Mars Atmospheric Conditions Research Articles

Flow past triangular airfoil of variable thickness with low Reynolds number in Mars atmosphere

Aerodynamic research on Mars for the past few decades has increased in the development of optimum aerial vehicles for Mars. The current research aims to study the aerodynamics of a triangular airfoil in Mars atmospheric conditions and understand the future regions of flow improvement. A numerical investigation using a Finite Volume Solver has been performed for 0° to 16° angles of attack at low and high flow velocities. Low flow velocities ranging from Re = 3,000 to 7,000 have been considered for the investigation. The nonlinearity in Cl appears as the separation bubble begins to approach the apex on the suction surface. Apart from the separation bubble, a flow recirculation zone is generated for low and high Re. at α = 16°. The highest aerodynamic performance is at α = 6°.

Airfoil optimization methodology and CFD validation for Mars atmospheric conditions

Airfoil optimization methodology and CFD validation for Mars atmospheric conditions

Metals extraction on Mars through carbothermic reduction

In situ resource utilization (ISRU), and specifically the extraction and production of structural metals from Martian soil, is important for supporting further exploration, habitat and industrial developments on Mars. Considering Mars's atmospheric conditions and soil compositions, systematic analyses (supported by thermodynamic calculations) on possible metal extraction processes have been carried out. The analyses suggest that carbothermic reduction of Martian regolith would be the preferable starting point considering the abundance of carbon in the form of CO2 in the Martian atmosphere. It was proposed that carbon would be sourced from the cooling of carbon monoxide produced from CO2 electrolysis (MOXIE) from the Martian atmosphere. An Ellingham diagram showing the relative stability of oxides at Mars's atmospheric pressure of 7 mbar has been constructed; detailed equilibrium calculations to evaluate the carbothermic reduction of Martian regolith have also been carried out. The thermodynamic calculations predicted the formation of liquid Fe alloy with 99.9% conversion when the regolith was reacted with carbon (at approximately 10 wt% addition) at 1120 °C and 7 mbar. The impurities in the liquid Fe alloy were predicted to be mainly Si, C, Cr, and P. The hot gas produced from the process was predicted to be rich in CO (91%) and could be used for the preheating of the regolith. The CO could also be recycled and condensed to produce C (that could be re-used for the carbothermic reduction). The minimum energy requirement for the carbothermic reactor was calculated to be 3.37 MWh/tonne of liquid iron alloy (while the total energy requirement including MOXIE and agglomeration was calculated to be 15.51 MWh/tonne of liquid iron alloy). A generic process flowsheet has been developed considering these results.

Shock/expansion fan interaction with real gas effects for Earth and Mars atmospheric conditions

AbstractNumerical simulations are performed to investigate the real gas effects on shock/expansion fan interaction. Initial perfect gas simulations at low enthalpy capture the flow structures efficiently and outcomes are found to have excellent agreement with the analytical calculations. Furthermore, the simulations with the real gas solver for different enthalpies showed that the variation in enthalpy significantly changes the flow structures. It is observed that an increase in enthalpy leads to a decrease and increase in the postshock and postexpansion fan Mach numbers, respectively. Another important observation is the decrement in the peak pressure ratio with an increment in the enthalpy. These effects are noted to be more pronounced for Mars's environment due to the higher dependency of specific heat on temperature.

Transition of shock reflection at higher enthalpies for Earth and Mars atmospheres

Numerical investigation is performed for Mach reflection phenomena in Earth and Mars atmospheric conditions considering real gas effects. Initial computation at lower enthalpy yields Mach reflection in either flow medium. It is found that with increment in the freestream enthalpy the reflection pattern changes from Mach to regular reflection more prominently for the Mars atmosphere. This change is believed to be due to the noticeable real gas effects at higher enthalpies. The shock polar analyses indicate that the flow properties variation at higher enthalpies increases the maximum deflection angle of the flow, which in turn introduces transition in the reflection pattern.

Comparative studies of shock-wave boundary-layer interactions in Earth and Mars atmospheres

Investigations of ramp-induced shock-wave boundary-layer interaction have been carried out for real gas flows of air and carbon dioxide through hypersonic laminar flow simulations corresponding to Earth and Mars atmospheres. An in-house-developed solver, which accounts for the real gas effects, has been employed for these studies. Effects of various parameters like wall temperature, freestream stagnation enthalpy, freestream Mach number, and blunt leading edge are explored on the intensity of shock-wave boundary-layer interaction (SWBLI). In either case, an increase in separation length is observed with an increase in wall temperature and a decrease in Mach number as well as freestream stagnation enthalpy. Here, the intensity of alteration is always noted to have a higher percentage for the Mars gas model. Further, separation length is found to be almost equal for the same wall to total temperature ratio in both of the flow mediums. The present study also affirms the fact that the leading edge bluntness can be used as a tool to reduce the size of the separation region in these planetary atmospheres. Revised correlations have been proposed for hypersonic Earth atmospheric flow with real gas effects to predict the extent of upstream influence and separation bubble size. The outcomes of simulations have also helped to device new correlations for these flow features of SWBLI for Mars atmospheric conditions. In all, the need for consideration of real gas effects and an exclusive real gas flow solver for the Mars atmosphere are the prominent recommendations of current studies.

Discrete mechanics and optimal control optimization of flapping wing dynamics for Mars exploration

Mars exploration is currently in the focus of scientific community interests. The attempts for efficient exploration will probably include the unmanned aerial vehicle in the near future to explore the places inaccessible by rovers. Since the Mars atmospheric conditions render the conventional rotary and fixed wing aerial vehicles inefficient, the insect-type flapping concept emerged as a promising solution. This is due to the fact that insects on Earth fly efficiently at the same values of Reynolds number that the aerial vehicle for Mars exploration would exhibit. The paper proposes the novel design optimization algorithm for development of insect-type aerial vehicle capable of flight in Martian atmosphere. The optimization procedure utilizes the novel flapping pattern optimization based on a quasi-steady aerodynamic model, combined with the discrete mechanics and optimal control framework. A test case of a flapping vehicle with fruit fly-like wings, performing a standstill hovering on Mars, is analyzed in detail. The fruit fly wing is scaled with a wide range of uniform scaling factors and optimized for hovering on Mars in the conditions of bioinspired Reynolds number range. Apart from the single optimal combination for the standstill hovering with fruit fly-like wings, the algorithm also found different efficient flapping patterns for a wide range of scaling factors, providing directions for design of flapping aerial vehicles for Mars.

Design of a direct-detection wind and aerosol lidar for mars orbit

The present knowledge of the Mars atmosphere is greatly limited by a lack of global measurements of winds and aerosols. Hence, measurements of height-resolved wind and aerosol profiles are a priority for new Mars orbiting missions. We have designed a direct-detection lidar (MARLI) to provide global measurements of dust, winds and water ice profiles from Mars orbit. From a 400-km polar orbit, the instrument is designed to provide wind and backscatter measurements with a vertical resolution of 2 km and with resolution of 2° in latitude along track. The instrument uses a single-frequency, seeded Nd:YAG laser that emits 4 mJ pulses at 1064 nm at a 250 Hz pulse rate. The receiver utilizes a 50-cm diameter telescope and a double-edge Fabry-Pérot etalon as a frequency discriminator to measure the Doppler shift of the aerosol-backscatter profiles. The receiver also includes a polarization-sensitive channel to detect the cross-polarized backscatter profiles from water ice. The receiver uses a sensitive 4 × 4 pixel HgCdTe avalanche photodiode array as a detector for all signals. Here we describe the measurement concept, instrument design, and calculate its performance for several cases of Mars atmospheric conditions. The calculations show that under a range of atmospheric conditions MARLI is capable of measuring wind speed profiles with random error of 2–4 m/s within the first three scale heights, enabling vertically resolved mapping of transport processes in this important region of the atmosphere.

Performance assessment of energy deposition based drag reduction technique for Earth and Mars flight conditions

Energy deposition based drag reduction technique is numerically investigated for Earth and Mars atmospheric conditions using in-house non-equilibrium flow solvers. Golden section search algorithm is successfully integrated with these CFD solvers to evaluate the optimum amount of energy to be deposited for maximum power effectiveness. During these studies for spherical configuration, it has been noticed that, the amount of energy deposited corresponding to maximum power effectiveness is more for Mars case than the Earth case. Higher temperature dependence of specific heat for carbon dioxide than air is accounted to be responsible for this observation. Further, maximum power effectiveness is marked to be lower for carbon dioxide flow as compared to that for air flow. It has also been noticed that the performance of this technique gets lowered with increase in stagnation enthalpy of the flow, in either cases, with remarkable drop in case of air.

Design of a Mars atmosphere simulation chamber and testing a Raman Laser Spectrometer (RLS) under conditions pertinent to Mars rover missions

Raman spectrometry is a powerful technique for the rapid identification of most minerals and organic chemicals without sample preparation. In this context, the European Space Agency (ESA) and NASA selected a Raman spectrometer in the payload of the future ExoMars and Mars 2020 missions to identify organic compounds and mineral products indicative of biological activity on Mars. Little is known, however, about the effects of Mars atmospheric conditions on instrument performance and on the Raman spectra. The objective of this study was to i) design and construct a versatile simulation chamber to reproduce the atmospheric conditions expected inside a rover on Mars, ii) to test the performance of a previously designed breadboard miniaturized Raman laser spectrometer (RLS) inside the chamber. The Mars Atmosphere Simulation Chamber (MASC) is a temperature and atmosphere controlled chamber. It includes an innovative heating-cooling system to create homogeneous temperatures inside the chamber that can be varied between 243 K and 283 K, while the charged coupled device (CCD) of the Raman spectrometer can be independently cooled (e.g., 233 K). A vacuum and gas control system permits evacuation of the chamber and the subsequent introduction of any (dried) gas mixture at partial pressures between 1 mbar and several bars. The minimum CCD temperature was found to depend on the surrounding MASC temperature and atmosphere. A vertical shift of 3 pixels on the CCD was observed for the Raman signals upon lowering the temperature from 283 to 253 K. We show that the RLS instrument gives reliable Raman spectra over the tested range of temperatures and from a vacuum of 4 x 10−5 mbar to a CO2 atmosphere at pressure relevant to Mars (8 mbar). For example, the Raman spectra of three test minerals, calcite, aragonite and baryte, showed identifiable Raman peaks with Raman shift values within ± 1 cm−1 of those reported in previous works under terrestrial conditions. This confirms that a RLS instrument is useful for the identification of minerals during future missions to Mars; once a necessary detector recalibration was carried out, the system performed well under 8 mbar pressure and 243 – 283 K. The MASC was found to be a versatile instrument; it can provide important information on instrument performance under Martian conditions and other temperatures and atmospheric conditions can also be simulated.

CFD Analysis of Mars Phoenix Capsules at Mach Number 10

Numerical simulations are performed for flow over Phoenix entry vehicle at Mars at zero angle of Attack and Mach number 10. Flow field features like bow shock, shear layers, expansion fan and separation bubble will be captured using CFD commercial package FLUENT. The computed wall data of pressure and temperature will be compared with experimental results at Mars atmospheric conditions. This project deals with the study of flow over Phoenix entry vehicle at Mach number 10. The concept of atmospheric entry has applications in various fields. Vehicles that typically undergo this process include exo-orbital trajectories. In this project, the type of entry vehicle considered is entry capsule, which enters Mars atmosphere from an orbit. The primary design consideration of entry capsule requires large spherical nose radius of their fore body that gives high aerodynamic drag and a short body length for reducing the total structural weight and the ballistic coefficient.

Development of a fast, accurate radiative transfer model for the Martian atmosphere, past and present

We present details of an approach to creating ak‐distribution radiative transfer model (KDM) for use in the Martian atmosphere. Such models preserve the accuracy of more rigorous line‐by‐line models, but are orders of magnitude faster, and can be effectively implemented in 3‐D general circulation models. The approach taken here is sufficiently generalized that it can be employed for atmospheres of any arbitrary composition and mass, and demonstrations are provided for simulated atmospheres with a present‐day Martian surface pressure (∼6 mb) and a putative thick early Mars atmosphere (∼500 mb), both with and without atmospheric water vapor. KDM‐derived absorption coefficients are placed into a look‐up table at a set of gridded points in pressure, temperature and atmospheric composition, and a tri‐linear interpolation scheme is used to obtain the coefficients appropriate for the local atmospheric conditions. These coefficients may then be used within any of a variety of commonly used flux solvers to obtain atmospheric heating rates. A series of validation tests are performed with the KDM for both present‐day and early Mars atmospheric conditions, and the model is compared against several other widely used radiative transfer schemes, including several used in contemporary general circulation models. These validation results identify weaknesses in some other approaches and demonstrate the efficacy of the KDM, providing a rigorous test of these types of models for use in the Martian atmosphere. A demonstration of results obtained by implementing the KDM in a Mars general circulation model is provided.

Extraction of compositional and hydration information of sulfates from laser-induced plasma spectra recorded under Mars atmospheric conditions — Implications for ChemCam investigations on Curiosity rover

Given the volume of spectral data required for providing accurate compositional information and thereby insight in mineralogy and petrology from laser-induced breakdown spectroscopy (LIBS) measurements, fast data processing tools are a must. This is particularly true during the tactical operations of rover-based planetary exploration missions such as the Mars Science Laboratory rover, Curiosity, which will carry a remote LIBS spectrometer in its science payload. We have developed: an automated fast pre-processing sequence of algorithms for converting a series of LIBS spectra (typically 125) recorded from a single target into a reliable SNR-enhanced spectrum; a dedicated routine to quantify its spectral features; and a set of calibration curves using standard hydrous and multi-cation sulfates. These calibration curves allow deriving the elemental compositions and the degrees of hydration of various hydrous sulfates, one of the two major types of secondary minerals found on Mars. Our quantitative tools are built upon calibration-curve modeling, through the correlation of the elemental concentrations and the peak areas of the atomic emission lines observed in the LIBS spectra of standard samples. At present, we can derive the elemental concentrations of K, Na, Ca, Mg, Fe, Al, S, O, and H in sulfates, as well as the hydration degrees of Ca- and Mg-sulfates, from LIBS spectra obtained in both Earth atmosphere and Mars atmospheric conditions in a Planetary Environment and Analysis Chamber (PEACh). In addition, structural information can be potentially obtained for various Fe-sulfates.

Chemical pathway analysis of the lower Martian atmosphere: The CO2 stability problem

The chemical composition and hence the structure of terrestrial planetary atmospheres can be critically controlled by trace species which can act in catalytic cycles. Identifying such chemical pathways is in general challenging. Due to the complexity of chemical reaction networks, like those used in Martian atmospheric chemistry, automated methods become more and more useful to cope with this task. Here, we investigate the applicability of a unique analysis tool PAP (Pathway Analysis Program) to the chemistry at Mars' atmospheric surface conditions, for which we have developed a photochemical box-model. PAP is applied for the first time to the output of this model to investigate the well-known CO2 stability problem of the Martian atmosphere. We identify and rank the most dominant pathways responsible for CO2 formation and prove thereby the applicability of PAP for Mars atmospheric conditions by comparison with known chemical cycles. Furthermore, we propose here an additional new catalytic CO2 formation cycle which is also involved in the production of ozone.

Optimization of laser-induced breakdown spectroscopy for rapid geochemical analysis

Laser-induced breakdown spectroscopy (LIBS) is demonstrated as a quantitative technique for geochemical analysis. This study demonstrates the applicability of LIBS to bulk elemental analysis of igneous rock powders. LIBS spectra of 100 igneous rocks with highly varying compositions were acquired at 9 m standoff distance under Mars atmospheric conditions. LIBS spectra were modeled using partial least squares regressions to predict major element compositions. A series of comparative tests determined the most effective methodologies for pre-processing of spectral and compositional data, and choice of calibration set. In the best cases, calculated 1− σ errors are 1.6 wt.% SiO 2, 1.5 wt.% Al 2O 3, 0.4 wt.% TiO 2, 1.2 wt.% Fe 2O 3T, 1.6 wt.% MgO, 0.02 wt.% MnO, 1.1 wt.% CaO, 0.5 wt.% Na 2O, 0.2 wt.% P 2O 5, and 0.4 wt.% K 2O, with totals near 100%. The largest improvement came as a result of scaling the elemental distributions to equalize the ranges of variability. Optimal predictions for this data set were produced with calibration set compositions input as weight % oxides and not atomic fractions. Predictions were also improved when calibration sets represented the smallest range of compositional variability possible, and completely encompassed the compositional range encountered. Multiple calibration sets relevant to different rock types are preferred over a single all-encompassing calibration set. Baseline removal and transforming spectral data by their first derivative do not improve predictions and can even have negative effects. These results are directly applicable to spectra that will be acquired by the ChemCam experiment on Mars Science Laboratory, but also apply more broadly to terrestrial LIBS applications.

Protection of chemolithoautotrophic bacteria exposed to simulated Mars environmental conditions

Current surface conditions (strong oxidative atmosphere, UV radiation, low temperatures and xeric conditions) on Mars are considered extremely challenging for life. The question is whether there are any features on Mars that could exert a protective effect against the sterilizing conditions detected on its surface. Potential habitability in the subsurface would increase if the overlaying material played a protective role. With the aim of evaluating this possibility we studied the viability of two microorganisms under different conditions in a Mars simulation chamber. An acidophilic chemolithotroph isolated from Río Tinto belonging to the Acidithiobacillus genus and Deinococcus radiodurans, a radiation resistant microorganism, were exposed to simulated Mars conditions under the protection of a layer of ferric oxides and hydroxides, a Mars regolith analogue. Samples of these microorganisms were exposed to UV radiation in Mars atmospheric conditions at different time intervals under the protection of 2 and 5 mm layers of oxidized iron minerals. Viability was evaluated by inoculation on fresh media and characterization of their growth cultures. Here we report the survival capability of both bacteria to simulated Mars environmental conditions.

Stability of liquid saline water on present day Mars

Perchlorate salts (mostly magnesium and sodium perchlorate) have been detected on Mars' arctic soil by the Phoenix lander, furthermore chloride salts have been found on the Meridiani and Gusev sites and on widespread deposits on the southern Martian hemisphere. The presence of these salts on the surface is not only relevant because of their ability to lower the freezing point of water, but also because they can absorb water vapor and form a liquid solution (deliquesce). We show experimentally that small amounts of sodium perchlorate (∼ 1 mg), at Mars atmospheric conditions, spontaneously absorb moisture and melt into a liquid solution growing into ∼ 1 mm liquid spheroids at temperatures as low as 225 K. Also mixtures of water ice and sodium perchlorate melt into a liquid at this temperature. Our results indicate that salty environments make liquid water to be locally and sporadically stable on present day Mars.

Evaluation of a compact spectrograph for in-situ and stand-off Laser-Induced Breakdown Spectroscopy analyses of geological samples on Mars missions

Laser-induced Breakdown Spectroscopy (LIBS) is actively under development for future use on surface probes to Mars. The analytical method can be deployed for in-situ and/or stand-off analysis with the latter embodiment providing the greatest advantages compared to previous and current elemental analysis methods used for planetary surface analysis. For this application, LIBS must be thoroughly investigated in terms of analytical capabilities and flight-rated instruments must be developed. Because of the low pressure of the predominantly CO 2 atmosphere on Mars, studies are needed to understand analytical requirements and to determine performance under these conditions. Stand-off analysis demands the most stringent requirements on instrumentation. Therefore, it must be determined if the high performance components that are normally used in a typical LIBS laboratory setup, which are generally not optimized for small size and weight, are essential to obtain the maximum scientific return from a mission. A key component of a LIBS apparatus is the detection system consisting of a spectrograph and a detector. Here we present an evaluation of one design of a compact spectrograph (Ocean Optics HR2000) for in-situ and stand-off LIBS analyses of geological samples under Mars atmospheric conditions.

Indications of sulfate minerals in the Martian soil from Earth‐based spectroscopy

Telescopic measurements of Mars between 4.40 and 5.13 μm at a spectral resolution (λ/Δλ) of 300 were made on August 19, 1988, UT at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. This wavelength region contains radiation from both solar reflection and thermal emission. Additionally, the Martian atmosphere has numerous atmospheric gas absorption features, dominated by the 4.2‐μm CO2 fundamental band. The Mars spectrum rise out of the 4.2 to 4.4‐μm CO2 band on the long‐wavelength side cannot be matched solely by atmospheric gas constituents. An absorption must be added at roughly 4.5 μm in order to decrease the reflectance rise and produce the 4.5‐μm inflection which is present in the data. The location of this feature at the position of the 2v3 overtone of the SO42− anion indicates that the surface absorption is probably caused by sulfates on the Martian surface and/or in atmospheric dust. This is consistent with the known presence of sulfates on the Martian surface from the Viking results. An exact spectral match to a terrestrial sulfur mineral has not been made, but we suggest that the mineral on Mars has very weak band structure, probably due to an ion environment in the mineral with a high degree of electric field symmetry. Significant variation exists at 4.5 μm among the observed spectra for different locations on Mars. In order of strength, from strongest absorption to weakest, are Eastern Solis Planum, Argyre Basin, Eastern Tharsis, and Valles Marineris for the four regions measured at similar Mars atmospheric conditions.