The National Oceanic and Atmospheric Administration (NOAA), with the aid of the National Aeronautics and Space Administration (NASA), is procuring the next generation of geostationary weather satellites. This book assesses progress on program schedule, cost, and functionality; assesses efforts to identify and address issues discovered during integration and testing; and evaluates the likelihood of a gap in satellite coverage and actions to prevent or mitigate such a gap. This book also evaluates NOAA’s progress on the Joint Polar Satellite System (JPSS) satellite program with respect to cost, schedule, and mitigation of key risks; identifies the benefits and challenges of alternatives for polar satellite gap mitigation; and assesses NOAA’s efforts to establish and implement a comprehensive contingency plan for potential gaps in polar satellite data.