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1. The reactivity of experimentally reduced lunar regolith simulants: Health implications for future crewed missions to the lunar surface

   https://doi.org/10.1111/maps.14228  

   Hendrix, Donald A; Catalano, Tristan; Nekvasil, Hanna; Glotch, Timothy D; Legett, Carey; Hurowitz, Joel A (June 2024, Meteoritics & Planetary Science)

   Abstract Crewed missions to the Moon may resume as early as 2026 with NASA's Artemis III mission, and lunar dust exposure/inhalation is a potentially serious health hazard that requires detailed study. Current dust exposure limits are based on Apollo‐era samples that spent decades in long‐term storage on Earth; their diminished reactivity may lead to underestimation of potential harm that could be caused by lunar dust exposure. In particular, lunar dust contains nanophase metallic iron grains, produced by “space weathering”; the reactivity of this unique component of lunar dust is not well understood. Herein, we employ a chemical reduction technique that exposes lunar simulants to heat and hydrogen gas to produce metallic iron particles on grain surfaces. We assess the capacity of these reduced lunar simulants to generate hydroxyl radical (OH*) when immersed in deionized (DI) water, simulated lung fluid (SLF), and artificial lysosomal fluid (ALF). Lunar simulant reduction produces surface‐adhered metallic iron “blebs” that resemble nanophase metallic iron particles found in lunar dust grains. Reduced samples generate ~5–100× greater concentrations of the oxidative OH* in DI water versus non‐reduced simulants, which we attribute to metallic iron. SLF and ALF appear to reduce measured OH*. The increase in observed OH* generation for reduced simulants implies high oxidative damage upon exposure to lunar dust. Low levels of OH* measured in SLF and ALF imply potential damage to proteins or quenching of OH* generation, respectively. Reduction of lunar dust simulants provides a quick cost‐effective approach to study dusty materials analogous to authentic lunar dust. 

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2. Historical Audio Search and Preservation: Finding Waldo Within the Fearless Steps Apollo 11 Naturalistic Audio Corpus

   https://doi.org/10.1109/MSP.2023.3237001  

   Chandra Shekar, Meena M.; Hansen, John H.L. (May 2023, IEEE Signal Processing Magazine)

   Apollo 11 was the first manned space mission to successfully bring astronauts to the Moon and return them safely. As part of NASA’s goal in assessing team and mission success, all voice communications within mission control, astronauts, and support staff were captured using a multichannel analog system, which until recently had never been made available. More than 400 personnel served as mission specialists/support who communicated across 30 audio loops, resulting in 9,000+ h of data. It is essential to identify each speaker’s role during Apollo and analyze group communication to achieve a common goal. Manual annotation is costly, so this makes it necessary to determine robust speaker identification and tracking methods. In this study, a subset of 100hr derived from the collective 9,000hr of the Fearless Steps (FSteps) Apollo 11 audio data were investigated, corresponding to three critical mission phases: liftoff, lunar landing, and lunar walk. A speaker recognition assessment is performed on 140 speakers from a collective set of 183 NASA mission specialists who participated, based on sufficient training data obtained from 5 (out of 30) mission channels. We observe that SincNet performs the best in terms of accuracy and F score achieving 78.6% accuracy. Speaker models trained on specific phases are also compared with each other to determine if stress, g-force/atmospheric pressure, acoustic environments, etc., impact the robustness of the models. Higher performance was obtained using i-vector and x-vector systems for phases with limited data, such as liftoff and lunar walk. When provided with a sufficient amount of data (lunar landing phase), SincNet was shown to perform the best. This represents one of the first investigations on speaker recognition for massively large team-based communications involving naturalistic communication data. In addition, we use the concept of “Where’s Waldo?” to identify key speakers of interest (SOIs) and track them over the complete FSteps audio corpus. This additional task provides an opportunity for the research community to transition the FSteps collection as an educational resource while also serving as a tribute to the “heroes behind the heroes of Apollo.” 

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3. 3D printable regolith filled shape memory vitrimer composite for extraterrestrial application

   https://doi.org/10.1177/00219983241274544  

   Gyabaah, Kingsley Yeboah; Konlan, John; Tetteh, Obed; Jahan, Maryam; Jackson, Enrique; Mensah, Patrick; Li, Guoqiang (October 2024, Journal of Composite Materials)

   This study investigates a neoteric approach in manufacturing lunar regolith-filled shape memory vitrimer (SMV) composites for extraterrestrial applications. A SMV with robust mechanical properties was combined with locally available lunar regolith to form a composite material. Fourier Transfer Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), and X-ray fluorescence (XRF) were used to characterize the resin, the regolith simulant, and the prepared SMV-regolith composites. We explored conventional synthesis as well as 3D printing methods for manufacturing the composite. Glass fabric-reinforced laminated composites were also prepared to evaluate the impact tolerance and damage healing efficiency. Compressive strength, flexural strength, and impact resistance of the composite were tested at both room and elevated temperatures. A compressive strength of 96.0 MPa and 5.4 MPa were recorded for composite with 40 wt% regolith ratio at room and elevated temperatures, respectively. The glass fabric reinforced SMV-regolith laminate exhibited a bending strength of 232.7 MPa, good impact tolerance under low-velocity impact test, and good healing efficiency up to two damage healing cycles. The 3D printed SMV-regolith composite using a liquid crystal display (LCD)-based printer exhibited a good thermomechanical property with a compressive and tensile strength of 139.16 MPa and 13.99 MPa, respectively, and a good shape memory effect. However, the LCD-based printing using vat-photopolymerization limits the size of the printed samples. Nonetheless, this study shows that utilization of regolith to form advanced composite is possible. SMV regolith composite is a promising material for lunar base applications due to its simple manufacturing process, excellent mechanical properties, and low energy consumption. 

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4. Absence of a long-lived lunar paleomagnetosphere

   https://doi.org/10.1126/sciadv.abi7647  

   Tarduno, John A.; Cottrell, Rory D.; Lawrence, Kristin; Bono, Richard K.; Huang, Wentao; Johnson, Catherine L.; Blackman, Eric G.; Smirnov, Aleksey V.; Nakajima, Miki; Neal, Clive R.; et al (August 2021, Science Advances)

   Determining the presence or absence of a past long-lived lunar magnetic field is crucial for understanding how the Moon’s interior and surface evolved. Here, we show that Apollo impact glass associated with a young 2 million–year–old crater records a strong Earth-like magnetization, providing evidence that impacts can impart intense signals to samples recovered from the Moon and other planetary bodies. Moreover, we show that silicate crystals bearing magnetic inclusions from Apollo samples formed at ∼3.9, 3.6, 3.3, and 3.2 billion years ago are capable of recording strong core dynamo–like fields but do not. Together, these data indicate that the Moon did not have a long-lived core dynamo. As a result, the Moon was not sheltered by a sustained paleomagnetosphere, and the lunar regolith should hold buried 3 He, water, and other volatile resources acquired from solar winds and Earth’s magnetosphere over some 4 billion years. 

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5. 3GPP Mobile Telecommunications Technology on the Moon

   https://doi.org/10.1109/AERO55745.2023.10115746  

   Edwards, Bernard; Wagner, Raymond; Zemba, Michael; Millard, Wesley; Braham, Stephen; Gifford, Kevin; Somerlock, Oscar (March 2023, IEEE)

   Under NASA’s Artemis program, NASA is planning to send astronauts back to the Moon in the next couple of years. Near term missions will be analogous but much more sophisticated versions of the last couple of Apollo missions. However, unlike Apollo, this time NASA intends to put the infrastructure in place to support long term human presence and eventual industrialization of the Moon. To make this vision a reality, NASA plans to collaborate with commercial and international partners as much as possible as opposed to developing, building, and operating equipment on its own. Lunar infrastructure will eventually be built over time by many organizations, public and private, to support sustained human exploration, science, and industrial activities. Obviously, this vision for the future will be impossible without a robust lunar communications and navigation system that can support many users with varying degrees of services. On Earth, most people are very familiar with the 3rd Generation Partnership Project (3GPP) 5G mobile telecommunications technology. NASA’s Space Technology Mission Directorate and NASA’s Space Communications and Navigation office would like to see a lunar communications and navigation network with similar capabilities to the cellular communication networks most of us enjoy today. Building such a network will require participation by many organizations. This paper will provide an overview of NASA’s interest in using 5G and beyond on the lunar surface; it will also describe current work based on 3GPP standards within NASA or funded by NASA, such as Nokia’s upcoming Tipping Point demonstration of 4G / LTE on the lunar surface. 

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