The Interstellar Dust Experiment (IDEX) is a dust impact ionization Time-of-Flight (ToF) mass spectrometer launched onboard the Interstellar Mapping and Acceleration Probe (IMAP) on September 24, 2025. IMAP is in nominal science operations at the Sun-Earth Lagrange Point L1, with IDEX passively collecting cosmic dust grains at a cadence of roughly one interplanetary particle per week. IDEX will detect and analyze both Interstellar Dust Grains (ISDs) from the Local Interstellar Medium (LISM) as well as Interplanetary Dust grains (IDPs). ISD collection will begin in April 2026 as we enter the interstellar dust focusing season. IDEX will collect a variety of ISDs and IDPs over its lifetime, ranging from pristine to heavily processed particles that are a mixture of mineral and organic material.We investigate how IDEX can be used to determine the degree of processing dust grains have undergone. These studies inform the analysis of IDEX flight data representative of organic and mineralogical cosmic dust grains. Assessments of aromaticity and the presence of functional groups can be used to determine the processing of organic species. Polycyclic aromatic hydrocarbons (PAHs) are the most pristine organic compounds. PAH destruction and processing lead to the production of heterocyclic compounds and decreasing aromaticity in organic species. Minerals can be appraised via the degree of serpentinization and conversion from crystalline to amorphous silicates. IDEX's large effective area combined with high mass resolution (m/dm > 200) and dynamic range make it well suited to assess minute variations in mass spectra pointing to pristine versus processed materials. Various campaigns from the last two years build and support the techniques presented here to analyze IDEX flight data.

The icy ocean moons Enceladus and Europa offer potentially habitable environments below their icy crusts. Ice grains ejected from cryovolcanic plumes [1,2] and micrometeorite bombardment can be sampled by impact ionization mass spectrometers, as performed in the past by the Cosmic Dust Analyzer (CDA; [3]) onboard Cassini in the Saturnian system. Successor instruments to the CDA include the SUrface Dust Analyzer (SUDA; [4]) onboard NASA’s Europa Clipper mission and the HiFi instrument for a future Enceladus mission [5]. The strongly enhanced capabilities of SUDA and contemporary instruments, relative to CDA, allow the identification of molecular biosignatures. Among possible molecular biosignatures, amino acids are essential building blocks of proteins and play a crucial role in the formation of water-based life as we know it, thus their identification on extraterrestrial water worlds is key to the search for life beyond Earth.Laboratory analogue experiments using laser-induced liquid beam ion desorption (LILBID [6]) have demonstrated that impact ionization mass spectrometers can detect amino acids [7] down to the ppm or ppb level, if they are entrapped in emitted ice grains, and can distinguish between abundance patterns of abiotic and biotic formation processes [8]. However, at any given molecular mass of an amino acid, several isomers (identical molecular formula but distinct arrangements of atoms in space) exist, which are indistinguishable by their molecular peaks in recorded mass spectra. Until now, it was unclear whether isomeric amino acids can be discriminated from each other, e.g., by fragmentation patterns in impact ionization mass spectra.Here, using LILBID mass spectrometry, we conducted a cation mode analysis of eight isomeric amino acids with an identical molecular mass of 131.173 u and formula C6H13NO2 [9]. The recorded mass spectra were investigated for spectral features that enable differentiation of the different isomeric amino acids, with the aid of quantum chemistry calculations.We show that the amino acid isomers (including diastereoisomers) can be uniquely identified due to their distinct mass spectral features and fragmentation patterns. Several observed fragments and their intensities can be explained through intramolecular hydrogen bonding and other structural effects originating from the parent molecules. Importantly, α-amino acids can be clearly differentiated from non-α-amino acids, because they have lower proton affinities than non-α-amino acids, which result in lower ionization efficiencies for α-amino acids. Additionally, we further complement the LILBID database [10], which already contains a large variety of analogue mass spectra of both organic and inorganic compounds, for upcoming missions to icy ocean moons.The ability to discriminate amino acid isomers in a robust and reliable manner highlights a novel ability of impact ionization mass spectrometers that has significant implications for the search of biosignatures in the solar system, in particular for SUDA on Europa Clipper and other future instruments onboard missions exploring ocean worlds.[1] F. Spahn et al., Science, 311, 1416-1418 (2006)[2] L. Roth et al., Science, 343, 171-174 (2014)[3] R. Srama et al., Space Sci. Rev., 114, 465-518 (2004)[4] S. Kempf et al., Space Sci. Rev. 221, 10 (2025)[5] O. Mousis et al., The Planetary Science Journal, 3(12), 268 (2022)[6] F. Klenner et al., Rapid Commun. Mass Spectrom., 33, 1751-1760 (2019)[7] F. Klenner et al., Astrobiology, 20, 179-189 (2020)[8] F. Klenner et al., Astrobiology, 20, 1168-1184 (2020)[9] J. Bönigk, et al. Astrobiology 15311074261443835 (2025)[10] F. Klenner et al., Earth Space Sci., 9, e2022EA002313 (2022)

Dust in the atmosphere of Mars, along with its radiative effects, is the central factor for understanding the Martian climate. Global circulation models and remote sensing observations are used to shed light on the evolution of Martian dust storms. Trajectories of Martian dust storms have been investigated by manual treatment of Mars daily global maps from the MARs Color Imager. However, the tracking of dust storms has neither been automated, nor systematically compared with modeled dust storm trajectories. We therefore developed a simple algorithm to detect regions with an enhanced atmospheric dust content and to attribute these regions to a trajectory. We applied this algorithm to daily global maps of measurements of the column dust optical depth for Mars Years 24-35, and found 20 dust storm trajectories lasting for at least 10 Sols. We compared these observation-based trajectories with the corresponding model-based trajectories from our own simulations using the global circulation model Mars Planetary Climate Model version 6. The obtained distributions of storm speed and direction of propagation show strong similarities between observations and model, demonstrating a reasonably good performance of the model with regard to dust storm trajectories. We find that most dust storms on Mars are traveling east- or westwards, but that dust storms propagating westwards are less well represented in the model. The developed algorithm can be used as a tool for model evaluation, but also for tracking meteorological conditions along dust storms' trajectories, allowing for further development of dust storm understanding.

Impact ionization mass spectrometers, such as Cassini's Cosmic Dust Analyzer, are capable of detecting macromolecular organic compounds in ice grains ejected from icy moons such as Enceladus and Europa. The identification of their chemical features relies on laboratory analogue experiments that replicate ice grain impact ionization mass spectra, such as the laser-induced liquid beam ion desorption (LILBID) technique. Both space-borne instruments and analogue experiments require a deeper understanding of measurement-associated processes affecting mass spectral features, and in particular protonation-induced chemical transformations (PICTs). Here, we investigate the molecule amygdalin (C20H27NO11) as a model high-mass, complex organic compound using LILBID to determine its mass spectral fingerprint. Our results show that amygdalin undergoes unexpected PICTs enabled by the high laser energy input upon measurement. The chemical transformations are promoted by the proton-rich environment created upon the disintegration of the water matrix. This reactivity is distinct from other well-characterized phenomena affecting analytes under LILBID conditions (e.g., fragmentation). Protonation triggers reactivity in amygdalin's nitrile group resulting in multiple products that appear as characteristic molecular ions. Nuclear magnetic resonance spectroscopy experiments confirm that this reactivity occurs under LILBID measurement, not in solution prior to desorption. Compounds with similar functional groups (e.g., amide or ketone) could, in principle, also be subject to PICTs. PICTs could also occur in space during space-borne impact ionization, potentially complicating the identification of analytes embedded in ice grains. Our work builds toward a better understanding of the effects of PICTs in the detection of organic compounds with impact ionization mass spectrometry.

Enceladus and Europa are compelling targets for astrobiology investigations due to their potentially habitable subsurface oceans connected to the icy surface by geological processes. Both moons emit ice grains either ejected via micrometeoroid surface impacts or erupted from their interiors through plume activity. These grains can be sampled by spacecraft flybys, and their composition can be analyzed by impact ionization mass spectrometers, such as the SUrface Dust Analyzer (SUDA) onboard Europa Clipper, or similar instruments proposed for future Enceladus missions. These instruments can identify potential biomolecules, such as amino acids, down to nanomolar concentrations, as demonstrated through previous laboratory experiments. However, the identical masses of isomeric compounds could hinder the mass spectrometric identification and assignment of molecular biosignatures. Here, we investigate the general capability of impact ionization mass spectrometry to distinguish between isomeric compounds, validated with a test case of eight amino acid isomers with an identical molecular mass of 131.173 u and formula C6H13NO2, using quantum chemical calculations. We show that the amino acid isomers (including diastereoisomers) can be uniquely identified due to their distinct mass spectral features and fragmentation patterns, explained through intramolecular hydrogen bonding and other structural specificities of the individual isomers. Importantly, α-amino acids can be clearly differentiated from non-α-amino acids owing to several major mass spectral features. We show that SUDA-type instruments have sufficient capabilities to differentiate certain isomers and to identify biosignatures from ocean worlds with high confidence.

Organic compounds are a ubiquitous component of cosmic dust and provide insight into the origin of planetary systems, the availability of carbon for life in the solar system and beyond, and the distribution of potential biosignatures in the universe. Compositional and dynamical analysis of such dust grains can shed insight into their origin. The Destiny Dust Analyzer (DDA) onboard JAXA’s interplanetary space mission DESTINY+ will detect and analyse the composition of (sub-)micron sized dust ejecta during flybys of asteroids Apophis and Phaethon [1,2]. DDA will characterise both interplanetary and interstellar dust grains during the mission’s lifetime [3]. DDA is an impact ionisation time-of-flight mass spectrometer, whereby dust particles incident onto the instrument’s target at hypervelocity (≥ 2 km s-1) vaporise and partially fragment into various constituent ions and neutrals. Here, we investigate the capability of DDA to detect a mixture of complex organic compounds in single cosmic dust particles. An organic cosmic dust analogue is prepared by coating polycyclic aromatic hydrocarbon, perylene (C20H12), microparticles with an ultrathin overlayer of a conductive polymer, polypyrrole H(C4H2NH)nH, to enable acceleration up to hypervelocities with a high-voltage van de Graaff instrument. Time-of-flight mass spectra obtained at impact speeds ~3-20 km/s are recorded in this calibration campaign. The characteristic parent molecular ion for perylene, [C20H12 (+H)]+, is observed at m/z 251 ± 1 in mass spectra arising from impacts between 3 and 8 km s-1. However, between 8 and 18 km s-1, no such parent ion is observed. Instead, impact ionisation mass spectra exhibit a characteristic series of homologous [CnHm]+ fragments originating from both polypyrrole and perylene, alongside some non-sequential ions which may be diagnostic for distinguishing between different organic components in cosmic dust. The contributions of each species to fragmentation patterns in the mass spectra is coupled with the impact velocity. Our results are in agreement with Mikula et al. (2024), who investigated impact ionisation of polypyyrole-coated anthracene particles for the Interstellar Dust EXperiment (IDEX) onboard NASA's Interstellar Mapping and Acceleration Probe (IMAP), and observed a similar relationship between fragmentation pattern and velocity [4].Additional experiments with a range of PAHs, heterocycles, and lower mass organics at various velocities, will yield further insight into the detection and characterisation of heterogeneous dust likely to be encountered by DDA. Similarly, theoretical chemical calculations could assist in deciphering the contribution of different species to mass spectral features via the analysis of dissociation thermodynamics and kinetics.[1] Ozaki et al. (2022) https://doi.org/10.1016/j.actaastro.2022.03.029[2] Simolka et al. (2024) https://doi.org/10.1098/rsta.2023.0199[3] Krüger et al. (2024) https://doi.org/10.1016/j.pss.2024.106010[4] Mikula et al. (2024) https://doi.org/10.1021/acsearthspacechem.3c00353

In-situ observations of Enceladus' plume and Saturn's E ring by the Cassini spacecraft have revealed that some ice particles erupted from Enceladus contain a large inventory of organic materials. These include both high- and low-molecular-weight hydrocarbon chains, aromatic-, nitrogen-, and oxygen-bearing compounds. Here we report experimental results on organic synthesis through hydrothermal (up to 150 degrees C) and freezing (down to -40 degrees C) processes using starting solutions simulating Enceladus' ocean. We find that, owing to HCN and NH3 in the starting solutions, amino acids, together with aldehydes, carboxylic acids, amines, and nitriles, are the primary products of hydrothermal synthesis. Freezing of the starting solutions can also form simple amino acids, such as glycine. Comparing with Cassini's observations, most of our hydrothermal products are in good agreement with observations arguing for a deep plume source, but amino acid-relevant molecular signals in the experiments appear to be absent in Enceladus' organic-rich particles. One possibility for this discrepancy is that partitioning of amino acids into salt-rich plume particles may obscure detection. Macromolecules with aromatic constituents and long hydrocarbon chains in Enceladus cannot be replicated in our experiments. Primordial organic matter or catalytic reactions at elevated temperatures (>150 degrees C) might contribute to the formation of macromolecules in Enceladus.

The first long-distance observations of the Kodiak butte made by the Mars2020 rover "Perseverance" confirmed Gilbert-type delta deposition within a closed-lake system in Jezero crater, Mars. Several outcrops at the actual delta were imaged later during the science campaign but their geology and potential relationship to Kodiak still need to be explored. In this study, we use image data from the Perseverance rover, primarily from the Mastcam-Z and Supercam instruments, to create four digital outcrop models (DOMs) by applying commercial Structure-from-Motion (SfM) photogrammetry software and spatially align the models using SPICE-derived position and orientation data. We analyze the DOMs using the Pro3D software by Joanneum Research, extracting dip and strike as well as size measurements of debris for determining 2D-clast size-frequency distributions. Evidence gathered from the DOMs shows sedimentary facies associated with Gilbert-type delta stratal architectures. Topset, foreset and lower foreset facies were identified at the outcrops Franklin Cliff and Whale Mountain, which additionally displays a prominent mouth bar deposit. Topset-foreset boundaries differ in altitude between outcrops, suggesting different phases of delta progradation and a lake-level rise. Inferred paleo flow directions from Whale Mountain and Franklin Cliff link those to the delta strata found at Kodiak, further indicating that the butte was once part of the delta. Mastcam-Z and Supercam imaged several conglomerates embedded at the delta front, from those six conglomeratic clast samples were taken, prepared and analyzed on image mosaics regarding size-frequency distribution and discharge rates. Three populations of boulder conglomerates can be distinguished, two deltaic (delta slope, delta plain) and one non-deltaic (flood) in origin. The four derived high-resolution, textured and accurately aligned DOMs are made publicly available.

Enceladus is one of the most compelling targets for habitability investigations due to the dynamic interplay between its porous rocky core and the overlying ocean (Waite et al., 2017 ; Choblet et al., 2017). Hydrothermal percolation through the core drives continuous water-rock interaction and facilitates the leaching of biologically relevant elements (Hsu et al., 2015 ; Waite et al., 2017) and potentially insoluble and soluble organic matter (Postberg et al., 2018; Khawaja et al. 2019, 2025). It has recently been demonstrated that complex physicochemical exchanges occur in the ice vents above the water table, where varying freezing of large liquid droplets, differential salt fractionation, and mechanical fragmentation through repeated wall collisions within narrow ice vents can collectively govern the composition and size distribution of the ice grains ultimately ejected into the plume, supported by both experimental laboratory simulations and thermodynamic modelling (Postberg et al. 2026, Science Advances, in review). Evidence suggests that organic-enriched ice grains form primarily through film or bubble bursting at the ocean surface, where a thin layer of refractory, organic material accumulating at the oceanic water table is dispersed by ascending gas bubbles, generating organic-rich droplets alongside salty water aerosols (Postberg et al., 2018). Aqueous mixtures of salts and soluble organic matter exhibit complex behavior upon freezing, including mutual interactions that influence partitioning, yet this phenomenon remains unexplored in the context of Enceladus-relevant systems at the droplet scale. Here we investigate how dissolved organic compounds influence salt partitioning and their own spatial localization within frozen droplets. Our study evaluates these effects under two contrasting freezing regimes (slow vs. flash freezing) and across varying droplet size, revealing also how thermal kinetics and scale dictate the salt-organics structure. To systematically probe the role of molecular structure and functional group chemistry, we selected representatives spanning key organic classes with different moieties: Glycine as an amino acids, Glycerol as a polyol, and 2,3-dihydroxybenzoic acid (DHBA) as an aromatic model, offering a structural parallel to the complex heterocyclic, N-bearing and O-bearing species recently characterized in Enceladus’ ice grains (Khawaja et al., 2025). Spatial correlations between organic matrices and salts were established via a multi-modal imaging approach; high-resolution Raman micro-mapping identified organic domains, whereas subsequent EPMA provided the high-sensitivity elemental distributions required to delineate salt deposition sites.Our results demonstrate that the molecular nature of these organics significantly dictates both salt partitioning and their own spatial localization during freezing. Figure 1 illustrates the behavior of a slow-freezed Glycine-bearing salt matrix. The progressive precipitation of salts concluding with NaCl due to its low eutectic point, induces a marked brine rejection effect, systematically partitioning the amino acids into the diminishing liquid phase. As halite crystals formed, their rigid inorganic lattices rejected the larger organics molecules, leading to a marked cryoconcentration of these compounds within the residual high salinity brine. Consequently, just prior to total solidification at the eutectic point, the organic matter became localized and concentrated at the interfacial margins and grain boundaries of the NaCl crystals since EPMA results also colocalize Na and Cl in these regions. This spatial distribution suggests that the organic fractions mainly remained mobile within the interstitial brine until the final stages of thermal transition, resulting in their eventual entrapment as peripheral inclusions. The same physical phenomenon is also observed with Cysteine amino acid containing analogue droplets in similar sizes, implying this physical positioning can be a common fate for amino acids during freezing. Our results demonstrate that freshly ejected NaCl-rich grains from wall-collisions would preferentially preserve - or even concentrate - amino acids, thereby representing high-priority sampling targets for future in situ missions to Enceladus. Notably, 2,3-DHBA and glycerol exhibited strikingly distinct partitioning patterns under identical conditions, raising intriguing questions about whether molecular structure and functional group chemistry not only govern organic sequestration in icy grain matrices, but also actively shape the salt crystallization environment itself.

Ice grains emitted by the Saturnian moon Enceladus were sampled by Cassini's Cosmic Dust Analyser (CDA) using impact ionization mass spectrometry. CDA revealed that Enceladus hosts a rich organic and inorganic chemical inventory in its subsurface ocean, hinting at its potential habitability. Analysis of fragmentation patterns with laser desorption experiments for the interpretation of CDA data has been essential; however, theoretical insights regarding both fragmentation and ionization processes are often missing. Here, we use density functional theory methods to investigate the energies for dissociation channels of phenol, a model aromatic compound for the features observed by CDA. The fragmentation channels are compared to experimental spectra obtained by using laser-induced liquid beam ion desorption (LILBID) mass spectrometry, an analogue for ice impact mass spectra. Our findings suggest that protonation is the dominant mechanism of ionization, that dissociation from the radical cation and neutral phenol molecule is limited, and that multiple isomers of the protonated molecule act as starting points for dissociation. The highest-intensity organic fragments observed in the LILBID spectrumarising from the losses of CO, [M + H-CO]+, and water, [M + H-H2O]+are found to be both thermodynamically and kinetically accessible. We examined water-molecule interactions during the initial production of the protonated molecule. The presence of water significantly influences the preferred site of protonation and causes variation in the relative energy ordering of the protomers. This work builds toward a computational model of ice grain impact ionization mass spectrometry, relevant for missions such as Europa Clipper and ESA's L4 mission to Enceladus.

One of the challenges in reconstructing the water history of Jezero crater, Mars, is understanding the relationship between the deposition of the western and the northern deltas. Although the western delta appears to be less eroded and younger than the northern delta, multiple scenarios for their deposition have recently been proposed, including simultaneous formation of the northern and western fans/deltas. In our study, we combined topographical and compositional data to determine the origin of the low-calcium pyroxene (LCP) and olivine/carbonate units which were found within the northern and western deltas. We investigated whether these units are representative of the structure of the northern delta, and after analyzing the combined topographic and compositional profiles, no prominent stratigraphic correlations showing parallel layering were found. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data shows that the closest possible source of LCP is the western delta and the watershed of the western inlet. Therefore, we interpret the uppermost LCP unit within the northern delta as material transported from the western inlet which draped the already existing topography of the northern delta. That means that the northern delta (except for several locations between the delta and buttes) was already eroded to the current topography before the deposition of the LCP unit. To test this interpretation, we modeled the distance at which sediments transported from the western inlet through the channel on the western delta would be deposited. The results are consistent with the location of the LCP unit on top of the northern delta. That leads to the conclusion that there was a period when an active western inlet provided sediments which covered parts of the already eroded northern delta. Therefore, the main body of the Jezero's northern delta is older than the western delta but was partly covered with a relatively thin younger layer of material from the western inlet.

One of the central goals of astrobiology is to test the hypothesis that extraterrestrial life exists. In practice, this means seeking imperfect proxies for life, or ‘biosignatures’. Experience shows that ambiguous and contestable results are common in this field. Many astrobiologists are highly attuned to the possibility of ‘false positive’ results that incorrectly indicate the discovery of life. But what if we fail to detect life that is (or was) actually present? Such ‘false negatives’ are bound to arise and they matter because they would represent failures to recognize past or present existence of life. Unlike false positives, false negatives are not currently high on research agendas, as they do not pose immediate risks. Here we identify multiple potential sources of false negatives in the search for life, including factors related to the abundance, activity, appearance and location of life; the preservation and detectability of its observable traces; and the limitations inherent in our detection methods. We call for the development of a deliberate research strategy that systematically addresses these risks. Identifying and constraining such sources is essential to reduce the likelihood of overlooking genuine evidence of life. It is important that astrobiology considers the case of not being able to recognize past or extant presence of life in observations—false negatives. This Perspective identifies sources of false negatives and suggests a framework focused on reducing their risk.

In our study we examined water-related processes and events in the Jezero crater on Mars using flow discharge and sediment transport models of: 1) the western inlet valley carving, 2) the northern inlet valley carving, 3) crater flooding by only northern inlet and 4) by both northern and western inlets, 5) erosion of the western rim by the western inlet, 6) erosion of the eastern rim due to the outlet, 7) water outflow from the crater, 8) outlet valley carving, 9) western delta deposition, 10) northern delta deposition. Detailed geomorphological analyses, delta and valley mapping and measurements served as a base for our investigations. As our knowledge is limited mostly to remote sensing data and only few in situ data from the Perseverance rover, a range of scenarios for each event was modeled by varying, where necessary, the values of input parameters - grain size, channel depth, channel width, channel slope, median grain size, 90th percentile grain size. We calculated the minimum timescales and the minimum volume of available water for each event. The obtained results were interpreted, taking into account the limitations of the model. We found that: 1) the northern inlet participated in the first crater flooding and the eastern rim breaching and it alone could have flooded the crater; 2) the northern and western deltas were deposited during the last incisions of the corresponding inlets; 3) Jezero crater was flooded multiple times, implying open-basin lake conditions during or after the eastern rim breaching. Our findings complement results and interpretations of previous studies and also reveal new insights into the fluvial history in Jezero crater.

The Cosmic Dust Analyzer (CDA) on the Cassini spacecraft has convincingly demonstrated the scientific value of mass spectra of ice particles ejected by the plume on Saturn's ice moon Enceladus. Trace amounts of organic and inorganic molecules embedded in ice particles revealed invaluable insight into the chemical composition of the ocean beneath the moon's icy crust. However, it became quickly obvious that to address open questions about the astrobiological nature of the ocean requires impact ionisation mass spectrometers with a considerably higher mass resolution than that of the CDA instrument of m/Δm ~ 50. Other CDA shortcomings include target cleanliness issues and the low detection cadence of 1 impact per second. The High Ice Flux Instrument (HIFI) is a reflectron-type impact mass spectrometer specifically designed for such applications. It has a mass resolution of 1000 to 2000 and has been optimized for using the electronics of the Surface Dust Analyser instrument on Europa Clipper for recording the spectra. To ensure a high mass resolution HIFI has a long drift region and uses a set of electrostatic Einzel lenses to prevent the ion beam from diverging before entering the single stage reflectron region. The reflectron optics is composed of 23 precision machined electrostatic electrodes to guarantee a smooth reflecting field. In contrast to previous reflectron impact mass spectrometers such as CIDA enter the impacting particles the spectrometer through the reflectron to strike the target at a right angle. The target itself is a highly polished Titanium carrier coated with 250 nm of high purity Iridium (nm surface roughness). The high atomic mass of Iridium ensures that no target lines as well as target cluster lines appear in the mass range ≤ 200 u relevant for the compositional analysis of mineral and ice particles.The instrument performance has been verified through the impact of metal particles at high velocities. Additionally, experiments were conducted with ice particles to illustrate the capacity of HIFI to discern minute quantities of salts and organics in the spectra of water ice.

Over the course of NASA’s Dawn Discovery mission, the onboard framing camera mapped Ceres across a wide wavelength spectrum at varying polar science orbits and altitudes. With increasing resolution, the uniqueness of the 92 km wide, young Occator crater became evident. Its central cryovolcanic dome, Cerealia Tholus, and especially the associated bright carbonate and ammonium chloride deposits—named Cerealia Facula and the thinner, more dispersed Vinalia Faculae—are the surface expressions of a deep brine reservoir beneath Occator. Understandably, this made this crater the target for future sample return mission studies. The planning and preparation for this kind of mission require the characterization of potential landing sites based on the most accurate topography and orthorectified image data. In this work, we demonstrate the capabilities of the freely available and open-source USGS Integrated Software for Imagers and Spectrometers (ISIS 3) and Ames Stereo Pipeline (ASP 2.7) in creating high-quality image data products as well as stereophotogrammetric (SPG) and multi-view shape-from-shading (SfS) digital terrain models (DTMs) of the aforementioned spectroscopically challenging features. The main data products of our work are four new DTMs, including one SPG and one SfS DTM based on High-Altitude Mapping Orbit (HAMO) (CSH/CXJ) and one SPG and one SfS DTM based on Low-Altitude Mapping Orbit (LAMO) (CSL/CXL), along with selected Extended Mission Orbit 7 (XMO7) framing camera (FC) data. The SPG and SfS DTMs were calculated to a GSD of 1 and 0.5 px, corresponding to 136 m (HAMO SPG), 68 m (HAMO SfS), 34 m (LAMO SPG), and 17 m (LAMO SfS). Finally, we show that the SPG and SfS approaches we used yield consistent results even in the presence of high albedo differences and highlight how our new DTMs differ from those previously created and published by the German Aerospace Center (DLR) and the Jet Propulsion Laboratory (JPL).

Patterned ground, especially polygonal surface structures, are of particular importance for planetary sciences, as they are known from the Earth as well as from other celestial bodies such as Mars, Mercury, Venus and Pluto. They are therefore ideally suited as a basis for analogue studies. However, the classification of these structures is often based on individually and intuitively perceived parameters, which are difficult to determine, especially with remote sensing data. In our work, we therefore propose a new classification of polygonal surface structures. Based on a variety of conventional and established geometric parameters, in combination with the innovative approach of fractal geometry, we suggest a classification based on objective mathematical parameters. Based on remote sensing data from more than 100 sites, we show that polygons of different depositional environments can be distinguished and assigned to specific environmental conditions based on purely geometric data. Polygons formed in periglacial depositional environments can be clearly distinguished from structures formed in arid to hyper-arid environments. Furthermore, the structures can be correlated with the known subsurface conditions. The polygon classes resulting from the geometric investigations show a strong correlation with the ground ice content of the depositional areas. Polygons can thus serve as proxies, for example, to identify suitable landing sites for future Mars missions.

The Interstellar Dust Experiment (IDEX) onboard NASA’s Interstellar Mapping and Acceleration Probe (IMAP) is dedicated to measuring the flux, size distribution, and composition of Interstellar (ISD) and Interplanetary (IDP) Dust Particles while stationed at Lagrange point L1 of the Earth-Sun system. IDEX is an impact ionization Time-of-Flight (TOF) mass spectrometer that measures the elemental and/or molecular and selected isotopic composition of impacting dust particles. Due to its high sensitivity and large detection area, IDEX is expected to detect and analyze approximately 200 ISD and 1250 IDP particles over the first two years of the mission.

Astrobiology is a scientific field that is very interdisciplinary and developing very fast, with many new discoveries generating a high level of attention in both the scientific community and the public. A central goal of astrobiology is to discover life beyond Earth which is, with our current instrumentation and knowledge, arguably within our reach. However, knowledge exchange crossing disciplinary boundaries is becoming increasingly challenging due to different usage of nomenclature and scientific controversies often limited to subdisciplines. There have been some efforts to compile organized databases of terms, concepts and other relevant material within some of the subfields contributing to astrobiology, for example through manually curated online portals designed to benefit students, teachers and practitioners of astrobiology-related research. However, the developments within the subfields and the potentially premature communication of research findings are too fast for objective research portals to remain reliable and up-to-date enough to enable well-informed scientific discussions. We suggest here a novel strategy for developing an online tracers portal as a self-maintaining and self-updating information platform, that would allow not only for a relatively unbiased selection of research results, but also provide fast access to latest scientific discoveries together with potential controversies, such that users of the tracers portal can form their own opinion on all available data rather than obtaining an already filtered and potentially biased selection of information.

Jezero crater, which once contained a paleolake, is the investigation site of the current NASA's Mars 2020 mission. We modelled 9 water related processes in Jezero: 1) western inlet valley carving, 2) northern inlet valley carving, 3) crater flooding by only northern inlet and 4) by both northern and western inlets, 5) erosion of the eastern rim for the outlet, 6) water outflow from the crater, 7) outlet valley carving, 8) western delta deposition, 9) northern delta deposition. We claim that the northern inlet had participated in the crater flooding because it has terraces at the same height level as the breaching terraces in the outlet (breaching happened in 3 phases, as shown in [1]).Measurements of channel sizes, valleys, deltas, eroded rim and outflowed water volumes were conducted in ArcGIS 10.8 using Mars 2020 Science Investigation CTX DEM Mosaic and HRSC Mars Chart DTM and corresponding ortho-mosaics.We used flow discharge and sediment transport models by [2] to calculate minimum water and sediment transport timescales under constant bank-full discharge. For northern and western inlet-related processes we took 0.005 m as median grain size D50 (it is the biggest grain size reported for samples from the western delta front in [3] so far; considering that the delta front is characterized by fine-grained deposition, it is reasonable to assume that for the whole delta D50 could be equal and even exceed 0.005 m). For outlet and breaching-related processes we used 0.1 m as D50 (which is used to model breaching events, e.g. in [1] and [4]).Various scenarios have been modelled; the most probable (according to our current knowledge) were analyzed.Deposition of the deltas could happen simultaneously with the last incision of corresponding valleys; the amount of carved material from last incised valleys is approximately the same as deposited in deltas.According to the modelled scenario, the eastern rim erosion lasts five times longer than the water outflow after breaching. This indicates that water discharged from the breach could not alone erode the rim and thus more water supply from inlets would be needed. However, the uncertainty of grain size calls this result into question.Another conclusion is that the northern valley alone could provide enough water (~1000 km3) during its last incision to fill the crater before breaching (446 km3). Moreover, the last incised valleys were mostly carved after the breach; if not, they would have already provided enough water to fill the crater and the breaching would have already happened.Comparison of water discharged after the breach (238 km3) with water needed to carve at least the last incision outlet valley (~4000 km3) shows that Jezero had to be an open-basin lake after breaching. References:[1] Salese, F. et al. (2020). Astrobiology, 20(8), 977–993.[2] Kleinhans, M. G. (2005). Journal of Geophysical Research: Planets, 110(12), 1–23.[3] Farley K., and Stack K. (February 15, 2023). Mars 2020 reports, Volume 2 - https://mars.nasa.gov/internal_resources/1656/[4] Roda, M. et al. (2014). Icarus, 236, 104–121.

The presence of cryovolcanic activity in the form of geyser-like plumes at Jupiter’s moon Europa is a much-debated topic. As an active plume could allow direct sampling by a passing spacecraft of a potentially habitable interior environment, the detection and analysis of ongoing plume activity would be of the highest scientific value. In the past decade, several studies have interpreted different remote and in situ observations as providing evidence for large gaseous plumes at different locations on Europa. However, definitive proof is elusive, and visible imaging data taken during spacecraft flybys do not reveal clear indications of ongoing activity. After arrival at Jupiter in 2030, the NASA Europa Clipper spacecraft will systematically search for and constrain plume activity at Europa utilizing a variety of investigations and methods during, before, and after close flybys. Given the lack of a confirmed plume detection to date, the Europa Clipper science team has adopted a global plume search strategy, not focusing on any specific geographical area or any specific type of observation. This global search strategy assigns enhanced value to data obtained early in the mission, which allows time for further observations and characterization of any observed plume at later times. Here we describe the current state of knowledge on plume activity, the Europa Clipper search strategy, and the role of various instruments on the Europa Clipper payload in this search.