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Introduction: The Ryugu samples brought back by the Hayabusa2 spacecraft in December 2020 have been delivered to the JAXA Extraterrestrial Curation Center [1]. Bulk samples and then individual grains have been picked up and stored into sapphire dishes, weighted, and analyzed with an optical microscope, FTIR spectroscopy, and MicrOmega hyperspectral imaging [2-4] for initial description. The MicrOmega instrument used in the JAXA Extraterrestrial Curation Center is a near-infrared (NIR) hyperspectral microscope [5]. It has a total field of view of ~5 mm x 5 mm, with a resolution of ~22 µm/pixel in the focal plane. It covers the spectral domain from 0.99 µm to ~3.6 µm, enabling the identification of most candidate minerals and molecules of relevance (e.g. mafic minerals, altered phases, salts, ices, aliphatic/aromatic CH, NH-rich compounds) [6]. In particular, in the spectral domain of MicrOmega, carbonates have a strong characteristic double absorption band in the 3.3-3.5 µm range, accompanied by two other weaker bands around 2.5 and 2.3 µm. The exact position of these bands varies with the cation content of the carbonate [7]. Iron-bearing carbonates also show a strong Fe2+ absorption below 1.5 µm. Initial analyses with MicrOmega were first made on the bulk samples from chambers A and C of the Hayabusa 2 returned capsule, and then on individual grains stored in their sapphire dishes (by the end of 2021, ~180 individual grains have been analyzed), as well as 14 sub-bulks. Such extensive characterization provides a unique opportunity to assess the different processes that shaped Ryugu's material. Here, we focus on the MicrOmega analyses of Ryugu carbonate-rich grains and inclusions which record the alteration processes encountered on Ryugu parent body. Results: Spectra of the Ryugu samples at the mm-scale share common features: a very low reflectance (2-3%), an absorption band centered around 2.715 µm attributed to OH, and a weak absorption centered around 3.4 µm attributed to a variety of CH-rich compounds and carbonates [2]. Only at a sub-millimeter scale do heterogeneities clearly show up, either or both at grain level or as inclusions within grains. In total, more than 200 carbonate-rich areas larger than ~45 µm (2x2 MicrOmega pixels) have been detected among the grains and bulks/sub-bulks observed with MicrOmega by the end of 2021 (which does not preclude the presence of carbonates at finer scale). While most of the detections are smaller than ~100 µm in size, the largest carbonate-rich areas can reach several hundreds of µm, displaying various kinds of morphologies. The analysis of the position of the absorption features enabled the identification of various types of carbonates, similar to dolomite and breunnerite for the large majority of them. These various detections and the context in which they are made will be presented. Implications for the alteration processes encountered on Ryugu's parent body will also be discussed. [ABSTRACT FROM AUTHOR]

Introduction: On December 6, 2020, the Hayabusa2 mission successfully returned to Earth ~ 5.4 g of samples collected at the surface of the C-type asteroid Ryugu [1,2]. Its surface was first sampled on February 22, 2019 ("bulk A"), then on July 11, 2019, close to a 15-meter large artificial crater, so as to possibly access sub-surface material ("bulk C") [3]. The collected samples are now kept at ISAS (Institute of Space and Astronautical Science) for a first round of preliminary analyses, with the objective of characterizing in a non-destructive manner both the bulk samples and a few hundreds of grains extracted from them [4]. In particular, the goal is 1) to support their further detailed characterization by the international Initial Analysis Teams, and 2) to build a catalogue of the grains, accessible to the international community through AO selection, starting mid-2022. Importantly, the analyzed samples have always been kept, since their collection, in a fully clean and controlled environment either under vacuum or ultra-clean GN2. Methods: The preliminary characterization of these samples is being conducted with a visible microscope with six color filters [4], a FTIR spectrometer (1-4 μm) [4], and MicrOmega, a hyperspectral microscope [5], operating in the near-infrared range (0.99-3.65 μm) where diagnostic signatures of most candidate minerals and molecules of relevance (e.g. mafic minerals, altered phases, salts, ices, aliphatic/aromatic CH, NH-rich compounds) can be found. For each 22.5x22.5 μm² pixel of the 250x256 pixels² field of view, the reflectance spectrum is retrieved in up to 400 contiguous spectral channels. Both the negligible amount of illuminating power at less than 10-8 W/px and the lack of contact with the samples allow entirely non-destructive and non-invasive characterization. By the beginning of 2022, bulk samples from chamber A and chamber C of the Hayabusa2 returned capsule (each divided into 3 sub-bulks), as well as >200 individual grains and 14 "small-bulks" extracted from them have been analyzed with MicrOmega. Results: When analyzed at the mm-scale by averaging thousands of pixels, the spectra of bulk A and bulk C exhibit a pattern similar to those acquired remotely down to the meter scale by the NIRS3 IR spectrometer on board Hayabusa2 [6]. The global reflectance is extremely low, 2-3 %, in agreement with the measurements of the ONCs and NIRS3 at Ryugu [7,8], and consistent with the taxonomic spectral classification of Ryugu as a C-type asteroid [1,2]. The main spectral feature is the diagnostic OH absorption centered at 2.715 +/-0.005 μm, position compatible with that of NIRS3 spectra [8,9]. No significant differences can be observed between bulk A and bulk C for this specific feature. MicrOmega spectra also exhibit a broad feature in the 3.3-3.5 μm range, centered around 3.4 μm, present throughout the sub-bulk samples. This feature is considered indicative of the large-scale presence of a variety of CHrich compounds and carbonates. A fainter ~3.1 μm broad feature, indicative of the presence of NH-bearing compounds is also detected, although with varying and much fainter intensities. Only at a sub-millimeter scale do heterogeneities clearly show up, either or both at grain level or as inclusions within grains. Detections include for example: 1) carbonates of various compositions, detected on a rather large number of occurrences with sizes ranging from a few tens to a few hundreds of micrometers [10]; 2) spots enriched in organics, in particular through a 3.4 μm feature indicative of the presence of aliphatic compounds; 3) spots enriched in a nitrogen-rich phase, through a ~3.1 μm feature sometimes coupled to additional spectral features. These detections, as well as others, will be presented and candidates will be discussed. Noticeably, no chondrules nor refractory inclusions have been identified yet. Conclusion: The initial spectral characterization of the returned samples by MicrOmega currently points towards Ryugu containing a fascinating variety of grains, including OH-, CH- and NH- rich compounds spread at a global scale, and alteration products, among which highly diagnostic carbonates. The occurrence of volatile-rich species, likely originating from the outer solar system, would support Ryugu having preserved some of its building blocks, together with their partially altered phases. The Hayabusa2 returned samples, thus, appear among the most primordial material available in our laboratories. [ABSTRACT FROM AUTHOR]

Introduction: The organic content of chondrites has been widely analyzed after chemical extraction and separation into soluble [e.g. 1] and insoluble phases [e.g. 2, 3, 4] but much less studied "in situ", i.e. directly in the meteorite bulk, keeping intact its mineral environment [e.g. 5, 6]. In this study, we present a Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) analysis of samples of 2 differently altered CM chondrites. TOF-SIMS gives information about the composition and the structure of the organic and mineral compounds detected on the sample surface analyzed. It has already been successfully used to study the organic content of extraterrestrial samples [7,6,8]. Our purpose is more precisely, to study the variations in the chemical structures and localizations of the organic content depending on the aqueous alteration context of each CM sample measured, in order to better understand the different steps of hydrothermal processes that affected the parent asteroids. Materials and Methods: We analyzed freshly cut millimetric slices of 2 CM chondrites (see [9] for the preparation protocol): Cold Bokkeveld (CM2.2 [10]) and Paris (CM2.7-2.9 [11,12]). The slices, previously analyzed by IR reflectance hyperspectral imaging and Raman spectroscopy [9], were measured by TOF-SIMS 2D imaging with an ION-TOF V mass spectrometer, following a protocol optimized in a previous study [6]. The measurements were carried out on areas of 500x500 μm² with a spatial resolution of 2 μm per pixel. After a cleaning with argon clusters (Ar1300-1900), the surfaces were analyzed by a Bi3 + cluster beam at 25 keV. An ordinary chondrite, Tuxtuac (LL5 [13]), was also prepared and analyzed in the same conditions and used as a control sample. Results and discussion: We obtained maps displaying the distribution of different types of organic compounds and fragments on the chondrite samples measured. These maps strongly confirm the IR and Raman preliminary analysis [9]. They show that the organic species are present throughout the matrix and the chondrules of Cold Bokkeveld, except in carbonate and sulfate-rich regions, whereas they are mostly concentrated in the phyllosilicaterich matrix, generally next to chondrules, in Paris samples. Comparison of the samples' mass spectra also provides information about the variations in the unsaturation degree or carbon chain length. Indeed, we found that Cold Bokkeveld exhibits a lower average H/C ratio than Paris for hydrocarbon fragments containing at least 3 carbons. This result implies an increase of the unsaturation degree with increasing alteration. It is consistent with the trend observed by Alexander et al. [14] for insoluble organic matter extracted from differently altered regions of Tagish Lake (C2), and suggests that organic compounds are affected by aromatization and/or crosslinking during aqueous alteration. Based also on our study of heteroatom-containing fragments, we will discuss the evolution stages undergone by organic matter during hydrothermal alteration of CMs. Acknowledgments: We thank B. Zanda and the Museum National d'Histoire Naturelle (MNHN, Paris) for providing us with the Paris meteorite sample and L. Bonal for providing us with the Tuxtuac meteorite sample. The Cold Bokkeveld meteorite sample was provided by the Vatican Observatory. We also thank V. Huc (ICMMO, Orsay, France), J. Bettane and B. Mathon (IJClab, Orsay, France) for specific sample holder developments, and J.P. Salvetat (PLACAMAT, Bordeaux, France) for part of the measurements. This work has been funded by the CLASSY project (Grant ANR-17-CE31-0004-02) of the French Agence Nationale de la Recherche. [ABSTRACT FROM AUTHOR]

Introduction: In December 2020, the Hayabusa2 reentry capsule returned 5.4 g of material from the asteroid Ryugu. A fraction of the collected material was then examined by Initial Analysis Teams. As a part of the Mineralogy / Petrology STONE team, we received ~30 small fragments to study the 3D heterogeneity and the assembly of the different phases. Material and methods: In this study, we will present the results of a muti-analytical sequence applied to nine micrometric Ryugu fragments (ranging from 30 to 80 µm in size), coming from 3 bigger millimetric grains (A0064, C0046, and C0002). These fragments were welded with platinum on metallic needles using FIB (Focus Ion Beam) microscopes in Saclay and Lille [1]. Then, we analyzed these fragments using an IR micro-tomography setup available at the SMIS beamline of the SOLEIL synchrotron (France). Multiple configurations were used: analyses in transmission by Infrared Computed Tomography [2] (IR-CT) and analyses in reflectance by Infrared Surface Imaging [3] (IRSI). Regions of interest with peculiar spectral signatures were identified on the 3D volume and 3-µm thin-slices (~ 15 x 20 x 3 µm³) around these regions were extracted using FIB. They were finally analyzed in 2D with high-resolution IR imaging and SEM-EDX. Average composition: We will present the average IR spectra in the 2.5 - 12.5 µm range both in reflectance and transmission of the 9 small studied fragments. Several grains showed IR signatures at ~ 2.7 µm, 3.0-3.1 µm, 3.4 µm, and 3.9 µm, in a good agreement with the bands identified by NIRS3 or by MicrOmega in the JAXA curation facility [4,5], plus several mid-IR signatures of great interest, such as bands attributed to Si-O stretching in phyllosilicates, and C=O stretching in organics and carbonates. In general, the 2.7 µm feature observed in our data exhibits similar maximum position but is deeper to the one observed with NIRS3. However, we notice a variability of the composition between the 9 fragments, for instance in the intensity of the 2.7 and 3.4 µm features. Study of heterogeneity: The small fragment C0002-FO019, exhibits two regions with very different IR signatures. The difference in the position and the shape of the SiO feature could sign different lithologies affected by various degrees of aqueous alteration. In particular, some spectra show a shoulder at ~ 998 cm-1 which could be due to anhydrous silicate related to a less-altered lithology [6]. The origin of the variation of the 10 µm band (chemical composition, or structural diversity of the mineral) will be discussed. A correlation with the 2.7 µm band will also be presented. Complementary measurements performed with SEM-EDX to better constrain the mineralogy of the surface of the extracted thin-slices will be presented and we will discuss the structural diversity at the scale of ~100 nm. [ABSTRACT FROM AUTHOR]

Interstellar ices are widely observed in the infrared spectra of regions where stars and planetary systems form. Photochemical and thermal evolution of these ices is simulated and studied in our laboratory where the resulting production of complex organic residues is routinely performed. Observations of their variability with slightly different starting chemical conditions can be performed by means of infrared spectroscopy. Organic residues have interesting chemical properties that make them good potential candidates for prebiotic chemistry. Numerous other analytical methods (GC-MS, HPLC, mass spectrometry, etc.) can be combined to refine the knowledge of their chemical composition and structure. We present here some results on the obtained organic residue resulting from subsequent heating and sublimation of the irradiated ices which show the formation of some macromolecular species. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is a non-destructive analytical technique for characterizing organic and inorganic materials with spatial resolution in the micrometer range. This makes it a method of choice for space-mission sample characterization, whether on return or in situ. To enhance its sensitivity, we use signal amplification via interaction with plasmonic silver-based colloids, which corresponds to surface-enhanced Raman scattering (SERS). In this study, we focus on the analysis of biomolecules of prebiotic interest on extraterrestrial dust trapped in silica aerogel, jointly with the Japanese Tanpopo mission. The aim is twofold: to prepare samples as close as possible to the real ones, and to optimize analysis by SERS for this specific context. Serpentinite was chosen as the inorganic matrix and adenine as the target biomolecule. The dust was projected at high velocity into the trapping aerogel and then mechanically extracted. A quantitative study shows effective detection even for adenine doping from a 5·10 -9 mol/L solution. After the dust has been expelled from the aerogel using a solvent, SERS mapping enables unambiguous adenine detection over the entire dust surface. This study shows the potential of SERS as a key technique not only for return samples, but also for upcoming new explorations.

The instrument COSIMA (COmetary Secondary Ion Mass Analyzer) onboard of the European Space Agency mission Rosetta collected and analyzed dust particles in the neighborhood of comet 67P/Churyumov-Gerasimenko. The chemical composition of the particle surfaces was characterized by time-of-flight secondary ion mass spectrometry. A set of 2213 spectra has been selected, and relative abundances for CH-containing positive ions as well as positive elemental ions define a set of multivariate data with nine variables. Evaluation by complementary chemometric techniques shows different compositions of sample groups collected during two periods of the mission. The first period was August to November 2014 (far from the Sun); the second period was January 2015 to February 2016 (nearer to the Sun). The applied data evaluation methods consider the compositional nature of the mass spectral data and comprise robust principal component analysis as well as classification with discriminant partial least squares regression, k -nearest neighbor search, and random forest decision trees. The results indicate a high importance of the relative abundances of the secondary ions C + and Fe + for the group separation and demonstrate an enhanced content of carbon-containing substances in samples collected in the period with smaller distances to the Sun., (© 2020 The Authors. Journal of Chemometrics published by John Wiley & Sons Ltd.)

This study is a multi-technique investigation of the Paris carbonaceous chondrite directly applied on two selected 500 × 500 µm² areas of a millimetric fragment, without any chemical extraction. By mapping the partial hydration of the amorphous silicate phase dominating the meteorite sample matrix, infrared spectroscopy gave an interesting glimpse into the way the fluid may have circulated into the sample and partially altered it. The TOF-SIMS in-situ analysis allowed the studying and mapping of the wide diversity of chemical moieties composing the meteorite organic content. The results of the combined techniques show that at the micron scale, the organic matter was always spatially associated with the fine-grained and partially-hydrated amorphous silicates and to the presence of iron in different chemical states. These systematic associations, illustrated in previous studies of other carbonaceous chondrites, were further supported by the identification by TOF-SIMS of cyanide and/or cyanate salts that could be direct remnants of precursor ices that accreted with dust during the parent body formation, and by the detection of different metal-containing large organic ions. Finally, the results obtained emphasized the importance of studying the specific interactions taking place between organic and mineral phases in the chondrite matrix, in order to investigate their role in the evolution story of primitive organic matter in meteorite parent bodies.

The in situ cometary dust particle instrument COSIMA (COmetary Secondary Ion Mass Analyser) onboard ESA's Rosetta mission has collected about 31 000 dust particles in the inner coma of comet 67P/Churyumov-Gerasimenko since August 2014. The particles are identified by optical microscope imaging and analysed by time-of-flight secondary ion mass spectrometry. After dust particle collection by low speed impact on metal targets, the collected particle morphology points towards four families of cometary dust particles. COSIMA is an in situ laboratory that operates remotely controlled next to the comet nucleus. The particles can be further manipulated within the instrument by mechanical and electrostatic means after their collection by impact. The particles are stored above 0°C in the instrument and the experiments are carried out on the refractory, ice-free matter of the captured cometary dust particles. An interesting particle morphology class, the compact particles, is not fragmented on impact. One of these particles was mechanically pressed and thereby crushed into large fragments. The particles are good electrical insulators and transform into rubble pile agglomerates by the application of an energetic indium ion beam during the secondary ion mass spectrometry analysis.This article is part of the themed issue 'Cometary science after Rosetta'., (© 2017 The Author(s).)

The presence of solid carbonaceous matter in cometary dust was established by the detection of elements such as carbon, hydrogen, oxygen and nitrogen in particles from comet 1P/Halley. Such matter is generally thought to have originated in the interstellar medium, but it might have formed in the solar nebula-the cloud of gas and dust that was left over after the Sun formed. This solid carbonaceous material cannot be observed from Earth, so it has eluded unambiguous characterization. Many gaseous organic molecules, however, have been observed; they come mostly from the sublimation of ices at the surface or in the subsurface of cometary nuclei. These ices could have been formed from material inherited from the interstellar medium that suffered little processing in the solar nebula. Here we report the in situ detection of solid organic matter in the dust particles emitted by comet 67P/Churyumov-Gerasimenko; the carbon in this organic material is bound in very large macromolecular compounds, analogous to the insoluble organic matter found in the carbonaceous chondrite meteorites. The organic matter in meteorites might have formed in the interstellar medium and/or the solar nebula, but was almost certainly modified in the meteorites' parent bodies. We conclude that the observed cometary carbonaceous solid matter could have the same origin as the meteoritic insoluble organic matter, but suffered less modification before and/or after being incorporated into the comet.

Comets are composed of dust and frozen gases. The ices are mixed with the refractory material either as an icy conglomerate, or as an aggregate of pre-solar grains (grains that existed prior to the formation of the Solar System), mantled by an ice layer. The presence of water-ice grains in periodic comets is now well established. Modelling of infrared spectra obtained about ten kilometres from the nucleus of comet Hartley 2 suggests that larger dust particles are being physically decoupled from fine-grained water-ice particles that may be aggregates, which supports the icy-conglomerate model. It is known that comets build up crusts of dust that are subsequently shed as they approach perihelion. Micrometre-sized interplanetary dust particles collected in the Earth's stratosphere and certain micrometeorites are assumed to be of cometary origin. Here we report that grains collected from the Jupiter-family comet 67P/Churyumov-Gerasimenko come from a dusty crust that quenches the material outflow activity at the comet surface. The larger grains (exceeding 50 micrometres across) are fluffy (with porosity over 50 per cent), and many shattered when collected on the target plate, suggesting that they are agglomerates of entities in the size range of interplanetary dust particles. Their surfaces are generally rich in sodium, which explains the high sodium abundance in cometary meteoroids. The particles collected to date therefore probably represent parent material of interplanetary dust particles. This argues against comet dust being composed of a silicate core mantled by organic refractory material and then by a mixture of water-dominated ices. At its previous recurrence (orbital period 6.5 years), the comet's dust production doubled when it was between 2.7 and 2.5 astronomical units from the Sun, indicating that this was when the nucleus shed its mantle. Once the mantle is shed, unprocessed material starts to supply the developing coma, radically changing its dust component, which then also contains icy grains, as detected during encounters with other comets closer to the Sun.