The European Space Agency's FLEX satellite was fuelled at Europe's Spaceport in French Guiana on 20 August, ahead of its planned launch on 15 September at 03:21 CEST.

FLEX is an Earth Explorer mission that carries a Fluorescence Imaging Spectrometer to measure the faint fluorescence emitted by plants during photosynthesis. The instrument will produce global maps of vegetation fluorescence at a spatial resolution of 300 m x 300 m, enabling scientists to assess photosynthetic activity and plant health.

The satellite arrived in French Guiana in mid-July together with the Copernicus Sentinel-3C satellite after a two-week sea voyage from Nice, France. Engineers at the Spaceport completed inspections and preparations for integration with a Vega-C launch vehicle. The fuelling operation, which involved loading 30 kg of propellant, was carried out under strict safety procedures by a specialised team. Frank de Bruin, ESA's Launch Campaign Manager for FLEX, said, "Preparations to ready our satellite for launch have been going very well here at Europe's Spaceport and I thank everyone involved. For fuelling, everyone apart from the fuelling experts left the cleanroom for safety reasons. Everything went according to plan and FLEX is now fully loaded." The next steps will involve attaching FLEX to its launcher adapter and encapsulating it within the Vega-C fairing.

FLEX is scheduled to operate for a minimum of 3.5 years, observing at least three seasonal vegetation cycles in the northern and southern hemispheres. Data will be made available to researchers after commissioning.