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Download (.pdf) Chlorate salts and solutions on Mars
published in Geophysical Research Letters, April 2012
Chlorate (ClO3−) is an intermediate oxidation species between chloride (Cl−) and perchlorate (ClO4−), both of which... more Chlorate (ClO3−) is an intermediate oxidation species between chloride (Cl−) and perchlorate (ClO4−), both of which were found at the Phoenix landing site by the Wet Chemistry Lab (WCL). The chlorate ion is almost as stable as perchlorate, and appears to be associated with perchlorate in most terrestrial reservoirs (e.g. Atacama and Antarctica). It is possible that chlorate contributed to the ion sensor response on the WCL, yet was masked by the strong perchlorate signal. However, very little is known about chlorate salts and their effect on the stability of water. We performed evaporation rate experiments in our Mars simulation chamber, which enabled us to determine the activity of water for various concentrations. From this we constructed solubility diagrams for NaClO3, KClO3, Mg(ClO3)2 and Ca(ClO3)2, and determined the Pitzer parameters for each salt. Chlorate salt eutectic temperatures range from 270 K (KClO3) to 204 K (Mg(ClO3)2). Modeling the addition of chlorate to the initial WCL solutions shows that it precipitates in concentrations comparable to other common salts, such as gypsum and epsomite, and implies that chlorates may play an important role in the wet chemistry on Mars.
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Seen by: PRELIMINARY STUDY OF THE PHYSIOLOGICAL DEMANDS OF MARS ANALOGUE EXTRAVEHICULAR ACTIVITY
Ever since humans began having a presence in space it has been observed that exposure to the micro-gravity environment... more
Ever since humans began having a presence in space it has been observed that exposure to the micro-gravity environment initiates a series of adaptations of physiological systems. These adaptations constitute deleterious and potentially hazardous conditions during microgravity habitation and especially on return to planetary gravitational fields. These adaptations include: muscle atrophy, cardiovascular deconditioning, orthostatic intolerance, and bone demineralization. In order to counteract these deconditioning effects several countermeasures have been proposed, the most practiced one
being physical exercise. The purpose of this study was to investigate the physiological demands of simulated Mars exploration as a first step in determining the physical fitness requirements of interplanetary explorers. The study took place during a Mars Society Canada geological training mission to the Mars Desert Research Station (MDRS) in Utah, USA. Six crew members were outfitted with a CosMed portable gas exchange analyzer to determine metabolic cost during two hill runs to exhaustion and during at least two extra-vehicular activities (EVAs) while donning an analogue Mars suit. The EVAs were planned to simulate geological surveying of the Martian surface. The average VO2 peak during a hill run was 52.4 ± 1.0
ml/kg/min. The peak VO2 reached during a given EVA was 35.9 ± 0.9ml/kg/min. There was a correlation between aerobic fitness and distance covered during an EVA (R2=0.34) resulting in a greater demand for oxygen in a given time period for more fit crew members (R2=0.86). Therefore, we recommend that future simulations use distance covered rather than time elapsed as the criteria for termination
of EVA in order to better represent life support constraints.
Furthermore, this investigation shows that physiological testing is possible within the framework of current Mars analogue missions, and that further study would be useful in determining both the physical fitness requirements of Marsnauts as well as life support decisions for mission planners. It is hoped that a full scale study of this type will be
included in future science focusedEver since humans began having a presence in space it has been observed that exposure to the micro-gravity environment initiates a series of adaptations of physiological systems. These adaptations
constitute deleterious and potentially hazardous conditions during microgravity habitation and especially on return to planetary gravitational fields. These adaptations include: muscle atrophy, cardiovascular deconditioning, orthostatic intolerance, and bone demineralization. In order to counteract these deconditioning effects several countermeasures have been proposed, the most practiced one being physical exercise. The purpose of this study was to investigate the physiological demands of simulated Mars exploration as a first step
in determining the physical fitness requirements of interplanetary explorers. The study took place during a Mars Society Canada geological training mission to the Mars Desert Research Station (MDRS) in Utah, USA. Six crew members were outfitted with a CosMed portable gas exchange analyzer to determine metabolic cost during two hill runs to exhaustion and during at least two extra-vehicular activities (EVAs) while donning an analogue Mars suit. The EVAs were planned to simulate geological surveying of the Martian surface. The average VO2 peak during a hill run was 52.4 ± 1.0 ml/kg/min. The peak VO2 reached during a given EVA was 35.9 ± 0.9 ml/kg/min. There was a correlation between aerobic fitness and distance covered during an EVA (R2=0.34) resulting in a greater demand for oxygen in a given time period for more fit crew members (R2=0.86). Therefore, we recommend that future simulations use distance covered rather than time elapsed as the criteria for termination of EVA in order to better represent life support constraints. Furthermore, this investigation shows that physiological testing is possible within the framework of current Mars analogue missions, and
that further study would be useful in determining both the physical fitness requirements of Marsnauts as well as life support decisions for mission planners. It is hoped that a full scale study of this type will be included in future science focused Mars analogue expeditions.
Seasonally active slipface avalanches in the north polar sand sea of Mars: Evidence for a wind-related origin
Co-authored with Jim Bell.
Geophysical Research Letters, 39, L09201, doi:10.1029/2012GL051329
Meter-scale MRO/HiRISE camera images of dune slipfaces in the north polar sand sea of Mars reveal the presence of deep... more Meter-scale MRO/HiRISE camera images of dune slipfaces in the north polar sand sea of Mars reveal the presence of deep alcoves above depositional fans. These features are apparently active under current climatic conditions, because they form between observations taken in subsequent Mars years. Recently, other workers have hypothesized that the alcoves form due to destabilization and mass-wasting during sublimation of CO2 frost in the spring. While there is evidence for springtime modification of these features, our analysis of early springtime images reveals that over 80% of the new alcoves are visible underneath the CO2 frost. Thus, we present an alternative hypothesis that formation of new alcoves and fans occurs prior to CO2 deposition. We propose that fans and alcoves form primarily by aeolian processes in the mid- to late summer, through a sequence of aeolian deposition on the slipface, over-steepening, failure, and dry granular flow. An aeolian origin is supported by the orientations of the alcoves, which are consistent with recent wind directions. Furthermore, morphologically similar but much smaller alcoves form on terrestrial dune slipfaces, and the size differences between the terrestrial and martian features may reflect cohesion in the near-subsurface of the martian features. The size and preservation of the largest alcoves on the martian slipfaces also support the presence of an indurated surface layer; thus, new alcoves might be sites of early spring CO2 sublimation and secondary mass-wasting because they act as a window to looser, less indurated materials that warm up more quickly in the spring.
Widespread weathered glass on the surface of Mars
Briony Horgan and Jim Bell, published in Geology, May 2010
Low albedo sediments cover >107 km2 in the northern lowlands of Mars, but the composition and origin of these... more Low albedo sediments cover >107 km2 in the northern lowlands of Mars, but the composition and origin of these widespread deposits have remained ambiguous despite many previous investigations. Here we use near-infrared spectra acquired by the Mars Express OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité) imaging spectrometer to show that these sediments exhibit spectral characteristics that are consistent with both high abundances of iron-bearing glass and silica-enriched leached rinds on glass. This interpretation is supported by observations of low-albedo soil grains with possible rinds at the Phoenix Mars Lander landing site in the northern lowlands. By comparison with the extensive glass-rich dune fields and sand sheets of Iceland, we propose an explosive volcanic origin for these glass-rich sediments. We also propose that the glassy remnant rinds on the sediments are the result of postdepositional alteration, as these rinds are commonly formed in arid terrestrial volcanic environments during water-limited, moderately acidic leaching. These weathered, glass-rich deposits in the northern lowlands are also colocated with the strongest concentrations of a major global compositional surface type previously identified in mid-infrared spectra, suggesting that they may be representative of global processes. Our results provide potential confirmation of models suggesting that explosive volcanism has been widespread on Mars, and also raise the possibilities that glass-rich volcaniclastics are a major source of eolian sand on Mars and that widespread surficial aqueous alteration has occurred under Amazonian climatic conditions.
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Penser la colonie humaine sur Mars comme une question sociale
Un jour, peut-être, des hommes se rendront sur Mars et s’y établiront. La distance rendra les voyages et la... more Un jour, peut-être, des hommes se rendront sur Mars et s’y établiront. La distance rendra les voyages et la communication rares. Si bien qu’un jour l’humanité se scindera en deux. Comment appréhendera-t-on cette altérité radicale?
Sampling methane in hydrothermal minerals on Earth and Mars
by Sean McMahon
Sean McMahon
John Parnell
Nigel J. F. Blamey
The source of Martian atmospheric methane is unknown. On Earth, hydrothermal mineral deposits contain ancient methane... more The source of Martian atmospheric methane is unknown. On Earth, hydrothermal mineral deposits contain ancient methane together with a host of chemical and geological lines of evidence for the mechanism of gas production. Such deposits are therefore potentially attractive sampling sites on Mars. In order to evaluate this potential, hydrothermal calcite veins were sampled across the Caithness region of Scotland and analysed for methane by an incremental-crushing mass spectrometry technique that may be adaptable to Mars rovers. Methane was detected in all samples. Variations in the quantity of methane released were found to relate directly to the geological history of the localities. Calcite particle size was found to affect measurements in a systematic and informative way. Oxidative weathering had no discernable effect on methane recoverability. These results suggest that the technique is sensitive and informative enough to deserve consideration for missions to Mars.
Distribution of hydrated minerals in the north polar region of Mars
Journal of Geophysical Research - Planets, 2009
The previous discovery of extensive deposits of hydrated minerals in Olympia Planum in the north polar region of Mars... more The previous discovery of extensive deposits of hydrated minerals in Olympia Planum in the north polar region of Mars by the Mars Express OMEGA instrument raises important questions about the origin and subsequent redistribution of these hydrated minerals. Here we present a new map of the distribution of hydrated minerals within the north polar region of Mars by applying both standard and new spectral analysis techniques to near-infrared spectral data from OMEGA. Our results are in agreement with the previous OMEGA observations but also show more extensive detections of hydrated minerals throughout the circumpolar plains, as well as new detections of hydrated minerals on the surface of Planum Boreum and within the polar troughs. We find that while the circumpolar plains hydration signatures appear to be correlated with the dark dunes of the north polar erg, hydration signatures in Planum Boreum instead appear to be correlated with the north polar veneers and their sources within the polar layered deposits. By applying laboratory-derived empirical models of the dependence of gypsum spectra on grain size and abundance, we provide approximate abundance estimates for the hydrated minerals we have identified in Observatoire pour la Mine´ ralogie, l’Eau, les Glaces et l’Activite´ (OMEGA) and Compact Reconnaissance Imaging Spectrometer (CRISM) data. We find that the presence of hydrated minerals throughout the north polar region suggests (1) a complex cycle of sediment exchange between the Olympia Planum dunes and the other polar units; (2) an earlier origin for the hydrated minerals than originally postulated; and (3) the occurrence of significant water activity in this region during the Amazonian.
Ice and sulfate induration in the martian north polar sand sea
Presented at the 2nd Planetary Dunes Workshop, 05/2010
Saltation has been a major erosional and depositional force on the surface of Mars, but the dynamics and timescales... more Saltation has been a major erosional and depositional force on the surface of Mars, but the dynamics and timescales that govern the movement of martian sand dunes are poorly understood. In particular, major insights are needed into the mechanisms that cause induration of sand dunes and how these mechanisms affect dune migration rates. Possible modes of induration include chemical (cementation by salts, ferricrete, etc.), physical (settling and compaction of sand and/or dust), and niveo-aeolian (cementation by pore or interbedded ice). This study aims to search for evdience of each of these processes and evaluate their relative influence by examining dunes within the north polar sand sea, which encircles and is sourced from within the north polar plateau (Planum Boreum) [4]. The north polar sand sea offers a unique opportunity to study all of the above processes in one location, as both ice and soluble sulfates are present in the dune fields.
Searching for Pedogenic Phyllosilicates in Ancient Soils on Mars
Presented at the 2011 AGU Fall Meeting
On Earth, vast deposits rich in phyllosilicates are commonly created during soil formation, or pedogenesis. When soils... more
On Earth, vast deposits rich in phyllosilicates are commonly created during soil formation, or pedogenesis. When soils are preserved in the stratigraphic record as paleosols, they become valuable resources for terrestrial geologists because paleosol isotopes, mineralogy, and chemical weathering profiles can be used to reconstruct ancient surface environments and to provide quantitative constraints on regional paleo-climate. Thus, paleosol sequences developed in sedimentary settings can record millions of years of surface and climatic evolution. Ancient paleosols on Earth also have excellent organic and biosignature preservation potential, and therefore harbor some of the oldest known (2-3 Ga) non-marine organics, biosignatures, and fossils.
On Mars, pedogenesis in the ancient past may be responsible for some of the phyllosilicate-bearing units observed today, especially for regionally extensive deposits and those in clear sedimentary settings (e.g., Arabia Terra/Mawrth Vallis, Gale Crater, Noctis Labyrinthus). Many of these possibly pedogenic deposits exhibit compositional layering (e.g., interbedded kaolinites, smectites, and sulfates), which may have formed due to episodic sediment deposition under changing environmental conditions. Such deposits represent excellent targets for in situ investigation, as finding and characterizing paleosols on Mars would allow us to place constraints on the extent and duration of past surface and near-surface habitability, and may even provide preserved samples of ancient martian organics.
We are currently investigating a broad range of methods for identifying and characterizing paleosols on Mars from orbit and in situ with Mars Science Laboratory, based on analysis of phyllosilicate-rich (30-95 wt.%) Eocene-Oligocene paleosols in the Painted Hills of the John Day Fossil Beds National Monument in Eastern Oregon. These paleosols were formed under a wide range of environmental conditions, and include highly weathered soils rich in well-crystalline oxides and kaolinites, moderately weathered soils rich in smectites, and minimally weathered soils rich in poorly-crystalline allophanes and ferrihydrite.
Here we present (1) an overview of the climatic regimes that lead to the pedogenesis of specific phyllosilicate minerals, (2) the near and mid-infrared spectral properties and interpreted mineral assemblages of these terrestrial paleosols, and (3) an evaluation of a pedogenic origin for phyllosilicates at several sites on Mars, including those listed above. Preliminary results from near-infrared spectral analysis of our terrestrial paleosols indicate that paleo-environment can be constrained based on mineral assemblages interpreted from spectral properties, including phyllosilicate composition (constrains water availability), the presence of allophane and ferrihydrite (indicating a cool climate), and the strength of oxide absorptions (constrains soil maturity). Mineral assemblages can also be used to detect burial diagenesis by the presence of diagenetic minerals, including celadonite, illite, and hematite (in the presence of phyllosilicates indicating less mature soils). Our results also indicate that poorly crystalline minerals (allophane and ferrihydrite) can be spectrally dominant in these soils even after burial and diagenesis.
An Interdisciplinary Approach to Human-Robotic Cooperation in Mars Exploration
Dag Evensberget, Christopher Brunskill, Christopher Johnson, Mark McCrum, Jeffrey R. Osborne, Bernd Michael Weiss, Katarina Eriksson, Reinhold Ewald
Proc. of the 62nd International Astronautical Congress, Cape Town, South Africa, 2011An Interdisciplinary Approach to Human-Robotic Cooperation in Mars Exploration
The recent past has seen robots develop into autonomous artificial agents capable of executing complex tasks. In the... more The recent past has seen robots develop into autonomous artificial agents capable of executing complex tasks. In the near future, robots will likely develop the ability to adapt and learn from their surroundings. Robots have reliance, accuracy, and can operate in hostile environments - all attributes well suited for space exploration. Robots also reduce mission costs, increase design flexibility, and maximize data production. On the other hand, when faced with new scenarios and unexpected events, robots pale in comparison with intuitive and creative human counterparts. The future of space exploration will have to intelligently balance the flexibility and ingenuity of humans with robust and sophisticated robotic systems. The Cooperation of Humans And Robots for Mars (CHARM) team at the 2011 Space Studies Program of the International Space University integrates international, intercultural, and interdisciplinary perspectives to investigate Mars exploration objectives, robotic capabilities, and the interaction between humans and robots. Based on the goals of various space agencies, this report selects an exploration objective for the time frame between 2015 and 2035, and drafts different scenarios to accomplish this objective. Each scenario uses different degrees of human-robot interaction. A theoretical model is then developed based on discrete requirements to help create an effective combination of human and robots. The CHARM model uses an interdisciplinary approach, including technical, societal, political, legal, financial, scientific and mission risk perspectives. The results of the CHARM model are then further analyzed using these interdisciplinary aspects, with considerations to the future studies of human-robot cooperation. The CHARM team believes that this decision-making model can be used to select missions more efficiently and rationally, thus bringing down both mission costs and risks, and making space exploration more feasible.
Soil simulant sourcing for the ExoMars rover testbed
Thibault P. Gouache, Nildeep Patel, Christopher Brunskill, Gregory P. Scott, Chakravarthini M. Saaj, Marcus Matthews and Liang Cui
Journal of Planetary and Space Science
ExoMars is the European Space Agency (ESA) mission to Mars planned for launch in 2018, focusing on exobiology with the... more ExoMars is the European Space Agency (ESA) mission to Mars planned for launch in 2018, focusing on exobiology with the primary objective of searching for any traces of extant or extinct carbon-based micro-organisms. The on-surface mission is performed by a near-autonomous mobile robotic vehicle (also referred to as the rover) with a mission design life of 180 sols (Patel et al., 2010). In order to obtain useful data on the tractive performance of the ExoMars rover before flight, it is necessary to perform mobility tests on representative soil simulant materials producing a Martian terrain analogue under terrestrial laboratory conditions. Three individual types of regolith shown to be found extensively on the Martian surface were identified for replication using commercially available terrestrial materials, sourced from UK sites in order to ensure easy supply and reduce lead times for delivery. These materials (also referred to as the Engineering Soil (ES-x) simulants) are: a fine dust analogue (ES-1); a fine aeolian sand analogue (ES-2); and a coarse sand analogue (ES-3). Following a detailed analysis, three fine sand regolith types were identified from commercially available products. Each material was used in its off-the-shelf state, except for ES-2, where further processing methods were used to reduce the particle size range. These materials were tested to determine their physical characteristics, including the particle size distribution, particle density, particle shape (including angularity/sphericity) and moisture content. The results are analysed to allow comparative analysis with existing soil simulants and the published results regarding in situ analysis of Martian soil on previous NASA (National Aeronautics and Space Administration) missions. The findings have shown that in some cases material properties vary significantly from the specifications provided by material suppliers. This has confirmed the need for laboratory testing to determine the actual parameters to prove that standard geotechnical processes are indeed suitable. The outcomes have allowed the confirmation of each simulant material as suitable for replicating their respective regolith types.
Characterisation of martian soil simulants for the ExoMars rover testbed
Christopher Brunskill, Nildeep Patel, Thibault P. Gouache, Gregory P. Scott, Chakravarthini M. Saaj, Marcus Matthews and Liang Cui
Journal of Terramechanics
The European Space Agency (ESA) ExoMars mission involves landing a rover on the surface of Mars on an exobiology... more The European Space Agency (ESA) ExoMars mission involves landing a rover on the surface of Mars on an exobiology mission to extend the search for life. The locomotion capabilities of the ExoMars rover will enable it to use its scientific instruments in a wide variety of locations. Before it is sent to Mars, this locomotion system must be tested and its performance limitations understood. To test the locomotion performance of the ExoMars rover, three martian regolith simulants were selected: a fine dust analogue, a fine Aeolian sand analogue, and a coarse sand analogue. To predict the performance of the ExoMars rover locomotion system in these three regolith simulants, it is necessary to measure some fundamental macroscopic properties of the materials: cohesion, friction angle, and various bearing capacity constants. This paper presents the tests conducted to determine these properties. During these tests, emphasis was placed on preparing the regolith simulants at different levels of density in order to evaluate its impact on the value of the parameters in particular. It was shown that compaction can influence the Bekker coefficients of pressure-sinkage. The shear properties are consistent with the critical state model at normal stresses similar to those of the ExoMars rover in all but one of the simulants, which showed behaviour more consistent with transitional soil behaviour. It is necessary to give due consideration to these variations to ensure a robust test regime is developed when testing the tractive ability of the ExoMars mobility system.
