November 3, 2020 – Airbus has been awarded the lead in the European Space Agency (ESA) contract for the TRUTHS A/B1 (System feasibility Studies and Pre-Developments) as part of ESA’s Earth Observation Earth Watch programme. The TRUTHS satellite mission will collect measurements of the Sun radiation and of the sunlight reflected off Earth’s surface traced to an absolute metrological reference, which will then be used to improve the climatological data sets and calibrate the observations of other satellites. This space-based climate and calibration observing system will enable data from other satellites to be compared more easily providing greater standards of data harmonisation for even more accurate climate change forecasts. TRUTHS stands for Traceable Radiometry Underpinning Terrestrial and Helio Studies. The study will define the TRUTHS mission system implementation concept as well as focus on the preparation of critical technologies ahead of implementation of the mission in 2023. TRUTHS will carry a Cryogenic Solar Absolute Radiometer (CSAR) to provide a primary calibration standard in order to benchmark measurements of both incoming solar radiation and outgoing reflected radiation – measured with a Hyperspectral Imaging Sensor (HIS) also part of the payload – with unprecedented accuracy. These measurements will give the ability to estimate radiative imbalance underlying climate change and, importantly, in a shorter time than is currently possible. TRUTHS will serve to calibrate other satellite sensors, such as those carried on the Copernicus missions, through co-imaging operations.