European Space Agency (ESA)'s Atmospheric Limb Tracker for Investigation of the Upcoming Stratosphere (Altius) mission carries a high-resolution spectral imager that images in the ultraviolet, visible and near-infrared channels and uses a limb-sounding technique to deliver profiles of ozone and other trace gases in the upper atmosphere to support services such as weather forecasting, and to monitor long-term trends. Altius will not look straight down on Earth, but will observe the atmosphere along Earth’s horizon. The ‘limb-sounding’ technique allows trace gases such as ozone to be profiled so that concentrations can be seen at different altitudes with high vertical resolution. These data will be a valuable complement to that provided by nadir-looking missions such as Copernicus Sentinel-5P, Sentinel-4 and Sentinel-5.

Altius is developed within ESA’s Earth Watch programme and financed mainly by Belgium with contributions from Canada, Luxembourg and Romania.

European Space Agency (ESA)'s Fluorescence Explorer (FLEX) will yield information about the health of the world’s plants. FLEX will carry a florescence imaging spectrometer called Floris to map vegetation fluorescence around the globe and quantify photosynthetic activity and plant stress. It will detect and measure the light emitted by plants as they convert sunlight and the atmosphere’s carbon dioxide into energy. While this photosynthetic activity is invisible to the naked eye, the instrument will observe the fluorescence of vegetation, yielding important information about plant health. The information gathered will be used to improve our understanding of how carbon moves between plants and the atmosphere and how photosynthesis affects the carbon and water cycles.