A primary objective of the NASA Mars 2020 Perseverance rover mission is the detection of organic matter on Mars, which may provide key insights  into the past habitability of Mars and the potential presence of past life. Indeed, molecular biosignatures‒organic molecules diagnostic of biological processes‒may provide more direct evidence of biogenicity than other categories of biosignatures for which biological production is only inferred. However, the degradation of the molecules in the harsh Martian environment over time, along with the limitations of the space flight instruments and the possible transformations induced by the measurements themselves, makes it quite challenging to identify the original material and differentiate between biotic and abiotic organic matter.

The Perseverance rover utilizes a specialized suite of instruments to map minerals and organic distributions at a microscopic scale. Notably, the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument, a deep UV (DUV) Raman and fluorescence spectrometer, previously identified Raman features in the Quartier abrasion target on the Jezero crater floor that suggest the presence of aromatic organics within sulfate matrices [1].

This study builds upon previous findings by reporting similar Raman features in the Pilot Mountain target, located on the Jezero fan top. To interpret these signals, we carried out a systematic laboratory investigation and compared these SHERLOC observations with laboratory data from reference organo-sulfate samples to evaluate the possible organic sources for the detected spectroscopic features [2]. Specifically, we prepared organo-sulfate analog samples using a variety of aromatic organic compounds easily detectable by SHERLOC (both abiotic and of potential biotic origin), and characterized them with laboratory DUV Raman and fluorescence spectrometers analogous to SHERLOC, i.e. the ACRONM instrument located at NASA’s Johnson Space Center, the Brassboard instrument located at the Jet Propulsion Laboratory, and the Photon Systems RPL200 instrument located at INAF-Astrophysical Observatory of Arcetri, operated to mimic SHERLOC analysis.

Comparison between our laboratory dataset and SHERLOC observations for Quartier and Pilot Mountain shows that different types of aromatic organics in sulfates tested in this work‒naphthalene, 1- and 2-naphthol (HN), 1,3- and 2,6-dihydroxynaphthalene (DHN), 9-methylanthracene (9-MA), uracil and an oxy-PAH polymer synthesized from 1-HN (poly1-HN)‒exhibit intense C-C and C=C ring stretching bands (and C=O stretching bands in the case of compounds like uracil with carbonyl functional groups on the aromatic ring) at a variety of positions within the spectral regions of interest, though none of the tested organo-sulfate analogs exhibit fluorescence resembling the co-located fluorescence doublet at ~303 and 325 nm observed in Quartier and Pilot Mountain  (Fig. 1). However, the polycyclic aromatic hydrocarbons (PAHs) 9-MA, 2,6-DHN and 1,3-DHN in magnesium sulfate fluoresce mostly outside the SHERLOC region, which may be consistent with an inorganic origin of the co-located fluorescence doublet, such as luminescence of Ce³⁺ in anhydrite [1,3], illustrating that similar types of three/two-ring aromatic organic molecules could be present.

Fig. 1. Cross-comparison of the features of interest in Quartier and Pilot Mountain with spectra of organo-sulfate analogs for Raman (a) and fluorescence (b).

The association with igneous lithologies suggests that PAHs formed endogenously by igneous processes (Fig. 2). Their location in pores of the igneous rocks may be consistent with Fischer-Tropsch-like synthesis from trapped magmatic gases catalyzed by iron oxides. PAHs might have been subsequently preserved by sulfates precipitated in the pores of the igneous rocks as consequence of their aqueous alteration. Such salt-mediated preservation is particularly efficient on Earth, since sulfate minerals can trap organics within intracrystalline inclusions [4], and exhibit photoprotective properties [5,6].

Regional hydrothermal groundwaters associated with Syrtis Major volcanism might also have played a role in sulfate formation and PAH transportation, as well as in dissolving igneous rocks causing mobilization of Ce³⁺ and its transportation through fractures and precipitation as sulfate veins, which would explain the co-presence of Ce³⁺ and PAHs in these sulfates (Fig. 2).

The organo-sulfate association is consistent with studies on Martian meteorites [7] and observations from Gale crater [8] and reinforces the hypothesis that sulfates might have been key in the preservation and transport of organic molecules in the Martian environment and, hence, could have played a significant role in the Martian carbon cycle, influencing the availability and cycling of carbon compounds necessary for life.

Although we have not found evidence of biogenicity, we cannot exclude that the organics detected in these rocks might be resistant alteration products from the chemical weathering of ancient biotic compounds, and/or a correlation with the organic carbon of potential biotic origin detected in the Bright Angel formation [9]. With the limitations of Perseverance’s Raman and fluorescence spectroscopy techniques, addressing these various hypotheses would require further laboratory studies to retrace the chemical weathering processes that might have occurred at Jezero crater over time leading to the formation of the observed organics, and returning these samples to Earth for high sensitive analysis in Earth-based laboratories.

Fig. 2. Potential mechanisms for the presence of PAHs in sulfates in Quartier and Pilot Mountain.

Acknowledgments: This research was supported by the Italian Space Agency (ASI) through the ASI/INAF agreement no. 2025-12-HH.0, and by INAF Large Grant 2024.

References: [1] Sharma S. et al. (2023) Nature, 619, 724–732. [2] Fornaro T. et al. (2025) Nature Astronomy, 9, 1648–1661. [3] Haney N. C. et al. (2026) JGR-Planets, 131(3), e2025JE009385. [4] Sephton M. A. et al. (2023) J Geol Soc London, 180. [5] Alberini, A. et al. (2024) Scientific Reports, 14, 15945. [6] Alberini A. et al. (2025) Scientific Reports, 15(1), 40484. [7] Jaramillo E. A. et al. (2019)  Geophys Res Lett, 46, 3090–3098. [8] Eigenbrode J. L. et al. (2018) Science, 360, 1096–1101. [9] Hurowitz, J. A. et al. (2025) Nature, 645(8080), 332–340.

How to cite: Fornaro, T. and the Organo-Sulfate Analog Study Working Group: Aromatic Organic Compounds Associated with Sulfates at Jezero Crater: Insights from SHERLOC and Laboratory Analogs, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-194, https://doi.org/10.5194/epsc2026-194, 2026.

Introduction

Mars is one of the primary targets of astrobiological exploration, due to the presence of liquid water on its surface during its early stages and the existence of sedimentary environments that may have hosted and preserved biosignatures [1]. One of the main aims of the current and future missions, including NASA Mars 2020 Perseverance and ESA ExoMars Rosalind Franklin rovers, is to detect such biosignatures using advanced spectroscopic instruments operating across multiple spatial scales [2][3]. To fully exploit these datasets, it is essential to establish a robust interpretive framework based on the characterization of analogous terrestrial samples and Martian meteorites. Within this framework, terrestrial analog environments, such as Proterozoic clay-rich mudstones from the ~1 Ga El Mreiti Group (Mauritania), allow for the study of well-preserved biosignatures formed under sedimentary and diagenetic conditions comparable to those hypothesized for early Mars [4]. At the same time, Martian meteorites offer direct evidence of Martian geochemical evolution and the alteration of organic matter, albeit modified by secondary processes such as thermal and shock alteration during ejection from Mars and entry in Earth Atmosphere [5]. The combined study of terrestrial analogs and Martian meteorites is therefore essential for defining the pathways of biosignature preservation and assessing their detectability in Martian contexts. Another key aspect is the use of techniques that closely mimic those employed in current and future Mars missions. By applying spectroscopic methods relevant to these missions to complex natural samples, it becomes possible to assess detection limits, spectral ambiguities, and the influence of mineral matrices on the expression of biosignatures, thereby providing direct support for the interpretation of in situ data.

Methods

A multi-scale spectroscopic approach was implemented using techniques analog to those deployed on Mars 2020 and ExoMars rovers. Bulk mineralogical and compositional information was obtained through Fourier Transform Infrared (FTIR) spectroscopy in reflectance mode, enabling the identification of dominant mineral phases and broad organic functional groups. Micro-scale heterogeneity was investigated using a Hyperion 1000 micro-FTIR system, allowing the spatial mapping of mineral–organic associations. Visible and Deep Ultraviolet (DUV) Raman spectroscopy and fluorescence analyses were employed to probe the molecular structure and distribution of organic compounds, in a mineral matrix, with particular sensitivity to aromatic and conjugated systems such as kerogens and macromolecular carbons (MMC). This integrated methodology enables a systematic evaluation of biosignature detectability across analog and extraterrestrial materials.

Results

The results presented in this study provide a framework for understanding the spectroscopic expression of biosignatures in complex natural materials. Indeed, the investigation of terrestrial analog samples and Martian meteorites yields key insights into how biosignatures may be preserved, modified, and detected under realistic geological conditions. In particular, this work highlights the importance of multi-scale characterization in resolving mineral–organic associations, demonstrating how biosignatures may manifest differently depending on spatial resolution and analytical technique. The datasets contribute to defining practical detection limits for mission-relevant instruments, suggesting which spectroscopic approaches are best suited for identifying specific classes of organic compounds and their mineralogical context. Furthermore, the results provide constraints on the expected spectral signatures of biosignatures in Martian environments, offering guidance on how such signals may appear – or be obscured – within natural, heterogeneous matrices. Overall, this study establishes a foundation for both current and future analyses of Martian datasets, contributing to the development of more robust biosignature detection strategies and improving the reliability of interpretations derived from in situ and returned sample investigations.

References: [1] Vago J.L. et al. (2017), Astrobiology 17, 471–510; [2] Farley K.A. et al. (2020), Space Sci Rev 216, 142; [3] Vago J. et al. (2015), Solar System Research 49, 518–528; [4] Beghin J. et al. (2017), Precambrian Research 299, 1–14; [5] Steele A. et al. (2016), Meteorit Planet Sci 51, 2203–2225.

Acknowledgements: This research is supported by the Italian Space Agency (ASI) through the ASI/INAF agreement no. 2025-12-HH.0 and PAMMAT project “Alteration processes in Mars and Moon meteorites, and Terrestrial Analogues at different environments: Mars2020, Rosalind Franklin and Returned Samples from Mars and Moon” (Grant No. PID2022-142750OB-I00), funded by the Spanish Agency for Research MCIN/AEI/10.13039/501100011033/FEDER-UE.

How to cite: Alberini, A., Fornaro, T., García Florentino, C., Poggiali, G., Biancalani, S., Renzi, F., Coloma, L., Battistuzzi, M., Roussel, A., Aramendia, J., Madariaga, J. M., and Brucato, J. R.: Supporting the Search for Organics on Mars Through Mission-Analog Spectroscopic Characterization of Terrestrial Analogs and Martian Meteorites, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-905, https://doi.org/10.5194/epsc2026-905, 2026.

Future Mars Sample Return missions will provide extremely limited quantities of rock and soil, posing challenges for conventional geotechnical testing, which typically requires larger specimen masses (e.g., 100s to 1000s of grams). Depending on the return material type, a single sample may contain only ~10 g of loose or regolith-like material. This study investigates how reduced specimen mass affects the results of common geotechnical index tests using the Mars regolith simulant MGS-1, focusing on water content, particle density, particle-size distribution (PSD), and loose/tapped bulk density. Reference values were first established using standard specimen masses (typically ~100 g or ASTM-recommended quantities). Tests were then repeated while systematically reducing the mass (10 g, 2 g, and 0.5 g) to evaluate sensitivity to specimen size. Results demonstrate that sensitivity to reduced mass is strongly method-dependent. At 10 g, most tests (water content, particle density, wet-prepared sieving, and bulk density) remained consistent with reference values and showed low variability. At 2 g, deviations and uncertainty increased, although some methods still followed expected trends. At 0.5 g, results were largely dominated by handling effects and measurement limitations. Dry sieving underestimated fines content compared to wet-prepared sieving and is not recommended as a stand-alone method. Hydrometer testing was identified as the main limitation for full PSD characterization, requiring larger masses for reliable results.

Overall, 10 g represents the lowest broadly reliable specimen mass for MGS-1 across most index tests, with limitations for fine-fraction PSD. While smaller masses may still yield useful data, confidence becomes increasingly method-dependent. The study demonstrates that meaningful geotechnical characterization is feasible with Mars Sample Return-scale materials, provided that deviations from standard methods and associated uncertainties are clearly documented.

How to cite: Setvik, S. H., Quinteros, S., Kim, T., Skurtveit, E., Mikesell, T. D., and Griffiths, L.: Specimen-mass sensitivity in geotechnical index testing of expexted Martian samples, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-1086, https://doi.org/10.5194/epsc2026-1086, 2026.

The physical properties of the surfaces of small Solar System bodies, including particle grain size, porosity, and roughness, are essential for understanding their geological processes and formation history. While reflectance measurements taken at varying wavelengths and geometries can be used to derive these properties through photometry, deriving it remains a challenge due to limitations in the existing photometric models [1]. Therefore, characterizing the photometric behavior of representative surfaces through controlled laboratory experiments can provide valuable constraints for interpreting remote sensing observations. In preparation for Martian Moon eXploration (MMX) mission to Phobos, multiple Phobos simulants have been prepared, and different properties have been characterized in laboratory [2,3].  We have systematically investigated the effects of varying particle size and porosity on the photometric and phase reddening properties of the University of Tokyo Phobos Simulant (UTPS) [2].  

The measurements were conducted using the PHIRE-2 (PHysikalisches Institut Radiometric Experiment - 2) radio-goniometer at the University of Bern [4]. We have found systematic variation in the albedo, opposition effect, and the forward scattering behavior of the sample with the particle size and porosity.  Furthermore, we derived the Hapke parameters [5] for a comparative study against meteorite samples, finding that the phase function of our samples resembles the Allende and Tagish Lake meteorites [6].  The phase reddening behavior of the sample was found to depend strongly on both the particle size and porosity, with finer particles and higher porosity showing higher phase reddening coefficient. Comparing it to the observations from TGO/CaSSIS [7], we found the phase reddening coefficient to be consistent with the values associated with Phobos’s red unit. 

While missions such as Mars Express [8] and TGO [7] continue to observe Phobos, the upcoming Martian Moon eXploration (MMX) mission will provide us with even higher resolution data with more complete coverage. Our work can help in better interpreting spectral and photometric remote sensing measurements, enabling a more comprehensive understanding of Phobos. 

References: 
1. Shkuratov, Y. et al. (2012), "A critical assessment of the Hapke photometric model", Journal of Quantitative Spectroscopy and Radiative Transfer, v113, pp. 2431–2456, doi: 10.1016/j.jqsrt.2012.04.010 

2. Miyamoto, H. et. al. (2021), "Surface environment of Phobos and Phobos simulant UTPS", Earth Planets Space 73, 214, doi: 10.1186/s40623-021-01406-3 

3. Wargnier, A. et al. (2024), "Spectro-photometry of Phobos simulants: I. Detectability of hydrated minerals and organic bands", Icarus v241, 116216, doi: 10.1016/j.icarus.2024.116216 

4. Pommerol, A. et al. (2011), "Photometry and bulk physical properties of Solar System surfaces icy analogs: The Planetary Ice Laboratory at University of Bern", Planetary and Space Science, v59, pp. 1601–1612, doi: 10.1016/j.pss.2011.07.009 

5. Hapke, B. (2012), Theory of Reflectance and Emittance Spectroscopy, 2nd ed., Cambridge University Press, Cambridge. 

6. Beck, P. et al. (2012), "Photometry of meteorites", Icarus, v218, pp. 364–377, doi: 10.1016/j.icarus.2011.12.006 

7. Munaretto, G. et al. (2025), "Phase reddening of Phobos and Deimos from TGO/CaSSIS observations", Astronomy & Astrophysics, doi: 10.1051/0004-6361/202555720 

8. Fornasier, S. et al. (2024), "Phobos photometric properties from Mars Express HRSC observations", A&A, 686, A203, doi: 10.1051/0004-6361/202449220 

How to cite: Keshav, N., Pommerol, A., Schröder, S. E., and Hagermann, A.: Photometric and Phase Reddening properties of a Phobos simulant, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-228, https://doi.org/10.5194/epsc2026-228, 2026.

JAXA's Martian Moon eXploration (MMX) sample return mission aims to solve the long-debated origin of Martian moons Phobos and Deimos [1]. This will be the first attempt to sample an object that either formed in the outer solar system and implanted [2,3,4] into the terrestrial planet region by a major dynamical process (the first origin scenario); or formed from a large impact and subsequently accumulated material from two, very possibly compositionally different, bodies, i.e. Mars and the impactor (the second scenario). In either scenario, impact processes by asteroids, meteoroids, as well as Martian ejecta have altered the surfaces of the Martian moons and require investigation into several aspects such as the crater formation and exposure of fresh sub-surface material, the comminution of surface boulders and regolith production, and the delivery of exogenous materials. 

To provide a frame for the MMX data interpretation, a laboratory experimental campaign is conducted simulating the impact processes on Phobos. We used porous (50%) Phobos simulant materials obtained from the Exolith Lab. These were the PGI-1 and PCA-1 simulating the giant impact and captured asteroid scenarios and we studied the crater depth and diameter as well as the ejecta production as a function of speed and projectile mass. 

In addition we simulated the Martian material contamination on Phobos surface. For this we performed impact experiments using olivine projectiles. Contamination was visible with naked eye and verified using RAMAN spectrometry. 

Furthermore, we produced mixtures of Phobos and Martian simulant and recorded their NIR-FTIR spectra as a function of martian contamination and grain size of the sample. Measurements of simulant mixtures have shown variations in position and band depths of spectral features relative to the volume of Martian material present, in particular the Christiansen feature and 3-micron feature which will be observed by MMX’s miniRAD and MIRS instruments and play a critical role in identifying Martian material on Phobos’ surface. 

Acknowledgements: We acknowledge CNES and STFC funding for initiating this work. 

References:

[1] Usui et al. Space Science Reviews 216, Issue 4, article id.49 (2020). 

[2] Levison et al. Nature 460, Issue 7253, pp. 364-366 (2009). 

[3] Vokrouhlicky, Bottke, Nesvorny. The Astronomical Journal 152, Issue 2, article id. 39, 20 pp. (2016).

[4] Kegerreis et al. Icarus, Volume 425, id.116337 (2025).

How to cite: Avdellidou, C., Branagan-Harris, E., Spathis, V., Burchell, M., Finch, E., Tandy, J., Russell, S., Wozniakiewicz, P., and Alesbrook, L.: Support to MMX mission: Impact cratering and exogenous material contamination on Phobos simulants , Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-1147, https://doi.org/10.5194/epsc2026-1147, 2026.

The JAXA Martian Moons eXploration (MMX) mission will address the question of the origin of Phobos and Deimos by launching a spacecraft to the Mars system in 2026, performing dedicated surveys of the moons, and by collecting a sample from the surface of Phobos and returning it to Earth in 2031 [1]. OROCHI is a wide-angle visible-to-near-infrared (VNIR) 8-channel 8-camera multispectral imaging system for MMX, with a key objective of characterising the surface spectral diversity of the moons from orbit, during descent, and once landed on the surface of Phobos [2]. In the landed configuration OROCHI will reside 80 cm above the Phobos surface, such that the lateral displacements (of 10 cm) between the channel optical axes result in each spectral channel observing the surface with a distinct phase angle.

Here we investigate the implications of this novel multiview-multispectral observation scenario on the recovery of Phobos-like surface spectral reflectance features by imaging pristine grains of asteroids Ryugu and Bennu, collected in aggregate and hosted at the JAXA Extraterrestrial Sample Curation Centre (Ryugu sample “C9003” and Bennu sample “ORX-19000”), with a laboratory simulator of OROCHI [3]. Complementing visible (450 – 750 nm) hyperspectral imaging studies of the phase-dependence of Bennu and Ryugu spectral slope features [4, 5], here we report on observations of the phase-dependence over the OROCHI band profiles (390, 480, 550, 650, 730, 860 & 950 nm).

Remote sensing observations of Ryugu and Bennu show that these bodies each exhibit phase-dependent spectral features (phase reddening), with macroscopic surface roughness and microscopic multiple scattering both as candidate causes, with varying contributions across spatial scales [7, 8]. Phobos also exhibits phase-reddening, to various degrees across the surface, with sub-micron roughness hypothesized as the dominant cause [9]. By measuring the phase-dependence of Ryugu and Bennu spectral features at the sub-mm to mm spatial resolution and over the specific phase angles of OROCHI imaging (when landed), and comparing these near-field (<1 m) observations to remote (>5 km) spacecraft observations, we can prepare to interpret, and photometrically correct for, the phase angle dependence of the Phobos regolith spectral reflectance across the MMX sample area. This will also help prepare for the linking of remote sensing observations from the MMX spacecraft with the laboratory measurements of the Phobos samples that MMX will return to Earth in the 2030’s [9].

[1] Kuramoto et al, 2022, EPS, doi:10.1186/s40623-021-01545-7; [2] Kameda et al, 2021, EPS, doi: 10.1186/s40623-021-01462-9; [3] Stabbins & Kameda, 2026, PEPS, doi: 10.1186/s40645-025-00783-7; [4] Hirota et al, 2026, JpGU-AGU 2026; [5] Hirota et al, 2026, AOGS2026; [6] Golish et al, 2021, Icarus, doi: 10.1016/j.icarus.2020.113724; [7] Tatsumi et al, 2020, A&A, doi:10.1051/0004-6361/201937096; [9] Munaretto et al, 2025, A&A, doi:10.1051/0004-6361/202555720; [9] Tahara et al, 2025, MAPS, doi:10.1111/maps.70066;

How to cite: Stabbins, R., Hirota, S., Yumoto, K., Hatakeda, K., Ryohta, F., and Kameda, S.: Toward Landed Multiview-Multispectral Sensing from the Martian Moons eXploration Spacecraft: Imaging Ryugu & Bennu Samples with the Laboratory OROCHI Simulator, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-1067, https://doi.org/10.5194/epsc2026-1067, 2026.

The Subsurface Radar Sounder (SRS) onboard the European Space Agency’s EnVision mission will investigate the shallow subsurface of Venus using low-frequency radar signals operating at a central frequency of 9 MHz with a bandwidth of 5 MHz. Venus is characterized by widespread volcanic terrains and extremely high surface temperatures, reaching up to ~500 °C. The performance and interpretation of radar signals strongly depend on prior knowledge of the dielectric properties of surface and subsurface materials, which remain poorly constrained under Venus-like conditions. This gap can be addressed through laboratory measurements of terrestrial analogue rocks.

Terrestrial analogue materials were selected based on surface compositions measured by the Venera 13, Venera 14, and Vega 2 landers (Surkov et al., 1984). Representative lithologies of the Venusian crust include basalt, basaltic trachyandesite, and rhyolite.Samples were prepared as polished slabs (~10 × 10 cm). Reflection coefficients were measured using a laboratory setup specifically developed for high-temperature experiments (Baniamerian et al., 2025). Measurements were conducted using an Agilent E5071C vector network analyzer (VNA) over the 1–100 MHz frequency range, employing a logarithmic sweep with 1601 frequency points. A Rohde & Schwarz VNA was also used over the same frequency range with 10,000 frequency points. Prior to measurements, calibration was performed to remove the effects of cables, connectors, adapters, and systematic VNA errors.

For high-temperature experiments, samples were placed inside an insulated Nabertherm furnace, designed to ensure uniform heating from all sides. Measurements were collected at temperatures between ~30 °C and 700 °C, in increments of 100 °C. Calibration was conducted using open, short, and load standards.

These measurements provide key constraints for electromagnetic wave propagation models and support the interpretation of future EnVision SRS observations. As an example, for a basaltic trachyandesite analogue, Figure 1 presents the real part of the complex relative permittivity (ε′ᵣ) and the loss tangent (tan δ) as functions of frequency at various temperatures. The results demonstrate a strong temperature dependence of dielectric properties: both ε′ᵣ and tan δ increase significantly with temperature, particularly at low frequencies, with no evidence of a relaxation mechanism across the measured frequency range.

The complex dielectric permittivity is defined as

The temperature dependence following an Arrhenius-type relation can be formulated as (Parkhomenko, 1967; Jonscher, 1981)

where  and  are coefficients, here E is activation energy in eV,  eV/K is Boltzmann's constant, and T is absolute temperature in Kelvin. This formulation enables modeling of dielectric properties under Venusian thermal conditions.

Figure 2 shows the dielectric properties of basaltic trachyandesite and rhyolite analogues at the SRS operating frequency (9 MHz). The loss tangent increases by up to an order of magnitude across the investigated temperature range. This behavior follows an Arrhenius-type relationship, allowing estimation of activation energies for different lithologies. The results indicate a strong increase in attenuation with temperature, which reduces radar signal penetration depth under Venus surface conditions.

Figure 1. Dielectric properties of Venusian analogues as a function of temperature and frequency: (top) real permittivity and (bottom) loss tangent.

Figure 2. Dielectric properties of basaltic trachyandesite analogues as a function of temperature at 9 MHz: (left) real permittivity and (right) loss tangent.

Acknowledgements

This work was supported by the Italian Space Agency (ASI) under the agreements Accordo Attuativo ASI–UNITrento/DISI n. 2022-23-HH.0 and Addenda n. 2022-23-HH.1-2023 and n. 2022-23-HH.2-2025, for the project “Attività scientifiche per il radar sounder di EnVision Fase B2/C.

References

• Jamaledin Baniamerian, Sebastian E Lauro, Barbara Cosciotti, Alessandro Brin, Carlo Lefevre, Elisabetta Mattei, and Elena Pettinelli. A new experimental setup for high-temperature dielectric characterization of Venus analogs. Journal of Geophysical Research: Planets, 130(7): e2024JE008545, 2025.
• I. Parkhomenko. Electrical Properties of Rocks. Springer, 1967. doi: 10.1007/978-1-4615-8609-8.
• K. Jonscher. The ’universal’ dielectric response. Nature, 267:673–679, 1977. doi: 10.1038/267673a0.
• Yu A Surkov, VL Barsukov, LP Moskalyeva, VP Kharyukova, and AL Kemurdzhian. New data on the composition, structure, and properties of venus rock obtained by venera 13 and venera 14. Journal of Geophysical Research: Solid Earth, 89(S02):B393–B402, 1984.

How to cite: Baniamerian, J., Emanuel Lauro, S., Rabiee, A., Cosciotti, B., Pettinelli, E., Marinangeli, L., Baliva, A., and Mattei, E.: High-Temperature Dielectric Characterization of Venusian Crust Analogues for Subsurface Radar Sounding, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-69, https://doi.org/10.5194/epsc2026-69, 2026.

Introduction: The Chang’E-5 lunar mission collected samples in the north-eastern region of Oceanus Procellarum in December 2020 (Li et al., 2022; Zhou et al.,2022). Two lunar samples from Chang’E5 mission (hereafter CE5-FR) were donated to France. These samples are curated at the Muséum National d’Histoire Naturelle (MNHN) in Paris to conduct non-destructive characterization. These analyses will provide reference data before their allocation to the French scientific community under the supervision of CNES. We will describe the general workflow and results obtained by the analysis of the container gas composition and by a non-invasive and non-destructive characterisation of individual particles extracted from both samples.

Samples and methods: The CE5-FR samples arrived in France stored in glass vials within two aluminium containers. The first sample was ~1 gram of surface-scooped sample (CE5C0100) and the second ~0.5 gram of drilled sample (CE5Z0800). Upon reception the samples were stored under ultra-dry and ultra-pure nitrogen (<1 ppm O₂, <1 ppm H₂O). X-ray Computed Tomography (XCT) allowed to perform 3D images of containers' inside components and to identify the samples' general features, which include tens of large grains (> 100 µm) and grains with higher density and heterogeneities (probably agglutinates).

Gas analysis: We developed a dedicated gas extraction apparatus to recover the containers' gas in the CE5-FR dedicated glovebox. The containers’ base was punctured and the extracted gas transferred into bottles cleaned under high vacuum. The operation was repeated for both CE5-FR drilled and scooped containers. The concentrations of H₂O, O₂, CO₂, CO, and CH₄ were quantitatively determined at LIPhy laboratory using a custom-built direct absorption laser spectrometer (H₂O) and two ultra-sensitive cavity ring-down spectrometers (O₂, CO₂, CO, CH₄) (Chaillot 2023). The argon concentration and isotopic compositions were measured at IPGP on a Noblesse HR 3F6M noble gas mass spectrometer. The results indicate that large amounts of O₂ (~20.2%, ~13.9 %), CO₂ (~840 ppm, ~640 ppm) and argon (>0.7%, >0.01%) were present in the containers for scooped and drilled sample, respectively, with values suggesting significant abundance of terrestrial atmospheric gases.

Bulk sample and individual particles analysis: The global sample mass was measured in the glove box using a Sartorius TE64 balance, and the magnetic susceptibility was measured, in collaboration with the CEREGE team, with a SM150L instrument in a magnetic field of 80 A/m and a variable frequency from from 63 Hz to 16 kHz.

During the gas extraction procedure, a small fraction of the grains escaped from the vials and was recovered on the surface of the Teflon support within each container. We extracted hundreds of grains in a cleanroom environment at IJCLab, and performed characterisation of these particles using complementary non-invasive techniques. Grains with sizes ranging from ~50 to 300 µm were individually documented using a Keyence VHX-7000 digital optical microscope, revealing a large variety of colors, transparency (from opaque to transparent), and morphologies, including smooth crystals, rough surfaces, inclusions, and spherical beads.

Fourier Transform micro-Infrared characterisation (FTIR) of these individual particles was performed with the I2SES bench at IAS. FTIR spectra were measured in reflection mode with respect to gold standards, using a Bruker LUMOS II micro-spectrometer in the mid-infrared: 2.5- 15 µm (4,000-670 cm^-1) with a typical 50 x 50 µm spot size and spectral resolution of 4 cm^-1. A subset of particles was analysed using a Renishaw InVia Raman microspectrometer using a 532 nm laser. High-resolution XRD was performed at IMPMC using a Bruker D8 diffractometer equipped with a double set of Mo/Ag anodes and focussing optics, a large C28 Photon 3 CMOS detector and a unique motorized goniometer allowing microXRD mapping experiment with a ~100µm beam size at the sample position.

A fraction of the scooped sample (~90 mg) and one millimetre-sized grain were extracted in the CE5-FR glovebox and analysed at IAS for microscopic hyperspectral near-infrared (NIR) spectroscopic analysis by PTAL/MicrOmega under controlled atmosphere (Loizeau et al. 2021). A similar analysis will be performed on the drilled sample and the detailed results will be presented in another contribution (see T. Jiang et al. this conference).

Some particles with smaller sizes were identified on the metallic support used for vial manipulation of drilled sample in the glove box. We recovered these particles with conductive carbon tape and they were carbon coated for analysis by scanning electron microscopy (SEM) and later transmission electron microscope (TEM) investigations. The SEM images were performed using SEM-TESCAN instrument at MNHN, allowing to obtain secondary electrons (SE) and back-scattering electrons (BSE) images together with semi-quantitative analysis of major elements by X-ray energy dispersive spectroscopy (EDS).

Further analysis and sample preparation will be performed using a micromanipulator in a dedicated cleanroom at IPGP. A sub-fraction of the sample will undergo gamma-ray spectrometry at the CEA/LNHB to produce additional data to aid the interpretation of radon measurements made by Chang’E-6/DORN (Chacartegui Rojo et al. 2025, Meslin et al. 2025).

The overall dataset of individual particles and bulk batches will be assembled in a database that will be made available under CNES supervision. 

Acknowledgments:

We thank CNSA and the Chang’E-5 mission project for the gift of these lunar samples. This work was supported by DIM ACAV+ (Région Ile de France, C3E project), CNES (APR CE5-CURE), the MARCUS project (ANR-22-EXOR-0010, PEPR Origins). The I2SES bench was funded by DIM-Origins (I2SES project, PI. R. Brunetto), by MNHN, and ANR project LARCAS (grant ANR-22-CE49-0009). The work used the MNHN AST-RX platform for XCT analyses, TESCAN SEM microscope, and the MYRTHO cleanroom at IJCLab (supported by CNES). G.A was supported by the European Research Council (grant agreement n°101041122, project ATTRACTE). S.K. and H.F. thank the REFIMEVE network supported by ANR-11 EQPX-0039 and ANR-21-ESRE-0029.

References:

Li et al. 2022, National science review nwab188. Zhou et al. 2022, Advances in Space Research 823-836. Loizeau et al. 2020 PSS 193, 105087. Chacartegui Rojo et al. 2025, Applied Radiation and Isotopes 226, 112164. Meslin et al. 2025, EGU General Assembly, EGU25-14816. Chaillot, et al. 2025, Chemical Geology 673, 122450.

How to cite: Duprat, J. and Jiang, T. and the CE5-FR team: Curation of Chang’E-5 samples in France : containers opening and individual particle characterization, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-770, https://doi.org/10.5194/epsc2026-770, 2026.

Introduction: China’s Chang’E-5 (CE-5) mission successfully returned ~1.73 kg of lunar samples from the northeastern region of Oceanus Procellarum in 2020 (Li et al., 2022; Zhou et al., 2022). These mare basalts (Morota et al., 2011; Qian et al., 2021; Che et al., 2021) originate from higher latitude than those explored by NASA’s Apollo and the USSR’s Luna missions, offering a unique opportunity to study previously unexamined lunar materials. As a state gift, France received 1.0 g of surface-scooped (CE5C0100) and 0.5 g of drilled material (CE5Z0800). Currently stored at the Muséum National d’Histoire Naturelle (MNHN) in Paris in a dedicated glovebox under ultra-pure nitrogen (<1 ppm O₂ and H₂O), a curation program was initiated by CNES to conduct non-invasive and non-destructive preliminary characterization of the samples before their allocation to the French scientific community.

Samples and methods: A ~90 mg powder (sub-bulk hereafter) and one millimeter-sized grain from the scooped sample were extracted into a sapphire dish within a Faculty-to-Faculty-Transfer-Container (FFTC) (Ito et al., 2020; Yada et al., 2023) inside the glovebox. Then the FFTCs were transported from MNHN to IJCLab for detailed optical imaging of the sample performed with a Keyence VHX-7000 in the MYRTHO cleanroom then transferred to the dedicated glovebox of the MicrOmega instrument installed on the PTAL setup at IAS (Bibring et al. 2017, Loizeau et al. 2021). The hyperspectral MicrOmega microscope covers the near-infrared range (0.99–3.65 µm,) with a spatial resolution of ~20 µm/pixel and a ~5 mm x 5mm field of view. Measurements were conducted in the glovebox under controlled pure-N₂ (with 150-250 ppm H₂O and 40-80 ppm O₂).

Results: Optical imaging shows that the sub-bulk sample consists of fine gray powder (a few to a few tens micron in size) with occasional bright, larger particles.  The average spectrum of the sub-bulk powder at the mm-scale exhibits a red slope typical of the lunar regolith (e.g., Pieters and Nobel 2016), starting from ~8% at 1 µm to ~18% at 2.5 µm. The spectrum also shows the olivine and pyroxene absorption feature (a right shoulder at 1 µm), and shallow absorptions around 1.3 µm, related to olivine and possibly plagioclases, and at 2 µm (pyroxene). These features are consistent with previous studies on other scooped sample from Chang’E-5 mission (e.g., Wu et al., 2024; Jiang et al., 2026). Notably, we observed a clear asymmetrical 3 µm band (centered at ~ 2.83 µm) related to H₂O with a band depth is similar to that of Chang’E-5 scooped sample measured previously under air condition (Jiang et al., 2026). At the sub-mm scale, spectra of the sub-bulk powder reveal olivine (strong 1 µm absorption), high-Ca clinopyroxene (~2.2 µm absorption), and low-Ca orthopyroxene (~1.9 µm absorption) with size varying from a few tens µm to 200-300 µm. The 3 µm absorption related to H₂O also shows some spatial variation. The large mm-sized grain reveals a complex mixture of mineralogical compositions. Detailed statistical analysis of these results will be presented at the conference.

Future plan: Ongoing work includes the analysis of the drilled sample, with similar measurements as for the scooped sample, on a fraction of the bulk powder and on mm-sized grains. We will compare the mineralogy and maturity of the samples between the two sampling sets. Additionally, we recovered small grains, with size between 50 and 300 µm, from the Teflon support during the opening of the containers. We characterized them with both the optical microscope and the FTIR I2SES facilities microscope at IAS (mid-infrared: 2.5-12.5 µm (4,000-800 cm^-1) (Duprat et al. this meeting). The larger grains will be selected for MicrOmega measurements, which will allow to link the NIR and MIR data to provide better reference information for the grain composition.

Acknowledgements:

We thank CNSA and the Chang’E-5 mission project for the gift of these lunar samples, DIM ACAV+ (Région Ile de France, C3E project), CNES (APR CE5-CURE and MicrOmega development and activities), the MARCUS project (ANR-22-EXOR-0010, PEPR Origins) for financial support. The FTIR microscope at IAS was funded by DIM-Origins (I2SES project, PI. R. Brunetto). This work used the MYRTHO clean room at IJCLab, which receives support from CNES.

References:

Bibring, J-P., et al. 2017, Space Science Reviews 208, 401-412. Che, X., et al. 2021 Science 374, 887-890. Ito M. et al., 2020 Earth, Planets and Space 72:133. Jiang T. et al., 2026 A&A 705 A223. Li, C., et al. 2022, National science review nwab188. Li, Q., et al. 2021, Nature 600, 54-58. Loizeau et al. 2020 Planetary and Space Science 193, 105087. Morota, T., et al. 2011, Earth and Planetary Science Letters 302, 255-266. Qian, Y., et al. 2021, Earth and Planetary Science Letters 561, 116855. Wu, Y. Z., et al. 2024 A&A 682, A112. Yada T. et al., 2023 Earth, Planets and Space 75: 170. Zhou, C., et al. 2022, Advances in Space Research 69, 823-836.

How to cite: Jiang, T., Loizeau, D., Poulet, F., Pilorget, C., Brunetto, R., Duprat, J., Engrand, C., Dalauche, L., Bibring, J.-P., Hamm, V., and Lourit, L.: Near-Infrared Hyperspectral Imaging of Chang’E-5 samples in France using MicrOmega: Preliminary Results., Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-647, https://doi.org/10.5194/epsc2026-647, 2026.

Several approaches are currently available for investigating the composition of Mars and the Moon, including in situ analyses performed by rovers and landers, orbital observations, and laboratory investigations of meteorites collected on Earth. In the case of Mars, missions such as the Perseverance rover from the Mars 2020 mission [1] and the future Rosalind Franklin rover from the ExoMars mission [2] provide in situ geochemical and mineralogical analyses, while orbital studies are carried out by spacecraft such as the Mars Reconnaissance Orbiter [3]. Similarly, the Moon is being investigated through surface missions involving rovers such as the Yutu-2 [4], and the Pragyan rovers [5], together with orbital measurements acquired by missions including the Lunar Reconnaissance Orbiter [6]. Complementary information about these planetary bodies can also be obtained through the analysis of Martian and Lunar meteorites recovered on Earth. Their study also helps to better understand the limitations and constraints associated with different analytical techniques when applied to such complex and heterogeneous materials.

Meteorite samples are commonly prepared as polished subsamples suitable for non-destructive spectroscopic analyses. However, different preparation and preservation procedures can be applied, ranging from polished standalone pieces to subsamples embedded in resin blocks for improved mechanical stability and long-term preservation [7]. In this work, Martian and Lunar meteorites (LAR 12011, MIL 090036, MIL 05035 and EET 79001) prepared following these different methodologies were analyzed using micro-Raman spectroscopy, near-infrared (NIR) imaging, and micro-Energy Dispersive X-ray fluorescence (µED-XRF)  in order to evaluate the influence of sample preparation on the measurements obtained with each analytical technique and to study and understand the limitations of these techniques.

Particular attention was given to mapping modalities that allow the acquisition of hyperspectral data cubes. The role of spatial resolution, one of the most critical parameters in the spectroscopic characterization of heterogeneous planetary materials, was investigated. In fact, depending on the selected spatial resolution, the analyses may either provide information representative of the bulk matrix composition or enable the identification of minor mineral phases and mesostasis components present in lower abundances within the meteorites. To gain a clearer understanding of how spatial resolution affects each analytical technique additional experiments were conducted on a reference matrix of a terrestrial igneous analogue with chemical alterations with a similar composition than the studied meteorites. An example of Raman images obtained with different spatial resolution can be seen in Figure 1.

Figure 1. Raman images in the terrestrial analogue with different spatial resolution parameters. The central image was obtained using a step size of 105 µm, whereas the image on the right was acquired with a step size of 600 µm.

The results highlight the importance of optimizing the spatial resolution according to the analytical objective and of combining complementary spectroscopic techniques to achieve a representative and comprehensive characterization of the heterogeneous mineralogical and chemical composition of Martian and Lunar meteorites, as each method provides distinct information on the samples. Guidelines are also provided to help avoid misinterpretation of observed features and ensure consistency between measured signals and actual sample characteristics.

Acknowledgements

Meteorites were provided by the US Antarctic Meteorite Program, through the loan agreement between NASA’s JSC and the UPV/EHU. This work has been supported through the PAMMAT project “Alteration processes in Mars and Moon meteorites, and Terrestrial Analogues at different environments: Mars2020, Rosalind Franklin and Returned Samples from Mars and Moon” (Grant No. PID2022-142750OB-I00), funded by the Spanish Agency for Research MCIN/AEI/10.13039/501100011033/FEDER-UE, and the Strategic Project “Study of Alteration Processes in Terrestrial and Planetary Materials” (Grant No. UPV/EHU PES 21/88).

References

[1] T. Fouchet, J.-M. Reess, et al., The SuperCam infrared spectrometer for the Perseverance rover of the Mars 2020 mission, Icarus 373 (2021) 114773. https://doi.org/10.1016/j.icarus.2021.114773.

[2] J.L. Vago, F. Westall, et al., Habitability on Early Mars and the search for biosignatures with the ExoMars rover, Astrobiology 17 (2017) 6-7. https://doi.org/10.1089/ast.2016.1533.

[3] R.W. Zurek, S.E. Smrekar, An overview of the Mars Reconnaissance Orbiter (MRO) science mission, J. Gephys. Res. Planets 112 (2007). https://doi.org/10.1029/2006JE002701.

[4] C. Li, D. Liu, et al., Chang’E-4 initial spectroscopic identification of lunar far-side mantle-derived materials, Nature 569 (2019) 378-382. https://doi.org/10.1038/s41586-019-1189-0.

[5] S.V. Vadawale, N.P.S. Mithun, et al., Chandrayaan-3 APXS elemental abundance measurements at lunar high latitude, Nature 633 (2024) 327-331. https://doi.org/10.1038/s41586-024-07870-7.

[6] R. Vondrak, J. Keller, G. Chin, J. Garvin, Lunar Reconnaissance Orbiter (LRO): Observations for Lunar Exploration and Science, Space Sci. Rev. 150 (2010) 7-22. https://doi.org/10.1007/s11214-010-9631-5.

[7] R. Harrington, K. Righter, Polished sample preparation without epoxy, 50th Lunar and Planetary Science Conference (2019) 2132.

How to cite: Coloma, L., Gorla, G., Sánchez-Goyenaga, M., Alberquilla, F., Aramendia, J., Arana, G., and Madariaga, J. M.: Challenges in Achieving Representative Multispectroscopic Analyses of Martian and Lunar Meteorites: Effects of Sample Preparation, Heterogeneity, and Spatial and Spectral Resolution, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-1121, https://doi.org/10.5194/epsc2026-1121, 2026.

Volcanic glasses are widespread on the Moon and represent an important component of both pyroclastic deposits and the lunar regolith. These amorphous materials originate from explosive volcanic eruptions as well as from impact-related processes, and therefore preserve valuable information on the evolution of the lunar crust and mantle. Despite their relevance for the interpretation of remote sensing observations, amorphous silicate materials remain significantly underrepresented in current spectral libraries, especially when compared to crystalline phases. In this framework, laboratory investigations on well-characterized analogue materials are essential for improving the identification and interpretation of glass-rich planetary surfaces. In this work, we present a combined Visible-Near Infrared (VNIR, 400-2500 nm) and Mid-Infrared (MIR, 3000-25000 nm) spectral characterization of synthetic silicate glasses representative of lunar mafic to ultramafic compositions.

Four lunar analogue compositions derived from Apollo samples were synthesized in laboratory: a high-Ti mare basalt (MB), a low-Ti basalt (LTB), a KREEP basalt (KB), and an Apollo 15 green glass analogue (GG). The glasses were produced from high-purity oxide mixtures and subsequently separated into four grain size fractions (<38 μm, 38-63 μm, 63-106 μm, and 106-150 μm) to evaluate the influence of particle size on spectral behaviour.

Reflectance spectra were acquired using FTIR (Fourier Transform Infrared) spectroscopy across the VNIR and MIR spectral ranges. Additional XRPD (X-Ray Powder Diffractometry) analyses confirmed the predominantly amorphous nature of the synthesized materials, although the high-Ti MB sample displayed traces of crystallization, likely related to Fe-Ti oxide nucleation during quenching. Spectral analyses focused on the behaviour of albedo, spectral slopes, VNIR absorption bands, and MIR diagnostic features such as the Christiansen Feature (CF), Reststrahlen bands peak position (RB_peak), and Transparency Feature (TF).

In the VNIR domain, all samples display weak and broad absorption features centered near ~1100 nm and ~1900 nm, attributed to Fe²⁺ electronic transitions in octahedral and tetrahedral coordination. Compared to crystalline materials, these absorptions appear toned down and poorly resolved, reflecting the amorphous structure of the studied glasses. Spectral slopes and albedo are strongly affected by grain size, with finer fractions generally showing higher reflectance and steeper VIS slopes. However, significant compositional effects are also observed. In particular, the MB sample shows an anomalous spectral behaviour, characterized by increasing albedo toward coarser fractions and flattened VNIR slopes. The influence of composition was investigated through the SAT parameter (SiO₂+Al₂O₃+TiO₂), the SCFM index, and iron content. Overall, grain size exerts the dominant control on VNIR spectral variability, partially masking compositional trends.

In the MIR region, spectral behaviour is dominated by vibrational processes within the silicate framework and provides clearer compositional constraints. The CF position systematically shifts toward shorter wavelengths with increasing grain size and exhibits a strong correlation with parameters related to silicate network polymerization, particularly SAT and SiO₂ content. The finest grain size fractions (<38 μm) show the best agreement with trends previously reported in the literature for synthetic silicate glasses. In contrast, the RB_peak position displays a weaker and more scattered compositional dependence, although partial correlations with the SCFM parameter can be recognized. A weak TF is observed exclusively in the finest grain size fractions, confirming the strong grain size control on this spectral feature and the generally weak MIR spectral contrast of low-alkali silicate glasses.

In conclusion, the results demonstrate that MIR spectral parameters, particularly the Christiansen Feature, provide more robust compositional constraints than VNIR spectral properties, whereas VNIR data remain useful for identifying iron-rich glassy materials and evaluating grain size effects. The dataset presented here extends current spectral libraries toward primitive lunar mafic compositions and contributes to improving the interpretation of orbital and in situ lunar observations. This work contributes to improving spectral libraries of amorphous planetary materials and supports future investigations of glass-rich volcanic and impact deposits on the Moon and other rocky bodies.

Acknowledgements

We acknowledge the support of ASI under the ASI-UniPg agreement 2019-2-HH.0.

How to cite: Scognamiglio, G., Pisello, A., Fastelli, M., Tiraboschi, C., Zinzi, A., and Perugini, D.: Spectral Characterization of Synthetic Silicate Glasses Analogous to Lunar Basalts, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-1094, https://doi.org/10.5194/epsc2026-1094, 2026.

The supercritical fluid state is reached for certain compounds at high pressure and temperature, above their critical point. Under these conditions, such fluids combine the properties of gases (high diffusivity, low viscosity) and liquids (high density, strong solvating power), making them particularly suitable for the extraction of organic molecules from complex matrices, such as extraterrestrial samples. For instance, meteorites, and especially carbonaceous chondrites, can contain up to 4% organic matter^1,2. Organic compounds such as amino acids, nucleobases, sugars, and carboxylic acids, considered among the “building blocks of life”, have been reported in meteorite sample^3–5. To better understand the role of meteorites in the emergence of life on Earth nearly 4 billion years ago, their molecular characterisation is therefore essential. However, organic matter, already present in low quantities in carbonaceous chondrites, is often strongly bound to the mineral matrix, making its extraction particularly challenging.

Supercritical fluids therefore offer a promising approach to overcome this limitation. The widespread use of supercritical CO₂ (scCO₂), due to its relatively low critical point (74 bar and 31 °C), as well as its availability, non-toxicity, non-flammability, and easy removal upon depressurisation, makes supercritical fluid extraction (SFE) a green chemistry technique⁶. In addition, scCO₂, commonly used for the extraction of non-polar compounds, can be mixed with polar co-solvents such as methanol, ethanol, dichloromethane, acetonitrile, or water to enable the simultaneous extraction of polar compounds. Moreover, recent instrumental developments allow the mixing of co-solvents with scCO₂ upstream of the sample, making it possible to generate co-solvent mixtures, gradients, and extraction sequences without intermediate sample handling, thereby reducing the risk of contamination. These advances over the past decades make SFE a promising alternative to more conventional extraction methods. It often provides comparable or higher recovery yields^7–10, while overcoming common drawbacks such as high temperatures and pressures, multistep protocols, the use of toxic or polluting solvents, and contamination risks.

In the context of astrobiology, SFE is particularly well suited for complex and valuable samples, as it is a semi-destructive technique that preserves the mineral matrix after extraction of soluble compounds, while providing efficient extraction and a low risk of contamination. Although astrobiology emerged in the late 1950s, this technique has only begun to be explored in this field over the past three decades^11–15, especially for sample return or meteoritic samples. In this study, we focus on meteoritic samples by investigating the capabilities of SFE considering recent developments, particularly the possibility of implementing a one-step protocol with successive co-solvent mixtures or gradients within a 2 mL sample cell, a more realistic volume given the limited availability of meteoritic material. To develop our protocol, we first optimise the large number of parameters using a meteoritic analogue. Using methanol as a co-solvent, an initial screening of the system was performed by focusing on the four most influential parameters (pressure, temperature, static extraction time, and methanol/scCO₂ ratio), allowing us to explore the parameter space with only 19 experiments using a full factorial design. Finally, considering that different molecules are extracted under different conditions, we aim to optimise the protocol using co-solvent gradients to develop a single extraction workflow capable of efficiently targeting multiple molecular classes through successive extraction steps. We will present the first results obtained from this optimisation and compare them with classical extraction methods.

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• Burton, A. S., Stern, J. C., Elsila, J. E., Glavin, D. P. & Et., A. Understanding prebiotic chemistry through the analysis of extraterrestrial amino acids and nucleobases in meteorites. Chemical Society Reviews https://doi.org/10.1039/C2CS35109A (2012) doi:10.1039/C2CS35109A.
• Alexander, C. M. O., Cody, G. D., De Gregorio, B. T., Nittler, L. R. & Stroud, R. M. The nature, origin and modification of insoluble organic matter in chondrites, the major source of Earth’s C and N. Geochemistry 77, 227–256 (2017).
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• Sun, L. & Lee, H. K. Optimization of microwave-assisted extraction and supercritical fluid extraction of carbamate pesticides in soil by experimental design methodology. Journal of Chromatography A 1014, 165–177 (2003).
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• Hawthorne, S. B., Grabanski, C. B., Martin, E. & Miller, D. J. Comparisons of Soxhlet extraction, pressurized liquid extraction, supercritical fluid extraction and subcritical water extraction for environmental solids: recovery, selectivity and effects on sample matrix. Journal of Chromatography A 892, 421–433 (2000).
• Spack, L., Alvarez, C., Martins, J. M. F. & Tarradellas, J. Comparison of supercritical fluid extraction (SFE), Soxhlet and shaking methods for pendimethalin extraction from soils: effect of soil properties and water content. Journal of Contaminant Hydrology 33, 171–185 (1998).
• McCaig, H. C. et al. Supercritical Carbon Dioxide Extraction of Coronene in the Presence of Perchlorate for In Situ Chemical Analysis of Martian Regolith. Astrobiology 16, 703–714 (2016).
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• Franco, C. & Hintze, P. Instrument for Solvent Extraction and Analysis (ISEE) of Organics from Regolith Simulant Using Supercritical Fluid Extraction and Chromatography. http://hdl.handle.net/2346/73007 (2017).

How to cite: Bouhier, B., Bourmancé, L., Stalport, F., Cottin, H., and Azémard, C.: Supercritical Fluid Extraction of organic molecules from extraterrestrial samples: A new one-step protocol proposed, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-851, https://doi.org/10.5194/epsc2026-851, 2026.

Understanding the formation and activity of comets is key to constraining the conditions of the early solar system. As a comet approaches the Sun, its surface water-ice undergoes sintering, forming interparticle necks that significantly alter the ice’s physical properties, including its tensile strength. Gundlach et al. (2018) showed that sintering can proceed at temperatures as low as ~160 K. In this work, we systematically investigate how sintering temperature and duration affect the tensile strength of cometary ice analogues and examine the samples under a low-temperature scanning electron microscope (SEM).

Following the methodology of Kreuzig et al. (2024), we produce granular ice disks at 77 K in a newly designed sample holder. These disks are transferred into a liquid-nitrogen-cooled vacuum chamber, where they are heated from 77 K to a target temperature between 160 K and 200 K, held for variable time intervals on the order of hours, and then cooled back to 77 K to preserve the sintered microstructure. Tensile strength is measured in situ at 77 K using the Brazilian Disk Test (BDT), implemented on a custom apparatus adapted by the author from the CoPhyLab cone-penetration setup (Figure 1).

To resolve the microstructural evolution, sintered samples are examined under a low-temperature SEM, quantifying neck sizes as functions of sintering temperature and time (Figure 2). The resulting dataset will clarify the relationship between sintering parameters and tensile strength, thereby improving models of comet surface mechanics.

Figure 1. Photomontage of the planned Brazilian Disk Test (BDT) setup, analogue to the setup used by Kreuzig et al. (2024). A motor drives a stainless-steel blade, mounted to a precision load cell, downward onto the ice-disk sample seated on the sample table. The load cell continuously records the applied force and registers the peak load at sample failure. Blade displacement is tracked by a camera imaging a small reference tab against an LED backlight strip.

Figure 2. SEM picture of granular ice. The ice was kept at 77K at all times, no sintering is expected here and not visible.

How to cite: Quade, M., Kreuzig, C., Knoop, C., Timpe, M., and Blum, J.: Experimental results from CoPhyLab: Influence of Low-Temperature Sintering on the Tensile Strength of Cometary Ice Analogues determined by BDT, Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-450, https://doi.org/10.5194/epsc2026-450, 2026.

DNA is ubiquitous to all life on Earth and is thus considered an indicator for a universal ancestor; however, the origin of this ancestor is debated. Possible origins include endogenous production, for example in the young Earth’s oceans around hydrothermal vents, or exogenous delivery, as a result of impacts early in the Earth’s history [1]. If the former is correct, then Enceladus, with its briny liquid ocean, high geologic activity resulting in hydrothermal vents at the ocean-core boundary, and high abundance of complex organic molecules and fragments, is one of the key astrobiological targets within our Solar System [e.g., 2, 3]. However, its thick icy surface means it is not feasible for us to directly access and sample the ocean [4]; but conveniently, large plumes of ice and vapour are found to erupt from the Enceladean South Polar Region, potentially carrying a whole wealth of knowledge about the subsurface ocean [5]. As a universal feature of biological life on Earth, the detection of DNA in the ocean of Enceladus would provide strong indications of life within.

One of the biggest challenges for sample collection and analysis from the Enceladean plumes is capture speed, and thus peak impact shock pressure, which depend on the orbit type and is expected to range from 250 m/s (Enceladus orbit), up to 6 km/s or more (Saturn orbit/Enceladus flyby) [5]. Careful planning is therefore required to ensure efficient sample capture with minimal disruption or modification to minerals, organics, and biomarkers. Using the Light Gas Gun at the University of Kent, we are investigating the effect of impacts on the structure of DNA using a range of collection mediums, as well as different methods of post-impact recovery and analysis. At low speeds, up to ~ 1 km/s, short DNA ladders up to 1000 bp can survive and be characterised in analysis after impacting a soft metal such as indium. However, at higher speeds the concentration and structure of the DNA is lost. By contrast, DNA impacted onto aluminium is able to withstand speeds up to ~2.5 km/s, although there are potential signs of ladder breakdown. Further work at higher speeds is on-going to provide more definitive breakdown characterisation. Nevertheless, these preliminary results indicate that it would indeed be possible to successfully collect and characterise any small-chain DNA present in the plumes of Enceladus within current mission proposal constraints which include Enceladean orbiters. 

[1] Chyba & Sagan, 1992, Nature; [2] Postberg et al., 2018, Nature; [3] Khawaja et al., 2025, Nature Astronomy; [4] Hemingway & Mittal, 2019, Icarus; [5] Burchell & Wozniakiewicz, 2024, MAPS. 

How to cite: Grant, H., Robinson, G., Tandy, J., Burchell, M., and Wozniakiewicz, P.: Hypervelocity impacts of DNA on soft metals and implication for sample capture and characterisation efficiency , Europlanet Science Congress 2026, The Hague, The Netherlands, 6–11 Sep 2026, EPSC2026-1188, https://doi.org/10.5194/epsc2026-1188, 2026.