The European Space Agency’s FLEX Earth Explorer satellite and the Copernicus Sentinel-3C satellite have been launched together aboard a Vega-C rocket from Europe’s Spaceport in French Guiana, marking a new milestone in Europe’s Earth Observation Programmes.

Two Earth observation satellites – ESA’s Fluorescence Explorer (FLEX) satellite, and the third satellite for the Copernicus Sentinel-3 mission – are encapsulated inside the nose cone of a Vega-C launcher and are awaiting liftoff at Europe’s Spaceport in French Guiana.

On 15 September, two spacecraft will leave Earth together aboard the same launcher from Europe’s spaceport in Kourou: FLEX, ESA’s photosynthesis mission, and Sentinel-3C, Copernicus’ newest satellite monitoring Earth’s oceans, land, ice and atmosphere.At ESA’s European Space Operations Centre (ESOC), two independent mission teams are preparing to operate the spacecraft in parallel in a closely coordinated effort. As launch approaches, they are rehearsing side by side to prepare not only for their own missions, but also for the moments when the two operations intersect.

If you had to describe a plant, the first thing you might start with is its colour – and the first colour that usually comes to mind, is green. And indeed, by and large, plants appear green to our eyes because they contain chlorophyll, which absorbs blue and red light much more strongly than green light. Behind this green façade though, plants are secretly glowing. This phenomenon is called solar induced fluorescence, and it gives scientists an unusual way to spy on photosynthesis – all the way from space.As ESA prepares to launch its Fluorescence Explorer (FLEX) mission on 15 September 2026, here are 10 surprising facts about this faint glow that could transform how we assess the health of Earth's vegetation.

Sentinel-3C ontop of the Vespa adapter which encases FLEX

FLEX and Sentinel-3C atop Vega-C

Alexandra Lora, Spacecraft Operations Engineer for ESA’s FLEX mission

Isabelle Dauvin, a Spacecraft Operations Manager for ESA’s FLEX mission