MITM10
In the laboratory, the analyses of cosmo-materials coming from planetary or asteroidal objects (that felt on Earth or returned by space missions) as well as analyses on analogues reproducing their physical/chemical properties, are both essential for the understanding of the history of planets and small bodies.
The results of these laboratory experiments are essential for the interpretations of measurements obtained by ground-based observations and space missions. They are also necessary for planning and preparing future in situ and sample-return space missions, ensuring their success in collecting valuable samples and data.
In this session, we invite submissions related to the analysis of cosmo-materials and to the production, evolution and analysis of planetary and small bodies analogues (interpretation of chemical/physical properties, predictions, preparation of analytical tools or space instruments, preparation of analytical chain for sample return analyses, etc.). Laboratory experiments necessary to interpret data of any past, present and future space missions will be particularly encouraged.
Session assets
Understanding the physics of granular materials in a low gravity and vacuum environment is essential to predict the regolith behavior on the Moon and asteroids. Cohesive forces - interparticle attractive forces, are an important parameter to consider in the regolith dynamics. A given cohesive force may be considered negligeable in Earth’s gravity but become dominant when the gravitational acceleration is reduced (e.g. [1]). The surface properties, such as cohesion, influence the response of planetary surfaces (e.g., will an object sink or bounce?) and the performance of space missions (e.g., will a lander sink or bounce, how will a sampling arm perform?). The sinkage of an object, such as a CubeSat after landing or a boulder resting on fine regolith, enables estimates to be made of the bearing capacity of the surface – maximum load the surface can withstand before rupturing.
To quantify the importance of cohesive forces on the sinkage depending on the gravitational acceleration, sinkage experiments into granular materials were performed at different levels of cohesion and gravitational acceleration. The experiment campaign named SILOE (Surface Investigation in Low gravity Environment) was conducted in December 2024 in the GraviTower Bremen Pro at the ZARM drop tower facility (Bremen, Germany). The sinkage experiments were performed in terrestrial gravity (9.8 m/s²) and in two reduced gravitational accelerations: Mars gravity (3.8 ± 0.2 m/s²), and Moon gravity (1.8 ± 0.2 m/s²). These two levels of low gravity are achieved using the GraviTower in partial gravity.
The SILOE sinkage experiments (fig. 1) consist in the release of a spherical projectile (D = 25 mm, stainless steel) into a tray filled with a granular material. The projectile is released from a constant drop height of 6 mm above the surface. The associated collision velocities range from 0.1 to 0.5 m/s, depending on the gravitational acceleration. The experiments are conducted under low to medium vacuum conditions (50 – 400 Pa), to remove the interstitial air pockets and water molecules inside the material.
Figure 1: Design of the SILOE experiment.
The granular materials (fig. 2) studied are glass beads (120 µm) and quartz sand (500 µm). To increase the cohesive forces of the glass beads, the material was covered by a polymer coating enabling the addition of liquid capillary forces [2]. The cohesive force is controlled by the coating thickness applied to the beads. Glass beads with three levels of cohesion were produced following the preparation technique presented in Gans et al. (2020) [2]: at 50, 200, and 400 Pa (cohesive shear stress).
Figure 2: Granular materials used in the SILOE experiments.
The sinkage, defined as the final penetration depth of the projectile, is measured by tracking the vertical displacement of the projectile using a camera (sampling rate: 240 Hz) and a laser profilometer (sampling rate: 340 Hz), placed on the side and top of the chamber, respectively.
Cohesion increases the surface strength, which leads to smaller sinkage (fig. 3). In low gravity, the importance of cohesive forces increases, and smaller sinkage are observed for an identical material when the gravity is reduced. In the case of the very cohesive glass beads, rebounds can be observed (fig. 4).
Figure 3: Images captured with the camera after the projectile is dropped and finished sinking into the glass beads of different levels of cohesion (from cohesionless to very cohesive).
Figure 4: Projectile vertical displacement with respect to the surface (surface height at 0 mm) in vacuum and Earth gravity condition into the different cohesive glass beads.
The results of the SILOE drop tower campaign, and additional sinkage experiments performed at varied ambient pressure, will be presented during the conference. In addition to bringing a better understanding of cohesive forces with respect to gravity, the SILOE results will help to improve interpretations of the data from the upcoming ESA Hera mission (in particular with the CubeSat landings on asteroids Didymos and Dimorphos [3], and boulder tracks [4]), and the JAXA MMX mission (in particular the IDEFIX rover [5] on Phobos).
References
[1] Scheeres, et al. (2010). Scaling forces to asteroid surface: the role of cohesion. Icarus, 210, 2.
[2] Gans, Pouliquen, and Nicolas (2020). Cohesion-controlled granular material. Physical review E, 101:032904.
[3] Michel, et al. (2022). The ESA Hera mission: Detailed Characterization of the DART Impact Outcome and the Binary Asteroid (65803) Didymos. The Planetary Science Journal, 3:160.
[4] Bigot, Lombardo, et al. (2024). The bearing capacity of asteroid (65803) Didymos estimated from boulder tracks. Nature Communications, 15:6204.
[5] Michel, et al. (2022), The MMX rover: performing in situ surface investigations on Phobos. Earth, Planets and Space, 74:2.
Acknowledgements
This project is carried out with the support of the Education Office of the European Space Agency (ESA) under the educational Experiments Programme. This project received funding through the grant EUR TESS N°ANR-18-EURE-0018 in the framework of the Programme des Investissements d’Avenir, and the Bourse Espace 2024 scholarship by the Fondation Ailes de France. A.D. acknowledges PhD funding from University of Toulouse III, and C.R. acknowledges PhD funding from CNES and ISAE SUPAERO. This project benefitted from funding from CNES in the context of the Hera mission and the MMX rover/wheelcams, the French ANR (ANR-23-ERCC-0003-01), and the European Research Council (ERC) GRAVITE project (Grant Agreement N°1087060).
How to cite: Duchêne, A., Bigot, J., Stankiewicz, M., Dghais, S., Robin, C., Wilhelm, A., Kollmer, J. E., and Murdoch, N.: Sinking or bouncing in low gravity environments?, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-113, https://doi.org/10.5194/epsc-dps2025-113, 2025.
Neutrons are a powerful probe and vital tool for a wide range of scientific and industrial fields. Neutron scattering is used to obtain a direct and detailed insight into the structure and dynamics of condensed matter – matching dimensions in space from single atoms to macromolecules and in time from atomic vibrations to diffusion of large molecular units – all depending on the instrument and facility used. Compared to other scattering probes, neutrons are non-interacting and scatter off of the nucleus - allowing for much deeper penetration. This unique mechanism gives it the ability to ‘see’ hydrogen with high sensitivity, which is present in most molecules relevant to planetary and interstellar environments, and allows it to differentiate between isotopes. By exploiting the isotopic differentiation, such as using selective H/D substitution, we can also highlight interatomic correlations of interest. Another important advantage is that complex sample environments can be used, such as vacuum chambers and pressure cells, to recreate the conditions across various regions. This range of techniques has much to offer the Planetary Sciences and Astrochemistry communities and there is much to be gained from its increased use/collaboration. In this presentation, I will present what is on offer to these communities, starting with an introduction to the main techniques (diffraction, small-angle, dynamics, spectroscopy and imaging) and then I will go through examples of neutron work we have previously and are currently undertaking with relevance to both the Solar System and the Interstellar Medium (ISM).
The presentation will focus on some recent examples in detail. We have uniquely employed an in-situ ice vapour-deposition experiment (high vacuum) on the instruments NIMROD and Sans2d, at the ISIS Neutron and Muon Source in the UK, to study the structure of Amorphous Solid Water (ASW), as a function of growth and thermal evolution.1–3 Neutrons gave us the ability to directly probe (non-destructively) the general bulk structure of ASW, along with its porosity (volume fraction, pore sizes, shapes etc.), surface area and crystallinity, and how this all evolves with time and temperature. Altogether, the results converge to form a new picture of the ASW structure and nanoporosity during growth and annealing, involving microporous islands with voids between them (see Fig.1). This work has drastically changed our picture of ice astrophysics and the role it plays in planet- and star-formation processes.
Figure 1. Cartoon representation of the structure of ASW theorised in this work – islands/grains with voids between them (not to scale).
Another avenue of ice studies conducted using NIMROD and Polaris at the ISIS Facility led to the discovery of a new metastable dihydrate of sodium chloride at ambient pressure.2,4,5 Neutrons were key here with their particular sensitivity to the position of hydrogen, which makes up a large part of the NaCl water ice mixture. This dihydrate should be stable at the surfaces of icy worlds, such as Europa and Enceladus, and if it were detected then that would indicate regions of recent activity where subsurface brines have frozen rapidly, which are priorities for upcoming planetary missions, such as ESA’s JUICE and NASA’s Europa Clipper.
NIMROD and SANDALS at the ISIS Facility specialise in studying disordered materials such as liquids and glasses.2,7 They allow for the full structural characterisation of such a material and the interactions between all its components. One example of long-term work using both instruments is the study of the role of magnesium perchlorate (Mg(ClO4)2) in the subsurface water on Mars. Initially, it was found that the presence of Mg(ClO4)2 has a significant effect on the structure of water, making it appear as though it is under massive pressure, even when no external pressure is applied.6 Although this is the case, it was still found in a follow up study that amino acids, such as glycine in this case, can still self-assemble under these conditions, even though the Mg(ClO4)2 disrupts its hydration and hydrogen bonding ability.8 This happened more readily at low temperatures and so it seems possible to have biological molecules forming in the Martian environment. Finally, it was recently found that the presence of the osmolyte trimethylamine N-oxide (TMAO) could undo the pressuring effect of Mg(ClO4)2 on water, which would help prevent damage to biological systems.9
References
[1] Z. Amato, T. F. Headen, S. G ¨artner, P. Ghesqui `ere, T. G. A. Youngs, D. T. Bowron, L. Cavalcanti, S. E. Rogers, N. Pascual, O. Auriacombe, E. Daly, R. E. Hamp, C. R. Hill, R. K. TP and H. J. Fraser, Phys. Chem. Chem. Phys., 2025, 27, 6616–6627.
[2] ISIS, NIMROD, 2025, https://www.isis.stfc.ac.uk/Pages/nimrod.aspx, Accessed: 02-04-2025.
[3] ISIS, Sans2d, 2025, https://www.isis.stfc.ac.uk/Pages/Sans2d.aspx, Accessed: 02-04-2025.
[4] R. E. Hamp, C. G. Salzmann, Z. Amato, M. L. Beaumont, H. E. Chinnery, P. Fawdon, T. F. Headen,
P. F. Henry, L. Perera, S. P. Thompson and M. G. Fox-Powell, The Journal of Physical Chemistry Letters, 2024, 15, 12301–12308.
[5] ISIS, Polaris, 2025, https://www.isis.stfc.ac.uk/Pages/Polaris.aspx, Accessed: 02-04-2025.
[6] S. Lenton, N. H. Rhy, J. J. Towey, A. K. Soper and L. Dougan, Nat Commun, 2017, 8, 919.
[7] ISIS, SANDALS, 2025, https://www.isis.stfc.ac.uk/Pages/sandals.aspx, Accessed: 02-04-2025.
[8] H. Laurent, A. K. Soper and L. Dougan, Molecular Physics, 2019, 117, 3398–3407.
[9] H. Laurent, T. G. A. Youngs, T. F. Headen, A. K. Soper and L. Dougan, Communications Chemistry, 2022, 5, 116.
How to cite: Amato, Z., Headen, T. F., Dougan, L., Fox-Powell, M. G., Fraser, H. J., Hamp, R. E., Laurent, H., and Salzmann, C. G.: Neutron Scattering as a Powerful Tool for Studying Multi-Scale Structure for Planetary Sciences, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-129, https://doi.org/10.5194/epsc-dps2025-129, 2025.
Introduction:
The VNIR reflectance spectrum of a surface depends on its composition, physical properties, and the interactions between the surface and the environment. The temperature dependence of spectral properties may complicate the interpretation of planetary surfaces’ reflectance, but can also provide valuable information about their composition and state.
The VNIR reflectance spectra of common rock-forming minerals vary with temperatures [1][2][3][4], and these spectral changes can bias the interpretation of remote sensing data [5][6][4]. For example, Lucey et al. [7] showed that the A-type asteroids' spectra differ from those of olivines under terrestrial conditions but are consistent with those of olivines at the low surface temperatures expected on the main belt asteroids. Thereafter, Lucey et al. [8] detected temperature-dependent variations in the spectral properties of Eros, highlighting the importance of considering the effect of low temperatures on surface properties.
However, less has been done concerning carbonaceous chondrites. In this study, we report comparative low-temperature laboratory measurements of a panel of meteorites. This work may help us to understand the mineralogy of meteorites, but also to gain a better understanding of the solar system small bodies.
Samples:
We studied carbonaceous chondrites from four different groups (CI, CM, CV, and CO), one ungrouped carbonaceous chondrite (UCC), an ordinary chondrite, and a HED meteorite (diogenite). More specifically, we used the CI Orgueil, the CMs Murchison and DOM 08003, the CVs QUE 94688 and Axtell, and the CO ALH 85003. The meteorite Tarda was used (UCC). Additionally, we studied the ordinary chondrite LL Saint-Severin and the diogenite Bilanga, whose possible parent body is the differentiated asteroid Vesta.
Measurements:
Low-temperature reflectance spectroscopy measurements were acquired at IPAG (France) using the bidirectional reflectance spectrogonio-radiometer SHINE (SpectropHotometer with variable INcidence and Emergence) [9]. Spectra were acquired from 400 to 4000 nm with an incidence angle of 0° and an emission angle of 20°. SHINE was coupled with the double environmental chamber CarboN-IR [10]. With this setup, we performed measurements from about 280 K to a minimum of 70 K with several intermediate temperature steps. The temperature error is estimated to be 1 K and the measurements were led in an Ar-filled inner cell, ensuring good thermalization to the granular samples. All of our samples were in the form of powder.
Results and implications for space missions:
Spectral changes induced by temperature were observed for all classes of meteorites, and these changes were generally linear as a function of temperature.
With decreasing temperatures, the band at 1000 nm associated with olivine and/or pyroxene generally becomes deeper (Bilanga, Axtell, QUE 94688) and narrower (Bilanga, Saint Severin, Axtell) (Figure 1 A, D). There is no trend in the change in minimum reflectance values associated with temperature variations, but the position of the minimum may shift towards longer (Axtell) or shorter (Bilanga) wavelengths.
Concerning the band at 2000 nm associated with pyroxene, although the minimum reflectance values do not seem to vary with temperature, the band shifts towards shorter wavelengths (Bilanga, Saint Severin, ALH 85003) (Figure 1 B, E). In addition, the band deepens (Bilanga, Saint Severin, ALH 85003) with decreasing temperatures. The only significant change in bandwidth is for Bilanga, for which the band becomes narrower.
With decreasing temperatures, the band at 3000 nm shifts towards longer wavelengths (Bilanga, DOM 08003, Tarda). In general, the band deepens (Bilanga and DOM 08003) and becomes narrower (Orgueil, Bilanga, Axtell, and DOM 08003). The slope between 2900 and 3900 nm increases at low temperatures (Orgueil, Bilanga, Saint-Severin, ALH 85003, QUE 94688, Murchison, DOM 08003) (Figure 1 C, F).
Other spectral features can be impacted by changes in temperature such as the maxima at 550 nm and 1500 nm, and the band at 700 nm.
Our results are important for the analysis of sample returns from the Hayabusa, Hayabusa2, and OSIRIS-REx missions, and the remote sensing measurement interpretations of the JAXA/MMX, ESA/Hera, ESA/Ramses, and JAXA Hayabusa2 extended missions. For example, the spectral properties of Phobos in the VNIR show that it could be analogous to a carbonaceous chondrite. Its surface temperatures vary significantly from 130 K to 350 K [11]. For a correct interpretation of the surface properties by the MMX Infrared Spectrometer (MIRS) [12], it is necessary to consider the spectral variations induced by temperature variations.
Figure 1: Reflectance spectra at different temperatures of (A) Bilanga, (B) Saint-Severin, and (C) DOM 08003. (D) shows the 1000 nm bandwidth changes for Bilanga. (E) shows the minimum reflectance of the 2000 nm band of Saint-Severin, and (F) shows the slope changes for DOM 08003.
Conclusion:
Our work shows the importance of surface temperature in the interpretation of VNIR reflectance spectra. Based on our present sample set, it seems that the spectral alterations generally show similar trends between ordinary chondrites, carbonaceous chondrites and achondrites. The data interpretation of several space missions may be affected by the present work, and future improvements of the quality and spectral resolution of the space mission measurements will increasingly necessitate taking into account the spectral alteration due to surface temperature.
References:
[1] Singer, R. B., & Roush, T. L. (1985).
[2] Roush, T. L., & Singer, R. B. (1986).
[3] Schade, U., & Wäsch, R. (1999).
[4] Moroz, L., Schade, U., & Wäsch, R. (2000).
[5] Roush, T. L., & Singer, R. B. (1987).
[6] Hinrichs, J. L., Lucey, P. G., Robinson, M. S., Meibom, A., & Krot, A. N. (1999).
[7] Lucey, P. G., Keil, K., & Whitely, R. (1998).
[8] Lucey, P. G., Hinrichs, J., Kelly, M., Wellnitz, D., Izenberg, N., Murchie, S., ... & Bell III, J. F. (2002).
[9] Brissaud, O., Schmitt, B., Bonnefoy, N., Doute, S., Rabou, P., Grundy, W., & Fily, M. (2004).
[10] Beck, P., Schmitt, B., Cloutis, E. A., & Vernazza, P. (2015).
[11] Giuranna, M., Roush, T. L., Duxbury, T., Hogan, R. C., Carli, C., Geminale, A., & Formisano, V. (2011).
[12] Barucci, M. A., Reess, J. M., Bernardi, P., Doressoundiram, A., Fornasier, S., Le Du, M., ... & Zeganadin, D. (2021).
How to cite: Caminiti, E., Beck, P., Bonal, L., Schmitt, B., and Usui, T.: Low-temperature reflectance spectra of meteorites: implications for space missions, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-809, https://doi.org/10.5194/epsc-dps2025-809, 2025.
Introduction:
Studying Martian Meteorites in the laboratory provides fundamental clues about the surface composition as well as the evolution of Mars. Spectroscopic and geochemical investigations furnish valuable insight both regarding the planet composition and information related to secondary processes (i.e. aqueous alteration) [1,2] SNCs meteorites have compositions that are mafic to ultramafic [1,2] essentially basalts or basaltic cumulates. Spectroscopic investigations in the VIS-NIR moreover provide important laboratory data for comparison with rover missions that currently are exploring the Martian surface with in situ spectrometers at even higher spatial resolutions with respect to past instruments.
Here we present reflectance spectroscopic measurements on a large sample of Martian Shergottite, North West Africa (NWA) 13367, by using the VIS-IR hyperspectral imaging technique. The sample has been investigated in the range of 0.35-5.1 micron by means of the SPIM setup at IAPS-CLab [5,6].
Setup and sample description: the meteorite slab has been investigated with the Spectral Imager (SPIM) instrument in use at C-Lab laboratory at INAF-IAPS. The facility consists in an imaging spectrometer operative in the 0.35-5.1 micron-range [5,6], and contains the laboratory spare of VIR spectrometer onboard the Dawn mission [7]. The setup includes two bidimensional focal planes, a CCD (0.35-1 micron) and an HgCdTe (1-5.1 micron) detectors both hosted, together with the spectrometer, inside a liquid N2 cooled Thermal Vacuum Chamber. The entry slit is 9x0.038 mm corresponding to a single acquired image on the sample of 256 px, with spatial resolution of 38 micron/px on the target. The sample to analyze is placed outside the TVC on a 3-axis motorized stage: by moving the target at 38 micron-steps and acquiring consecutive frames it is possible to construct a hyperspectral cube of 876 spectral bands and the desired number of lines.
The analyzed sample is a slab of about 5x5 cm. According to the Meteoritical Bulletin, this sample is constituted mainly of olivine (50%), pyroxene (40%), and 5-10% maskelynite, and is characterized by ophitic/poikilitic texture. Pyroxenes range from a low Ca/Fe-rich pigeonite to a Ca-rich augite. Other phases include Fe-Ti oxides, sulfides, and merrillite (Ca-rich phosphate containing Na and Mg).
Measurements and Results: Two scans covering each an area of about 9x6 mm2 have been acquired on the same meteorite face. Each image has been constructed by acquiring 150 consecutive frames at 38-micron steps (dimension along the vertical axis). Here we focus on the first of the two scans. To obtain a first preliminary view of the spectral data, several band parameters maps have been retrieved. In particular, here we show the map of (i) band depth at 1 micron [Fig.1], and (ii) band depth at 0.65 micron [Fig.2]. The first map is related to the distribution of iron silicates (pyroxenes and olivine), and as can be seen, these phases cover the almost totality of the distribution map (Fig.1). Nevertheless most of the spectra resemble at first glance those of pyroxenes, characterized by the occurrence of the two Fe2+ bands at 1 and 2 micron (fig.3), with the second band varying between 2-2.3 micron.
Fig.1. Map of band depth at 1 mm for NWA 13367 cube, indicative of pyroxene/olivine distribution. This map and the following ones have dimensions of 9 mm x 5.7 mm.
In Fig.2 the distribution map of 0.65 micron band depth is shown. Although this absorption band could be consistent with spin-forbidden transition in Ti3+ in augite as reported in [8], here it appears, when present, broad and intense. Moreover, it seems to correlate with the 1-micron band more shifted towards longer wavelengths, pointing to a more Fe-rich composition. However it is evident how this phase forms outer rims (yellowish in this map) around core pyroxene grains with different composition (zonation) (Fig.2).
Fig.2. Map of band depth at 0.65 mm for NWA 13367 cube. This feature is related to Fe and/or Ti present in clinopyroxene.
A first tentative identification of spectral endmembers has been made by using the K-Means classification available on ENVI software. Spectral classes and relative representative endmembers are displayed in fig.3. Here spectra corresponding to pyroxene mineralogy are identified, with different levels of reflectance and also pyroxene composition, as suggested by the changing position of the 1 and 2-mm bands. The other two main classes identified likely represent a hydrated Fe-oxyde and a dark/opaque phase. In some locations spectra characterized by intense organic (C-H) features in the 3-4 micron region are identified (fig.4).
Fig.3. Spectral endmembers extracted as a first preliminary analysis through K-Means classification.
Fig.4. Selected spectra showing intense organic absorption features in the 3-4 micron region.
Conclusions and Future Work:
We started to investigate by means of VIS-IR imaging spectroscopy a Martian Shergottite (NWA 13367) at the spatial resolution of 38 mm. As preliminary spectral analysis, we retrieved several maps, for example at 1 micron (Fe silicates) and 0.65 micron (Ti or Fe-rich clinopyroxene). In particular, in some zones, the pyroxenes show zonation, with a likely Fe-rich outer rim. The correlation of 0.65-micron band depth with 1-micron band position will be further investigated. The 38-micron spatial resolution will allow to investigate in detail both the mineralogy of this sample and also at least some aspects related to the texture at the sub-mm scale. Moreover, additional analyses will be performed on a portion of this sample by means of coupled FTIR spectroscopy and mass spectrometry.
References: [1] Udry A. et al. JGR Planets 125 2020. [2] Treiman A H et al PSS, 48 1213 1230 2000 [3] Hicks L.J. et al. Geoc. Et Coscmoc. Acta, 136 194 210 2014. [4] Bishop J. L. et al. 80th Met. Soc. 6115 2017. [5] Coradini A. et al., Vol. 6, EPSC-DPS2011-1043, 2011. [6] De Angelis S. et al., Rev.Sci.Instr. 86, 093101, 2015. [7] De Sanctis M.C. et al., Space Sc. Rev., 163:329–369, 2011. [8] Klima R.L., et al., M&PS, 42, n.2, 235-253, 2007.
Acknowledgements: Scientific activities with SPIM are funded within the ExoMars program by the Italian Space Agency (ASI).
How to cite: De Angelis, S., Altieri, F., La Francesca, E., De Sanctis, M. C., Ferrari, M., Ammannito, E., Brossier, J., Bruschini, E., Formisano, M., Frigeri, A., and Trisic-Ponce, J.: Investigation of NWA13367 Martian Shergottite by means of VIS-IR imaging spectroscopy, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1700, https://doi.org/10.5194/epsc-dps2025-1700, 2025.
1. Introduction
The surfaces of many solar system airless bodies are covered by a layer of fine regolith formed by long-term space weathering processes, and traditional planetary remote sensing studies primarily focused on the research of optical properties of regolith layers. With the recent advances in space explorations, more disk-resolved spectral imagery data of the Moon, Mars, and asteroids have been returned and there is an increasing need to understand the reflectance properties of rocks and complex mixtures of rocks, fragments and powders (Pieters & Noble, 2016). The optical properties of rocks covered by fine dust layers can be very different from that of the layers and the underlying material (Kiddell et al. 2018; Johnson & Grundy, 2001; Johnson et al., 2002,). Therefore, it is important to understand the spectral, photometric and polarimetric properties of igneous rocks covered by powders with various thicknesses.
2. Samples and methods
We measured the reflectance of four igneous rocks (Trachyte, Peridotite, Diabase, Picrite Porphyrite, ranging from high to low reflectance) as bare slabs and slabs covered with powder layers of varying thicknesses (0.1 mm, 0.2 mm, 1 mm, and 2 mm) and particle sizes (0–45 µm, 90–125 µm).
We used two spectro-goniometric systems and one spectrometer to obtain the bidirectional reflectance spectra. CUG spectro-goniometric system: The emergence zenith angle varied from 0° to 70°, and the relative azimuth angle from 0° to 360° (Jiang et al., 2022). This configuration yields 121 viewing geometries for an incidence angle of 0° and 165 geometries for 55°. The spectral range covered is 0.35-2.1 µm. SHADOWS: We selected 15 specific wavelengths between 0.4 and 4.2 µm and collected 71 viewing geometries (Potin et al., 2018). SHINE spectrometer: This instrument measures spectra across a wavelength range of 0.35-4.2 µm with an incident angle of 30° and an emergency angle of 0° (Brissaud et al., 2004).
3. Result
Fig. 1 and Fig. 2 show the upper hemisphere reflectance and spectra of four rock slabs and the slab covered with varying powder layer thicknesses. The results demonstrate that rock slabs exhibit low reflectance and strong forward scattering, and even very thin dust layers (0.1mm) can significantly alter the overall reflectance and mask the strong forward scattering of rock slabs. Reflectance increases with powder thickness until reaching a "saturation thickness", after which further coating has little effect on reflectance spectra. Larger particles (90-125 µm) reach “saturation” faster than smaller ones (0-45 µm). Lower reflectance rocks and spectral regions are more susceptible to surface scattering effects than higher-reflectance rocks.
Fig. 3 displays the dependent of the phase angle on the spectral slope (0.6-1.8 µm) of the four rocks. It shows that rock slabs exhibit strong specular reflection and little phase reddening up in small phase angle, while powder-coated surfaces show a gradual and linear increase in spectral slope with phase angle. We analyzed the 2.7 µm hydration feature for Peridotite and the results show 2.7 µm hydration band decreases in strength with increasing phase angle and is weaker under strong specular reflection angle.
Using the Hapke two-layer model and Planet-GLLiM tool (Hapke, 2012; Douté et al., 2023), we retrieved the phase function parameters and optical constants of Peridotite, and reconstructed the spectra and bidirectional reflectance for bare and powder-coated slabs. Fig. 4 illustrates the dependence of reflectance on thickness, showing that reflectance increases exponentially with increasing optical thickness. We calculate the ratios of surface scattering to total scattering and retrieved the relationship of phase function parameters, indicate stronger surface scattering and forward scattering in bare rocks compared to powder-coated samples.
4. Conclusion:
We have measured the reflectance of four igneous rocks—Trachyte, Peridotite, Diabase, and Picrite Porphyrite—as bare slabs and as slabs coated with powder layers of four varying thicknesses and two particle sizes. We found that even very thin powder layers can significantly alter the reflectance and photometric behavior of rock surfaces. Reflectance increases with powder thickness until reaching a "saturation thickness", with larger particles reaching this threshold more quickly. And powder coatings reduce strong forward scattering. Bare rock slabs exhibit little phase reddening up in small phase angle, while powder-coated surfaces show a gradual and linear increase in spectral slope with phase angle. Modeling results reveal that reflectance grows exponentially with optical thickness, and that coated powder layers reduce surface scattering and weaken forward scattering behavior.
Fig. 1. Reflectance comparison of four rocks covered with different thicknesses of powder and bare rock slab. Purple: bare rock slab; Red: 0.1 mm powder layer coated; Orange: 0.2 mm; Blue: 1 mm; Dark blue: 2 mm.
Fig. 2. Reflectance spectra of the 4 igneous rocks and their powders in 2 size fractions. i = 0°, e = 30°.
Fig. 3. Phase angle dependent of the spectra l slope in the 0.6 to1.8 µm region of particle coated rock.
Fig. 4. The dependence of reflectance on optical thickness for Peridotite. (a) and (b) correspond to 0-45 µm size distribution, and (c) and (d) to 90-125 µm size distribution.
Reference:
Douté, S., Forbes, F., Borkowski, S., Heidmann, S. & Meyer, L. Massive analysis of multidimensional astrophysical data by inverse regression of physical models. (2023).
Hapke, B. Theory of Reflectance and Emittance Spectroscopy. (Cambridge University Press, 2012).
Johnson, J. R., Christensen, P. R. & Lucey, P. G. Dust coatings on basaltic rocks and implications for thermal infrared spectroscopy of Mars. J.‐Geophys.‐Res. 107, (2002).
Johnson, J. R. & Grundy, W. M. Visible/near‐infrared spectra and two‐layer modeling of palagonite‐coated basalts. Geophysical Research Letters 28, 2101–2104 (2001).
Jiang, T. et al. Bi-directional reflectance and polarization measurements of pulse-laser irradiated airless body analog materials. Icarus 331, 127–147 (2019).
Kiddell, C. B. et al. Spectral Reflectance of Powder Coatings on Carbonaceous Chondrite Slabs: Implications for Asteroid Regolith Observations. JGR Planets 123, 2803–2840 (2018).
Pieters, Carle M., and Sarah K. Noble. Space weathering on airless bodies. Journal of Geophysical Research: Planets 121.10 (2016): 1865-1884.
Potin, S. et al. SHADOWS: a spectro-gonio radiometer for bidirectional reflectance studies of dark meteorites and terrestrial analogs: design, calibrations, and performances on challenging surfaces. Appl. Opt. 57, 8279 (2018).
How to cite: Zhuang, Y., Zhang, H., Beck, P., Douté, S., Schmitt, B., and Liu, Y.: Effects of Powder Coatings on the Reflectance Spectra and Photometric Properties of Igneous Rocks, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1471, https://doi.org/10.5194/epsc-dps2025-1471, 2025.
Introduction: Samples collected by NASA’s Mars 2020 Perseverance rover that are intended for return to Earth would be analyzed based on the highest priority recommendations of the international science community. The samples collected at Jezero crater by Perseverance consist of a variety of rocks (e.g., sedimentary and volcanic), regolith, and atmospheric gas [1-4]. With each additional sample, the potential cache continues to become more scientifically valuable. Regardless of the additional samples, even the current suite of samples represents a scientifically return-worthy cache [5].
Before these precious samples are investigated in state-of-the-art laboratories on Earth, extensive testing of analogues is necessary to fully prepare for engineering, science, curation, and planetary protection needs. Therefore, multiple teams branching from the Mars Sample Return (MSR) Campaign Science Group (MCSG) have been chartered to strategically select natural samples from the field that best represent discrete components of the Jezero samples. Collectively, these samples make up the Analogue Sample Library (ASL), set up to support MSR, and jointly hosted by NASA and ESA. The ASL is designed to serve as a resource for preparations to receive and analyse returned samples and support the broader scientific community in research, communication and outreach. Samples in the ASL collection are curated at and distributed from the Natural History Museum in Oslo in collaboration with the University of Oslo (UiO). This activity is supported by the Norwegian Space Agency (NOSA) and ESA.
Current ASL Collection: In late 2022 an external expert science group, the ‘Rock Sample Team’ was appointed by the MSR Joint Science Office for various project needs. They were tasked to identify terrestrial analogue sites for four different lithologies based on the samples placed in the first sample depot on Mars at Three Forks.
These samples include (letters correlate to Fig. 1): (A) holocrystalline basalts, both aphyric and plagioclase-phyric, from Oregon, USA, (B) carbonate cemented and (C) carbonate-gypsum cemented fine sandstones/siltstones from California, and (D) eolian volcanic sands from Iceland, and (E) olivine cumulates from Scotland. The Rock Sample Team solicited input from the community and developed an extensive list of potential analogues before narrowing down to five candidates [6]. With field teams built from both NASA and ESA representatives, local geologists, as well as members from the Mars 2020 Science team, the first samples for the ASL were collected during the field campaign 2023 (Fig. 1).
Figure 1. Map displaying the sites of the field campaign 2023 (red stars) and newly proposed field sites (yellow stars; [7]). Pictures from the field teams of each field site are shown in inserts A-E.
Allocation of analogue samples: On November 14th, 2024, the ASL was officially opened at the Natural History Museum, Oslo. Analogue samples can be requested from the ASL. Proposals for allocation are evaluated according to priority of the proposed activity, which are (1) preparatory work for sample receiving, (2) the scientific community, and (3) public relations and outreach. The sample allocation process is managed by the NASA-ESA MSR Analogue Sample Allocation Panel (ASAP, Fig.2). Requests for analogue samples can be made via a web-interface (sample request) and are processed in a timely manner. The ASL also includes comprehensive baseline sample characterization by the Norwegian Geotechnical Institute (NGI), with reports available to the community.
Figure 2. Organizational flowchart for ASL sample management from collection and sample characterization to allocation and curation [6,7].
Ongoing and future work: The MCSG chartered a new sub-team, the MCSG Analogue Team, which is tasked to critically evaluate the current collection and identifying any areas that need to be supplemented. One of the first tasks of the Analogue Team was to reevaluate the sedimentary analogue samples and subsequently, two new field sites were identified in Italy and Iceland (Fig. 1) to collect (1) a sandstone with basaltic provenance and (2) sandstone to pebble conglomerates with an ultramafic provenance. These analogues will be collected during the 2025 field campaign, funded by ESA and NASA. Their addition to the ASL will make the analogue collection more comprehensive. The Analogue Team also plans to re-examine both the igneous and regolith sample analogs. Finally, the team plans to continuously build the ASL as the Perseverance rover continues to diversify its cache.
The ASL represents a key resource for the preparation to study returned samples from Mars, as it enables wide availability of terrestrial analogue samples that are strategically selected to best represent the properties of diverse Mars samples at Jezero crater and collected by the Perseverance Rover.
Acknowledgments: The authors would like to thank the members of the “Rock Sample Team” for their recommendations on terrestrial analogue sample. We also would like to thank the members of the field campaign 2023 for their effort to collect the analogue samples.
Disclaimer: The decision to implement Mars Sample Return will not be finalized until NASA’s completion of the National Environmental Policy Act (NEPA) process. This document is being made available for informational purposes only.
How to cite: Thiessen, F., Thorpe, M. T., Sefton-Nash, E., Harrington, A. D., Ciocco, M., Krzesinska, A., Werner, S., Griffiths, L., Mikesell, T. D., Smith, A. L., Hays, L. E., and Kminek, G.: Mars Analogue Sample Library, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-953, https://doi.org/10.5194/epsc-dps2025-953, 2025.
NASA-ESA Mars Analogue Sample Library (ASL) officially opened in 2024 at the Natural History Museum of Oslo. ASL aims to provide the scientific community with samples analogous to those sampled by Mars 2020 Perseverance in Jezero Crater during the Crater Floor and Delta Front campaigns. The goal is to prepare for operations and research relating to Mars, particularly on the eventually returned samples of Mars Sample Return[1], as well as outreach activities.
To assess analogue fidelity [2,3] tests are needed: among others, extensive mineralogical, petrological, chemical and mechanical characterization. Furthermore, in order to facilitate the comparison between the martian samples and the terrestrial analogues, characterization of the analogues via in-situ techniques used onboard Mars2020 is necessary. This study aims to analyze the ASL analogues with Raman Spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS). Raman spectroscopy, in particular, has been a crucial tool in the detection of many minerals on Mars [4], while LIBS gives a first order indication of the sample geochemistry.
ASL includes five sites with two representative samples of Jezero crater floor, one regolith analogue, and two samples aiming to represent the delta sediments [5,6, https://www.mn.uio.no/geo/english/research/projects/msr-asl-analogue-sample-library/msr-asl/].
Olivine cumulates from the Isle of Rum (Scotland) share similarities with cumulates found in Séítah formation and corresponding Robine, Malay, Salette and Coulettes samples. Aphyric (HMA) and phyric (HMP) holocrystalline basalts from Hart Mountain (HM), Oregon, USA, are the selected analogues for Máaz formation (samples Montdenier, Montagnac, Ha'ahóni, Atsá). Basaltic lithic sand from Lambahraun (Iceland) is intended to emulate Martian regolith (samples Atmo Mountain and Crosswind Lake). Finally, sandstones were sampled at Salton Sea and Ridge Basin (California) in order to represent the Delta Front Skinner Ridge, Wildcat Ridge and Amalik formations (samples Hazeltop, Bearwallow, Skyland, Swift Run, Shuyak and Mageik).
SimulCam, the heavy-duty laboratory emulator supporting SuperCam science [7], has been used to collect coaligned, time-resolved Raman and LIBS analyses from ~3-5 cm bulk samples. For each sample, 5–10 spots have been analyzed at 2m distance to disclose the mineralogical and geochemical complexity of the materials. Additionally, thin sections have been prepared for EDX mapping to provide laboratory ground-truth for observations made by Raman and LIBS. These measurements complement the baseline laboratory characterisation, which includes X-ray diffraction, X-ray fluorescence, and measurements of calcium carbonate content, particle size distribution and shape.
In Rum, olivine is abundant, as in Séítah, evidenced by Raman spectrometry (Fig. 1): the distinct olivine doublet peak correlates with the Raman spectrum acquired by SuperCam on Dourbes. Furthemore, the olivines appear to chemically match estimations of the forsterite% for Séítah samples Salette and Coulettes [8], but look partially serpentinized, whereas no serpentine was detected in Séítah. Carbonates, widespread in Séítah, appear as up to 10% in Rum. Rum is a good textural analogue to Séítah, with olivine grains of the same size (1-3 mm) and similar poikilitic texture.
As a representative case study, spectroscopic analyses of Rum performed by SimulCam revealed elemental and molecular compositions similar to those of targets investigated by SuperCam at Séítah. In this context, the combined interpretation of LIBS and Raman features could be employed to develop and test methods for quantifying fayalite–forsterite ratios in olivines, a key focus of the ongoing work by the SuperCam science team.
Figure 1: Séítah Raman spectra at Dourbes abrasion patch in Brac outcrop (top), and Simulcam spectra of Rum (bottom), indicating the presence of the typical olivine doublet peaks (shaded area).
Basalts from Hart Mountain (Máaz analogues), are composed of plagioclase and pyroxene. Texturally, HMA samples are representative of the samples Montdenier and Montagnac. HMP presents a larger porphyric texture, though the plagioclase crystals are one order of magnitude too large compared to Ha'ahóni and Atsá.
Lambahraun sand is composed of basaltic grains close in size and composition to what has been observed in Crosswind Lake and Atmo Mountain. In particular, one of the aims of sampling a megaripple was to sample the <150 micron size range [9] to characterize the global regolith of Mars. Such small particles appear to constitute >20% of Lambahraun samples, making it a good engineering analogue. It is well-sorted, rather coincident with the moderately to well-sorted martian samples. Their grain shape is consistent both in sphericity and roundness.
The sandstones analogous to Delta Front rocks contain carbonate and/or sulfate cement in varying amounts, but their clastic material is predominantly quartz and feldspars, unlike basaltic grains on Mars. Texturally, Ridge Basin can be analogous to the well-sorted material of Shuyak and Mageik, as well as the carbonate-rich laminations of Skyland and Swift Run. Salton Sea appears richer in sulfates, while still containing carbonates, making its cement analogous to Bearwallow and Hazeltop cores.
ASL analogues are extensively tested to evaluate their relevance to mission science preparations. While laboratory analyses provide ground-truth characterization of the analogue material, evaluation of the analogues with SimulCam allows more direct comparison with data collected in situ on Mars. Furthermore, such results combined with extensive ongoing characterization of analogues via laboratory techniques can support interpretation of martian formations, as the results highlight capabilities and limitations of the Perseverance instruments in detecting and characterizing mineralogical and geochemical details of encountered rocks.
Disclaimer: The decision to implement Mars Sample Return will not be finalized until NASA’s completion of the National Environmental Policy Act (NEPA) process. This document is being made available for informational purposes only.
Acknowledgments: Curation of Mars ASL is financed by ESA and NoSA (PRODEX) project.
References: [1] Tait. K. et al. (2022) Astrobiology 22(S1), S-57 [2] Foucher F. et al. (2021) Planetary and Space Science, 197, 105162. [3] Thorpe M. T. et al. (2025) LPI Contributions, Abstract #2109. [4] Lopez-Reyes, G. et al. (2025) Authorea Preprints, ESS Open Archive [5]Thiessen F. et al. (2024) LPI Contributions 3036, Abstract #6173. [6] Thiessen F. et al. (2025) EPSC-DPS2025-953 [7] Manrique J. et al (2024) Advances in Space Research, 74(8), 3855-3876 [8] Beyssac O. et al (2023) Journal of Geophysical Research: Planets 128 (7), e2022JE007638 [9] Hausrath E. M. et al. (2025) Journal of Geophysical Research: Planets, 130(2), e2023JE008046.
How to cite: Ciocco, M., Krzesinska, A., Werner, S. C., Müller, A. B., Julve-Gonzalez, S., Veneranda, M., Lopez-Reyes, G., Thiessen, F., Sefton-Nash, E., Mikesell, T. D., and Griffiths, L.: Three Forks Depot Analogues in Mars Analogue Sample Library – Representativity Assessment via Raman and LIBS Spectroscopy , EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1445, https://doi.org/10.5194/epsc-dps2025-1445, 2025.
Introduction
Mercury, the closest planet to the Sun, has been studied by two NASA missions: Mariner 10 and MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging). They provided much information about the surface of the planet including the unique surface composition—characterized by a strong depletion in iron for example—and the identification of distinct regions with varying chemical compositions. However, one remaining question about Mercury is the mineralogical composition of its surface. Visible to near-infrared observations from the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) aboard MESSENGER lack absorption features of mafic minerals. One hypothesis for the absence of spectral signatures typically associated with mafic minerals is the low abundance of FeO [1]. Furthermore, Mercury's complex geological history, involving extensive volcanic activity, impact melting, and intense space weathering, likely resulted in the production of substantial amounts of glass at the surface, which may significantly influence the planet's spectral properties [2]. The ESA’s BepiColombo mission, launched in 2018, will soon be in its polar orbit around Mercury. Two key instruments will help characterize the surface mineralogy of the planet: MERTIS (Mercury radiometer and thermal infrared spectrometer), a radiometer and thermal infrared spectrometer operating between 7 and 14 µm and SIMBIO-SYS (Spectrometers and Imagers for MPO BepiColombo Integrated Observatory System), a high-resolution camera, a stereo camera and a near infrared hyperspectral imager operating between 0.4 and 2 µm. The aim of this study is to spectrally characterize glassy synthetic analogs with compositions similar to the five main geochemical regions of Mercury. This work is done at the Planetary Spectroscopy Laboratory (PSL) of the German Aerospace Center (DLR), Berlin. The spectral measurements will be compared to MASCS data and used for the interpretation of SIMBIO-SYS and MERTIS data. Thus, it will be possible to identify the effect of volcanic glass and their specific compositions characterized by a range of MgO content and low FeO.
Samples
The samples used in this study have been synthesized at the University of Liège by mixing high purity oxides and melting them in a Platinum crucible at 1500°C for 1 hour. The silicate melts were quenched in water to produce glass beads, similar to the volcanic glass expected on Mercury. The compositions are analogs to five hermean regions [3]: the Low-Mg Northern Volcanic Plains (Low-Mg-NVP), the High-Mg Northern Volcanic Plains (High-Mg NVP), the Smooth Plains, High-Mg Province and the Intermediate Terrains (ICP-HCT). The geochemical compositions of the samples are given in Table 1. In order to investigate the effect of glass particle size, each sample has been crushed in two different grain sizes: <125 µm and 125-250 µm, thus a total of 10 samples have been measured.
Table 1: Selected chemical compositions of glassy analogues (in wt%) [3].
|
Region |
SiO2 |
Al2O3 |
MgO |
CaO |
Na2O |
Total |
|
Low-Mg NVP |
63.36 |
14.40 |
10.21 |
5.78 |
6.25 |
100.00 |
|
Smooth Plains |
59.90 |
16.03 |
11.40 |
7.35 |
5.32 |
100.00 |
|
High-Mg NVP |
60.43 |
12.31 |
16.89 |
6.44 |
3.92 |
99.99 |
|
ICT HCT |
55.76 |
12.70 |
21.73 |
5.70 |
4.11 |
100.00 |
|
High-Mg Province |
55.82 |
7.05 |
26.80 |
7.14 |
3.19 |
100.00 |
Experimental procedure
Firstly, the bidirectional reflectance of the samples has been measured in a range of ultraviolet (UV) to the mid-infrared (MIR) to cover the wavelength domains of MESSENGER’s (0.3 to 1.45 µm) and BepiColombo’s instruments (0.4 to 2 µm and 7 to 14 µm). Several illumination conditions and viewing geometries have been used to obtain bidirectional reflectance spectra in the same conditions of MASCS and SIMBIO-SYS observations. The reflectance measurements were supplemented with hemispherical reflectance data acquired in the MIR domain. Then, the samples have been heated up at temperatures from 250°C to 450°C to simulate the surface temperature of Mercury, and measure the emissivity every 50°C in the MIR - spectral range of the MERTIS instrument. After heating the samples, reflectance measurements in the UV to MIR were acquired again, to investigate the effect of the heating at Mercury’s day-side temperature. All the measurements have been performed under vacuum to simulate Mercury’s surface conditions.
Preliminary results
After calibrating and merging the different wavelengths for the bidirectional reflectance, we obtained the spectra shown in Figure 1. A decrease of reflectance is visible when the phase angle increases before and after heating. After heating, the sample ICP-HCT shows an increase of the reflectance in the visible to NIR and a decrease of the hemispherical reflectance in the MIR spectral domain. In the MIR, the sample exhibits a strong Christiansen Feature (CF) - reflectance minimum - at around 8.25 µm. Calibration and processing of the emissivity measurement data are currently in progress.
Figure 1 : (a) Bidirectional reflectance of ICP-HCT (125-250 µm) before heating (solid line) and after heating (dashed line) at 3 different geometries in the UV, visible and near-infrared. (b) Hemispherical reflectance of the same sample before and after heating in the MIR spectral domain.
Conclusion
In this study we measured unique samples simulating volcanic glass of different geochemical regions of Mercury. We obtained the reflectance of the samples before and after heating at Mercury’s day-side temperature, through different illumination and viewing geometries, in a wavelength range covering the range of both MESSENGER’s and BepiColombo’s instruments. Emissivity spectra were also completed while heating the samples to simulate the temperature of Mercury’s surface.The measurements will be compared to MASCS/MESSENGER observations and will be used for the interpretation of SIMBIO-SYS and MERTIS observations by the BepiColombo spacecraft.
References
1. Murchie, S. L., et al. (2015). Icarus, 254, 287-305.
2. Pisello, A., et al. (2022). Icarus, 388, 115222.
3. Namur, O. & Charlier, B. Nat. Geosci. 10, 9–13 (2017).
How to cite: Gaudart, B., Barraud, O., Charlier, B., Namur, O., Lamers, G., Maturilli, A., and Adeli, S.: Spectral analysis of silicate glasses analog of Mercury’s geochemical terrains and comparison with MESSENGER and BepiColombo data, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1534, https://doi.org/10.5194/epsc-dps2025-1534, 2025.
Many celestial bodies in our Solar System, such as the Moon, Mars and small bodies, are covered with a layer of regolith. Numerous current and upcoming space missions aim to interact with these surfaces such as the IDEFIX rover of the Martian Moons eXploration (MMX) mission [1] and the Hera mission [2]. Some instruments, such as the instrument InSight HP³ mole, have even failed to perform as expected [3], highlighting the importance of understanding the geotechnical behavior of regolith surfaces. Due to the limited accessibility and high cost of in situ missions, laboratory experiments using regolith simulants are crucial for the preparation of surface operations like landing, mobility, and sampling. Different extraterrestrials simulants have been developed and characterized regarding the mineralogical, granulometric and some geotechnical properties [e.g., 4-7]. Here we present the results of additional characterisation experiments focussing on the dynamic angle of repose and the cohesive properties of the simulants. A rotating drum experiment has been developed to measure bulk properties of different planetary simulants in low consolidation conditions. The setup is presented in Figure 1. The simulant is placed in a cylinder container of 4 cm diameter and 5 cm depth so that the container is half full with the granular material. Two PMMA windows are mounted on the front and back of the container, to be able to see through the system. The sample container is attached to a drive shaft which allows it to rotate around its axis. A CCD camera (mvBlueFox-120aG) is fixed facing the front window to image the granular material. An LED panel illuminates the experiment from behind allowing a shadometry image analysis to be performed. The rotational speed of the motor is controlled by an Arduino card. The gear ratio between the motor and the container allows it to rotate between 10 and 70 rotations per minute (RPM).
Figure 1: The rotating drum experiment at ISAE-SUPAERO.
The motor rotational speed is varied and 10 images are taken for each speed with a frame rate of 20 Hz. A binarization of the image is performed followed by an edge detection which automatically detects the surface of the material. This process is shown in Figure 2 for glass beads at two different rotational speeds. It is performed on the 10 images, and for each rotational speed, as illustrated in Figure 3.
Figure 2: Surface detection for glass beads at two different rotational speeds.
Figure 3: Surface profiles for 10 images at different rotational speeds for glass beads.
By measuring the surface slope close to the center of the drum, the dynamic angle of repose for each rotational speed can be determined. This result is presented in Figure 4 for three different granular materials: quartz sand with a mean particle diameter of 500 µm, glass beads with a diameter between 90 and 150 µm and Mars Global (MGS-1) High-Fidelity Martian Regolith Simulant.
Figure 4: Dynamic angle of repose as a function of the rotational speed. The error bars represent the standard deviation of the angle of repose measured in 10 different images at each rotation speed.
This experimental set-up also allows for a characterisation of the cohesive properties of the granular material. The rugosity of the surface at each rotational speed can be used to compute the cohesive index, an adimensional number directly linked to the total cohesive force [8]. This gives a comparative measurement of the cohesion of the different simulants.
In summary, we have developed a rotating drum experiment to characterise different planetary simulants. Two main material parameters can be extracted: a cohesive index, which is an adimensional number directly linked to the total cohesive forces, and the dynamic angle of repose. The set-up has already been tested with three different materials (glass beads, quartz sand and Mars Global (MGS-1) High-Fidelity Martian Regolith Simulant). The results of the rotating drum characterisation of the Exolith planetary simulants - Lunar Highlands (LHS-1) High-Fidelity Regolith Simulant, Lunar Mare (LMS-1) High-Fidelity Regolith Simulant, Carbonaceous Chondrite (CI-E) High-Fidelity Asteroid Regolith Simulant and Carbonaceous Chondrite (CM-E) High-Fidelity Asteroid Regolith Simulant - will be presented during the conference.
References:
[1] Michel, Patrick, et al. "The MMX rover: performing in situ surface investigations on Phobos." earth, planets and space 74 (2022): 1-14.
[2] Michel, Patrick et al. (2022). The ESA Hera mission: Detailed Characterization of the DART Impact Outcome and the Binary Asteroid (65803) Didymos. The Planetary Science Journal, 3:160.
[3] Spohn, Tilman, et al. "The InSight-HP3 mole on Mars: Lessons learned from attempts to penetrate to depth in the Martian soil." Advances in Space Research 69.8 (2022): 3140-3163.
[4] Long-Fox, Jared M., et al. "Geomechanical properties of lunar regolith simulants LHS-1 and LMS-1." Advances in Space Research 71.12 (2023): 5400-5412
[5] Cannon, Kevin M., et al. "Mars global simulant MGS-1: A Rocknest-based open standard for basaltic martian regolith simulants." Icarus 317 (2019): 470-478
[6] Yin et al., “Shear Properties of LHS-1 and LMS-1 Lunar Regolith Simulants”. Planetary and Space Science 2023, 226, 105630. https://doi.org/10.1016/j.pss.2022.105630.
[7] Just, G. H.et al., “Geotechnical Characterisation of Two New Low-Fidelity Lunar Regolith Analogues (UoM-B and UoM-W) for Use in Large-Scale Engineering Experiments”. Acta Astronautica 2020, 173, 414–424. https://doi.org/10.1016/j.actaastro.2020.04.025.
[8] Neveu, A., F. Francqui, and Geoffroy Lumay. "Measuring powder flow properties in a rotating drum." Measurement 200 (2022): 111548
Acknowledgements
This project is carried out with the support of the European Research Council (ERC) GRAVITE project (Grant Agreement N°1087060), and from CNES in the context of the Hera mission and the MMX rover/wheelcams.
How to cite: Amsili, A., Murdoch, N., Delton, P., and Da Silva Alves, C.: Characterisation of planetary simulants using a rotating drum experiment, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-671, https://doi.org/10.5194/epsc-dps2025-671, 2025.
Introduction
A good understanding of the properties of water-ice and regolith mixtures is of paramount importance to support the development of upcoming scientific missions to the Moon and for future in-situ resource utilization (ISRU). Although water was already detected on the Moon by remote sensing observations and in impact ejecta (Colaprete et al. 2010), ground truth based on in-situ measurements is still missing. Water is a valuable resource for both human and robotic space exploration as it can be used as a propellant to fuel rockets or consumable for astronauts. Here, we present the development of a dusty thermal vacuum chamber (DTVC) at the Technical University of Munich (TUM) that will be used to qualify instrumentation developed for future Moon missions and to thermal ice extraction in relevant environments ( mbar, 150K).
Experiment Description
The state-of-the-art facility can reach vacuum levels down to mbar. To prevent sublimation of ice particles, the regolith sample is cooled by a laboratory thermostat to a minimum temperature of 150 K. The cold plate can host a variety of sample geometries up to a size of 590 mm x 240 mm x150 mm (Figure 1). As the cooling system does not rely on consumables like liquid Nitrogen, the sample cooling can theoretically be sustained for several days.
Figure 1: The cold plate of the experiment with different regolith containers.
The samples can be illuminated by a calibrated halogen lamp with a light power of up to 50 W in the visible range. The position of the collimated light beam (Ø 50mm) is controlled by a movable mirror (see Figure 2). This allows for a maximum illuminated sample region with a diameter of 275 mm. The resulting temperature distribution in the sample is measured by sensors inside the sample as well as an infrared camera.
Figure 2: Overview of the vacuum chamber with illumination (marked in red) and ice retrieval (marked in pink) sections. A zoomed view on the mirror assembly indicates the position control of the mirror.
Planned Experimental Campaigns
In the near future, several novel experiments are planned to use this DTVC setup:
Investigation of Solar Heating for Thermal Ice Extraction:
As part of the EIC pathfinder project Ice2Thrust, this experiment will study the heat distribution in response to solar surface heating and the interaction of water vapor with a cold trap in close vicinity to the surface. The illumination can provide light power up to 20 solar constants, which allows an investigation of various surface power densities on the temperature distribution and water sublimation rates. A separate assembly is mounted on the side of the main chamber to retrieve the ice collected on the cold plate with a linear feed-through. It can be isolated with gate valves, allowing the pressurization and subsequent liquefaction of the collected water ice. The extracted liquid water will be fed to an electrolyser and subsequently be split into Hydrogen and Oxygen to generate thrust in a chemical thruster. This experiment will serve as the world’s first ISRU end-to-end demonstration from extraction up to utilization.
Qualification of Sensors for Water Ice Detection on the Moon:
TUM is developing several permittivity sensor for the detection of water on the lunar surface. These sensors measure the water content by detecting changes in the electric permittivity of the lunar surface via electrodes in direct contact with the soil (Gscheidle et al. 2024). The RPS sensor suite currently developed for ESA uses electrodes mounted on a rover wheel and will undergo development and qualification testing in the DTVC. As part of another development for ESA, an instrumented drill for volatiles and water ice prospecting will also be tested in the DTVC (Biswas et al. 2020).
As the interaction of ice, rocks, and sunlight is also relevant in cometary research (Kreuzig et al. 2021, Knoop et al. 2024), the DTVC facility can also be used to study related physical phenomena relevant to other icy moons and comets.
Investigation and Development of Dust-resistant Mechanisms:
Lunar and planetary regolith are composed of abrasive particles in several size ranges which can significantly impact the lifetime of space mechanisms. Qualification and test of mechanisms in a relevant environment is crucial to ensure proper lifetime on the lunar surface. The DTVC offers this test capability and will also be used to qualify a newly developed slip ring within the RPS project funded by ESA (Sesko et al., 2025).
Conclusion
The DTVC facility is crucial for advancing lunar exploration and ISRU in ongoing research projects. By enabling experiments on water-ice and regolith mixtures, it supports the development of key technologies for detecting lunar water, thermal ice extraction, and durable instrument components. These efforts are essential for the success of future lunar and planetary science missions and developments leading to the utilization of lunar resources.
References
Colaprete, A., et al. (2010). Detection of Water in the LCROSS Ejecta Plume. In Science (Vol. 330, Issue 6003, pp. 463–468). American Association for the Advancement of Science (AAAS). https://doi.org/10.1126/science.1186986
Kreuzig, C., et al. (2021). The CoPhyLab comet-simulation chamber. In Review of Scientific Instruments (Vol. 92, Issue 11). AIP Publishing. https://doi.org/10.1063/5.0057030
Knoop, C., et al. (2024). Experimental results from the CoPhyLab -Detection of the influences of surface structureson particle ejection in comet-simulationexperiments. Copernicus GmbH. https://doi.org/10.5194/epsc2024-499
Sesko, R., et al. (2025) A dust-tolerant slip ring for Lunar rover wheel-mounted permittivity sensors, accepted talk at European Space Mechanisms and Tribology Symposium, Lausanne, Switzerland
Biswas, J., et al. (2020). Searching for potential ice-rich mining sites on the Moon with the Lunar Volatiles Scout. In Planetary and Space Science (Vol. 181, p. 104826). Elsevier BV. https://doi.org/10.1016/j.pss.2019.104826
Gscheidle, C., et al. (2024). Permittivity sensor development for lunar and planetary surface exploration. In Frontiers in Space Technologies (Vol. 4). Frontiers Media SA. https://doi.org/10.3389/frspt.2023.1303180
Acknowledgements
The authors gratefully acknowledge the financial support of the European Union (GA number 101161690) for the project Ice2Thrust (S4I2T)
How to cite: Witzel, T., Šeško, R., and Reiss, P.: Experimental Investigation of Regolith-Ice Mixtures under Cryogenic Vacuum Conditions for Lunar and Planetary Exploration, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1244, https://doi.org/10.5194/epsc-dps2025-1244, 2025.
Introduction
The Ion and Energetic Neutral Atom (I-ENA) beam facility at INAF-IAPS provides a unique platform to investigate the interaction of modifiable ion and neutral beams with a wide range of samples and detectors [1, 2]. For over two decades, this facility has supported studies on the interaction of the solar wind with planetary environments, with particular emphasis on ENA detection and charge exchange processes. Recently, the scientific focus has been related to backscattered and sputtered particle yields, as well as exosphere refilling processes [3, 4]. These efforts have contributed to the characterisation, testing, and calibration of the SERENA particle packed of the cornerstone space mission, BepiColombo, to Mercury [5]. Today, the I-ENA facility supports active space missions (e.g., BepiColombo/SERENA/ELENA), early-phase instrument developments (e.g., SWEATERS [6]), and testing campaigns for materials, detectors, and subsystems, particularly in the context of low-energy (0.5–5 keV) interaction processes.
I-ENA facility
The I-ENA laboratory includes two high vacuum chambers (10-7 mbar), each with a respective ion source. The first chamber is equipped with a He+/Ar ion source (Penning-type cold cathode) with an energy range of 0.5-5 keV, and is capable of producing fluences of 1014 ions/cm2 over a 12 hr irradiation period. This source can be modulated in intensity using various pinholes and an Einzel lens system. ENAs may be generated using a charge exchange cell. Within the chamber, there is a translation-rotation stage, to move samples horizontally, vertically, and rotate them through 360°. This chamber is currently equipped with a Quadrupole Mass Spectrometer (QMS), with a mass range up to 200 u and a sensitivity down to partial pressures of 10-14 mbar. The QMS is used for residual gas measurements and to investigate volatile species within the chamber. An image and schematic of this chamber is shown in Figure 1.
Figure 1. One of the I-ENA high vacuum chambers, and schematic of the set up.
The second, newest chamber hosts a higher intensity He+/Ar source, capable of producing beams with fluences of 1018 ions/cm2 over a 12 hr irradiation period. Consequently, this beam is more suited to experiments requiring higher fluences to replicate geological timescales on planetary bodies. The chamber is also within a clean (ISO 7) environment, suitable for testing instrumentation for space applications.
Experiments
The I-ENA laboratory facilitates calibrations of particle detectors and controlled experiments using ion/neutral beams to irradiate diverse surface analogues for investigating planetary space weather. A core activity of the lab has been the development and testing of space instrumentation. Notably, ELENA (Emitted Low-Energy and Neutral Atoms), part of the SERENA suite onboard BepiColombo, was developed, tested, and calibrated at I-ENA and the University of Bern. ELENA detects backscattered ENAs as well as magnetospheric and solar wind ions in the 10 eV–5 keV energy range. The ELENA Flight Spare (FS) is still housed in the lab and will be used in upcoming experiments to investigate ion-surface interactions with Mercury analogues. These studies aim to provide ground truth for interpreting data collected by BepiColombo.
The I-ENA lab team is currently expanding its capabilities to establish an irradiation facility for analogue testing. These experiments are designed to investigate irradiation-driven processes, building on our expertise in planetary space weather. By collaborating with external facilities that specialise in sample analysis, we aim to study the coupled exosphere–magnetosphere–surface system as a whole. Current experiments include collaborations within INAF, for example irradiating the enstatite achondrite meteorite, NWA 13278, using a He beam of 4.5 keV to simulate the solar wind irradiating Mercury’s surface. Full details of this experiment can be found in the abstract in this session (Galiano, A., et al. (2025). Space weathering simulation on the Aubrite meteorite NWA 13278, putative analogue of Mercury. EPSC-DPS Joint Meeting 2025). Current work involves investigating release processes on different materials using the QMS, and using the ELENA FS to investigate backscattering processes of the solar wind, in collaboration with other BepiColombo teams [7].
Acknowledgements: This Activity is supported by ASI contract SERENA/BepiColombo Fase E.
References
[1] De Angelis, E., et al. (2009). A facility to study the particles released by ion-sputtering process. European Planetary Science Congress (EPSC), Potsdam.
[2] De Angelis, E., et al. (2024). Accelerated ion-ENA beam for planetary space weather. Congresso Nazionale di Scienze Planetarie (CNSP), Bormio.
[3] Milillo, A., et al. (2005). Surface-Exosphere-Magnetosphere System of Mercury. Space Science Reviews, 117, 397–443. https://doi.org/10.1007/s11214-005-3593-z
[4] Mura, A., et al. (2006). Neutral Atom Emission from Mercury. Advances in Geosciences, 3. https://doi.org/10.1142/5913-vol3
[5] Orsini, S., et al. (2021). SERENA: Particle Instrument Suite for Determining the Sun–Mercury Interaction from BepiColombo. Space Science Reviews, 217, 19. https://doi.org/10.1007/s11214-021-00801-9
[6] De Angelis, E., et al. (2022). An innovative ENA instrument for space weather monitoring: SWEATERS (Space WEATher ENA Radiation Sensors) project. 44th COSPAR Scientific Assembly.
[7] Barraud, O., et al. (2025). Mercury-Y Lab: A scientific rehearsal for future BepiColombo observations. Lunar and Planetary Science Conference (LPSC).
How to cite: Richards, G., Brin, A., De Angelis, E., Rispoli, R., Moroni, M., Sordini, R., Colasanti, L., Vertolli, N., Nuccilli, F., Milillo, A., Mura, A., Orsini, S., Massetti, S., and Leto, C.: Planetary space weather experiments at the I-ENA facility at INAF-IAPS in Rome, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1298, https://doi.org/10.5194/epsc-dps2025-1298, 2025.
Abstract
This unique and now improved planetary simulation facility is capable of re-creating extreme Terrestrial, Martian and now Lunar-like environments. It has been supported by various EU networking activities including Europlanet 2024 RI and continuing through the Europlanet Society. This facility is also used by ESA and NASA and has recently become an ESA Ground Based Facility making it possible to apply for funding from ESA to access this facility for Space related research projects (up to 50keuros) [1].
1 Europlanet Transnational Access
This environmental simulator facility is utilized for a broad range of research programs including; the study of other planets (such as Mars), for recreating extreme terrestrial environments, or in specific investigations involving aerosols and other forms of Aeolian particulate transport. The facility has been involved in the Europlanet 2024 Research Infrastructure through which a trans-national access program has allowed numerous research groups access to this facility. Some selected recent projects are listed below;
- Sand transport and ripples on Mars [3,7]
- Dust aerosols at low pressure. [2,6]
- Polar CO2 ice on Mars (USA) [5]
- LIBS system on Mars2020 (ISAE France) [4]
- In-situ utilization on Mars2020 and dust loading. Imperial College UK [8]
These activities continue through the Europlanet Society pilot trans-national access scheme.
Other activities include the development, testing and calibration of sensor and planetary lander systems, both for ESA and NASA. Testing for missions ExoMars 2020 and Mars Perseverance were carried out.
Figure 1 The main Planetary Simulation Facility [1-8], guests carrying out a Europlanet2022RI funded experiment involving sand transport under Martian and terrestrial conditions [3] 2022.
2 Design and operation
The simulator consists of a 35m3 environmental (thermal-vacuum) chamber within which a re-circulating wind tunnel is housed. The wind is generated by a set of two fans which draw flow down the 2m×1m tunnel section and return it above and below. Wind speeds in the range 1-40 m/s have been demonstrated. Cooling is achieved by a novel liquid nitrogen flow system which has achieved temperatures below -160ºC. The inner chamber is thermally isolated from the vacuum chamber. An atmospheric cooling system allowing independent control of the air temperature (tested to -50°C) and a range of particle imaging, microscopy and laser based techniques allow study of aerosols [2].
Recent Improvements: Major recent improvements to the facility (funded by Europlanet 2024RI) include; an additional Roots and turbo-pump system allowing pressures below 10-4 mbar to be achieved (important for lunar simulation). An additional test section has been constructed, dedicated to lunar/icy-moon simulations. An advanced cooling/heating element has been constructed funded by ESA and improved aerosolization systems for dust and ice studies. Additional recent sensor systems include a new Laser Doppler Velocimeter system, a unique optical transmission (opacity) sensor array for studying sand/aerosol properties and a prototype flow sensor array (micro- Pitot tubes) [2,8].
Figure 2 Additional pump system (left) and a new test section (right)
Lunar simulation: Although the pressure achievable at this facility (10-4mbar) is far larger than that of the lunar surface, for dust transport / exposure research (or testing) it is sufficient that dust grain trajectories are unaffected by drag i.e. the scattering length is larger than the size of the chamber. The large volume of this chamber also allows relatively large scale regolith simulation. This could for example aid in development/testing of in-situ resource utilization technologies.
Figure 3 studying resuspended dust using prototype a light transmission (opacity) system and micro-Pitot tube wind flow sensors [8].
3 Sand, dust and ices on Mars
With control of wind flow at low pressure and temperature this facility is well suited for recreating the environment at the surfaces of terrestrial type planets such as Mars, Earth and icy moons. The interaction of wind and the planetary surface, specifically the transport of sand and dust is fundamental to understanding the evolution of the planets’ surface and atmosphere. Laboratory studies of the entrainment, flow, deposition and erosion are scarce and empirical in nature. The effects of low atmospheric pressure, composition, temperature can now be studied in detail.
This laboratory has been part of an EU supported European collaboration called ROADMAP including groups from BIRA in Belgium, CSIC in Spain and UDE in Germany, to study dust aerosols on Mars [Home (aeronomie.be)].
4 Conclusion
This planetary simulation facility has many unique and recently improved features which make it well suited for both planetary research applications and the development/testing of instrumentation. Details of some of the most recent and upcoming collaborative research activities will be summarized. For information on access to this facility please contact the author.
Acknowledgements
This laboratory is a member of Europlanet 2024 RI which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149.
The laboratory is also a member of the ROADMAP project which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004052.
References
[1]https://scispace.esa.int/scispace-platforms/ground-based-facility-gbf/
[2]A. Waza et al., (2023) PSS 227, 105638.
[3]Yizhaq, H., et al., Nat. Geosci. 17, 66–72 (2024)
[4] Murdoch, N., et al., PSS, 165 (2019) 260-271
[5] G. Portyankina et al., Icarus 322, 210–220 (2019)
[6] E. del Bello, et al., Scientific Reports, 8, 14509 (2018)
[7] Andreotti and Claudin et al.. PNAS 5, 118 (2021)
[8]K.R.Rasmussen et al., Flow Measurement and Instrumentation 101C (2025) 102750.
How to cite: Merrison, J., Iversen, J. J., and Rasmussen, K.: A European Planetary and Lunar Simulation Facility, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-293, https://doi.org/10.5194/epsc-dps2025-293, 2025.
Microgravity platforms such as drop towers [1], sounding rockets, the International Space Station (ISS), and parabolic flights offer varying levels of low gravity conditions, typically ranging from 10-4 – 10-6g, where g represents Earth’s gravitational acceleration. Certain platforms—such as Blue Origin’s suborbital rocket system—are also able to recreate partial gravity environments, enabling experiments under conditions that replicate e.g., lunar gravity. Partial gravity can also be generated during specific parabolic flight maneuvers [2], or using small centrifuges placed within microgravity platforms [3]. The 40-meter Einstein Elevator, for example, can support large-scale experiments (up to 1.7 meters in diameter) under partial gravity, but only down to 0.1g [4,5]. Similarly, the 16-meter ZARM GraviTower Pro [6] offers both lunar (1/6 g) and Martian (1/3 g) gravity conditions, as well as microgravity. However, this facility presently lacks the capability to produce intermediate levels of partial gravity.
We are currently building a new variable gravity laboratory at ISAE-SUPAERO that is complementary to these existing facilities. The facility will be capable of providing a wide range of gravity conditions (0.3 – 10-3g) for short duration (~0.7 s), large-scale (~0.9 x 1.5 m) experiments under vacuum conditions. The experience gained during the development and operation of an Atwood machine for creating partial gravity conditions [7-9], contributed significantly to our understanding of the design challenges for such a facility and the improvements that are necessary to increase the performance of the new variable gravity laboratory. The new variable gravity facility is currently under development and the first scientific experiments are expected to be performed early 2026.
Figure 1: The variable gravity laboratory and its cradle. The tower is 7m high.
The core principle of the variable gravity laboratory involves a vertically moving cradle inside a tower (Fig. 1). Placed in the cradle, the payload experiences reduced gravity due to the cradle’s acceleration relative to the Earth's inertial frame. When the cradle is stationary with respect to the tower, it experiences normal Earth gravity (1g). However, when the cradle accelerates at a rate of ac, the effective gravity inside becomes geff = g + ac. For example, a downward acceleration of 1g (ac = -1g) cancels the effect of gravity, resulting in an effective gravity of 0 m/s2. The effective gravity within the cradle is therefore controlled by adjusting the cradle’s acceleration, which can be set in advance by the experimenter. The cradle is designed to accommodate various payloads – up to 250 kg – without the need for structural modifications, enabling a modular setup where different experiments can be designed for use within the facility.
The laboratory will use high-precision linear motors to control the cradle’s motion. Unlike conventional electric motors that generate rotational torque, linear motors are essentially "unrolled" to produce direct linear force through electromagnetic interaction. This design, combined with advanced control systems, enables precise regulation of the cradle's acceleration throughout the experiment. Furthermore, as the cradle will be magnetically guided this will also significantly reduce the frictional forces and enhance the system performance. At the end of its assisted fall, the cradle will be slowed by shock absorber cylinders, and brought to a stop with a deceleration lower than 15 g. On the cradle, two 220V sockets and 4 cables linked to an acquisition system are planned. The system will also provide measurements of accelerations and vibrations of the cradle, and configurable trigger signals.
To come even closer to space environment conditions, a vacuum tight container is designed to fit on the cradle (Fig. 2). This container will be able to accommodate experiments of ~0.7 x 1 m and up to 100 kg, and its transparent PMMA body enables to place monitoring equipment (e.g. cameras or laser measurements systems) outside vacuum. Pass-through ports are also available on the top of the container, for equipment placed under vacuum.
Figure 2: The vacuum tight container. Its internal diameter is 0.76m.
References
[1] ZARM, 2022. Bremen Drop Tower – Payload Unser’s Guide v 1.2. https://www.zarm.uni-bremen.de/fileadmin/user_upload/drop_tower/ZARM_BDT_PUG_ver1.2.pdf
[2] Pletser, V., et al. The First Joint European Partial-G Parabolic Flight Campaign at Moon and Mars Gravity Levels for Science and Exploration. Microgravity Sci. Technol. 24, 383–395 (2012).
[3] Collins, P.J., Grugel, R.N. and Radlińska, A., 2021. The Influence of Variable Gravity on the Microstructural Development of Tricalcium Silicate Pastes. In Earth and Space 2021 (pp. 59-66).
[4] Lotz, C., et al. (2017). Einstein-Elevator: A New Facility for Research from μ to 5. Gravitational and Space Research, 5(2), 11-27.
[5] Reitz, B., et al. Additive Manufacturing Under Lunar Gravity and Microgravity. Microgravity Sci. Technol. 33, 25 (2021). https://doi.org/10.1007/s12217-021-09878-4
[6] Gierse, A. et al., « The GraviTower Bremen Pro – Experiences with a next-generation drop tower system », 73rd International Astronautical Congress (IAC), Paris, France, 18-22 September 2022, IAC-22-A2-5-4-x6756.
[7] Sunday, C., et al. 2016. A novel facility for reduced-gravity testing: A setup for studying low-velocity collisions into granular surfaces. Review of Scientific Instruments, 87(8), p.084504.
Acknowledgements
The authors thank LateSys, the GRAVITE facility project team, and the project review board for their important contributions to this project. Funding support is acknowledged from the French ANR (ANR-23-ERCC-0003-01), and the European Research Council (ERC) GRAVITE project (Grant Agreement N°1087060).
How to cite: Wilhelm, A. and Murdoch, N.: The GRAVITE tower: Design updates for the new variable gravity facility, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–13 Sep 2025, EPSC-DPS2025-1355, https://doi.org/10.5194/epsc-dps2025-1355, 2025.