Spire Global has developed, tested and deployed a constellation of nanosatellites with high-quality global navigation satellite system (GNSS) receivers. Data from the satellites will provide high-quality measurements (vertical profiles) of atmospheric temperature, pressure and water vapor via GNSS-occultation. The new constellation involves eight satellites capable of producing a minimum of 1,000 profiles a day. Spires launch schedule aims to increase this to at least 100,000 profiles a day within two years, providing a daily vertical sounding of the atmosphere in each 100 x 100km square across the planet. The methodology uses publicly funded and publicly available research and development on GNSS radio occultation (GNSS-RO) carried out by various research groups, including that responsible for the ongoing Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) constellation. Spires data access models conform to the World Meteorological Organizations (WMO) Resolution 40, which governs the provision of meteorological data. For example, the companys purchase once, distribute everywhere license allows for unlimited worldwide redistribution, meaning that data is free at the point of use for public weather predictions. The satellites are manufactured in Glasgow, Scotland, UK, and can be built and launched within weeks due to their small size.