The detection of chloride salts along Curiosity's traverse is of significant interest for astrobiology, as these salts may help protect organic molecules from radiation-induced degradation on the Martian surface. This suggests that chloride-rich environments could represent promising targets for future investigation. However, in situ analyses of Martian rocks and soils conducted by the Sample Analysis at Mars (SAM) instrument suite onboard the Curiosity rover, and likely by the GC–MS instruments onboard the Viking landers, have shown that chlorine-bearing phases, such as perchlorates and chlorates, can react with organic molecules during thermal extraction from natural solid samples. The thermal decomposition of these oxidants can generate organochlorine compounds from indigenous Martian organic matter. Given the known reactivity of perchlorates and chlorates during pyrolysis–GC–MS, it is therefore important to assess whether chloride salts may also influence the detection of organic molecules. Here, we present a systematic laboratory study investigating the influence of three chloride salts likely present on Mars (MgCl₂, CaCl₂, and NaCl) on the detection of organic molecules by pyrolysis–GC–MS, as performed by the Viking and MSL missions, and planned for the upcoming ExoMars mission. Our results show that salt degradation, particularly through the release of hydrogen chloride, alters the nature, abundance, and distribution of pyrolysis products. Furthermore, we demonstrate that organic molecules and chlorides may act as precursors to the chlorohydrocarbons already detected on Mars. These findings indicate that chloride salts can significantly influence both the detectability and interpretation of organic compounds in Martian samples.
Transverse aeolian ridges (TARs) represent significant bedforms in the Utopia Planitia region, which encompasses the landing site of China's Zhurong rover. The morphology offers insights into the interactions between Mars's thin atmosphere and its surface, highlighting implications for geological and palaeoclimatic evolution. However, although TARs typically span from several meters to tens of meters, their overall scale is considerably smaller than that of typical aeolian features like dunes and yardangs, unevenly distributed, and locally grouped, which has constrained attempts to connect their spatial arrangements and morphometric characteristics to broader regional geomorphology. This work presents the development of an automated deep learning-based TAR-detection framework for Utopia Planitia, and describes the integration of the resulting inventory with complementary automated crater mapping and quantitative spatial analyses. By employing transfer learning together with a deep neural network and using 15 high-resolution HiRIC orthorectified images that encompass the Tianwen-1 landing area, we successfully identify approximately 420,000 TARs. This effort culminates in the creation of what we believe to be the most extensive database of TARs and craters for Utopia Planitia (TAR424031, LU170671). Their length-to-width ratio stabilizes around 3:1, and the frequency distributions of length, width, perimeter, and area are roughly log-normal. The density patterns linked to impact craters provide additional constraints on the formation mechanisms for TARs in Utopia Planitia. This research establishes a scalable foundation for detailed global TAR mapping, facilitating the reconstruction of Martian climate history and enhancing Mars global climate models.
To guide development of lunar microwave processing on the Moon, we measured the high-temperature basic dielectric properties (ε' and ε″) of 17 lunar simulants and related materials. The measurements were performed using the cavity perturbation method over a temperature range between room temperature to 1000 °C, or higher, and giving the real and imaginary components of permittivity at six frequencies. All of the ε' and ε″ measurements at the frequency of 2466 MHz have been scaled to a constant density, 1.75 g/cm3. Here the data are presented as graphs chosen to aid analysis within and across simulant groups. To gain additional insight into the processes happening at the elevated temperatures in the dielectric measurements, heat capacity data was obtained using differential scanning calorimetry (DSC) on several of the simulant materials.Over the frequency range 397 MHz – 2985 MHz a material's behavior does not greatly change, as compared to the scale of differences observed between lunar mare and highland simulants at high temperatures. As liquidus temperatures are reached both permittivity and dielectric loss rise rapidly, helping to explain thermal runaway during microware heating. Our data show that less than a few weight % of many non-lunar minerals, and the use of mixtures in simulants can affect the dielectric behavior at higher temperatures. A comparison of our results with published dielectric data for Apollo samples and with remote sensing of the Moon supports the conclusion the simulants and lunar material at room temperature have very similar dielectric values.
Dust devils are intense, convectively driven vortices observed on Earth and Mars that can loft surface particulates and dust. Classical analytical descriptions from the Rankine combined vortex and the Burgers–Rott solutions to recent stream-function formulations, assumes a cylindrical core of constant radius. This assumption, while mathematically convenient, but geometrically incompatible with the inverted-cone morphology established by terrestrial field observations, Mars Science Laboratory, Mars-2020, in-situ measurements, and high-resolution large-eddy simulations. Conical vortex solutions have been obtained by Kurgansky (2025) for a slender baroclinic cone. Here we construct an inviscid, axisymmetric, steady-state stream-function model where core boundary is a height-dependent linear surface, c(z)=c0+αz, parametrized by the ground-level core radius c0 and dimensionless cone-slope parameter α=dc/dz. Introducing the core-relative coordinate η(r,z)≡r−c(z), we derive a closed-form Stokes-Stream function, which satisfies the boundary conditions on the symmetry axis, the ground, conical-core surface, and in the far fields. The constant-core solution is recovered in α→0 limit. The cone slope generates qualitatively new kinematics, a radial-velocity cone-correction term, an outwardly migrating updraft annulus over a central downdraft, counter-rotating inner-cell, teardrop-shaped inflow-outflow transition surface z∗(r) that deforms into a curved, non-monotonic boundary. The model is kinematic in nature, and it therefore describes the structure of the vortex, not the dynamical factors, and provides a kinematically consistent description of dust-devil structure and have direct implications for refining dust-flux estimates and radiative-transfer inputs on Earth and Mars and for Martian background, dust opacity between global storms and for arid-terrestrial particulate budgets.
