Hydrogen ice within lunar polar craters

Abstract

We might have overlooked the widespread presence of methanol on the Moon and hydrogen ice within lunar polar craters. Here we show that (1) US Moon Mineralogy Mapper (M3) cannot distinguish between hydroxyl radicals from lunar water and hydroxyl groups from lunar methanol because the absorption strengths of the two are all 2.9 μm, and there are no established methods to distinguish them using the 2.9 μm band. Water ice within lunar polar craters is worthy of renewed investigation. (2) The ‘surficial water’ illogically appears at the lunar equator based on M3 spectral detection, seriously shaking the credibility of M3 spectral data analysis. (3) Methanol and water brought about by the interstellar methanol ice react in lunar carbon-rich regolith using Ce/Cu/Zn–Al catalysts to produce massive molecular hydrogen. This molecular hydrogen escapes into the lunar exosphere and is transported to lunar cold traps, forming brown-black solid molecular hydrogen (hydrogen ice) that appears in snowflake patterns at the lowest temperature within lunar polar craters. (4) The author concludes with a model of the physico-chemical process chains on the lunar surface, which systematically elucidates the mechanism of lunar hydrogen ice formation. (5) Hydrogen ice within lunar polar craters can become a fuel base for interplanetary flight.