Laboratory spectra (modified from T. Suhasaria et al. 2025) of CO₂ ice condensed on a silicate-rich, meteorite simulant layer (70 K) and amorphous H₂O ice (“ASW”) deposited on a meteorite simulant layer (70 K). These laboratory spectra are compared to G395M reflectance data of Ariel trailing and Umbriel trailing, converted to absorbance (–log(reflectance)) and offset vertically for clarity. Dashed lines highlight spectral features identified in the laboratory data near 4.383 and 4.393 μm. The 4.383 μm peak is offset from the Ariel and Umbriel data, but the 4.393 μm peak provides a potentially useful match to Umbriel’s broad ¹³CO₂ feature that warrants study in future work.