Mission typeEarth observing satellite
Mission duration3.5 years (planned)[1]
Spacecraft properties
ManufacturerThales Alenia Space
Launch mass460 kilograms (1,010 lb)
Start of mission
Launch dateMid 2025 (planned)[2]
Launch siteKourou ELV
Orbital parameters
Reference systemGeocentric
Altitude814 km
Repeat interval27 days

The FLuorescence EXplorer (FLEX) is a planned mission by the European Space Agency to launch a satellite to monitor the global steady-state chlorophyll fluorescence in terrestrial vegetation.[3] FLEX was selected for funding on 19 November 2015[3][4][5][6][7][8][9][10] and will be launched on a Vega C rocket from Guiana Space Centre in mid-2025.[2]


The FLuorescence EXplorer (FLEX) mission is the eighth mission in the Earth Explorer programme, (part of ESA's Living Planet Programme). It comprises a satellite for the global monitoring of steady-state chlorophyll fluorescence in terrestrial vegetation.[11] Leaf photosynthesis releases energy not required in the biochemical process in the form of light in wavelength between 640 and 800 nanometres.[3]

After more than 70 years of basic and applied research in chlorophyll fluorescence, it is now established that fluorescence is a sensitive indicator of photosynthesis in both healthy and physiologically perturbed vegetation that can be used to monitor croplands and forests.[3]

Fluorescence is a powerful non-invasive tool to track the status, resilience, and recovery of photochemical processes, and provides important information on overall photosynthetic performance with implications for related carbon sequestration. The early responsiveness of fluorescence to atmospheric, soil and plant water balance, as well as to atmospheric chemistry and human intervention in land usage, makes it a useful biological indicator in improving the understanding of Earth system dynamics.

FLEX will encompass a three-instrument array for measurement of the interrelated features of fluorescence, hyperspectral reflectance, and canopy temperature.

The program will involve a space and ground-measurement program of 3-years duration and will provide data formats for research and applied science.

See also


  1. ^ "Fluorescence Explorer (FLEX) – Facts and Figures". ESA. Retrieved 3 January 2020.
  2. ^ a b "Arianespace to launch with Vega C FLEX & ALTIUS, two ESA programmes at the service of environment". Arianespace (Press release). 11 January 2022. Retrieved 11 January 2022.
  3. ^ a b c d Amos, Jonathan (19 November 2015). "Flex satellite will map Earth's plant glow". BBC News. Retrieved 2015-11-20.
  4. ^ de Selding, Peter B. (25 September 2015). "Panel Endorses Vegetation Fluorescence Mapper for ESA's Earth Explorer Program". Spacenews. Retrieved 3 October 2015.
  5. ^ Kraft, S; Del Bello, U; Bouvet, M; Drusch, M; Moreno, J (2012). "FLEX: ESA's Earth Explorer 8 candidate mission". 2012 IEEE International Geoscience and Remote Sensing Symposium. pp. 7125–7128. doi:10.1109/IGARSS.2012.6352020. ISBN 978-1-4673-1159-5. S2CID 7603157.
  6. ^ Kraft, S; Bézy, J.-L; Del Bello, U; Berlich, R; Drusch, M; Franco, R; Gabriele, A; Harnisch, B; Meynart, R; Silvestrin, P (2013). "FLORIS: Phase a status of the fluorescence imaging spectrometer of the Earth Explorer mission candidate FLEX". In Meynart, Roland; Neeck, Steven P.; Shimoda, Haruhisa (eds.). Sensors, Systems, and Next-Generation Satellites XVII. Vol. 8889. pp. 88890T. doi:10.1117/12.2032060. S2CID 128624334.
  7. ^ Drusch, Matthias; Moreno, Jose; Del Bello, Umberto; Franco, Raffaella; Goulas, Yves; Huth, Andreas; Kraft, Stefan; Middleton, Elizabeth M; Miglietta, Franco; Mohammed, Gina; Nedbal, Ladislav; Rascher, Uwe; Schuttemeyer, Dirk; Verhoef, Wout (2017). "The FLuorescence EXplorer Mission Concept—ESA's Earth Explorer 8". IEEE Transactions on Geoscience and Remote Sensing. 55 (3): 1273–1284. Bibcode:2017ITGRS..55.1273D. doi:10.1109/TGRS.2016.2621820. S2CID 5267592.
  8. ^ Stoll, M.P; Buschmann, C; Court, A; Laurila, T; Moreno, J; Moya, I (2003). "The FLEX-Fluorescence Explorer mission project: Motivations and present status of preparatory activities". IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477). Vol. 1. pp. 585–587. doi:10.1109/IGARSS.2003.1293850. ISBN 978-0-7803-7929-9. S2CID 56932583.
  9. ^ Rascher, Uwe; Gioli, Beniamino; Miglietta, Franco (2008). "FLEX — Fluorescence Explorer: A Remote Sensing Approach to Quantify Spatio-Temporal Variations of Photosynthetic Efficiency from Space". Photosynthesis. Energy from the Sun. pp. 1387–1390. doi:10.1007/978-1-4020-6709-9_299. ISBN 978-1-4020-6707-5.
  10. ^ Harnisch, Bernd; Kraft, Stefan; Bézy, Jean-Loup; Drusch, Matthias; Bouvet, Marc; Del Bello, Umberto (2017). "Fluorescence imaging spectrometer concepts for the Earth explorer mission candidate flex". International Conference on Space Optics — ICSO 2012. p. 72. doi:10.1117/12.2309086. ISBN 9781510616172. S2CID 125313615.
  11. ^ "FLEX (Fluorescence Explorer)". www.eoportal.org. Retrieved 2022-12-28.