The SCARBOn Constellation: How the Mission Architecture Comes Together

​Monitoring anthropogenic CO₂ concentrations from space with high temporal and spatial coverage requires more than a single satellite. It calls for a well‑designed satellite constellation – a coordinated system that can observe large areas, revisit them frequently and deliver consistent, high‑quality data. The SCARBOn architecture, designed by Airbus Defence and Space, brings these elements together into an integrated mission concept.​

A constellation built for daily global coverage

The SCARBOn constellation is constituted by several satellites working together to provide reliable greenhouse gas (GHG) observations using NanoCarb and SPEXone instruments. Thanks to the adjustment of the orbit selection, the number of satellites and the performance of the instrument suite, it supports global GHG monitoring on a daily basis. This frequent mapping is essential for monitoring anthropogenic emissions and understanding how they evolve over time.

​Each satellite observes a wide swath of Earth’s surface, allowing the constellation to cover large regions efficiently and revisit them frequently without requiring an unrealistic number of satellites. The swath width and spatial resolution have been carefully selected to balance observation capabilities with practical constraints, such as power consumption, data volume and overall spacecraft performance.​

Optimising the design of a 150-kg class satellite

The satellite platform was selected to enable the effective operation of the monitoring instruments on board. With the aim of keeping the constellation as simple and cost-effective as possible, several design options for integrating NanoCarb and SPEXone have been evaluated through trade-off studies. A catalogue of existing satellite platform products that address SCARBOn's challenges have also been developed to offer a range of options.

​A satellite constellation generates substantial amounts of data, and SCARBOn will be no exception. On‑board data compression could be necessary to reduce the volume of information that needs to be transmitted to the ground. This could help simplify data downlink, reduce ground‑segment requirements and maintain flexibility as data volumes increase. To support this approach, SCARBOn data transmission schemes have been tested and their efficiency demonstrated.

Artist’s view of a SCARBOn constellation satellite