Analysis of Lunar Boulder Tracks: Implications for Trafficability of Pyroclastic Deposits

In a new era of lunar exploration, pyroclastic deposits have been identified as valuable targets for resource utilization and scientific inquiry. Little is understood about the geomechanical properties and the trafficability of the surface material in these areas, which is essential for successful mission planning and execution. Past incidents with rovers highlight the importance of reliable information about surface properties for future, particularly robotic, lunar mission concepts. Characteristics of 149 boulder tracks are measured in Lunar Reconnaissance Orbiter Narrow Angle Camera images and used to derive the bearing capacity of pyroclastic deposits and, for comparison, mare and highland regions from the surface down to ~5‐m depth, as a measure of trafficability. Results are compared and complemented with bearing capacity values calculated from physical property data collected in situ during Apollo, Surveyor, and Lunokhod missions. Qualitative observations of tracks show no region‐dependent differences, further suggesting similar geomechanical properties in the regions. Generally, bearing capacity increases with depth and decreases with higher slope gradients, independent of the type of region. At depths of 0.19 to 5 m, pyroclastic materials have bearing capacities equal or higher than those of mare and highland material and, thus, may be equally trafficable at surface level. Calculated bearing capacities based on orbital observations are consistent with values derived using in situ data. Bearing capacity values are used to estimate wheel sinkage of rover concepts in pyroclastic deposits. This study's findings can be used in the context of traverse planning, rover design, and in situ extraction of lunar resources

Using Boulder Tracks as a Tool to Understand the Bearing Capacity of Permanently Shadowed Regions of the Moon

Permanently shadowed regions (PSRs) are abundant at the lunar poles. They experience no direct sunlight and reach temperatures as low as 30 K. PSRs are of interest as evidence suggests that some may contain water ice (H2O/OH‐), which could provide a record of the evolution of volatiles in the inner solar system. This water ice is also a critical resource for life‐support systems and rocket propellant. A better understanding of mechanical properties of PSR regolith, such as its bearing capacity, will help optimize the design of future exploration rovers and landers. Thirteen boulder tracks were identified on the edge of, or inside, south polar lunar PSR enhanced imagery and used to estimate the strength of the PSR regolith at latitudes of 70° to 76° in sites with maximum annual temperatures of 65 to 210 K. PSR boulder track features are similar to those observed in highland, mare, and pyroclastic regions of the Moon, implying similar properties of the regolith. Measured features were used to estimate bearing capacity for PSR regolith at depths of ~0.28 to 4.68 m. Estimated bearing capacity values suggest that these PSRs may be somewhat stronger than highland and mare regions at depths of 0.28 to 1.00 m. Bearing capacity in these PSRs is statistically the same as those in other regions of the Moon at depths of 1.00 to 2.00 m. The results of this study can be used to infer bearing capacity as one measure for the trafficability of lower‐latitude PSRs of the type measured here

Human-assisted Sample Return Mission at the Schrödinger Basin, Lunar Far Side, Using a New Geologic Map and Rover Traverses

The Schrödinger basin on the south polar lunar far side has been highlighted as a promising target for future exploration. This report provides a high-resolution geologic map in the southwest peak-ring (SWPR) area of the Schrödinger basin, emphasizing structural features and detailed mapping of exposed outcrops within the peak ring. Outcrops are correlated with mineralogical data from the Moon Mineralogical Mapper instrument. Geologic mapping reveals a complex structural history within the basin through a system of radially oriented faults. Further, the geologic map shows both faulted and magmatic contacts between peak-ring mineralogies, providing both structural and magmatic context for understanding lunar crustal evolution and polar region processes. To investigate these relationships and address key scientific concepts and goals from the National Research Council (NRC) report, we propose three traverse paths for a robotic sample return mission in the SWPR area. These traverses focus on addressing the highest priority science concepts and goals by investigating known outcrops with diverse mineralogical associations and visible contacts among them. Coinciding with the preparation for the 2024 Artemis III mission, NASA is increasing the priority of robotic exploration at the lunar south pole before the next crewed mission to the Moon. Through mapping the Schrödinger SWPR, we identified the extent of different lunar crustal mineralogies, inferred their geologic relationships and distribution, and pinpointed traversable routes to sample spectrally diverse outcrops and outcrop-derived boulders. The SWPR region is therefore a promising potential target for future exploration, capable of addressing multiple high-priority lunar science goals

Current accounts of antimicrobial resistance: stabilisation, individualisation and antibiotics as infrastructure.

Antimicrobial resistance (AMR) is one of the latest issues to galvanise political and financial investment as an emerging global health threat. This paper explores the construction of AMR as a problem, following three lines of analysis. First, an examination of some of the ways in which AMR has become an object for action-through defining, counting and projecting it. Following Lakoff's work on emerging infectious diseases, the paper illustrates that while an 'actuarial' approach to AMR may be challenging to stabilise due to definitional and logistical issues, it has been successfully stabilised through a 'sentinel' approach that emphasises the threat of AMR. Second, the paper draws out a contrast between the way AMR is formulated in terms of a problem of connectedness-a 'One Health' issue-and the frequent solutions to AMR being focused on individual behaviour. The paper suggests that AMR presents an opportunity to take seriously connections, scale and systems but that this effort is undermined by the prevailing tendency to reduce health issues to matters for individual responsibility. Third, the paper takes AMR as a moment of infrastructural inversion (Bowker and Star) when antimicrobials and the work they do are rendered more visible. This leads to the proposal of antibiotics as infrastructure-part of the woodwork that we take for granted, and entangled with our ways of doing life, in particular modern life. These explorations render visible the ways social, economic and political frames continue to define AMR and how it may be acted upon, which opens up possibilities for reconfiguring AMR research and action

The Vibrational Structure of HCN between 9000 and 19000cm−119 000 cm^{-1}.

$^{1}$ J.A. Bentley, J. -P. Brunet. R.E. Wyatt. R.A. Friesner, C. Leforestier, Chem. Phys. Lett., 161. 393 (1989) $^{2}$ J.N. Murrell, S. Carter, L.O. Halonen. J. Mol. Spectrosc., 93. 307 (1982)Author Institution: Department of Chemistry., University of California. Santa Sarbara.Stimulated emission pumping spectra of HCN in its ground electronic state have been measured using a pulsed tunable Argon fluoride laser with a frequency doubled pulsed dye laser. Sixty seven vibrational states between 8900 and $18 900 cm^{-1}$ have been observed. Eighty percent of the States can be described within a traditional normal mode picture. A full set of anharmonic vibrational constants was derived unifying the SEP data reported here with previous infrared data. Twenty percent of the states could not be explained by the normal mode picture and a systematic analysis was performed to show that only a few of the unexplained states might be a linear superposition of $zero^{th}$ order normal mode HCN states. Since most of the unexplained states cannot be constructed out of normal mode HCN states, it is suggested that ``isomerizing'' delocalized vibrational states are playing a role in the observed vibrational structure. Direct comparison is possible with ab initio vibrational structure $calculations^{1}$ on the only available three dimensional potential energy $surface^{2}$. The experimental results show clearly that the true potential has a much higher barrier to isomerization. The present state of experimental characterization of the HCN/HNC systems should be good enough to derive a quantitatively accurate potential energy surface for this prototypical isomerization reaction

Stimulated Emission Pumping Spectroscopy of Acetaldehyde: The Influence of Molecular Structure on the High Resolution Vibrational Spectrum

Author Institution: Department of Chemistry, University of California at Santa BarbaraABSTRACT: High resolution Stimulated Emission Pumping (SEP) spectra of acetaldehyde in a pulsed molecular beam have been recorded over a wide range of final ground state (SO) energies ($0.4000 cm^{-1}$). One of a group of molecules that undergo similar $\pi^{+}\leftarrow n$ C-type transitions, acetaldehyde is distinguished by extremely complex spontaneous emission and SEP spectra even under cold conditions. We suggest that the increased complexity arises from a structurally mediated coupling of vibrational modes via the methyl rotor. This coupling leads to a greatly reduced intensity in the strong progression anticipated in the $C=O$ stretching vibration from a Franck-Condon factor argument, and also results in an increase in the intensity of a manifold of other, normally less active, modes