Future Mars Rover Research Articles

Binary phase behavior of select organosulfur compounds in supercritical carbon dioxide: A Monte Carlo molecular simulation study.

Pressure-composition binary phase diagrams were determined for methanethiol, dimethyl sulfide, thiophene, benzothiophene, or dibenzothiophene with carbon dioxide at temperatures from 363 to 453K and pressures from 2 to 20 MPa. Utilizing Gibbs ensemble Monte Carlo molecular simulation, phase coexistence compositions were determined, along with the impact of 4% water cosolvent on select results. Solution structure as a function of pressure and temperature is characterized via radial distribution functions. Comparison to available experimental composition data gives overall mean absolute percentage deviations of 2.2% for thiophene, 37% for methanethiol, and 99% for benzothiophene. Solubilities in a CO2-rich phase are calculated to be sufficient to allow extraction and detection of the compounds studied here via supercritical fluid chromatography and mass spectrometry as a possible analysis approach for future Mars rover missions.

Rover-mounted Hydrated Mineral Detector for Mars Exploration: A Preliminary Report

The rover-mounted hydrated mineral detector (HMD) is based on a dielectric spectrometer (tuned frequency range of 0.8–4 MHz) that will detect bulk subsurface hydrated minerals in local scale. The HMD is a compact, low-mass (1.5 kg), and low-power instrument (5 W) suitable for Mars application. Compared with orbiter-based instruments with low horizontal resolution (5–10 km), the HMD will offer high resolution (2 m) that can identify optimal sampling sites for the presence of hydrated minerals. From field testing with reduced radio frequency (RF) power (P rf = 10 mW), the HMD demonstrated detection of shallow buried gypsum samples. When developed with full RF power, the HMD could potentially detect hydrates down to depths of 2 m (P rf = 1 W) or 4 m (P rf = 36 W) in Martian soil. Unlike conventional dielectric spectrometers, which require small amounts of the sample (5–10 g) to be placed inside sample cells, the HMD will detect hydrated minerals by scanning over the Mars surface mounted on a rover platform (<1 m above ground) without any sample preparation. This capability will allow future rovers to rapidly assess the scientific potential of field sites. Compared with optical techniques that are limited to surface exposed mineralogical features that could be obscured by dust and weathering products, the HMD will detect bulk subsurface hydrated minerals along the rover traverse irrespective of surface obscuration. The HMD (TRL 4) is a proof-of-concept instrument that can be developed and matured for future Mars rover missions.

Ester and Carbonate-Based Low Temperature Electrolytes in High Specific Energy and High Power 18650 Li-Ion Cells for Future NASA Missions

NASA continues to have an interest in developing high specific energy and high power rechargeable batteries that can operate well over a wide temperature range. Concepts for applications that could be enabled or enhanced by such technology include: (i) future Mars landers, (ii) future Mars rovers, including a possible Mars Sample Return mission, and (iii) future planetary aerial vehicles, where high specific energy, high power and wide operating temperature range is desired. Future missions to some of the distant icy moons of Jupiter and Saturn are also anticipated to benefit from improved ultra-low temperature rechargeable batteries with high specific energy.1 To meet these needs, the Electrochemical Technologies Group (ETG) at the Jet Propulsion Laboratory (JPL) has developed a number of low temperature Li-ion electrolytes utilizing various approaches. In general, the performance targets of this work is to provide operation over the temperature range of +40oC to -60oC (delivering up to 150 Wh/kg at -40oC at reasonable rates). In addition, continuous operation at low temperatures is desired, so the cells should possess good charge characteristics without undesirable lithium plating.In previous collaborative work with E-One Moli Energy Ltd.1, we have demonstrated excellent specific energy at -40oC (> 150 Wh/kg) at low rates (C/100) in custom 18650-sized Li-ion cells containing JPL-developed electrolytes. The electrolytes investigated included all-carbonate-based low EC-content electrolyte formulations, as well as solutions containing ester co-solvents with various additives.2-6 In an extension of this work, we have investigated the performance of a number of Li-ion electrolytes optimized for low temperature performance in custom high specific energy cells as well high power prototype 18650-size cells manufactured by E-One Moli. The electrolytes evaluated included blends which contain elements of various approaches, including (i) ester co-solvents (such as methyl propionate, methyl butyrate, and propyl butyrate), (ii) the use of electrolyte additives (such as VC and FEC), and (ii) the use of mixed lithium electrolyte salts. In contrast to the previous work that was focused on low rate operation at high temperature, emphasis was placed on characterizing the cells using more aggressive discharge rates over a range of temperatures.To evaluate the high specific energy and high power 18650-size cells, extensive discharge rate characterization was performed over a wide temperature range (down to -80oC). Emphasis was also devoted to establishing the charge acceptance characteristics of the cells at very low temperatures, especially at -40oC. Given that lithium plating when charging at low temperatures is a known degradation mode of Li-ion cells in general, attention was focused upon characterizing the conditions in which its likelihood may be more pronounced and attempting to detect its occurrence indirectly. These results will be compared to baseline commercial off the shelf (COTS) cells. DC current interrupt impedance measurements have also been performed as a function of temperature in an attempt to more fully understand the impact of electrolyte type upon the low temperature performance for the cells.ACKNOWLEDGEMENTThe work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) and supported by an internal JPL Research and Technology Development (R&TD) Fund. The information in this document is pre-decisional and is provided for planning and discussion only.

Ester and Carbonate-Based Low Temperature Electrolytes in High Specific Energy and High Power 18650 Li-Ion Cells for Future NASA Missions

NASA continues to have an interest in developing high specific energy and high power rechargeable batteries that can operate well over a wide temperature range. Concepts for applications that could be enabled or enhanced by such technology include: (i) future Mars landers, (ii) future Mars rovers, including a possible Mars Sample Return mission, and (iii) future planetary aerial vehicles, where high specific energy, high power and wide operating temperature range is desired. Future missions to some of the distant icy moons of Jupiter and Saturn are also anticipated to benefit from improved ultra-low temperature rechargeable batteries with high specific energy.1 To meet these needs, the Electrochemical Technologies Group (ETG) at the Jet Propulsion Laboratory (JPL) has developed a number of low temperature Li-ion electrolytes utilizing various approaches. In general, the performance targets of this work is to provide operation over the temperature range of +40oC to -60oC (delivering up to 150 Wh/kg at -40oC at reasonable rates). In addition, continuous operation at low temperatures is desired, so the cells should possess good charge characteristics without undesirable lithium plating.In previous collaborative work with E-One Moli Energy Ltd.1, we have demonstrated excellent specific energy at -40oC (> 150 Wh/kg) at low rates (C/100) in custom 18650-sized Li-ion cells containing JPL- developed electrolytes. The electrolytes investigated included all-carbonate-based low EC-content electrolyte formulations, as well as solutions containing ester co-solvents with various additives. 2-6 In an extention of this work, we have investigated the performance of a number of Li-ion electrolytes optimized for low temperature performance in custom high specific energy cells as well high power prototype 18650-size cells manufactured by E-One Moli. The electrolytes evaluated included blends which contain elements of various approaches, including (i) ester co-solvents (such as methyl propionate, methyl butyrate, and propyl butyrate), (ii) the use of electrolyte additives (such as VC and FEC), and (ii) the use of mixed lithium electrolyte salts. In contrast to the previous work that was focused on low rate operation at high temperature, emphasis was placed on characterizing the cells using more aggressive discharge rates over a range of temperatures.To evaluate the high specific energy and high power 18650-size cells, extensive discharge rate characterization was performed over a wide temperature range (down to -80oC). Emphasis was also devoted to establishing the charge acceptance characteristics of the cells at very low temperatures, especially at -40oC. Given that lithium plating when charging at low temperatures is a known degradation mode of Li-ion cells in general, attention was focused upon characterizing the conditions in which its likelihood may be more pronounced and attempting to detect its occurrence indirectly. These results will be compared to baseline commercial off the shelf (COTS) cells. DC current interrupt impedance measurements have also been performed as a function of temperature in an attempt to more fully understand the impact of electrolyte type upon the low temperature performance for the cells. ACKNOWLEDGEMENT The work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) and supported by an internal JPL Research and Technology Development (R&TD) Fund. The information in this document is pre-decisional and is provided for planning and discussion only. 1. M. C. Smart, F. C. Krause, J. –P. Jones, L. D. Whitcanack, , B. V. Ratnakumar, E. J. Brandon, and M. Shoesmith, 2016 Prime Pacific Rim Meeting on Electrochemical and Solid-State Science, Honolulu, HI, October 2-7, 2016.2. M. C. Smart, B. V. Ratnakumar, K. B. Chin, and L. D. Whitcanack, J. Electrochem. Soc., 157(12), A1361-A1374 (2010).3. M. C. Smart, B. L. Lucht, S. Dalavi, F. C. Krause, and B. V. Ratnakumar, J. Electrochem. Soc., 159 (6), A739-A751 (2012).4. M. C. Smart, B. V. Ratnakumar, F. C. Krause, L. D. Whitcanack, E. A. Dewell, S. F. Dawson, R. B. Shaw, S. Santee, F. J. Puglia, A. Buonanno, C. Deroy, and R. Gitzendanner, NASA Aerospace Battery Workshop, Huntsville, Alabama, November 17-19, 2015.5. M. C. Smart, et. al., 2010 Power Sources Conference, Las Vegas, NV, June 16, 2010, Pages 191-194.6. (a) M. C. Smart, et. al., 214th Meeting of the Electrochemical Society, Honolulu, HI, Oct. 12-17, 2008. (b) M. C. Smart, A. S. Gozdz, L. D. Whitcanack, and B. V. Ratnakumar, 220th Meeting of the Electrochemical Society, Boston, MA, October 11, 2011.

Vision-Based Estimation of Driving Energy for Planetary Rovers Using Deep Learning and Terramechanics

This letter presents a prediction algorithm of driving energy for future Mars rover missions. The majority of future Mars rovers would be solar-powered, which would require energy-optimal driving to maximize the range with limited energy. The essential and arguably the most challenging technology for realizing energy-optimal driving is the capability to predict the driving energy, which is needed to construct an energy-aware cost function for path planning. In this letter, we propose vision-based algorithms to remotely predict the driving energy consumption using machine learning. Specifically, we develop and compare two machine-learning models in this letter, namely VeeGer-EnergyNet and Veeger-TerramechanicsNet, respectively. The former is trained directly using recorded power, while the latter estimates terrain parameters from the images using a simplified-terramechanics model, and calculate the power based on the model. The two approaches are fully automated self-supervised learning algorithms. To combine RGB and depth images efficiently with high accuracy, we propose a new network architecture called Two-PNASNet-5, which is based on PNASNet-5. We collected a new dataset to verify the effectiveness of the proposed approaches. Comparison of the two approaches showed that Veeger-TerramechanicsNet had better performance than VeeGer-EnergyNet.

Discovery of recurring slope lineae candidates in Mawrth Vallis, Mars

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.

Comparison of Suspension Systems and Chassis of Selected Mars Rovers Analogs with a Focus on Introduced Improvement

The article concludes with a thorough evaluation of an usefulness of suspension systems and chassis of Mars Rovers from Bialystok University of Technology and predictions for future Mars rover solutions. A development of technology and ever growing aspirations of mankind resulted in clear progress in the field of Mars exploration rovers. Competitions, involving analogs of Mars rovers, are increasingly more popular among academic societies. The main goal of mentioned initiatives, is to test possible solutions which, over time, may be used in rovers during extraterrestrial missions. The authors focused on a path of a Mars rover analogue development. In the first stage authors analyzed requirements of the University Rover Challenge organized by The Mars Society. Then the article concerns tasks that every modern Mars rover faces during its mission. Next authors considered Mars Rovers analogs designed and built in Faculty of Mechanical Engineering at Bialystok University of Technology. After application’s considerations, authors focused on suspension systems analysis. A major part of the article is a thorough structural analysis of suspension and driving systems of analog Mars rovers build at Faculty of Mechanical Engineering, Bialystok University of Technology [1]. Then there is an comparison of the Curiosity (fig. 1) rover suspension [2] and internal frame with #next Mars Rover.

Supercritical Carbon Dioxide Extraction of Coronene in the Presence of Perchlorate for In Situ Chemical Analysis of Martian Regolith.

The analysis of the organic compounds present in the martian regolith is essential for understanding the history and habitability of Mars, as well as studying the signs of possible extant or extinct life. To date, pyrolysis, the only technique that has been used to extract organic compounds from the martian regolith, has not enabled the detection of unaltered native martian organics. The elevated temperatures required for pyrolysis extraction can cause native martian organics to react with perchlorate salts in the regolith and possibly result in the chlorohydrocarbons that have been detected by in situ instruments. Supercritical carbon dioxide (SCCO2) extraction is an alternative to pyrolysis that may be capable of delivering unaltered native organic species to an in situ detector. In this study, we report the SCCO2 extraction of unaltered coronene, a representative polycyclic aromatic hydrocarbon (PAH), from martian regolith simulants, in the presence of 3 parts per thousand (ppth) sodium perchlorate. PAHs are a class of nonpolar molecules of astrobiological interest and are delivered to the martian surface by meteoritic infall. We also determined that the extraction efficiency of coronene was unaffected by the presence of perchlorate on the regolith simulant, and that no sodium perchlorate was extracted by SCCO2. This indicates that SCCO2 extraction can provide de-salted samples that could be directly delivered to a variety of in situ detectors. SCCO2 was also used to extract trace native fluorescent organic compounds from the martian regolith simulant JSC Mars-1, providing further evidence that SCCO2 extraction may provide an alternative to pyrolysis to enable the delivery of unaltered native organic compounds to an in situ detector on a future Mars rover. Biomarkers-Carbon dioxide-In situ measurement-Mars-Search for Mars' organics. Astrobiology 16, 703-714.

Multi-information fusion based localization algorithm for Mars rover

High-precision autonomous localization technique is essential for future Mars rovers. This paper addresses an innovative integrated localization algorithm using a multiple information fusion approach. Firstly, the output of IMU is employed to construct the two-dimensional (2-D) dynamics equation of Mars rover. Secondly, radio beacon measurement and terrain image matching are considered as external measurements and included into the navigation filter to correct the inertial basis and drift. Then, extended Kalman filtering (EKF) algorithm is designed to estimate the position state of Mars rovers and suppress the measurement noise. Finally, the localization algorithm proposed in this paper is validated by computer simulation with different parameter sets.

Solar zenith angle does not affect Mars ionosphere's electron temperature

Exploration of Mars, whether by spacecraft or by humans in the far‐flung future, requires a deep understanding of Mars's ionosphere—the upper layer of atmosphere where molecules are ionized by the Sun's energy. For example, scientists on Earth trying to communicate with current and future Mars rovers are and will continue to be hindered by free electrons in the ionosphere that can absorb and reflect radio waves. Scientists therefore wonder, What are the various physical properties that can influence the behavior of Mars's ionosphere?

Lipids as universal biomarkers of extraterrestrial life.

In 1965, James Lovelock published a general statement, based on thermodynamic chemical equilibrium principles, about how to detect extant or extinct life on a planet other than Earth. Nearly 50 years later, it is possible to make such measurements with robotic missions such as current and future Mars rovers, and probes to sample icy plumes of Enceladus or Europa. We make a specific recommendation that certain characteristic patterns in the composition of lipid hydrocarbons can only result from a biological process, because the signal arises from a universal requirement related to lipid bilayer fluidity and membrane stability. Furthermore, the pattern can be preserved over millions of years, and instrumentation is already available to be incorporated into flight missions.

Fuzzy-rough feature selection aided support vector machines for Mars image classification

This paper presents a novel application of advanced machine learning techniques for Mars terrain image classification. Fuzzy-rough feature selection (FRFS) is adapted and then employed in conjunction with Support Vector Machines (SVMs) to construct image classifiers. These techniques are integrated to address problems in space engineering where the images are of many classes, large-scale, and diverse representational properties. The use of the adapted FRFS allows the induction of low-dimensionality feature sets from feature patterns of a much higher dimensionality. To evaluate the proposed work, K-Nearest Neighbours (KNNs) and decision trees (DTREEs) based image classifiers as well as information gain rank (IGR) based feature selection are also investigated here, as possible alternatives to the underlying machine learning techniques adopted. The results of systematic comparative studies demonstrate that in general, feature selection improves the performance of classifiers that are intended for use in high dimensional domains. In particular, the proposed approach helps to increase the classification accuracy, while enhancing classification efficiency by requiring considerably less features. This is evident in that the resultant SVM-based classifiers which utilise FRFS-selected features generally outperform KNN and DTREE based classifiers and those which use IGR-returned features. The work is therefore shown to be of great potential for on-board or ground-based image classification in future Mars rover missions.

Facilitating efficient Mars terrain image classification with fuzzy-rough feature selection

This paper presents an application study of exploiting fuzzy-rough feature selection (FRFS) techniques in aid of efficient and accurate Mars terrain image classification. The employment of FRFS allows the induction of low-dimensionality feature sets from sample descriptions of feature vectors of a much higher dimensionality. Supported with comparative studies, the work demonstrates that FRFS helps to enhance both the effectiveness and the efficiency of conventional classification systems such as multi-layer perceptrons and K-nearest neighbors, by minimizing redundant and noisy features. This is of particular significance for on-board image classification in future Mars rover missions.

Surface and subsurface composition of the Life in the Atacama field sites from rover data and orbital image analysis

The Life in the Atacama project examined six different sites in the Atacama Desert (Chile) over 3 years in an attempt to remotely detect the presence of life with a rover. The remote science team, using only orbital and rover data sets, identified areas with a high potential for life as targets for further inspection by the rover. Orbital data in the visible/near infrared (VNIR) and in the thermal infrared (TIR) were used to examine the mineralogy, geomorphology, and chlorophyll potential of the field sites. Field instruments included two spectrometers (VNIR reflectance and TIR emission) and a neutron detector: this project represents the first time a neutron detector has been used as part of a “science‐blind” rover field test. Rover‐based spectroscopy was used to identify the composition of small scale features not visible in the orbital images and to improve interpretations of those data sets. The orbital and ground‐based data sets produced consistent results, suggesting that much of the field sites consist of altered volcanic terrains with later deposits of sulfates, quartz, and iron oxides. At one location (Site A), the ground‐based spectral data revealed considerably greater compositional diversity than was seen from the orbital view. One neutron detector transect provided insight into subsurface hydrogen concentrations, which correlated with life and surface features. The results presented here have implications for targeting strategies, especially for future Mars rover missions looking for potential habitats/paleohabitats.

Patch antennas with switchable slots (PASS) in wireless communications: concepts, designs, and applications

This feature article describes, in a comprehensive and unified fashion, the authors' work on the development of novel kinds of reconfigurable microstrip antennas: patch antennas with switchable slots (PASS). PASS are versatile for wireless communication systems, and their structure is very simple. This article introduces the operational mechanism of PASS, as well as their frequency-ratio control and input impedance tuning. Various PASS designs are presented to demonstrate the capability of PASS in wireless communication. These designs demonstrate the functions of dual-frequency operation, dual-band circular-polarization performance, and circular-polarization diversity with only one layer and a single feed. A practical PASS application for future Mars rover missions is also highlighted: a compact, dual-band, circularly polarized antenna for the UHF band was designed, fabricated, and measured, based on the PASS concept.

Documenting drainage evolution in Bir Kiseiba, southern Egypt: Constraints from ground‐penetrating radar and implications for Mars

Ground‐penetrating radar (GPR) helps to constrain the origin of relict and largely buried fluvial channels in the Bir Kiseiba region of southern Egypt. Our results indicate that the trunk channel to a tributary system identified in Shuttle Imaging Radar data is incised 10–12 m into bedrock, was southwest draining in its final configuration and laterally migrating toward the northwest, and accentuated relief along the nearby Kiseiba escarpment. Alluvium partially filling the main channel likely reflects effects of increasing aridity and bed load combined with less frequent, flashier precipitation. In contrast to defining channel margins, radar data do not indicate subtle stratigraphic changes in bedding related to fluvial aggradation, but do highlight local reflections likely corresponding to relict alluvial bedforms. Our results support the contention that an impulse GPR system, currently under development, could be deployed on a future Mars rover and assist in defining the regional evolution of the landscape and specific targets for sampling.

Die Attachment for −120°C to +20°C Thermal Cycling of Microelectronics for Future Mars Rovers—An Overview1

Active thermal control for electronics on Mars rovers imposes a serious penalty in weight, volume, power consumption, and reliability. Thus, we propose that thermal control be eliminated for future rovers. From a functional standpoint there is no reason that the electronics could not operate over the entire temperature range of the Martian environment, which can vary from a low of ≈−90°C to a high of ≈+20°C during the Martian night and day. The upper end of this range is well within that for conventional electronics. Although the lower end is considerably below that for which conventional—even high-reliability—electronics is designed or tested, it is well established that electronic devices can operate to such low temperatures. The primary concern is reliability of the overall electronic system, especially in regard to the numerous daily temperature cycles that it would experience over the duration of a mission on Mars. Accordingly, key reliability issues have been identified for elimination of thermal control on future Mars rovers. One of these is attachment of semiconductor die onto substrates and into packages. Die attachment is critical since it forms a mechanical, thermal, and electrical interface between the electronic device and the substrate or package. This paper summarizes our initial investigation of existing information related to this issue, in order to form an opinion whether die attachment techniques exist, or could be developed with reasonable effort, to withstand the Mars thermal environment for a mission duration of approximately one earth year. Our conclusion, from a review of literature and personal contacts, is that die attachment can be made sufficiently reliable to satisfy the requirements of future Mars rovers. Moreover, it appears that there are several possible techniques from which to choose and that the requirements could be met by judicious selection from existing methods using hard solders, soft solders, or organic adhesives. Thus, die attachment does not appear to be a roadblock to eliminating thermal control for rover electronics. We recommend that this be further investigated and verified for the specific hardware and thermal conditions appropriate to Mars rovers.