MELODY

MELODY Moon multisEnsor and LabOratory Data analYsis

In detail

While 2019 marked the 50th anniversary of the first human landing on the Moon, the systematic and capillary robotic exploration of our natural satellite is an indispensable step for future human expansion in our Solar System. Several space agencies and private companies are developing strategies to bring humans back to the Moon by the end of this decade. This new international race is driven by scientific, technological and economic interests and requires an in-depth understanding of the lunar context to select the best landing sites: for example, it is necessary to gather an excellent knowledge of geochemistry and surface mineralogy not only on a regional scale but also on a very local scale, a necessary requirement to ensure the possibility of extracting oxygen and water from rocks. Access to and exploitation of lunar resources are a key component of any future space exploration effort in cislunar space and beyond. Nowadays, human lunar exploration involves a permanent and widespread presence on the surface, which in turn requires the ability to collect, transform and use the natural resources present on the spot: in one acronym, the so-called In-Situ Resource technology Utilization (ISRU). The general objective of the PRIN INAF "MELODY" project is to achieve a broader understanding of our Moon by combining surface and subsurface data analysis and laboratory characterization of the lunar environment. The MELODY project aims to perform an unprecedented analysis of an "aggregate dataset" consisting of maps of geochemical and gravitational anomalies, and mineralogical data, obtained from orbital missions in recent decades, which would allow us to highlight the emergence of homogeneous units with respect to different variables, not necessarily evident in individual datasets. The analysis of lunar subsurface radar data, which unlike the previous datasets have a limited coverage, will be performed on specific regions of interest by applying updated techniques that have recently been applied to the MARSIS radar in orbit around Mars and to the data lunar radars acquired in situ from Chinese rovers. In parallel, laboratory analyzes will be carried out on several lunar regolith simulants, which are key to characterize the dielectric environment and therefore the electromagnetic modeling. Finally, another novelty of our proposal concerns the possibility of carrying out laboratory measurements that are still missing on a few lunar meteorite samples, to be purchased on purpose. Unlike moon rocks returned by astronauts, lunar meteorites can come from virtually anywhere on the lunar surface, including the farside. Thus, this analysis could place these meteorite specimens in the global geochemical and petrological context of our natural satellite. These activities are grouped into three scientific work packages: WP1, WP2 and WP3. The main objectives of the scientific WPs are: 1) Identification and mapping of homogeneous local scale units with respect to different lunar datasets, 2) Analysis and modeling of the lunar radar scattering returned by ground penetrating radars, with relative laboratory characterization of the lunar dielectric environment, and 3) Mineralogical, petrological and geochemical characterization of some lunar meteorites. The areas and activities of each WP are described below: WP1 (Surface science): The purpose of this WP is to carry out an innovative analysis of publicly available lunar datasets concerning: mineralogy, geochemistry and possibly gravimetry, combining them into a single "aggregate" dataset to be classified using multivariate statistical techniques in order to highlight surface units homogeneous in which correlations emerge between the surface and the deep interior that can be quantified. Due to time constraints, this analysis is performed only on a few specific regions of interest (RoI) defined as priority on the basis of the lunar exploration roadmap and the current state of the analysis of the lunar data (in this case: Mare Ingenii, Von Karmann crater, Klaproth/Casatus craters). WP2 (Subsurface geophysics): The purpose of this WP is twofold: 1) re-analysis and modeling of lunar data obtained from experiments with low-frequency radar echo sounders that orbited the Moon in the past, in the light of modern processing techniques, and 2) characterization, in terms of dielectric permittivity, of several lunar regolith simulants representative of both lunar highlands and maria. These laboratory measurements, unique of their kind, aim to adequately constrain the dielectric assumptions used in radar data simulations. WP3 (Analysis of lunar meteorites): The WP3 couples mineralogical / petrographic and geochemical data with spectroscopic analyzes on at least 4 lunar meteorite samples, purchased for this project and representative of different lunar lithological characteristics. This research has a double implication, namely: 1) to directly compare spectral and hyperspectral data with direct mineralogical data (SEM, XRD), 2) to provide a complete geochemical, mineralogical and isotopic characterization on at least one of these lunar meteorites. The WP3 also provides support to WP2 in the mineralogical (XRD) and granulometric characterization of lunar regolith simulants.