TRUTHS shines
Satellites are essential for delivering key data to understand and monitor how the climate crisis is impacting our world, but, in turn, decision-makers need to be confident in the data they use for mitigation strategies and policymaking. TRUTHS, a new ESA mission, will do just this – and, now having passed an important milestone, it is one step closer to becoming a reality.
ESA is developing the Traceable Radiometry Underpinning Terrestrial- and Helio-Studies mission, or TRUTHS for short under the umbrella of its Earth Watch programme and on behalf of the UK Space Agency.
Slated for launch in early 2030, it will provide measurements of incoming solar radiation and of radiation reflected from Earth back out into space. Uniquely, TRUTHS will carry a primary International System of Units (SI) reference system. This means that TRUTHS’ measurements will be used as a benchmark to intercalibrate and improve data from other optical satellite instruments.
Presented this week at the Farnborough International Airshow in the UK, TRUTHS will be a ‘standards laboratory in space’, setting the ‘gold standard’ for climate measurements.
The TRUTHS 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 and Earth reflected solar radiation. These two observations will be used to evaluate the Earth’s energy-in to energy-out ratio.
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.
Now, this new mission has passed two important milestones in its development – the all-important technical and scientific reviews.
ESA’s TRUTHS Project Manager, Andrea Marini, explained, “We are proud to say that the mission has completed its definition and preliminary design phase.
“In essence, this means that ESA and Airbus, who head the contract for this development phase, have succeeded in shaping the mission and completing the initial design of the satellite and its very complex set of instruments. This was all completed in record time, in just 18 months.
“The mission concept meets all of the technical and scientific requirements that were set at its conception, and this has been recognised by independent technical and scientific authorities.”
Hazel Wood, TRUTHS Project Manager at Airbus, said, “Reaching this point of the programme is a major milestone for Airbus. The Airbus TRUTHS project team has led a UK and European consortium of industry experts which is necessary to deliver such a complex mission that will enhance our understanding of Earth's climate for years to come.”
When asked about the scientific impact of TRUTHS, Prof. Helen Brindley from Imperial College London and member of the TRUTHS Independent Science Review Board, said, “TRUTHS is a highly innovative mission that promises to be extremely useful to the climate science community with its unprecedented radiometric accuracy and uncertainty traceability.
“The unique measurements have the potential to improve measurement uncertainties for a wide range of satellite sensors, improving long-term records for a number of essential climate variables.”
With the satellite and instrument design consolidated and the scientific community assured it will deliver the data they need, the TRUTHS candidate mission is poised to be implemented as one of the new ESA Earth Observation Programmes to be funded at ESA’s Ministerial Council in November this year.
