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Evidence of liquid water is a primary indicator of habitability on the icy moons in our outer solar system as well as on terrestrial planets such as Mars. If liquid water-containing environments host life, some of its organic remains can be fossilized and preserved as organic biosignatures. However, inorganic materials may also be present and water-assisted organic-inorganic reactions can transform the organic architecture of biological remains. Our understanding of the fate of these organic remains can be assisted by experimental simulations that monitor the chemical changes that occur in microbial organic matter due to the presence of water and minerals. We performed hydrothermal experiments between 100–300°C involving lipid-rich microbes and natural serpentinite mineral mixtures generated by the subaqueous hydrothermal alteration of ultramafic rock. The products reveal what the signals of life may look like when subjected to water-organic-inorganic reactions. Straight and branched chain lipids in unaltered samples are joined by cyclization and aromatization products in hydrothermally altered samples. Hydrothermal reactions produce distinct products that are not present in the starting materials including small, single-ring, heteroatomic and aromatic compounds such as indoles and phenols. Hydrothermal reactions in the presence of serpentinite minerals lead to the significant reduction of these organic structures and their replacement by diketopiperazines (DKPs) and dihydropyrazines (DHPs), which may be compounds that are distinct to organic-inorganic reactions. Given that the precursors of DKPs and DHPs are normally lost during early diagenesis, the presence of these compounds can be an indicator of co-existing recent life and hydrothermal processing. However, the thermal stability of these compounds reveals that the formation and preservation of these compounds only occurs within a distinct temperature window. Serpentinite is also found to have a preservative effect on some compounds, such as alkylamides. Our findings are relevant to life detection missions that aim to access hydrothermal and serpentinizing environments in the subsurfaces of icy moons and Mars.

Executive summary provided in lieu of abstract., SCOPUS: no.j, info:eu-repo/semantics/published

Planetary noble gases in chondrites are concentrated in an unidentified carrier phase, called “Q.” Phase Q oxidized at relatively low temperature in pure oxygen is a very minor part of insoluble organic matter (IOM), but has not been separated in a pure form. High‐pressure (HP) experiments have been used to test the effects of thermal metamorphism on IOM from the Orgueil (CI1) meteorite, at conditions up to 10 GPa and 700 °C. The effect of the treatment on carbon structural order was characterized by Raman spectroscopy of the carbon D and G bands. The Raman results show that the IOM becomes progressively more graphite‐like with increasing intensity and duration of the HP treatment. The carbon structural transformations are accompanied by an increase in the release temperatures for IOM carbon and 36Ar during stepped combustion (the former to a greater extent than the latter for the most HP treated sample) when compared with the original untreated Orgueil (CI1) sample. The 36Ar/C ratio also appears to vary in response to HP treatment. Since 36Ar is a part of Q, its release temperature corresponds to that for Q oxidation. Thus, the structural transformations of Q and IOM upon HP treatment are not equal. These results correspond to observations of thermal metamorphism in the meteorite parent bodies, in particular those of type 4 enstatite chondrites, e.g., Indarch (EH4), where graphitized IOM oxidized at significantly higher temperatures than Q (Verchovsky et al. 2002). Our findings imply that Q is less graphitized than most of the macromolecular carbonaceous material present during parent body metamorphism and is thus a carbonaceous phase distinct from other meteoritic IOM.

All missions to Mars which have attempted to detect organic molecules have detected simple chlorohydrocarbons, the source of which has yet to be firmly established. This study assessed the likelihood of these chlorinated molecules being indigenous to the sedimentary units in which they were detected or if they were chlorinated during analysis. The survivability of 1-chloronapthalene was examined via hydrous pyrolysis experiments and its de-chlorination kinetics were determined. The results of these experiments were used to model the survivability of this simple chlorohydrocarbon under Mars-relevant diagenetic conditions using the Sheepbed mudstone unit as a case study. It was found that 1-chloronapthalene was rapidly dechlorinated under Noachian conditions and thus the detected Martian chlorohydrocarbons are unlikely to be ancient and probably formed within the rover’s sample handling chain during analysis.

Executive Summary: Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team (iMOST). The purpose of the team is to re-evaluate and update the sample-related science and engineering objectives of a Mars Sample Return (MSR) campaign. The iMOST team has also undertaken to define the measurements and the types of samples that can best address the objectives. Seven objectives have been defined for MSR, traceable through two decades of previously published international priorities. The first two objectives are further divided into sub-objectives. Within the main part of the report, the importance to science and/or engineering of each objective is described, critical measurements that would address the objectives are specified, and the kinds of samples that would be most likely to carry key information are identified. These seven objectives provide a framework for demonstrating how the first set of returned martian samples would impact future martian science and exploration. They also have implications for how analogous investigations might be conducted for samples returned by future missions from other solar system bodies, especially those that may harbor biologically relevant or sensitive material, such as Ocean Worlds (Europa, Enceladus, Titan) and others.

Evidence of habitability and habitation of Mars may be forthcoming by returning samples to Earth [1]. Clear objectives and associated choices of samples is essential to maximize the opportunities presented by returned samples. In the context of the solar system, the relative similarity of Earth and Mars generates an expectation of biochemical harmony for Earth and Mars. We can confidently predict that any biochemical scaffolding on Mars would be based on carbon and any biochemical solvent would be based on water. To expect otherwise would require planetary conditions and chemistries [2] that differ dramatically from those of either Earth or Mars. Reduced carbon is therefore a beacon for the potential discovery of evidence of life in a sample [3]. Any reduced carbon detected in samples from Mars should also have features that provide the ability to discriminate between non-life and life sources and, preferably, between an origin on Earth and Mars. For detecting life, the usefulness of organic carbon to biochemistry is in its ability to form complex and specific organic structures. Recognizing the organic signatures of life is therefore an achievable goal. For discriminating provenance on Earth and Mars, detailed environmental adaptions must be sought. Although based on carbon and water the biochemical similarities between organisms on Earth and Mars would not be expected to be exact. Our terrestrial examples of environmental adaptations reveal substantial biochemical variations that reflect the challenges and opportunities presented by the host environment 3. This is a provisional report from the iMOST subteam on the objective of Seeking the Signs of Life, identifying key samples and measurements needed to understand Martian Organic Carbon.

Introduction: With the increasing evidences of the presence of liquid water in the outer solar system, the number of potential habitable environment increases, as a consequence, the issue of contaminating these en-vironments is more and more important and relevant. There are currently six ongoing missions to the outer solar system and small bodies and the main space agencies are currently planning several exploration missions to the outer solar system (in particular aster-oids and the Jovian system).

Impact ejected rocks are targets for life detection missions to Mars. The Martian subsurface is more favourable to organic preservation than the surface owing to an attenuation of radiation and physical separation from oxidising materials with increasing depth. Impact events bring materials to the surface where they may be accessed without complicated drilling procedures. On Earth, different assemblages of organic matter types are derived from varying depositional environments. Here we assess whether these different types of organic materials can survive impact events without corruption. We subjected four terrestrial organic matter types to elevated pressures and temperatures in piston-cylinder experiments followed by chemical characterisation using whole-rock pyrolysis-gas chromatography-mass spectrometry. Our data reveal that long chain hydrocarbon-dominated organic matter (types I and II; mainly microbial or algal) are unresistant to pressure whereas aromatic hydrocarbon-dominated organic matter types (types III and IV; mainly land plant, metamorphosed or degraded, displaying some superficial chemical similarities to abiotic meteoritic organic matter) are relatively resistant. This suggests that the impact excavated record of potential biology on Mars will be unavoidably biased, with microbial organic matter underrepresented while metamorphosed, degraded or abiotic meteoritic organic matter types will be selectively preserved.

The OREOcube experiment will use in situ spectroscopy to study minerals and organic compounds exposed to LEO radiation conditions on an ISS external platform.

Organic compounds that survive in uncommon space environments are animportant astrobiology focus. The ORganics Exposure in Orbit (OREOcube)experiment will investigate, in real time, chemical changes in organiccompounds exposed to low Earth orbit radiation conditions on anInternational Space Station (ISS) external platform. OREOcube ispackaged as an identical pair of 10-cm cube instruments, each weighing

A number of marine sequences across the K/Pg boundary have been identified that offer reasonably continuous records and relatively high sedimentation rates, most notably those near Tethyan continental margins. However, few Eastern Tethys K/Pg localities have been studied compared to the well-known North African and Southern European sites. Here we present a high-resolution stable carbon isotope and palynological record of a 2m thick section across the K/Pg boundary from the eastern Tethys at Sumbar in Turkmenistan (38°28’N, 56°14’E). The stratigraphy and inorganic geochemistry of the section used in this study, SM-4, has been described in detail by [1].

Introduction: The nature of the planetary noble gas carrier (Q) in meteorites remains uncertain. It is known that it is likely to be carbonaceous, but represents only a small fraction of the total macromolecular material. Q is oxidisible with nitric and other oxidizing acids. It seems to be partly destroyed with pyridine and may have an organic structure. Previously, we have shown that during parent body thermal metamorphism Q is less affected than the majority of other carbonaceous materials. If organic matter is graphitized, as has happened in the enstatite chondrite parent bodies, Q remains unaffected. In the present study we have found that Q is also separable from the majority of carbon in type 2 and 3 CR chondrites during stepped combustion. It is possible that this is because Q has become encased within the matrix, in contrast to other carbon phases, during parent body metamorphism.

International audience; A study sponsored by MEPAG has defined the possibilities for cooperative science using two rovers under consideration for launch to Mars in 2018 (ESA’s ExoMars, and a NASA-sourced rover concept for which we use the working name of MAX-C). The group considered collaborative science opportunities both without change to either proposed rover, as well as with some change allowed. Planning focused on analysis of shared and separate objectives, with concurrence on two high priority shared objectives that could form the basis of highly significant collaborative exploration activity. The first shared objective relates to sending the proposed rovers to a site interpreted to contain evidence of past environments with high habitability potential, and with high preservation potential for physical and chemical biosignatures where they would evaluate paleoenvironmental conditions, assess the potential for preservation of biotic and/or prebiotic signatures, and search for possible evidence of past life and prebiotic chemistry. The second shared objective relates to the collection, documentation, and suitable packaging of a set of samples by the rovers that would be sufficient to achieve the scientific objectives of a possible future sample return mission. Achieving cooperative science with the two proposed rovers implies certain compromises that might include less time available for pursuing each rover’s independent objectives, implementation of some hardware modifications, and the need to share a landing site that may not be optimized for either rover. Sharing a landing site has multiple implications, including accepting a common latitude restriction, accepting the geological attributes of the common landing site, and creation of a potential telecommunications bottleneck. Moreover, ensuring a safe landing with the sky crane and pallet system envisioned for the mission would likely result in landing terrain engineering requirements more constraining than those for MSL. Additional possible constraints on the distances the rovers could traverse suggest primary science targets should be within the landing ellipse. Hence, hazard avoidance capability might be necessary to allow for consideration of scientifically compelling sites with a mixture of safe and unsafe terrain.

Solid state sintered silicon carbide ceramics are used in aggressive environments as sealings. There exist data concerning corrosion, but there are only few data concerning their electrocorrosion behaviour. Therefore the electrochemical corrosion of solid state sintered silicon carbide (SSiC) ceramics has been studied at room temperature in acidic and alkaline environments by using potentiodynamic polarization measurements, The investigation showed a pronounced electrochemical corrosion in bases and acids. in HCl and HNO3 pseudo-passivity features due to the formation of a thin layer of SiO2 on the surface were observed, whereas in NaOH soluble silicate ions were observed, resulting in more pronounced corrosion. The microstructural observations of initial and corroded samples reveal that the residual carbon found in the microstructure do not dissolve preferentially.