LOAC (Light Optical Aerosols Counter) is an on-board sensor, suspended under the capsule, designed to study particles in the upper atmosphere using multi-refraction laser analysis.

Operating autonomously on battery power, it characterizes the nature and density of aerosols (water vapor, sand, volcanic ash, fine particles, meteorite dust and satellite debris).

Developed by the LPC2E (Laboratory of Physics and Chemistry of the Environment and Space), the LOAC is essential for understanding the dispersion of Saharan particles, the impact of volcanic eruptions on the climate, and the behavior of residues from atmospheric re-entries of satellites.