The National Geodetic Survey (NGS) within NOS has a federal mandate to provide accurate positioning, including heights, to all federal non-military mapping activities in the USA. The NOAA NGS leads the GRAV-D Project (Gravity for the Redefinition of the American Vertical Datum) with a specific goal to model and monitor Earth’s geoid (a surface of the gravity field, very closely related to global mean sea level) to serve as a zero reference surface for all heights in the nation. Accurate heights are critical information needed for better understanding of threats to low-lying communities and coastal ecosystems from inundation by storms, flooding, and/or sea level rise. The GRAV-D Project has successfully utilized airborne gravimetry observations to collect highly precise gravity measurements throughout CONUS, Alaska, and their littoral regions. However, more than 85% of the targeted surface area still needs to be economically surveyed, including portions of Alaska, the Aleutian Islands, Hawaii, the US Pacific Island holdings, and most of interior CONUS.