Photo credit  |  ESA/NASA


Missions  |  26 February, 2020  |  Reading time: 2 minutes

TRUTHS: A UK Space Agency climate mission led by the National Physical Laboratory (NPL) to track climate change more accurately from space.

Mission facts

  • The first UK Space Agency-led climate mission in space
  • Has the capability to deliver up to a 10-fold increase in accuracy of climate data sensors to reduce uncertainty in Earth Observation (EO) data
  • Supporting faster & more confident decision-making about climate change
  • Providing an upgrade in calibration of satellites while they are in space
  • TRUTHS will send back more than 5 terabytes of trusted EO & climate data to Earth every day from a satellite the size of a large washing machine

What are the benefits?

  • Faster decisions about actions world leaders need to take in the face of climate change and monitoring the impact of their success
  • Based on more confident (reliable, trusted) information with reduced uncertainty in how the Earth’s temperature is changing and its consequences
  • Putting the UK space sector at the forefront of global policy decisions on climate change for the benefit of society and economy in the UK and the world
  • Inspiring the next generation and the wider public to get involved in the UK space sector and understanding the impact of climate change
  • Enabling a UK programme to exploit TRUTHS’ data and the interoperability from other complementary satellites, opening up new areas of work for data scientists, engineers and climate scientists and facilitating new commercial climate services.

Mission summary: How will TRUTHS work?

Many satellites collect data, measuring how our planet is changing, but as they orbit the Earth the calibration of their instruments gradually drifts, making the measurements they send back less accurate, despite on-board recalibration systems and the use of ground targets for re-calibration.

The TRUTHS satellite will be a calibration laboratory in space, increasing the accuracy of calibration of orbiting satellites – big and small – by up to 10 times, upgrading the performance of the whole Earth Observation (EO) system. It will benchmark global climate measurements with uncertainty levels that are small enough that future change can be detected in as short a time as possible.

This is key in providing governments and world-leaders with evidence based on trusted, reliable climate data, to enable better informed decision-making.

TRUTHS stands for Traceable Radiometry Underpinning Terrestrial- and Helio- Studies and the satellite will carry a hyperspectral imager to take detailed measurements of incoming radiation from the Sun as well as radiation reflected back from the Earth, improving our understanding of climate change and the changing temperature of the Earth. However, what makes TRUTHS unique is the revolutionary on-board calibration system. Devised by NPL this places on board the satellite an ultra-high accuracy reference standard which enables daily calibrations against an invariant constant reference.

Computer generated image of the TRUTHS satellite | NPL

UK expertise

TRUTHS is a breakthrough concept by NPL (the National Physical Laboratory, based in Teddington, Middx) to launch the first climate mission led by the UK Space Agency, implemented through the European Space Agency (ESA).

The climate mission reflects the UK’s ambition to continue to be a global leader in climate observations, services and policy guidance on climate activities for the world.

Find out more about the mission concept and how it is being built here:

TRUTHS was adopted into the ESA programme in 2019 and is 85% funded by the UK (through ESA). The remainder comes from Switzerland, Greece, the Czech Republic and Romania who will build elements of the mission reflecting their technical expertise and the priorities of their own countries but led by and managed from an industrial lead from the UK. NPL is the scientific leader of the mission and will provide the disruptive on-board calibration system.

The first 2½ year €32m phase began early in 2021 and is to produce a detailed design, prototyping and demonstration of key technologies. A UK-led consortium to undertake this first phase will be appointed in summer 2020 following a tender process. Following a successful first phase the satellite hardware will be built from 2023 with a scheduled 2026 launch date, most likely from ESA’s launch facility in French Guyana, South America.

CGI will develop the preliminary definition of the Payload Data Ground System that will be responsible for:

  • exploitation of the instrument data
  • facilities responsible for mission planning and control
  • quality control including calibration, validation and monitoring
  • instrument performance assessment vital to delivering reliable data to scientists and the precise orbit determination
  • user services interface and acquisition, processing and archiving.

Alongside TRUTHS, the UK aims to develop a related national programme to inspire the next generation of climate scientists, data scientists and software engineers in readiness to increase our capacity to exploit the data it sends back to Earth and to improve decision-making, sustainable growth and quality of life in UK society.

Team insight

Nigel Fox devised the concept and design of TRUTHS and is the Science Lead in Earth Observation at NPL:

“This climate mission puts the UK at the forefront of space-based Earth observation, it will become the ‘gold standard’ for EO data which will underpin global climate information services going into the future.

“TRUTHS will improve the performance of constellations of small, low cost satellites so they can become part of the scientific decision-making system. Bigger main-stream satellites will also benefit because they will be less dependent on costly on-board calibration systems.

“Many different global sectors will benefit from this mission – from governments’ policy decisions to the commercial sector, not only the space sector. For example, the UK Government will be able to take earlier strategic decisions on when to build the next Thames Barrier, for instance, and how big it should be to cope with changes in extreme events such as tidal surges and flooding, so the whole of society and our economy will benefit.

“TRUTHS will send more than 5 terabytes of trusted EO and climate data back to Earth every day from a satellite little bigger than a washing machine.”

“It is the first time we as a country have had such a significant role in defining and building a mission from the UK and it opens up whole new areas of work for our scientists, engineers and climate scientists. TRUTHS will send 5-10 terabytes of trusted EO and climate data back to Earth every day from a satellite little bigger than a washing machine.

“But it is not just about building the satellite and its payload but also about engaging the public and the next generation to get involved in space instruments and the data and application of the data that comes out of it. Our expectation is that we will run alongside TRUTHS a national programme to prepare to exploit the data from TRUTHS, and that of other satellites made interoperable by TRUTHS, so the UK becomes a global hub for trusted EO and climate data and services.”