The development of ESA’s Earth Explorer FLEX mission has recently passed a significant milestone: the mission’s all-important, single instrument has been joined to its satellite platform.

This delicate operation was carried out by spacecraft engineers at Thales Alenia Space in Cannes, France, following the delivery of the instrument from Leonardo in Florence, Italy.

FLEX’s fluorescence imaging spectrometer is called FLORIS for short and designed to map vegetation fluorescence around the globe and quantify photosynthetic activity and plant stress.

Photosynthesis is one of the most fundamental processes on Earth – essential for sustaining life. Most people know it as the mechanism that allows plants to grow by consuming carbon dioxide and releasing oxygen. However, few may realise that as plants photosynthesise, they also emit a very faint fluorescence signal.

Importantly, the signal, which is invisible to the naked eye, varies according to environmental conditions and the health of the plant – and can be used to assess plant health and stress.

With its FLORIS instrument, the FLEX mission will detect and measure this faint glow from space to offer better insight into plant health.

As prime contractor, Thales Alenia Space led the satellite platform assembly, integration and test campaign, which took place in Thales’ cleanroom in Belfast, Northern Ireland. Now that the platform and the FLORIS instrument have been integrated in Cannes, the next step is to carry out a final series of tests ahead of the launch scheduled in 2026.