Mars Exploration Rover Research Articles

Interrelationships in the Gypsum–Syngenite–Görgeyite System and Their Possible Formation on Mars

Calcium sulfates are known to be potential reservoirs of organic compounds and have been detected on Mars. However, not all data that indicate the presence of sulfates collected by the Mars Exploration Rovers (Spirit and Opportunity) and Curiosity rover can be explained by the different calcium sulfate polymorphs, and therefore, mixtures of calcium sulfates with other single sulfates must be considered. In addition, the presence of mixed calcium sulfates supports the data and indicates that the molar ratio of sulfate/calcium is >1. To obtain adequate spectroscopic information of mixed-cation sulfates to be used in the interpretation of data from Mars in the next few years, the thermodynamically stable syngenite (K2Ca(SO4)2·H2O) and görgeyite (K2Ca5(SO4)6·H2O) mixed-cation sulfates have been studied along with the interrelationships in the gypsum-syngenite-görgeyite system to understand their possible formation on Mars. Raman spectroscopy and Visible-Near Infrared-Shortwave Infrared (VisNIR) spectroscopy have been used for their characterization to increase the databases for the two future Mars exploration missions, Mars2020 and ExoMars2022, where both techniques will be implemented. These VisNIR data can also help with the interpretation of spectral data of salt deposits on Mars acquired by the OMEGA and CRISM spectrometers onboard the Mars Express and Mars Reconnaissance orbiters. This work demonstrates that syngenite (K2Ca(SO4)2·H2O) easily precipitates without the need for hydrothermal conditions, which, depending on the ion concentrations, may precipitate in different proportions with gypsum. Furthermore, in this study, we also demonstrate that, under hydrothermal conditions, görgeyite (K2Ca5(SO4)6·H2O) would also be highly likely to form and may also be identified on Mars together with syngenite and gypsum.

Spectrophotometric properties of materials observed by Pancam on the Mars Exploration Rovers: 4. Final mission observations

The last sets of Panoramic Camera (Pancam) visible/near-infrared (432–1009 nm) multispectral observations made under varying viewing and illumination geometries by the Mars Exploration Rovers Spirit and Opportunity were examined using radiative transfer models to study the surface scattering and microphysical nature of rock and soil units at both sites. Nearly 12,000 individual measurements were collected for this study of soil, dust, and rock units over phase angles of ~0° to ~150°. Images were acquired on sols 1944–1946 (June 2009) at Troy, the final resting place of Spirit on the western side of Home Plate in Gusev crater, and by Opportunity at three locations on the western rim of Endeavour crater in Meridiani Planum between sols 2785 (November 2011) and 3867 (December 2014). Sky models were developed from observations of atmospheric opacity, which enabled corrections for diffuse skylight when combined with surface facet orientations determined from stereo images. Model results were improved by removing data affected by scattered light evident in some high phase angle images (resulting from minor dust contamination on the camera windows). At Troy, relatively dust-free “gray” rock units exhibited narrow, forward scattering behaviors akin to previous analyses of similar gray rock units at Gusev crater. Soils and “red” rocks coated with greater amounts of dust were more backscattering. Red rocks exhibited higher single scattering albedo (w), macroscopic roughness (θ), and opposition effect width (h) parameters, indicative of rough, low-porosity surfaces perhaps with more uniform grain size distributions. At Meridiani Planum, rubbly soils near São Gabriel crater and Cape Tribulation exhibited w values typical of previous soil analyses. However, the large drift “dust” deposits found in depressions on the northern tip of Cape York near Turkey Haven demonstrated elevated w values with a downturn toward 1009 nm, consistent with minor hydration of these materials. The dust deposits were modeled with the lowest θ values and highest h values of all soil units analyzed during the Opportunity mission, indicative of a smooth surface with homogeneous grain size distribution and/or lower porosity than other units. The dust unit scattering function was dissimilar to those for atmospheric and airfall-deposited dusts, however, suggesting that the originally deposited materials had been modified, perhaps by hydration and ongoing aeolian effects. Analyses of phase curve ratios among the units studied here and from laboratory data of analog soils suggested that surface scattering is a major control on the peak phase angle position of the “arch” in phase curve ratios, alongside the effects of particle-scale roughness.

A study of photovoltaic degradation modes due to dust interaction on Mars

We explored the utility of ground-based highly accelerated life testing (HALT) on triple-junction coverglass interconnected cells (CICs) after exposure to Mars dust storm conditions. The CICs comprised the triple junction solar cells, a silicone encapsulant bonded to ceria-doped coverglass with an antireflection coating. These CICs were placed in an enclosure and sandblasted with Mars dust simulant to replicate dust impingement. We compared the apparatus properties with measured Martian dust storm parameters from Viking landers. We found that simulated Martian dust storms often result in increased reflectance and decreased absorption at visible wavelengths and subsequent reduced short circuit current (JSC). Reduction in the open circuit voltage (VOC) is observed in select cases, caused by structural damage after CIC fracture. We found that even if there is no observable VOC losses, minority carrier lifetime is reduced. The JSC tends to rebound upon cleaning, suggesting current losses are reversible and unrelated to permanent damage such as cell cracking and subsequent isolation of regions of the cell due to broken busbars. This observation indicates a quantifiable difference between recoverable and non-recoverable power loss, suggesting a permanent degradation could be determined. We compared experimental data to mined field data from the Mars Exploration Rover, Opportunity and extracted a degradation rate. We found exceptional agreement between the irreversible degradation in our laboratory experiments and 4.9 Martian years of mined field data, 9.7% and 9.4% respectively, demonstrating that the laboratory method well represents the physical reality of solar cells’ exposure to the Martian environment.

How Good is “Good Enough?” Major Element Chemical Analyses of Planetary Basalts by Spacecraft Instruments

Abstract Bulk chemical composition is a fundamental property of a planetary material, rock or regolith, and can be used to constrain the properties and history of a material, and by extension its parent body, including its potential for habitability. Here, we investigate how uncertainties in bulk major element analyses can affect inferences derived from those analyses, including rock classification by total-alkalis–silica (TAS); Chemical Index of Alteration (CIA); a tectonic discriminant for magma genesis; and the inferred mantle pressure and temperature of a basaltic magma’s origin. Uncertainties for actual spacecraft instruments (Mars Exploration Rover and Mars Science Laboratory (MER/MSL), Alpha Proton X-Ray Spectroscopy (APXS), and Mars Science Laboratory: Laser-Induced Breakdown Spectroscopy (MSL LIBS)) and a suggested uncertainty level for analyses on Venus (Venus Exploration Targets (VExT) Workshop) are higher than those of standard Earth-based analyses (e.g., by inductively coupled plasma optical emission spectrometry (ICPOES)). We propagate the uncertainties from each analysis type to the derived parameters, both implicitly and via boot-strap (Monte Carlo) methods. Our calculations show that the uncertainties of APXS and VExT are greater than those for ICPOES, but they still allow useful inferences about rock type and history. Our results show that the uncertainties of MSL LIBS analyses are significantly larger than the other techniques, and can provide only limited constraints on rock types or histories. Any instruments chosen for future mission must have uncertainties of the chemical analyses small enough to meet the mission’s overall scientific objectives.

Wheels' performance of Mars exploration rovers: Experimental study from the perspective of terramechanics and structural mechanics

The soft ground and stones on the surface of Mars may cause sinkage of and damage to the wheels of a Mars rover. Therefore, we analyzed the performance of a wheel-step Mars rover from the perspective of terramechanics and structural mechanics. Using China’s Mars rover wheel prototype and wheel-soil interaction testbed, we obtained the driving performance of the wheels of a Mars rover under various conditions, including full skidding conditions. The vertical load set in the tests was determined using the gravity of Mars and the mass of the wheel-step Mars rover. The results indicate that the driving torque, sinkage, and resistance coefficient have a linear relationship with the wheel vertical load. An analysis of the structural mechanical characteristics of the wheel of the Mars rover was conducted by testing the radial, axial, torsional, and deflection stiffness. We found that the wheel ribs can improve the stiffness of the wheel but may reduce its driving performance. The analysis methods and evaluation indices can be used to analyze the performance of the wheels of other Mars rovers. Furthermore, the findings of this study can be used to optimize wheel design and motion control of wheel-step Mars exploration rovers.

Assessment of InSight Landing Site Predictions.

Comprehensive analysis of remote sensing data used to select the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) landing site correctly predicted the atmospheric temperature and pressure profile during entry and descent, the safe landing surface, and the geologic setting of the site. The smooth plains upon which the InSight landing site is located were accurately predicted to be generally similar to the Mars Exploration Rover Spirit landing site with relatively low rock abundance, low slopes, and a moderately dusty surface with a 3–10 m impact fragmented regolith over Hesperian to Early Amazonian basaltic lava flows. The deceleration profile and surface pressure encountered by the spacecraft during entry, descent, and landing compared well (within 1σ) of the envelope of modeled temperature profiles and the expected surface pressure. Orbital estimates of thermal inertia are similar to surface radiometer measurements, and materials at the surface are dominated by poorly consolidated sand as expected. Thin coatings of bright atmospheric dust on the surface were as indicated by orbital albedo and dust cover index measurements. Orbital estimates of rock abundance from shadow measurements in high‐resolution images and thermal differencing indicated very low rock abundance and surface counts show 1–4% area covered by rocks. Slopes at 100 to 5 m length scale measured from orbital topographic and radar data correctly indicated a surface comparably smooth and flat as the two smoothest landing sites (Opportunity and Phoenix). Thermal inertia and radar data indicated the surface would be load bearing as found.

Design and Concept of Rocker-Bogie Suspension for a Planetary Rover Prototype

In light of the notable rocker-bogie mechanism, this paper shows an ideal plan of a rocker-bogie suspension framework so as to ensure high mobile steadiness as well as excellent versatility of a prototype rover vehicle while traversing through rough terrains. It is essentially a suspension arrangement utilized in mechanical automated vehicles utilized explicitly for space investigation. The rocker-bogie suspension-based rovers have been effectively presented for the Mars Pathfinder and Mars Exploration Rover (MER) and Mars Science Laboratory (MSL) missions led by zenith space investigation laboratories all through the world. The proposed suspension framework is presently the most supported structure for each space investigation organization. It is basically a mechanism which comprises of two arms with wheel mounted to each and the two arms are associated through a versatile joint. The current development in design has been studied as well as a different approach towards designing the basic structure of suspension has been done. It has been further verified using various static and dynamic load calculations, solid modelling computer aided design software and simulation software for analysis and testing.

Draft Genome Sequences of Bacillus glennii V44-8, Bacillus saganii V47-23a, Bacillus sp. Strain V59.32b, Bacillus sp. Strain MER_TA_151, and Paenibacillus sp. Strain MER_111, Isolated from Cleanrooms Where the Viking and Mars Exploration Rover Spacecraft Were Assembled.

We report the draft genome sequences of Bacillus glennii V44-8, Bacillus saganii V47-23a, and Bacillus sp. strain V59.32b, isolated from the Viking spacecraft assembly cleanroom, and Bacillus sp. strain MER_TA_151 and Paenibacillus sp. strain MER_111, isolated from the Mars Exploration Rover (MER) assembly cleanroom.

A Study on Rocker-Bogie Suspension for a Planetary Rover Prototype

In light of the notable rocker-bogie mechanism, this paper shows an ideal plan of a rocker-bogie suspension framework so as to ensure high mobile steadiness as well as excellent versatility of a prototype rover vehicle while traversing through rough terrains. It is essentially a suspension arrangement utilized in mechanical automated vehicles utilized explicitly for space investigation. The rocker-bogie suspension-based rovers have been effectively presented for the Mars Pathfinder and Mars Exploration Rover (MER) and Mars Science Laboratory (MSL) missions led by zenith space investigation laboratories all through the world. The proposed suspension framework is presently the most supported structure for each space investigation organization. It is basically a mechanism which comprises of two arms with wheel mounted to each and the two arms are associated through a versatile joint. The current development in design has been studied as well as a different approach towards designing the basic structure of suspension has been done. It has been further verified using various static and dynamic load calculations, solid modelling computer aided design software and simulation software for analysis and testing.

Research of flexible wheels assumed for Mars exploration rover

Research of flexible wheels assumed for Mars exploration rover

The Italian Solfatara as an analog for Mars fumarolic alteration

AbstractThe first definitive evidence for continental vents on Mars is the in situ detection of amorphous silica-rich outcrops by the Mars Exploration Rover Spirit. These outcrops have been tentatively interpreted as the result of either acid sulfate leaching in fumarolic environments or direct precipitation from hot springs. Such environments represent prime targets for upcoming astrobiology missions but remain difficult to identify with certainty, especially from orbit. To contribute to the identification of fumaroles and hot spring deposits on Mars, we surveyed their characteristics at the analog site of the Solfatara volcanic crater in central Italy. Several techniques of mineral identification (VNIR spectroscopy, Raman spectroscopy, XRD) were used both in the field and in the laboratory on selected samples. The faulted crater walls showed evidence of acid leaching and alteration into the advanced argillic-alunitic facies, with colorful deposits containing alunite, jarosite, and/or hematite. Sublimates containing various Al and Fe hydroxyl-sulfates were observed around the active fumarole vents at 90 °C. One vent at 160 °C was characterized by different sublimates enriched in As and Hb sulfide species. Amorphous silica and alunite assemblages that are diagnostic of silicic alteration were also observed at the Fangaia mud pots inside the crater. A wide range of minerals was identified at the 665 m diameter Solfatara crater that is diagnostic of acid-steam heated alteration of a trachytic, porous bedrock. Importantly, this mineral diversity was captured at each site investigated with at least one of the techniques used, which lends confidence for the recognition of similar environments with the next-generation Mars rovers.

MARSWRF Prediction of Entry Descent Landing Profiles: Applications to Mars Exploration

AbstractIn this paper we use the Mars implementation of the Planet Weather Research and Forecasting model, MarsWRF, to simulate the Entry, Descent and Landing (EDL) vertical profiles from six past missions: Pathfinder, Mars Exploration Rovers Opportunity and Spirit, Phoenix, Mars Science Laboratory Curiosity rover, and ExoMars 2016 (Schiaparelli), and compare the results with observed data. In order to investigate the sensitivity of the model predictions to the atmospheric dust distribution, MarsWRF is run with two prescribed dust scenarios. It is concluded that the MarsWRF EDL predictions can be used for guidance into the design and planning stage of future missions to the planet, as it generally captures the observed EDL profiles, although it has a tendency to underestimate the temperature and overestimate the density for heights above 15 km. This could be attributed to an incorrect representation of the observed dust loading. We have used the model to predict the EDL conditions that may be encountered by two future missions: ExoMars 2020 and Mars 2020. When run for Oxia Planum and Jezero Crater for the expected landing time, MarsWRF predicts a large sensitivity to the dust loading in particular for the horizontal wind speed above 10‐15 km with maximum differences of up to ±30 m/s for the former and ±15 m/s for the latter site. For both sites, the best time for EDL, that is, when the wind speed is generally the weakest with smaller shifts in direction, is predicted to be in the late morning and early afternoon.

Effects of the MY34/2018 Global Dust Storm as Measured by MSL REMS in Gale Crater

The Rover Environmental Monitoring Station (REMS) instrument that is onboard NASA's Mars Science Laboratory (MSL) Curiosity rover. REMS has been measuring surface pressure, air and ground brightness temperature, relative humidity, and UV irradiance since MSL's landing in 2012. In Mars Year (MY) 34 (2018) a global dust storm reached Gale Crater at Ls ~190°. REMS offers a unique opportunity to better understand the impact of a global dust storm on local environmental conditions, which complements previous observations by the Viking landers and Mars Exploration Rovers. All atmospheric variables measured by REMS are strongly affected albeit at different times. During the onset phase, the daily maximum UV radiation decreased by 90% between sols 2075 (opacity ~1) and 2085 (opacity ~8.5). The diurnal range in ground and air temperatures decreased by 35K and 56K, respectively, with also a diurnal-average decrease of ~2K and 4K respectively. The maximum relative humidity, which occurs right before sunrise, decreased to below 5%, compared with pre-storm values of up to 29%, due to the warmer air temperatures at night while the inferred water vapor abundance suggests an increase during the storm. Between sols 2085 and 2130, the typical nighttime stable inversion layer was absent near the surface as ground temperatures remained warmer than near-surface air temperatures. Finally, the frequency-domain behavior of the diurnal pressure cycle shows a strong increase in the strength of the semidiurnal and terdiurnal modes peaking after the local opacity maximum, also suggesting differences in the dust abundance inside and outside Gale.

Fixed-time pinpoint mars landing using two sliding-surface autonomous guidance

Autonomous powered-descent guidance algorithm for the pinpoint Mars landing in the presence of various disturbances and uncertainties is necessary for next-generation Mars exploration rover mission. This paper proposes a novel two sliding-surfaces guidance scheme based on fixed-time stabilization technique, which is robust against unknown Martian atmospheric disturbances (with known upper bound). For a fixed-time pinpoint landing mission, the main advantage of the proposed guidance is that the landing mission reliability can be ensured that Martian surface collision would never encounter. The fuel efficiency can be guaranteed in the comparison with the offline fuel optimal solution. The capacity of avoiding collisions is guaranteed by the monotonic convergence design of the proposed sliding modes. Lyapunov stabilization theory is adopted to prove the global stability of the proposed guidance. Monte Carlo numerical simulations are implemented in a realistic scenario and the results confirm the collision avoidance capability, the fuel efficiency and the robustness of the proposed guidance.

Magnetic Mars dust-removal technology

Environmental data recorded by the Mars exploration rovers show that the martian dust is magnetic containing mostly the strong magnetic mineral magnetite ( $${\text {Fe}}_3{\text {O}}_4$$ ). On the other hand, it is known that dust settling onto the surface of solar arrays can affect the utility on solar power on any Mars mission, and particulary for long-term operation. Dust obscuration of solar arrays can be a special issue for the case of a future 6-month sample fetching rover (SFR) mission, where the current baseline architecture contemplates the use of solar array and where dust storms can jeopardize the entire mission, not only affecting the supply of energy for locomotion but for the communication with the Mars ascent vehicle (MAV). Today, available dust-removal techniques have been classified into four categories: natural, mechanical, electromechanical, and electrostatic. However, by aforementioned, an additional category may be included in this portfolio based in the magnetic properties of the martian dust. Here a first scoping study for a magnetic Mars dust technology is outlined. Finally, a specific ad hoc magnetic technology is proposed an analyzed.

Overview of Spirit Microscopic Imager Results

AbstractThis paper provides an overview of Mars Exploration Rover Spirit Microscopic Imager (MI) operations and the calibration, processing, and analysis of MI data. The focus of this overview is on the last five Earth years (2005–2010) of Spirit's mission in Gusev crater, supplementing the previous overview of the first 450 sols of the Spirit MI investigation. Updates to radiometric calibration using in‐flight data and improvements in high‐level processing are summarized. Released data products are described, and a table of MI observations, including target/feature names and associated data sets, is appended. The MI observed natural and disturbed exposures of rocks and soils as well as magnets and other rover hardware. These hand‐lens‐scale observations have provided key constraints on interpretations of the formation and geologic history of features, rocks, and soils examined by Spirit. MI images complement observations by other Spirit instruments, and together show that impact and volcanic processes have dominated the origin and evolution of the rocks in Gusev crater, with aqueous activity indicated by the presence of silica‐rich rocks and sulfate‐rich soils. The textures of some of the silica‐rich rocks are similar to terrestrial hot spring deposits, and observations of subsurface cemented layers indicate recent aqueous mobilization of sulfates in places. Wind action has recently modified soils and abraded many of the rocks imaged by the MI, as observed at other Mars landing sites.

An Instrument Anomaly in the Mars Exploration Rover Pancam 1,009‐nm Filter (R7): Characterization, Simulation, Correction, and Preliminary Verification

During pre‐flight calibration of the panoramic camera (Pancam) instrument on board the Mars Exploration Rovers MER A (Spirit) and MER B (Opportunity), a discrepancy was noted between 11‐band spectra extracted from Pancam images of the camera's radiometric calibration target and reflectance spectra obtained with a spectrometer. This discrepancy was observed in the longest‐wavelength filter of the camera (the longpass R7 filter with system λeff = 1,009 nm) and consisted of a reduction in contrast between bright and dark regions. Here we describe and characterize this effect. We propose that the effect arises because long‐wavelength photons close to the silicon band‐gap at 1,100 nm are allowed through the R7 filter, pass through the bulk charge‐coupled device, scatter from the backside, pass through the charge‐coupled device again, and are registered in a pixel other than the pixel through which they originally entered. Based on this hypothesis we develop a model capable of accurately simulating the effect, and correct for it. We present preliminary results from testing this correction on preflight, as well as in‐flight, images. The effect is small, but in some specific cases in small regions of high contrast, the effect is significant. In in‐flight images of Martian terrain we observed the signal in dark shadows to be artificially inflated by up to ∼ 33% and analysis of early‐mission calibration target images indicated that the reduced contrast due to the artifact is equivalent to >100 DN (full well = 4095 DN) for a hypothetical perfectly dark pixel.

Study of Mars Exploration Rover get over step by hinge mechanism of center of gravity

Study of Mars Exploration Rover get over step by hinge mechanism of center of gravity

About the Space Robots

Today, robots help us more than ever in all major operations, everyday life and become a daily reality, making it an integral part of major human projects. If they are still the majority in the machine industry, they will soon become as many in other industries and at the same time will grow strongly for human support in conquering extraterrestrial space in an extended campaign robot will have a role. We already have orbital space stations with robots, followed by others in the form of colonies on the Moon and on Mars and then a continuous expansion. At the same time, the expansion of scientific research and robot exploration, which has already exceeded the limits of our solar system, but unfortunately the power of the fission power fission, does not allow the probe to have greater autonomy at this time, which is imperative plus the development of robotic and automated systems to create new spatial energy sources. Opportunity (known as MER-B) or MER-1, called Oppy, is a robotic engine fueled from 2004 until the end of 2018. At NASA, Mars Exploration Rover landed at Meridiani Planum on January 25, 2009, ceased to communicate in 2010, while Opportunity managed to remain operational for an area of 5111 meters after landing, recharging solar batteries and hibernation storms. This careful operation allowed Opportunity to exceed its operating plan by 14 years, 46 days (during the Earth), 55 times the projected lifespan. Until June 10, 2018, when he first contacted NASA, Rover traveled at a distance of 45.16 km. The most important missions included the initial 90-mile mission, finding extramarital meteorites such as the Rock of Heat Shield and over two years exploring and studying Crater Victoria. Rover survived the moderate dust storms and in 2011 reached the Endeavor crater, which was described as the second place to land. The Opportunity mission is considered one of NASA's most successful adventures. Curiosity is a small machine designed to explore the Mars Gale Crater within the NASA mission, Mars Science Laboratory (MSL). Curiosity was launched from Cape Canaveral on November 26, 2011, at 15:02 UTC and landed on Aeolis Palus in Gale on Mars on August 6, 2012, at 5:17 UTC. The Bradbury Landing Point was less than 2.4 km (1.5 mi) from the rover's target center after a 560-million-mile journey. The objectives of the rover include an investigation into Martian climate and geology; assessing whether the site selected in Gale has ever provided environmentally friendly environmental conditions for microbial life, including investigating the role of water; and studies on planetary habitats in preparation for human exploration.

The Experience of Presence in the Mars Exploration Rover Mission

Abstract Scientists working in the Mars Exploration Rover (MER) mission (2004–2018) reported having a sense of presence on Mars. How is this possible, given that many of the factors underlying presence in mundane situations were absent? We use Riva and Waterworth's (2014) Three-Level model to elucidate how presence was achieved. It distinguishes among proto-presence, core-presence, and extended-presence. We argue that scientists did not experience proto-presence because it requires a tight sensorimotor coupling not available due to the way the rovers were controlled and due to the lengthy delays in getting feedback. Instead, the design of the sociotechnical system made core-presence and extended-presence possible. Extended-presence involved successfully establishing long-term conceptual goals during strategic planning meetings. Core-presence involved enacting short-term tactical goals by carrying out specific actions on particular targets, abstracting away from sensorimotor details. The shift of perspective to the Martian surface was facilitated by team members “becoming the rover,” which allowed them to identify relevant affordances evident in images. We argue, however, that because Mars exploration is a collective activity involving shared agency by a distributed cognitive system, the experience of core- and extended-presence was a collective sense of presence through the rovers.