ESA’s Earth Explorer FLEX mission is designed to yield information about the health of the world’s plants by measuring a faint florescence glow they give off as they photosynthesise. Importantly, the signal, which is invisible to the naked eye, varies according to environmental conditions and the health of the plant – and, therefore, when measured, can be used to assess plant health and stress.

The information gathered by FLEX can be used to improve our understanding of how carbon moves between plants and the atmosphere and how photosynthesis affects the carbon and water cycles. The mission also offers better insight into plant health, which is especially important since Earth’s growing population is placing increasing demands on the production of food and animal feed.