Possibility of microscopic liquid water formation at landing sites on Mars and their observational potential

Pál, Bernadett; Keresztúri, A.

doi:10.1016/j.icarus.2016.09.006

Cited by 21 publications

(12 citation statements)

References 33 publications

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“…Gough et al (2016) analysed the formation of liquid water via the deliquescence of calcium chloride at low temperatures and concluded that calcium chloride may help to form liquid water that could cause slope streaks on Mars. Pál and Kereszturi (2016) also predicted the appearance of microscopic amount liquid water on the hygroscopic mineral surfaces on Mars.…”

Section: Water On Earth and Other Terrestrial Planetsmentioning

confidence: 87%

The When and Where of Water in the History of the Universe

Torres¹,

Winter²

2018

Habitability of the Universe Before Earth

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It is undeniable that life as we know it depends on liquid water. It is difficult to imagine any biochemical machinery that does not require water. On Earth, life adapts to the most diverse environments and, once established, it is very resilient. Considering that water is a common compound in the Universe, it seems possible (maybe even likely) that one day we will find life elsewhere in the universe. In this study, we review the main aspects of water as an essential compound for life: when it appeared since the Big Bang, and where it spread throughout the diverse cosmic sites. Then, we describe the strong relation between water and life, as we know it.

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Section: Water On Earth and Other Terrestrial Planetsmentioning

confidence: 87%

The When and Where of Water in the History of the Universe

Torres¹,

Winter²

2018

Habitability of the Universe Before Earth

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“…Several climate models favor a wet but cold surface on early Mars [ 29 ], on which the volumetric and temporal occurrence of liquid water markedly decreased [ 30 ]. Thus, during most of Martian history, only microscopic liquid water (e.g., microscopic liquid brines) may have been present [ 31 , 32 ], though chemical alteration involving perchlorate brines and microscopic liquid films may have been common [ 33 , 34 ]. Importantly, ultraviolet and ionizing radiation can degrade biosignatures at the surface [ 35 ] and subsurface [ 36 ], respectively, and surface oxidizing salts including perchlorate can encourage complete combustion of organic carbon during thermal and evolved gas analysis [ 37 , 38 ], which is currently the only method employed for the detection of organic carbon on Mars.…”

Section: Introductionmentioning

confidence: 99%

Organic Matter Preservation in Ancient Soils of Earth and Mars

Broz

2020

Life

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The emerging field of astropedology is the study of ancient soils on Earth and other planetary bodies. Examination of the complex factors that control the preservation of organic matter and other biosignatures in ancient soils is a high priority for current and future missions to Mars. Though previously defined by biological activity, an updated definition of soil as planetary surfaces altered in place by biological, chemical or physical processes was adopted in 2017 by the Soil Science Society of America in response to mounting evidence of pedogenic-like features on Mars. Ancient (4.1–3.7 billion year old [Byr]) phyllosilicate-rich surface environments on Mars show evidence of sustained subaerial weathering of sediments with liquid water at circumneutral pH, which is a soil-forming process. The accumulation of buried, fossilized soils, or paleosols, has been widely observed on Earth, and recent investigations suggest paleosol-like features may be widespread across the surface of Mars. However, the complex array of preservation and degradation factors controlling the fate of biosignatures in paleosols remains unexplored. This paper identifies the dominant factors contributing to the preservation and degradation of organic carbon in paleosols through the geological record on Earth, and offers suggestions for prioritizing locations for in situ biosignature detection and Mars Sample Return across a diverse array of potential paleosols and paleoenvironments of early Mars. A compilation of previously published data and original research spanning a diverse suite of paleosols from the Pleistocene (1 Myr) to the Archean (3.7 Byr) show that redox state is the predominant control for the organic matter content of paleosols. Most notably, the chemically reduced surface horizons (layers) of Archean (2.3 Byr) paleosols have organic matter concentrations ranging from 0.014–0.25%. However, clay mineralogy, amorphous phase abundance, diagenetic alteration and sulfur content are all significant factors that influence the preservation of organic carbon. The surface layers of paleosols that formed under chemically reducing conditions with high amounts of iron/magnesium smectites and amorphous colloids should be considered high priority locations for biosignature investigation within subaerial paleoenvironments on Mars.

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“…One of the main goals of Mars investigation is “to follow the water” [ 3 ] as a prerequisite for the survival of living entities. Because of low temperatures (e.g., 215 K to 273 K at the equator) [ 3 ] and low Martian atmospheric pressure (600–800 Pa near the surface) [ 1 ], water can exist only as vapor, as ice, in brines [ 4 ], or bounded on the surface of the regolith as interfacial water in a liquid-like state [ 5 ], and it might also form by the process of deliquescence [ 6 ]. The water vapor is of particular interest, because it influences chemical reactions; because of the water content in the lower atmosphere and upper regolith, the phenomena like fog and thin frost layers occur, and could also be important for potential life forms.…”

Section: Introductionmentioning

confidence: 99%

“…A similar investigation in the regular air of the Earth, performed in the same laboratory, has already been described in the literature [ 8 ]. That former paper [ 6 ] is essential for the understanding of the present paper, because the experimental setup, definitions of parameters, and so on, that are used in the present paper, have been explained and defined in the literature [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Humidity Measurement in Carbon Dioxide with Capacitive Humidity Sensors at Low Temperature and Pressure

Lorek

Majewski

2018

Sensors

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In experimental chambers for simulating the atmospheric near-surface conditions of Mars, or in situ measurements on Mars, the measurement of the humidity in carbon dioxide gas at low temperature and under low pressure is needed. For this purpose, polymer-based capacitive humidity sensors are used; however, these sensors are designed for measuring the humidity in the air on the Earth. The manufacturers provide only the generic calibration equation for standard environmental conditions in air, and temperature corrections of humidity signal. Because of the lack of freely available information regarding the behavior of the sensors in CO2, the range of reliable results is limited. For these reasons, capacitive humidity sensors (Sensirion SHT75) were tested at the German Aerospace Center (DLR) in its Martian Simulation Facility (MSF). The sensors were investigated in cells with a continuously humidified carbon dioxide flow, for temperatures between −70 °C and 10 °C, and pressures between 10 hPa and 1000 hPa. For 28 temperature–pressure combinations, the sensor calibration equations were calculated together with temperature–dependent formulas for the coefficients of the equations. The characteristic curves obtained from the tests in CO2 and in air were compared for selected temperature–pressure combinations. The results document a strong cross-sensitivity of the sensors to CO2 and, compared with air, a strong pressure sensitivity as well. The reason could be an interaction of the molecules of CO2 with the adsorption sites on the thin polymeric sensing layer. In these circumstances, an individual calibration for each pressure with respect to temperature is required. The performed experiments have shown that this kind of sensor can be a suitable, lightweight, and relatively inexpensive choice for applications in harsh environments such as on Mars.

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Possibility of microscopic liquid water formation at landing sites on Mars and their observational potential

Cited by 21 publications

References 33 publications

The When and Where of Water in the History of the Universe

The When and Where of Water in the History of the Universe

Organic Matter Preservation in Ancient Soils of Earth and Mars

Humidity Measurement in Carbon Dioxide with Capacitive Humidity Sensors at Low Temperature and Pressure

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