A company specialising in earth observation satellites is developing a new multispectral sensor designed to measure air quality and greenhouse gas concentrations. Before sending it into orbit, the company needs to ensure that it performs under real conditions, particularly in terms of sensitivity and calibration.

The sensor is embedded in a stratospheric balloon and deployed at an altitude of 25 km. This position is ideal, as it is above 98% of the atmosphere, eliminating most atmospheric interference while remaining close enough to the Earth to validate the resolution and accuracy of the measurements.