This work will answer the following science questions: does ION irradiation of lunar grains activate their surfaces in a manner that recreates the active surfaces and argon adsorption behavior…

This is a $523,539 federal grant awarded by the National Aeronautics and Space Administration (NASA) to the Southwest Research Institute (SwRI) to conduct research on the activation of lunar grain surfaces through ion irradiation. The research aims to understand the distribution of adsorption site energies for water and argon molecules on these artificially-weathered lunar grain surfaces and whether the results support or refute the proposed diurnal water cycle on the Moon. SwRI, a nonprofit research and development organization, has significant experience supporting government agencies through prime contracts and grants across various scientific and engineering disciplines. This grant is relevant to NASA's Solar System Workings program and does not have a set-aside designation, allowing SwRI to compete in a full and open competition. The research seeks to provide new laboratory measurements to address outstanding questions from recent lunar missions and observations regarding the behavior and abundance of volatiles on airless planetary bodies.

This work will answer the following science questions: does ION irradiation of lunar grains activate their surfaces in a manner that recreates the active surfaces and argon adsorption behavior understood to exist on the moon? What is the distribution of adsorption site energies for water and argon molecules on ION-irradiated lunar grain surfaces? Do the measured distributions of adsorption site energies support or refute a diurnal cycle for lunar water adsorption? We are presently in an ERA of reexamining the behavior and abundance of volatiles on the moon, mercury, ceres, phobos/diemos, and small bodies. New laboratory measurements are needed to answer outstanding questions from recent missions and telescopic observations, such as the proposed diurnal water cycle on the moon. Bernatowicz and podosek (1991) demonstrated the need to activate mineral surfaces immediately before conducting measurements of argon adsorption, but their technique is challenging, destroys the lunar rock being analyzed, and was too slow to access the highest energy adsorption sites. We proposed to demonstrate an improved technique that would provide higher fidelity measurements accessing the highest energy adsorption sites and reduce the amount of lunar sample required to perform the measurement. ION-irradiation experiments performed by the space weathering community have shown creation of nano-phase iron, amorphous rims, and other aspects of space weathered extraterrestrial samples, but no work has been published examining volatile adsorption behavior to such an artificially-weathered surface. We hypothesize that ION irradiation of grain surfaces will activate grain surfaces for lunar-like volatile adsorption and we will perform experiments to test this hypothesis. Should our hypothesis prove true, IT will open up a new and widely available technique for creating active grain surfaces. Such a technique would have the potential to revolutionize our ability to understand and predict the behavior of volatiles on rocky, airless bodies. We will then use our technique to measure the adsorption behavior of water on activated lunar grain surfaces and apply our results to the controversial diurnal water cycle that has potentially been observed on the moon. This work is relevant to solar system workings (SSW), and is not appropriate for any other NASA SMD roses program (see separate relevance section in the cover sheets).