Engineering topics

Johnson, J. R.

Publications and source records attributed to Johnson, J. R..

At least 19 records

DOE OSTI2024

Intense alteration on early Mars revealed by high-aluminum rocks at Jezero crater

The NASA Perseverance rover discovered light-toned float rocks scattered across the surface of Jezero crater that are particularly rich in alumina ( ~ 35 wt% Al 2 O 3 ) and depleted in other major elements (except silica). These unique float rocks have heterogeneous mineralogy ranging from kaolinite/halloysite-bearing in hydrated samples, to spinel-bearing in dehydrated samples also containing a dehydrated Al-rich phase. Here we describe SuperCam and Mastcam-Z observations of the float rocks, including the first in situ identification of kaolinite or halloysite on another planet, and dehydrated phases including spinel and apparent partially dehydroxylated kaolinite. The presence of spinel in these samples is likely detrital in origin, surviving kaolinitization, pointing to an ultramafic origin. However, the association of low hydration with increased Al 2 O 3 abundances suggests heating-induced dehydration which could have occurred during the lithification or impact excavation of these rocks. Given the orbital context of kaolinite-bearing megabreccia in the Jezero crater rim, we propose an origin for these rocks involving intense aqueous alteration of the parent material, followed by dehydration/lithification potentially through impact processes, and dispersion into Jezero crater through flood or impact-related processes.

58 GEOSCIENCES↗

NASA NTRS2020

First Gale Western Butte Capping-Unit Compositions, and Relationships to Earlier Units Along Curiosity's Traverse

The Curiosity rover has been traversing through the clay-bearing unit (Glen Torridon; GT), approaching Greenheugh pediment, a large, fan-shaped surface surrounding the mouth of Gediz Vallis on the lower slope of Mt. Sharp. The pediment unconformably overlies the underlying bedrock, and is hence younger than units of the Mt. Sharp group. Orbital imaging of the pediment has shown it to have a slightly lower albedo and higher thermal inertia than neighboring units, to be relatively retentive of craters (e.g., erosion resistant), and to exhibit curved bedforms suggestive of lithified eolian bedforms. No diagnostic spectral signature has been observed from orbit. Recent rover positions allowed remote imaging of the contact between Greenheugh pediment and the eroded Murray formation strata below it, showing that the pediment capping material is cross-bedded and relatively thin (1-3 m), and suggesting that the pediment may have been much larger at one time. As Curiosity approached the edge of the pediment, the team investigated two buttes named Central and Western. The latter butte contains dark capping material that initially looked similar to the pediment cap, but close inspection revealed important physical differences. Here we report on compositions from ChemCam of two float rocks that appear to have rolled down from the capping unit, and on potential relation-ships to other targets along the traverse of the rover.

Wiens, R. C.↗

NASA NTRS2019

Variations in Visible/Near-Infrared Hematite Spectra Related to Grain Size and Crystallinity

Drill fines created by the Curiosity rover at Gale Crater, Mars have exhibited variable visible/near-infrared spectral features attributable to the presence of ferrous and ferric minerals. Drilled locations within the Murray formation and on the Vera Rubin Ridge (VRR) were shown by the CheMin instrument to contain significant amounts of hematite. However, typical hematite spectral features (e.g., absorptions near 530 nm and 860 nm) have varied inconsistently with hematite abundances. This suggests that other factors such as hematite grain size or crystallinity, the presence of amorphous materials, and/or photometric effects play a role in the observed spectra. Using laboratory spectra of hematite acquired at difference grain sizes, we document the variability in key spectral features. We also compare spectral parameters computed from Mastcam spectra on Mars of three hematite-bearing ChemCam calibration target (CCCT) samples with known hematite and amorphous material abundances.

Johnson, J. R.↗

NASA NTRS2019

Rock Hard Science: Multispectral and Mineralogical Investigations to Understand Bedrock Spectral Properties and Strength at Vera Rubin Ridge, Gale Crater, Mars

Since the beginning of the Mars Science Laboratory (MSL) mission, Vera Rubin Ridge (VRR) has been a location of interest to the MSL science team because of its apparent erosional resistance and strong near-IR (~860 nm) absorption feature seen from orbit in the Mars Reconnaissance Orbiter mission's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data. The strong CRISM absorption feature along VRR was hypothesized to be primarily associated with an increased abundance of crystal-line hematite compared to lower Mt. Sharp units. How-ever, surface multispectral and mineralogic data, from the Mastcam and CheMin instruments onboard the Curiosity rover, suggest hematite is not the only mineral contributing to the near-IR absorption feature measured in VRR or the reason for its relative hardness.

Jacob, S. R.↗

NASA NTRS2018

Curiosity's Investigation at Vera Rubin Ridge

The Curiosity rover is exploring Vera Rubin Ridge (VRR), a ~6.5 km long and ~200 m wide topographic feature trending northeast-southwest across Aeolis Mons (informally known as Mt. Sharp) (Fig 1). In orbital data, VRR is distinct from the underlying Murray formation due to its relative erosional resistance and greater exposure of bedrock. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) orbital data show a hematite spectral signature over much of the ridge (Fig. 2). On the ground, Curiosity also observed hematite associated with the sedimentary rocks of the underlying Murray formation, although these detections are difficult to see with CRISM due to mixing with sand and dust.

Fraeman, A. A.↗

NASA NTRS2018

ChemCam Investigation of the Last Four MSL Drill Sites in the Murray Formation, Gale Crater, Mars

This study utilizes ChemCam data for outcrop surfaces, drill hole walls, tailings, and dump piles in the Middle Murray Formation to investigate chemical variations with depth in the drill holes and pos-sible effects of the drilling and sample processing. This work is a continuation of similar work on drill sites at Yellowknife Bay [1], the Pahrump Hills [2], and the Stimson Formation [3].

Jackson, R. S.↗

NASA NTRS2017

Pancam Multispectral and APXS Chemical Examination of Rocks and Soils in Marathon Valley and Points South Along the Rim of Endeavour Crater

The Mars Exploration Rover Opportunity has concluded its exploration of Marathon Valley, a 100-meter-wide valley in the western rim of the 22-kilometer-diameter Endeavour crater. Orbital observations from CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) indicated the presence of Fe smectites in Marathon Valley. Since leaving the valley, Opportunity has been traversing along the inner rim of the crater, and currently towards the outer rim. This presentation describes the Pancam 430 to 1009 nanometer (VNIR - Visible and Near Infared) multispectral reflectance and APXS (Alpha Particle X-ray Spectrometer) chemical compositions of rock and soil units observed during the latter portions of the Marathon Valley campaign on the Knudson Ridge area and observations of those materi-als along the traverse to the south. Full Pancam spectral coverage of rock targets consists of 13 filter (13f) data collections with 11 spectrally unique channels with data processing. Data were examined using spectral parameters, decorrelation stretch composites, and spectral mixture analysis. Note that color terms used here refer to colors in various false-color renditions, not true colors. The APXS determines major and select trace element compositions of targets.

Farrand, W. H.↗

NASA NTRS2016

VNIR Multispectral Observations of Rocks at Spirit of St. Louis Crater and Marathon Valley on Th Rim of Endeavour Crater Made by the Opportunity Rover Pancam

The Mars Exploration Rover Opportunity has been exploring the western rim of the 22 km diameter Endeavour crater since August, 2011. Recently, Opportunity has reached a break in the Endeavour rim that the rover team has named Mara-thon Valley. This is the site where orbital observations from the MRO CRISM imaging spectrometer indicated the presence of iron smectites. On the outer western portion of Marathon Valley, Opportunity explored the crater-form feature dubbed Spirit of St. Louis (SoSL) crater. This presentation describes the 430 to 1009 nm (VNIR) reflectance, measured by the rover's Pancam, of rock units present both at Spirit of St. Louis and within Marathon Valley.

Farrand, W. H.↗

NASA NTRS2015

Multispectral Evidence of Alteration from Murray Ridge to Marathon Valley Observed by the Opportunity Pancam on the Rim of Endeavour Crater, Mars

The Mars Exploration Rover Opportunity has been traversing the rim of the Noachian‐aged, 22 km diameter Endeavour crater. Circa sol 3390 of its mission, Opportunity reached the northern tip of the rim segment known as Solander Point and has since been traversing the rim to the south to its current location at the break in the rim known as Marathon Valley. The rocks making up the rim are dominated by impact breccias consisting of clasts and a finer‐grained matrix. Several segments of the rim are transected by fractures as observed from orbital HiRISE imagery. Pancam multispectral observations of outcrop in these fracture regions, including part of the rim crest dubbed Murray Ridge, the Hueytown fracture, and Marathon Valley have been made. Over the range of 430 to 1010 nm there are changes in the multispectral reflectance signature of the breccia matrix with an increase in 535 nm and 904 nm band depth. This is attributed to oxidation and an increase in ferric oxides in these areas. In situ observations by the rover's APXS also indicate chemical differences associated with the matrix along these fractures, including increasing Fe/Mn southward from Solander Point to a region having an Al‐OH signature in CRISM spectra, and generally higher SO3 in the Hueytown fracture region and the area around Spirit of St. Louis. Overturned rocks observed on Murray Ridge were determined by the APXS to have elevated Mn and Pancam spectra of the high Mn spots have a characteristic red, featureless slope. This spectrum was also observed in association with some coatings on blocks of the sulfate‐rich Grasberg formation. Spectra resembling red hematite are observed in some zones in association with the craterform feature Spirit of St. Louis outside the mouth (to the west) of Marathon Valley. Marathon Valley itself has been observed from orbital hyperspectral observations by the CRISM sensor to host occurrences of Fe/Mg smectite minerals‐ indicating extensive aqueous alteration in this region. Pancam observations in Marathon Valley will play an important role in surveying outcrop and making VNIR spectral comparisons with clay bearing outcrop examined earlier in the mission at the Matijevic Hill region.

Farrand, W. H.↗

NASA NTRS2014

Calcium Sulfate Characterized by ChemCam/Curiosity at Gale Crater, Mars

Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of :(1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of the targets [1;2] and (2) a Remote Micro Imager (RMI), for the imaging context of laser analysis [3]. Within the Gale crater, Curiosity traveled from Bradbury Landing through the Rocknest region and into Yellowknife Bay (YB). In the latter, abundant light-toned fracture-fill material were seen [4;5]. ChemCam analysis demonstrate that those fracture fills consist of calcium sulfates [6].

Nachon, M.↗

NASA NTRS2014

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 rst 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 rover-based slippage during drives. Results have been integrated with morphologic, mineralogic, and thermophysical properties derived from orbital data, and Curiosity-based measurements, to understand the nature and origin of physical properties of traversed terrains. The hummocky plains (HP) landing site and traverse locations consist ofmoderately to well-consolidated bedrock of alluvial origin variably covered by slightly cohesive, hard-packedbasaltic sand and dust, with both embedded and surface-strewn rock clasts. Rock clasts have been addedthrough local bedrock weathering and impact ejecta emplacement and form a pavement-like surface in whichonly small clasts (5 to 10 cm wide) have been pressed into the soil during wheel passages. The beddedfractured (BF) unit, site of Curiositys rst drilling activity, exposes several alluvial-lacustrine bedrock unitswith little to no soil cover and varying degrees of lithication. Small wheel sinkage values (1 cm) for both HPand BF surfaces demonstrate that compaction resistance countering driven-wheel thrust has been minimaland that rover slippage while traversing across horizontal surfaces or going uphill, and skid going downhill,have been dominated by terrain tilts and wheel-surface material shear modulus values.

Mars Science Laboratory Curiosity Gale Crater↗

NASA NTRS2009

Santorini, Another Meteorite on Mars and Third of a Kind

The Mars Exploration Rover (MER) Opportunity has been studying Meridiani Planum for five years. On sol 1634 of its mission, Opportunity left Victoria crater after investigating it for approximately 682 sols [1] and is now on a journey towards Endeavour, a 24 km diameter crater about 12 km southeast of Victoria. A priority along the way is the investigation of cobbles, which in the jargon of the MER science team denotes any loose rock fragment larger than a couple of centimeters. Cobbles investigated thus far are of diverse origin [2] and provide the only means to investigate material other than the ubiquitous sulfate-rich outcrop, basaltic sand or hematiterich spherules dubbed blueberries. Some of these cobbles are meteorites [3]. Meteorites on Mars are not just a curiosity that make Mars a more Earth-like planet. Metallic iron in meteorites, for example, may be used as a more sensitive tracer for volatile surface interactions compared to igneous minerals [4]. Between sols 1713 and 1749, including the period of Mars solar conjunction, Opportunity investigated a cobble informally named Santorini. Its chemical and mineralogical composition is very similar to Barberton and Santa Catarina, two cobbles that were identified as meteorites and which are probably related to each other [3]. Santorini was investigated with the rover s Panoramic Camera (Pancam), Microscopic Imager (MI), Alpha-Particle X-ray Spectrometer (APXS) and Moessbauer (MB) spectrometer. The miniature Thermal Emission Spectrometer (mini-TES) was not operational at the time. The Rock Abrasion Tool (RAT) could not be used to brush off potential dust coatings because of unfavorable geometry.

Schroeder, C.↗

NASA NTRS2007

Pyroclastic Activity at Home Plate in Gusev Crater, Mars

Home Plate is a layered plateau in Gusev crater on Mars. It is composed of clastic rocks of moderately altered alkali basalt composition, enriched in some highly volatile elements. A coarse-grained lower unit is overlain by a finer-grained upper unit. Textural observations indicate that the lower strata were emplaced in an explosive event, and geochemical considerations favor an explosive volcanic origin over an impact origin. The lower unit likely represents accumulation of pyroclastic materials, while the upper unit may represent eolian reworking of the same pyroclastic materials.

Squyres, S. W.↗

NASA NTRS2007

Mars Exploration Rover Pancam Multispectral Imaging of Rocks, Soils, and Dust at Gusev Crater and Meridiani Planum

Multispectral imaging from the Panoramic Camera (Pancam) instruments on the Mars Exploration Rovers Spirit and Opportunity has provided important new insights about the geology and geologic history of the rover landing sites and traverse locations in Gusev crater and Meridiani Planum. Pancam observations from near-UV to near-IR wavelengths provide limited compositional and mineralogic constraints on the presence abundance, and physical properties of ferric- and ferrous-iron bearing minerals in rocks, soils, and dust at both sites. High resolution and stereo morphologic observations have also helped to infer some aspects of the composition of these materials at both sites. Perhaps most importantly, Pancam observations were often efficiently and effectively used to discover and select the relatively small number of places where in situ measurements were performed by the rover instruments, thus supporting and enabling the much more quantitative mineralogic discoveries made using elemental chemistry and mineralogy data. This chapter summarizes the major compositionally- and mineralogically-relevant results at Gusev and Meridiani derived from Pancam observations. Classes of materials encountered in Gusev crater include outcrop rocks, float rocks, cobbles, clasts, soils, dust, rock grindings, rock coatings, windblown drift deposits, and exhumed whitish/yellowish salty soils. Materials studied in Meridiani Planum include sedimentary outcrop rocks, rock rinds, fracture fills, hematite spherules, cobbles, rock fragments, meteorites, soils, and windblown drift deposits. This chapter also previews the results of a number of coordinated observations between Pancam and other rover-based and Mars-orbital instruments that were designed to provide complementary new information and constraints on the mineralogy and physical properties of martian surface materials.

Bell, J. F., III↗

NASA NTRS2006

Evidence for Halite at Meridiani Planum

The outcrop rocks investigated by the Mars Exploration Rover (MER) Opportunity at Meridiani Planum consist of altered basaltic fines emplaced through aeolian and aqueous processes. Diagenesis through episodes of groundwater influx is likely responsible for lithification of the sediments, formation and subsequent dissolution of embedded crystals, and development of hematitic spherules with occasional cemented overgrowths [1]. The action of liquid water in the development of these rocks prompts the search for pure evaporative salts such as chlorides. Extensive deposits of this nature have not yet been discovered and may be a result of erosion and removal from stratigraphic layers above those sampled by Opportunity, or burial beneath accessible depths [2]. Nonetheless, the presence of small amounts of halite (NaCl) associated with coatings and rinds is indicated by the available data.

Yen, Albert S.↗

NASA NTRS2006

Spectral Variability among Rocks in Visible and Near Infrared Multispectral Pancam Data Collected at Gusev Crater: Examinations using Spectral Mixture Analysis and Related Techniques

Visible and Near Infrared (VNIR) multispectral observations of rocks made by the Mars Exploration Rover Spirit s Panoramic camera (Pancam) have been analysed using a spectral mixture analysis (SMA) methodology. Scenes have been examined from the Gusev crater plains into the Columbia Hills. Most scenes on the plains and in the Columbia Hills could be modeled as three endmember mixtures of a bright material, rock, and shade. Scenes of rocks disturbed by the rover s Rock Abrasion Tool (RAT) required additional endmembers. In the Columbia Hills there were a number of scenes in which additional rock endmembers were required. The SMA methodology identified relatively dust-free areas on undisturbed rock surfaces, as well as spectrally unique areas on RAT abraded rocks. Spectral parameters from these areas were examined and six spectral classes were identified. These classes are named after a type rock or area and are: Adirondack, Lower West Spur, Clovis, Wishstone, Peace, and Watchtower. These classes are discriminable based, primarily, on near-infrared (NIR) spectral parameters. Clovis and Watchtower class rocks appear more oxidized than Wishstone class rocks and Adirondack basalts based on their having higher 535 nm band depths. Comparison of the spectral parameters of these Gusev crater rocks to parameters of glass-dominated basaltic tuffs indicates correspondence between measurements of Clovis and Watchtower classes, but divergence for the Wishstone class rocks which appear to have a higher fraction of crystalline ferrous iron bearing phases. Despite a high sulfur content, the rock Peace has NIR properties resembling plains basalts.

Farrand, W. H.↗

NASA NTRS2005

Large Multispectral and Albedo Panoramas Acquired by the Pancam Instruments on the Mars Exploration Rovers Spirit and Opportunity

Introduction. The panoramic camera (Pancam) multispectral, stereoscopic imaging systems on the Mars Exploration Rovers Spirit and Opportunity [1] have acquired and downlinked more than 45,000 images (~35 Gbits of data) over more than 700 combined sols of operation on Mars as of early January 2005. A large subset of these images were acquired as part of 26 large multispectral and/or broadband "albedo" panoramas (15 on Spirit, 11 on Opportunity) covering large ranges of azimuth (12 spanning 360 ) and designed to characterize major regional color and albedo characteristics of the landing sites and various points along both rover traverses.

Bell, J. F., III↗

NASA NTRS2005

Unified Planetary Coordinates System: A Searchable Database of Geodetic Information

Over the past 40 years, an enormous quantity of orbital remote sensing data has been collected for Mars from many missions and instruments. Unfortunately these datasets currently exist in a wide range of disparate coordinate systems, making it extremely difficult for the scientific community to easily correlate, combine, and compare data from different Mars missions and instruments. As part of our work for the PDS Imaging Node and on behalf of the USGS Astrogeology Team, we are working to solve this problem and to provide the NASA scientific research community with easy access to Mars orbital data in a unified, consistent coordinate system along with a wide variety of other key geometric variables. The Unified Planetary Coordinates (UPC) system is comprised of two main elements: (1) a database containing Mars orbital remote sensing data computed using a uniform coordinate system, and (2) a process by which continual maintainance and updates to the contents of the database are performed.

Becker, K. J.a↗