SPEXone for CO2M

SPEXone is a compact multi-angle spectropolarimeter for the quantification of atmospheric aerosol. This provides a light-path correction for accurate CO₂ quantification. SPEXone is a candidate instrument for ESA’s two CO2M satellites to be launched in 2026. The instrument is a copy of the SPEXone instrument for NASA’s PACE, but with an increased across-track swath of the telescopes of 250 km on the ground. The telescopes look 50 and 20 degrees forward and backward, and straight down (nadir). Special Polarization Modulation Optics modulate the spectral intensity according the state of linear polarization. Each spectrum is then split in two polarizations and the ten modulated spectra are created in the spectrometer and projected on one CMOS detector array.