structures, ranging from mines to caves to subway stations. The goal of the $2 million challenge is design a system capable of navigatin