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TRUTHS mission development

Delivering accurate Earth observation data

Slated for launch in early 2030, the TRUTHS mission will enable, for the first time, high-accuracy SI-traceability to be established in space. Incorporating technology initially conceived at NPL more than 20 years ago, the TRUTHS mission was accepted into the ESA Earthwatch programme in November 2019, and was funded to move forward to full flight implementation in November 2022. As UK-led European Space Agency mission, TRUTHS will be delivered by a multi-national consortium which will include resources not only from the UK but European partners from Greece, Spain, Romania and the Czech Republic also.

In July 2022, the TRUTHS mission achieved an important milestone in passing critical technical and scientific reviews. This marked the completion of its so-called Phase B1, the preliminary design phase, during which the satellite and instrument design were consolidated. With the mission concept recognised, by independent review, to meet all of the technical and scientific requirements set at its conception, the mission will now progress towards full flight implementation with a launch by early 2030.

Subset of TRUTHS team at ESA’s Living Planet Symposium 2022. Represented here: NPL, ESA, UKSA, Airbus UK, Telespazio, CGI, University of Leicester, University of Zurich


NPL’s involvement

NPL is not directly involved in building the space hardware for TRUTHS, however our expertise is integral to the mission development. The NPL team provide support to the design of the mission as part of the industrial consortium, particularly related to the on-board and pre-flight calibration and characterisation concepts.  The team is providing the algorithms to assess and characterise the uncertainty of the mission’s data products, and also how it will transfer its calibration to other missions. 

In addition, NPL provides the UK mission science and engineering lead, Professor Nigel Fox, who also leads a consortium of primarily academic organisations to perform the complementary science and independent engineering studies to specify the mission’s observational requirements and technical specifications. Through this project it provides support to ESA and the industrial consortium to enable agile trade-offs to be carried out between science need and engineering practicalities.

The Earth observation satellite data from TRUTHS will be directly downloaded to a single receiver station likely to be in Svalbard and from there transmitted to a data processing centre in the UK. As the TRUTHS data is considered a ‘public good’ it will be provided free and open to any user. In addition to improving our understanding of the planet and the effectiveness of strategies to mitigate against climate change, it is expected that TRUTHS will help facilitate further growth in commercial services for Earth observation and climate data benefiting the UK economy.

Professor Nigel Fox

The TRUTHS mission can be thought of as ‘putting NPL into space’ a ‘gold standard’ reference which will enable SI traceability to be established in space for Earth Observation data in the same way that we do for other terrestrial products and services such as time, mass and length, leading to increased trust in Earth observation, as well as climate data and services.

Professor Nigel Fox - NPL


Find out more

Mission objectives

SI traceability in-flight

Learn more about TRUTHS


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