Space instrumentation

Abstract:

The Europa Thermal Emission Imaging System (E-THEMIS) on the Europa Clipper spacecraft will investigate the temperature and physical properties of Europa using thermal infrared images in three wavelength bands at 7-14 µm, 14-28 µm and 28-70 μm [Christensen et al., 2024]. The specific objectives of the investigation are to 1) understand the formation of surface features, including sites of recent or current activity, in order to understand regional and global processes and evolution and 2) to identify safe sites for future landed missions. The E-THEMIS radiometric calibration includes removing the thermal emission from the instrument housing, optical elements, and filters using observations of space and an internal calibration flag [Christensen et al., 2024]. On February 28, 2025, the Clipper spacecraft performed a close flyby of Mars for a trajectory gravity assist. Twenty four hours prior to closest approach the spacecraft pointed the E-THEMIS instrument at Mars and performed a sequence that scanned E-THEMIS across the planet at a slew rate of 100 micro-radians per second. This rate is the same as what be used to image Europa during each flyby [Pappalardo et al., 2024]. This activity accomplished two primary objectives: 1) collect images of a well-characterized target (Mars) to validate the E-THEMIS calibration methodology and software prior to the first observations of Europa; and 2) rehearse the data collection procedure that will be used to obtain global observations of Europa.Mars makes an excellent thermal calibration target because it has been extensively studied and characterized by numerous thermal infrared instruments. The E-THEMIS observations were simulated using modeled surface temperatures generated using global maps of thermal inertia albedo made from the MGS TES data [Christensen et al., 2001], together with the krc thermal model [Kieffer, 2013]. The wavelength-dependent atmospheric absorption and emission was modeled using data from the UAE Emirates Mars Mission EMIRS thermal infrared spectrometer [Amiri et al., 2022; Edwards et al., 2021]. EMIRS collects global scans of hyperspectral data from 6-100 µm at 5 and 10 cm-1 spectral sampling at ~200 km spatial resolution [Edwards et al., 2021]. These spectra were resampled from wavenumber to wavelength and weighted by the three E-THEMIS spectral bandpasses to produce 3-band simulated E-THEMIS global images. EMIRS data were not collected simultaneously with the E-THEMIS imaging, but global observations were acquired at the same season and within 5° of latitude, 10° of longitude, and 0.3 H local time of the E-THEMIS data. Fig. 1 shows an example of the nearest EMIRS observation to the E-THEMIS observing conditions of sub-spacecraft latitude=20.3° N, longitude=163.0° E, local time=11.48 H, and Ls=50.5°. A transfer function from the krc-generated surface temperatures and the bandpass-weighted EMIRS data was created by averaging the ratio of forty-five EMIRS observations to the krc-generated surface temperatures. Simulated E-THEMIS observations were produced using the average of these ratios and the krc surface temperatures. The results are given in Fig. 2. The E-THEMIS data could not be transmitted to Earth until Clipper was more than 2 AU from Sun due to spacecraft thermal constraints. As a result the data were received on Earth on May 7, 2025, and the results and an assessment of the E-THEMIS calibration will be discussed.Fig. 1. Measured Mars temperatures. Comparison of temperature globes for surface temperature (krc model) and E-THEMIS-bandpass-weighted EMIRS data for Bands 1, 2, and 3. The EMIRS observations were acquired on Feb. 17, 2025, at a sub-spacecraft viewing geometry of 16.0° N latitude, 174.1° E longitude, 11.60 H local time, and 45.5° Ls. Fig. 2. Simulated E-THEMIS temperature images. The data for each E-THEMIS band were created using the krc model surface temperatures transferred to E-THEMIS wavelength bands using a transfer function derived from EMIRS observations. ReferencesAmiri, H., D. Brain, O. Sharaf, P. Withnell, M. McGrath, M. Alloghani, M. Al Awadhi, S. Al Dhafri, O. Al Hamadi, and H. Al Matroushi (2022), The emirates Mars mission, Space Science Reviews, 218(1), 4.Christensen, P. R., et al. (2001), The Mars Global Surveyor Thermal Emission Spectrometer experiment: Investigation description and surface science results, J. Geophys. Res., 106, 23,823-823,871.Christensen, P. R., J. R. Spencer, G. L. Mehall, M. Patel, S. Anwar, M. Brick, H. Bowles, Z. Farkas, T. Fisher, and D. Gjellum (2024), The Europa Thermal Emission Imaging System (E-THEMIS) Investigation for the Europa Clipper Mission, Space Science Reviews, 220(4), 1-65.Edwards, C. S., P. R. Christensen, G. L. Mehall, S. Anwar, E. A. Tunaiji, K. Badri, H. Bowles, S. Chase, Z. Farkas, and T. Fisher (2021), The Emirates Mars Mission (EMM) Emirates Mars InfraRed Spectrometer (EMIRS) Instrument, Space science reviews, 217, 1-50.Kieffer, H. H. (2013), Thermal model for analysis of Mars infrared mapping, J. Geophys. Res, 116, 451-470.Pappalardo, R. T., B. J. Buratti, H. Korth, D. A. Senske, D. L. Blaney, D. D. Blankenship, J. L. Burch, P. R. Christensen, S. Kempf, and M. G. Kivelson (2024), Science Overview of the Europa Clipper Mission, Space Science Reviews, 220(4), 1-58.

Abstract:

Enceladus maintains its global, unconsolidated ocean around its rocky, porous core by tidal dissipation with Saturn and torque from its resonance with Dione [1].  The active South Polar Terrain (SPT) region is associated with intense concentrations of endogenic heat, but it is the significantly lower-power conductive heat flow that dominates global heat loss as it occurs over the entire surface.  If Enceladus’ global ocean is to be sustained over a significant fraction of its existence, heating rates would have to be balanced endogenic heat loss. Estimates of heating rates from models vary from 1.5-150 GW [2].  The large range results from uncertainty in both the structure of the bodies’ interiors and their evolution.  Ice shell thickness/shape models, which interpret gravity, libration and topographic data, produce global conductive heat loss estimates of around 18-35 GW [3,4,5].Endogenic heat loss from the SPT has been estimated using thermal observations from Cassini Composite Infrared Spectrometer (CIRS) to be between 5-19 GW [6,7,8], resulting in a conventional, combined heat loss estimate of around 50 GW [9].Detecting endogenic heat loss using thermal observations presents a significant challenge, principally relating to limited data coverage and uncertainty about the surface thermal properties but is possible under some circumstances [10].We use thermal observations CIRS to identify endogenic heat at the north pole of Enceladus in the form of conductive heat flow.   From this estimate we can infer global average heat loss.  We are then able to invoke the same mechanisms used to estimate the global average heat loss from ice shell thickness models [5, 9] to characterize the first north polar and global average ice shell thicknesses independently derived from thermal observations.Acknowledgments: This work was made possible through NASA’s support of Cassini Data Analysis Program Grant Number 80NSSC20K0477. References[1] Nimmo, F., Barr, A.C., Behounková, M. and McKinnon, W.B., 2018. The thermal and orbital evolution of Enceladus: observational constraints and models. Enceladus and the icy moons of Saturn, 475, pp.79-94.[2] Lainey, V., Casajus, L.G., Fuller, J., Zannoni, M., Tortora, P., Cooper, N., Murray, C., Modenini, D., Park, R.S., Robert, V. and Zhang, Q., 2020. Resonance locking in giant planets indicated by the rapid orbital expansion of Titan. Nature Astronomy, 4(11), pp.1053-1058.[3] Thomas, P.C., Tajeddine, R., Tiscareno, M.S., Burns, J.A., Joseph, J., Loredo, T.J., Helfenstein, P. and Porco, C., 2016. Enceladus’s measured physical libration requires a global subsurface ocean. Icarus, 264, pp.37-47.[4] Čadek, O., Tobie, G., Van Hoolst, T., Massé, M., Choblet, G., Lefèvre, A., Mitri, G., Baland, R.M., Běhounková, M., Bourgeois, O. and Trinh, A., 2016. Enceladus's internal ocean and ice shell constrained from Cassini gravity, shape, and libration data. Geophysical Research Letters, 43(11), pp.5653-5660.[5] Hemingway, D.J. and Mittal, T., 2019. Enceladus's ice shell structure as a window on internal heat production. Icarus, 332, pp.111-131.[6] Spencer, J.R., Pearl, J.C., Segura, M., Flasar, F.M., Mamoutkine, A., Romani, P., Buratti, B.J., Hendrix, A.R., Spilker, L.J. and Lopes, R.M.C., 2006. Cassini encounters Enceladus: Background and the discovery of a south polar hot spot. science, 311(5766), pp.1401-1405.[7] Howett, C.J.A., Spencer, J.R., Pearl, J. and Segura, M., 2011. High heat flow from Enceladus' south polar region measured using 10–600 cm− 1 Cassini/CIRS data. Journal of Geophysical Research: Planets, 116(E3).[8] Spencer, J.R., Nimmo, F., Ingersoll, A.P., Hurford, T.A., Kite, E.S., Rhoden, A.R., Schmidt, J. and Howett, C.J., 2018. Plume origins and plumbing: from ocean to surface. Enceladus and the icy moons of Saturn, 163.[9] Nimmo, F., Neveu, M. and Howett, C., 2023. Origin and evolution of Enceladus’s tidal dissipation. Space Science Reviews, 219(7), p.57[10] Miles, G., Howett., C., Spencer J., Vol. 16, EPSC2022-1190, 2022, https://doi.org/10.5194/epsc2022-119

Abstract:

Introduction: The origins of Mars' moons, Phobos and Deimos, remain uncertain, with two main hypotheses under consideration: formation from debris following a high-energy impact between Mars and an asteroid [1], or capture of primitive asteroids [2]. To address this, JAXA's Martian Moons eXploration (MMX) mission aims to return samples from Phobos by 2031 [3]. The characterisation of these samples will determine the origin of Phobos.To ground-truth remote observations of Phobos, we have used X-ray diffraction (XRD), and Fourier transform infrared (FTIR) reflectance spectroscopy to characterise the bulk mineralogy and IR spectral properties of ureilites, carbonaceous and ordinary chondrites, the composition of which could be indicative of a captured asteroid [4], and Martian meteorites that could represent a collisional formation. By acquiring XRD and IR data from the same material, mineral abundances can be directly correlated with features in reflectance spectra [5]. When MMX reaches Phobos, meteorite data collected in the laboratory will play a crucial role towards interpreting the mineralogy and composition of materials on its surface.Methods: We have characterised the mineralogy and spectral properties of six CM (Mighei-like) carbonaceous chondrites, Tarda (C2-ung), the CO (Ornans-like) chondrite Kainsaz, a range of shock darkened ordinary chondrites (mostly falls) including L4-6, and H5-6, four CR2 chondrites, four ureilites, Martian meteorites Nakhla and Tissint, and a Tagish Lake (C2-ung) based simulant created by the University of Tokyo, known as UTPS-TB [6]. For the meteorites, chips of approximately 200 mg were ground to produce powders with grain sizes of less than 40 microns. The UTPS-TB sample came in a powdered form which was ground to the same grain size as the meteorites.Diffuse reflectance spectra (1.7 - 50 μm) were collected using a Bruker VERTEX 70V FTIR spectrometer at the University of Oxford Planetary Spectroscopy Facility. Spectra were calibrated at the start of each measurement day and between measurements of samples using a gold standard. The powdered sample was measured under a vacuum to reduce terrestrial atmospheric contributions.XRD patterns of the same powders were collected using an INEL X-ray diffractometer with a position-sensitive detector at the Natural History Museum, London. Around 50 mg of powdered sample was measured for 16 hours to achieve good signal-to-noise. Measurements of well-characterised standard minerals were collected for 30 minutes and compared with meteorite patterns to identify minerals and quantify their abundance in the sample [e.g. 7].Results & Discussion: The mineralogical and spectral characteristics of meteorites in this investigation are compared the reflectance spectra of Phobos’ surface. The CR chondrites are primitive, containing both anhydrous silicates (e.g. olivine and pyroxene) and aqueous alteration phases such as phyllosilicates, carbonates, magnetite, and sulfides. Their albedo is ~3-5% reflectance with a weak red slope in the visible to near-infrared (VNIR). The CRs have a 3 μm hydration band, due to partial aqueous alteration. Their low VNIR reflectance, red-sloped continuum, and weak 3 μm spectral absorption feature is like that of Phobos, supporting the captured asteroid origin theory. The CM chondrites share similar spectral features but have a lower albedo and a stronger μm hydration band, corresponding to a higher phyllosilicate composition.   The ureilites are achondritic ultramafic meteorites containing olivine, pyroxene and carbon phases. These samples have a low albedo (~6-15% in VNIR) due to their opaque carbonaceous composition. However, their VNIR spectra are blue-sloped, inconsistent with Phobos’ red-sloped spectra. Ureilites are also anhydrous and therefore lack the 3 μm hydration band seen in Phobos spectra. Their low reflectance and feature-poor spectra could resemble Phobos, however there is a significant difference in spectral slope and hydration features. Therefore, Phobos were composed of ureilitic material, its surface would need to be significantly modified by space weathering.Martian meteorites Nakhla (a nakhlite) and Tissint (a shergottite) have mineralogical and spectral features consistent with their basaltic origin. XRD measurements of these meteorites are dominated by pyroxene (augite, pigeonite), and olivine, consistent with their origin in the Martian crust. Their reflectance spectra have relatively high albedo, mafic absorption bands at ~1 and 2 μm, and a lack of hydration features. These features are inconsistent with the spectra of Phobos, which lack 1 or 2 μm bands and show significantly lower reflectance.CR and CM chondrites are the closest spectral match to Phobos from the samples studied. Their low albedo, red-sloped, hydrated spectra are consistent with surface measurements of Phobos. Ureilites share low reflectance but differ significantly in slope and hydration, while Martian meteorites differ in more spectral characteristics. These results support the interpretation that Phobos is composed of primitive, carbon-rich material, likely of outer solar system origin, and favour a capture scenario over a collisional formation from Martian ejecta. The similarities between the carbonaceous chondrites and Phobos indicates that the Martian moons may be captured asteroids and further demonstrates the importance of the MMX mission sample return for solving the mystery of their origin definitively.References: [1] R. Citron et al. (2015) Icarus 252:334-338. [2] M. Pajola et al. (2013) The Astrophysical Journal 777:127. [3] K. Kuramoto et al. (2022) Earth, Planets and Space 74:12. [4] K. D. Pang et al. (1978) Science 199(4324):64-66. [5] H. C. Bates et al. (2023) Meteoritics & Planetary Science 1-23. [6] H. Miyamoto et al. (2021) Earth, Planets and Space 73:1-17 [7] G. Cressey et al. (1996) Powder Diffraction 11:35-39.

Abstract:

Introduction: The Lunar Thermal Mapper (LTM) is a multispectral infrared radiometer, built by the Oxford Physics Instrumentation Group for the Lunar Trailblazer mission; a small satellite launched in February 2025 under NASA’s Small Innovative Missions for Planetary Exploration (SIMPLEx). Trailblazer aims to advance our understanding of the lunar water cycle by mapping surface temperature, water abundance, distribution and form (OH, H2O, ice) and silicate lithology (i.e., Si-O Christiansen spectral feature). LTM was developed to improve upon existing infrared instrumentation in lunar orbit (e.g., Diviner Lunar Radiometer Experiment, hereafter referred to as Diviner) to provide higher resolution temperature estimations and refine interpretations of thermophysical properties at the surface [2, 3]. Accurately determining surface temperatures on airless bodies is essential for deriving emissivity spectral features (such as the Christiansen Feature and Restrahlen bands, which are diagnostic of silicate lithologies) that are representative of the surface. Temperature errors can affect spectral shape, resulting in the misidentification of surface composition [5, 8].  Our team compared six methods for estimating LTM’s brightness temperature (BT), including the temperature retrieval approach used by Diviner, to (1) determine which method provides the most representative surface temperature and (2) assess how variations in BT estimation affect derived emissivity spectral shape. Despite challenges facing the Trailblazer mission, refining methods for BT estimation remains relevant to the planetary community, as future missions continue to depend on infrared instrumentation and accurate BT retrievals for remote compositional interpretation (e.g., LEAP, L-CIRiS, Europa Clipper).   Instrumentation: LTM is a 15-channel infrared imager that covers a range between 6 to 100 µm [2,3]. LTM advances infrared compositional analysis by incorporating eleven narrowband compositional filters across the 6.25 to 10 µm range. This expanded spectral coverage enables more precise characterization of key features, such as the Christiansen Feature, Reststrahlen bands, and transparency features, which are essential for identifying spectral endmembers (Table 1) [2,3].   LTM builds upon Diviner, a nine-channel instrument that has a broad spectral range from 0.3 to 400 µm (Table 1) [1]. Diviner’s three narrowband compositional channels, 7.55–8.05 µm (Channel 3), 8.10–8.40 µm (Channel 4), and 8.38–8.60 µm (Channel 5), are specifically tuned to capture the Christiansen Feature (CF), an emissivity peak that is diagnostic of broad silicate mineralogy and sensitive to variations in silica content [1,4].  Table 1: LTM and Diviner observational parameters.    Methodology: To assess BT and emissivity retrieval techniques for LTM, we measured four lunar analog samples under controlled laboratory conditions to retrieve high-resolution emission spectra. These laboratory spectra were down-sampled to match LTM’s narrowband spectral resolution. Six BT estimation methods were tested to determine how effectively each method preserved laboratory spectral shape and temperature. The following section describes the laboratory setup and the BT estimation methods examined in this study. Laboratory: Using the PASCALE (Planetary Analogue Surface Chamber for Asteroids and Lunar Environments) in conjunction with a Bruker 70V Fourier Transform Infrared (FTIR) spectrometer, we conducted thermal infrared measurements of four volcanic lunar analogue samples; dunite (Twin Sisters -1 and -2), basalt (BIR-1) and rhyolite (RGM-1) under controlled ambient conditions (350 K, 1000 mbar, N2 atmosphere) [4]. The integration of PASCALE with FTIR allows for the acquisition of thermal emission spectra (as opposed to typical laboratory reflectance), offering a more representative analog of data collected by orbiting infrared instrumentation. Spectra were measured across ~6000 to 350 cm⁻¹ at a resolution of 4 cm⁻¹. Quality assurance and calibration procedures followed established protocols outlined in [6,7,8].  BT Estimations: To evaluate BT performance at LTM’s spectral resolution, each sample’s measured radiance was convolved with LTM’s filter response to simulate instrument-resolution radiance. The resulting spectra were converted to BT using the Planck function. Seven distinct methods were applied to the LTM-resolution BT data to determine the maximum BT values for each sample (Table 2). Emissivity was subsequently derived as the ratio between the observed LTM-resolution radiance and an ideal blackbody at the retrieved maximum BT for each method across all samples. The accuracy of the BT estimation methods was assessed by comparing the resulting emissivity spectra and maximum BT values to the full laboratory reference data (350K and full resolution emissivity). Additionally, a focused comparison with Diviner’s BT retrieval method was conducted to identify method-specific discrepancies and evaluate cross-instrument consistency.Table 2: BT estimation methods Results & Discussion: Six BT estimation methods were applied to laboratory emissivity spectra of four lunar analogue samples (dunite, basalt, and rhyolite), as shown in Figure 2. The associated standard errors (SE) for each method are reported in Table 3. Among the tested approaches, four methods (3rd degree polynomial, quadratic, spline and narrowband maximum) showed close agreement with high-resolution laboratory spectra (Figure 2). Temperature variations across compositions were minor, with low SE values (Table 3).  Since the spline fit did not significantly outperform the simpler polynomial or narrowband methods, lower complexity approaches are preferred for LTM temperature retrievals, with a maximum SE of 3.42%.In contrast, due to limited spectral sampling, the Diviner method underestimates surface temperatures by up to 19 K (SE max: 5.55%) in the dunite (TS-2) sample. Expanding this analysis to include a broader range of lithologies or impacted processed samples would help assess whether the Diviner approach (and potential other methods with sparse spectral sampling) introduce systematic shifts in the Christiansen Feature (CF) position or affect the spectral shape relative to more spectrally resolved techniques.  Table 3: BT estimations and associated SE of temperature for dunite (TS-1, TS-2), basalt (BIR-1) and rhyolite (RGM-1). Fig 2: Six BT methods are fitted to laboratory emissivity spectra of four lunar analogues. Conclusion:Comparisons between BT estimation methods indicate the 3rd-degree polynomial, quadratic, and narrowband maximum methods offer the best agreement with laboratory data (SE max: 3.42%). Although Diviner’s method tends to underestimate surface temperatures (up to 19 K), it still preserves spectral shape and wavelength range, supporting the reliability of compositional interpretations. Expanding the dataset to include a broader range of compositions could confirm whether different approaches result in systematic shifts in the Christiansen Feature across different lithologies. This work enhances the accuracy of remote compositional interpretation and supports future exploration on airless bodies.

Abstract:

In this presentation, we will show efforts made to include accurate photochemical modelling of hydrogen chloride (HCl) and ozone (O3) in the Mars Planetary Climate Model in order to reconcile recent observations.The ExoMars Trace Gas Orbiter (TGO) has detected and characterised trace gases in the Martian atmosphere over several Mars years. With its data, upper limits of potential constituents have been constrained, the accuracy of species’ concentration measurements has been improved, and seasonal and spatial variations in the atmosphere have been observed. The wealth of data obtained has addressed several open questions about the nature of Mars’ atmosphere, while other measurements have revealed much that remains poorly understood. For example, models continue to struggle to reproduce ozone distributions, both spatially and temporally, as well as seasonal variations in atmospheric oxygen (O2), suggesting that some key photochemical interactions may be being overlooked. As another example, despite seven years of dedicated observations producing very low upper limits on atmospheric methane levels, there remains no unifying hypothesis that simultaneously explains the detections reported by other Mars assets at Gale Crater [e.g., 1-4].Hydrogen chloride—the first new gas detected by TGO [5,6]—has been investigated recently using the mid-infrared channel on TGO’s Atmospheric Chemistry Suite (ACS MIR) [7,8]. Observations show a strong seasonal dependence of HCl in the atmosphere, with almost all detections occurring during the latter half of the year between the start of dust activity and the southern hemisphere autumnal equinox. There are also unusual measurements of HCl, localised in both time and space, during the aphelion season. Chlorine-bearing species such as HCl are important to understand in the Mars atmosphere because on Earth they are involved in numerous processes throughout the planetary system, including volcanism, from which HCl on Earth ultimately originates. Further, chlorine species play a key role in atmospheric chemistry: they influence oxidative chemistry and variations in the aforementioned O2 and O3 concentrations (e.g., by catalysing the destruction of ozone), and by extension, potential CH4 in the Martian atmosphere [9]. However, much remains unknown about original source and sinks of HCl, as well as the factors controlling its distribution and variation.Here, we use the Mars Planetary Climate Model—a 3-D global climate model that includes a photochemical network—to investigate potential mechanisms accounting for patterns in ozone and HCl detections and interactions between them. We begin with the role of heterogeneous chemistry involving ice and dust aerosols, by implementing modelling developed for the Open University Mars Global Climate Model [10] and building on existing chlorine photochemical model networks [11,12,13]. Heterogeneous chemistry affects the abundances of oxidative species such as OH and HO2, and by extension, O and O3. In addition, we investigate how such processes can potentially serve as a mechanism for direct release and sequestration of HCl from the atmosphere. We also explore potential mechanisms behind the annual occurrence of spatially-constrained aphelion HCl, including volcanic sources, and we investigate the interplay between chlorine-bearing species and OH, HO2,O, and O3. Figure 1 shows the way that HCl appears during spring and summer in the southern hemisphere (solar longitudes 180-360°) when water vapour is present in the Martian atmosphere. Ozone behaves in the opposite manner and is present when water vapour abundances are low. As shown, these species are anti-correlated; we explore the important chemical pathways connecting them.Understanding the role of oxidative chemistry on HCl and other trace gases is key to achieving a more complete picture of processes occurring in the present-day Mars atmosphere, as well as processes that have shaped its evolution and habitability.Figure 1: Observations of CO, O2, O3 and HCl seasonally and across multiple Mars Years. Upper panel: CO and O2 observations from Curiosity’s Sample Analysis at Mars (SAM) instrument (stars; [14]) and the Mars Climate Database (lines; [15]). Lower panel: O3 and HCl observations from TGO’s ACS instrument [8]. MY=Mars Year; NH/SH=northern/southern hemisphere. Figure from Kevin Olsen.References:[1] Giuranna, M., et al. (2019). Nat. Geosci. 12, 326–332. [2] Korablev, O. et al. (2019). Nature 568, 517–520. [3] Montmessin, F. et al. (2021). Astron. Astrophys. 650, A140. [4] Webster, C. R. et al. (2015). Science 347, 415-417. [5] Korablev O. I. et al. (2021). Sci. Adv., 7, eabe4386. [6] Olsen K. S. et al. (2021). Astron. Astrophys., 647, A161. [7] Olsen K. S. et al. (2024a). JGR, 129, e2024JE008350. [8] Olsen K. S. et al. (2024b). JGR, 129, e2024JE008351. [9] Taysum, B. M. et al. (2024). Astron. Astrophys., 687, A191. [10] Brown M. A. J. et al. (2022). JGR, 127, e2022JE007346. [11] Rajendran, K. et al. (2025). JGR: Planets 130(3), p.e2024JE008537. [12] Streeter, P. M. et al. (2025). GRL 52(6), p.e2024GL111059. [13] Benne, B. et al. (2024). EPSC, pEPSC2024-1037. [14] Trainer, M. G. et al. (2019). JGR 124, 3000. [15] Millour, E. et al. (2022). Mars Atmosphere: Modelling and Observations, p. 1103.