CNES is preparing to deploy MicroCarb, Europe’s first space mission dedicated to measuring atmospheric carbon dioxide, to map global CO2 fluxes with a miniaturized infrared spectrometer. Set for launch on the night of 25–26 July from the Guiana Space Centre aboard a Vega-C rocket, the 180-kilogram microsatellite will operate in a 650-kilometre orbit, providing global coverage approximately every 25 days.
Mission and instrument
MicroCarb will use reflected sunlight over land and ocean to retrieve the proportion of CO2 in the atmospheric column at a native pixel size of roughly 4 x 9 square kilometres. The mission targets measurement accuracy better than 1 ppm, enabling detection of subtle gradients associated with sources, sinks and transport. An additional spectral band spanning oxygen absorption lines will be flown to improve corrections for scattering effects such as aerosols, aiming to enhance precision and data quality.
The spacecraft is built on CNES’s Myriade bus, demonstrating significant miniaturization compared with earlier missions of similar capability. The satellite’s compact design is intended to lower cost and logistics while maintaining high radiometric and spectral performance.
Key specifications
- Mass: ~180 kg (Myriade platform)
- Orbit: ~650 km
- Global revisit: ~25 days
- Ground sampling: ~4 x 9 km
- Target accuracy: better than 1 ppm
- Payload: miniaturized IR spectrometer plus an oxygen absorption band
- Launcher: Vega-C
Why it matters for carbon science
MicroCarb is designed to quantify global carbon sources and sinks and the exchanges between them, including seasonal dynamics. The mission will augment sparse ground networks with globally consistent measurements, supporting model validation and anomaly detection associated with events such as drought, deforestation or reforestation. After an initial evaluation phase comparing data with ground and balloon observations, operational exploitation over a planned five-year science mission will focus on refining flux estimates and improving understanding of feedbacks between climate and the carbon cycle.
Heritage, continuity and roadmap
MicroCarb builds on the heritage of greenhouse gas missions launched since the 2000s, including Japan’s GOSAT series and NASA’s OCO program. It is intended to help ensure continuity as OCO-2 nears the end of its operational life. The mission was developed by CNES with support from France’s PIA future investment program and contributions from the European Union and the UK Space Agency.
MicroCarb also acts as a precursor to ESA’s CO2M/Sentinel-7 constellation, planned within Europe’s Copernicus program. Whereas MicroCarb focuses on global fluxes, CO2M will target attribution of emissions, distinguishing natural from human-induced sources at higher spatial resolution (on the order of four square kilometres), enabling detailed assessments over cities and industrial regions.
Carbon cycle context
Natural carbon exchanges between sources and sinks amount to roughly 200 gigatonnes annually, driven by processes such as plant respiration, ocean-atmosphere exchange, and decomposition. Human activities add about 10 gigatonnes of carbon each year, disrupting this balance. Approximately half of anthropogenic emissions are absorbed by ecosystems and oceans, while the remainder accumulates in the atmosphere, contributing to the rise in CO2 concentrations from about 320 ppm in the mid-20th century to roughly 420 ppm today. High-precision, space-based observations like those from MicroCarb are central to tracking these trends and informing mitigation strategies.
For further details, see the CNES announcement: Satellites helping to understand the carbon machine.
