| 1. |
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| 2. |
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| 3. |
- Azua-Bustos, Armando, et al.
(författare)
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Aeolian transport of viable microbial life across the Atacama Desert, Chile : Implications for Mars
- 2019
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Ingår i: Scientific Reports. - : Springer. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Here we inspect whether microbial life may disperse using dust transported by wind in the Atacama Desert in northern Chile, a well-known Mars analog model. By setting a simple experiment across the hyperarid core of the Atacama we found that a number of viable bacteria and fungi are in fact able to traverse the driest and most UV irradiated desert on Earth unscathed using wind-transported dust, particularly in the later afternoon hours. This finding suggests that microbial life on Mars, extant or past, may have similarly benefited from aeolian transport to move across the planet and find suitable habitats to thrive and evolve.
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| 4. |
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| 5. |
- Bhardwaj, Anshuman, et al.
(författare)
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Are Slope Streaks Indicative of Global‐Scale Aqueous Processes on Contemporary Mars?
- 2019
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Ingår i: Reviews of geophysics. - : American Geophysical Union (AGU). - 8755-1209 .- 1944-9208. ; 57:1, s. 48-77
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Tidskriftsartikel (refereegranskat)abstract
- Slope streaks are prevalent and intriguing dark albedo surface features on contemporary Mars. Slope streaks are readily observed in the equatorial and subequatorial dusty regolith regions with low thermal inertia. They gradually fade over decadal timescales. The proposed mechanisms for their formation vary widely based on several physicochemical and geomorphological explanations. The scientific community is divided in proposing both dry and wet mechanisms for the formation of slope streaks. Here we perform a systematic evaluation of the literature for these wet and dry mechanisms. We discuss the probable constraints on the various proposed mechanisms and provide perspectives on the plausible process driving global‐scale slope streak formation on contemporary Mars. Although per our understanding, a thorough consideration of the global distribution of slope streaks, their morphology and topography, flow characteristics, physicochemical and atmospheric coincidences, and terrestrial analogies weighs more in favor of several wet mechanisms, we acknowledge that such wet mechanisms cannot explain all the reported morphological and terrain variations of slope streaks. Thus, we suggest that explanations considering both dry and wet processes can more holistically describe all the observed morphological variations among slope streaks. We further acknowledge the constraints on the resolutions of remote sensing data and on our understanding of the Martian mineralogy, climate, and atmosphere and recommend continuous investigations in this direction using future remote sensing acquisitions and simulations. In this regard, finding more wet and dry terrestrial analogs for Martian slope streaks and studying them at high spatiotemporal resolutions can greatly improve our understanding.
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| 6. |
- Bhardwaj, Anshuman, et al.
(författare)
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Discovery of recurring slope lineae candidates in Mawrth Vallis, Mars
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Several interpretations of recurring slope lineae (RSL) have related RSL to the potential presence of transient liquid water on Mars. Such probable signs of liquid water have implications for Mars exploration in terms of rover safety, planetary protection during rover operations, and the current habitability of the planet. Mawrth Vallis has always been a prime target to be considered for Mars rover missions due to its rich mineralogy. Most recently, Mawrth Vallis was one of the two final candidates selected by the European Space Agency as a landing site for the ExoMars 2020 mission. Therefore, all surface features and landforms in Mawrth Vallis that may be of special interest in terms of scientific goals, rover safety, and operations must be scrutinised to better assess it for future Mars missions. Here, we report on the initial detection of RSL candidates in two craters of Mawrth Vallis. The new sightings were made outside of established RSL regions and further prompt the inclusion of a new geographical region within the RSL candidate group. Our inferences on the RSL candidates are based on several morphological and geophysical evidences and analogies: (i) the dimensions of the RSL candidates are consistent with confirmed mid-latitude RSL; (ii) albedo and thermal inertia values are comparable to those of other mid-latitude RSL sites; and (iii) features are found in a summer season image and on the steep and warmest slopes. These results denote the plausible presence of transient liquid brines close to the previously proposed landing ellipse of the ExoMars rover, rendering this site particularly relevant to the search of life. Further investigations of Mawrth Vallis carried out at higher spatial and temporal resolutions are needed to identify more of such features at local scales to maximize the scientific return from the future Mars rovers, to prevent probable biological contamination during rover operations, to evade damage to rover components as brines can be highly corrosive, and to quantify the ability of the regolith at mid-latitudes to capture atmospheric water which is relevant for in-situ-resource utilization.
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| 7. |
- Bhardwaj, Anshuman, et al.
(författare)
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Distribution and Morphologies of Transverse Aeolian Ridges in ExoMars 2020 Rover Landing Site
- 2019
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Ingår i: Remote Sensing. - : MDPI. - 2072-4292. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Aeolian processes are believed to play a major role in the landscape evolution of Mars. Investigations on Martian aeolian landforms such as ripples, transverse aeolian ridges (TARs), and dunes, and aeolian sediment flux measurements are important to enhance our understanding of past and present wind regimes, the ongoing dust cycle, landscape evolution, and geochemistry. These aeolian bedforms are often comprised of loose sand and sharply undulating topography and thus pose a threat to mobility and maneuvers of Mars rovers. Here we present a first-hand account of the distribution, morphologies, and morphometrics of TARs in Oxia Planum, the recently selected ExoMars 2020 Rover landing site. The gridded mapping was performed for contiguous stretches of TARs within all the landing ellipses using 57 sub-meter high resolution imaging science experiment (HiRISE) scenes. We also provide the morphological descriptions for all types of TARs present within the landing ellipses. We use HiRISE digital terrain models (DTMs) along with the images to derive morphometric information for TARs in Oxia Planum. In general, the average areal TAR coverage was found to be 5.4% (±4.9% standard deviation), increasing from west to east within the landing ellipses. We report the average TAR morphometrics in the form of crest–ridge width (131.1 ± 106.2 m), down-wind TAR length (17.6 ± 10.1 m), wavelength (37.3 ± 11.6 m), plan view aspect ratio (7.1 ± 2.3), inter-bedform spacing (2.1 ± 1.1), slope (10.6° ± 6.1°), predominant orientations (NE-SW and E-W), and height (1.2 ± 0.8 m). While simple TARs are predominant, we report other TAR morphologies such as forked TAR, wavy TAR with associated smaller secondary ripples, barchan-like TAR, networked TAR, and mini-TARs from the region. Our results can help in planning the rover traverses in terms of both safe passage and scientific returns favoring aeolian research, particularly improving our understanding of TARs.
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| 8. |
- Bhardwaj, Anshuman, et al.
(författare)
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Martian slope streaks as plausible indicators of transient water activity
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Slope streaks have been frequently observed in the equatorial, low thermal inertia and dusty regions of Mars. The reason behind their formation remains unclear with proposed hypotheses for both dry and wet mechanisms. Here, we report an up-to-date distribution and morphometric investigation of Martian slope streaks. We find: (i) a remarkable coexistence of the slope streak distribution with the regions on Mars with high abundances of water-equivalent hydrogen, chlorine, and iron; (ii) favourable thermodynamic conditions for transient deliquescence and brine development in the slope streak regions; (iii) a significant concurrence of slope streak distribution with the regions of enhanced atmospheric water vapour concentration, thus suggestive of a present-day regolith-atmosphere water cycle; and (iv) terrain preferences and flow patterns supporting a wet mechanism for slope streaks. These results suggest a strong local regolith-atmosphere water coupling in the slope streak regions that leads to the formation of these fluidised features. Our conclusions can have profound astrobiological, habitability, environmental, and planetary protection implications
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| 9. |
- Bhardwaj, Anshuman, et al.
(författare)
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UAV Imaging of a Martian Brine Analogue Environment in a Fluvio-Aeolian Setting
- 2019
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Ingår i: Remote Sensing. - : MDPI. - 2072-4292. ; 11:18
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Tidskriftsartikel (refereegranskat)abstract
- Understanding extraterrestrial environments and landforms through remote sensing and terrestrial analogy has gained momentum in recent years due to advances in remote sensing platforms, sensors, and computing efficiency. The seasonal brines of the largest salt plateau on Earth in Salar de Uyuni (Bolivian Altiplano) have been inadequately studied for their localized hydrodynamics and the regolith volume transport across the freshwater-brine mixing zones. These brines have recently been projected as a new analogue site for the proposed Martian brines, such as recurring slope lineae (RSL) and slope streaks. The Martian brines have been postulated to be the result of ongoing deliquescence-based salt-hydrology processes on contemporary Mars, similar to the studied Salar de Uyuni brines. As part of a field-site campaign during the cold and dry season in the latter half of August 2017, we deployed an unmanned aerial vehicle (UAV) at two sites of the Salar de Uyuni to perform detailed terrain mapping and geomorphometry. We generated high-resolution (2 cm/pixel) photogrammetric digital elevation models (DEMs) for observing and quantifying short-term terrain changes within the brines and their surroundings. The achieved co-registration for the temporal DEMs was considerably high, from which precise inferences regarding the terrain dynamics were derived. The observed average rate of bottom surface elevation change for brines was ~1.02 mm/day, with localized signs of erosion and deposition. Additionally, we observed short-term changes in the adjacent geomorphology and salt cracks. We conclude that the transferred regolith volume via such brines can be extremely low, well within the resolution limits of the remote sensors that are currently orbiting Mars, thereby making it difficult to resolve the topographic relief and terrain perturbations that are produced by such flows on Mars. Thus, the absence of observable erosion and deposition features within or around most of the proposed Martian RSL and slope streaks cannot be used to dismiss the possibility of fluidized flow within these features
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| 10. |
- Castro, Juan Francisco Buenestado, et al.
(författare)
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Liquid water at crater Gale, Mars
- 2015
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Ingår i: Journal of Astrobiology and Outreach. - : OMICS Publishing Group. - 2332-2519. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Suspicion that Mars could have transient liquid water on its surface through deliquescence of salts to form aqueous solutions or brines is an old proposal whose inquiry was boosted by Phoenix Lander observations. It provided some images of what were claimed to be brines, the presence of which at its landing site was compatible with the atmospheric parameters and the composition of the soil observed. On the other hand, the so called Recurrent Slope Lineae (RSL) often imaged by orbiters, were considered as another clue pointing to the occurrence of the phenomenon, since it was thought that they might be caused by it. Now, Curiosity rover has performed the first in-situ multi-instrumental study on Mars’ surface, having collected the most comprehensive environmental data set ever taken by means of their instruments Rover Environmental Monitoring Station (REMS), Dynamic Albedo of Neutrons (DAN), and Sample Analysis at Mars (SAM). REMS is providing continuous and accurate measurements of the relative humidity and surface and air temperatures among other parameters, and DAN and SAM provide the water content of the regolith and the atmosphere respectively. Analysis of these data has allowed to establish the existence of a present day active water cycle between the atmosphere and the regolith, that changes according to daily and seasonal cycles, and that is mediated by the presence of brines during certain periods of each and every day. Importantly, the study shows that the conditions for the occurrence of deliquescence are favourable even at equatorial latitudes where, at first, it was thought they were not due to the temperature and relative humidity conditions. This study provides new keys for the understanding of martian environment, and opens interesting lines of research and studies for future missions which may even have a bearing on extant microbial life.
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| 11. |
- Cockell, C.S., et al.
(författare)
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Habitability : a review
- 2016
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Ingår i: Astrobiology. - : Mary Ann Liebert Inc. - 1531-1074 .- 1557-8070. ; 16:1, s. 89-117
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Tidskriftsartikel (refereegranskat)abstract
- Habitability is a widely used word in the geoscience, planetary science, and astrobiology literature, but what does it mean? In this review on habitability, we define it as the ability of an environment to support the activity of at least one known organism. We adopt a binary definition of “habitability” and a “habitable environment.” An environment either can or cannot sustain a given organism. However, environments such as entire planets might be capable of supporting more or less species diversity or biomass compared with that of Earth. A clarity in understanding habitability can be obtained by defining instantaneous habitability as the conditions at any given time in a given environment required to sustain the activity of at least one known organism, and continuous planetary habitability as the capacity of a planetary body to sustain habitable conditions on some areas of its surface or within its interior over geological timescales. We also distinguish between surface liquid water worlds (such as Earth) that can sustain liquid water on their surfaces and interior liquid water worlds, such as icy moons and terrestrial-type rocky planets with liquid water only in their interiors. This distinction is important since, while the former can potentially sustain habitable conditions for oxygenic photosynthesis that leads to the rise of atmospheric oxygen and potentially complex multicellularity and intelligence over geological timescales, the latter are unlikely to. Habitable environments do not need to contain life. Although the decoupling of habitability and the presence of life may be rare on Earth, it may be important for understanding the habitability of other planetary bodies
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| 12. |
- Cockell, Charles S., et al.
(författare)
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Sample Collection and Return from Mars : Optimising Sample Collection Based on the Microbial Ecology of Terrestrial Volcanic Environments
- 2019
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Ingår i: Space Science Reviews. - : Springer. - 0038-6308 .- 1572-9672. ; 215:7
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Forskningsöversikt (refereegranskat)abstract
- With no large-scale granitic continental crust, all environments on Mars are fundamentally derived from basaltic sources or, in the case of environments such as ices, evaporitic, and sedimentary deposits, influenced by the composition of the volcanic crust. Therefore, the selection of samples on Mars by robots and humans for investigating habitability or testing for the presence of life should be guided by our understanding of the microbial ecology of volcanic terrains on the Earth. In this paper, we discuss the microbial ecology of volcanic rocks and hydrothermal systems on the Earth. We draw on microbiological investigations of volcanic environments accomplished both by microbiology-focused studies and Mars analog studies such as the NASA BASALT project. A synthesis of these data emphasises a number of common patterns that include: (1) the heterogeneous distribution of biomass and diversity in all studied materials, (2) physical, chemical, and biological factors that can cause heterogeneous microbial biomass and diversity from sub-millimetre scales to kilometre scales, (3) the difficulty of a priori prediction of which organisms will colonise given materials, and (4) the potential for samples that are habitable, but contain no evidence of a biota. From these observations, we suggest an idealised strategy for sample collection. It includes: (1) collection of multiple samples in any given material type (∼9 or more samples), (2) collection of a coherent sample of sufficient size (∼10 cm3∼10 cm3) that takes into account observed heterogeneities in microbial distribution in these materials on Earth, and (3) collection of multiple sample suites in the same material across large spatial scales. We suggest that a microbial ecology-driven strategy for investigating the habitability and presence of life on Mars is likely to yield the most promising sample set of the greatest use to the largest number of astrobiologists and planetary scientists.
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| 13. |
- Cockell, Charles S., et al.
(författare)
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Subsurface scientific exploration of extraterrestrial environments (MINAR 5) : analogue science, technology and education in the Boulby Mine, UK
- 2019
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Ingår i: International Journal of Astrobiology. - : Cambridges Institutes Press. - 1473-5504 .- 1475-3006. ; 18:2, s. 157-182
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Tidskriftsartikel (refereegranskat)abstract
- The deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testing methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation.
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| 14. |
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| 15. |
- Delgado-Bonal, Alfonso, et al.
(författare)
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Solar and wind exergy potentials for Mars
- 2016
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 102, s. 550-558
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Tidskriftsartikel (refereegranskat)abstract
- The energy requirements of the planetary exploration spacecrafts constrain the lifetime of the missions, their mobility and capabilities, and the number of instruments onboard. They are limiting factors in planetary exploration. Several missions to the surface of Mars have proven the feasibility and success of solar panels as energy source. The analysis of the exergy efficiency of the solar radiation has been carried out successfully on Earth, however, to date, there is not an extensive research regarding the thermodynamic exergy efficiency of in-situ renewable energy sources on Mars. In this paper, we analyse the obtainable energy (exergy) from solar radiation under Martian conditions. For this analysis we have used the surface environmental variables on Mars measured in-situ by the Rover Environmental Monitoring Station onboard the Curiosity rover and from satellite by the Thermal Emission Spectrometer instrument onboard the Mars Global Surveyor satellite mission. We evaluate the exergy efficiency from solar radiation on a global spatial scale using orbital data for a Martian year; and in a one single location in Mars (the Gale crater) but with an appreciable temporal resolution (1 h). Also, we analyse the wind energy as an alternative source of energy for Mars exploration and compare the results with those obtained on Earth. We study the viability of solar and wind energy station for the future exploration of Mars, showing that a small square solar cell of 0.30 m length could maintain a meteorological station on Mars. We conclude that the low density of the atmosphere of Mars is responsible of the low thermal exergy efficiency of solar panels. It also makes the use of wind energy uneffective. Finally, we provide insights for the development of new solar cells on Mars.
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| 16. |
- Escamilla-Roa, Elizabeth, et al.
(författare)
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DFT study of the reduction reaction of calcium perchlorate on olivine surface : Implications to formation of Martian’s regolith
- 2020
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 512
-
Tidskriftsartikel (refereegranskat)abstract
- Perchlorates have been found widespread on the surface of Mars, their origin and degradation pathways are not understood to date yet. We investigate here, from a theoretical point of view, the potential redox processes that take place in the interaction of Martian minerals such as olivine, with anhydrous and hydrated perchlorates. For this theoretical study, we take as mineral substrate the (1 0 0) surface of forsterite and calcium perchlorate salt as adsorbate. Our DFT calculations suggests a reduction pathway to chlorate and chlorite. When the perchlorate has more than 4 water molecules, this mechanism, which does not require high-temperature or high energy sources, results in parallel with the oxidation of the mineral surface, forming magnesium peroxide, MgO2, and in the formation of ClO3, which through photolysis is known to form ClO-O2. Because of the high UV irradiance that reaches the surface of Mars, this may be a source of O2 on Mars. Our results suggest that this process may be a natural removal pathway for perchlorates from the Martian regolith, which in the presence of atmospheric water for salt hydration, can furthermore lead to the production of oxygen. This mechanism may thus have implications on the present and future habitability of the Martian surface.
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| 17. |
- Fonseca, Ricardo, et al.
(författare)
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A surface temperature and moisture intercomparison study of the Weather Research and Forecasting model, in‐situ measurements and satellite observations over the Atacama Desert
- 2019
-
Ingår i: Quarterly Journal of the Royal Meteorological Society. - : John Wiley & Sons. - 0035-9009 .- 1477-870X. ; 145:722, s. 2202-2220
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Tidskriftsartikel (refereegranskat)abstract
- Good knowledge of the environmental conditions of deserts on Earth is relevant forclimate studies. The Atacama Desert is of particular interest as it is considered tobe the driest region on Earth. We have performed simulations using the WeatherResearch and Forecasting (WRF) model over the Atacama Desert for two week-longperiods in the austral winter season coincident with surface temperature and relativehumidity in-situ observations at three sites. We found that the WRF model generallyoverestimates the daytime surface temperature, with biases of up to 11◦C, despitegiving a good simulation of the relative humidity. In order to improve the agree-ment with observed measurements, we conducted sensitivity experiments in whichthe surface albedo, soil moisture content and five tuneable parameters in the NoahLand Surface Model (namely soil porosity, soil suction, saturated soil hydraulic con-ductivity, thebparameter used in hydraulic functions and the quartz fraction) areperturbed. We concluded that an accurate simulation is not possible, most likelybecause the Noah Land Surface Model does not have a groundwater table that maybe shallow in desert regions. The WRF-predicted land surface temperature is alsoevaluated against that estimated from the Moderate Resolution Imaging Spectrora-diometer (MODIS) instrument. While at night the satellite-derived and ground-basedmeasurements are generally in agreement, during the day MODIS estimates aretypically lower by as much as 17◦C. This is attributed to the large uncertainty inthe MODIS-estimated land surface temperatures in arid and semi-arid regions. Thefindings of this work highlight the need for ground-based observational networksin remote regions such as the Atacama Desert where satellite-derived and modelproducts may not be very accurate.
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| 18. |
- Fonseca, Ricardo Morais, et al.
(författare)
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MARSWRF Prediction of Entry Descent Landing Profiles : Applications to Mars Exploration
- 2019
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Ingår i: Earth and Space Science. - : John Wiley & Sons. - 2333-5084. ; 6:8, s. 1440-1459
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we use the Mars implementation of the Planet Weather Research and Forecasting model, MarsWRF, to simulate the Entry, Descent and Landing (EDL) vertical profiles from six past missions: Pathfinder, Mars Exploration Rovers Opportunity and Spirit, Phoenix, Mars Science Laboratory Curiosity rover and ExoMars 2016 (Schiaparelli), and compare the results with observed data. In order to investigate the sensitivity of the model predictions to the atmospheric dust distribution, MarsWRF is run with two prescribed dust scenarios. It is concluded that the MarsWRF EDL predictions can be used for guidance into the design and planning stage of future missions to the planet, as it generally captures the observed EDL profiles, although it has a tendency to underestimate the temperature and overestimate the density for heights above 15 km. This could be attributed to an incorrect representation of the observed dust loading. We have used the model to predict the EDL conditions that may be encountered by two future missions: ExoMars 2020 and Mars 2020. When run for Oxia Planum and Jezero Crater for the expected landing time, MarsWRF predicts a large sensitivity to the dust loading in particular for the horizontal wind speed above 10‐15 km with maximum differences of up to ±30 m s‐1 for the former and ±15 m s‐1 for the latter site. For both sites, the best time for EDL, i.e. when the wind speed is generally the weakest with smaller shifts in direction, is predicted to be in the late morning and early afternoon.
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| 19. |
- Fonseca, Ricardo, et al.
(författare)
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Planetary Boundary Layer and Circulation Dynamics at Gale Crater, Mars
- 2018
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Ingår i: Icarus. - : Elsevier. - 0019-1035 .- 1090-2643. ; 302, s. 537-559
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Tidskriftsartikel (refereegranskat)abstract
- The Mars implementation of the Planet Weather Research and Forecasting (PlanetWRF) model, MarsWRF, is used here to simulate the atmospheric conditions at Gale Crater for different seasons during a period coincident with the Curiosity rover operations. The model is first evaluated with the existing single-point observations from the Rover Environmental Monitoring Station (REMS), and is then used to provide a larger scale interpretation of these unique measurements as well as to give complementary information where there are gaps in the measurements.The variability of the planetary boundary layer depth may be a driver of the changes in the local dust and trace gas content within the crater. Our results show that the average time when the PBL height is deeper than the crater rim increases and decreases with the same rate and pattern as Curiosity's observations of the line-of-sight of dust within the crater and that the season when maximal (minimal) mixing is produced is Ls 225°-315° (Ls 90°-110°). Thus the diurnal and seasonal variability of the PBL depth seems to be the driver of the changes in the local dust content within the crater. A comparison with the available methane measurements suggests that changes in the PBL depth may also be one of the factors that accounts for the observed variability, with the model results pointing towards a local source to the north of the MSL site.The interaction between regional and local flows at Gale crater is also investigated assuming that the meridional wind, the dynamically important component of the horizontal wind at Gale, anomalies with respect to the daily mean can be approximated by a sinusoidal function as they typically oscillate between positive (south to north) and negative (north to south) values that correspond to upslope/downslope or downslope/upslope regimes along the crater rim and Mount Sharp slopes and the dichotomy boundary. The smallest magnitudes are found in the northern crater floor in a region that comprises Bradbury Landing, in particular at Ls 90° when they are less than 1 m s−1, indicating very little lateral mixing with outside air. The largest amplitudes occur in the south-western portions of the crater where they can exceed 20 m s−1. Should the slope flows along the crater rims interact with the dichotomy boundary flow, which is more likely at Ls 270° and very unlikely at Ls 90°, they are likely to interact constructively for a few hours from late evening to nighttime (∼17-23 LMST) and from pre-dawn early morning (∼5-11 LMST) hours at the norther crater rim and destructively at night (∼22-23 LMST) and in the morning (∼10-11 LMST) at the southern crater rim.We conclude that a better understanding of the PBL and circulation dynamics has important implications for the variability of the concentration of dust, non-condensable and trace gases at the bottom of other craters on Mars as mixing with outside air can be achieved vertically, through changes in the PBL depth, and laterally, by the transport of air into and out of the crater.
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| 20. |
- G. Trainer, Melissa, et al.
(författare)
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Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars
- 2019
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Ingår i: Journal of Geophysical Research - Planets. - : John Wiley & Sons. - 2169-9097 .- 2169-9100. ; 124:11, s. 3000-3024
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Tidskriftsartikel (refereegranskat)abstract
- The Sample Analysis at Mars (SAM) instrument onboard the Mars Science Laboratory Curiosity rover measures the chemical composition of major atmospheric species (CO2, N2, 40Ar, O2, and CO) through a dedicated atmospheric inlet. We report here measurements of volume mixing ratios in Gale Crater using the SAM quadrupole mass spectrometer, obtained over a period of nearly 5 years (3 Mars years) from landing. The observation period spans the northern summer of MY 31 and solar longitude (LS) of 175° through spring of MY 34, LS = 12°. This work expands upon prior reports of the mixing ratios measured by SAM QMS in the first 105 sols of the mission. The SAM QMS atmospheric measurements were taken periodically, with a cumulative coverage of four or five experiments per season on Mars. Major observations include the seasonal cycle of CO2, N2, and Ar, which lags approximately 20–40° of LS behind the pressure cycle driven by CO2 condensation and sublimation from the winter poles. This seasonal cycle indicates that transport occurs on faster timescales than mixing. The mixing ratio of O2 shows significant seasonal and interannual variability, suggesting an unknown atmospheric or surface process at work. The O2 measurements are compared to several parameters, including dust optical depth and trace CH4 measurements by Curiosity. We derive annual mean volume mixing ratios for the atmosphere in Gale Crater: CO2 = 0.951 (±0.003), N2 = 0.0259 (±0.0006), 40Ar = 0.0194 (±0.0004), O2 = 1.61 (±0.09) x 10‐3, and CO = 5.8 (±0.8) x 10‐4.
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| 21. |
- Galvez-Martinez, Santos, et al.
(författare)
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Ar+ ion bombardment dictates glycine adsorption on pyrite (100) surface : X-ray photoemission spectroscopy and DFT approach
- 2020
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 530
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Tidskriftsartikel (refereegranskat)abstract
- Ar+ ion sputtering on pyrite surfaces leads to the generation of sulfur vacancies and metallic iron. Our research shows that sputtering and annealing processes drive electrostatic changes on the pyrite surface, which play an important role in the molecular adsorption of glycine. While both chemical species (anion and zwitterion) adsorb on a sputtered pyrite surface, the anionic form of glycine is favoured. Nevertheless, in both treatments (sputtered or annealed surfaces), molecules evolve from zwitterionic to anionic species over time. Quantum mechanical calculations based in Density Functional Theory (DFT) suggest the energy required to generate vacancies increases with the number of vacancies produced, and the atomic charge of the Fe atoms that is next to a vacancy increases linearly with the number of vacancies. This leads to enhanced redox processes on the sputtered pyrite surface that favour the adsorption of glycine, which is confirmed experimentally by X-ray Photoemission Spectroscopy (XPS). We have investigated theoretically the efficiency of the adsorption process of the zwitterionic glycine onto vacancies sites: this reaction is exothermic, i.e. is energetically favoured and its energy increases with the number of defects, confirming the increased reactivity observed experimentally. The experiments show a treatment-dependent molecular selectivity of the pyrite surface.
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| 22. |
- Galvez-Martinez, Santos, et al.
(författare)
-
Defects on a pyrite(100) surface produce chemical evolution of glycine under inert conditions : experimental and theoretical approaches
- 2019
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 21:44, s. 24535-24542
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of non-stoichiometric sites on the pyrite(100) surface makes it a suitable substrate for driving the chemical evolution of the amino acid glycine over time, even under inert conditions. Spectroscopic molecular fingerprints prove a transition process from a zwitterionic species to an anionic species over time on the monosulfide enriched surface. By combining experimental and theoretical approaches, we propose a surface mechanism where the interaction between the amino acid species and the surface will be driven by the quenching of the surface states at Fe sites and favoured by sulfur vacancies. This study demonstrates the potential capability of pyrite to act as a surface catalyst.
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| 23. |
- Gebhardt, C., et al.
(författare)
-
Characterizing Dust‐Radiation Feedback and Refining the Horizontal Resolution of the MarsWRF Model down to 0.5 Degree
- 2021
-
Ingår i: Journal of Geophysical Research - Planets. - : John Wiley & Sons. - 2169-9097 .- 2169-9100. ; 126:3
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, three simulations by the Mars Weather Research and Forecasting (MarsWRF) model are compared: two 10 Martian Year (MY) 2° × 2° simulations with (i) fully radiatively‐active dust and (ii) a prescribed dust scenario, and a (iii) 1 MY 0.5° × 0.5° simulation with prescribed dust as in (ii). From comparing (i) and (ii), we found that the impact of dust‐radiation feedback is individually different for any region. The most striking evidence are major dust lifting activities to the south of Chryse Planitia (S‐CP) seen in (i) but not in (ii). By contrast, dust lifting and deposition on the southern slopes and inside the Hellas Basin are similar in both simulations. The latter, in turn, points towards a similar near‐surface atmospheric circulation. In (iii), the total global amount of wind stress lifted dust is by a factor of ∼8 higher than in (ii), with S‐CP being a major lifting region as in (i). Nonetheless, the surface dust lifting by wind stress in (iii) may be also reduced regionally, as seen at the peak of Elysium Mons because of its unique topography. The zonal mean circulation in (i) is generally of a comparable strength to that in (ii), with exceptions in global dust storm years, when it is clearly stronger in (i), in line with a dustier atmosphere. The differences in the zonal mean circulation between (ii) and (iii) are mostly at lower altitudes, and may arise due to differences in the representation of the topography.
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| 24. |
- Guzewich, Scott D., et al.
(författare)
-
Mars Science Laboratory Observations of the 2018/Mars Year 34 Global Dust Storm
- 2019
-
Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 46:1, s. 71-79
-
Tidskriftsartikel (refereegranskat)abstract
- Mars Science Laboratory Curiosity rover observations of the 2018/Mars year 34 global/planet‐encircling dust storm represent the first in situ measurements of a global dust storm with dedicated meteorological sensors since the Viking Landers. The Mars Science Laboratory team planned and executed a science campaign lasting approximately 100 Martian sols to study the storm involving an enhanced cadence of environmental monitoring using the rover's meteorological sensors, cameras, and spectrometers. Mast Camera 880‐nm optical depth reached 8.5, and Rover Environmental Monitoring Station measurements indicated a 97% reduction in incident total ultraviolet solar radiation at the surface, 30K reduction in diurnal range of air temperature, and an increase in the semidiurnal pressure tide amplitude to 40 Pa. No active dust‐lifting sites were detected within Gale Crater, and global and local atmospheric dynamics were drastically altered during the storm. This work presents an overview of the mission's storm observations and initial results.
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| 25. |
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| 26. |
- Guzewich, Scott D., et al.
(författare)
-
The Vertical Dust Profile over Gale Crater, Mars
- 2017
-
Ingår i: Journal of Geophysical Research - Planets. - : American Geophysical Union (AGU). - 2169-9097 .- 2169-9100. ; 122:12, s. 2779-2792
-
Tidskriftsartikel (refereegranskat)abstract
- We create a vertically coarse, but complete, vertical profile of dust mixing ratio from the surface to the upper atmosphere over Gale Crater, Mars, using the frequent joint atmospheric observations of the orbiting Mars Climate Sounder (MCS) and the Mars Science Laboratory (MSL) Curiosity rover. Using these data and an estimate of planetary boundary layer (PBL) depth from the MarsWRF general circulation model, we divide the vertical column into three regions. The first region is the Gale Crater PBL, the second is the MCS-sampled region, and the third is between these first two. We solve for a well-mixed dust mixing ratio within this third (middle) layer of atmosphere to complete the profile.We identify a unique seasonal cycle of dust within each atmospheric layer. Within the Gale PBL, dust mixing ratio maximizes near southern hemisphere summer solstice (Ls = 270°) and minimizes near winter solstice (Ls = 90-100°) with a smooth sinusoidal transition between them. However, the layer above Gale Crater and below the MCS-sampled region more closely follows the global opacity cycle and has a maximum in opacity near Ls = 240° and exhibits a local minimum (associated with the “solsticial pause” in dust storm activity) near Ls = 270°. With knowledge of the complete vertical dust profile, we can also assess the frequency of high-altitude dust layers over Gale. We determine that 36% of MCS profiles near Gale Crater contain an “absolute” high-altitude dust layer wherein the dust mixing ratio is the maximum in the entire vertical column.
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| 27. |
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| 28. |
- Konatham, Samuel, 1992-
(författare)
-
Atmospheric Species and Spectral Radiation in Terrestrial Exoplanets : Implications for Astrobiology
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The physical properties of the planets and their parent stars are fundamental in the composition of atmospheres and radiative environments, which fundamentally determine their surface temperature and habitability. The atmospheric composition and radiation play a vital role in the emergence of life. This doctoral thesis presents two main results: 1. A method that uses the physical properties of the planets and their parent stars to infer the potential atmospheric compositions of the known exoplanets. For that, fundamental physics concepts and the basics of the kinetic theory of gases are used. Additionally, a new list of potentially habitable exoplanets is presented based on the resulting atmospheric compositions and the criteria that Earth-like atmospheres that can host liquid water should be considered habitable. The presented method also provides a preliminary classification of exoplanets similar to Earth (in terms of atmosphere) and their potential habitability. 2. A study of the impact of the radiation environment on the development and evolution of the human visual system towards optimal use of the available radiation. Human vision's possible evolutionary directions are presented while overcoming the shortcomings in the existing studies. The human visual system is hypothesised to have evolved in conjugation with the prevailing spectral radiation environment for photopic (daytime) and scotopic (night-time). One of the main novelties of this study is the comparison of the human vision bandwidth with the Full Width at half-maximum (FWHM) of the radiation reaching the shallow depths of the ocean, which may suggest that this is optimized for the development of animal sight during the formation of the early proto-visual system. Moreover, the observed maximum absorption wavelength during photopic vision (555nm) correlates with the maximum total energy for a 300 nm vision bandwidth. Furthermore, the analysis of the radiation environment at different solar zenith angles (SZA) during dusk suggests that the scotopic vision evolved to optimize information retrieval during these hours. The work presented in this thesis contributes to perform screening of Earth-like exoplanets and the study of astrobiological or space exploration aspects such as potential habitability, human-like vision, photosynthesis efficiency and evolution of life systems on exoplanets.
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| 29. |
- Korablev, Oleg I., et al.
(författare)
-
Infrared Spectrometer for ExoMars: A Mast-Mounted Instrument for the Rover
- 2017
-
Ingår i: Astrobiology. - : Mary Ann Liebert. - 1531-1074 .- 1557-8070. ; 17:6-7, s. 542-564
-
Tidskriftsartikel (refereegranskat)abstract
- ISEM (Infrared Spectrometer for ExoMars) is a pencil-beam infrared spectrometer that will measure reflected solar radiation in the near infrared range for context assessment of the surface mineralogy in the vicinity of the ExoMars rover. The instrument will be accommodated on the mast of the rover and will be operated together with the panoramic camera (PanCam), high-resolution camera (HRC). ISEM will study the mineralogical and petrographic composition of the martian surface in the vicinity of the rover, and in combination with the other remote sensing instruments, it will aid in the selection of potential targets for close-up investigations and drilling sites. Of particular scientific interest are water-bearing minerals, such as phyllosilicates, sulfates, carbonates, and minerals indicative of astrobiological potential, such as borates, nitrates, and ammonium-bearing minerals. The instrument has an ∼1° field of view and covers the spectral range between 1.15 and 3.30 μm with a spectral resolution varying from 3.3 nm at 1.15 μm to 28 nm at 3.30 μm. The ISEM optical head is mounted on the mast, and its electronics box is located inside the rover's body. The spectrometer uses an acousto-optic tunable filter and a Peltier-cooled InAs detector. The mass of ISEM is 1.74 kg, including the electronics and harness. The science objectives of the experiment, the instrument design, and operational scenarios are described.
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| 30. |
- Korablev, Oleg, et al.
(författare)
-
No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations
- 2019
-
Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 568, s. 517-520
-
Tidskriftsartikel (refereegranskat)abstract
- The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today1. A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations2,3,4,5. These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere6,7, which—given methane’s lifetime of several centuries—predicts an even, well mixed distribution of methane1,6,8. Here we report highly sensitive measurements of the atmosphere of Mars in an attempt to detect methane, using the ACS and NOMAD instruments onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter from April to August 2018. We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections2,4. We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater4 would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally.
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| 31. |
- Lanza, Nina L., et al.
(författare)
-
Oxidation of manganese in an ancient aquifer, Kimberley formation, Gale crater, Mars
- 2016
-
Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 43:14, s. 7398-7407
-
Tidskriftsartikel (refereegranskat)abstract
- The Curiosity rover observed high Mn abundances (>25wt % MnO) in fracture-filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars. The correlation between Mn and trace metal abundances plus the lack of correlation between Mn and elements such as S, Cl, and C, reveals that these deposits are Mn oxides rather than evaporites or other salts. On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions; hence, these findings suggest that similar processes occurred on Mars. Based on the strong association between Mn-oxide deposition and evolving atmospheric dioxygen levels on Earth, the presence of these Mn phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day
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| 32. |
- Lasue, J., et al.
(författare)
-
Martian Eolian Dust Probed by ChemCam
- 2018
-
Ingår i: Geophysical Research Letters. - : John Wiley & Sons. - 0094-8276 .- 1944-8007. ; 45:20, s. 10968-10977
-
Tidskriftsartikel (refereegranskat)abstract
- The ubiquitous eolian dust on Mars plays important roles in the current sedimentary and atmospheric processes of the planet. The ChemCam instrument retrieves a consistent eolian dust composition at the submillimeter scale from every first laser shot on Mars targets. Its composition presents significant differences with the Aeolis Palus soils and the Bagnold dunes as it contains lower CaO and higher SiO2. The dust FeO and TiO2contents are also higher, probably associated with nanophase oxide components. The dust spectra show the presence of volatile elements (S and Cl), and the hydrogen content is similar to Bagnold sands but lower than Aeolis Palus soils. Consequently, the dust may be a contributor to the amorphous component of soils, but differences in composition indicate that the two materials are not equivalent.
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| 33. |
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| 34. |
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| 35. |
- Martin-Torres, Javier, et al.
(författare)
-
Brine-Induced Tribocorrosion Accelerates Wear on Stainless Steel: Implications for Mars Exploration
- 2021
-
Ingår i: Advances in Astronomy. - : Hindawi Publishing Corporation. - 1687-7969 .- 1687-7977. ; 2021
-
Tidskriftsartikel (refereegranskat)abstract
- Tribocorrosion is a degradation phenomenon of material surfaces subjected to the combined action of mechanical loading and corrosion attack caused by the environment. Although corrosive chemical species such as materials like chloride atoms, chlorides, and perchlorates have been detected on the Martian surface, there is a lack of studies of its impact on materials for landed spacecraft and structures that will support surface operations on Mars. Here, we present a series of experiments on the stainless-steel material of the ExoMars 2020 Rosalind Franklin rover wheels. We show how tribocorrosion induced by brines accelerates wear on the materials of the wheels. Our results do not compromise the nominal ExoMars mission but have implications for future long-term surface operations in support of future human exploration or extended robotic missions on Mars.
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| 36. |
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| 37. |
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| 38. |
- Martorell, José Antonio Gordillo, et al.
(författare)
-
The Infinite Learning Chain. Flipped Professional Labs for Learning and Knowledge Co-Creation
- 2019
-
Ingår i: Open Education Studies. - : Walter de Gruyter. - 2544-7831. ; 1, s. 151-176
-
Tidskriftsartikel (refereegranskat)abstract
- Nowadays universities and other classical research institutions are changing their role in knowledge creation. In general terms we can characterize this transition as the path from "Closed Science"to "Open Science"as a part of a deeper and structural phenomenon known as "knowledge democratization", where different stakeholders as students, makers and other tech and science enthusiasts are able to create knowledge learning from the researchers and cooperating with them. In this process, science engagement of these new actors is a key point to stimulate their creativity, get some important research skills learnt directly from the researchers and be able to apply these skills teaching others in a continuous "learning chain". In this article, we introduce some main features and preliminary results of an experiment called "The infinite learning chain"done in cooperation with Arduino, focused on sensing science and based in a real research project of Group of Atmospheric Science (GAS) called Luleå Environmental Monitoring Stations (LEMS). We debate some interesting questions related to the impact of the format in terms of science engagement, STEM skills acquisition and cooperative learning involvement. We used as "learning ecosystem"a professional Lab, the INSPIRE Lab a complete multidisciplinary facility for space and environmental research and exploration.
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| 39. |
- Mateo-Marti, E., et al.
(författare)
-
Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life
- 2019
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- The molecular form of nitrogen, N2, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m 2 of ultraviolet irradiance in the 200–400 nm range. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface.
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| 40. |
- Mathanlal, Thasshwin
(författare)
-
Development of robotic instruments and techniques for space and astrobiological exploration and research
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Astrobiology is the study of life in the universe. The search for life beyond the Earth requires an understanding of the signatures of life, and of the nature of the environments that support it. Space exploration is a crucial factor to achieve these goals. The PhD thesis focusses on developing novel techniques for astrobiological and Earth exploration. It includes instrument prototyping, validation and calibration of a flight-ready space in-strument.This thesis explains the development of four instruments namely 1) KORE – a robotic exploration rover designed for subsurface analogue planetary explorations; 2) InXSpace3D – a 3D mapping payload for biogeomorphological analysis based on a com-mercial RGB-D camera and an open-source algorithm; 3) S3ME2 – a self-sustainable environmental monitoring station capable of withstanding harsh environments on Earth; and 4) PACKMAN – a space weather monitoring instrument. The instruments are devoted to: 1) the spatial exploration and characterization (KORE and InXSpace3D) of a potentially habitable environment and 2) the monitorization of the rapidly vary-ing environmental variables that may affect life (S3ME2 and PACKMAN), its evolution and preservation. The instruments are developed according to the Technology Readiness Level (TRL) Ladder and a cost and time effective methodology which maximizes the use of Commercial Off-The-Shelf (COTS) components and Open source software.The thesis also discusses the bioburden sterilization and control procedure of some of the sensors on the flight-ready space Instrument HABIT (HabitAbility: Brines, Irradi-ation and Temperature), that will be part of the ExoMars 2022 mission. Again, a COTS and an open source software-based approach has been used in these higher TRL level procedures. This demonstrates the fact that such an engineering approach can benefit the scientific community by developing instruments with a minimal investment of time and resources without compromising the scientific quality of the instrument. The thesis concludes with the adaptation of the research methodology to adapt space technologies that are applicable in space for human support systems to address an emerging problem on Earth: ATMO-Vent, a low-cost COTS-based ventilator that produces an adapted breathable atmosphere for COVID-19 patients.During the PhD thesis, the author has published five peer-reviewed journal papers, two peer-reviewed conference abstracts and two co-authored peer-reviewed journal pa-pers. The first authored papers and conference abstracts have been appended to the Part-II of the thesis.
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| 41. |
- Mathanlal, Thasshwin, et al.
(författare)
-
PACKMAN - Portable Instrument to Study Space Weather
- 2018
-
Ingår i: IAC-18. - : International Astronautical Federation.
-
Konferensbidrag (refereegranskat)abstract
- The Earth’s atmosphere is continuously bombarded by energetic charged particles from space. To date, there is a missing gap of information regarding the amount, energy, time variability, and type of space radiation that reaches the lower layers of the atmosphere, as well as on its geographic and altitude distribution and the implications on infrastructures and climate. To generate a long-time, multiple-site, open-access record of space radiation on Earth we designed an open source, autonomous instrument, called PACKMAN (PArticle Counter k-index Magnetic ANomaly), with Commercial Off-The-Shelf (COTS) components.PACKMAN is a robust and light scalable instrument that monitors gamma, beta, alpha radiation and muons and includes environmental sensors to monitor pressure, temperature, relative humidity, and magnetic perturbations. PACKMAN has demonstrated its operability at different latitudes and atmospheric heights (in balloons). As of today, several PACKMAN units have been installed and have operated already at multiple latitudes: 1) Space campus LTU, Kiruna, Sweden (67.84N, 20.41E, 390 m); 2) LTU Main campus, Luleå, Sweden (65.62N, 22.14E, 15 m); 3) University of Edinburgh, United Kingdom (55.94N, 3.19W, 98 m); 4) Boulby Mine, United Kingdom (54.56N, 0.82W, 93 m and -1.1 km). Finally, two PACKMAN units have been flown in balloons to the stratosphere: 5) Cordoba airport, Cordoba, Spain (37.84N, 4.84W, 90 m to 27 km); 6) Esrange Space Center, Sweden (67.88N, 21.12E, 328 m to 27 km). In this work, we present the design and operation of these instruments, and summarize the main scientific discoveries. The data are compared to various ground based and orbiter instruments such as the Geostationary Operational Environmental Satellite (GOES).The observations acquired by PACKMAN will be used to provide open access, real time information, for: 1) education and public awareness of space weather phenomena; 2) to compare with Earth climate observations; 3) to provide real-time information of space weather variability for potential damage to infrastructures (telecommunications, power generation facilities, aviation, transport, etc.); 4) to monitor natural radiation sources at multiple environments; 5) to monitor the variability of the Pfotzer maximum height during different stages of solar activity and seasons and 6) finally, this project may serve as a reference for future scalable networks where multiple instruments are deployed at different sites or conditions and with different initiation times, and where the informational value increases by adhering to a common PDS4 format and analysing the data in a concurrent way.
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| 42. |
- Mathanlal, Thasshwin, et al.
(författare)
-
Self-Sustainable Monitoring Station for Extreme Environments (S3ME2): Design and validation
- 2019
-
Ingår i: 2018 Second International Conference on Green Computing and Internet of Things (ICGCIoT). - : IEEE. - 9781538656570 ; , s. 240-245
-
Konferensbidrag (refereegranskat)abstract
- We describe the development of a robust, self-sustainable, versatile environmental monitoring station, the S3ME2, with a multitude of sensors capable of operating in extreme environments (from cold arid sub-arctic regions to hot deserts and high-altitude mountain terrains), providing realtime quality data of critical climate and geophysical parameters for a wide field of research such as pressure, surface and subsurface temperature and humidity, magnetic field and seismic activity. The dedicated communication modem utilizes IoT technology and can deliver this data from remote regions. The S3ME2 has been designed as a low-cost instrument to facilitate the production of multiple units. During the pilot phase, it has demonstrated continuous operability for up to 6 months, including survival during extremely cold, snowy, and low insolation, and low wind periods in the Sub-Arctic region. With its robust design, S3ME2 exploits the use of renewable sources of energy such as solar and wind power to power the system. The S3ME2 has also been designed from a modular point of view with commercial off the shelf components (COTS) and open source hardware, considering long term operability of the station. The sensor modules can be easily added, replaced, or upgraded such that a stable functioning of the system is guaranteed.
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| 43. |
- Mathanlal, Thasshwin, et al.
(författare)
-
Subsurface robotic exploration for geomorphology, astrobiology and mining during MINAR6 campaign, Boulby Mine, UK : part II (Results and Discussion)
- 2021
-
Ingår i: International Journal of Astrobiology. - : Cambridge University Press. - 1473-5504 .- 1475-3006. ; 20:1, s. 93-108
-
Tidskriftsartikel (refereegranskat)abstract
- Geomorphological studies of the hidden and protected subsurface environments are crucial to obtain a greater insight into the evolution of planetary landforms, hydrology, climate, geology and mineralogy. From an astrobiological point of view subsurface environments are of interest for their potential habitability as they are local environments that are partially or fully shielded from the high levels of space and solar radiation. Furthermore, in the case of Mars, there is an increasing interest in searching for the presence of past or extant life in its subsurface. These applications make it mandatory to investigate equipment and instrumentation that allow for the study of subsurface geomorphology, as well as organic chemical biomarkers, such as biomolecules, carbon, nitrogen and sulphur isotopes, and other biologically significant minerals and gases. Mines on Earth can be used as analogues to investigate the geomorphology of Martian subsurface environments and perform astrobiology studies. With that goal, we have developed a low-cost, robust, remotely operable subsurface rover called KORE (KOmpact Rover for Exploration). This work illustrates the studies of a terrestrial analogue for the exploration of Mars using KORE during the Mine Analogue Research 6 (MINAR 6) campaign with the low-cost 3D mapping technology InXSpace 3D (In situ 3D mapping tool eXploration of space 3D). InXSpace 3D utilizes an RGB-D camera that captures depth information in addition to the RGB data of an image, operating based on the structured light principle capable of providing depth information in mm scale resolution at sub 3 m mapping range. InXSpace 3D is used to capture point clouds of natural and artificial features, thereby obtaining information about geologically relevant structures and also to incorporate them in earth mining safety. We tested two of the dense simultaneous localization and mapping (SLAM) algorithms: Kintinuous and Real-Time Appearance-Based Mapping (RTAB-Map) to check the performance of InXSpace 3D in a dark mine environment. Also, the air accumulation of volatiles such as methane and formaldehyde due to thermogenic and mining process was measured with the environmental station payload on the rover platform, which caters to both astrobiological significance and mine safety. The main conclusions of this work are: (1) a comparison made between the RTAB-Map algorithm and Kintinuous algorithm showed the superiority of Kintinuous algorithm in providing better 3D reconstruction; although RTAB-Map algorithm captured more points than the Kintinuous algorithm in the dark mine environment; (2) a comparison of point cloud images captured with and without lighting conditions had a negligible effect on the surface density of the point clouds; (3) close-range imaging of the polygonal features occurring on the halite walls using InXSpace 3D provided mm-scale resolution to enable further characterization; (4) heuristic algorithms to quickly post-process the 3D point cloud data provided encouraging results for preliminary analyses; (5) we successfully demonstrated the application of KORE to mine safety; and (6) the multi-sensors platform on KORE successfully monitored the accumulated volatiles in the mine atmosphere during its operation. The findings obtained during this KORE campaign could be incorporated in designing and planning future subsurface rover explorations to potential planetary bodies such as Mars with synergistic applications to subsurface environments in mines on Earth.
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| 44. |
- Mompeán, C., et al.
(författare)
-
Prebiotic chemistry in neutral/reduced-alkaline gas-liquid interfaces
- 2019
-
Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- The conditions for the potential abiotic formation of organic compounds from inorganic precursors have great implications for our understanding of the origin of life on Earth and for its possible detection in other environments of the Solar System. It is known that aerosol-interfaces are effective at enhancing prebiotic chemical reactions, but the roles of salinity and pH have been poorly investigated to date. Here, we experimentally demonstrate the uniqueness of alkaline aerosols as prebiotic reactors that produce an undifferentiated accumulation of a variety of multi-carbon biomolecules resulting from high-energy processes (in our case, electrical discharges). Using simulation experiments, we demonstrate that the detection of important biomolecules in tholins increases when plausible and particular local planetary environmental conditions are simulated. A greater diversity in amino acids, carboxylic acids, N-heterocycles, and ketoacids, such as glyoxylic and pyruvic acid, was identified in tholins synthetized from reduced and neutral atmospheres in the presence of alkaline aqueous aerosols than that from the same atmospheres but using neutral or acidic aqueous aerosols.
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| 45. |
- Navarro‐González, Rafael, et al.
(författare)
-
Abiotic Input of Fixed Nitrogen by Bolide Impacts to Gale Crater During the Hesperian : Insights From the Mars Science Laboratory
- 2019
-
Ingår i: Journal of Geophysical Research - Planets. - : John Wiley & Sons. - 2169-9097 .- 2169-9100. ; 124:1, s. 94-113
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular hydrogen (H2) from volcanic emissions is suggested to warm the Martian surface when carbon dioxide (CO2) levels dropped from the Noachian (4100 to 3700 Myr) to the Hesperian (3700 to 3000 Myr). Its presence is expected to shift the conversion of molecular nitrogen (N2) into different forms of fixed nitrogen (N). Here we present experimental data and theoretical calculations that investigate the efficiency of nitrogen fixation by bolide impacts in CO2‐N2 atmospheres with or without H2. Surprisingly, nitric oxide (NO) was produced more efficiently in 20% H2 in spite of being a reducing agent and not likely to increase the rate of nitrogen oxidation. Nevertheless, its presence led to a faster cooling of the shock wave raising the freeze‐out temperature of NO resulting in an enhanced yield. We estimate that the nitrogen fixation rate by bolide impacts varied from 7 × 10−4 to 2 × 10−3 g N·Myr−1·cm−2 and could imply fluvial concentration to explain the nitrogen (1.4 ± 0.7 g N·Myr−1·cm−2) detected as nitrite (NO2−) and nitrate (NO3−) by Curiosity at Yellowknife Bay. One possible explanation is that the nitrogen detected in the lacustrine sediments at Gale was deposited entirely on the crater's surface and was subsequently dissolved and transported by superficial and ground waters to the lake during favorable wet climatic conditions. The nitrogen content sharply decreases in younger sediments of the Murray formation suggesting a decline of H2 in the atmosphere and the rise of oxidizing conditions causing a shortage in the supply to putative microbial life.
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| 46. |
- Nazarious, Miracle Israel, 1992-
(författare)
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Scientific Instruments to Facilitate the Human Exploration of Mars
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This PhD thesis describes, from an engineering perspective, some of the preliminary steps that need to be implemented to facilitate the human exploration of Mars. It focuses on the development of a set of novel scientific or technology demonstrator instruments. The engineering problem starts with a conceptual idea and the definition of individual functional requirements, that may be related to scientific or technological objectives. To solve this problem, an unique approach adapted during this thesis, allowed for designing and building efficiently, testing and refining the instruments in multiple iterations using simple techniques like 3-D printing, breadboard prototyping and low-cost commercial off the shelf (COTS) components. This approach reduces the cost and facilitates the accessibility of space instrument design and testing to a broader community. The steps include demonstrating the operability of the concept with prototypes, calibrating the responses and validating their operation in representative environments, thereby raising the technology readiness level (TRL) of the instrument with a lower investment in time and resources than traditional approaches that use specialized components and fabrica-tion techniques.The thesis provides a detailed description of the design and development process, and discusses the calibration and validation results of four different instruments, namely: 1) Brine Observation Transition To Liquid Experiment (BOTTLE) as a part of HabitAbil-ity: Brines, Irradiation and Temperature (HABIT) instrument onboard the ESA/IKI’s ExoMars 2022 Surface Platform Kazachok, for investigating the surface environmen-tal conditions and demonstrating the capability of salts to absorb water on Mars, 2) Metabolt, a small-sized portable incubator to monitor the behaviour of the microbiome in soils, which will be a critical element of future greenhouses on Mars or the Moon, 3) Methanox, an in-situ resource utilization demonstrator for converting local resources on Mars and producing methane and ammonia as space fuel, and 4) PRessure Optimized PowEred Respirator (PROPER), a wearable cleanroom developed for protecting the hu-mans against biological pathogens, showing the direct applicability of this research to solve Earth-based problems. During the final phase of the PhD thesis, the world suffered the COVID-19 pandemic. This challenge provided an opportunity to test the approach presented in this thesis and inspired the development of this equipment, and may also be of relevance to protect from biological cross-contamination in planetary habitats and laboratories while handling local regolith materials and samples on Mars.This work also highlights the calibration of the HABIT Flight Model (FM) in the cleanroom of Omnisys Instruments AB, Sweden, defines the retrieval models that will be used during ExoMars 2022 mission operations and data archiving in the Planetary Science Archive (PSA). Parts of this thesis were already published in the form of peer-reviewed journal articles and conference abstracts.
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| 47. |
- Sam, Lydia, et al.
(författare)
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Small Lava Caves as Possible Exploratory Targets on Mars : Analogies Drawn from UAV Imaging of an Icelandic Lava Field
- 2020
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Ingår i: Remote Sensing. - : MDPI. - 2072-4292. ; 12:12
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Tidskriftsartikel (refereegranskat)abstract
- Volcanic-aeolian interactions and processes have played a vital role in landscape evolution on Mars. Martian lava fields and associated caves have extensive geomorphological, astrobiological, and in-situ resource utilization (ISRU) implications for future Mars missions which might be focused on subsurface exploration. Although several possible cave “skylights” of tens to >100 m diameter have been spotted in lava fields of Mars, there is a possibility of prevalence of meter-scale features which are an order of magnitude smaller and difficult to identify but could have vital significance from the scientific and future exploration perspectives. The Icelandic volcanic-aeolian environment and fissure volcanoes can serve as analogs to study lava flow-related small caves such as surface tubes, inflationary caves, liftup caves, and conduits. In the present work, we have tried to explore the usability of unmanned aerial vehicle (UAV)-derived images for characterizing a solidified lava flow and designing a sequential methodology to identify small caves in the lava flow. In the mapped area of ~0.33 km2, we were able to identify 81 small cave openings, five lava flow morphologies, and five small cave types using 2 cm/pixel high-resolution images. The results display the usefulness of UAV imaging for such analogous research, and also highlight the possibility of the widespread presence of similar small cave openings in Martian lava fields. Such small openings can facilitate optimal air circulation within the caves while sheltering the insides from physical weathering and harmful radiations. Using the available best resolution remote sensing images, we extend the analogy through the contextual and geomorphological analysis of several possible pit craters in the Tharsis region of Mars, in a region of extremely vesicular and fragile lava crust with pahoehoe-type morphology. We report two possible pit craters in this region, with diameters as small as ~20 m. The possibility that such small cave openings can lead to vast subterranean hollow spaces on Mars cannot be ruled out considering its low gravity.
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| 48. |
- Schwenzer, Susanne P., et al.
(författare)
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Fluids during diagenesis and sulfate vein formation in sediments at Gale crater, Mars
- 2016
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Ingår i: Meteoritics and Planetary Science. - : Wiley. - 1086-9379 .- 1945-5100. ; 51:11, s. 2175-2202
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Tidskriftsartikel (refereegranskat)abstract
- We model the fluids involved in the alteration processes recorded in the Sheepbed Member mudstones of Yellowknife Bay (YKB), Gale crater, Mars, as revealed by the Mars Science Laboratory Curiosity rover investigations. We compare the Gale crater waters with fluids modeled for shergottites, nakhlites, and the ancient meteorite ALH 84001, as well as rocks analyzed by the Mars Exploration rovers, and with terrestrial ground and surface waters. The aqueous solution present during sediment alteration associated with phyllosilicate formation at Gale was high in Na, K, and Si; had low Mg, Fe, and Al concentrations—relative to terrestrial groundwaters such as the Deccan Traps and other modeled Mars fluids; and had near neutral to alkaline pH. Ca and S species were present in the 10−3 to 10−2 concentration range. A fluid local to Gale crater strata produced the alteration products observed by Curiosity and subsequent evaporation of this groundwater-type fluid formed impure sulfate- and silica-rich deposits—veins or horizons. In a second, separate stage of alteration, partial dissolution of this sulfate-rich layer in Yellowknife Bay, or beyond, led to the pure sulfate veins observed in YKB. This scenario is analogous to similar processes identified at a terrestrial site in Triassic sediments with gypsum veins of the Mercia Mudstone Group in Watchet Bay, UK.
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| 49. |
- Shekhar, Mayank, et al.
(författare)
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Himalayan glaciers experienced significant mass loss during later phases of little ice age
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- To date, there is a gap in the data about the state and mass balance of glaciers in the climate-sensitive subtropical regions during the Little Ice Age (LIA). Here, based on an unprecedented tree-ring sampling coverage, we present the longest reconstructed mass balance record for the Western Himalayan glaciers, dating to 1615. Our results confirm that the later phase of LIA was substantially briefer and weaker in the Himalaya than in the Arctic and subarctic regions. Furthermore, analysis of the time-series of the mass-balance against other time-series shows clear evidence of the existence of (i) a significant glacial decay and a significantly weaker magnitude of glaciation during the latter half of the LIA; (ii) a weak regional mass balance dependence on either the El Niño-Southern Oscillation (ENSO) or the Total Solar Irradiance (TSI) taken in isolation, but a considerable combined influence of both of them during the LIA; and (iii) in addition to anthropogenic climate change, the strong effect from the increased yearly concurrence of extremely high TSI with El Niño over the past five decades, resulting in severe glacial mass loss. The generated mass balance time-series can serve as a source of reliable reconstructed data to the scientific community.
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| 50. |
- Singh, Shaktiman, et al.
(författare)
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Quantifying the Congruence between Air and Land Surface Temperatures for Various Climatic and Elevation Zones of Western Himalaya
- 2019
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Ingår i: Remote Sensing. - : MDPI. - 2072-4292. ; 11:24
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Tidskriftsartikel (refereegranskat)abstract
- The surface and near-surface air temperature observations are primary data for glacio-hydro-climatological studies. The in situ air temperature (Ta) observations require intense logistic and financial investments, making it sparse and fragmented particularly in remote and extreme environments. The temperatures in Himalaya are controlled by a complex system driven by topography, seasons, and cryosphere which further makes it difficult to record or predict its spatial heterogeneity. In this regard, finding a way to fill the observational spatiotemporal gaps in data becomes more crucial. Here, we show the comparison of Ta recorded at 11 high altitude stations in Western Himalaya with their respective land surface temperatures (Ts) recorded by Moderate Resolution Imagining Spectroradiometer (MODIS) Aqua and Terra satellites in cloud-free conditions. We found remarkable seasonal and spatial trends in the Ta vs. Ts relationship: (i) Ts are strongly correlated with Ta (R2 = 0.77, root mean square difference (RMSD) = 5.9 °C, n = 11,101 at daily scale and R2 = 0.80, RMSD = 5.7 °C, n = 3552 at 8-day scale); (ii) in general, the RMSD is lower for the winter months in comparison to summer months for all the stations, (iii) the RMSD is directly proportional to the elevations; (iv) the RMSD is inversely proportional to the annual precipitation. Our results demonstrate the statistically strong and previously unreported Ta vs. Ts relationship and spatial and seasonal variations in its intensity at daily resolution for the Western Himalaya. We anticipate that our results will provide the scientists in Himalaya or similar data-deficient extreme environments with an option to use freely available remotely observed Ts products in their models to fill-up the spatiotemporal data gaps related to in situ monitoring at daily resolution. Substituting Ta by Ts as input in various geophysical models can even improve the model accuracy as using spatially continuous satellite derived Ts in place of discrete in situ Ta extrapolated to different elevations using a constant lapse rate can provide more realistic estimates.
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