Investigating Triboelectric Discharge at Gale Crater, Mars

Saltation-induced triboelectric discharge has been theorized to occur on Mars, how- ever, it has never been observed in-situ. It is hypothesized to play a key role in trace gas variation at Gale Crater, specifically as a fast destruction mechanism for methane. To maximize the likelihood of observing the discharges faint signal, a high- resolution record of saltation activity was produced using MastCam-100. MastCam-L0 and MAHLI were found to be the most suitable cameras with which to observe the discharge. Since the magnitude of discharge is well below the dark noise of these two cameras, it will not be possible to see the glow. However, performing such an ob- servation will enable the definition of an upper limit of the magnitude of discharge, calculated in this work as the radiance limit of the respective cameras. Comparing the annual methane and saltation cycles shows methane levels decreasing in conjunction with increase in saltation activity

Detecting Life on Mars

The objective of NASA JPL's latest mission, the Mars 2020 Rover, is to detect extinct life on Mars and to cache samples for a future Mars sample return mission. SHERLOC, an instrument on the arm of the rover, accomplishes the former byidentifying organic compounds using Deep UV Fluorescence and Raman Spectrometry. SHERLOC is designed to search for in situ organics. However, given that such biomolecules exist to be found, will SHERLOC be able to detect them? What is its detection limit? What sort of resolution will the Raman spectrum obtain? Is there a danger of false positive or irregular Raman detection? To investigate these questions, I created biological samples mixed with Martian soil simulant, sealed in Martian gas and subjected to long term heating to mimic the characteristics of organic biomarkers that SHERLOC might find on Mars. I then performed spectrometry on these samples at NASA JPL to reveal possible fluorescence and Raman maps SHERLOC would produce on Mars with compositionally similar soil. The samples were degenerated significantly with high temperature and low pressure to mimic the billion year long diagenesis on the Martian surface and to test the limits of detection of the instrument. The spectral analyses of these lab samples can then be used as a standard to confirm organic biomarkers on Mars. The compounds identified by the instrument were cross-checked with DNA extraction, X-Ray diffraction, and High Performance Liquid Chromatography to assess its accuracy and sensitivity. In Week 0 of the experiment, SHERLOC was able to detect a partial number of the organic compounds present in the experimental samples, such as, phosphate ion, amino acids, C-C, benzene ring, C=C, C-H, and aromatic hydrocarbons. The spectral signal weakened significantly in Week 2 with C-H and phosphate ion bonds no longer detected. No peaks were present by Week 4. No false positives, irregular raman spectra or DNA were detected by SHERLOC. No DNA could be extracted in the lab samples after Week 0. There was a steady racemization of aspartic acid over the duration of the experiment, with the D/L ratios increasing from 0 to 0.8. The detection limit of the instrument based on correlating aspartic acid concentration and absence of Raman peaks was found to be 0.144 ppm

Day-night differences in Mars methane suggest nighttime containment at Gale crater

We report new measurements of atmospheric methane by the Curiosity rover’s Tunable Laser Spectrometer that is part of the Sample Analysis at Mars suite (TLS-SAM), finding nondetections during two daytime measurements of average value 0.05 ± 0.22 ppbv (95% confidence interval CI). These are in marked contrast with nighttime background levels of 0.52 ± 0.10 (95% CI) from four measurements taken during the same season of northern summer. This large day-night difference suggests that methane accumulates while contained near the surface at night, but drops below TLS-SAM detection limits during the day, consistent with the daytime nondetection by instruments on board the ExoMars Trace Gas Orbiter. With no evidence for methane production by the rover itself, we propose that the source is one of planetary micro-seepage. Dynamical modeling indicates that such methane release is contained within the collapsed planetary boundary layer (PBL) at night due to a combination of nocturnal inversion and convergent downslope flow winds that confine the methane inside the crater close to the point where it is released. The methane abundance is then diluted during the day through increased vertical mixing associated with a higher altitude PBL and divergent upslope flow that advects methane out of the crater region. We also report detection of a large spike of methane in June 2019 with a mean in situ value over a two-hour ingest of 20.5 ± 4 ppbv (95% CI). If near-surface production is occurring widely across Mars, it must be accompanied by a fast methane destruction or sequestration mechanism, or both

CONSTRUCTING GEOLOGICAL CROSS-SECTIONS TO CONSTRAIN THE THREE-DIMENSIONAL STRATIGRAPHIC ARCHITECTURE OF THE JEZERO DELTA FRONT

International audienceThe NASA Mars2020 rover Perseverance has been traversing series that represent the transition from crater floor lithologies to deposits of the Jezero western delta since Sol 422 of rover operations [1]. During that time, the mission has explored the exposed stratigraphic succession at the delta front, named the Shenandoah formation [2]. Here we analyse Mastcam-Z mosaics and 3D data products derived from Planetary Robotics processing and viewing tools (PRoViP and PRo3D [3]) to map the 3D geometry of key stratigraphic boundaries and document the 3D stratigraphic architecture at the sub-km- to m-scale within the Shenandoah formation

CONSTRUCTING GEOLOGICAL CROSS-SECTIONS TO CONSTRAIN THE THREE-DIMENSIONAL STRATIGRAPHIC ARCHITECTURE OF THE JEZERO DELTA FRONT

International audienceThe NASA Mars2020 rover Perseverance has been traversing series that represent the transition from crater floor lithologies to deposits of the Jezero western delta since Sol 422 of rover operations [1]. During that time, the mission has explored the exposed stratigraphic succession at the delta front, named the Shenandoah formation [2]. Here we analyse Mastcam-Z mosaics and 3D data products derived from Planetary Robotics processing and viewing tools (PRoViP and PRo3D [3]) to map the 3D geometry of key stratigraphic boundaries and document the 3D stratigraphic architecture at the sub-km- to m-scale within the Shenandoah formation

SEDIMENTOLOGY AND STRATIGRAPHY OF THE LOWER DELTA SEQUENCE, JEZERO CRATER,MARS

International audienceIn April 2022, the Mars 2020 Perseverance rover arrived at the base of the ancient delta in Jezero crater after completing the first year of its mission exploring and sampling aqueously altered igneous rocks of the present-day crater floor [1]. Perseverance then spent ~200 sols exploring the lower ~25 m of rock exposed within the eastern scarp of the Jezero delta [2], a sedimentary sequence informally named the ‘Shenandoah’ formation. This studydescribes the sedimentology and stratigraphy of the Shenandoah formation explored by Perseverance at two sections—'Cape Nukshak’ and ‘Hawksbill Gap’— including a description, interpretation, and depositional framework for the facies that comprise it

SEDIMENTOLOGY AND STRATIGRAPHY OF THE LOWER DELTA SEQUENCE, JEZERO CRATER,MARS

International audienceIn April 2022, the Mars 2020 Perseverance rover arrived at the base of the ancient delta in Jezero crater after completing the first year of its mission exploring and sampling aqueously altered igneous rocks of the present-day crater floor [1]. Perseverance then spent ~200 sols exploring the lower ~25 m of rock exposed within the eastern scarp of the Jezero delta [2], a sedimentary sequence informally named the ‘Shenandoah’ formation. This studydescribes the sedimentology and stratigraphy of the Shenandoah formation explored by Perseverance at two sections—'Cape Nukshak’ and ‘Hawksbill Gap’— including a description, interpretation, and depositional framework for the facies that comprise it

Future of the Search for Life: Workshop Report

International audienceThe 2-week, virtual Future of the Search for Life science and engineering workshop brought together more than 100 scientists, engineers, and technologists in March and April 2022 to provide their expert opinion on the interconnections between life-detection science and technology. Participants identified the advances in measurement and sampling technologies they believed to be necessary to perform in situ searches for life elsewhere in our Solar System, 20 years or more in the future. Among suggested measurements for these searches, those pertaining to three potential indicators of life termed “dynamic disequilibrium,” “catalysis,” and “informational polymers” were identified as particularly promising avenues for further exploration. For these three indicators, small breakout groups of participants identified measurement needs and knowledge gaps, along with corresponding constraints on sample handling (acquisition and processing) approaches for a variety of environments on Enceladus, Europa, Mars, and Titan. Despite the diversity of these environments, sample processing approaches all tend to be more complex than those that have been implemented on missions or envisioned for mission concepts to date. The approaches considered by workshop breakout groups progress from nondestructive to destructive measurement techniques, and most involve the need for fluid (especially liquid) sample processing. Sample processing needs were identified as technology gaps. These gaps include technology and associated sampling strategies that allow the preservation of the thermal, mechanical, and chemical integrity of the samples upon acquisition; and to optimize the sample information obtained by operating suites of instruments on common samples. Crucially, the interplay between science-driven life-detection strategies and their technological implementation highlights the need for an unprecedented level of payload integration and extensive collaboration between scientists and engineers, starting from concept formulation through mission deployment of life-detection instruments and sample processing systems

Physical Sedimentology and Stratigraphy of the lower Western Fan (Shenandoah formation) Jezero Crater, Mars:: Results from the Mars 2020 “Delta Front” Campaign

International audienceThe Perseverance rover is exploring a sedimentary deposit within the Late Noachian-aged (4.0-4.8 Ga) Jezero Crater interpreted to be the remnants of a delta. From April 2022 through February 2023, Perseverance investigated the basal 25 m of sediments exposed in the fan’s eastern scarp. Rover instruments collected a suite of imaging, geochemical, mineralogical, and ground-penetrating radar data.Perseverance made detailed observations through two sections of the lower fan ~600 m apart. Similar facies and stratigraphic trends are present in both sections. Each section contains two coarsening-up successions. While some finer-grained units are laterally continuous between the two sections, the coarser-grained bodies that cap each section are laterally discontinuous and do not extend between sections.Both sequences are 10 - 15 m thick. Their lower strata are dominated by sulfate-cemented, planar laminated, very fine- to medium-grained sandstone and siltstone with rare low-angle truncations. Soft-sediment deformation occurs in the form of decimeter-scale lateral folds. Laminae are normally graded. These sequences are capped by meter-scale thick sheets of coarse-grained sandstone, pebbly sandstones, and conglomerates that are variably low-angle cross-bedded, trough cross-bedded, and planar-stratified. Plane beds are massive or normally graded.Two hypotheses for the depositional environment have emerged for this succession: a sub-aerial setting with extensive “overbank” facies and shallow braided channels and a proximal pro-deltaic setting with deposition driven by hyperpycnal flows. These hypotheses will be tested against observations made by Perseverance as it traverses the “Fan Top” and by more comprehensive studies of the “Delta Front” data

Physical Sedimentology and Stratigraphy of the lower Western Fan (Shenandoah formation) Jezero Crater, Mars:: Results from the Mars 2020 “Delta Front” Campaign

International audienceThe Perseverance rover is exploring a sedimentary deposit within the Late Noachian-aged (4.0-4.8 Ga) Jezero Crater interpreted to be the remnants of a delta. From April 2022 through February 2023, Perseverance investigated the basal 25 m of sediments exposed in the fan’s eastern scarp. Rover instruments collected a suite of imaging, geochemical, mineralogical, and ground-penetrating radar data.Perseverance made detailed observations through two sections of the lower fan ~600 m apart. Similar facies and stratigraphic trends are present in both sections. Each section contains two coarsening-up successions. While some finer-grained units are laterally continuous between the two sections, the coarser-grained bodies that cap each section are laterally discontinuous and do not extend between sections.Both sequences are 10 - 15 m thick. Their lower strata are dominated by sulfate-cemented, planar laminated, very fine- to medium-grained sandstone and siltstone with rare low-angle truncations. Soft-sediment deformation occurs in the form of decimeter-scale lateral folds. Laminae are normally graded. These sequences are capped by meter-scale thick sheets of coarse-grained sandstone, pebbly sandstones, and conglomerates that are variably low-angle cross-bedded, trough cross-bedded, and planar-stratified. Plane beds are massive or normally graded.Two hypotheses for the depositional environment have emerged for this succession: a sub-aerial setting with extensive “overbank” facies and shallow braided channels and a proximal pro-deltaic setting with deposition driven by hyperpycnal flows. These hypotheses will be tested against observations made by Perseverance as it traverses the “Fan Top” and by more comprehensive studies of the “Delta Front” data