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The next two rover missions to Mars, ESA/Roscosmos’s ExoMars2020 and NASA’s Mars2020, will carry for the first time Raman spectrometers potentially able to dectect traces of past or present life. To support and interpret future spectroscopic data correctly a better understanding of potential habitable environments and putative biosignatures, using analogue environments such as the Atacama Desert, is of paramount importance. In the Atacama Desert, one of the driest places on Earth, life has developed adaptive strategies to decreasing amounts of water: from refuges inside or below rocks as endoliths or hypoliths to inside salts in hygroscopic niches (Davila & Schulze-Makuch, 2016). In the hyperarid core one of the last refuges for life are inside salt crusts using deliquescence as a water source or being in the subsurface waiting for transitory episodes of increased moisture (Schulze-Makuch et al., 2018). These adaptive strategies might also apply to putative Martian life which endured a transition from a water rich past to the very harsh surface conditions of the present giving us clues on where to best look for traces of life on the Red Planet. Salt crusts and salt nodules are particularly interesting targets in this regard because they reside on or very near the surface and are thus easily accessible to future robotic missions. In the Atacama, salt nodules have been shown to host photosynthetic organisms containing easily identifiable pigments by Raman spectroscopy such as carotenoids and scytonemin (Vítek et al., 2014). One of the most damaging factors for life and its remains, both in the Atacama and on Mars, is solar radiation. To investigate the spatial distribution of potential Raman signatures in micro-niches we generated georeferenced 3D-reconstructions of the sampling areas using photogrammetry techniques and plotted the dose received according to the nodules’ orientation. We then analysed salt nodule along dry cut north-south thick sections using Raman mapping to infer any relations between the amount of light received and the presence of detectable signal. Preliminary data show an increased presence of carotenoids, scytonemin, and other biomolecules signals on the nodules oriented towards the south, which are the-more-protected sections of the nodules. References Davila, A.F. & Schulze-Makuch, D. (2016) The Last Possible Outposts for Life on Mars. Astrobiology 16:159–168. Schulze-Makuch, D., Wagner, D., Kounaves, S.P., Mangelsdorf, K., Devine, K.G., Vera, J.-P. de, Schmitt-Kopplin, P., Grossart, H.-P., Parro, V., Kaupenjohann, M., Galy, A., Schneider, B., Airo, A., Frösler, J., Davila, A.F., Arens, F.L., Cáceres, L., Cornejo, F.S., Carrizo, D., Dartnell, L., DiRuggiero, J., Flury, M., Ganzert, L., Gessner, M.O., Grathwohl, P., Guan, L., Heinz, J., Hess, M., Keppler, F., Maus, D., McKay, C.P., Meckenstock, R.U., Montgomery, W., Oberlin, E.A., Probst, A.J., Sáenz, J.S., Sattler, T., Schirmack, J., Sephton, M.A., Schloter, M., Uhl, J., Valenzuela, B., Vestergaard, G., Wörmer, L. & Zamorano, P. (2018) Transitory microbial habitat in the hyperarid Atacama Desert. PNAS 115:2670–2675. Vítek, P., Jehlička, J., Ascaso, C., Mašek, V., Gómez-Silva, B., Olivares, H. & Wierzchos, J. (2014) Distribution of scytonemin in endolithic microbial communities from halite crusts in the hyperarid zone of the Atacama Desert, Chile. FEMS Microbiology Ecology 90:351–366.

Cryptoendolithic microbial communities, discovered in the extremely cold, hyper-arid McMurdo Dry Valleys of Antarctica (Friedmann 1982), the most similar terrestrial environments to Mars surface (Wynn-Williams and Edwards 2000; Onofri et al., 2004), have been considered as a candidate in supporting the search of life in Mars exploration. In such harsh conditions, microorganisms grow in airspaces among mineral grains and show some adaptations, as the accumulation of protective pigments and compatible solutes, assuring their survival. In the frame of the Lichen and Fungi experiment (LIFE, P.I. Silvano Onofri; Onofri et al. 2012, 2015), small samples of these communities, were exposed to space, in the EXPOSE-E facility for 1.5 years, with an exposition to vacuum (10-7 to 10-4 Pa) (Horneck et al., 2010), galactic cosmic radiation (≤190mGy) (Berger et al., 2012), and the full spectrum of solar extraterrestrial electromagnetic radiation to which cryptoendolithic microorganisms demonstrated to survive (Scalzi et al., 2012). The search for trace of extant or extinct life is one of the main goals of the future space mission beyond Earth. The future rover missions ExoMars 2020 (ESA-Roscomos) and Mars 2020 (NASA) are exploring chemical and biological indicators of life, called biomarkers. A good biomarker must have a biogenic origin and thus must unequivocally be identified as possible trace of life. The detection of biomarkers on Mars was the aim of BIOMEX (BIOlogy and Mars Experiment) project, in which has been investigated the alteration of different biomarkers, after exposure to space and Mars-like conditions outside the International Space Station. In this contest, the aim of this work was to characterize fungal biomarkers from these exposed rock samples, with different approaches: i) Raman spectroscopy and InfraRed analyses, which has been considered excellent tools for the detection of inorganic and organic molecules, such as microbial pigments and ii) -omics approaches, as lipidomic and metabolomic techniques, performed to detect biological macromolecules and to determine their stability after space exposure. The focus of lipidomics and metabolomics has been on biomarker discovery, with the aim of identifying metabolites that are correlated with environmental exposures. The results suggest that microbial molecules can be detected through different techniques. In particular, our attention was focused on pigments, such as melanin and carotenoids that maintain their stability also after 1.5 years of space exposure. These results are of importance for the upcoming life-detection missions on Mars finalized for the search for past, extant or extinct life outside the Earth.

The question "Are we alone in the Universe?" is perhaps the most fundamental one that affects mankind. How can we address the search for life in our Solar System? Mars, Enceladus and Europa are the focus of the search for life outside the terrestrial biosphere. While it is more likely to find remnants of life (fossils of extinct life) on Mars because of its past short time window of the surface habitability, it is probably more likely to find traces of extant life on the icy moons and ocean worlds of Jupiter and Saturn. Nevertheless, even on Mars there could still be a chance to find extant life in niches near to the surface or in just discovered subglacial lakes beneath the South Pole ice cap. Here, the different approaches for the detection of traces of life in the form of biosignatures including prebiotic molecules will be presented. We will outline the required infrastructure for this enterprise and give examples of future mission concepts to investigate the presence of life on other planets and moons. Finally, we will provide suggestions on methods, techniques, operations and strategies for preparation and realization of future life detection missions.

Mars and the Jovian and Saturnian moons (Europa and Enceladus) are the next targets to search for life in our Solar System. New life detection instruments are indeed ready to be sent to Mars in 2020 (onboard ESA/Roscomos’s ExoMars2020 and NASA’s Mars2020 rovers) and possibly further. Among them, spectroscopy methods such as Raman or infrared are promising techniques that can give insights on both the mineralogical context and the identification of biosignatures. However, to support and interpret spectroscopic data correctly, as well as to guide future life detection missions, a better understanding of possibly habitable environments and potentially detectable biosignatures is of paramount importance. During the last years extensive field and laboratory investigations focused on demonstrating the capabilities of such technologies to characterize both mineral and biological samples of relevance to Mars but very few assessed potential biosignatures degradation under Mars-like or space-like conditions. To this end we are using samples from ground-based and space exposure experiments, the STARLIFE [1] and the BIOMEX [2] projects, to characterize their Raman and IR signatures after space and Mars relevant stresses. BIOMEX was part of the EXPOSE-R2 mission of the European Space Agency, which allowed a 15-month exposure on the outer side of the International Space Station and STARLIFE is an international campaign to study the role of galactic cosmic radiation in astrobiological systems. A wide range of extremophilic organisms such as cyanobacteria, permafrost green-algae, iron bacteria or methanogens and selected biomolecules exposed under these conditions will help us to define targets for future missions to Mars (and other bodies) carrying Raman, IR or LIBS spectrometers and give further clues about the potential habitability of Mars. We report, as an example, on the preservation potential of cyanobacterial photoprotective pigments (carotenoids) in the Antarctic cyanobacterium Nostoc cf. punctiforme strain CCCryo 231-06 after high doses of gamma irradiation and after space exposure [3]. [1] R. Moeller, M. Raguse, S. Leuko, T. Berger, C.E. Hellweg, A. Fujimori, R. Okayasu, and G. Horneck, Astrobiology, 17, 101–109 (2017). [2] J.-P. de Vera, M. Alawi, T. Backhaus, M. Baqué, D. Billi, U. Böttger, T. Berger, M. Bohmeier, C. Cockell, R. Demets, R. de la Torre Noetzel, H. Edwards, A. Elsaesser, C. Fagliarone, A. Fiedler, B. Foing, F. Foucher, J. Fritz, F. Hanke, et al., Astrobiology, 19, 145–157 (2019). [3] M. Baqué, F. Hanke, U. Böttger, T. Leya, R. Moeller, and J.-P. de Vera, Journal of Raman Spectroscopy, 49, 1617–1627 (2018).

The Moon is at the center of attention in many current plans for spaceflight activities, particularly manned missions. Significant progress has recently been made in the transportation to the Moon, and several institutes work on systems and system components to support human life on the surface of the Moon. One of these activities is project MaMBA (short for Moon and Mars Base Analog) which is located at the ZARM in Bremen and is dedicated to creating a full-scale, technologically functioning habitat. Unlike MaMBA, most of these projects focus on habitability alone – neglecting scientists’ desire to perform meaningful analyses, using the advantages of human presence at the location of interest. This approach is concurrent with how most spaceflight missions have been implemented in the past, adding scientific instruments after most of the engineering work is already finished. This often limited scientific studies to relatively scattered, insular topics. One of the main goals of project MaMBA is therefore to create a base that allows scientists to comprehensively study the most relevant areas of interest. Our focus is the in-base laboratory, and any equipment that should be available inside the habitat, but we also take into consideration instrumentation that may more efficiently be placed outside the habitat and/or on-board of rovers. The purpose of the habitat laboratory is to perform some basic investigations; in-depth analyses of selected samples are supposed to remain within the responsibility of Earth-based laboratories. However, the base may help chose which samples should be sent to Earth for further analysis. The authors of this paper represent different disciplines with a particular interest in scientific exploitation of the Moon. These represented disciplines are: geology, materials science, astrochemistry, astrobiology, medicine, and astronomy. We will present what we deem some of the most important questions that could be addressed on the Moon, and how these may be addressed efficiently instrument-wise. We will consider synergies between the different disciplines, saving weight and space wherever possible, and make recommendations for a to-be-built lunar base. While the direct addressee of our recommendations is the MaMBA laboratory, most of them are also applicable to general non-terrestrial surface laboratories.

The future search-for-life missions to Mars - ESA/Roscosmos’s ExoMars2020 and NASA’s Mars2020 rovers - will carry Raman spectrometers for in situ analysis of extraterrestrial material for the first time1,2. The question remains whether signs of extinct or extant life could be detected by this method. From our terrestrial examples, carotenoids (e.g. serving in cyanobacteria as accessory and photoprotective pigments) have been extensively used as biosignature models due to their stability and easy identification by Raman spectroscopy with a 532nm excitation wavelength3. Evaluating the detection limit of pigments under simulated extraterrestrial conditions is beneficial for the success of future life-detection missions. Ionizing radiation can be considered the most deleterious factor for the long term preservation of potential biomarkers on Mars4. Here, we report on the preservation potential of Raman signatures in the Antarctic cyanobacterium Nostoc sp. strain CCCryo 231–06 after high doses of gamma irradiation performed in the frame of the STARLIFE project5. The carotenoids' signals usually dominate the Raman spectra at 532nm excitation wavelength due to resonance effects. But comparing their distribution and quantifying their preservation is still problematic in natural samples. To standardize the analyses, we successfully applied Raman mapping and signal-to-noise ratios (SNR) masks to quantify the effects of irradiation. The typical in vivo Raman signatures of carotenoids could be detected even after exposure to up to 56 kGy with significant deterioration in terms of signal coverage and SNR. However, for colonies embedded in two different Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants), the carotenoids' signatures remained detectable even after the highest dose of γ-rays (117kGy) tested in this study, with no significant effect on signal coverage or SNRs. Carotenoids proved again their scientific value as model biosignatures for future life detection missions on Mars. Data gathered during these ground-based irradiation experiments contribute to interpret results from space experiments (such as BIOMEX6) and will guide our search for life on Mars and other bodies of interest.

Mankind may be only decades away from establishing a long-term presence on our moon and on Mars. With the right equipment, this presence can lead to immense advances in diverse scientific fields. We here discuss how laboratories on the Moon and Mars could be equipped to answer astrobiological questions pertaining (among others) to: i) the limits for life beyond Earth, ii) the search for extraterrestrial life, iii) the origins and early development of life, iv) biological life-support systems (BLSS), and v) microbiome evolution and containment.

The BIOMEX (BIOlogy and Mars EXperiment) experiment aims at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions in the presence of Martian mineral analogues (de Vera et al. 2012). To this end, extensive ground-based simulation studies and a space experiment were performed. Indeed, BIOMEX was part of the EXPOSE-R2 mission of the European Space Agency which allowed a 15-month exposure, on the outside of the International Space Station, of four astrobiology experiments between July 2014 and February 2016. The preservation and evolution of Raman biosignatures under real space conditions is of particular interest for guiding future search-for-life missions to Mars (and other planetary objects) carrying Raman spectrometers (such as the Raman Laser Spectrometer instrument on board the future ExoMars rover). Among the potential biosignatures investigated, the photoprotective carotenoid pigments (present either in photosynthetic organisms such as plants, algae, cyanobacteria and in some bacteria and archaea) have been classified as high priority targets for biomolecule detection on Mars and therefore used as biosignature models due to their stability and easy identification by Raman spectroscopy (Böttger et al. 2012). We report here on the first results from the analysis of two carotenoids containing organisms: the cyanobacterium Nostoc sp. (strain CCCryo 231-06; = UTEX EE21 and CCMEE 391) isolated from Antarctica and the green alga cf. Sphaerocystis sp. (strain CCCryo 101-99) isolated from Spitsbergen. Desiccated cells of these organisms were exposed to space and simulated Mars-like conditions in space in the presence of two Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) and a Lunar regolith analogue and analyzed with a 532nm Raman microscope at 1mW laser power. Carotenoids in both organisms were surprisingly still detectable at relatively high levels after being exposed for 15 months in Low Earth Orbit to UV, cosmic rays, vacuum (or Mars-like atmosphere) and temperatures stresses regardless of the mineral matrix used. Further analyses will help us to correlate these results with survival potential, cellular damages or stability and the different extremophiles tested in the BIOMEX experiment.

Forty years after the Viking missions, International space agencies are ready to resume the search for life on Mars (and in our Solar System). Indeed, new instruments are able to detect traces of extant or extinct life. They will be sent to Mars onboard the two next rovers: ExoMars2020 and Mars2020. Among them, instruments based on Raman spectroscopy are very promising thanks to their capacity to identify both the mineralogical context and organic molecules of potential biogenic origin. However, in order to support these future missions, it is very important to investigate the degree of preservation and the evolution of potential biosignatures under simulated and real space conditions by Raman spectroscopy. To this end, the BIOMEX (BIOlogy and Mars EXperiment) experiment aims at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions in the presence of Martian mineral analogues (de Vera et al. 2012). BIOMEX was part of the EXPOSE-R2 mission of the European Space Agency which allowed a 15-month exposure, on the outer side of the International Space Station, which comprises also three other astrobiology experiments between July 2014 and February 2016. Among the potential biosignatures investigated, the photoprotective carotenoid pigments (present either in photosynthetic organisms such as plants, algae, cyanobacteria and in some bacteria and archaea) have been classified as high priority targets for biomolecule detection on Mars and therefore used as a model biosignature due to their stability and easy identification by Raman spectroscopy (Böttger et al. 2012). We report here on the first results from the analysis of two carotenoids containing organisms: the cyanobacterium Nostoc sp. (strain CCCryo 231-06; = UTEX EE21 and CCMEE 391) isolated from Antarctica and the green alga cf. Sphaerocystis sp. (strain CCCryo 101-99) isolated from Spitsbergen. Desiccated cells of these organisms were exposed to space conditions and to simulated Mars-like conditions in space. They were cultured on Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) and a Lunar regolith analogue and analyzed with a 532nm Raman spectroscope operating at 1mW laser power. Carotenoids in both organisms were surprisingly still detectable at relatively high levels after being exposed for 15 months in Low Earth Orbit to UV, cosmic rays, vacuum (or Mars-like atmosphere) and temperatures stresses regardless of the mineral matrix used. Further analyses will help us to correlate these results with survival potential, cellular damages or stability and the different extremophiles tested in the BIOMEX experiment.

After a 15-month exposure onboard the EXPOSE-R2 space platform, situated on the outside of the International Space Station, four astrobiology experiments successfully came back to Earth in March and June 2016. Among them, the BIOMEX (BIOlogy and Mars EXperiment) experiment aims at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions in the presence of Martian mineral analogues [1]. The preservation and evolution of Raman biosignatures under such conditions is of particular interest for guiding future search-for-life missions to Mars (and other planetary objects) carrying Raman spectrometers (such as the Raman Laser Spectrometer instrument on board the future ExoMars rover). The photoprotective carotenoid pigments (present either in photosynthetic organisms such as plants, algae, cyanobacteria and in some bacteria and archaea) have been classified as high priority targets for biomolecule detection on Mars and therefore used as biosignature models due to their stability and easy identification by Raman spectroscopy [2]. We report here on the first results from the analysis of two carotenoids containing organisms: the cyanobacterium Nostoc sp. (strain CCCryo 231-06; = UTEX EE21 and CCMEE 391) isolated from Antarctica and the green alga cf. Sphaerocystis sp. (strain CCCryo 101-99) isolated from Spitsbergen. Desiccated cells of these organisms were exposed to space and simulated Mars-like conditions in space in the presence of two Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) and a Lunar regolith analogue and analyzed with a 532nm Raman microscope at 1mW laser power. Carotenoids in both organisms were surprisingly still detectable at relatively high levels after being exposed for 15 months in Low Earth Orbit to UV, cosmic rays, vacuum (or Mars-like atmosphere) and temperatures stresses regardless of the mineral matrix used. Further analyses will help us to correlate these results with survival potential, cellular damages or stability and the different extremophiles tested in the BIOMEX experiment.

Chroococcidiopsis is a unicellular cyanobacterial genus that is growing in extreme dry conditions, either in low or high temperatures. At the lower end of the spectrum, they live as cryptoendoliths in rocks of the Mc Murdo Dry Valleys in Antarctica where they were discovered by Imre Friedmann, while at the higher end, they grow as hypoliths/endoliths in hot deserts, e.g. Negev, Gobi, Atacama (Friedman, 1980). The capacity of desert strains of Chroococcidiopsis to stabilize their sub-cellular organization is so efficient that, when dried, they can cope with simulated space and Martian conditions (Billi et al 2011 ; Baqué et al. 2013a) as well as with high doses of ionizing and UV radiations (Verseux et al. 2017 ; Baqué et al. 2013b). Since it is known for radiation/desiccation tolerant bacteria that the capability to avoid protein oxidation is critical to cope with such stressors (Frederickson et al. 2008; Daly et al. 2007), the present study investigates the protein oxidation after prolonged desiccation, irradiation with gamma-rays up to 25kGy and treatment with hydrogen peroxide in a selection of desert Chroococcidiopsis isolates, including 2 Antarctic strains: CCMEE134 and CMEE171 isolated from Beacon Valley and University Valley, respectively (Mc Murdo Dry Valleys). A tight correlation was observed between the desiccation and radiation tolerance of the investigated desert strains and the absence of oxidative damage to proteins. The efficiency of the antioxidant systems of the desert strains of Chroococcidiopsis was highlighted also by the lack of protein carbonylation until treatment with 1M of oxygen peroxide. The phylogenetic analysis of the investigated 11 desert strains of Chroococcidiopsis is reported. References Baqué, M. et al. 2013a. Biofilm and planktonic lifestyles differently support the resistance of the desert cyanobacterium Chroococcidiopsis under space and Martian simulations. Origin of Life and Evolution of Biospheres 3,377-89. Baqué, M. et al. 2013b. Endurance of the endolithic desert cyanobacterium Chroococcidiopsis under UVC radiation. Extremophiles 17,161-169. Billi, D. et 2011. Damage escape and repair in dried Chroococcidiopsis spp. from hot and cold deserts exposed to simulated space and Martian conditions. Astrobiology 11,65-73. Daly, M.J. et al., 2007. Protein oxidation implicated as the primary determinant of bacterial radioresistance. PLoS Biology, 5(4), p.e92. Fredrickson, J.K. et al. (2008) Protein oxidation: key to bacterial desiccation resistance? Int J Syst Evol Microbiol 2:393-403 Friedmann, E.I. 1980. Endolithic microbial life in hot and cold deserts. Origins of Life and Evolution of Biospheres10, 223-235. Verseux, C. et al. 2017. Evaluation of the resistance of Chroococcidiopsis spp. to sparsely and densely ionizing irradiation. Astrobiology 17,118-125 This work was supported by the Italian National Antarctic Research Program This work is dedicated to the memory of Roseli Ocampo-Friedmann and E. Imre Friedmann who pioneered the research on Chroococcidiopsis and life in extreme environments

The challenge in astrobiology and planetary research in the near future is to realize space missions to study the habitability of Mars and the icy moons of the Jovian and Saturnian systems. Mars is an interesting object to search for habitable environments and for fossilized (and potentially present) life because of its past water driven wet history. On the other hand the Jovian moon Europa and the Saturnian moon Enceladus are promising candidates, where liquid water oceans beneath the surface are expected. These oceans can be habitable environments and the next challenge is to search there for present life. Some examples on potential biospheres and their biosignatures in Mars-like environments and in environmental conditions with reference to the icy moons will be given, which might exist in such kind of icy environments.

International audience; Not Available

Symposium F, session 33, paper number F33-0013-10 (Poster, Nr. Tue-250); International audience; The search for the first steps of a prebiotic chemistry and the detection of life in the Solar System are ones of the great challenges of new upcoming space missions. In particular, some instruments will be designed to detect traces of organic matter on extra-terrestrial objects like Mars, Titan, comets, etc. A new and promising technique based on biochips is recommended by space agencies (ESA and NASA). A biochip is a miniaturized device composed of biological sensitive systems grafted on a slide. It allows the quantification of numerous target molecules simultaneously (from hundreds to thousands). With the support of the French space agency (CNES), our team currently develops a biochip especially designed for planetary exploration. The BiOMAS (Biochip for Organic Matter Analysis in Space) project, in progress for four years, has an interdisciplinary dimension bringing together specialists evolving in different area (planetology, physics, chemistry, biology and materials science) and developing complementary competences. A space biochip should be highly sensitive, specific and robust, allowing the detection of traces of various organic molecules (individuals and families). Since the conception of the biochip is at the heart of the instrumental specification, our aim is to optimize all the components (including the slide material, the ligands, the chemical bonds and the detection system) in order to meet both analytical and space constraints. Two different types of ligands (antibodies and aptamers) are under study to reach this objective. In space conditions, a lot of constraints might alter the efficiency of this analytical tool (irradiation by cosmic rays, temperature variations, vacuum, long duration mission, etc). Therefore, designing such a biochip requires testing the resistance of all its components to space conditions. Main concepts and current developments of the project are presented.

Even in one of the driest places on Earth, the Atacama Desert, life has found adaptive strategies to decreasing amounts of water: from refuges inside or below rocks as endoliths or hypoliths to inside salts in hygroscopic niches [1]. In the hyperarid core though, one of the last refuges for life are inside salt crusts using deliquescence as a water source or in the subsurface waiting for transitory episodes of increased moisture [2]. These adaptive strategies might also apply to a putative Martian life which endured a transition from a water rich past to the very harsh surface conditions of the present and giving us clues on where to best look for traces of life on the Red Planet. Salt crusts and salt nodules are particularly interesting targets in this regard because they reside on or very near the surface and are thus easily accessible to future robotic missions. In the Atacama, salt nodules have been shown to host photosynthetic organisms containing easily identifiable pigments by Raman spectroscopy such as carotenoids or scytonemin. Mostly composed of halite, they are associated with polygonated soils, but their formation processes are still not fully understood. Salt nodules occur in varying morphologies which can control micro-environmental conditions and possibly microbial colonization (habitation of “micro-niches”). One of the most damaging factors for life and its remains, both in the Atacama and on Mars, is solar radiation. To investigate the distribution of potential Raman signatures in micro-niches we mapped/reconstructed the sampling areas using photogrammetry techniques and plotted the dose received according to the nodules’ orientation. We then analysed salt nodules sections using Raman mapping to infer any relations between the amount of light received and the presence of detectable signal. Raman instruments are indeed part of the next two rover missions to Mars: ESA/Roscosmos’s ExoMars2020 and NASA’s Mars2020. To support and interpret future spectroscopic data correctly, a better understanding of potential habitable environments and putative biosignatures, using analogue environments such as the Atacama Desert, is of paramount importance. [1] A.F. Davila and D. Schulze-Makuch, Astrobiology, 16,159-168, (2016). [2] D. Schulze-Makuch, D. Wagner, S.P. Kounaves, K. Mangelsdorf, K.G. Devine, J.-P. de Vera, P. Schmitt-Kopplin, H.-P. Grossart, V. Parro, M. Kaupenjohann, A. Galy, B. Schneider, A. Airo, J. Frösler, A.F. Davila, F.L. Arens, L. Cáceres, F.S. Cornejo, D. Carrizo, et al., PNAS, 115, 2670–2675 (2018).