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Surface Energy Budget, Albedo, and Thermal Inertia at Jezero Crater, Mars, as Observed From the Mars 2020 MEDA Instrument
No full textThe Mars Environmental Dynamics Analyzer (MEDA) on board Perseverance includes first-of-its-kind sensors measuring the incident and reflected solar flux, the downwelling atmospheric IR flux, and the upwelling IR flux emitted by the surface. We use these measurements for the first 350 sols of the Mars 2020 mission (Ls ∼ 6°–174° in Martian Year 36) to determine the surface radiative budget on Mars and to calculate the broadband albedo (0.3–3 μm) as a function of the illumination and viewing geometry. Together with MEDA measurements of ground temperature, we calculate the thermal inertia for homogeneous terrains without the need for numerical thermal models. We found that (a) the observed downwelling atmospheric IR flux is significantly lower than the model predictions. This is likely caused by the strong diurnal variation in aerosol opacity measured by MEDA, which is not accounted for by numerical models. (b) The albedo presents a marked non-Lambertian behavior, with lowest values near noon and highest values corresponding to low phase angles (i.e., Sun behind the observer). (c) Thermal inertia values ranged between 180 (sand dune) and 605 (bedrock-dominated material) SI units. (d) Averages of albedo and thermal inertia (spatial resolution of ∼3–4 m2) along Perseverance's traverse are in very good agreement with collocated retrievals of thermal inertia from Thermal Emission Imaging System (spatial resolution of 100 m per pixel) and of bolometric albedo in the 0.25–2.9 μm range from (spatial resolution of ∼300 km2). The results presented here are important to validate model predictions and provide ground-truth to orbital measurements
Parent body histories recorded in Rumuruti chondrite sulfides: Implications for the onset of oxidized, sulfur-rich core formation
No full textModels of planetary core formation beginning with melting of Fe,Ni metal and troilite are not readily applicable to oxidized and sulfur-rich chondrites containing only trace quantities of metal. Cores formed in these bodies must be dominated by sulfides. Siderophile trace elements used to model metallic core formation could be used to model oxidized, sulfide-dominated core formation and identify related meteorites if their trace element systematics can be quantified. Insufficient information exists regarding the behavior of these core-forming elements among sulfides during metamorphism prior to anatexis. Major, minor, and trace element concentrations of sulfides are reported in this study for petrologic type 3–6 R chondrite materials. Sulfide-dominated core-forming components in such oxidized chondrites (ƒO2 ≥ iron-wüstite) follow metamorphic evolutionary pathways that are distinct from reduced, metal-bearing counterparts. Most siderophile trace elements partition into pentlandite at approximately 10× chondritic abundances, but Pt, W, Mo, Ga, and Ge are depleted by 1–2 orders of magnitude relative to siderophile elements with similar volatilities. The distribution of siderophile elements is further altered during hydrothermal alteration as pyrrhotite oxidizes to form magnetite. Oxidized, sulfide-dominated core formation differs from metallic core formation models both physically and geochemically. Incongruent melting of pentlandite at 865°C generates melts capable of migrating along solid silicate grains, which can segregate to form a Ni,S-rich core at lower temperatures compared to reduced differentiated parent bodies and with distinct siderophile interelement proportions
40Ar/39Ar ages of L4, H5, EL6, and feldspathic ureilitic clasts from the Almahata Sitta polymict ureilite (asteroid 2008 TC3)
No full textThe Almahata Sitta (AhS) meteorite consists of disaggregated clasts from the impact of the polymict asteroid 2008 TC3, including ureilitic (70%–80%) and diverse non-ureilitic materials. We determined the 40Ar/39Ar release patterns for 16 AhS samples (3–1500 μg) taken from three chondritic clasts, AhS 100 (L4), AhS 25 (H5), and MS-D (EL6), as well as a clast of ureilitic trachyandesite MS-MU-011, also known as ALM-A, which is probably a sample of the crust of the ureilite parent body (UPB). Based on our analyses, best estimates of the 40Ar/39Ar ages (Ma) of the chondritic clasts are 4535 ± 10 (L4), 4537–4555 with a younger age preferred (H5), and 4513 ± 17 (EL6). The ages for the L4 and the H5 clasts are older than the most published 40Ar/39Ar ages for L4 and H5 meteorites, respectively. The age for the EL6 clast is typical of older EL6 chondrites. These ages indicate times of argon closure ranging up to 50 Ma after the main constituents of the host breccia, that is, the ureilitic components of AhS, reached the >800°C blocking temperatures of pyroxene and olivine thermometers. We suggest that these ages record the times at which the clasts cooled to the Ar closure temperatures on their respective parent bodies. This interpretation is consistent with the recent proposal that the majority of xenolithic materials in polymict ureilites were implanted into regolith 40–60 Ma after calcium–aluminum-rich inclusion and is consistent with the interpretation that 2008 TC3 was a polymict ureilite. With allowance for its 10-Ma uncertainty, the 4549-Ma 40Ar/39Ar age of ALM-A is consistent with closure within a few Ma of the time recorded by its Pb/Pb age either on the UPB or as part of a rapidly cooling fragment. Plots of age versus cumulative 39Ar release for 10 of 15 samples with ≥5 heating steps indicate minor losses of 40Ar over the last 4.5 Ga. The other five such samples lost some 40Ar at estimated times no earlier than 3800–4500 Ma bp. Clustering of ages in the low-temperature data for these five samples suggests that an impact caused localized heating of the AhS progenitor ~2.7 Ga ago. In agreement with the published work, 10 estimates of cosmic-ray exposure ages based on 38Ar concentrations average 17 ± 5 Ma but may include some early irradiation
Significance of Secondary Fe-Oxide and Fe-Sulfide Minerals in Upper Peak Ring Suevite from the Chicxulub Impact Structure
No full textThe suevite (polymict melt rock-bearing breccia) composing the upper peak ring of the Chicxulub impact crater is extremely heterogeneous, containing a combination of relict clasts and secondary minerals. Using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS) and electron probe microanalysis (EPMA), we investigated the nature and occurrence of primary and secondary Fe-oxide and Fe-sulfide minerals to better understand hydrothermal trends such as mineral precipitation and dissolution, and to document the remobilization of Fe and associated siderophile elements within suevites. Large primary Fe-oxides (~20–100 µm) reveal decomposition and dissolution patterns, forming sub-micrometer to micrometer Fe-oxide phases. Secondary sub-micrometer Fe-oxide crystals are also visibly concentrated within clay. The occurrence of Fe-oxide crystals within clay suggests that these likely formed at temperatures ≤100 °C, near the formation temperature of smectite. The formation of Fe-oxide minerals on clay surfaces is of interest as it may form a micro-setting, where free electrons (from the oxidation of Fe2+) and the adsorption of simple organic molecules on the surface of clay could generate reactive conditions favorable to microbial communities. Primary and secondary Fe-sulfide minerals exhibiting a variety of morphologies are present within samples, representing different formation mechanisms. Secondary Fe-sulfide minerals occur within rims of clasts and vesicles and in fractures and voids. Some secondary Fe-sulfide grains are associated with Ni- and Co-rich phases, potentially reflecting the post-impact migration of siderophile elements within the suevite of the Chicxulub crater
Science Objectives for Human Exploration of Mars Workshop report
No full textThe Science Objectives for Human Exploration of Mars Workshop was held in Denver, Colorado on May 4–6, 2022. The workshop was co-sponsored by NASA’s Science Mission Directorate and the Exploration Systems Development Mission Directorate to actively engage the planetary science community to determine what planetary science should be done by human crews on the martian surface and how those science objectives can be achieved.
Sessions at the Science Objectives for Human Exploration of Mars Workshop were organized around specific planetary science objectives and mission architecture concepts that were identified during the workshop as the highest priority for human exploration. The intent of this workshop was to synthesize a notional, integrated concept of operations for each scenario to aid in planning and refining the mission architecture for the first human mission to Mars. Results from the Planetary Decadal Survey Report were released xx days before the workshop and were briefed to workshop participants who incorporated the findings in the discussions.
With the Artemis missions, humans will return to the Moon using innovative technologies to explore the lunar surface. We will apply what we learn about exploration architecture, surface infrastructure, and science and exploration operations on and around the Moon to conduct successful missions with the first astronauts to Mars. A human mission to Mars will be a landmark achievement and a golden opportunity to make groundbreaking scientific discoveries on Mars. The potential scope of the science activities and impact of achieving those objectives are extraordinary.NASA’s Science Mission Directorate; NASA's Exploration Systems Development Mission DirectorateOrganizers: P. B. Niles; D.H. Needham; Sub-Team Leads: Archer, D. P.; Banfield, D. J.; Beaty, D.W.; Bell, M. S.; Curry, S. M.; Gangidine, A.; Hill, J.; Hoffman, S.; Horgan, B. H. Link, B. M.; Lynch, K; Matthies, L. H.; Mischna, M. A.; Rucker, M.; Stone, B
37th Summer Intern Conference (2022)
No full textPapers Presented at the 2022 Summer Intern Program for Undergraduates held at the Lunar and Planetary InstituteSponsored by Lunar and Planetary Institute, NASA Johnson Space CenterGeologic Mapping of Smooth Plains on Dione: Insights into Resurfacing Processes on Icy Bodies / D. A. Bickham and P. M. Schenk -- The Distribution and Volume of Impact Melt, Cleopatra Crater, Maxwell Montes, Venus / S. Bogart and A. H. Treiman -- A Mineralogic Investigation into the Onset of Core Formation in Highly Oxidized Asteroids /
D. L. Burgin, S. Crossley, and C. Goodrich -- Automating Size Determination of Near-Earth Asteroids Using Low SNR Arecibo Radar Imaging / C. E. Champagne, E. G. Rivera-Valentín, B. Aponte-Hernández, and P. A. Taylor -- Thermal Evolution of Enstatite Chondrite and Aubrite Parent Bodies / E. N. Etheridge, B. A. Anzures, N. Dygert, C. A. Goodrich, and F. M. McCubbin -- Analyses of Curiosity’s Ground Temperature Measurements: Correction for Thermal Noise / J. G. Gambrill and G. M. Martínez -- Investigating Source to Sink Processes on Earth to Connect to Mars / F. D. Garcia, C. C. Bedford, V. Tu, E. Rampe, and M. Thorpe -- Properties and Comparative Analysis of Venusian Rift Zones / T. E. McKenna, M. B. Weller, and W. S. Kiefer -- Diversity of Calcium-Aluminum-Rich Inclusions in CV, CK, and CL Chondrites / X. Mouti Al-Hashimi and P. Mane --The Role of Pluto’s Ocean’s Salinity in Supporting Nitrogen Ice Loads Within the Sputnik Planitia Basin / A. L. Nguyen and P. J. McGovern -- Multiple Tectonic and Volcanic Events: Gina Crater Area, Venus / E. R. Roberts, A. H. Treiman, G. L. Eggers, and J. Filiberto --
Investigation of Great Salt Lake Evaporite Spectra for Evidence of Mirabilite and Thenardite / W. L. Wallentine, K. Lynch, and G. Eggers -- Evaluating Boiling Curves and Their Implications for Impact-Generated Hydrothermal Systems on Mars / M. R. Westenberg, E. G. Rivera-Valentín, K. L. Lynch, and D. A. Kring -- Roughness Variations at Different Scales Within Irregular Mare Patches on the Moon / G. M. Wolff, J. D. Stopar, and E. G. Rivera-Valentín
Arecibo S-band radar characterization of local-scale heterogeneities within Mercury's north polar deposits
No full textGround-based planetary radar observations first revealed deposits of potentially nearly pure water ice in some permanently shadowed regions (PSRs) on Mercury's poles. Later, the MESSENGER spacecraft confirmed the icy nature of the deposits, as well as their location within PSRs. Considering the geologic context provided by MESSENGER, we further characterized the north polar deposits by pairing spacecraft data with new Arecibo S-band radar observations. Here we show that some ice deposits within PSRs have a gradational pattern in their radar properties that is likely associated with differences in ice purity.Edgard G. Rivera-Valentín, Heather M. Meyer, Patrick A. Taylor, Erwan Mazarico, Sriram S. Bhiravarasu, Anne K. Virkki, Michael C. Nolan, Nancy L. Chabot, and Jon D. Giorgin
The SHERLOC Calibration Target on the Mars 2020 Perseverance Rover: Design, Operations, Outreach, and Future Human Exploration Functions
No full textThe Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) is a robotic arm-mounted instrument onboard NASA’s Perseverance rover. SHERLOC combines imaging via two cameras with both Raman and fluorescence spectroscopy to investigate geological materials at the rover’s Jezero crater field site. SHERLOC requires in situ calibration to monitor the health and performance of the instrument. These calibration data are critically important to ensure the veracity of data interpretation, especially considering the extreme martian environmental conditions where the instrument operates. The SHERLOC Calibration Target (SCT) is located at the front of the rover and is exposed to the same atmospheric conditions as the instrument
SCM dataset for manuscript "Surface energy fluxes and temperatures at Jezero crater, Mars"
No full textA description of this dataset can be found in the file README.docxThis dataset contains the Single Column Model (SCM) output needed to reproduce and plot the results shown in Figs. 3-5, 7-11 and 13-14 of the manuscript entitled “Surface energy fluxes and temperatures at Jezero crater, Mars”, by H. I Savijärvi, G. M. Martinez, and A.-M. Harri, currently under review in JGR:Planets.Germán Martínez wants to acknowledge JPL funding from USRA Contract Number 163878
Low-Cost Science Mission Concepts (2022)
No full textEmerging small spacecraft capabilities and innovative new mission concepts offer opportunities for compelling science discoveries at Mars at unprecedented low costs. Here, "low-cost" equates to mission costs that fall well below the current Discovery Program cost cap. The recent Mars Architecture Strategy Working Group suggested that small spacecraft missions in the 300M cost range (including delivery) may offer a sweet spot in terms of achievable science per unit cost. Specific topics of interest for this workshop include: Assessment of strategic Mars science questions well-suited to investigation via low-cost, small spacecraft missions; Candidate low-cost mission concepts, relating science objectives to investigations, instruments, and spacecraft architecture; Small spacecraft capabilities for both orbital and landed Mars missions; Innovative mission design approaches, including piggyback, rideshare, and new small launch vehicle capabilities for low-cost delivery of payloads to Mars; New miniatured instruments, avionics, and subsystems enabling highly capable small spacecraft; Opportunities for international and commercial partnerships; Emerging commercial NewSpace capabilities that can be leveraged for low-cost Mars exploration.Science Organizing Committee: Shannon Curry (Co-Chair), University of California, Berkeley, Chad Edwards (Co-Chair), Jet Propulsion Laborator