Quadrotors have become affordable, ubiquitous platforms that can fly quickly over rugged terrain to collect critical data, but most small quadrotors can only stay in the air for tens of minutes at a time. Perching allows a quadrotor to shut down its motors and let its sensors acquire data over an extended period of time. Researchers from Stanford University’s Biomimetics & Dexterous Manipulation Lab have developed an opposed-grip strategy with micro-spines - hardened steel spikes on a special suspension - that enables quadcopters to perch on outdoor rough surfaces. This opposed-grip strategy works by dragging two sets of microspines along a surface in opposite directions. The spines catch against tiny bumps and pits on the surface and hang on using friction. Pulling the opposed sets of spines against each other produces a tight grip that lets the quadrotor land not only on vertical walls, but also on angled or overhanging surfaces.