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Recent robotic missions to Mars have offered new insights into the extent, diversity and habitability of the Martian sedimentary rock record. Since the Curiosity rover landed in Gale crater in August 2012, the Mars Science Laboratory Science Team has explored the origins and habitability of ancient fluvial, deltaic, lacustrine and aeolian deposits preserved within the crater. This study describes the sedimentology of a ca 13 m thick succession named the Pahrump Hills member of the Murray formation, the first thick fine‐grained deposit discovered in situ on Mars. This work evaluates the depositional processes responsible for its formation and reconstructs its palaeoenvironmental setting. The Pahrump Hills succession can be sub‐divided into four distinct sedimentary facies: (i) thinly laminated mudstone; (ii) low‐angle cross‐stratified mudstone; (iii) cross‐stratified sandstone; and (iv) thickly laminated mudstone–sandstone. The very fine grain size of the mudstone facies and abundant millimetre‐scale and sub‐millimetre‐scale laminations exhibiting quasi‐uniform thickness throughout the Pahrump Hills succession are most consistent with lacustrine deposition. Low‐angle geometric discordances in the mudstone facies are interpreted as 'scour and drape' structures and suggest the action of currents, such as those associated with hyperpycnal river‐generated plumes plunging into a lake. Observation of an overall upward coarsening in grain size and thickening of laminae throughout the Pahrump Hills succession is consistent with deposition from basinward progradation of a fluvial‐deltaic system derived from the northern crater rim into the Gale crater lake. Palaeohydraulic modelling constrains the salinity of the ancient lake in Gale crater: assuming river sediment concentrations typical of floods on Earth, plunging river plumes and sedimentary structures like those observed at Pahrump Hills would have required lake densities near freshwater to form. The depositional model for the Pahrump Hills member presented here implies the presence of an ancient sustained, habitable freshwater lake in Gale crater for at least ca 103 to 107 Earth years. [ABSTRACT FROM AUTHOR]

The Mars Hand Lens Imager (MAHLI) is a 2-megapixel, color camera with resolution as high as 13.9 µm pixel−1 . MAHLI has operated successfully on the Martian surface for over 1150 Martian days (sols) aboard the Mars Science Laboratory (MSL) rover, Curiosity. During that time MAHLI acquired images to support science and science-enabling activities, including rock and outcrop textural analysis; sand characterization to further the understanding of global sand properties and processes; support of other instrument observations; sample extraction site documentation; range-finding for arm and instrument placement; rover hardware and instrument monitoring and safety; terrain assessment; landscape geomorphology; and support of rover robotic arm commissioning. Operation of the instrument has demonstrated that imaging fully illuminated, dust-free targets yields the best results, with complementary information obtained from shadowed images. The light-emitting diodes (LEDs) allow satisfactory night imaging but do not improve daytime shadowed imaging. MAHLI’s combination of finescale, science-driven resolution, RGB color, the ability to focus over a large range of distances, and relatively large field of view (FOV), have maximized the return of science and science-enabling observations given the MSL mission architecture and constraints. [ABSTRACT FROM AUTHOR]

The pre-mission Apollo 15, 16, and 17 geologic maps have not been updated in approximately forty years, and the availability of recently acquired high-resolution images, multispectral data, and detailed topography and gravity data, when coupled with the Apollo field observations and decades of sample analyses, makes this a prime opportunity to do so. These areas were selected because they are more geologically diverse, the missions covered greater traverse distances, and there were additional science investigations associated with them. This investigation will produce 6 new USGS Special Investigation Maps at the regional (1:200,000) and landing site (1:24,000) scales to take advantage of the higher resolution of the Lunar Reconnaissance Orbiter Wide Angle Camera and Narrow Angle Camera base maps. Concurrent with the mapping efforts led by the project team, we collected measurements of craters ≥500 m on the 1:200,000 maps and ≥10 m on the 1:24,000 maps for all six map areas using the CraterTools extension, excluding secondaries and the areas containing them. To date, we have mapped ~640 and ~8250 craters for the Apollo 15 regional and landing site maps respectively, ~900 and ~6480 craters for the Apollo 16 maps, and ~830 and ~4110 for the Apollo 17 maps. Once the geologic units on each map are finalized, we can make more detailed age interpretations based on these crater catalogs. [ABSTRACT FROM AUTHOR]

Our team is funded by NASA PDART to produce updated geologic maps of the Apollo 15-16-17 landing sites at regional (1:200,000) and landing site (1:24,000) map scales for publication in the USGS SIM series. Our new maps will incorporate findings and interpretations from nearly 50 years of studies of the original Apollo data, surface observations, and sample analyses, as well as recent remote sensing data. Task 1. Renovation of Pre-Mission Geologic Maps: We have renovated the regional (1:250,000) and landing site (1:50,000) maps for Apollo 15, 16, and 17 pre-mission geologic maps in ArcMap and are in the process of finalizing the GIS file submission to the USGS for archiving. Task 2. Updating the Geologic Map of Apollo 15-16-17 Landing Sites: Mapping of the updated geologic maps continues in year 2 with the focus on defining point features and structural/linear features. We have also included Kaguya Terrain Camera mosaics as supporting data for mapping regional features. Task 3. Determine crater derived ages for new units: Craters ≥500 m have been mapped on the regional (1:200,000) Lunar Reconnaissance Orbiter Wide Angle Camera basemaps and craters ≥10 m have been mapped on the Narrow Angle Camera (NAC) basemaps for each landing site (1:24,000). Once map units are defined, these counts will be used to interpret unit ages on each map. [ABSTRACT FROM AUTHOR]