MicroCarb, a joint mission between the UK Space Agency and CNES, France, successfully launched on 26 July 2025. The groundbreaking mission will map atmospheric carbon dioxide (CO2) concentrations, the principal greenhouse gas driving global warming, with the aims to better understand sources and sinks of carbon.
Understanding the behaviour and interchange of greenhouse gases in the Earth’s atmosphere is crucial for comprehending our changing climate.
NPL has been key to enabling the accuracy of the CO2 measurements from MicroCarb, providing the SI-traceable optical ground calibration facility, used by Airbus France (the prime contractor) to test and verify the instrument performance before launch. NPL’s work, led by Paul Green, Principal Scientist will, in addition, develop algorithms and quality metrics on the CO2 product post-launch, working alongside the wider MicroCarb team to ensure accurate actionable data throughout its nominal 5-year mission lifetime.
As the first European mission designed to characterise greenhouse gas fluxes on Earth’s surface, MicroCarb measures will allow scientists to better understand how much carbon is absorbed by oceans and forests, the planet's main carbon sinks. The mission will enhance the work of previous CO2 missions (primarily from the US and Japan) and become a key element in the international greenhouse gas monitoring network of satellites. The highly accurate CO2 concentration data (1 part per million, or 0.25%) derived from MicroCarb will enable small geographical fluctuations to be identified, so attribute local sources and sinks. This will improve our understanding and monitoring of the natural carbon cycle and emissions from human activity.
MicroCarb will ultimately support the monitoring of progress towards national and international emission-related climate targets including the UK net zero targets and the UNFCCC Paris Agreement.
Once in orbit at an altitude of 650 km, MicroCarb will measure the same point on the ground at the same time of day, repeating its observation (of a particular location) every 21 days. It will carry an infrared spectrometer capable of measuring O2 and CO2 concentrations at four different spectral bands in sunlight reflected off the Earth. The high accuracy CO2 data will have a nominal pixel size of 4.5 x 9 km, with a targeted zoomed in ‘city-scanning’ observing mode at a higher 2 km x 2 km resolution, to better understand emissions from cities like London or Paris.
UK entities play a significant role in this mission, contributing to the assembly, integration, and testing of the satellite, as well as the design and build of key components. Mission partners include: NPL, UK Space Agency, National Centre for Earth Observation, University of Edinburgh, University of Leicester, RAL Space, GMV and Thales Alenia Space.
Paul Green, Principal Scientist, NPL said: “The launch of MicroCarb, as the first European sensor to map CO2 concentrations is a massive step forward for the UK and France to contribute to our understanding of the Earth’s response to continued greenhouse gas emissions. Its high accuracy data, contributing to a wider global GHG observing system, will show the efficacy of international policies towards new zero and help us make better decisions to reduce and combat the worst consequences of a changing climate.”
Dr Peter Thompson CBE, CEO at NPL, said: “Missions like MicroCarb provide the data needed to understand complex interactions like the global carbon cycle, the anthropogenic contribution to it and the efficacy of implemented policy. Working with UK and international partners on this mission is vital for providing science-led solutions for climate action and a sustainable future.”
Dr Paul Bate, Chief Executive of the UK Space Agency, said: “Satellites like MicroCarb are our eyes in the sky. Over half of the critical data we use to understand climate change comes from space, and MicroCarb’s successful launch is a major leap forward in our ability to track carbon emissions and absorption with unprecedented accuracy, from the world’s cities to its forests and oceans.
“Backed by UK and French investment and expertise, it’s a proud moment for both our space sectors and a powerful example of international collaboration in action.”
28 Jul 2025