Many biological regulatory systems respond with a physiological delay when processing signals. A simple model of regulation which respects these features shows how the ability of a delayed output to transmit information is limited: at short times by the time scale of the dynamic input, at long times by that of the dynamic output. We find that topologies of maximally informative networks correspond to commonly occurring biological circuits linked to stress response and that circuits functioning out of steady state may exploit absorbing states to transmit information optimally.

In order to transmit biochemical signals, biological regulatory systems dissipate energy with concomitant entropy production. Additionally, signaling often takes place in challenging environmental conditions. In a simple model regulatory circuit given by an input and a delayed output, we explore the trade-offs between information transmission and the system's energetic efficiency. We determine the maximally informative network, given a fixed amount of entropy production and delayed response, exploring both the case with and without feedback. We find that feedback allows the circuit to overcome energy constraints and transmit close to the maximum available information even in the dissipationless limit. Negative feedback loops, characteristic of shock responses, are optimal at high dissipation. Close to equilibrium positive feedback loops, known for their stability, become more informative. Asking how the signaling network should be constructed to best function in the worst possible environment, rather than an optimally tuned one or in steady state, we discover that at large dissipation the same universal motif is optimal in all of these conditions.

<p>Data from martian rovers and martian meteorites indicate that ore minerals are common on Mars including sulfides such as pyrite, pyrrhotite, chalcopyrite and pentlandite. Three spectrometers: CRISM (The Compact Reconnaissance Imaging Spectrometer for Mars; spectral range 0.4−3.9 µm) onboard Mars Reconnaissance Orbiter (MRO), OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces et l’Activité; spectral range 0.4 - 5.1 µm), and PFS (Planetary Fourier Spectrometer; spectral range 1.3-45.0 µm) onboard Mars Express (MEX) operate in near infrared (NIR) spectrum and provide information on the mineral composition of Mars. However, none of those is yet capable to efficiently identify sulfides. Detecting sulfide ore deposits is difficult in the NIR range due to spectral interferences with silicates (Fig. 1). Due to the limited <em>in-situ</em> measurements by the Opportunity, Spirit, Curiosity, and Perseverance rovers, Mars mineralogical studies must be supported by studies of terrestrial analogs. The most suitable analog for study of ore minerals is the Rio Tinto area in Andalusia, Spain, which hosts the largest known volcanogenic massive sulfide deposits on Earth (Martin-Izard et al., 2015). In this area, we analyzed satellite images available in the near infrared spectrum, and thus Sentinel-2, ASTER, and Landsat 8. Principle Component Analysis (PCA) of the obtained spectra from Sentinel-2 (Fig. 2), which has the best field resolution (10 m) of the three, gives similar results to mineralogical data we have retrieved in the field during our geological mapping in March 2022 (see Ciazela J. et al., this session).</p> <p>By establishing our test field for remote sensing of sulfide deposits in a PFA site on Earth, we will be able to determine abundance thresholds for the detection of major sulfide phases on Mars and identify their key spectral features. Our results will help in 1) more efficient use of the current NIR Martian spectrometers to detect ore minerals and 2) designing new space instruments optimized for ore detection to include in future missions to Mars such as one developed at the Institute of Geological Sciences and the Space Research Centre of the Polish Academy of Sciences called MIRORES (Martian far-IR ORE Spectrometer).</p> <p>Acknowledgments: The presented research are supported by Europlanet2024-research infrastructure grant no. 20-EPN2-020 and National Science Centre of Poland project OPUS19 no. 2020/37/B/ST10/01420 to J. Ciazela.</p> <p>References:</p> <p>Horgan, B.H.N., Cloutis, E.A., Mann, P., Bell, J.F., 2014. Near-infrared spectra of ferrous mineral mixtures and methods for their identification in planetary surface spectra. Icarus 234, 132–154.</p> <p>Martin-Izard, A., Arias, D., Arias, M., Gumiel, P., Sanderson, D.J., Castañon, C., Lavandeira, A., Sanchez, J., 2015. A new 3D geological model and interpretation of structural evolution of the world-class Rio Tinto VMS deposit, Iberian Pyrite Belt (Spain). Ore Geol. Rev. 71, 457–476.</p> <p><img src="" alt="" /></p> <p><strong>Figure 1.</strong> Near-infrared (NIR) spectra of pyrites S142 and S29 compared to those of clinopyroxenes PYX126, PYX019, PYX009, and PYX115, which are all described by Horgan et al. (2014). Note the lack of distinct spectral features in pyrites and their similarity to the NIR spectra of some clinopyroxenes. Considering the low pyrite abundances compared to those of clinopyroxene, pyrite is difficult to observe in the NIR range. The y-axis has no numerical scale as the plots are shifted for clarity.</p> <p><img src="" alt="" width="1000" height="824" /></p> <p><strong>Figure 2.</strong> False-color composite, Sentinel-2A PCA (10 m/px) for the study area: PC1, PC2, and PC3 in R, G, and B channels, respectively. PCA image was calculated from the original 9-band (VNIR + SWIR) of Sentinel-2A (bands 1, 9, and 10 were excluded from this analysis as they do not contain mineralogical/geological information). Three first PCA components (PCA1, PCA2, and PCA3), containing the highest topographical and spectral information, are suitable for lithological discrimination, especially for arid region such study area. The pink color indicates areas with high pyrite content. The white frame in panel 'a' marks the region of the Rio Tinto Mining area in Spain. The white frame with the star in panel 'b' shows our study area for geological mapping (see Ciazela J. et al., this session).</p>

<p><strong>Introduction:</strong> This abstract deals with analysing the interaction between the ExoMars lander and the surface deformation at the touchdown in the Oxia Planum region of Mars. The analysis of ExoMars landing has been conducted by IRSPS under Thales Alenia Space Italia and ESA by means of computer simulations and physical test with a lander mock-up. The mission involves landing via retro-rockets to slow down the lander before impact. Despite the deceleration, the impact will transfer significant energies to the ground, exceeding those experienced in past missions.</p> <p><strong>Landing dynamics: </strong>Several variables of the descent phase influence the impact dynamics, such as the linear and the rotational terminal speeds, the inclination along the three axes, and the mass. We employed multi-body physics simulations to translate these input parameters into touchdown dynamics and ground stresses. The parameters and topographic data have been used in Unity and MATLAB environments to simulate the impacts. According to the Engineering Constraint of the mission [1], the topography has been modelled with slope values up to 20°.</p> <p><strong>Geotechnical parameters:</strong>  Estimating the geotechnical characteristics of Martian soil remains a rather complex challenge. After detailed mapping of the landing ellipse and a careful identification of the surface lithologies, we simulated different lithotypes: “Regolith” (poorly-sorted sand to cobble, loose, non-lithified material), “Mudstone” (silty marl and lithified clays with low calcite content), “Sandstone” (sandstones from deltaic and fluvial environments), “Halite” (evaporites from lacustrine/flood plain and deltaic interchannels), “Tuff” (pyroclastic material) and “Basalt” (lava flows). The geotechnical parameters have been extracted from terrestrial analogues and simulants and summarised in Table 1.</p> <p><img src="" alt="" width="1062" height="577" /></p> <p><strong>Geomechanical simulations:</strong> The numerical modelling of the stressed terrain has been performed with the Itasca FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) software. One hundred and eighteen different simulations have been performed, tuning the landing variables concerning the impact dynamics, the geotechnical parameters, and the topography. The input conditions of the individual tests were composed through the programming languages FLAC3D-embedded FISH and Python. Apart from “Regolith cases”, the simulations resulted in minimal and negligible displacement (below 1 mm), although it does not exclude minimal surface fracturing of the rock. The results indicate that in none of the cases did the pressures reach the bearing capacity of the lithotypes, remaining in the domain of elastic deformations. In “Regolith” cases, due to the lower capacity, the excavation of the pads reached a range of values up to 10 cm with low terrain slopes (Fig.1) and up to 20-25 cm at higher inclinations. The cases where the first impact occurs on a single pad showed the highest displacement rates, especially when the Landing Platform is inclined perpendicularly to the ground. Subsequent contacts with other pads resulted in lower displacements due to energy dissipation and impact geometry.</p> <p><img src="" alt="" width="1063" height="746" /></p> <p><strong>Field test campaign:</strong>  To validate the adopted methodology and get more details about the impact dynamics, a field tests campaign has been performed with a full-size mock-up of the Landing Platform. The mock-up structure replicates the same shape and physical dimensions of the real L.P. but with a mass scaled from the original to compensate for the difference in gravity (Fig.2). It is equipped with an onboard triaxial IMU, capable of recording system speed and attitude during impact. The launching system, designed to reach desired velocities and address the touchdown conditions, consists of an inclined rail of steel girders and a quick release system. As an analogue of the regolith terrain material, we used the argillitic sub-unit of the “Argille Varicolori” formation, outcropping in southern Abruzzo and Molise regions in Italy. Geotechnical laboratory tests on terrain samples confirmed that the material is a good compromise between regolith and the clay-bearing lithology observed in the landing area. The material used has been prepared and left to dry in a quarry specialised in handling such material. Surface deformation has been measured with sub-centimetric accuracy through laser scanner point clouds realised before and after the tests (Fig.3). Eight different field test scenarios have been performed and subsequently replicated in FLAC3D for comparison. The test configurations were chosen to be representative of the variability of previous geotechnical simulations. The comparison, summarised in Table 2, displays a mean percentage difference of -0.8% (standard deviation of 8.5%), reaching a maximum of -15%. Deformation rates are also compliant with the ranges observed on Mars simulations, up to 10 cm in flat terrain conditions and up to 17 cm at 20° of the slope.</p> <p><img src="" alt="" width="1061" height="601" /></p> <p><img src="" alt="" width="1081" height="1013" /></p> <p><img src="" alt="" width="1076" height="439" /></p> <p><strong>Conclusions:</strong> Surface deformation characterization studies have required the application of several simulations due to the wide variability of the physical, geological, and topographical factors involved. The field test campaign validated the methodology’s reliability and confirmed the expected deformation rates. The test results show that with significant thicknesses of regolith, the impact can lead to soil deformation rates ranging from five to more than twenty centimetres. Analyses of other lithotypes indicate more favourable results with negligible deformations due to not reaching the load bearing capacity. In both cases, the displacements should not reach values that compromise the onboard instrumentation, supporting landing safety in different surface conditions with a slope up to 20°.</p> <p><strong>References:</strong> [1] ESA (2013). ExoMars 2018 LSS UM Ref: EXM-SCI-LSS-ESA/IKI-003, Issue: 1.0, 17 Dec. 2013</p> <p> </p>

<p><strong>Introduction</strong></p> <p>Studying planetary field analog environments is a key point in order to define the physical and chemical parameters that favor life on Earth and other planets. Terrestrial hydrothermal springs have long been considered among the most significant planetary analogs searching for traces of life on Mars [1].</p> <p>Hyperspectral data have been recognised to be more suitable for the detailed mapping and identification of rocks and minerals identification of land surface, especially for minerals [2].</p> <p>Notwithstanding the technological advances, hyperspectral satellites are still poorly represented in spaceborne missions for Earth Exploration compared to multispectral ones. In this context, the Italian Space Agency (ASI) EO mission named PRISMA (PRecursore IperSpettrale della Missione Applicativa, [3]) offers a great opportunity to improve the knowledge about the scientific applications of spaceborne hyperspectral data.</p> <p>PRISMA, launched in March 2019, includes a panchromatic and a hyperspectral camera with 239 spectral bands. Specifically, the PRISMA satellite comprises a high-spectral resolution Visible Near InfraRed (VNIR) and Short-Wave InfraRed (SWIR) imaging spectrometer, ranging 400-2500 nm, with 30 m ground sampling distance (GSD) and 5 m GSD for the panchromatic camera [4].</p> <p>Our analysis with PRISMA images was mainly performed on an arid environment in a remote region of NE Ethiopia (Dallol; Long: 40.299351, Lat: 14.244367), representing an exceptional Mars analog due to diffuse hydrothermal alteration and the sulfate deposits evocative of past hydrothermal activity on Mars. This work aimed to obtain an identification map of minerals and their relative abundance using hyperspectral imaging to understand the potential of PRISMA as analog probe of Mars orbital instruments to detect and study possible analogs on Earth.</p> <p><strong>Study Area</strong></p> <p>Dallol is situated in the Danakil Depression, which is part of the East African Rift System. Principal geothermal features of the central crater area of Dallol are salt pillars, circular manifestations and acidic ponds. The northern and southern part is dominated by a salt dome structure and Salt pinnacles in the SW salt canyon area. The Black Mountain and the super-saline Black Lagoon, just south-southwest of Dallol, is an area of salt extrusions, geothermal manifestations and brine upflows.</p> <p>One advantage of this area is that the nebulosity is generally low, in fact the image selected during the dry season has a cloud coverage percentage of less than 1%. A salt suite was deposited and re-worked by hydrothermalism in the selected site. The characteristic minerals of the area are: carbonate, halite, carnallite and bischofite, anhydrite, gypsum, native sulfur of hydrothermal origin [5; 6].</p> <p>Flooding episodes from the Lake Assale to the north due to intense winds acting over the flat topography of the depression. The PRISMA SWIR Land/Water band combinations on the image selected, helped us to choose the region of interest around the Dallol area.</p> <p><strong>Operational Hyperspectral Processing</strong></p> <p>PRISMA images have three different levels of processing. Level 2C and 2D geolocated and atmospherically corrected images were used in this work and dated 21 August 2021. it is worth noticing that the images acquired on Dallol prior to the image selected for analysis had several preprocessing problems, particularly for stripe removal.</p> <p>The operational hyperspectral processing is composed of three main processing steps: (1) dimensionality reduction; (2) endmember identification and (3) mineral map distribution and abundance estimation.</p> <p>An unexpected result was obtained by applying an additional atmospheric correction, the Internal Average Relative Reflectance with Dark Subtraction, on the L2C image already corrected during the principal component analysis (PCA). The corrected atmospheric PCA allows better highlighting of geomorphological features.</p> <p>As for step (1), since hyperspectral images are composed of hundreds of extremely correlated bands, it is possible, and indeed beneficial, to reduce the effective dimension of the input data by removing bad bands.</p> <p>Step (2) was performed using the THOR Hyperspectral Material Identification (in ENVI 5.6) to identify unknown spectral signatures by comparing them with spectral libraries. This tool considers background statistics and image endmembers and can therefore provide accurate responses and spectra plots for rare or sub-pixel targets.</p> <p>Finally, the Spectral Angle Mapper (SAM) and the Linear Spectral Unmixing (LSU) tools were adopted for step (3). SAM determines the spectral similarity between two spectra by calculating the angle between the spectra and treating them as vectors in a space with dimensionality equal to the number of bands. LSU is a standard technique for spectral mixture analysis that infers a set of endmembers and fractions of these, called abundances. The mineral distribution and the abundance maps are shown respectively in Fig.1 and Fig.2.</p> <p><img src="" alt="" /></p> <p><strong>Conclusion</strong></p> <p>Six minerals have been recognised with the SAM classification from ENVI spectral library, in excellent agreement with the previous studies: carnallite, jarosite, kainite, polyhalite, gypsum and nontronite. The results confirm the mineralogical variability typical of the Dallol; in Fig.2, high mineral abundance values are shown in blue. The error calculated with the RMS is very low over the entire area of interest, except for the central zone where there are sulphur pools and therefore the presence of water does not favour this type of analysis. </p> <p>To better constrain the mineralogical mapping, future work will be conducted by a field exploration campaign to collect spectral signatures to be added to the ENVI library used, which so far could not be organised due to the ongoing civil war in Dankalia.</p> <p>To sum up, the study of terrestrial analogs can provide insights into the probable presence and nature of spring deposits on Mars, as well as help develop methods for classifying them from remote sensing data. PRISMA represents a valuable satellite for distinguishing not only the geometric characteristics of observed objects, but also the chemical-physical composition of the surface of the Earth.</p> <p><strong>References:</strong> [1] Walter, M.R. and Des Marais, D.J., 1993. Icarus 101:129–143 [2] Chang, C.I., 2007. John Wiley & Sons. 10.1002/0470124628 [3] Candela, L., et al. 2016. IEEE international geoscience and remote sensing symposium (IGARSS), 253-256. 10.1109/IGARSS.2016.7729057 [4] Loizzo, R., et al. 2019. IEEE (IGARSS), 4503-4506. 10.1109/IGARSS.2019.8899272 [5] Cavalazzi, B., et al. 2019. Astrobiology, 19(4), 553-578. 10.1089/AST.2018.1926 [6] López-García, J.M., et al. 2020. Frontiers in Earth Science, 7, 351. 10.3389/FEART.2019.00351</p>