Europe's new atmospheric chemistry missions in space: The Path to Operations of Copernicus Sentinel-4/UVN and Sentinel-5/UVNS.

The Copernicus Sentinel-4/UVN and Sentinel-5/UVNS imaging spectrometers, hosted on EUMETSAT’s Meteosat Third Generation - Sounder (MTG-S) and EUMETSAT Polar System - Second Generation A (EPS-SG A) satellites, are in space since the summer of 2025. Sentinel-4/UVN is designed to monitor atmospheric trace gases - such as ozone, nitrogen dioxide, sulphur dioxide, formaldehyde and glyoxal - as well as aerosol and cloud properties from hyperspectral measurements in the UV, Visible and Near-Infrared (UVN). Observing from a geostationary orbit, it provides high spatial resolution and hourly coverage over Europe and northern Africa. Sentinel-5/UVNS has a similar scope but additionally covers spectral bands in the Shortwave-Infrared and therefore allows measuring additional species, such as carbon monoxide and methane. Flying in a polar orbit, it provides high spatial resolution and near-daily global coverage. Both instruments provide essential data for tracking atmospheric composition and support the Copernicus Atmosphere Monitoring Service (CAMS). The innovative instruments are completing the European contribution to the constellation of geostationary and polar orbiting atmospheric composition missions, including the existing geostationary GEMS and TEMPO over Asia and North America, respectively, as well as the fleet of Low Earth Orbit air quality missions operating in similar spectral ranges, such as GOME-2, OMI, TROPOMI and OMPS. This presentation will cover the mission status during the ongoing commissioning and Cal/Val activities, including insights into level-2 product status.