FLEX

ESA’s Fluorescence Explorer (FLEX) launched with Copernicus Sentinel-3C on Vega-C flight VV30 on September 15, 2026. Its FLORIS imaging spectrometer detects the faint solar-induced fluorescence emitted by vegetation, supporting estimates of photosynthetic activity, plant stress and ecosystem productivity. Two pushbroom spectrometers sharing telescope optics capture complementary spectral resolutions. The mission is designed to combine fluorescence with near-simultaneous Sentinel-3 atmospheric and land-surface observations, improving interpretation of the weak signal embedded in reflected sunlight. ESA’s launch account specifies an initial tandem with Sentinel-3A, followed later by Sentinel-3C; the launch begins commissioning rather than establishing an already validated long-term data record.