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Abstract:

Carbonaceous chondrite meteorites, which include the sulfide-rich “Yamato-type” chondrites (CYs), have undergone a complex history of aqueous and thermal alteration and offer crucial insights into early outer solar system conditions. In this study, we evaluate thermal infrared (TIR) reflectance spectra of three CY chondrites. We observe a broad spectral plateau near 10 μm, a spectral signature that has been observed in remote observations of some primitive, low-albedo asteroids, including Jupiter Trojans. We compare our data to CY emissivity spectra, spectra of Fe-sulfide and olivine mixtures, and remote Jupiter Trojan observations and establish the plateau and low albedo are a result of a high content of fine-particulate Fe-sulfide of these meteorites. We therefore suggest that D- and P-type asteroids, like Jupiter’s Trojan asteroids, could have a high abundance of Fe sulfide on their surfaces as a potential result of aqueous alteration followed by dehydration, shedding light on the processes shaping the outer solar system.

Abstract:

Hydration on the Moon’s surface is widely detected in orbital datasets (e.g. M3 on Chandrayan-1), yet its abundance and physical form (-OH, H2O, frost, and/or ice) remain poorly constrained. The lunar surface is covered in regolith fines, which impacts local thermophysical conditions, obscures underlying volatiles and modifies detectable hydration bands. Our interpretation of hydration form and abundance on the lunar surface is further limited by existing experimental constraints of water-ice spectral behaviour at the regolith interface (photometric effects) and by the restriction of current orbital datasets to the near-infrared (< ~3 µm O–H stretching mode). We are developing a laboratory approach to quantify how dust layering, regolith maturity, grain size, composition, and ice abundance control the spectral expression of water-ice across the near- and mid-infrared (1.8–20 µm), with emphasis on the ~3 and 6 µm diagnostic regions. This poster presents a preliminary experimental set-up developed ahead of the full operation of a custom-built vacuum chamber, Polar Analogue of Dust Overlying Regolith–Ice (PANDOR-I), intended to simulate airless-body and cryogenic polar conditions. In this initial laboratory set-up, the sample compartment of a Bruker 70V Fourier Transform Infrared (FTIR) spectrometer is isolated using potassium bromide (KBr) windows to enable controlled, low-pressure (~0.2 mbar) reflectance measurements of anhydrous and hydrated analogue configurations to (i) characterise the spectral expression of hydration-related structure in the ~3 and 6 µm regions under regolith simulant fines, and (ii) provide benchmark spectra for direct comparison with a Mie–Hapke forward model (band shape,depth, and mixing trends) prior to cryogenic and airless body simulations with PANDOR-I. This preliminary work will establish an empirical reference for model validation and for designing the subsequent PANDOR-I cryogenic experiments, enabling a more robust interpretation of spectrally mixed hydration signatures in forthcoming lunar datasets.

Abstract:

Abstract Intermittently sunlit areas near the lunar south pole are estimated to harbor thermal conditions permitting long‐term stability of water ice and other volatiles. They are targets for future science and exploration missions due to the combination of sunlight availability for solar power generation, and the possibility for extraction of volatiles for scientific analysis and ISRU. We construct a geodatabase of spatially co‐registered remote sensing and thermal model results, and perform a probabilistic analysis to determine the likelihood of successfully landing and operating on such locations for a quadrangular study area that bounds the 80°S parallel. In addition to water ice thermal stability, we consider factors relevant for the operation of solar‐powered landed spacecraft: visibility to the Earth, visibility to the sun, and local slope. For two scenarios representing sets of most‐ and least‐constrained landing site requirements, we find that circular landing ellipse diameters of ∼0.9 and 2.6 km, respectively, would allow to target available compliant terrains with 100% success. We quantify the reduction in success probability with increasing landing ellipse size. Further, we explore the distributions of geometric properties of compliant areas, and identify three sites of interest that support large areas of compliant terrain: near De Gerlache crater, near Shackleton crater, and Mons Mouton (informally named as Leibnitz‐β massif). This study is provided to support planning for future lunar missions. Plain Language Summary Researchers have identified areas near the lunar poles that receive occasional sunlight and could keep water ice and other resources stable over a long period of time. These spots are valuable for future lunar missions since they could provide solar power and possibly resources such as water for scientific study and on‐site use. To assess potential landing sites in the south polar region, we created a database combining remote sensing and thermal data set, then used it to calculate the likelihood of successful landing on accessible terrains with stable water ice conditions from the 80°S to the South Pole. The study looked at factors critical for solar‐powered landers: the terrain's visibility to Earth (for communication), sunlight access, and the slope of the ground. We analyzed two scenarios with different landing precisions. We found that landing areas with diameters of about 0.9 and 2.6 km could ensure a 100% success rate under the most‐ and least‐constrained scenarios, respectively. Larger landing areas decreased the success probability. We also mapped the physical characteristics of ideal areas and highlighted three promising locations near De Gerlache crater, Shackleton crater, and Mons Mouton. Key Points We identify intermittently sunlit areas that permit long‐term stability of sub‐surface water ice, and accessible by landed missions “Compliant terrains” in two scenarios range from 13,071 km² (least constrained) to 290 km² (most constrained) in the south polar region For areas ≥80°S, we recommend sub‐km landing precision for missions with success criteria involving exploration of lunar polar water ice

Abstract:

Research into compositions of small bodies and planetary surfaces, such as asteroids, is key to understanding the origin of water and organics on Earth [1], as well as placing constraints on planetary dynamics and migration models [2] that can help understand how planetary systems around other stars may form and evolve. Compositional estimates can be found with thermal infrared (TIR; 5-25μm) spectroscopy, as the TIR region is rich in diagnostic information and can be used in remote sensing observations and laboratory measurements. However, TIR spectra of the same material may appear differently depending on several factors, such as particle size, surface roughness, porosity etc. This work quantifies the changes in spectral morphology (i.e., shapes and depths of spectral features) as particle size transitions from fine (90%), at several size fractions, aimed to be