43 research outputs found
Terrain physical properties derived from orbital data and the first 360 sols of Mars Science Laboratory Curiosity rover observations in Gale Crater
Physical properties of terrains encountered by the Curiosity rover during the first 360 sols of operations have been inferred from analysis of the scour zones produced by Sky Crane Landing System engine plumes, wheel touch down dynamics, pits produced by Chemical Camera (ChemCam) laser shots, rover wheel traverses over rocks, the extent of sinkage into soils, and the magnitude and sign of roverâbased slippage during drives. Results have been integrated with morphologic, mineralogic, and thermophysical properties derived from orbital data, and Curiosityâbased measurements, to understand the nature and origin of physical properties of traversed terrains. The hummocky plains (HP) landing site and traverse locations consist of moderately to wellâconsolidated bedrock of alluvial origin variably covered by slightly cohesive, hardâpacked basaltic sand and dust, with both embedded and surfaceâstrewn rock clasts. Rock clasts have been added through local bedrock weathering and impact ejecta emplacement and form a pavementâlike surface in which only small clasts (<5 to 10 cm wide) have been pressed into the soil during wheel passages. The bedded fractured (BF) unit, site of Curiosity's first drilling activity, exposes several alluvialâlacustrine bedrock units with little to no soil cover and varying degrees of lithification. Small wheel sinkage values (<1 cm) for both HP and BF surfaces demonstrate that compaction resistance countering drivenâwheel thrust has been minimal and that rover slippage while traversing across horizontal surfaces or going uphill, and skid going downhill, have been dominated by terrain tilts and wheelâsurface material shear modulus values
Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater
Opportunity has been traversing the Meridiani plains since 25 January 2004 (sol 1), acquiring numerous observations of the atmosphere, soils, and rocks. This paper provides an overview of key discoveries between sols 511 and 2300, complementing earlier papers covering results from the initial phases of the mission. Key new results include (1) atmospheric argon measurements that demonstrate the importance of atmospheric transport to and from the winter carbon dioxide polar ice caps; (2) observations showing that aeolian ripples covering the plains were generated by easterly winds during an epoch with enhanced Hadley cell circulation; (3) the discovery and characterization of cobbles and boulders that include iron and stonyâiron meteorites and Martian impact ejecta; (4) measurements of wall rock strata within Erebus and Victoria craters that provide compelling evidence of formation by aeolian sand deposition, with local reworking within ephemeral lakes; (5) determination that the stratigraphy exposed in the walls of Victoria and Endurance craters show an enrichment of chlorine and depletion of magnesium and sulfur with increasing depth. This result implies that regionalâscale aqueous alteration took place before formation of these craters. Most recently, Opportunity has been traversing toward the ancient Endeavour crater. Orbital data show that clay minerals are exposed on its rim. Hydrated sulfate minerals are exposed in plains rocks adjacent to the rim, unlike the surfaces of plains outcrops observed thus far by Opportunity. With continued mechanical health, Opportunity will reach terrains on and around Endeavour’s rim that will be markedly different from anything examined to date.Additional co-authors: RM Haberle, KE Herkenhoff, JA Herman, KD Iagnemma, BL Jolliff, JR Johnson, G Klingelhöfer, AH Knoll, AT Knudson, R Li, SM McLennan, DW Mittlefehldt, RV Morris, TJ Parker, MS Rice, LA Soderblom, SW Squyres, RJ Sullivan, MJ Wolf
X-ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest at Gale Crater
The Mars Science Laboratory rover Curiosity scooped samples of soil from the Rocknest aeolian
bedform in Gale crater. Analysis of the soil with the Chemistry and Mineralogy (CheMin) x-ray
diffraction (XRD) instrument revealed plagioclase (~An57), forsteritic olivine (~Fo62), augite,
and pigeonite, with minor K-feldspar, magnetite, quartz, anhydrite, hematite, and ilmenite.
The minor phases are present at, or near, detection limits. The soil also contains 27 ± 14 weight
percent x-ray amorphous material, likely containing multiple Fe^(3+)- and volatile-bearing phases,
including possibly a substance resembling hisingerite. The crystalline component is similar to
the normative mineralogy of certain basaltic rocks from Gusev crater on Mars and of martian
basaltic meteorites. The amorphous component is similar to that found on Earth in places
such as soils on the Mauna Kea volcano, Hawaii
Volatile and Organic Compositions of Sedimentary Rocks in Yellowknife Bay, Gale crater, Mars
HâO, COâ, SOâ, Oâ, Hâ, HâS, HCl, chlorinated hydrocarbons, NO and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. HâO/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the COâ. Concurrent evolution of Oâ and chlorinated hydrocarbons suggest the presence of oxychlorine phase(s). Sulfides are likely sources for S-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic C sources may be preserved in the mudstone; however, the C source for the chlorinated hydrocarbons is not definitively of martian origin
A Habitable Fluvio-Lacustrine Environment at Yellowknife Bay, Gale Crater, Mars
The Curiosity rover discovered fine-grained sedimentary rocks, inferred to represent an ancient lake, preserve evidence of an environment that would have been suited to support a Martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. C, H, O, S, N, and P were measured directly as key biogenic elements, and by inference N and P are assumed to have been available. The environment likely had a minimum duration of hundreds to tens of thousands of years. These results highlight the biological viability of fluvial-lacustrine environments in the post-Noachian history of Mars
The Petrochemistry of Jake_M: A Martian Mugearite
âJake_M,â the first rock analyzed by the Alpha Particle X-ray Spectrometer instrument on the
Curiosity rover, differs substantially in chemical composition from other known martian igneous
rocks: It is alkaline (>15% normative nepheline) and relatively fractionated. Jake_M is
compositionally similar to terrestrial mugearites, a rock type typically found at ocean islands and
continental rifts. By analogy with these comparable terrestrial rocks, Jake_M could have been
produced by extensive fractional crystallization of a primary alkaline or transitional magma at
elevated pressure, with or without elevated water contents. The discovery of Jake_M suggests that
alkaline magmas may be more abundant on Mars than on Earth and that Curiosity could encounter
even more fractionated alkaline rocks (for example, phonolites and trachytes)