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- Bhardwaj, Anshuman, et al.
(author)
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UAV Imaging of a Martian Brine Analogue Environment in a Fluvio-Aeolian Setting
- 2019
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In: Remote Sensing. - : MDPI. - 2072-4292. ; 11:18
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Journal article (peer-reviewed)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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| 2. |
- Martin-Torres, Javier, et al.
(author)
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The HABIT (HabitAbility: Brine Irradiation and Temperature) environmental instrument for the ExoMars 2022 Surface Platform
- 2020
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In: Planetary and Space Science. - : Elsevier. - 0032-0633 .- 1873-5088. ; 190
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Journal article (peer-reviewed)abstract
- The HABIT (HabitAbility: Brine Irradiation and Temperature) instrument is a European payload of the ExoMars 2022 Surface Platform Kazachok that will characterize the present-day habitability at its landing place in Oxia Planum, Mars. HABIT consists of two modules: (i) EnvPack (Environmental Package) that monitors the thermal environment (air and ground), the incident ultraviolet radiation, the near surface winds and the atmospheric dust cycle; and (ii) BOTTLE (Brine Observation Transition To Liquid Experiment), an In-situ Resource Utilization instrument to produce liquid water for future Mars exploration. BOTTLE will be used also to investigate the electrical conductivity properties of the martian atmosphere, the present-day atmospheric-ground water cycle and to evaluate if liquid water can exist on Mars in the form of brines, and for how long. These variables measured by HABIT are critical to determine the present and future habitability of the martian surface. In this paper, we describe in detail the HABIT instrument and sensors, together with the calibration of its Flight Model (FM) and the Engineering Qualification Model (EQM) versions. The EnvPack module has heritage from previous missions operating on the surface of Mars, and the environmental observations of its sensors will be directly comparable to those delivered by those missions. HABIT can provide information of the local temperature with ±0.2 °C accuracy, local winds with ±0.3 m/s, surface brightness temperature with ±0.8 °C, incident UV irradiance with 10% error of its absolute value in the UV-A, UV-B, UV-C ranges, as well as in the total UV-ABC range, and two additional wavebands, dedicated to ozone absorption. The UV observations can be used to derive the total opacity column and thus monitor the dust and ozone cycles. BOTTLE can demonstrate the hydration state of a set of four deliquescent salts, which have been found on Mars (calcium chloride, ferric sulphate, magnesium perchlorate and sodium perchlorate) by monitoring their electric conductivity (EC). The EC of the air and the dry salts under Earth ambient, clean room conditions is of the order of 0.1 μScm−1. We have simulated HABIT operations, within an environmental chamber, under martian conditions similar to those expected at Oxia Planum. For dry, CO2 atmospheric conditions at martian pressures, the air EC can be as low as 10−8 μScm−1, however it increases with the relative humidity (RH) percentage. The laboratory experiments show that after an increase from 0 to 60% RH within a few hours, the EC of the air increased up to 10−1 μScm−1, magnesium perchlorate hydrated and reached values of 10 μScm-1, whereas calcium chloride deliquesced forming a liquid state with EC of 102 μScm−1. HABIT will operate with a regular cadence, through day and night. The Electronic Unit (EU) is protected with a heater that is activated when its temperature is below −33 °C and disabled if the temperature of the surface platform rises above −30 °C. Additionally, the heaters of the BOTTLE unit can be activated to dehydrate the salts and reset the experiment. HABIT weighs only 918 g. Its power consumption depends on the operation mode and internal temperature, and it varies between 0.7 W, for nominal operation, and 13.1 W (when heaters are turned on at full intensity). HABIT has a baseline data rate of 1.5 MB/sol. In addition to providing critical environmental observations, this light and robust instrument, will be the first demonstrator of a water capturing system on the surface of Mars, and the first European In-Situ Resource Utilization in the surface of another planet.
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| 3. |
- Sam, Lydia, et al.
(author)
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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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In: Remote Sensing. - : MDPI. - 2072-4292. ; 12:12
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Journal article (peer-reviewed)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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