ESA’s Biomass satellite enters scientific operation: forest and carbon data now open to all
The European Space Agency (ESA) has announced that the Biomass satellite has completed its commissioning phase and officially transitioned into scientific operations, making the mission's first operational products open and freely available to users. ESA describes this transition as the moment when the mission, after months of checks and calibrations, moves from promise to delivery: from proving that systems work correctly to the regular collection of data on forests, biomass, and associated carbon stocks.
Biomass was launched on April 29, 2025, on a Vega-C rocket from the space center in Kourou, French Guiana. It is an ESA mission from the Earth Explorer series, designed to develop new technologies and scientific methods for Earth observation. The focus of Biomass is a question that is increasingly important in climate policies, yet often difficult to measure in practice: how much carbon is stored in forests, where these stocks are located, and how they change under the influence of deforestation, degradation, fires, restoration, and climate change.
P-band radar: the first satellite to systematically “peek” beneath the canopy
The central asset of Biomass is an instrument that has not been operationally used in space in this way until now: P-band Synthetic Aperture Radar (SAR). Unlike shorter wavelengths, the P-band penetrates better through dense forest canopies, especially in tropical areas where vegetation is layered and optical observations are often hindered by cloud cover. This penetration capability is key to what ESA wants to achieve: measuring woody biomass, i.e., the mass of the trunk and larger branches, where the majority of forest carbon is located.
ESA explains that woody biomass is a reliable proxy for estimating stored carbon, as carbon is predominantly sequestered in the long-lasting woody part of the tree, rather than just in leaves and thin branches that change more rapidly. In practice, the satellite should provide globally comparable maps that can serve both scientists and public institutions: from researching the carbon cycle to monitoring the effects of forest policies and protection programs.
An additional advantage of the radar approach is its operability in conditions that are problematic for optical sensors. Radar works at night, is less sensitive to cloud cover, and in equatorial regions, constant cloud cover is one of the biggest obstacles to long-term vegetation monitoring. In this sense, Biomass targets the part of the planet where there is both the most biomass and the most uncertainty.
Completion of commissioning: calibration, fine-tuning, and the “green light” for science
After launch, Biomass did not immediately enter full operational use. Months were spent on commissioning, a phase in which instruments and systems are thoroughly checked, calibrated, and fine-tuned. Such a procedure is particularly important for radar missions in longer wavelengths, where data quality can be affected by interference in the radio frequency spectrum and ionospheric effects that distort the signal and require corrections.
The Biomass mission manager at ESA, Klaus Scipal, emphasized that the completion of commissioning reflects the joint effort of teams at ESA, industry, and the scientific community, and that the satellite, after months of work and cooperation, has confirmed it works as intended. In his interpretation, the transition to scientific operations means the mission is now assessed by what it delivers to users: the quality and consistency of data, rather than just a successful launch and technical functioning.
The opening of the “first stream” of data in late December 2025 allows users to become familiar with the format and characteristics of the products early on and to begin developing tools and methodologies. ESA emphasizes that these are initial levels of processing, which are the foundation for more advanced products in later phases of the mission, including tomographic and interferometric datasets.
How the planet will be imaged: tomographic global coverage then interferometric cycles
Biomass is not intended as a “one-off” forest scan. The operations plan, as described by ESA, begins with a global tomographic phase lasting about 18 months. Tomography allows for estimations of forest structure in the vertical dimension, which is especially important for areas where canopy height, density, and layering vary strongly over relatively small distances. In other words, the goal of the first phase is not only to map where forests are, but also to distinguish their internal architecture to better estimate biomass.
The tomographic phase will be followed by multiple interferometric global cycles, each lasting about nine months, through which changes can be monitored over time. Interferometry, simplified, compares different observations of the same area, thereby enabling the tracking of changes in vegetation structure and height, and indirectly, biomass. Such a time series is important for understanding both rapid events, like large fires or intensive logging, and slower processes, like recovery after degradation or long-term growth trends.
ESA points out that Biomass should reduce uncertainties in estimates of forest carbon stocks and flows, including those associated with forest loss and regrowth. Precisely this “dynamic component” – change over time, rather than just status at a single moment – is key for policy and management, as it allows for the verification of the effects of measures on the ground.
First views from Central Africa: a transect across Gabon and the Republic of the Congo
Among the first examples presented by ESA are estimates of forest carbon expressed in tons per hectare on a transect covering parts of Gabon and the Republic of the Congo, extending toward Cameroon and the Central African Republic. Such displays, first as a spatial map and then as a graphical cross-section, serve as a demonstration of capabilities: they show how estimates differ across various forest types, terrain, and landscape, and hint at what resolution and comparability could become available as processing further develops.
Maciej Soja, a senior researcher at Wageningen Environmental Research in the Netherlands, who has participated in the development of Biomass for over 15 years, stated that the first results are very encouraging, but the full potential of the mission is yet to come. He specifically highlighted that the upcoming tomographic and interferometric modalities will provide deeper insights into forest changes, which is important for both climate science and practical forest management, especially in Global South countries where forests are ecologically and economically crucial.
At the same time, ESA emphasizes an important caution: initial products are not the “final word” on the amount of carbon on the ground, but rather a first step in a system of products being developed and verified. For this reason, validation, calibration, and comparison with reference measurements are set as an equally important pillar of the mission as the imaging itself.
Calibration and ground verification: airborne campaign over Gabon
For satellite measurements to be reliable, it is necessary to link what the instrument measures with the actual situation on the ground. In such missions, this is done through a combination of field measurements, airborne campaigns, and comparisons with other reference data. ESA, therefore, as part of post-launch activities, organized an airborne campaign over Gabonese tropical forests involving scientists and experts from multiple institutions, including the German Aerospace Center (DLR), the Gabonese Agency for Space Studies and Observations (AGEOS), and the Gabonese Air Force.
The campaign involved flights of an aircraft equipped with a radar system designed for airborne operations. The flights, according to ESA descriptions, were carefully planned to coincide as closely as possible in time with the overpasses of the Biomass satellite, to obtain nearly simultaneous observations of the same area from two perspectives. Such a comparison allows for a more precise assessment of calibration and supports product validation before their wider scientific and practical application.
Tania Casal, an ESA scientist in charge of the campaign, pointed out that combining airborne and satellite radar observations over the extremely diverse Gabonese forests brings key insights into the calibration and performance of the mission. According to her, the results should strengthen confidence in Biomass tomographic measurements and demonstrate how countries investing in forest conservation can use consistent high-quality observations for better monitoring and planning.
Airborne data, according to ESA, are compared with satellite measurements to assess the accuracy and stability of the system. Such a procedure does not end with one campaign: validation is a process that continues in parallel with data collection, especially as more complex imaging modalities and higher-level products are introduced.
Role in climate policies: reducing uncertainty in forest carbon estimates
Climate goals and plans increasingly rely on understanding what is happening in the land and forestry sector. Forests can sequester large amounts of carbon and mitigate part of the emissions, but they can also become a source of emissions when degraded or cleared. In many regions, especially in the tropics, field measurements are expensive, fragmented, and temporally rare, so global estimates of carbon stocks are often burdened with wide ranges of uncertainty. This then trickles down into climate change models and discussions on how to value losses and gains in forests.
ESA Director of Earth Observation Programmes, Simonetta Cheli, stated that the lack of accurate global data on how much carbon forests store and how these stocks change has been one of the biggest challenges for scientists and decision-makers. In this framework, Biomass is presented as a mission that should significantly reduce uncertainties in estimates of forest carbon stocks and flows, including those associated with forest loss and regrowth. In practice, this could help in more precisely monitoring the consequences of deforestation and degradation, but also in assessing how effectively forests re-sequester carbon after restoration.
It is important, however, that such data are not interpreted out of context. Satellite measurements, no matter how advanced, must be combined with field inventories, local knowledge, and models that link biomass to carbon and respect differences among species and ecosystems. Biomass is conceived as a powerful global layer that reduces blind spots, but not as a replacement for field measurement where stand-level details are required.
For Global South countries, where tropical forests are crucial for both biodiversity and the economy, the availability of high-quality and open data can be important in a practical sense. In discussions on conservation and sustainable management, more reliable satellite data facilitate independent verification of trends, comparison of regions, and identification of areas where changes are most pronounced, regardless of whether changes occur due to logging, fire, or climate stress.
What is open and what follows: product levels and application development
ESA describes in the Biomass data documentation that products are created at multiple processing levels. At Level-1a/b, raw radar signals are processed into focused images with a series of corrections, including antenna characteristic compensations, interference suppression, and initial ionospheric effect corrections. Subsequent processing steps prepare interferometric and tomographic image stacks, from which forest structure parameters and biomass estimates are then derived.
Opening initial operational products allows users to develop quality check procedures, uncertainty assessments, and automated processing early on, and to set up analytical chains that will more easily accept more complex data modalities as the mission progresses. For public institutions and professional services dealing with forestry and environmental protection, this is an opportunity to become familiar with a type of data that could become a standard reference layer for large areas in the coming years, with the possibility of comparison with national inventories and other satellite sources.
ESA emphasizes that the mission plan is designed to deliver both a “structure image” in the first years and dynamic changes in later cycles. This is key for users who want to understand not only how much biomass exists, but also how forest systems are changing. Transparency is also important here: data openness encourages faster verification, comparison of methodologies, and the development of common standards.
Ljubljana at the center of the discussion: PolInSAR – Biomass 2026 from January 26 to 30
Simultaneously with the data opening, ESA is intensifying work with the research community. From January 26 to 30, 2026, an international gathering is being held in Ljubljana that combines the 12th Workshop on SAR Polarimetry and Polarimetric Interferometry (PolInSAR) and the 6th Biomass Science Workshop, along with the first meeting dedicated to the calibration and validation of Biomass. The gathering is designed as a place where scientists, students, and data users congregate, including communities working on carbon and climate modeling and topics related to international forest monitoring.
Klaus Scipal states that ESA is discussing advanced SAR methods for forest science and applications at the workshop and presenting Biomass capabilities, which is particularly important in the phase when the first operational data become available. In the first years of any new mission, such exchange of experiences often determines the direction of tools, standards, and best practices development, from technical processing issues to ways of interpreting results in the context of forest management.
For the European and global scientific community, such events also have practical value: they help align priorities, avoid duplication of work, and direct resources to problems that are most important for users. In the field of forest carbon, this often means questions of uncertainty, validation, and ways to smartly combine satellite estimates with field inventories and local data.
Why tropical forests are in focus and how mission success will be measured
Although Biomass will have global coverage, the mission is particularly important for tropical forests. Huge stocks of biomass are concentrated in these areas, but they also have the greatest uncertainties in estimates, as field measurements are difficult and optical satellites are often limited by cloud cover. P-band radar, with better penetration through the canopy, offers the possibility to monitor forest changes in a consistent way in regions that have been among the hardest for satellite biomass mapping until now.
Public announcements before launch emphasized that Biomass, through a multi-year series of measurements, would enable more detailed maps of biomass and changes, which can help in monitoring deforestation related to land-use change, but also in understanding restoration processes. ESA points out that the value of the mission increases over time: a longer data series allows for a clearer distinction between short-term oscillations and long-term trends, which is the foundation for both scientific analysis and higher-quality public policies.
Biomass is now in a phase where success will be measured through the quality and usability of products, but also through whether the data will indeed reduce uncertainties in the global carbon balance and whether it will become an operational tool in the hands of researchers, institutions, and countries that rely on forests as key natural infrastructure. By opening the first data and transitioning into scientific operations, ESA has sent a message that the mission is entering its most important stage: the one where space technology is transformed into information that can influence both the understanding of climate processes and forest management decisions on the ground.
Sources:- ESA Earth Online – announcement on the availability of the first open products from the Biomass mission ( link )
- ESA Earth Online – official page on data access and processing levels for Biomass ( link )
- ESA – official mission overview for Biomass and forest observation goals ( link )
- ESA – events calendar: ESA PolInSAR – Biomass 2026 (Ljubljana, January 26–30, 2026) ( link )
- CEOS – Biomass mission summary (launch date and basic instrument parameters) ( link )
- The Guardian – launch context, description of P-band radar, and tropical forest mapping goals ( link )
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