Художественный рендеринг китайского посадочного модуля Song 5 на Луне. Исследователи обнаружили воду в ударных стеклянных шариках в лунном грунте Чанъэ-5. Считается, что эти стеклянные бусины представляют собой новый резервуар для воды на Луне, отражающий динамический обмен воды, получаемый солнечным ветром. Это открытие предполагает, что эти шарики играют роль буфера в круговороте воды на поверхности Луны. Кредит: CNSA/НАСА
Лунные поверхностные воды привлекли значительное внимание из-за их потенциала для использования ресурсов на месте будущими миссиями по исследованию Луны и другими космическими миссиями.
Ныне профессор Института географии и геофизики (IGG) Китайской академии наук (CAS). Исследовательская группа под руководством Чена Ху обнаружила немного воды в ударных стеклянных шариках в лунном грунте Чанъэ-5 (CE5). .
Подробные исследования показывают, что эти стеклянные шарики могут быть новым резервуаром для воды на Луне, регистрирующим динамический вход и выход воды, полученной из солнечного ветра, и выступающей в качестве буфера для круговорота воды на поверхности Луны.
Работа будет опубликована сегодня (27 марта) в журнале 
A schematic diagram of the lunar surface water cycle associated with impact glass beads Credit: Prof. Sen Hu’s group
Many lunar missions have confirmed the presence of structural water or water ice on the Moon. There is little doubt that most of the Moon’s surface harbors water, though the amount is much less than on Earth.
Surface water on the Moon displays diurnal cycles and loss to space, indicating that there should be a hydrated layer or reservoir at depth in lunar soils to sustain the retention, release, and replenishment of water on the surface of the Moon. However, previous studies of water inventory of fine mineral grains in lunar soils, impact-produced agglutinates, volcanic rocks, and pyroclastic glass beads have been unable to explain the retention, release, and replenishment of water on the surface of the Moon (i.e., the lunar surface water cycle). Therefore, there must be a yet-unidentified water reservoir in lunar soils that has the capacity to buffer the lunar surface water cycle.
Doctoral student Huicun He, under the guidance of Prof. Sen Hu, proposed that impact glass beads, a ubiquitous component in lunar soils with an amorphous nature, were a potential candidate for investigation of the unidentified hydrated layer or reservoir in lunar soils.
She systematically characterized the petrography, major element composition, water abundance, and hydrogen isotope composition of the impact glass beads returned by the CE5 mission, aiming to identify and characterize the missing water reservoir on the Moon’s surface.
The CE5 impact glass beads have homogeneous chemical compositions and smooth exposed surfaces. They are characterized by water abundance up to about 2,000 μg.g-1, with extreme deuterium-depleted characteristics. The negative correlation between water abundance and hydrogen isotope composition reflects the fact that water in the CE5 impact glass beads comes from solar winds.
The researchers also analyzed water abundance along six transects in five glass beads, which showed the hydration profiles of solar wind-derived water. Some glass beads were overlapped by a later degassing event. The impact glass beads acted as a sponge for buffering the lunar surface water cycle. The researchers estimate that the amount of water contributed by impact glass beads to lunar soils varies from 3.0 × 1011 kg to 2.7 × 1014 kg.
“These findings indicate that the impact glasses on the surface of the Moon and other airless bodies in the solar system are capable of storing solar wind-derived water and releasing it into space,” said Prof Hu.
Reference: “A solar wind-derived water reservoir on the Moon hosted by impact glass beads” 27 March 2023, Nature Geoscience.
DOI: 10.1038/s41561-023-01159-6
The study was a collaboration with Nanjing University, The Open University, The Natural History Museum, The University of Manchester, and the University of Science and Technology of China.
