Minimize What is FLEX?
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The Earth Explorer - Fluorescence Explorer (FLEX) mission will map vegetation fluorescence to quantify photosynthetic activity.

The conversion of atmospheric carbon dioxide and sunlight into energy-rich carbohydrates through photosynthesis is one of the most fundamental processes on Earth – and one on which we all depend.

Information from FLEX will improve our understanding of the way carbon moves between plants and the atmosphere and how photosynthesis affects the carbon and water cycles.

In addition, information from FLEX will lead to better insight into plant health and stress. This is of particular relevance since the growing global population is placing increasing demands on the production of food and animal feed.

At the moment, photosynthetic activity cannot be measured from space, but FLEX's novel sensor will observe this faint glow.

The FLEX satellite will orbit in tandem with one of the Copernicus Sentinel-3 satellites, taking advantage of its optical and thermal sensors to provide an integrated package of measurements.

Minimize Mission News
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Thales Alenia Space leads the build of photosynthesis mission

18 January 2019

A new contract seals the deal for Thales Alenia Space to lead the consortium that is building ESA's photosynthesis mission: FLEX.

LPVE2018 - Workshop on Land Product Validation and Evolution

10 November 2017

Following the successful LPVE 2014, the European Space Agency (ESA) is inviting scientists and Cal/Val experts to present the latest results from their on-going research at the 2018 Workshop on Land Product Validation and Evolution (LPVE 2018).

The abstract submission deadline has been extended to 30 November 2017.

Minimize Mission Details
  • Planned Launch Date: 2022

Mission objectives:

  • To assess the quality of fluorescence-derived photosynthesis data against classical optically-based methods (i.e. from fraction of absorbed photosynthetically active radiation times Light Use Efficiency).
  • To address in more detail temporal and spatial scaling issues (from towers to satellite footprints).
  • To identify and characterize the effects of different types of stress on fluorescence and photosynthesis (especially drought and freezing air temperatures).
  • To indicate potential applications of the novel fluorescence observations.

Mission orbit:

  • Orbit: Sun-synchronous
  • Measurement altitude: 815 km

Proposed configuration

The FLEX satellite configuration designs are based on careful consideration of:

  • Accommodation of the FLORIS payload so the instrument has an unobstructed view of the Earth
  • Pointing and coregistration requirements, which favour the isostatic mounting of the instrument on a specific payload support panel
  • Line of sight stability
  • Vega launcher fairing envelope, limiting the size and shape of the instrument and overall satellite


  • FLORIS is a high-resolution imaging spectrometer acquiring data in the 500-880 nm spectral range.

Launch vehicle:

  • Vega, from French Guiana

Ground Stations:

  • ESOC (Germany)
  • Kiruna (Sweden)
  • Troll (Antarctica)

Data processing:

  • Latency of 24 hours for Level-1 products to be expected.