Using cutting-edge technology, ESA’s FLEX mission is designed to reveal new insights into how plants function by measuring the faint fluorescence they emit as they capture light during photosynthesis. To do this the satellite carries an instrument called FLORIS.

The animation shows light from Earth entering FLORIS through the instrument aperture. The polarisation effects are removed, and the light is then focused by the telescope optic before being separated into two dedicated optical paths: one feeding the high-resolution spectrometer (optimised for the faint fluorescence signal) and the other feeding the low-resolution spectrometer (which records complementary atmospheric and reflectance data). Finally, the light is dispersed into its constituent frequencies and converted by highly sensitive detectors into digital data, enabling FLEX to reveal the activity and health of vegetation across our planet.