FRM4FLUO: A Successful Step Toward FLEX Mission Validation

In June 2025, JB Hyperspectral Devices participated in a major milestone of the FRM4FLUO project, a highly successful field campaign in Tuscany, Italy, aimed at supporting the European Space Agency’s (ESA) upcoming  FLEX (Fluorescence EXplorer) mission. Other leading research and industry players involved were Milano-Bicocca University, Forschungszentrum Jülich, CNR and ITUBS.

The field experiments were carried out on a working farm in Tuscany, Italy, a site that has collaborated with the European Space Agency (ESA) for several years. With over 1,000 cows and bulls, the farm provided a real-world environment that allowed the team of scientists to perform controlled measurements. Data was collected from up to five locations across the farm, with the goal of validating solar-induced fluorescence (SIF) at multiple observational levels such as ground, leaf, helicopter and drone-level. 

This work was part of the FRM4FLUO project (Fiducial Reference Measurements for Fluorescence), an ESA-funded initiative, to validate measurements for the upcoming FLEX (Fluorescence Explorer) satellite mission launching in 2026.

JB Hyperspectral Devices played a key role in this campaign. On the ground, our FLoX system was deployed to continuously measure chlorophyll fluorescence and reflected radiance at the leaf and stand levels. The same core technology was also used at the airborne level through our  AirFloX, integrated into the Helipod, which was mounted on a helicopter. The Helipod equipped with over 60 sensors, is capable of collecting diverse optical and biophysical parameters simultaneously. AirFloX, a point spectrometer, measures reflected radiance by the plants and derives chlorophyll fluorescence emitted by the plants. Using the same spectral measurement principles in both FLoX and AirFloX ensures consistency and traceability across different observational levels.

ESA representatives were present on-site, monitoring and testing validation protocols that will later be applied to FLEX satellite operations. These validations are critical because the  FLEX satellite, orbiting hundreds of kilometres above the Earth, relies on ground-verified measurements to ensure its fluorescence data is reliable. Without detailed reference data collected across multiple platforms and spatial scales, it would be impossible to fully trust or interpret  FLEX’s global observations of photosynthetic activity.

We are excited for the launch of FLEX in 2026 and confident that the results of this field campaign will significantly contribute to the calibration, validation and scientific readiness of the mission!