Airbus, a component of the Earth Observation Earth Watch programme of the ESA (European Space Agency), has been awarded the latest stage of the Traceable Radiometry Underpinning Terrestrial and Helio Studies ( TRUTHS) mission. The contract specifies the mission and payload in great detail, focuses on payload development and risk mitigation, and provides for possible hardware acquisition with a lengthy lead time before the complete implementation phase after the 2025 ESA Ministerial budget meeting. Including options, the contract is valued at €109.3 million and was inked at COP28 in Dubai.
Compared to a precise reference, the measurements of solar radiation and sunlight reflection off the Earth’s surface by the TRUTHS satellite mission will be used to calibrate the observations of other satellites and enhance climatological data sets. Implementing this space-based climate and calibration observing system will facilitate the comparison of data from additional satellites, thereby elevating the benchmark for data harmonisation and enhancing the precision of climate change predictions.
The contract brings Airbus one step closer to building a mission enabling scientists and climatologists to cross-reference their measurements and data, allowing for significantly more precise forecasts and analyses in less time, according to Airbus Head of Space Systems Jean-Marc Nasr. He said TRUTHS will provide the gold calibration standard for space-based Earth observation, functioning as a “standards laboratory in space.”
Andrew Griffith, minister of science, research, and innovation of the United Kingdom, stated that this mission, led by the United Kingdom, will provide invaluable measurements to advance the understanding of climate change and have a global impact. Under the supervision of Airbus UK, this endeavour fosters expansion and cultivates significant industrial capacities within the space domain, propelling the United Kingdom’s aspirations to become a technological and scientific superpower.
This final phase will consist of defining the mission and payload’s design, recruiting industrial partners necessary to deliver the payload’s complexity, and establishing optical Earth instrumentation expertise in the United Kingdom. This enhanced capability in the United Kingdom will provide future Earth observation satellite missions in Europe with access to new skills.
TRUTHS will carry a cryogenic solar absolute radiometer (CSAR) as a primary calibration standard to provide unprecedented accuracy in measurements of both incoming solar radiation and outgoing reflected radiation – measured with a Hyperspectral Imaging Sensor (HIS) also included in the payload. These measurements will determine the radiative imbalance underlying climate change in less time than is now achievable. Through co-imaging operations, TRUTHS will calibrate other satellite sensors, such as those used on Copernicus missions.
TRUTHS is supported by a group of ESA member countries led by the United Kingdom, including the Czech Republic, Greece, Romania, Spain, and Switzerland. Surrey Satellite Technology Ltd, Teledyne e2v, National Physical Laboratory, Rutherford Appleton Laboratory, Deimos Space UK Ltd and AVS-UK Ltd, Thales Alenia Space Switzerland, Deimos Space SRL, Sener, and Integrated Systems Development are among the partners assisting Airbus with the initial development of the satellite. Other companies and institutes from the participating countries will also make significant contributions.
The United Kingdom has launched a strategy to seize the lead in this domain, capitalising on the substantial scientific knowledge of climate science of institutions such as the National Physical Laboratory, the National Centre for Earth Observation, and the Rutherford Appleton Laboratory Space.
