Instrumental development of NanoCarb, a new spectro-imaging sensor

International audienceEstimating emissions of the main greenhouse gases (such as CO2 and CH4) is a challenge in studying climate change. The European project called SCARBO, which involves several partners, aims at evaluating the feasibility of a low-cost constellation of small satellites onboarding small instruments, which could be capable of quantifying greenhouse gases. In this context, we propose NanoCarb, a miniature snapshot Fourier-transform imaging spectrometer concept dedicated to the measurement of two greenhouse gases: CO2 and CH4. Its compact design makes it a good candidate for small satellites. It is based on a multi-channel architecture which provides a sparse interferometric sampling strategy. This multi-channel design only involves two specific optical components: a microlens array and an interferometric plate, which is a stepcase phase plate. We have developed and assembled two NanoCarb prototypes which have been experimentally validated through a dedicated airborne campaign. This paper focuses on the design and laboratory calibrations of the two prototypes. The tests include both imaging and spectral features of the instruments. An adequate laboratory calibration is essential to process the data acquired by the prototypes during the airborne campaign. Experimental results show the good quality of the prototypes

NanoCarb spaceborne miniaturized GHG sensor: first experimental results

International audienceThe Space CARBon Observatory (SCARBO) European program aims at assessing the monitoring of anthropogenic emissions of Green House Gas (GHG) with the uncovered goal of a sub-daily revisit of the Earth at an affordable cost. One of the main project scopes is the feasibility study of a hybrid constellation including both high accuracy reference missions (Copernicus CO2M or CNES MicroCarb mission) and 24 small-satellites onboarding innovative miniaturized payloads. The key GHG-sensor of the smallsat constellation is the NanoCarb concept, an unprecedently kilogram-class Fourier Transform imaging spectrometer. We are reporting here some preliminary experimental results from a demonstration airborne campaign. A low cost, 2-bands prototype designed for CO2 and CH4 measurement has been developed then integrated over a Falcon-20 from SAFIRE, jointly to SPEX aerosol sensor from SRON. During October 2020, we flew over Spain, Italy, and towards Poland from Francazal airport in Toulouse, France. Even if we did not have the opportunity to flight over a powerplant, a lot of data has been acquired and are being processed. After presented the instrument, mission and data products, we assess the data quality and the reliability of the model. We derive finally an expected sensitivity over CO2 and CH4 columns according to the background respectively about 1.5-2.5% and 5%. We finally demonstrate the operability of this first TRL5 prototype of NanoCarb