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International audience; The Perseverance rover landed on the floor of Jezero crater in February 2021. The initial set of images taken from the landing site of the residual butte Kodiak showed a deltaic architecture consistent with a paleolake, but at a level ~100 m lower than expected, suggestive of a closed lake system. After spending ~1 year studying the crater floor, the rover reached the front of the deltaic fan in April 2022. Here, we report observations of the facies, structure and composition of these sedimentary deposits using the SuperCam instrument. SuperCam can take images for texture analysis with the Remote Micro-Imager (RMI), visible and infrared reflectance (VISIR) spectra as well as Raman spectra for mineralogical analysis, and data from laser induced breakdown spectroscopy (LIBS) for chemical analysis. The rover investigated the basal strata of the delta along two traverses at the SE of the delta front. The transition between the crater floor and the delta is not well determined due to regolith and strongly degraded outcrops, and is currently under assessment. The ~20 m thick basal layers that are well-visible on orbital data consist of fine-grained sandstones and siltstones deposited in sub-horizontal planar beds with millimeter thick laminations. These deposits display a substantial alteration highlighted by the detection of both sulfates and phyllosilicates, with exception of local boulders of igneous texture lacking alteration. Texture and composition are both consistent with a quiet regime of deposition such as in lake deposits or distal delta slopes. These beds are considered of topmost importance for sample return and were cored in two locations. Pebbly sandstones and conglomerates with pebbles limited to a few centimeters are observed immediately above these strata. The texture is matrix-supported suggesting an emplacement through gravity sliding or turbidity flows below water rather than fluvial deposition. The composition is more variable than in underlying finer-grained beds and includes local carbonate detections. Uppermost deposits have not been reached by the rover yet, but have been analyzed remotely by RMI images, and VISIR for some of them. They consist of cross-bedded sandstones and conglomerates in all locations of the delta front. The diversity in texture of these deposits suggests a variability in depositional regimes including high-energy floods, either during the lacustrine phase, or subsequently. Boulders present within these layers are rounded suggesting a substantial abrasion by fluvial transport. These boulders are also interesting targets for sampling distant crustal rocks. The top of the delta will be analyzed and sampled along the traverse of the rover in 2023.

ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 $\mu$m), and sub-millimetre sounding (near 530-625\,GHz and 1067-1275\,GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet., Comment: 83 pages, 24 figures, submitted to Space Science Reviews special issue on ESA's JUICE mission

We examine the observed properties of the Nili Fossae olivine-clay-carbonate lithology from orbital data and in situ by the Mars 2020 rover at the Séítah unit in Jezero crater, including: 1) composition (Liu, 2022) 2) grain size (Tice, 2022) 3) inferred viscosity (calculated based on geochemistry collected by SuperCam (Wiens, 2022)). Based on the low viscosity and distribution of the unit we postulate a flood lava origin for the olivine-clay-carbonate at Séítah. We include a new CRISM map of the clay 2.38 μm band and use in situ data to show that the clay in the olivine cumulate in the Séítah formation is consistent with talc or serpentine from Mars 2020 SuperCam LIBS and VISIR and MastCam-Z observations. We discuss two intertwining aspects of the history of the lithology: 1) the emplacement and properties of the cumulate layer within a lava lake, based on terrestrial analogs in the Pilbara, Western Australia, and using previously published models of flood lavas and lava lakes, and 2) the limited extent of post emplacement alteration, including clay and carbonate alteration (Clave, 2022; Mandon, 2022)., 34 pages, 15 figures

We report on results of an observing campaign to support the Juno mission. At the beginning of 2016, using TEXES (Texas Echelon cross-dispersed Echelle Spectrograph), mounted on the NASA Infrared Telescope Facility (IRTF), we obtained data cubes of Jupiter in the 1930--1943 cm$^{-1}$ spectral ranges (around 5 $��$m), which probe the atmosphere in the 1--4 bar region, with a spectral resolution of $\approx$ 0.15 cm$^{-1}$ and an angular resolution of $\approx$ 1.4". This dataset is analysed by a code that combines a line-by-line radiative transfer model with a non-linear optimal estimation inversion method. The inversion retrieves the vertical abundance profiles of NH$_3$ - which is the main contributor at these wavelengths - with a maximum sensitivity at $\approx$ 1--3 bar, as well as the cloud transmittance. This retrieval is performed on over more than one thousand pixels of our data cubes, producing maps of the disk, where all the major belts are visible. We present our retrieved NH$_3$ abundance maps which can be compared with the distribution observed by Juno's MWR (Bolton et al., 2017; Li et al., 2017) in the 2 bar region and discuss their significance for the understanding of Jupiter's atmospheric dynamics. We are able to show important latitudinal variations - such as in the North Equatorial Belt (NEB), where the NH$_3$ abundance is observed to drop down to 60 ppmv at 2 bar - as well as longitudinal variability. In the zones, we find the NH$_3$ abundance to increase with depth, from 100 $\pm$ 15 ppmv at 1 bar to 500 $\pm$ 30 ppmv at 3 bar. We also display the cloud transmittance--NH$_3$ abundance relationship, and find different behaviour for the NEB, the other belts and the zones. Using a simple cloud model, we are able to fit this relationship, at least in the NEB, including either NH$_3$-ice or NH$_4$SH particles with sizes between 10 and 100 $��$m., 21 pages, 15 figures, 4 tables, preprint accepted by Icarus the 04 June 2018

International audience

Remote sensing observations suffer significant limitations when used to study the bulk atmospheric compositionof the giant planets of our solar system. This impacts our knowledge of the formation of these planets andthe physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements wasillustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’abundances and the precise measurement of the helium mixing ratio were only made available through in situmeasurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the futurein situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broadercontext. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) theformation history of the giant planets and that of the Solar System, and ii) the processes at play in planetaryatmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, withdata returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could representa significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn,Uranus, and/or Neptune.