If a plant isn't green it doesn't mean it can't photosynthesise as well as its more usual counterpart, but when measured by satellites, these non-green varieties skew results on plant health. FLEX is different. Experiments using 'mutants' show that colour won't be an obstacle in this new mission's task of mapping plant health from space.

Planned to be launched around 2022, ESA's Fluorescence Explorer - FLEX - will use a novel technique to track the health of the world's vegetation.

This technique involves detecting and measuring the faint glow that plants give off as they use sunlight to convert carbon dioxide into energy-rich carbohydrates - photosynthesis.