Sayunei at Night

This image of a Martian rock illuminated by white-light LEDs (light emitting diodes) is part of the first set of nighttime images taken by the Mars Hand Lens Imager (MAHLI) camera at the end of the robotic arm of NASA's Mars rover Curiosity. MAHLI took the images on January 22, 2012 (PST), after dark on the 165th Martian day, or sol, of the rover's work on Mars.

This rock target in the "Yellowknife Bay" area of Mars' Gale Crater is called "Sayunei." The image covers an area about 1.3 inches by 1 inch (3.4 by 2.5 centimeters). The illumination came from one of MAHLI's two groups of white LED pairs. This allowed surface features to cast shadows and provide textural detail.

Photo credit: NASA/JPL-Caltech/MSSS

Note: For more images in this series, see: PIA16712: MAHLI's First Night Imaging of Martian Rock Under Ultraviolet Lighting, PIA16713: First Night Image of MAHLI Calibration Target in White Lighting, and PIA16714: First Night Image of MAHLI Calibration Target Under Ultraviolet Lights. Also, Mars Rover Curiosity Uses Arm Camera at Night.

Sand Dunes in Olympia Undae Over Time

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter snapped this series of false-color pictures of sand dunes in the north polar region of Mars. The area covered in each of the five panels is about 0.8 mile (1.3 kilometers) wide.

The progression begins at left (Panel A) in early spring, when the ground is covered by a seasonal layer of carbon dioxide ice (dry ice) about 2 feet thick. As spring progresses the ice cracks (Panel B), releasing dark sand from the dune below. When pressurized gas trapped below the ice layer is released, it carries along sand and dust to the top of the ice layer, where it is dropped in fan-shaped deposits downhill and downwind (panels C and D). The final panel shows more and more of the dark dunes as the overlying layer of seasonal ice evaporates back into the atmosphere.

The location in this series of images is at 80 degrees north latitude, 122.5 degrees east longitude.

Photo credit: NASA/JPL-Caltech/University of Arizona

Note: For more information, see Thawing 'Dry Ice' Drives Groovy Action on Mars.

Mega Gully Near Echus Chasma

The mega gully in this VIS image empties into Echus Chasma.

Orbit Number: 48563 Latitude: 0.572332 Longitude: 278.937 Instrument: VIS Captured: 2012-11-24 19:58

Photo credit: NASA/JPL/Arizona State University

Channels and Fractures at Claritas Fossae

This VIS image of the Claritas Fossae region illustrates how fractures affect other features. In this instance, the fractures control the path of several channels (from upper right towards lower left). The channels follow the fractures and then follow the slope towards the bottom of the image.

Orbit Number: 48552 Latitude: -41.4612 Longitude: 258.678 Instrument: VIS Captured: 2012-11-23 20:30

Photo credit: NASA/JPL/Arizona State University

Matijevic Hill

As NASA's Mars Exploration Rover Opportunity neared the ninth anniversary of its landing on Mars, the rover was working in the 'Matijevic Hill' area seen in this view from Opportunity's panoramic camera (Pancam). Opportunity landed January 24, 2004, PST (January 25 UTC). The landing site was about 12 miles (19 kilometers), straight-line distance, or about 22 miles (35.5 kilometers) driving-route distance, from this location on the western rim of Endeavour Crater.

Matijevic Hill is an area within the "Cape York" segment of Endeavour's rim where clay minerals have been detected from orbit. This view is centered northwestward, toward the crest of Cape York. It extends more than 210 degrees from left to right. The field of view encompasses most of the terrain traversed by Opportunity during a "walkabout" in October and November 2012 to scout which features to spend time examining more intensely. Two of the features investigated at Matijevic Hill are "Copper Cliff," the dark outcrop in the left center of the image, and "Whitewater Lake," the bright outcrop on the far right.

Opportunity's Pancam took the component images for this mosaic during the period from the mission's 3,137th Martian day, or sol, (November 19, 2012) through Sol 3150 (December 3, 2012).

The image combines exposures taken through Pancam filters centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). The view is presented in approximate true color. This "natural color" is the rover team's best estimate of what the scene would look like if humans were there and able to see it with their own eyes.

Photo credit: NASA/JPL-Caltech/Cornell/Arizona State University

Note: For more information, see PIA16703: 'Matijevic Hill' Panorama for Rover's Ninth Anniversary (for the full-size natural color image), PIA16704: 'Matijevic Hill' Panorama for Rover's Ninth Anniversary (False Color) , PIA16709: 'Matijevic Hill' Panorama for Rover's Ninth Anniversary (Stereo) , and NASA's Veteran Mars Rover Ready to Start 10th Year.

Dittaino Valles

Today's VIS image shows a portion of Dittaino Valles.

Orbit Number: 48551 Latitude: -1.07402 Longitude: 293.526 Instrument: VIS Captured: 2012-11-23 18:18

Photo credit: NASA/JPL/Arizona State University

Carbonate Layering in McLaughlin Crater

This view of layered rocks on the floor of McLaughlin Crater shows sedimentary rocks that contain spectroscopic evidence for minerals formed through interaction with water. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter recorded the image.

A combination of clues suggests this 1.4-mile-deep (2.2-kilometer-deep) crater once held a lake fed by groundwater. Part of the evidence is identification of clay and carbonate minerals within layers visible near the center of this image. The mineral identifications come from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), also on the Mars Reconnaissance Orbiter.

The scene covers an area about one-third of a mile (about 550 meters) across, at 337.6 degrees east longitude, 21.9 degrees north latitude. North is up. Figure 1 [the second, annotated image above] indicates the location of layers bearing clay and carbonate minerals and includes a scale bar of 100 meters (328 feet).

Photo credit: NASA/JPL-Caltech/University of Arizona

Notes: For more information, see Layers with Carbonate Content Inside McLaughlin Crater on Mars. Unfortunately, these images are very low resolution, especially when compared to the very high resolution, very beautiful images the HiRISE team normally provides; however, this is the highest resolution NASA is releasing at this time.

Dunes in a Noachis Terra Crater

Sand dunes on Mars are studied for many reasons. Recent investigations have focused on dune and ripples movement.

In this observation, we look at dunes within a crater in Noachis Terra. Zooming in to one of these areas (and here is the context image) we see the edges of two dunes separated by a field of ripples and rocks. We can compare this area to another image taken two Mars years ago. In the older image, there are many dark wispy features that cover the dunes. These are dust devil tracks, which formed when vortices removed a thin layer of dust off the surface, revealing a darker substrate.

In addition, there are dark sand streaks extending westward from the eastern dune. Blinking between these images shows that virtually all traces of the dust devil tracks and dark streaks have disappeared in the two Mars years. There is also little evidence for dune or ripple movement (however, these images have not yet been orthorectified for a detailed analysis).

In this region, it is likely that dust is periodically deposited and then removed off the dunes. The presence of dust may shield the dunes and ripples from significant movement, such that the observed changes are but thin layers of dust being removed and minor sand streaks that blow off the dunes.

This is a stereo pair with ESP_030080_1245.

Photo credit: NASA/JPL/University of Arizona

Note: The "blink" images, mentioned above, are well worth looking at. Here is the gif file below:

Surface Textures at Planum Australe

Many different surface textures are found on the polar caps. This VIS images shows part of the surface of the south polar cap.

Orbit Number: 48511 Latitude: -86.8588 Longitude: 274.799 Instrument: VIS Captured: 2012-11-20 11:47

Photo credit: NASA/JPL/Arizona State University

John Klein Section of Gale Crater

This view shows the patch of veined, flat-lying rock selected as the first drilling site for NASA's Mars rover Curiosity. The rover's right Mast Camera (Mastcam), equipped with a telephoto lens, was about 16 feet (5 meters) away from the site when it recorded this mosaic's component images, between 3:10 and 3:33 in the afternoon of the 153rd Martian day, or sol, of Curiosity's work on Mars (January 10, 2013).

The area is shot full of fractures and veins, with the intervening rock also containing concretions, which are small spherical concentrations of minerals.The scale bar on the left image is 19.7 inches (50 centimeters) long. On the annotated version, three boxes, each about 4 inches (10 centimeters) across, designate enlargements on the right that illustrate attributes of the area.

Enlargement A shows a high concentration of ridge-like veins protruding above the surface. Some of the veins have two walls and an eroded interior. Enlargement B shows that in some portions of this feature, there is a horizontal discontinuity a few centimeters or inches beneath the surface. The discontinuity may be a bed, a fracture, or potentially a horizontal vein. Enlargement C shows a hole developed in the sand that overlies a fracture, implying infiltration of sand down into the fracture system.

The image has been white-balanced to show what the rocks would look like if they were on Earth.

Photo credit: NASA/JPL-Caltech/MSSS

Note: For more information, see PIA16568: Diversity in Vicinity of Curiosity's First Drilling Target and PIA16702: Neighborhood for Curiosity's First Drilling Campaign. Also, NASA Mars Rover Preparing to Drill Into First Martian Rock.

Channel and Crater Northeast of Hecates Tholus

The origins of channels on Mars is of great interest to understand the history of water.

There are several large (more than 30 kilometers wide) craters on Mars that appear to have spawned channels, perhaps draining from the fresh, hot impact ejecta.

Visible here is a well-preserved (meaning geologically young) crater that is about 3 kilometers wide, and a channel that appears from the margins of the ejecta and flows to the south. Did this small crater generate this relatively large channel?

Most likely the channel was there first, and the crater is younger. However, the channel might have been generated by a larger crater to the northwest.

Photo credit: NASA/JPL/University of Arizona

Note: This image is located west of Phlegra Montes and northeast of Hecates Tholus.

Ice Layering Near Chasma Australe

Today's VIS image shows the multitude of layers making up the South Polar cap.

Orbit Number: 48506 Latitude: -85.8144 Longitude: 95.4964 Instrument: VIS Captured: 2012-11-20 01:53

Photo credit: NASA/JPL/Arizona State University

Mineral Veins at the Sheepbed Unit

This image of an outcrop at the "Sheepbed" locality, taken by NASA's Curiosity Mars rover with its right Mast Camera (Mastcam), shows well-defined veins filled with whitish minerals, interpreted as calcium sulfate.

These veins form when water circulates through fractures, depositing minerals along the sides of the fracture, to form a vein.These veins are Curiosity's first look at minerals that formed within water that percolated within a subsurface environment. These vein fills are characteristic of the stratigraphically lowest unit in the "Yellowknife Bay" area -- known as the Sheepbed Unit.

Mastcam obtained these images the 126th Martian day, or sol, of Curiosity's mission on Mars (December 13, 2012). The view covers an area about 16 inches (40 centimeters) across.A superimposed scale bar is 8 centimeters (3.15 inch) long.

The image has been white-balanced to show what the rock would look like if it were on Earth.

Photo credit: NASA/JPL-Caltech/MSSS

Note: For more information, see PIA16615: Calcium-Rich Veins in Martian Rocks, PIA16616: Signs of Hydrated Calcium Sulfates in Martian Rocks, and PIA16617: Veins in Rocks on Mars and Earth.

Seasonal Erosion near Chasma Australe

Bright carbon dioxide frost (or, dry ice) highlights this network of channels carved into the surface. The channels are eroded a little bit every spring when the seasonal polar cap, composed of dry ice, sublimates (meaning going directly from a solid to gas) at the ice-surface interface. The erosion occurs under the seasonal ice layer: when trapped pressurized gas finds an escape route it carries along loose surface material. This surface material is blown downwind and deposited in dark fans on top of the seasonal ice layer.

The trapped gas finds the weakest easiest escape route. In this area the gas exploited the existing polygonal structure of the surface below. Polygonal terrain is common at high latitudes, and is caused by the thermal contraction and expansion of water ice frozen in the surface dirt.

Photo credit: NASA/JPL/University of Arizona

Note: This image is located near the western edge of Chasma Australe.

Lava Flows in Daedalia Planum

The lava flows in today's VIS image are located on the northeastern margin of Daedalia Planum. Wind deposits are visible in the lee of the flow fronts.

Orbit Number: 48491 Latitude: -2.75786 Longitude: 223.234 Instrument: VIS Captured: 2012-11-18 19:48

Photo credit: NASA/JPL/Arizona State University

Spherules in Yellowknife Bay

This image from the right Mast Camera (Mastcam) of NASA's Curiosity Mars rover shows roughly spherical features. These are called spherules, and they are common in this stratigraphic unit, the Sheepbed Unit, which defines the lower part of the sequences of strata exposed in "Yellowknife Bay." These features are interpreted as concretions, implying they formed in water that percolated through pores in the sediment. Spherical concretions have previously been discovered in other rocks on Mars.

Mastcam obtained these images on the 139th Martian day, or sol, of Curiosity's surface operations (December 25, 2012). The image has been white-balanced to show what the rock would look like if it were on Earth.

Photo credit: NASA/JPL-Caltech/MSSS

Curiosity's Tracks in Gale Crater

This image was acquired for color coverage of the region that the Curiosity rover may explore, but we acquired some extra RED (monochromatic) coverage of the rover tracks.

This image shows the entire distance traveled from the landing site (dark smudge at left) to its location as of 2 January 2013 (the rover is bright feature at right). The tracks are not seen where the rover has recently driven over the lighter-toned surface, which may be more indurated than the darker soil.

Photo credit: NASA/JPL/University of Arizona

Shaler Outcrop

This image from the Mast Camera (Mastcam) on NASA's Mars rover Curiosity shows inclined layering known as cross-bedding in an outcrop called "Shaler" on a scale of a few tenths of meters, or decimeters (1 decimeter is nearly 4 inches). The superimposed scale bar is 50 centimeters (19.7 inches).

This stratigraphic unit is called the Shaler Unit. Decimeter-scale cross-bedding in the Shaler Unit is indicative of sediment transport in stream flows. Currents mold the sediments into small underwater dunes that migrate downstream. When exposed in cross-section, evidence of this migration is preserved as strata that are steeply inclined relative to the horizontal -- thus the term "cross-bedding." The grain sizes here are coarse enough to exclude wind transport. This cross-bedding occurs stratigraphically above the Gillespie Unit in the "Yellowknife Bay" area of Mars' Gale Crater, and is therefore geologically younger.

Mastcam obtained the image on the 120th Martian day, or sol, of Curiosity's surface operations (December 7, 2012).

The image has been white-balanced to show what the rock would look like if it were on Earth.

Photo credit: NASA/JPL-Caltech/MSSS

Note: For more information, see PIA16700: Wide View of 'Shaler' Outcrop, Sol 120.

Yellowknife Bay Veins and Concretions

The right Mast Camera (Mastcam) of NASA's Curiosity Mars rover provided this view of the lower stratigraphy at "Yellowknife Bay" inside Gale Crater on Mars. The rectangle superimposed on the left image shows the location of the enlarged portion on the right. In the right image, white arrows point to veins (including some under the overhang), and black arrows point to concretions (small spherical concentrations of minerals). Both veins and concretions strongly suggest precipitation of minerals from water.

The scale bar in the left image is 50 centimeters (19.7 inches) long. The scale bar in the right image is 10 centimeters (3.9 inches) long.

Mastcam recorded this view in the morning of the 137th Martian day, or sol, of Curiosity's surface operations (December 24, 2012). The image has been white-balanced to show what the rocks would look like if they were on Earth.

Photo credit: NASA/JPL-Caltech/MSSS

Note: For more information, see PIA16701: View from Inside 'Yellowknife Bay'.

Overflow Channel from Athabasca Vallis

A MOC image over this area showed a channel spilling out of the larger Athabasca Vallis (trending east-west at the north end of this image) and flowing to the south.

The channel splits into multiple branches, creating about ten streamlined mesas. Vague bumps were visible on the channel floor in the MOC image--perhaps large boulders that were deposited by floodwaters?

Our HiRISE image reveals the bumps to be rootless cones that form from lava-water interaction. The entire channel system appears to be coated by lava. There are two leading hypotheses for the origin of these channels: (1) they were carved by water and later coated by lava, or (2) the channels were eroded by the lava itself. If eroded by lava, a source of water was still needed to create the rootless cones, but could have been a much smaller quantity of water than that needed to carve the channels.

(The MOC image can be viewed here, but note that it needs to be flipped left-right to correct the geometry.)

Photo credit: NASA/JPL/University of Arizona

Climbing Dunes in Nereidum Montes

This image shows the southern part of a dune field in Nereidum Montes, which is being monitored for changes in dune and ripple positions.

Many of the dunes in this image are overlying steep slopes. The slopes are dipping to the south, yet the dunes, as evidenced by the north-facing orientation of their steep slip faces, are being blown upslope, to the north. Such "climbing dunes" have been found elsewhere on Mars, such as in Valles Marineris and in this case, indicate relatively strong southerly winds.

A close-up image shows one of these slip faces. In addition, several apparent landslide troughs are present. These are interpreted as sand that has slumped down the slope. Subsequently, the wind has remobilized some of the sand and formed climbing ripples within the troughs. This and other HiRISE images show the dynamic interplay between wind and gravity, two of many processes occurring on Mars today.

(Note: view an unannotated version of the subimage with scale bar.)

Photo credit: NASA/JPL/University of Arizona

Snake River Rock

The sinuous rock feature in the lower center of this mosaic of images recorded by the NASA Mars rover Curiosity is called "Snake River." The images in the mosaic were taken by Curiosity's Navigation Camera during the 133rd Martian day, or sol, of the rover's mission on Mars (December 20, 2012).

On Sol 147 (January 3, 2013), Curiosity drove about 10 feet (3 meters) to get a closer look at Snake River for before proceeding to other nearby rocks.

Photo credit: NASA/JPL-Caltech

On the Edge of Yellowknife Bay

In a shallow depression called "Yellowknife Bay," the NASA Mars rover Curiosity drove to an edge of the feature during the 130th Martian day, or sol, of the mission (December 17, 2012) and used its Navigation Camera to record this view of the ledge at the margin and a view across the "bay."

Photo credit: NASA/JPL-Caltech

Note: For more information, see Curiosity Rover Explores 'Yellowknife Bay'.

Copper Cliff by Opportunity

This 180-degree mosaic of images from the navigation camera on the NASA Mars Exploration Rover Opportunity shows terrain near the rover during the 3,153rd Martian day, or sol, of the rover's work on Mars (December 6, 2012). West is at the center, south at the left edge, north at the right edge.

Opportunity had driven about 7 feet (2.2 meters) westward earlier on Sol 3153 to get close to the outcrop called "Copper Cliff," which is in the center of this scene. The location is on the east-central portion of "Matijevic Hill" on the "Cape York" segment of the western rim of Endeavour Crater.

The view is presented as a cylindrical projection.

Photo credit: NASA/JPL-Caltech

Note: For the anaglyph image, see PIA16561: Opportunity at 'Copper Cliff,' Sol 3153.

Matijevic Hill by Opportunity

This full-circle panorama shows the terrain around the NASA Mars Exploration Rover Opportunity during the 3,105th Martian day, or sol, of the rover's work on Mars (October 18, 2012). It was assembled from images taken by the rover's navigation camera. South is at the center. North is on both ends.

Opportunity had driven about 61 feet (18.5 meters) westward earlier on Sol 3105 to reach this location, which is on the northern portion of "Matijevic Hill" on the "Cape York" segment of the western rim of Endeavour Crater. The wheel tracks created by the drive are visible. For scale, the distance between the two parallel tracks is about 3.3 feet (1 meter).

The basin of Endeavour Crater is in the left half of the image. Opportunity has been working on the western rim of Endeavour since mid-2011.

The panorama is presented as a cylindrical projection.

Photo credit: NASA/JPL-Caltech

Note: For the anaglyph image, see PIA16559: Opportunity's Surroundings on Sol 3105, Stereo View.

Opportunity at Whitewater Lake Outcrop

This full-circle panorama shows the terrain around the NASA Mars Exploration Rover Opportunity during the 3,071st Martian day, or sol, of the rover's work on Mars (September 13, 2012). It was assembled from images taken by the rover's navigation camera. South is at the center. North is on both ends.

Opportunity had driven about 34 feet (10.3 meters) the preceding sol to reach this location, which is on part of a relatively flat, light-toned outcrop called "Whitewater Lake." A darker, adjacent outcrop, called "Kirkwood," lies just east of the rover's location and cuts a band through the middle of this view.

The basin of Endeavour Crater is in the left half of the image. Opportunity has been working on the western rim of Endeavour since mid-2011.

The panorama is presented as a cylindrical projection.

Photo credit: NASA/JPL-Caltech

Note: For the anaglyph image, see PIA16557: Opportunity's Surroundings on Sol 3071, Stereo View.

A Circular Crack in Lucus Planum

This circular crack is very odd-looking. When you zoom in to HiRISE scale, the crack looks a lot like a graben.

Canyonlands, Utah is a great place to see grabens on Earth. Grabens form when solid rock is pulled apart. Two cracks form at distinctive angles, and the material between the cracks collapses downward, forming a straight-walled canyon. Well, they're usually straight-walled, but this one is circular, which is unusual.

The first thing anyone thinks of when they see circular features on Mars is a crater. So one hypothesis about how this formed is that an ancient crater was buried by some material, maybe lava or even multiple layers of wet sediments. Because the center of the crater was deeper, more material settled there, and the high-standing rim was only thinly covered. The mantling material solidified and shrank, creating extensional forces.

The heavy central fill pulled downward, cracking the material at the rim where it was thinnest. That's just one guess, though - what else do you think it could be?

References
Buczkowski, D. L. and M. L. Cooke, 2004. Formation of double-ring circular grabens due to volumetric compaction over buried impact craters: Implications for thickness and nature of cover material in Utopia Planitia, Mars, J. Geophys. Res., 109, E02006, doi:10.1029/2003JE002144.

McGill, G. E., 1986. The giant polygons of Utopia, Northern Martian Plains GeoRL 13, 705-708. DOI:10.1029/GL013i008p00705

This is a stereo pair with ESP_029217_1795.

Photo credit: NASA/JPL/University of Arizona

New Impact Site in Fortuna Fossae

This impact site is located on the floor of a large fracture within Fortuna Fossae. This site formed sometime between September 2005 and May 2008 and consists of five distinct craters each displaying individual dark-toned ejecta patterns.

The resulting craters indicate that the impactor broke up into five parts prior to its collision with the surface. Craters continue to form on Mars today and repeat imaging of these recent impacts--especially in the color portion--provides information about how impact features change with time.

Photo credit: NASA/JPL/University of Arizona

Defrosting Landscape Inside Jeans Crater

This image is from the high latitudes in the Southern hemisphere, about half-way through southern spring.

Just like on the Earth, the frost layer that accumulates over the winter will disappear as summer approaches and Mars heats up. However, most of this frost is not made of water ice and snow -- on Mars, most of the frost/ice is made of carbon dioxide (also known as "dry ice").

This material will not melt, but instead will go directly from solid into vapor (a process called sublimation) as it heats up (above approximately 147 K, which is -195 F, or -126 C). In doing so, it'll create all sorts of interesting landforms.

In this image, we can see sublimation spots (small spots where the frost/ice has sublimated away, exposing the darker ground). We also see small fans, which form when jets of gaseous carbon dioxide erupt through a weak spot in the surface ice, ejecting dark surface material that then gets smeared across the surface by the wind (so the different directions of the fans show us how the wind varies across this landscape).

Large darker "flows" are also visible; these are avalanches of material that extend downslope (and scientists are still debating if flows are dry or wet features). In the next few weeks, more of these features will appear and grow, until Mars heats up enough for all of the frost and ice (and sublimation features) to disappear.

References:
Gardin, E., et al. (2010). Defrosting, dark flow features, and dune activity on Mars: Example in Russell crater. J. Geophys. Res. 115, E06016.

Hansen, C.J., et al. (2010). HiRISE observations of gas sublimation-driven activity in Mars' southern polar regions: I. Erosion of the surface. Icarus 205, 283-295.

Kereszturi, A., et al. (2009). Recent rheologic processes on dark polar dunes of Mars: Driven by interfacial water? Icarus 201, 492-503.

Photo credit: NASA/JPL/University of Arizona

Note: This image is located inside Jeans Crater, which itself is located in Terra Cimmeria.

Layers, Dunes and Cliffs in Hydrae Chasma

Hydrae Chasma is a deep, circular depression approximately 50 kilometers across, situated between Juventae Chasma to the north and the large canyon system Valles Marineris to the south. The Chasma has steep walls flanked by numerous landslides and a massive scarp along its southern boundary where the surface has collapsed into this depression.

This closeup is of an isolated flat-topped mountain (known as a mesa) rising out of a sea of dunes located in the center of Hydrae Chasma. Darker-toned dunes, likely composed of basaltic sands, form an apron along the base of the mesa's northern margin. The western side of the mesa is gently sloping and is composed of a highly fractured light-toned rubbly base. It is overlaid by alternating light and dark layered cliff-forming units and is covered by a sediment cap containing still more dunes.

The layered sequences are present only in the interior deposits and not in the walls of the Chasma. Similar deposits are located on the floors of Valles Marineris and other chasmata and may be the sediment remnants of ancient lakes formed within these canyon systems.

Photo credit: NASA/JPL/University of Arizona

Charitum Montes Topographical Map

This color-coded overhead view is based on an ESA Mars Express HRSC digital terrain model of the region, from which the topography of the landscape can be derived. The color coding shows the very edge of the Charitum Montes mountain region at the top of the image, with the highest elevation, while the subtle pedestal craters that dot the image almost fade away with just a small amount of relief difference between the elevated ejecta and the surrounding area. Centered at around 53°S and 334°E, the image has a ground resolution of about 20 m per pixel. The image was taken during revolution 10778 on 18 June 2012.

Image credit: ESA/DLR/FU Berlin (G. Neukum)

Charitum Montes Anaglyph

Charitum Montes imaged during revolution 10778 on 18 June 2012 by ESA’s Mars Express using the High-Resolution Stereo Camera (HRSC). Data from HRSC’s nadir channel and one stereo channel have been combined to produce this anaglyph 3D image that can be viewed using stereoscopic glasses with red–green or red–blue filters. Centered at around 53°S and 334°E, the image has a ground resolution of about 20 m per pixel.

Photo credit: ESA/DLR/FU Berlin (G. Neukum)

New Impact Crater South of Echus Chasma

How exactly can we tell if an impact crater is new?

In this observation, we see a dark spot with a larger, rayed "blast zone" that was also apparent in a Context Camera image taken in 2011 (an instrument with a larger footprint than HiRISE and also on the Mars Reconnaissance Orbiter). However, a THEMIS image of the same area acquired in 2009 does not show the dark spot at all.

This is a great example of using three different instruments to view the same area not only to look for changes in the Martian landscape, but also to use the resolution of HiRISE to determine if this is indeed a new impact site.

Photo credit: NASA/JPL/University of Arizona

Note: This impact crater is located just south of Echus Chasma.

Bright and Dark Slope Streaks in Arabia Terra

While HiRISE has imaged slope streaks before, bright streaks are not as common as dark ones, so they're of high interest.

Slope streaks are generally small features, and have an interior roughness that is finer than the width of the streak itself. A high resolution image can help identify the characteristics of this roughness.

Additionally, studying these streaks can shed light on the "life cycle" of a streak and the geologic processes that created them. We may also be able to study the photometric properties of the streaks.

(Note: the above image is not map-projected, so north is approximate down).

Photo credit: NASA/JPL/University of Arizona

Pedestal Crater in Malea Planum

As the name suggests, pedestal craters usually have ejecta (material thrown out from impact) that is above the surrounding terrain. In some cases, the material can be more erosion-resistant. Some suggest that these units were once rich in volatiles (e.g., water ice).

This specific pedestal in Malea Planum is one of the largest on Mars, and fine layering is visible along its margins.

Photo credit: NASA/JPL/University of Arizona

Dune Migration in Vastitas Borealis

This image shows large sand dunes in the North Polar sand sea on Mars. It is one of a series of repeat images of the same dunes, taken at different times, in order to determine the type and extent of changes in the dunes over time.

Dunes tend to migrate slowly on Earth under continuous wind regimes (on the order of several to tens of meters per year), and we are just starting to verify movement on Martian dunes with these repeat HiRISE images.

In addition to migration of the dune, we will also use these repeat images to look for changes in the dune shape and avalanches down the slip face. Analyzing these changes will help us better understand the interaction between the atmosphere and the surface of Mars.

Photo credit: NASA/JPL/University of Arizona

Unusual Spherules at Cape York

Small spherical objects fill the field in this mosaic combining four images from the Microscopic Imager on NASA's Mars Exploration Rover Opportunity. The view covers an area about 2.4 inches (6 centimeters) across, at an outcrop called "Kirkwood" in the Cape York segment of the western rim of Endeavour Crater. The individual spherules are up to about one-eighth inch (3 millimeters) in diameter.

The Microscopic Imager took the component images during the 3,064th Martian day, or sol, of Opportunity's work on Mars (September 6, 2012). For a color view of the Kirkwood outcrop as Opportunity was approaching it two weeks earlier, see PIA16128.

Opportunity discovered spherules at its landing site more than eight-and-a-half years earlier. Those spherules were nicknamed "blueberries." They provided important evidence about long-ago wet environmental conditions on Mars because researchers using Opportunity's science instruments identified them as concretions rich in the mineral hematite deposited by water saturating the bedrock. A picture of the "blueberries" from the same Microscopic Imager is PIA05564.

The spherules at Kirkwood do not have the iron-rich composition of the blueberries. They also differ in concentration, distribution and structure. Some of the spherules in this image have been partially eroded away, revealing concentric internal structure. Opportunity's science team plans to use the rover for further investigation of these spherules to determine what evidence they can provide about ancient Martian environmental conditions.

Photo credit: NASA/JPL-Caltech/Cornell University/USGS/Modesto Junior College

Note: For more information, see NASA Mars Rover Opportunity Reveals Geological Mystery.

Wind Streaks Northwest of Unranius Tholus

This image of a wind streak monitoring site northwest of Uranius Tholus shows dramatic differences from earlier images and evidence for two distinct processes of Martian wind erosion.

Located near the northern end of the Tharsis rise at a moderate elevation (1800 meters above datum), the site is in a region of high albedo and low thermal inertia that suggest a thick mantle of dust. The first subimage shows some of the changes that have occurred since the site was last imaged in January, 2009 (ESP_011465_2075). Bright dust has been scoured from the surface by strong southerly winds (blowing from the top right in these unprojected images). Bright streaks trail downwind from impact craters, protected from the wind in the lee of the crater rims. Sharp dark streaks edged upwind as the dust was stripped away. At least two different episodes of erosion with slightly different wind directions can be inferred from the orientations of the dark streaks. Yet another wind direction is indicated by the few dune-like ripples that can be seen in the floor of the valley. These features were shaped by much older winds that were probably controlled by local topography.

The second subimage shows the second erosion process, the tracks of dust-devils across the newly cleaned surface (just south of the first subimage). What makes these tracks interesting is that they are bright! Most dust-devil tracks on Mars are dark, forming when a whirlwind lifts bright dust off the surface and exposes a darker substrate. These tracks were neither visible in the earlier HiRISE image, nor in an earlier image (PSP_002222_2075) acquired in January, 2007. The cause of the bright tracks is unclear.

Bright dust-devil tracks were also spotted by the Mars Orbital Camera in southern Schiaparelli Crater, a region also dominated at the time by wind streaks. One way to make bright tracks would be to excavate through dark material (such as a lag of basaltic sand) to a brighter substrate. Another possibility is that the dust-devils stir up the remaining pockets of bright dust that are hiding from the prevailing winds in the shelter of topographic obstacles.

Photo credit: NASA/JPL/University of Arizona

Colorful Surface Near Nili Fossae

This enhanced-color image shows a surface with diverse colors just southwest of Nili Fossae. The color diversity of this mesa suggests that the surface has a varied composition, perhaps recording chemical processes of ancient Mars.

Much of the surface shows a chaotic mix of colors, but the northern impact crater exposes distinct layers. Different layers have different colors. There are several possible reasons for this: the events that formed the layers could have drawn material from different sources, or the layers could have been altered differently after they formed, for reasons such as varying porosity.

This is a stereo pair with ESP_019898_2000.

Photo credit: NASA/JPL/University of Arizona

Mounds in Chryse Planitia

The mounds in this observation may have been formed by a process called "diapirism," where material at depth is more buoyant (i.e., lower density) than the surrounding rocks so it rises to the surface.

Why might this be of interest? At HiRISE resolution, we might be able to study the uplifted material more closely, such as if there are clays or other aqueous materials present. If these mounds were formed by diapirism, it offers a deeper window into the Martian past. This area could also be an interesting site for a future exploration rover.

This is a stereo pair with ESP_026284_2060.

Photo credit: NASA/JPL/University of Arizona

Let it snow, let is snow, let it...

Observations by NASA's Mars Reconnaissance Orbiter have detected carbon-dioxide snow clouds on Mars and evidence of carbon-dioxide snow falling to the surface.

Deposits of small particles of carbon-dioxide ice are formed by snowfall from carbon-dioxide clouds. This map shows the distribution of small-grain carbon-dioxide ice deposits formed by snowfall over the south polar cap of Mars. It is based on infrared measurements by the Mars Climate Sounder instrument on the Mars Reconnaissance Orbiter.

Image credit: NASA/JPL-Caltech

Note: For more information, see NASA Observations Point to 'Dry Ice' Snowfall on Mars.

3-D View from Bradbury Landing

This 3-D image from NASA's Curiosity was taken from the rover's Bradbury Landing site inside Gale Crater, Mars, using the left and right eyes of its Navigation camera. Between the rover on the right, and its shadow on the left, looms the rover's eventual target: Mount Sharp. The mountain's highest peak is not visible to the rover from the landing site.

This full-resolution, 360-degree stereo panorama was taken on sols 2 and 12 of the mission, or the 2nd and 12th Martian days since landing (Aug. 8 and 18, 2012). It requires viewing with the traditional red-blue 3-D glasses, with red going over the left eye.

Image credit: NASA/JPL-Caltech

The MSL Sky Crane Crash Site by HiRise

After a rocket-powered descent stage, also known as the sky crane, delivered NASA's Curiosity rover to Mars on August 5 PDT (August 6 EDT), 2012, it flew away and fell to the surface. Possible multiple impacts from that collision are revealed in blue in this enhanced-color view taken by the High-Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

The main crash site is seen at right, shaped like a fan. Farther from the site are several smaller dark spots, which are thought to be secondary impacts from debris that continued to travel outward. The impact sites are darker because the lighter, reddish top layer of soil was disturbed, revealing darker basaltic sands underneath.

The full image for these observations can be seen at http://uahirise.org/releases/msl-tracks.php.

Photo credit: NASA/JPL-Caltech/Univ. of Arizona

Opportunity's Surroundings on its 3,000th Sol

This 360-degree panorama assembled from images taken by the navigation camera on NASA's Mars Exporation Rover Opportunity shows terrain surrounding the position where the rover spent its 3,000th Martian day, or sol, working on Mars (July 2, 2012). Opportunity completed its 90-sol prime mission in April 2004. It has continued to explore the Meridiani Planum region of Mars for more than eight years of bonus extended missions.

The Sol 3000 site is near the northern tip of the Cape York segment of the western rim of Endeavour Crater. Bright toned material lines the perimeter of Cape York.

This panoramic view is centered to the south, with north at both ends. The component images were taken during sols 2989 through 2991.

Opportunity arrived at this location on Sol 2989 (June 20, 2012) with a drive bringing the mission's total driving distance as of Sol 3000 to 21.432 miles (34,492 meters). Here it examined a rock target called "Grasberg" with its microscopic imager and alpha particle X-ray spectrometer, both before and after grinding the surface off the target with the rover's rock abrasion tool. Opportunity departed this location with an eastward drive of about 105 feet (32 meters) on Sol 3008 (July 10, 2012).

The scene is presented as a cylindrical projection in this image.

Photo credit: NASA/JPL-Caltech

Note: For other images from this location, see: PIA16123: Opportunity's Surroundings on 3,000th Sol, in 3-D, PIA16124: Opportunity's Surroundings on 3,000th Sol, Polar Projection, and PIA16125: Opportunity's Surroundings on 3,000th Sol, Vertical Projection.

Rock Fins at Cape York

Rock fins up to about 1 foot (30 centimeters) tall dominate this scene from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity. The component images were taken during the 3,058th Martian day, or sol, of Opportunity's work on Mars (August 23, 2012). The view spans an area of terrain about 30 feet (9 meters) wide.

Orbital investigation of the area has identified a possibility of clay minerals in this area of the Cape York segment of the western rim of Endeavour Crater.

The view combines exposures taken through Pancam filters centered on wavelengths of 753 nanometers (near infrared), 535 nanometers (green) and 432 nanometers (violet). It [the top image] is presented in approximate true color, the camera team's best estimate of what the scene would look like if humans were there and able to see it with their own eyes.

Image credit: NASA/JPL-Caltech/Cornell University/Arizona State University

Note: The top picture is natural color, the second picture is an anaglyph image, and the third picture is false color.

Hadley Crater

High-Resolution Stereo Camera (HRSC) nadir and color channel data taken during revolution 10572 on 9 April 2012 by ESA’s Mars Express have been combined to form a natural-color view of Hadley Crater. Centered at around 19°S and 157°E, the image has a ground resolution of about 19 m per pixel. The image shows the main 120 km wide crater, with subsequent impacts at later epochs within it. Evidence of these subsequent impacts occurring over large timescales is shown by some of the craters being buried.

Photo credit: ESA/DLR/FU Berlin (G. Neukum)