TRUTHS on the table at ESA’s Ministerial Council

The ESA Council at Ministerial level, CM22, taking place in Paris, France, on 22–23 November 2022, will be a time for critical decisions. ESA’s Member States, Associate States and Cooperating States must together strengthen Europe’s space sector and ensure it continues to serve European citizens.

As the world faces the harsh reality of the climate crisis and agreements strive to implement mitigating policy, satellites are indispensable as they deliver key data to understand and monitor how the climate crisis is impacting our world.

For years now ESA has clearly demonstrated its leadership in realising pioneering satellite missions that return excellent science to understand and monitor our changing planet.

With TRUTHS, ESA is taking yet another step forward in its responsibility to act on climate change – and that is to ensure that decision-makers can be absolutely confident in the data they use for mitigation strategies and policymaking.

TRUTHS stands for Traceable Radiometry Underpinning Terrestrial- and Helio-Studies mission and ESA is developing the mission under the umbrella of its Earth Watch programme and on behalf of the UK Space Agency.

The satellite will host two main instruments: the Cryogenic Solar Absolute Radiometer and the Hyperspectral Imaging Spectrometer as well as the novel onboard calibration system.

Together, these instruments will make continuous measurements of both incoming solar radiation and solar radiation reflected from Earth up to 10 times more accurately than current satellites. These two observations will be used to evaluate the ratio between incoming and outgoing energy, and will also improve the quality of the global satellites observation system.

Essentially, the amount of incoming solar energy compared to the amount that bounces back to space controls our climate. An accurate knowledge of these energy exchanges is fundamental to understanding and monitoring change.

Nigel Fox, from the UK National Physical Laboratory, said, “TRUTHS will establish a metrology laboratory in space becoming a founding element of a future space-based climate and calibration observatory. Its high-accuracy measurements will enable benchmarks from which change can be detected in as short a time as possible facilitating timely climate action.

“Its novel calibration services will facilitate improved interoperability, not only between ESA and other space agency missions but also the new commercial space actors, maximising utility of all space assets and data.”

Philippe Goryl, upcoming chairman of the Working Group for Calibration and Validation within the International Committee on Earth Observation Satellites (CEOS-WGCV), added, “TRUTHS will increase confidence in satellite data through in-flight cross-calibration. Importantly, it will provide the means to transform the global Earth observation system by delivering traceable scientific and climate quality observations, enabling interoperability and harmonisation, starting with ESA missions and the Copernicus satellite fleet”.

“TRUTHS will be an important element of a future architecture of the Global Earth Observation System of Systems, facilitating the CEOS-WGCV to ensure long-term confidence in the accuracy and quality of Earth observation data and products.”

As with all new missions, the development process involves careful assessment and reviews – and the latest step for TRUTHS being that ESA Member State delegates approved it for subscription at the upcoming Council Meeting at Ministerial Level.

ESA’s Andrea Marini said, “Embraced by ESA Member States, TRUTHS has shown its attractiveness and demonstrated potential for becoming a new ESA mission for climate monitoring and calibration. This follows a successful definition study phase and the completion of the technical, scientific and programmatic reviews.”

Beth Greenaway, from the UK Space Agency, noted, “This landmark ESA mission, which will underpin the data collected from satellites and provide a benchmark reference for radiation measurements to improve our understanding of climate change, will now be on the table for investment at the upcoming ESA’s Council Meeting at Ministerial Level in November.

“TRUTHS demonstrates our strengths in Earth observation technology and highlights the importance of working with international partners, including Switzerland, Greece, Romania and the Czech Republic, to provide data that can be used by all for climate action.”

ESA’s upcoming Council Meeting at Ministerial Level is critical in the funding process so that TRUTHS can move further forward and become a reality.