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The JUpiter Icy Moon Explorer mission (JUICE) was designed to investigate Jupiter, its environment and its icy moons with at least one Europa flyby, a high inclination phase around Jupiter and a 280 days long near polar orbital phase around Ganymede, with 130 days on a low circular orbit. The goal of the JUICE mission analysis consisted in implementing these mission elements within a tight mass and radiation budget. A shift in the nominal launch date from June 2022 to September 2022 then April 2023 resulted in an arrival date at Jupiter in July 2031, close to equinox, so that the duration of eclipses by Jupiter became a major issue. A mission scheme meeting the requirements was designed using innovative approaches such as a double swing-by of the Moon and the Earth and a low energy endgame targeting a grazing Callisto flyby then grazing Ganymede encounters. Thanks to a near optimum launch date and launcher performance with full tanks, the post-launch Delta-V margins (150 m/s) made it possible to re-instate a 200 km circular orbital phase at the end of the nominal mission as planned in the mission proposal. The remaining Delta-V margin (55 m/s) and that expected from clean-up costs lower than allocated make it possible, while keeping adequate margins for contingencies, to consider significant improvements of the baseline mission scheme, in particular a higher maximum inclination during the tour and an inclination on the 200 km orbit close to Sun-synchronous, so that a long extended mission can be considered.

We here reassess the global distribution of several key mineral species using the entire OMEGA/Mars Express VIS‐NIR imaging spectrometer data set, acquired from orbit insertion in January 2004 to August 2010. Thirty‐two pixels per degree global maps of ferric oxides, pyroxenes and olivines have been derived. A significant filtering process was applied in order to exclude data acquired with unfavorable observation geometries or partial surface coverage with water and CO2 frosts. Because of strong atmospheric variations over the 3.6 Martian years of observations primarily due to the interannual variability of the aerosol opacity, a new filter based on the atmospheric dust opacity calibrated by the Mars Exploration Rovers measurements has also been implemented. The Fe3+absorption features are present everywhere on the surface, with a variety of intensities indicating distinct formation processes. The pyroxene‐bearing regions are localized in low albedo regions, while the bright regions are spectrally comparable to anhydrous nanophase ferric oxides. The expanded data set increases by a factor of about 2, the number of olivine detections reported in previous OMEGA‐based studies. Olivine is mainly detected in three types of areas over the Martian surface: discontinuous patches on the terraces of the three main basins; smooth inter‐crater plains and smooth crater floors throughout the southern highlands; and crater sand dunes, crater ejectas and extended bedrock exposures in the northern plains. Olivine is also detected in the low albedo pyroxene‐bearing dunes surrounding the northern polar cap. Key Points Global distribution of several key mineral species of the Martian surface Use of the full OMEGA data set Significant filtering process applied on data

The structure and composition of cometary constituents, down to their microscopic scale, are critical witnesses of the processes and ingredients that drove the formation and evolution of planetary bodies toward their present diversity. On board Rosetta’s lander Philae, the Comet Infrared and Visible Analyser (CIVA) experiment took a series of images to characterize the surface materials surrounding the lander on comet 67P/Churyumov-Gerasimenko. Images were collected twice: just after touchdown, and after Philae finally came to rest, where it acquired a full panorama. These images reveal a fractured surface with complex structure and a variety of grain scales and albedos, possibly constituting pristine cometary material.

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer on board the Mars Express spacecraft. These minerals are mainly associated with Noachian outcrops, which is consistent with an early active hydrological system, sustaining the long-term contact of igneous minerals with liquid water. We infer that the two main families of hydrated alteration products detected—phyllosilicates and sulphates—result from different formation processes. These occurred during two distinct climatic episodes: an early Noachian Mars, resulting in the formation of hydrated silicates, followed by a more acidic environment, in which sulphates formed. Ebb and flow The OMEGA spectrometer, orbiting on board Mars Express, is scanning the martian surface for signs of specific minerals. It has now detected a family of clays known as phyllosilicates, produced when volcanic basalt encounters water for long periods. The minerals are found mainly in rocky outcrops deposited early in martian history. The presence of a second family of sulphates suggests that there was a later, sporadically wet period, characterized by more acidic conditions.

The OMEGA visible/near‐infrared imaging spectrometer on Mars Express has observed the retreat of the northern seasonal deposits during Martian year 27–28 from the period of maximum extension, close to the northern winter solstice, to the end of the retreat at Ls 95°. We present the temporal and spatial distributions of both CO2 and H2O ices and propose a scenario that describes the winter and spring evolution of the northern seasonal deposits. During winter, the CO2‐rich condensates are initially transparent and could be in slab form. A water ice annulus surrounds the sublimating CO2 ice, extending over 6° of latitude at Ls 320°, decreasing to 2° at Ls 350°, and gradually increasing to 4.5° at Ls 50°. This annulus first consists of thin frost as observed by the Viking Lander 2 and is then overlaid by H2O grains trapped in the CO2‐rich ice layer and released during CO2 sublimation. By Ls 50°, H2O ice spectrally dominates most of the deposits. In order to hide the still several tens of centimeters thick CO2 ice layer in central areas of the cap we propose the buildup of an optically thick top layer of H2O ice from ice grains previously embedded in the CO2 ice and by cold trapping of water vapor from the sublimating water ice annulus. The CO2 ice signature locally reappears between Ls 50° and 70°. What emerges from our observations is a very active surface‐atmosphere water cycle. These data provide additional constraints to the general circulation models simulating the Martian climate. Key Points How does the spatial distribution of seasonal ices evolve during their retreat? How does the stratigraphy of seasonal deposits evolve during their retreat? How intense is the surface‐atmosphere water cycle during northern spring?

The characterization of objects that have best preserved the mineralogical and molecular phases formed in the earliest stages of the Solar System evolution is key to understanding the processes that led to the formation of the planets in their diversity. The Hayabusa2 mission of the Japan Aerospace Exploration Agency has returned for the first time samples collected at the surface of a C-type asteroid, Ryugu 1 , 2 . They are now preserved at the Extraterrestrial Samples Curation Center of the Japan Aerospace Exploration Agency at the Institute of Space and Astronautical Science in Sagamihara, Japan, where they are submitted to a first round of purely non-destructive analyses. The MicrOmega hyperspectral microscope developed at the Institut d'Astrophysique Spatiale (Orsay, France), which operates in the near-infrared range (0.99–3.65 µm), is performing their mineralogical and molecular characterization down to the scale of a few tens of micrometres. Strong features at 2.7 µm (indicating their OH-rich content) and at 3.4 µm (diagnostic of the presence of organics) dominate at a global scale, but key distinctive signatures have been identified at a submillimetre scale. In particular, carbonates (a fraction of them enriched in iron) as well as NH-rich compounds have been detected. The occurrence of volatile-rich species, likely originating from the outer Solar System, would support Ryugu having preserved both pristine material and altered phases, which are now available for refined laboratory analyses with the potential to draw new insights into the formation and evolution paths of planetary bodies in our Solar System. The MicrOmega imaging spectrometer performed a first characterization of the sample returned from asteroid Ryugu by Hayabusa2. Compositional homogeneity dominates down to millimetre scales, with signatures of hydrated phases and organics. At the submillimetre scale, NH-rich compounds and alteration products such as carbonates are detected.

The samples returned from asteroid Ryugu were collected both at its surface and at its subsurface by Hayabusa2 and can, thus, provide information on the space weathering of C-type asteroids at different depths without terrestrial contamination. The near-infrared hyperspectral microscope MicrOmega gathered data on the –OH feature at ~2.7 μm for 177 individual grains from the two collection sites. Here, through a spectral analysis of these data, we show that the position of the band peak can be used as an indicator of the degree of space weathering. Most subsurficial grains do not present space weathering features, indicating that Ryugu’s subsurface layers have never been exposed to the interplanetary medium. Moreover, the ~2.7 μm feature for the Ryugu samples is narrower than that observed for CI chondrites, which are the closest meteorite analogues to Ryugu, suggesting that these contain more absorbed molecular water than Ryugu due to terrestrial aqueous contamination. We conclude that Ryugu samples should be considered as a reference for the primordial water abundance within primitive bodies.A statistical study of the ~2.7 µm hydration band in the Ryugu samples shows that Ryugu’s immediate subsurface has not been exposed to space weathering and that even the pristine CI chondrites exhibit terrestrial contamination, making the Hayabusa2 samples a reference for primitive water abundance in carbonaceous asteroids.

The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) investigation, on board the European Space Agency Mars Express mission, is mapping the surface composition of Mars at a 0.3- to 5-kilometer resolution by means of visible-near-infrared hyperspectral reflectance imagery. The data acquired during the first 9 months of the mission already reveal a diverse and complex surface mineralogy, offering key insights into the evolution of Mars. OMEGA has identified and mapped mafic iron-bearing silicates of both the northern and southern crust, localized concentrations of hydrated phyllosilicates and sulfates but no carbonates, and ices and frosts with a water-ice composition of the north polar perennial cap, as for the south cap, covered by a thin carbon dioxide-ice veneer.

Datafromthe Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) on the Mars Express spacecraft identify the distinct mafic, rock-forming minerals olivine, low-calcium pyroxene (LCP), and high-calcium pyroxene (HCP) on the surface of Mars. Olivine- and HCP-rich regions are found in deposits that span the age range of geologic units. However, LCP-rich regions are found only in the ancient Noachian-aged units, which suggests that melts for these deposits were derived from a mantle depleted in aluminum and calcium. Extended dark regions in the northern plains exhibit no evidence of strong mafic absorptions or absorptions due to hydrated materials.