: Part of the European Space Agency’s Earth Explorer series of satellites, the Flex (Fluorescence Explorer)
will use a novel sensor to detect the faint fluorescence emitted by plants as they convert sunlight into chemical energy during photosynthesis. Flex will orbit Earth in tandem with another satellite, which has optical and thermal sensors. From those data, researchers will be able to better monitor plant health and detect problems before plants begin to brown, wilt, or show other visible signs of stress. The researchers also plan to study the movement of carbon between plants and the atmosphere and how photosynthesis affects the carbon cycle. The information they gather on plant health could prove important for feeding Earth’s ever-increasing population.