To understand and predict Earth-surface dynamics, scientists often rely on access to the latest remote sensing data. Over the past several decades, considerable progress has been made in the development of specialized Earth observation sensors for measuring a wide range of processes and features. Comparatively little progress has been made, however, in the development of new platforms upon which these sensors can be deployed. Conventional platforms are still almost exclusively restricted to piloted aircraft and satellites. For many Earth science research questions and applications these platforms do not yet have the resolution or operational flexibility to provide answers affordably. The most effective remote sensing data match the spatiotemporal scale of the process or feature of interest. An emerging technology comprising unmanned aircraft systems (UAS), also known as unmanned aerial vehicles (UAV), is poised to offer a viable alternative to conventional platforms for acquiring high-resolution remote sensing data with increased operational flexibility, lower cost, and greater versatility (Figure 1).