An SwRI-led team detected carbon dioxide and hydrogen peroxide spectral signatures on Pluto’s largest moon Charon using Webb telescope observations (white), which extend the wavelength coverage of previous New Horizons flyby measurements (pink). The JWST and New Horizons data are consistent in the spectral shape and the strength of the absorption bands at short wavelengths of light; the offset in the absolute amount of scattered light can largely be attributed to differences in viewing geometries. These findings offer clues about the formation and evolution of Charon, shown in the background as imaged by New Horizons.