BioSigN (BioSignatues and habitable Niches) is a space experiment supported by ESA and foreseen to be performed  in Low Earth Orbit on the exposure lab Exobio on Bartholoméo to be fixed outside the Columbus Module on the International Space Station (ISS). The main objective of BioSigN is to support and prepare future planetary exploration missions to Mars, Enceladus, Europa and/or Titan by conducting exposure experiments on the ISS. To maximize the scientific output, the outcome of BioSigN will be connected to the results obtained on ground from recent and up-coming planetary analogue field site studies and planetary simulation facilities. The BioSigN project is conceived to achieve three central objectives:

• To analyse to what extent selected organisms and (micro-)fossils acquired from Icy Moon/Marsanalogue field sites (terrestrial and ocean/deep sea location) can survive/outlast the conditions of space exposure;
• To evaluate by the obtained results the habitability of present/past Mars and of the icy ocean worlds in the solar system.
• To test the (in)stability of a particular set of bio-molecules when exposed to space and Mars-like conditions, and to investigate their mechanisms of resistance or degradation as well as analysing if they are still detectable by the commonly used life detection methods;

To reach these goals, the test samples will be exposed to space vacuum and space radiation, approaching icy-moon specific or planet-specific gaseous and solar environments. 

How to cite: de Vera, J.-P. P. and Baqué, M. and the BioSigN team: BioSigN: using an exposure lab on the ISS for preparation of in situ life detection missions and habitability studies, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-114, https://doi.org/10.5194/epsc2024-114, 2024.

Asteroids have been recognised as the parent bodies of most meteorites (Wylie, 1939), and, as a result of bombardment by micrometeorites and interplanetary dust particles, are believed to be surrounded by clouds of ejected surface dust particles (Szalay & Horányi, 2016).

It has recently been postulated by Cohen et al. (2019) that the composition of asteroidal ejecta dust clouds may be determined by the interception of cosmic dust grains by an impact ionisation mass spectrometer aboard a spacecraft conducting a flyby mission (c.f. the Cosmic Dust Analyser aboard Cassini, Srama et al. 2004, or more modern instrumentation, such as the Surface Dust Analyser aboard Europa Clipper, Kempf et al. 2014). The geochemical compositions and abundances of different grains contribute a “fingerprint” identity of an asteroid body, from which the meteorite type most closely linked to the asteroid can be determined.

The approach by Cohen et al. (2019) is generally applicable to asteroid flybys at high velocity regimes (approximately greater than 19 km/s), comparable to that of the planned DESTINY+ flyby mission to asteroid 3200 Phaethon. An extension to this technique, applicable to flyby speeds more typical of dedicated missions to the asteroid belt (e.g. 7-10 km/s), was subsequently proposed by Eckart et al. (2023).

To test the efficacy of the proposed theories, we intend to generate and analyse ensembles of cosmic dust analogues from meteorite samples, which, following metal coating, will be electrostatically accelerated onto laboratory engineering models, or flight spares, of impact ionisation mass spectrometers, such as the Destiny Dust Analyser, to be aboard the DESTINY+ spacecraft (Krüger et al. 2019). The obtained mass spectral datasets will then be statistically analysed both individually and as a cohort in order to identify unique features, which can lead towards the linking of the mass spectra to the original meteorite type/class.

Here we present the latest results and progress in obtaining, characterising, and preparing meteorite samples in order to simulate, within the laboratory, expected data from the impact ionisation mass spectrometry of asteroid dust-clouds aboard flyby spacecraft. The curation of a library of mass spectral data from meteorite mineral phases will largely facilitate the identification of unique meteorite samples and the subsequent tracing of these specimens back to their parent asteroids, providing a deeper insight into the evolution of our solar system.

References

Eckart, L. M., Hillier, J. K., Postberg, F., Marchi, S., & Sternovsky, Z. (2023). Linking meteorites to their asteroid parent bodies: The capabilities of dust analyzer instruments during asteroid flybys. Meteoritics & Planetary Science, 58(10), 1449–1468.

Kempf, S., Altobelli, N., Briois, C., Gru€n, E., Horanyi, M., Postberg, F., Schmidt, J., Srama, R., Sternovsky, Z., and Tobie, G. 2014. SUDA: A Dust Mass Spectrometer for Compositional Surface Mapping for a Mission to Europa International Workshop on Instrumentation for Planetary Missions, p. 7.

Krüger, H., Strub, P., Srama, R., Kobayashi, M., Arai, T., Kimura, H., Hirai, T., Moragas-Klostermeyer, G., Altobelli, N., Sterken, V. J., Agarwal, J., Sommer, M., & Grün, E. (2019). Modelling DESTINY+ interplanetary and interstellar dust measurements en route to the active asteroid (3200) Phaethon. Planetary and Space Science, 172, 22–42.

Srama, R., Ahrens, T. J., Altobelli, N., Auer, S., Bradley, J. G., Burton, M., Dikarev, V. V., et al. 2004. The Cassini Cosmic Dust Analyzer. In The Cassini-Huygens Mission: Orbiter In Situ Investigations, edited by C. T. Russell, 2nd ed., 465–518. Dordrecht: Springer.

Szalay, J. R., and Horányi, M. 2016. The Impact Ejecta Environment of near Earth Asteroids. The Astrophysical Journal 830: L29.

Wylie, C. C. 1939. Where Do Meteorites Come from? Science 90: 264–65.

How to cite: Dewey, P., Hillier, J. K., Postberg, F., Eckart, L. M., Srama, R., and Trieloff, M.: Synthesis and Characterisation of Cosmic Dust Analogue Ensembles from Meteorite Samples , Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1056, https://doi.org/10.5194/epsc2024-1056, 2024.

DESTINY+(Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science) is a future JAXA interplanetary space mission to the active asteroid 3200 Phaethon (Ozaki et al. 2022). The primary scientific payload - the Destiny Dust Analyzer (DDA; Simolka et al. 2024), an impact ionisation mass spectrometer - will assess physicochemical properties of (sub-)micron-sized dust particles emitted by Phaethon. Over the mission duration, DDA will also sample dust particles originating from different environments: lunar, interplanetary, and interstellar. DDA is a time of flight (TOF) impact ionisation mass spectrometer - a successor to Cassini’s Cosmic Dust Analyzer (CDA; Srama et al. 2004), which sampled ice and dust from the Saturnian system - and similar to Europa Clipper’s SUrface Dust Analyzer (SUDA; Kempf et al. in review) that will visit the Jovian moon Europa. These instruments utilise impact ionization; nanometere- to micron-sized dust particles strike the instrument’s target at hypervelocities, ionising chemical species embedded within particles and generating a TOF mass spectrum.

Both for calibration of DDA and the generation of a cationic mass spectral library to characterise the composition of dust in space, laboratory experiments are currently underway using DDA’s engineering model. Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous organic compounds in many different space and planetary environments – e.g. they are a major constituent of carbonaceous chondrites. For this reason, we investigate polypyrrole coated perylene PAH particles prepared in the form of microparticles and accelerate them using a Van de Graaff dust accelerator. Here, we present the first analysis of the cationic TOF mass spectra of such particles accelerated at 750 kV and recorded over an impact speeds range of 3-36 km/s. The spectra successfully exhibit mass line corresponding to the molecular ion [M]⁺ of perylene at m/z 252 for impact speeds between 3 and 7 km/s. From impact speeds of 9 to 16 km/s, the spectra exhibit a sequence of consecutive mass lines above m/z 45 with mass resolution ∆m ≈ 12-14, sufficient to characterise a homologous series of cations from PAHs. In addition, these spectra also show low mass fragment cations that most likely arise from the coating material of polypyrrole and from target contamination.

Future work will investigate these particles accelerated over higher potential differences up to 2 MV, as well as the mass spectral appearance of other PAHs. This carries relevance not only for DDA, but also for other impact ionisation mass spectrometers onboard future space missions (e.g., SUDA onboard NASA’s Europa-Clipper) that look to sample interplanetary and interstellar dust.

References

Kempf et al. (2024), SUDA: A SUrface Dust Analyser for compositional mapping of the Galilean moon Europa. Space Science Reviews, in review.

Ozaki N et al. (2022), Mission design of DESTINY +: Toward active asteroid (3200) Phaethon and multiple small bodies. Acta Astronaut. 196 , 42–56.

Srama et al. (2004), The Cassini Cosmic Dust Analyser. Space Sci. Rev., 114, 465–518.

Simolka et al. (2024) The DESTINY+ Dust Analyser — a dust telescope for analysing cosmic dust dynamics and composition. Phil. Trans. R. Soc. A 382: 20230199.

How to cite: Khawaja, N., Srama, R., Chan, D., Armes, S., Yanwei, L., Simolka, J., Strack, H., Mocker, A., Hillier, J., Postberg, F., Trieloff, M., Krüger, H., and Hirai, T.: Calibration of Destiny Dust Analyzer (DDA) with Polypyrrole Coated Perylene Microparticles, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1119, https://doi.org/10.5194/epsc2024-1119, 2024.

The surfaces of icy moons are primarily composed of water ice that can be mixed with other compounds, such as carbon dioxide. With the recent JWST observations (Bockelee-Morvan et al. 2024; Villanueva et al. 2023), infrared spectra of Ganymede and Europa’s terrains have been generated with unprecedented resolution, revealing hitherto undetectable variations of the spectral features with the location on the moon. With such high resolution’s data, not only can we identify the species present (in the present case CO₂) on the surface, but we can also link their subtle variations to the embedding of the molecule into a host material and/or to energetic processes occurring on the icy moon. The carbon dioxide (CO₂) stretching fundamental band observed on Europa and Ganymede appears to be a combination of several bands that are shifting location from one moon to another but also from one terrain to another on the moon itself. We investigated the cause of the observed shift in the CO₂ stretching absorption band experimentally. For this purpose, we explored the spectral behavior of CO₂ ice by varying the temperature and concentration with respect to water, focusing on the CO₂ stretching fundamental band. We analyzed pure CO₂ ice and ice mixtures deposited at 10 K under ultra-high vacuum conditions using Fourier-transform infrared (FTIR) spectroscopy and temperature programmed desorption (TPD) experiments. Laboratory ice spectra were compared to JWST observation of Europa's and Ganymede's leading hemispheres. To confirm the assignment of one of the CO₂ bands, we simulated IR spectra using density functional theory (DFT) methods, exploring the effect of porosity in CO₂ ice. Pure CO₂ and CO₂-water ice show distinct spectral changes and desorption behaviors at different temperatures, revealing intricate CO₂ and H₂O interactions. The number of discernible peaks increases from two in pure CO₂, referred to as  ν3,1 and ν3,2, and to three in CO₂-water mixtures, referred to as ν3,1, ν3,2 and ν3,3.

The different CO₂ bands were assigned to ν3,1 (2351 cm^-1, 4.25 µm) caused by CO₂ dangling bonds (CO₂ found in pores or cracks) and to  ν3,2 (2345 cm^-1, 4.26 µm) due to CO₂ segregated in water ice, whereas  ν3,3 (2341 cm^-1, 4.27 µm) is due to CO₂ molecules embedded in  water ice. The JWST NIRSpec CO₂ spectra for Ganymede and for Europa can be fitted with two Gaussians attributed to ν3,1 and ν3,3. For Europa, as shown in Fig.1, ν3,1 is located at lower wavelengths due to a lower temperature. The Ganymede data reveal latitudinal variations in CO₂ bands, with  ν3,3 dominating in the pole and  ν3,1 prevalent in other regions. This shows that CO₂ is embedded in water ice at the poles, and it is present in pores or cracks in other regions. Ganymede longitudinal spectra reveal an increase of the CO₂   ν3,1 band throughout the day, possibly due to an increase in ice cracks or pores caused by large temperature fluctuations during a day on Ganymede.

References:

Bockelee-Morvan, D., Lellouch, E., Poch, O., et al. 2024, Astronomy & Astrophysics, 681, A27

Villanueva, G., Hammel, H., Milam, S., et al. 2023, Science, 381, 1305

How to cite: Cazaux, S., Schiltz, L., Escribano, B., Muñoz Caro, G., del Burgo Olivares, C., Carrascosa, H., González Díaz, C., Chen, A., Giuliano, M., Caselli, P., and Boshuizen, I.: Characterization of Carbon Dioxide (CO2) on Ganymede and Europa supported by experiments: The effect of temperature, porosity and mixing with water., Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-601, https://doi.org/10.5194/epsc2024-601, 2024.

We present the results of the implantation of energetic sulfur ions in icy samples (H₂O:C₃H₈ and H₂O:C₃H₇OH) in temperature conditions relevant to Europa and other Jovian satellites. The surface of the Jovian moons experiences an intense bombardment of energetic particles, including sulfur ions over a large range of energy[1][2]. Any organic matter emplaced onto the surface from the internal ocean would be processed by this bombardment, with the possibility for sulfur to be included into the resulting products. As a results, the future space missions to the galileans moons (NASA’s Europa Clipper and ESA’s JUICE) may encounter such processed organic matter, which will complicate the characterization of the organic matter from the interior. The MASPEX [3] and SUDA [4] instruments in particular will get the opportunity to characterize the organic matter on Europa’s surface with unprecedented sentitivity and mass resolution.

Here, in temperature conditions relevant to Europa (80 K), we investigate the composition of the organic residues generated by the irradiation of a water:propane ice and a water:propanol ice with a 105 keV S⁷⁺ ion beam. Propane is the simplest alkane that can be condensed at a temperature relevant to Europa’s surface, and propanol is the corresponding alcohol. The irradiated samples were slowly warmed up to 300 K to sublimate the volatiles and leave the refractory organic residues. The residues were analyzed with Ultra-High Resolution Mass Spectrometry using two ionization techniques (laser desorption and electrospray).

The analysis of the residue from the irradiation of the water:propane ice shows a very diverse (2000 + unique formulas) organic matter, with heavy molecules (up to m/z>800). We find large numbers of aromatic CH species (Figure 1, left) and oxygen-rich, less aromatic species, depending on the ionization technique used. Organosulfurs are found both in CHS form and CHOS; they are minor both in number and intensity, but demonstrate the possibility of forming organosulfurs in the surface conditions of Europa through sulfur implantation with any organic. [5]

The residue resulting from the water:propanol sample, as seen with laser desorption is very similar, without any noticeable difference between the number and intensity of O-bearing annotations, or aromaticity (Figure 1). Twice as many CHS annotations are found in the water:propanol residue compared to water :propane.

The dose used in our study represents a geologically short time on the surface of Europa (from a few days to a few thousands of year, depending on the region considered). This indicates that the properties of organic precursors may swiftly be erased by radiation processing on the surface. Future work with different doses and precursor species will better constrain how radiation chemistry alters organic signatures on the surface.

[1] J.F. Cooper, et al.,.  Icarus, 149(1), 133-159. (2001)

[2] C. Paranicas et al.,., Europa. U. Arizona Press, Tucson, 529 (2009)

[3] Waite Jr, J. H., et al.  Space Science Reviews 220.3 (2024): 30.

[4] Goode, W., et al. Planetary and Space Science, 227, 105633. (2023).

[5] Bouquet, A., et al. The Planetary Science Journal, 5(4), 102 (2024).

Fig1 : #C vs DBE (Double Bond Equivalent) of the annotations obtained by Laser Desorption Ionization – Fourier Transform Ion Cyclotron Resonance (LDI-FTICR) applied to the residue of the S-implanted Water :Propane Ice (left) and Water :Propanol Ice (right).

How to cite: Bouquet, A., Pires da Costa, C., Boduch, P., Rothard, H., Domaracka, A., Danger, G., Schmitz, I., Afonso, C., Schmitt-Kopplin, P., Hue, V., Nordheim, T., Ruf, A., Duvernay, F., Napoleoni, M., Khawaja, N., Postberg, F., Javelle, T., Mousis, O., and Tenelanda-Osorio, L.: Implantation of sulfur ions into water-propane and water-propanol ices : formation of refractory organic matter with organosulfurs, and implications for Europa’s surface, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-600, https://doi.org/10.5194/epsc2024-600, 2024.

The plumes of Enceladus contain a non-ice component that originates from aqueous processes occurring within the interior ^1,2. The ocean of Enceladus is thought to be connected to the surface across a range of time scales. These processes range from the rapid eruption of cryovolcanic plumes to slow crustal convection on geological timescales^3,4. In every case, the system will have a temperature and geochemical evolution as it freezes, with the history of evolution recorded in the sequence of mineral precipitation. Analogously to igneous and metamorphic petrology, we can explore the mineralogy and its context to reconstruct the history of that sample. Most importantly, for astrobiological investigations, the formation and cryo-petrological study of inorganic salts can be used to identify sites of recent exposure on the surface.

Synchrotron X-ray techniques allow fast, high-resolution probing of these systems with X-ray light. By exploring large, multi-component samples with multiple techniques, with variable temperature over time we can reveal many emergent processes that may not be predictable with simple phase diagrams.

We use a combination of synchrotron powder X-ray diffraction (PXRD) and X-ray microtomography (µCT) across multiple beamlines at Diamond Light Source (I11, I12 and DIAD). Using a multi-modal approach, we present an in-situ study of the low-temperature phase behaviour of Na-Cl-HCO₃ fluids. We employ K11-DIAD (Dual Imaging and Diffraction) to carry out ‘image-guided diffraction’ on an Enceladus-type sample frozen in real-time. DIAD’s unique capabilities allow us not only to study microstructure down to 1 µm but also to carry out spatially resolved XRD and identify solid phases present.

We present, for the first time, the use of dual imaging and diffraction of a Na-Cl-CO₃ solution frozen in real time in 3 dimensions [Figure 1]. DIAD’s imaged guided diffraction provides spatially-resolved XRD, allowing us to probe different regions of our sample and identify the formation of Na₂CO₃ hydrates. We show the influence of carbonate chemistry on the sequence of cryogenic precipitation and the development of complex microstructures. These results provide insights into crustal transport processes and will help with interpreting observational data from upcoming Galilean missions.

[1] Postberg F, Schmidt J, Hillier J, Kempf S, Srama R. A salt-water reservoir as the source of a compositionally stratified plume on Enceladus. Nature 2011; 474: 620–622.

[2] Sekine Y, Shibuya T, Postberg F, Hsu H-W, Suzuki K, Masaki Y et al. High-temperature water–rock interactions and hydrothermal environments in the chondrite-like core of Enceladus. Nat Commun 2015; 6: 8604.

[3] Schoenfeld AM, Hawkins EK, Soderlund KM, Vance SD, Leonard E, Yin A. Particle entrainment and rotating convection in Enceladus’ ocean. Commun Earth Environ 2023; 4: 28.

[4] Vance SD, Journaux B, Hesse M, Steinbrügge G. The Salty Secrets of Icy Ocean Worlds. JGR Planets 2021; 126: e2020JE006736

How to cite: Perera, L., Day, S., Thompson, S., Leonardi, A., and Ahmed, S.: Using synchrotron X-ray diffraction and X-ray tomography to study ocean world cryogeochemistry in 4D., Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1090, https://doi.org/10.5194/epsc2024-1090, 2024.

Vast subsurface oceans buried under kilometers of ice crust have been discovered in our Solar System's icy moons and have sparked worldwide interests in ascertaining their potential habitability. The tell-tale signs that betray their presence on their hosts are mostly related to density and gravitational field measurements. In the case of Saturn’s moon Enceladus however, the Cassini space probe has observed supersonic plumes of water vapour and ice particles spewing from a fractured area of the South Polar Terrain called the "tiger Stripes", with later analysis of their composition confirming the presence of liquid water below the surface. While the plumes mechanisms are now well-understood as a whole, some areas remain unclear such as the link between icy particles nuclei composition and their origin and evolution from the subsurface ocean. As future missions will renew contact with Enceladus and explore its mysteries in the coming decades, we need experimental studies to best prepare for those. These studies will help with mission planning, instruments choice and tests and making sure we will harvest the best scientific return from the observations made.  In this paper we present a new experimental setup called the Plumes and Ices Simulation Chamber for Enceladus and icy moonS, or PISCES for short. It is designed to emulate the environmental conditions (pressure, temperature) at the surface and interior of icy moons to experimentally study the processes that occur there using a wide range of sensors and instruments. We first describe the vacuum chamber setup and the range of sensors and instruments it can interface with. To showcase the setup's capabilities, we will then proceed to detail some of the plumes experiments we've run. Using 3D-printed cylindrical channels of various shapes and profiles and mounting them atop a liquid water reservoir placed in the vacuum chamber, we can investigate a wide range of plumes and link the plumes behaviour (vent velocity, temperature or particle size) to subsurface characteristics e.g. wall temperature, width, length or expansion ratio. By steadily increasing the complexity of the models used, we aim to experimentally replicate the icy plumes of Enceladus under analogous conditions using the PISCES setup will be a pioneering achievement this new area of research.

How to cite: Bourgeois, Y. and Cazaux, S.: PISCES: Plumes and Ices Simulation Chamber for Enceladus and icy moonS, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-742, https://doi.org/10.5194/epsc2024-742, 2024.

Introduction

                Enceladus, an icy moon of Saturn, has a subsurface ocean with large geysers that originate from hydrothermal vents. A solvent, like liquid water, and a source of energy, such as a hydrothermal vent, are both key elements in creating an environment habitable to life and are involved in theories of its origin [1]. Modelling of the interior of Enceladus suggests its silicate core is composed of undifferentiated material like that found on carbonaceous asteroids and comets [2], which are known to contain amino acids, the building blocks of life [3,4]. Understanding how Enceladus’s sea floor alters will increase the knowledge of the geology surrounding its hydrothermal vents.

               Sampling of material from Enceladus’s geysers by the Cassini mission suggests hydrothermal metamorphism is occurring at temperatures of at least 150°C [2]. To better understand hydrothermal processing on Enceladus, we have heated a carbonaceous asteroidal simulant in water at 150°C to study the alteration products that formed.

Methods

                CM-E carbonaceous chondrite simulant intended to be representative of the ‘Mighei-like’ carbonaceous (CM) chondrite Murchison was acquired from Space Resource Technologies, with 1.4 cm³ (1.45 g) placed in a 45 ml acid digestion vessel with 22 ml of distilled water and sealed in an inert N₂ atmosphere. The vessel was then heated at 150°C for 33 days. The pressure that resulted is calculated to be 6 bars. To study changes in mineralogy, high resolution synchrotron X-ray diffraction (XRD) data was collected at the I11 beamline at Diamond Light Source both for unaltered simulant and the hydrothermally processed simulant. Proportions of different minerals were determined by Rietveld refinement using Topas 4.2. To study the composition of the liquid after hydrothermal alteration, the water from the experiment was extracted with a 450 μm diameter syringe and was analysed by X-ray fluorescence (XRF) using a PANalytical Epsilon3 XL with an Ultralene filter at the Materials Characterisation Laboratory at ISIS Neutron and Muon Source.

Results and Discussion

                The CM simulant is a heterogeneous mixture of components meant to recreate textures observed on carbonaceous asteroids [6] and exact proportions of minerals are bound to vary from sample to sample. However, even given this, there are distinct differences between the mineralogy of the simulant used and the CM chondrite it is modelled after (Table 1). CM chondrites are composed mostly of serpentine minerals and tochilinite [5], whereas the simulant used is mostly made out of montmorillonite (Table 1), which lacks Fe and contains more abundant Al, Ca, and Na. Additionally, minerals that are either absent from CM chondrites or occur as terrestrial alteration products, like sulphates, pyrite, hematite, and quartz were present in the simulant (Table 1).

                The differences between the simulant and CM chondrites defined the alteration products observed. The altered simulant contains significant amounts of feldspars and sulphates. The feldspars are likely the result of olivine and pyroxene decomposing and reacting with the montmorillonite. The K-feldspar produced is likely adularia, a low temperature hydrothermal mineral [7], while the plagioclase likely resulted as albitization (replacement of feldspar by albite) of adularia, which also occurs under low temperature hydrothermal conditions [8]. Rozenite and epsomite are sulphates in the altered simulant which were likely produced by reactions with gypsum and pyrite and other minerals (e.g., olivine) within the simulant. If CM chondrite material were used, it is likely serpentine and sulphide minerals (e.g., pyrrhotite) would be produced instead, but the breakdown of olivine and pyroxene still would have occurred as observed here.

                The water extracted from the autoclave following the experiment was cloudy with small particulates still suspended in it. The particulates could not be separated from the water without significant water loss so were measured alongside the water. The water mixture was found to contain an abundance of Si (Table 2), which may be attributed to sub-mm silica particles. The sizes of these silica particles are unknown, however nanometre Si-rich particles are found in Enceladus’s plumes and other similar hydrothermal environments from a reaction related to clay minerals [9]. The concentration of Si observed here is consistent with that in Saturn’s E-ring, which is produced by Enceladus [9]. However, despite this similarity, no Na was found in the water mixture (Table 2), indicating that any Na present is inside the solid sample, which is dissimilar to Enceladus’s Na-rich ocean. The montmorillonite hydrothermally altered here is chemically different than the material making up Enceladus’s core, however hydrothermal alteration of a clay mineral is likely occurring on Enceladus.

Conclusions

                The recreation of hydrothermal processes on Enceladus using CM chondrite simulant resulted in the breakdown of olivine and pyroxene and the production of feldspars. This reaction is likely the result of the CM chondrite simulant containing relatively high aluminium and alkali elements compared to CM chondrite meteorites. The fluid extracted contained sub-mm particulates rich in Si and lacking in Na. The CM simulant is not chemically analogous to the seafloor of Enceladus however its clay rich nature does give it some degree of similarity.

Acknowledgements

                We thank Sarah Day and Lucy Saunders for assisting with sample preparation and XRD data collection. We also thank Gavin Stanning and Daniel Nye for use of their XRF and assistance with XRF data collection. We would like to thank Raul Montes for assistance in calculating the pressures produced in this experiment.

References

[1] Corliss et al. (1981) Oceanol. Acta., 4: 59-70. [2] Sekine et al. (2015) Nat. Commun., 6: 8604. [3] Botta et al. (2002) Orig. Life. Evol. Biosph., 32: 143-163. [4] Altwegg et al. (2016) Sci. Adv., 5: e1600285. [5] Howard et al. (2011) Geochim. Cosmochim. Acta., 75: 2735-2751. [6] Britt et al. (2019) MAPS, 54: 2607-2082. [7] Steiner (1970) Mineral. Mag., 37: 916-922. [8] Chowdhury & Noble (1993) Mar. Pet. Geol. 10: 394-402. [9] Hsu et al. (2015) Nature, 519: 207-210.

How to cite: Jenkins, L., Thompson, S., and Connolly, E.: Simulating with a Simulant: Recreating Hydrothermal Metamorphism on Enceladus, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-451, https://doi.org/10.5194/epsc2024-451, 2024.

Carbonaceous organic matter (COM), between 20 and 50%, is needed to model the rocky core of icy bodies (Neri et al, 2020, Reynard & Sotin. 2023), and account for their mass, moment of inertia, and density as measured by the Cassini, Galileo and Juno missions. However, the effects of temperature and pressure on COM at conditions of the rocky cores (up to ~7 GPa and 1300 K) have not been taken into account in these preliminary models. We present an experimental characterization of the evolution of COM at elevated temperature and pressure to describe its density evolution during thermal evolution of icy bodies. Carbonaceous organic matter undergoes important transformations both in terms of composition and structure when subjected to an increase in temperature and pressure. These transformations are characterized by the loss of heteroatoms (O, H, N, S) and a structural rearrangement which lead to a variation of density from 1200 kg/m³ at 300 K to 2300kg/m³ at 1300 K.

We first performed determinations of the ambient temperature compressibility of COM analogs using diamond anvil cell experiments. Kerogens and glassy carbons were used as analogs of COM. Second, we adapted the Vitrimat kinetic model of kerogen chemical and density evolution as a function of temperature and time (Burnham 2019). This modification accounts for chemical evolution determined on samples heated at temperatures of 473-723 K for times ranging from seconds to 100 days, and at various pressures (0.2-2.5 GPa). Combining these two studies allows us to describe the density evolution of COM as a function of time, temperature and pressure, assuming it behaves like kerogens.

Thermo-chemical evolution models are coupled with this equation to determine the time evolution of the density structure of icy bodies and compare it with available observations. In addition to density evolution of COM in the core, heteroatoms are released as volatiles (mainly H₂O, CO₂, CH₄). They may form new species in the core (carbonates) and the high-pressure ice level (clathrates), reach the ocean, and be released to the upper ice level, then to space. Models will also provide estimates of volatile fluxes and formation of new compounds on the density structure.

Improvements of density determinations of COM analogs will provide accurate models for predicting the density and thermal evolutions compatible improved determinations of internal structures of icy moons from the JUICE and future Europa Clipper and Dragonfly missions, and observation of dwarf planets by JWST.

Burnham, A. K. Kinetic models of vitrinite, kerogen, and bitumen reflectance. Organic Geochemistry 131, 50-59 (2019). https://doi.org/https://doi.org/10.1016/j.orggeochem.2019.03.007

Néri, A., Guyot, F., Reynard, B. & Sotin, C. A carbonaceous chondrite and cometary origin for icy moons of Jupiter and Saturn. Earth and Planetary Science Letters 530, 115920 (2020). https://doi.org/https://doi.org/10.1016/j.epsl.2019.115920

Reynard, B. & Sotin, C. Carbon-rich icy moons and dwarf planets. Earth and Planetary Science Letters 612, 118172 (2023). https://doi.org/https://doi.org/10.1016/j.epsl.2023.118172

How to cite: Delarue, C., Reynard, B., and Sotin, C.: Density of carbonaceous organic matter in icy bodies, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-424, https://doi.org/10.5194/epsc2024-424, 2024.

Recent interpretations of space observations suggest that the icy moons of Jupiter and Saturn and the dwarf planet Ceres formed by accreting silicates, sulfides, ices and primordial organics. During accretion and differentiation of these icy bodies, the primordial organics reacted with water. We have carried out laboratory experiments at (P,T) conditions relevant to the interiors of icy moons and dwarf planets to investigate the degradation of the organics with water. The goal is to determine the ions that are eventually dissolved in the ocean and the chemical composition and structure of the refractory organics that mix with silicates and sulfides to form the core of these bodies. The primordial organics are analogs made in the Nebulotron. A recent analysis (Lévêque et al., 2024) demonstrated that these organics have elementary and chemical composition close to that of the organic matter found in the Paris meteorite, which is a carbonaceous chondrite, one of less altered CM chondrites. These organic molecules were mixed with water and placed in three different pressuring devices covering a large domain of pressures (up to 2 GPa) and temperatures (at 200°C and 400°C) conditions relevant to the interior of icy bodies.

Gas chromatography has been carried out on sealed capsules reacted in internally heated pressure vessel. In situ Raman spectroscopy and in situ XRD have been carry out on samples pressurized in a Diamond Anvil Cell (DAC). Each device provides complementary information on the evolution of the organic matter solid residues and its byproducts. Gas analyzes and in situ Raman demonstrate that N₂ and CO₂ are released when OM:H₂O mixtures are heated up to 200°C, and CH₄ appears at 400°C. Organic matter (OM) evolves towards very condensed PAHs. Being denser than the ocean, that should mix with silicates and sulfides to form a refractory core that further evolves as the temperature raises due to the decay of the long-lived radioactive elements. The primordial OM reacts with water to produce ions which may form carbonates, as observed by our XRD analyzes. These experiments provide potential explanations for the presence of N₂ and CH₄ in Titan’s atmosphere and for the presence of  carbon-rich regions observed at the surface of Ceres, Europa and Ganymede.

How to cite: Lévêque, P., Bollengier, O., Afonso, C., Bujoli, B., Champallier, R., Hertzog, J., Le Menn, E., Marrocchi, Y., Queffelec, C., Schmitz, I., Slodczyk, A., and Sotin, C.: Laboratory experiments on primordial organic degradation at conditions relevant to ocean worlds interiors, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-751, https://doi.org/10.5194/epsc2024-751, 2024.

Results from the Cassini mission at Enceladus revealed the presence of a diverse organic inventory [1,2] in its subsurface ocean as well as ongoing hydrothermal activity at the water-rock interface [3,4]. Ice grains ejected into the plume are thought to contain compounds originating from the depths of the ocean, which are likely linked to hydrothermal (bio)geochemistry, as are other constituents in the vapour phase [1,2,5]. Understanding the nature and effects of hydrothermal activity on Enceladus and other icy ocean worlds (e.g. Europa) is crucial for evaluating the prospects of habitability as well as understanding how potential biosignatures may manifest in spacecraft data. Biosignatures that are present on the ocean floor may be chemically altered by the elevated temperature and pressure conditions in such environments, as well as by salts, mineral catalysts, or other solutes in hydrothermal fluids.

Analogue mass spectra, generated in the laboratory using the laser-induced liquid beam ion desorption (LILBID) technique [6], are a useful tool for interpreting impact ionisation mass spectra, as produced by Cassini’s mass spectrometer – the Cosmic Dust Analyzer (CDA). Thus, impact ionisation mass spectra of both hydrothermally processed and unprocessed material in ice grains obtained via spaceborne instruments can be recreated. Given the ubiquity of peptides utilised by all known life on Earth, Khawaja et al. [7] recently investigated the hydrothermal evolution of the simplest tripeptide – triglycine (GGG) - as both a potential biosignature and marker for hydrothermal activity. This work verified significant differences between the spectra of processed and unprocessed GGG, outlining an approach to verify a unique spectral fingerprint as evidence for the former. Here, we briefly discuss the results from the hydrothermally processed GGG, with similarities between the spectra before and after processing compared. We demonstrate that the presence of processed GGG can be elucidated with a two-step process: a) GGG is, in general, identified by the appearance of glycine, diglycine, and GGG peaks, along with common fragments indicative of peptides and N-bearing compounds, and b) processed GGG is identified by the additional presence of unique peaks related to products formed exclusively by the hydrothermal processes. In addition, certain peaks related to compounds not present in the initial solution appear in both spectra – e.g. a peak at m/z 115 in the cation spectrum assigned to diketopiperazine. The potential implications of such results are discussed briefly here and will form the basis of more detailed future investigations. We will apply our methodology used to deduce the presence of hydrothermally processed GGG to peptides of longer chain length and containing different amino acid constituents.

We also examine the influence of salts (NaCl) on the hydrothermal processing of GGG at pH 8.5-10, conditions typical for the ocean-core interface of Enceladus, and the peptide’s appearance in impact ionisation mass spectra. Previous experiments [8-10] have demonstrated that salts can suppress and alter expected organic features in LILBID and, by extension, impact ionisation mass spectrometry. Salinity and acidity are also thought to influence reaction pathways in hydrothermal chemistry [11-13]. This multi-faceted influence of salts presents significant implications for the detection of potential molecular biosignatures from icy ocean worlds with saline oceans (i.e. Enceladus and Europa). The solubility of GGG generally increases with greater departure from a neutral pH (i.e. more acidic or alkaline) and with salinity [14]. This is an important factor that not only influences the detectability of triglycine but also its behaviour as a biomolecule. The role of potential catalytic minerals relevant for the expected seafloor composition of Enceladus is also discussed in this work.

[1] Postberg, F. et al. (2018) Nature 558, 564–568.

[2] Khawaja, N. et al. (2019) MNRAS 489, 5231–5243.

[3] Postberg, F. et al. (2011) Nature 474, 620–622.

[4] Hsu, H.-W. et al. (2015) Nature 519, 207–210.

[5] Waite, J. H. et al. (2017) Science 356, 155–159.

[6] Klenner, F. et al. (2019) Rapid Commun. Mass Spectrom. 33, 1751–1760.

[7] Khawaja, N. et al. (2024) Phil. Trans. R. Soc. A. 382, 20230201.

[8] Klenner, F. et al. (2020) Astrobiology 20, 1168–1184.

[9] Napoleoni, M. et al. (2023a) ACS Earth Space Chem. 7, 735–752.

[10] Napoleoni, M. et al. (2023b) ACS Earth Space Chem. 7, 1675–1693.

[11] Xia, L. et al. (2020) Chem. Geol. 541, 119581.

[12] Hammerton, J. M. & Ross, A. B. (2022) Catalysts 12, 492.

[13] Aspin, A., et al. (2023) Geophys. Res. Lett. 50, e2023GL103738.

[14] Lu, J., et al. (2006) J. Chem. Eng. Data 51, 1593–1596.

How to cite: O'Sullivan, T., Khawaja, N., Hortal Sánchez, L., Napoleoni, M., Bloema, J., Hillier, J., and Postberg, F.: Detecting hydrothermally processed peptides in the mass spectra of ice grains emitted by Enceladus and Europa, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-919, https://doi.org/10.5194/epsc2024-919, 2024.

Introduction: Characterizing the geochemistry of icy ocean worlds such as Europa and Enceladus is a key step to better constrain the habitability of their subsurface oceans. Transition metals with several oxidation states, such as iron, may be tracers of the oxidation state of icy ocean moon interiors. Their detection, and the characterization of their oxidation states, in Europa’s or Enceladus’ ice grains would provide valuable new data about the geochemistry of both the subsurface oceans and surface processes. Indeed, ice grains are ejected from both moons either in plumes and/or by micrometeorite bombardment, and their analysis can give valuable insight into the composition of subsurface liquid reservoirs. Impact ionization mass spectrometers such as the SUrface Dust Analyzer (SUDA; Kempf et al. 2024) onboard the upcoming Europa Clipper mission can analyze ejected ice grains and detect ocean-derived salts therein.

Methods: To determine if SUDA-type mass spectrometers are capable of detecting iron in different oxidation states, we recorded analogue mass spectra using the Laser Induced Liquid Beam Ion Desorption (LILBID), a technique shown to accurately reproduce data of spaceborne impact ionization mass spectrometers probing ocean worlds (e.g., Postberg et al. 2009, Klenner et al. 2019). Here, we measured Fe²⁺ and Fe³⁺ sulfates and chlorides with LILBID, thus determining the mass spectral appearances of these salts as if encased in ice grains from Europa or Enceladus and detected by SUDA-type instruments.

Results: Our results show that impact ionization mass spectrometers can detect and differentiate ferrous (Fe²⁺) from ferric (Fe³⁺) ions in both cation and anion modes owing to their tendency to form distinct ionic complexes with characteristic spectral features (Napoleoni et al. 2024). Peaks bearing Fe³⁺, such as [Fe³⁺ (OH)₂]⁺ and [Fe³⁺ (OH)_a Cl_b]^- are particularly important for discriminating between the two oxidation states of iron in the sample and even allow quantification of the two species.

Implications for Europa Clipper. This study indicates that SUDA could be a useful tool for the characterization of the oxidation state of the subsurface ocean of Europa by quantification of iron-bearing salts in Europa’s ice grains. In both our analogue experiments and future SUDA mass spectra, the intensities of Fe-bearing ions of different oxidation states and the isotope distribution patterns are informative features that can be used to determine the presence and oxidation state of iron-bearing compounds. The recorded LILBID mass spectra complement a spectral library (Klenner et al. 2022) providing analogue data for SUDA onboard Europa Clipper and potential future Enceladus missions.

Implications for the geochemistry of ocean worlds. The recorded LILBID mass spectra could allow the detection of iron (a key element for life) and the characterization of its oxidation state on the surfaces of icy moons, and potentially from their subsurface oceans (Figure 1). We draw implications for the pH values and oxidation state of Europa’s and Enceladus’ subsurface oceans for difference cases of (non) detection and characterization of iron in ice grains, considering both surface ejecta and plume ice grains. Such characterization of the geochemistry of Europa or Enceladus could be used to test and further develop different models of redox chemistry in their oceans (Ray et al. 2021). It could also have important implications for hydrothermal processes and potential metabolic pathways, such as iron reduction metabolisms (Roche et al. 2023), that may be used by possible extant life in icy moons’ oceans.

Figure 1. Simplified interpretations of the (non) detection and characterization of iron in ice grains from ocean worlds with SUDA-type instruments. From Napoleoni et al., 2024. Three scenarios are considered: (a) detection of Fe(II)-dominated grains; (b) detection of significant Fe(III) in ice grains; (c) no Fe detection. In addition to iron, the detection of aluminum ions (Al³⁺) in ice grains would support a salt source from an acidic ocean composition. In both scenarios (a) and (b), the case of ice grains originating from a plume (i.e., fresh surface material) is distinct from ice grains originating from the surface, where older material has likely undergone oxidation. In the case of surface material, the age of this material may be constrained by investigating its surface appearance, including geological features.

References

Kempf et al. (2024) Space Science Reviews, in review.

Klenner et al. (2019) Rapid Commun. Mass Spectrom., 33(22), 1751-1760

Klenner et al. (2022) Earth and Space Science, 9(9), e2022EA002313

Napoleoni et al. (2024) The Planetary Science Journal, 5(4), 95

Postberg et al. (2009) Nature, 459, 1098

Ray et al. (2021) Icarus, 364, 114248

Roche et al. (2023) International Journal of Astrobiology, 22(5), 539-558

How to cite: Napoleoni, M., Hortal Sánchez, L., Khawaja, N., Abel, B., Glein, C., Hillier, J. K., and Postberg, F.: Detecting Fe (II) and Fe (III) in Ice Grains with Mass Spectrometry: Implications for the Geochemistry and Habitability of Europa and Enceladus, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-974, https://doi.org/10.5194/epsc2024-974, 2024.