Calibration of MAJIS (Moons and Jupiter Imaging Spectrometer): V. Validation with mineral samples and reference materials.

This article focuses on the ground calibration and performance assessment of MAJIS (Moons and Jupiter Imaging Spectrometer), an imaging spectrometer aboard ESA's JUICE (JUpiter and ICy Moons Explorer) spacecraft launched in April 2023. MAJIS operates across the visible to mid-infrared range (0.5–5.54 μm) and underwent extensive calibration in 2021 using natural mineral samples and synthetic reference materials to evaluate its spectral and spatial capabilities under conditions simulating future observations. The study finds that MAJIS meets most spectral and spatial performance requirements, accurately detecting spectral bands and shapes across its range, though stray light notably affects measurements between 0.6 and 0.9 μm (and up to 1.3 μm in some cases), causing spectral contrast reductions up to 60% and wavelength shifts of 1–2.5 nm that vary with viewing conditions and field of view position. Additionally, MAJIS demonstrated the ability to generate hyperspectral images of mineral samples, confirming its spatial resolution aligns with design expectations. These calibration results provide a baseline for interpreting MAJIS data during the JUICE mission's cruise and orbital phases around Jupiter and its icy moons.