30 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes in the north polar region of Mars. In this springtime view, the dunes are largely covered by frozen carbon dioxide that was deposited during the winter months in the northern hemisphere. Dark spots indicate areas where the frost has begun to either sublime away, acquire a roughened texture, or both.
Location near: 77.3°N, 95.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
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In June 2000, we reported the discovery, using the Mars Global Surveyor's Mars Orbiter Camera, of very youthful-looking gullies found on slopes at middle and high latitudes on Mars. Since that time, tens of thousands of gullies have been imaged by all of the Mars orbiting spacecraft: Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter.
During the years since the original June 2000 report, the Mars Global Surveyor's camera was used to test the hypothesis that the gullies may be so young that some of them could still be active today. The test was very simple: re-image gullies previously seen by the camera and see if anything has changed.
In two cases, something changed. One of those cases is presented here. A gully on the wall of an unnamed crater in Terra Sirenum, at 36.6 degrees south, 161.8 degrees west, was initially imaged by the camera on Dec. 22, 2001 (Figure A, left). It showed nothing noteworthy at the location where a change would later be observed, but a group of nearby gullies exhibited an unusual patch of light-toned material. As part of our routine campaign to re-image gully sites using the camera, another image of this location was acquired on April 24, 2005. A new light-toned deposit had appeared in what was otherwise a nondescript gully (Figure A, right). This deposit was imaged again by the camera on Aug. 26, 2005, at a time when the sun angle and season were the same as in the original December 2001 image, to confirm that indeed the light-toned feature was something new, not just a trick of differing lighting conditions. In August 2005, the feature was still present.
Figure A: This set of images shows a comparison of the gully site as it appeared on Dec. 22, 2001 (left), with a mosaic of two images acquired after the change occurred (the two images are from Aug. 26, 2005, and Sept. 25, 2005). Sunlight illuminates each scene from the northwest (top left). The 150-meter scale bar represents 164 yards.
Figure B: This is a mosaic of images that cover the entire unnamed crater in Terra Sirenum. The location of the light-toned gully deposits, old and new, is indicated. This is a mosaic of images acquired by the camera in 2005 and 2006. The 500-meter scale bar equals approximately 547 yards.
Figure C: This image shows an enlargement of a portion of another image from August 2005, showing details of the new, light-toned gully deposit. The new material covers the entire gully floor, from the point at which the gully emerged from beneath a mantled slope, down to the spot at which the channel meets the crater floor. At this break in slope, the gully material, as it was emplaced, spread out into five or six different fingers (this is called a "digitate" termination as in finger digits). The 75-meter scale bar represents a distance of about 82 yards.
Figure D: To confirm that the new, light-toned gully deposit is not just a trick of changing illumination conditions as the sun rises to different levels in the sky each season, the Mars Orbiter Camera team repeatedly imaged this site throughout 2005 and 2006. Four examples are shown here, acquired in April 2005, August 2005, February 2006 and April 2006. The "i=" indicates solar-incidence angle, or the height of the sun in the local sky, relative to a case where the sun would be directly overhead (i=0 degrees). Thus, the higher the incidence angle, the lower the sun would appear in the sky to an observer on the ground.
These images show that a material flowed down through a gully channel, once between December 2001 and April 2005. After the flow stopped, it left behind evidence -- the light-toned deposit. The deposit is thin enough that its thickness cannot be measured in the camera's 1.5-meters-per-pixel images. However, it does exhibit a digitate termination, suggesting that the material flowed in a fluid-like manner down the approximately 25 degree slope before splaying out into multiple small lobes at the point where the crater wall meets the crater floor and the slope suddenly drops to near zero. This deposit, and a similar one in a crater in the Centauri Montes, together suggests that the materials involved were low-volume debris flows containing a mixture of sediment and a liquid that had the physical properties of liquid water. In this case, we propose that the water came from below the surface, emerged somewhere beneath the mantle covering the original crater wall, and then ran down through a previously existing gully channel. No new gully was formed, but an old one was re-activated.
The light tone of the new gully deposit, and that of the older, neighboring gullies, is intriguing. We cannot know from these images whether the light tone indicates that ice is still present in and on the surface of the deposit. Indeed, ice may not be likely: under present conditions on the surface of Mars, ice would be expected to have sublimed, or vaporized, away fairly shortly after the new deposit formed. However, the light-toned material could be frost that forms and re-forms frequently as trapped water-ice sublimes and "exhales" from within the deposit. Alternatively, the light-tone may result if the deposit consists of significantly finer grains (for example, fine silt) than the surrounding surfaces, or if the deposit's surface is covered with minerals such as salts formed as water evaporated from the material.
Do these images prove that water has flowed on Mars? No, they cannot. However, they provide the first very tantalizing evidence that this may have occurred. While the surface environment on Mars is extremely dry, drier than the most arid deserts on Earth, liquid water from beneath the Martian surface may have come out of the ground and flowed across this little portion of the red planet in this decade.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
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The Mars Global Surveyor's Mars Orbiter Camera has found that meteorites are hitting the Martian surface and forming new craters all the time. If you were living on Mars, chances are that within 10 or 20 years, an impact would occur close enough to where you live that you'd notice it -- perhaps you'd hear the impact and it would startle you out of your seat.
A year ago, it had not occurred to the camera team that they could find places on Mars where meteorites had impacted the surface during the course of the mission. Such craters, if they were forming at all, would be a few meters to a few tens of meters across; much too small to notice (or so they thought) in the wide-angle camera coverage. But, on Jan. 9, 2006, they began to realize that not only could we find such craters, we might also be able to characterize the present-day impact cratering rate on Mars. Surveying for fresh craters formed during the mission would provide the first direct observation -- for any body in the solar system, including Earth and its Moon -- of the present-day cratering rate. This in turn can help test models used all the time by members of the scientific community to estimate the age of features on planetary surfaces.
The first fresh impact site, shown on this page, was first noticed on Jan. 9, 2006, in an image acquired three days earlier. The image was acquired by the wide-angle camera at its highest possible spatial resolution, about 240 meters (262 yards) per pixel. To the northwest of the area imaged by the narrow-angle camera, the red, wide-angle context frame showed a dark spot. This spot was not present in any previous image acquired by any spacecraft, from Mariner 9 (which arrived in 1971) on down through Mars Express (which arrived in 2003).
Figure A: The first figure shows two red, wide-angle camera context images. The first was taken on June 9, 2001, several years before the impact occurred. The second is the "discovery" image, acquired on January 6, 2006. In both cases, a white box indicates the location of the Mars Orbiter Camera narrow-angle image for which the context image was obtained. For scale, the white boxes are 3 kilometers (1.9 miles) wide.
Figure B: In this image, North is up in this map-projected view. The single, broad dark streak that emanates from the impact site and points toward the southwest (lower left) may indicate either the direction that the meteor came from, or its opposite. If it represents the direction that the impactor came from, then the streak results from disruption of dust on the Martian surface as the object came in. If the opposite, then it represents the direction that material was blasted from the impact site, away from the direction that the meteor came. In either case, the impactor came in at a somewhat oblique angle, and broke up just before hitting the ground, because it formed multiple small craters. The 300-meter scale bar represents 328 yards.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
18 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark dunes on a crater floor during the southern spring. Some of the dunes have frost on their south-facing slopes.
Location near: 52.3°S, 326.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Spring
8 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned ripples covering the floors of troughs in the Adamas Labyrinthus region of northern Elysium Planitia. The ripple crests generally run perpendicular to the trend of each trough, indicating that the dominant winds involved in shaping these ripples blow up and down, through the troughs, independent of the direction of winds that blow across the plains outside the troughs.
Location near 32.7°N, 251.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
24 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows billowing clouds of dust rising from a storm southeast of Hellas Planitia. The dust storm in this case obscured the Mars Orbiter Camera's view of the martian surface.
Location near: 62.2°S, 259.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
24 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the contact between a group of yardangs, tapered ridges formed by the removal of relatively easily-eroded material (e.g., sedimentary rock) and a concentration of dark-toned windblown sand on the floor of a crater in the Terra Sabaea region of Mars.
Location near: 1.4°N, 333.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
6 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the remains of leveed lava channels cutting across (west to east) a dust-covered plain composed of overlapping lava flows east of Olympus Mons, a giant volcano in the Tharsis region of Mars.
Location near: 22.3°N, 122.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
24 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the south polar residual cap of Mars. The bright, relatively homogeneous-appearing material extending from top (north) to bottom (south) is mainly composed of solid carbon dioxide. During the martian summer months, sublimation, the direct conversion of a solid to a gas, causes the scarps that delineate the edges of the bright material to retreat by approximately 3 meters (around 10 feet) before autumn begins.
Location near: 87.1°S, 94.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
17 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows mesas and pits formed by sublimation of carbon dioxide of the south polar cap.
Location near: 85.8°S, 351.5°W
Image width: ~2 km (~1.2 mi)
Illumination from: upper left
Season: Southern Summer
31 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a pedestal crater superposed on the floor of the much larger Mellish Crater. When an impact crater of this type forms, material is thrown onto the adjacent terrain to form portions of the ejecta blanket we see today. If the ejecta blanket is sufficiently rocky, it will protect the underlying terrain from wind erosion. Over time, much of the exposed material surrounding the ejecta blanket will be removed by wind, leaving behind the rocky ejecta and the material below it, resulting in the pedestal-like appearance seen here.
Location near: 73.0°S, 22.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
19 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a sand dune field in the north polar region of Mars. The dunes are covered with frozen carbon dioxide which accumulated over the autumn and winter months in the northern hemisphere. During the spring, the time at which this image was acquired, the carbon dioxide begins to sublime away, going directly from solid to gas, just as dry ice does here on Earth. The dark spots, streaked by blowing winds, may be places where the frost has been removed (exposing underlying dark sand), places where the grain size or roughness of the frost has increased (increasing shadowing due to the change in texture), or both.
Location near: 79.7°N, 148.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
13 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dried streambeds -- martian gullies -- in the mountainous central peak region of Hale Crater. Some scientists have suggested that the fluid which carved these gullies was liquid water, and that it either resulted from ancient snowmelt or from release of groundwater that percolated to the surface in the intensely fractured rock of Hale's central peak. In either case, the gullies are dry today, and dark sand can be seen as dunes near the right/lower right part of the image.
Location near: 35.8°S, 36.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
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The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) captured two examples of gullies on crater walls in which a change occurred between 1999 and 2005. In each case, one in Terra Sirenum (see PIA09027 or MOC2-1618), the other in the Centauri Montes (see PIA09028 or MOC2-1619), new light-toned material was deposited during the MGS mission. These new light-toned deposits may be indicators that water flowed at these two gully sites during the past few years. Naturally, a question arises: are there other gullies at which similar light-toned deposits have formed?
To answer the question, the MOC team at Malin Space Science Systems (MSSS) reviewed every MOC image ever taken of a martian gully. Most of the gullies occur at middle latitudes in both the northern and southern hemispheres. This re-examination turned up several good examples of other light-toned materials deposited in gullies. However, in none of these cases is there a "before" image, with no light-toned material, followed by an "after" image in which new light-toned material had appeared. Thus, one cannot know how long ago these other light-toned deposits formed. However, these are excellent candidates for future monitoring with orbiter cameras that have sufficient spatial resolution to look for new light-toned deposits, should they form during the coming years. Shown here are three of the best examples the MOC team identified.
Figure A: This image shows several gullies with light-toned material on their floors and deposited in their aprons. This area is located on the northeast wall of Hale Crater near 35.5°S, 35.4°W. The picture is a mosaic of MOC images R07-02277 (acquired 31 July 2003), R13-01791 (acquired 11 January 2004), and S16-01780 (acquired 21 March 2006). The 500 meter scale bar is 547 yards long.
Figure B: This image shows a portion of the south wall of an unnamed crater on the northern plains of Mars, near 59.0°N, 277.7°W. As in the previous example, the material deposited after movement through the gully channel is light-toned. A portion of another gully is seen on the left edge of the picture. This is a sub-frame of MOC image R01-00902, acquired on 19 January 2003.
Figure C: This picture is a mosaic of MOC images M11-00286 (acquired 2 January 2000), S13-01274 (acquired 13 December 2005), and R09-01804 (acquired 16 September 2003). The arrows point to several light-toned gully deposits that were observed at this location, the wall of a deep pit formed in a large crater nearly filled with layered, boulder-producing rock. These features are located in Noachis Terra near 47.2°S, 355.8°W.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
The team managing NASA's Mars Exploration Rover Opportunity had set 'Victoria Crater' as a long-term destination even before the rover climbed out of 'Endurance Crater' in December 2004. As of early September 2006, Opportunity has driven more than 7.2 kilometers (4.5 miles) since leaving Endurance and is approaching Victoria.
Victoria is the large crater near the bottom of this map made from images taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor. The gold line traces Opportunity's path eastward then southward from "Eagle Crater," where it landed, to Endurance Crater, where it spent six months, and nearly to Victoria. The south end of the line indicates Opportunity's location as of the rover's 930th Martian day, or sol, (Sept. 5, 2006). Victoria is about 750 meters (0.47 mile) in diameter, or about six times wider than Endurance and about 35 times wider than Eagle. The scale bar at lower right shows the length of 800 meters (0.50 mile). North is up.
23 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows channels on the plains southeast of Olympus Mons.
Location near: 16.0°N, 129.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Autumn
21 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small portion of the floor of Kaiser Crater in the Noachis Terra region, Mars. The terrain in the upper (northern) half of the image is covered by large windblown ripples and a few smoother-surfaced sand dunes. The dominant winds responsible for these features blew from the west/southwest (left/lower left).
Location near: 47.2°S, 341.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
25 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows part of a dune field in Chasma Boreale, the large north polar trough. The bright material covering the dunes is frozen carbon dioxide. This carbon dioxide frost accumulates during the northern autumn and winter, and sublimes away (turns directly from solid to gas) during the spring and summer. The image was acquired near the end of the northern spring. The dark areas in this image are places where the frost sublimed away, revealing the coarse dark sand of the dunes.
Location near: 84.5°N, 19.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
24 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes in Arkhangelsky Crater, named for A. D. Arkhangelsky (1879-1940), an influential, early Russian geologist. The steepest slopes on these dunes, their slip faces, point toward the northeast (upper right), indicating formative winds from the southwest.
Location near: 41.3°S, 25.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
23 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small volcano in the Syria Planum region of Mars. Today, the lava flows that compose this small volcano are nearly hidden by a mantle of rough-textured, perhaps somewhat cemented, dust. The light-toned streaks that cross the scene were formed by passing dust devils, a common occurrence in Syria.
Location near: 13.0°S, 102.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
23 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a tongue of debris at the base of the wall of a large crater in Terra Tyrrhena. The tongue is the combined product of landsliding and emplacement of crater ejecta-a ~3 km (1.9 mi) wide impact crater formed on the rim of the larger crater and, when it did, it caused the movement which created the tongue. About one third of the crater that caused this can be seen near the southwest (lower left) corner of the image.
Location near: 21.1°S, 270.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
16 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark wind streaks streaming across lava flow surfaces in eastern Tharsis, west of the Kasei Valles region.
Location near: 8.5°N, 85.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
14 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a typical view of polygon-cracked and pitted surfaces unique to western Utopia Planitia. No other place on Mars has this appearance. Some Mars scientists have speculated that ground ice may be responsible for these landforms.
Location near: 42.3°N, 275.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
15 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the very edge of the south polar residual cap of Mars. The bright areas, which appear somewhat like pieces of sliced Swiss cheese, are composed mainly of frozen carbon dioxide. The scarps around the edges of the carbon dioxide mesas have been retreating at a rate of roughly 3 meters (~3 yards) per martian year; in this case, exposing a darker surface that lies below.
Location near: 85.4°S, 88.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
The route followed by NASA's Mars Exploration Rover Opportunity from its landing site through the 1,215th Martian day (or sol) of its mission (June 24, 2007), is marked on this map. The underlying image is from the Mars Observer Camera on NASA's Mars Global Surveyor orbiter.
26 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown sand dunes on the southeastern floor of Herschel Crater.
Location near: 15.7°S, 228.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
21 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a martian valley, perhaps long, long ago carved by a liquid such as water, in northern Terra Cimmeria. The channel that might have once run down through the valley is no longer visible; the floor is covered with large, light-toned, windblown ripples.
Location near: 5.7°S, 227.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
18 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows neighboring networks of gullies in the northwest wall of a south middle-latitude crater west of Hellas Planitia. The faint crisscrossing streaks, also observed on the wall of the crater, are evidence of passing dust devils, a common phenomenon in this region. The gullies might have formed by erosion caused by running water, mixed with debris.
Location near: 16.4°N, 92.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
23 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows sinuous ridges and other landforms exposed by erosion in the Aeolis region of Mars. The ridges in this scene indicate the locations of ancient channels in a fan of sediment deposited in this region. Over time, wind erosion has removed surrounding materials and left the channels, which had been filled by sediment, standing as ridges.
Location near: 4.5°S, 205.2°W
Image width: ~2 km (~1.2 mi)
Illumination from: upper left
Season: Southern Autumn
25 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows terrain in eastern Isidis Planitia that is very heavily peppered with impact craters of diameters of a few hundred meters (a few hundred yards) or less. One aim of the MGS MOC Picture of the Day series is to showcase the rich variety of martian surfaces; this one should be compared with other Pictures of the Day in recent weeks, as most of these are shown covering an area of about the same width, approximately 3 kilometers (1.9 miles).
Location near: 17.5°N, 263.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
26 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a flood-carved canyon within the larger Kasei Valles system on Mars. This canyon is the result of the very last flood event that poured through the Kasei valleys, long ago.
Location near: 21.1°N, 72.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
9 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of Syrtis Major Planum, dominated in this area by two impact craters of differing age. The large one is about 1.3 kilometers (0.8 miles) in diameter, the smaller is about 250 meters (~820 feet) across. The smaller crater has a well-defined ejecta blanket and rays emanate outward from its center. The larger crater does not exhibit these features. The larger one is older, and its ejecta blanket and rays have been removed and degraded over time.
Location near: 5.4°N, 294.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
25 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a spectacular summertime view of a portion of the south polar residual cap. Large, semi-continuous mesas are separated by circular and other oddly-shaped depressions. These features are all formed in frozen carbon dioxide; the scarps which bound the mesas and pit walls retreat at a rate of about 3 meters (a little more than 3 yards) each martian southern summer.
Location near: 87.7°S, 357.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
21 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows sand dunes overlain by a layer of seasonal carbon dioxide frost in the north polar region of Mars. Sunlight illuminates the scene from the lower left, but slopes facing toward the upper right seem illuminated because of the thicker accumulation of frost on the slopes facing away from the sunlight.
Location near: 76.3°N, 264.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
3 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a group of gullies formed on the equator-facing wall of a north mid-latitude crater. Gullies such as these might have formed from the erosive forces of liquid water.
Location near: 49.4°N, 56.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
Click on the image to view the animation
Lower resolution animation
This movie maps out the travels of NASA's Mars Exploration Rover Opportunity, from is landing site at Eagle Crater to the rim of Victoria Crater about six miles (9.7 kilometers) away. The rover, which landed on the red planet more than three years ago, spent 21 months trekking across the plains of Meridiani Planum from Endurance Crater to reach Victoria Crater on sol 951 (Sept. 26, 2006).
Victoria is the largest crater encountered by Opportunity yet, at 800 meters (half a mile) across. Once there, the rover began to explore the rim of the crater, working around its sharp cliffs and gentle bays in a clockwise direction. It examined the cliffs' rock layers visible from rim viewpoints and it assessed the bays for a possible entry route. Opportunity then headed back to its original arrival point at Victoria, an alcove informally named "Duck Bay," where it is expected to roll into the crater in early July 2007.
The images making up the first map in this movie are from the Mars Observer Camera on NASA's Mars Global Surveyor, while the second map uses an image from the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter.
27 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dust plumes created by gusting winds on a plain southwest of Argyre Planitia.
Location near: 67.0°S, 75.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
6 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two troughs in the Hephaestus Fossae region surrounded by heavily cratered terrain.
Location near: 22.7°N, 239.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
20 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of light-toned sedimentary rocks in west Candor Chasma.
Location near: 6.6°S, 75.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
21 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows cracked, layered plains-forming material in the western part of Utopia Planitia, Mars. Investigators have speculated that ice might be -- or might once have been -- present in the ground, and changes in temperature and the amount of ice over time may have led to the formation of these cracks. But no one is certain just how these features formed.
Location near: 45.0°N, 276.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
7 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows channels carved into the plains southeast of the large volcano, Olympus Mons. The fluid that created these landforms flowed from upper right toward the lower left, but its nature is unknown. Today, the entire scene is mantled with dust.
Location near: 16.0°N, 129.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Autumn
10 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered sedimentary rocks and the traces of valleys that were once underneath those rocks in northwestern Sinus Meridiani.
Location near: 4.5°N, 2.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
30 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows crescent-shaped, scooped-out hollows where wind has eroded the local bedrock in the Apollinaris Sulci region.
Location near: 11.8°S, 179.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Southern Summer
8 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies on a large slip face in the Russell Crater dune field. When the image was acquired, the dunes were still covered with seasonal frost.
Location near: 54.7°S, 347.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
8 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes in the north polar region of Mars. The dunes in this scene are covered by a layer of carbon dioxide frost that accumulated during the winter in 2005. Dark spots indicate areas where frost has begun to sublime away. In summer, the dune field will be dark, as all of the frost will be gone and the iron- and magnesium-bearing silicate sands will be exposed.
Location near: 81.9°N, 226.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
8 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a field of dark sand dunes superposed on the light-toned floor of a crater in eastern Tyrrhena Terra. The orientation of the dunes -- with the steep faces toward the south (bottom) -- suggests that winds generally blew from north to south at the time the dunes were formed.
Location near: 14.6°S, 262.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Southern Summer
21 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a group of dust-covered buttes in the Aeolis region of Mars. Dozens of dark slope streaks -- created by dry avalanches of dust -- extend from a variety of elevations toward the base of each butte. Large, dust-covered, windblown ripples surround the group and occupy some of the low-lying areas between individual buttes.
Location near: 24.8°N, 114.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
7 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater approximately 2.5 kilometers (1.6 miles) in diameter located in Terra Cimmeria. Layered rocks and gullies are visible in the northern walls of the crater. A small patch of large, windblown ripples cover part of the crater floor.
Location near 32.8°S, 202.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
28 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a contact between a dust-covered plain and a dust-mantled, textured upland in the Memnonia Sulci region of Mars. The dominant landforms in this scene are yardangs-they are the product of extensive wind erosion of a relatively poorly-consolidated, sand-bearing material (e.g., deposits of volcanic ash or poorly cemented sedimentary rocks).
Location near: 9.3°S, 172.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
1 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes superposed on layered, light-toned outcrops -- interpreted to be sedimentary rocks -- in Melas Chasma. Melas Chasma is part of the enormous Valles Marineris trough system.
Location near: 11.7°S, 74.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
14 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows erosional remnants of layered rock and large windblown ripples on the floor of a crater in the Tyrrhena Terra region of Mars. The layered rocks are most likely sedimentary.
Location near: 68.5°N, 191.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
1 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers and possibly buried dunes in the north polar region.
Location near: 30 74.3°N, 264.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
Figure A
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Figure B
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Since their discovery early during the Mars Global Surveyor's Mars Orbiter Camera investigation, as first reported in June 2000, Martian gullies have presented a puzzle for the Mars science community: what fluid was responsible for the erosion that created the channels, and where did it come from? The gullies seem to be quite young in a geologic sense (millions of years or less), yet modern and geologically-recent Mars is an extremely dry place, where water ice sublimates directly to gas when the temperature is warm enough.
Since June 2000, many hypotheses have been discussed at scientific meetings, in the scientific journals and elsewhere. The original June 2000 hypothesis held that the fluid was liquid water (either pure, salty, acidic, etc.) that came to the surface where slopes intersected conduits of groundwater. Such slopes include crater walls, valley walls, hills, massifs and crater central peaks. Later investigators explored the possibility that rather than liquid groundwater, the source was ground ice, which, under some climate conditions, melted to produce liquid runoff. Still others noted that thick mantles covered a fraction of the gully-bearing slopes, suggesting that the mantles were ancient, dust-covered snow or ice packs that might melt at the base to make liquid water runoff. Water was not the only fluid considered by various colleagues; carbon dioxide can be fluid at some pressures and temperatures. Fluid carbon dioxide was also proposed as a candidate fluidizing agent. Even dry mass movement, or land sliding, of unconsolidated granular material can exhibit some fluid-like behavior. Such mass movements were considered as an explanation for the gullies.
The presence of channels primarily formed by erosion but also displaying features representing along-channel deposition, such as levees and meanders, and terminal depositional aprons consisting of dozens to hundreds of individual flow lobes, contributed to the general acceptance of the hypothesis that gullies involved the action of liquid water.
Throughout the Mars Global Surveyor mission, the Mars Orbiter Camera team continued to image gullies at every opportunity, looking for new gullies, taking higher resolution images of previously identified gullies, and monitoring the gullies for changes that might occur. Among the results of this extensive survey are numerous examples of gullies that have geological relations to other things in their vicinity. This provides support for the hypothesis that the fluid responsible for the gullies came from beneath the ground, either as groundwater or melting of ice in the Martian subsurface. Three of the best examples are presented here.
Figure A: The first picture shows a pair of gully channels that emerge, fully-born at nearly their full width, from beneath small overhangs on the north wall of Dao Vallis. These overhangs are probably created by the presence of a hard-rock layer. Liquid, probably water, percolated through permeable layers just beneath these harder, more resistant rock layers. The arrow points to the place where one of the two neighboring channels emerges. This is a sub-frame of an image acquired on Jan. 10, 2006, located near 34.2 degrees south latitude, 268.1 degrees west longitude. The 150-meter scale bar is about 164 yards wide.
Figure B: The second picture shows a gully that formed on the wall of a crater that intersected a mare-type ridge. The term, mare, is from the dark volcanic plains of Earth's moon, for example Mare Tranquilitatis was the plain on which the Apollo 11 crew landed in 1969. The lunar maria (maria is the plural form of mare), when viewed from above, have many "wrinkle" ridges. These ridges are the surface expression of thrust faults. The mare-type ridge in the picture shown here is thus the product of faulting, as rocks on the west (left) side of the image were thrust toward the east (right). Finding a gully associated with a fault is excellent evidence for the groundwater hypothesis, because ground water percolates through cracks and pores in the ground. On Earth, springs (where groundwater comes to the surface) are often found along fault lines. What is most important about this particular Martian gully is that it occurs equatorward of 30 degrees south, which is extremely unusual. The only gully in this crater is the one associated with the fault. It is essentially the site of a spring, now dried up perhaps. This picture is a sub-frame of an image located near 29.1 degrees south latitude, 207.5 degrees west longitude, acquired on Jan. 17, 2005.
Figure C: The third picture shows a small crater on the rim of a larger crater. Only a small portion of the wall of this larger crater is captured in the image. Immediately beneath the small crater occurs a group of gullies. The presence of these gullies also supports the groundwater hypothesis because impacting meteors will fracture the rocks into which they form a crater. In this case, there would be an initial set of subsurface fractures caused by the large impact that created the original, large crater. Then, when the smaller crater formed, it would have created additional fractures in its vicinity. These extra fractures would then have provided pathways, or conduits, through which ground water would come to the surface on the wall of the larger crater, thus creating the gullies observed. One might speculate that the group of gullies was formed by the impact that made the small crater, because of the heat and fracturing of rock during the impact process. However, the gullies are much younger than the small crater; the ejecta from the small crater has been largely eroded away or buried, and the crater partially filled, while the gullies appear sharp, crisp and fresh. This is a portion of an image located near 33.9 degrees south latitude, 160 degrees west longitude, acquired on March 31, 2006.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
Stretching along "Low Ridge" in front of the winter haven for NASA's Mars Exploration Rover Spirit are several continuous rock layers that make up the ridge. Some of these layers form fins that stick out from the other rocks in a way that suggests that they are resistant to erosion. Spirit is currently straddling one of these fin-like layers and can reach a small bit of light-toned material that might be a broken bit of it. Informally named "Halley," this rock was broken by Spirit's wheels when the rover drove over it.
Spirit's microscopic imager took this picture during the rover's 861st sol, or Martian day, of exploring Mars (June 5, 2006). The field of view is about 31 millimeters square (a square with sides of 1.2 inches). The light-toned soils in the bottom center and the top center of the image correspond to small, bright, bluish-white deposits just to the right of the rover's tracks in the lower left corner of an image from the panoramic camera (see PIA08567).
The first analyses of Halley showed it to be unusual in composition, containing a lot of the minor element zinc relative to the soil around it and having much of its iron tied up in the mineral hematite. When scientists again placed the scientific instruments on Spirit's robotic arm on a particularly bright-looking part of Halley, they found that the chemical composition of the bright spots was suggestive of a calcium sulfate mineral. Bright soils that Spirit has examined earlier in the mission contain iron sulfate.
This discovery raises new questions for the science team: Why is the sulfate mineralogy here different? Did Halley and the fin material form by water percolating through the layered rocks of Low Ridge? When did the chemical alteration of this rock occur? Spirit will continue to work on Halley and other light-toned materials along Low Ridge in the coming months to try to answer these questions.
29 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an undulating scene in the south polar region of Mars. Small, elevated mesas of smooth, relatively homogeneous-appearing material are separated by low-lying regions that are speckled and darkened in some local areas. Over the martian summer months, sublimation of solid carbon dioxide -- the bright material in the scene -- contributes to the darkening of the sides of the mesas as well as the low-lying regions between them.
Location near: 86.8°S, 341.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
12 September 2006
Mars Global Surveyor (MGS) has now been orbiting Mars for 9 years! It was the evening of 11 September 1997, Pacific Daylight time, but it was early in the morning on 12 September 1997, Greenwich Mean Time, when MGS fired its engines to slow down and drop into an elliptical orbit around Mars. The Mars Orbiter Camera (MOC) began acquiring its first images just a few days later.
Today, the MGS MOC remains extremely healthy and ready to begin its 10th year of operations. The dramatic MOC narrow angle camera image presented here was acquired in June 2006. It shows a crater that has been encroached by a field of dark, windblown sand dunes in the Syrtis Major volcanic region of Mars. The area downwind of the crater (to the left/lower left) is free of dunes because the raised rim of the crater prevented winds from causing sand to be deposited in the crater's lee.
Location near: 7.3°N, 292.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
12 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows defrosting south high latitude dunes. In late winter and into the spring season, dark spots commonly form on dunes and other surfaces as seasonal carbon dioxide begins to sublime away.
Location near: 59.3°S, 343.3°W
Image width: ~2 km (~1.2 mi)
Illumination from: upper left
Season: Southern Spring
28 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a chain of collapse pits on a dust-mantled, lava-covered plain northeast of Ascraeus Mons -- one of the giant volcanoes located in the Tharsis region of Mars. Pit chains are associated with collapse which may be driven by several processes including, but not limited to, crustal extension owing to tectonic processes and the collapse of the roof of a lava tube.
Location near: 14.8°N, 99.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
10 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dust devil traveling across a plain west-southwest of Schiaparelli Crater, in far eastern Sinus Meridiani. The dust devil is casting a shadow toward the northeast, just south (below) of an egg-shaped crater.
Location near: 6.4°S, 349.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Southern Summer
22 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the south polar residual cap. The darkened edges of the pits and mesas are evidence of the removal -- by sublimation -- of frozen carbon dioxide during the recent martian summer. Summer ended and autumn began in January 2006, shortly before this image was acquired.
Location near: 86.8°S, 90.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
20 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a layered slope in the martian north polar region, being exposed by the removal of an overlying, smoother material seen in the lower third of the image. At the time this picture was obtained, the entire area was covered by bright, carbon dioxide frost.
Location near: 79.7°N, 341.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
25 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows v-shaped troughs in the Hephaestus Fossae region of Mars. Light-toned, windblown ripples reside in the very lowest parts of the troughs, as well as on the cratered upland outside the troughs. Boulders and other types of debris, which were derived from the layered rock exposed near the top of the troughs, are seen resting on the trough floors and perched on the sloping trough walls.
Location near: 21.1°N, 236.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
13 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater in southern winter with frost deposits on the northern wall.
Location near: 37.5°S, 222.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
14 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows partially-filled collapse pits on the eastern flank of Alba Patera, a large volcano in northern Tharsis. The three pits near the bottom (south) of the image have collapsed to the point of coalescence, while the northern-most pit remains largely a separate entity.
Location near: 38.5°N, 103.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
This image from the Mars Orbiter Camera aboard NASA's Mars Global Surveyor spacecraft shows an overview of "Victoria Crater" and a portion of the area NASA's Mars Exploration Rover Opportunity has covered to reach the enormous depression.
Images such as this one from the Mars Orbiter Camera on NASA's Mars Global Surveyor are helping scientists and engineers decide the best path for NASA's Mars Exploration Rover Opportunity as it approaches "Victoria Crater."
In figure 1, a blue dot indicates "Cape Verde" and a red dot "Cabo Frio." These two points mark the extent of the crater visible from the rover's position on its 945th Martian day, or sol (Sept. 20, 2006), a location it had reached two sols earlier and from which much of this monster depression was still out of sight. The green annotations indicate "Duck Bay," a location expected to allow a view to the other side of the crater. A dune, or ripple, is to the left of the crater, right in front of the green dot location. This is where the team initially talked about sending Opportunity for the rover's first view down into the crater. After further consideration, the team opted for a drive to the right of that ripple (south of the green dot) near the rim.
The yellow lines that surround and intersect Victoria Crater are used to measure the crater and the distance to the far "bays." North is up. Victoria Crater is about 800 meters (half a mile) in diameter.
18 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the results of a small mass movement in a fretted terrain valley in the Coloe Fossae region of Mars (see upper right quarter of the image). The term, mass movement, is usually applied to landslides, although it is unclear in this case whether the landform resulted from a single, catastrophic landslide, or the slow creep of ice-rich debris.
Location near: 35.3°N, 303.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
15 June 2006
Galle Crater, not to be confused with the equatorial Gale Crater, is also known as "Happy Face Crater." A mound of layered rock -- in places over-ridden by dark sand dunes -- occurs immediately south of the "mouth" of Happy Face Crater. The mosaic of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) narrow angle images shown here reveals some of the details of a portion of the mound not covered by dunes. Groups of layers in the lowermost portion of this exposure cut across each other in several places. Each of these cross-cutting relations indicates a period during which the deposition of these layered materials -- interpreted to be sediment -- stopped and erosion took place instead. These periods of erosion were followed by new sedimentation -- new deposition of granular material. Unknown is whether these layers represent sediments deposited by wind or water; the cross bedding is reminiscent of the patterns of sand deposition in windblown dunes, but these features are larger than the textures and patterns commonly found in sand dunes. The picture is a mosaic of three MOC images, E22-01557, M14-02055, and R11-04138, each taken in a different martian year and at a different time of the year. The annotated figure (right) shows the location of a dust devil that was observed in the summertime image, R11-04138.
Location near: 52.3°S, 30.1°W
Image width: ~4 km (~2.5 mi)
Illumination from: upper left
Mosaic of MOC images: E22-01557, M14-02055, R11-04138
2 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers of bedrock exposed in the walls on both sides of an east-west-trending trough in the Memnonia/Mangala Valles region. Large boulders released from these rocky trough walls are found on the slopes and on the trough floor.
Location near: 18.4°S, 148.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
17 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a valley located at north middle-latitudes near Moreux Crater. This valley might once have been the conduit for a flowing liquid, such as water. Today, the valley is partially filled and the surrounding terrain has the characteristic "roughened" appearance common at middle latitudes in both martian hemispheres.
Location near: 40.7°N, 316.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
24 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies on the wall of a martian south mid-latitude impact crater. The channels in each gully head beneath an eroding overhang of layered rock, providing support for the hypothesis that some -- if not all -- martian gullies result from release of groundwater to the surface.
Location near: 33.0°S, 213.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
22 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of light-toned, massively-bedded rock in western Candor Chasma, part of the Valles Marineris trough system.
Location near: 5.5°S, 73.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
14 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned, layered rock outcrops in the central pit of an impact crater in the Thaumasia Planum region of Mars. The outcrops were tilted and broken-up by the extreme energy of the impact that formed the crater in which they occur. These are layers of rock that were brought up by the impact from horizontal beds that lie below the floor of the crater.
Location near: 21.7°S, 69.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
23 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned, layered, sedimentary rocks in a crater in the northwestern part of Schiaparelli basin. The repetition of these horizontal layers suggests the sediments could have been deposited in an ancient crater lake.
Location near: 0.3°S, 345.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
22 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes and relatively small, light-toned, windblown ripples on the floor of a crater in central Noachis Terra.
Location near: 50.0°S, 353.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
17 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a chain of pits on a lava- and dust-covered plain northwest of Tharsis Tholus -- one of the many volcanic constructs in the Tharsis region of Mars. Pit chains, such as this one, are associated with the collapse of surface materials into subsurface voids formed by faulting and expansion -- or extension -- of the bedrock.
Location near: 16.4°N, 92.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
24 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark dunes and light-toned sedimentary rock on the floor of Becquerel Crater.
Location near: 21.4°N, 8.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
11 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a nearly-filled impact crater on the northern plains.
Location near: 47.3°N, 294.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
12 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a group of impact craters in Aonia Planum, Mars. Remarkably, two of the craters are approximately equal in size, however, they clearly differ in age. The left (west) crater has a well-defined rim and its ejecta blanket overlies part of the less pronounced crater to its immediate east. The one with the ejecta blanket is younger. Other circular depressions in this bouldery scene are also old, eroded impact craters.
Location near: 59.5°S, 78.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
11 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies -- all of which head at the same level -- on a south mid-latitude crater wall. At the 6 meters (~20 feet) per pixel scale at which this image was obtained, the gullies almost appear as if they are the product of a "weeping layer," a porous layer of rock through which a liquid such as water may have percolated until it came to the martian surface at this crater wall, then flowed downslope, toward the crater floor.
Location near: 34.0°S, 208.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
Figure A
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Two Martian southern mid-latitude craters have new light-toned deposits that formed in gully settings during the course of the Mars Global Surveyor mission. Images from the Mars Orbiter Camera documented one case in an unnamed crater in Terra Sirenum, described in an accompanying release (see PIA09027 or MOC2-1618). The second case, in an unnamed crater in the Centauri Montes region, east of the Hellas Basin, is described here.
Gullies were first described by Mars Orbiter Camera scientists in June 2000, and many examples were presented in our June 2000 web releases and in a paper published in the journal Science. Additional examples of these middle and high-latitude landforms can be seen among the other more than 1,600 web releases.
The new gully deposit in an unnamed crater in the Centauri Montes region is located near 38.7 degrees south latitude, 263.3 degrees west longitude. Like the new gully deposit in Terra Sirenum, this one has a light tone relative to its surroundings. It is on an equator-facing slope on which numerous narrow gully channels occur. As this slope is always in sunlight during the afternoons when Mars Global Surveyor passes overhead, the gullies always appear somewhat "washed out," just as craters on a full Moon do when viewed from Earth with a telescope.
The new, light-toned flow was first noticed by the Mars Orbiter Camera science operations team in an image acquired on Sept. 10, 2005. Re-examination of other images of this crater showed that the new deposit had actually been present on Feb. 21, 2004, when the distal (down-slope) end of the deposit was captured in other images. In February 2004, the deposit had gone unnoticed because only a small portion of it was imaged. This location was first imaged by the Mars Orbiter Camera on Aug. 30, 1999. The deposit was not present at that time. Thus, it formed between Aug. 30, 1999 and Feb. 21, 2004.
Roughly 20 percent brighter than the surface as it appeared before the flow occurred, the new deposit exhibits characteristics consistent with transport and deposition of a fluid that behaved like liquid water and likely transported some fine-grained sediment along with it. The distal end of the flow broke into several branches, or digits, and the material diverted and flowed around low obstacles. As with the example in Terra Sirenum, the depth of the flow is too thin to be measured in 1.5-meter-per-pixel (1.7-yard-per-pixel) images, so a very small volume of liquid and sediment was involved. While the material flowed and easily budded into several branches, it also must have moved slow enough to not topple over some of the low obstacles in its path.
This picture is a colorized view of the light-toned gully deposit, draped over a topographic image derived from Mars Global Surveyor's Mars Orbiter Laser Altimeter data. The color comes from a table derived from the colors of Mars as seen by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment.
Figure A: This figure shows the southeast wall of the unnamed crater in the Centauri Montes region, as it appeared in August 1999, and later in September 2005. No light-toned deposit was present in August 1999, but appeared by February 2004. The 300-meter scale bar represents 328 yards.
Figure B: The second figure is a mosaic of several Mars Global Surveyor images, colorized using a table derived from Mars Reconnaissance Orbiter camera color data and overlain on a sub-frame of a Mars Odyssey Thermal Emission Imaging System image. The 1-kilometer scale bar represents about 0.62 miles.
Figure C: The third figure is a colorized view of the light-toned gully deposit as viewed from an oblique perspective, draped over topography derived from Mars Global Surveyor's Mars Orbiter Laser Altimeter data. The color comes from a table derived from the colors of Mars as seen by the Mars Reconnaissance Orbiter camera.
The new light-toned flow, by itself, does not prove that liquid water was involved in its genesis. However, this observation and the similar light-toned flow in Terra Sirenum together show that some gully sites are indeed changing today, providing tantalizing evidence there might be sources of liquid water beneath the surface of Mars right now. In both cases, these new flows may be indicating the locations of aquifers (subsurface rocks saturated with water) that could be detected by orbiting, ground-penetrating radar systems such as the Mars Express Mars Advanced Radar for Subsurface and Ionosphere Sounding or the Mars Reconnaissance Orbiter's Mars Shallow Subsurface Radar.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
23 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows small ridges in the Memnonia region of Mars. The ridges or yardangs, as they are called, are formed by wind erosion of a material which is apparently more susceptible to modification by wind than other, probably stronger, materials in the scene. The large circular feature is the site of a nearly-filled, nearly-buried meteor impact crater.
Location near: 3.4°S, 153.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Southern Summer
16 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered material in the walls of troughs in the Sirenum Fossae region. Also notice large windblown ripples and boulders on their floors.
Location near: 31.7°S, 151.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
1 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown ripples on the floor of Auqakuh Vallis. The light-toned area, running diagonally across the scene from the lower left (southwest) to the upper right (northeast), may be dust that has accumulated in the bottom of the valley and on top of the ripples.
Location near: 31.3°N, 299.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
5 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small, dust-mantled volcano on the plains east of the giant martian volcano, Pavonis Mons.
Location near: 1.6°S, 105.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Southern Spring
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Having realized that a new dark spot on Mars, seen in a red wide angle camera image acquired on 6 January 2006, might be an indication of a recent meteor impact site (see PIA09020 or MOC2-1611), the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) science operations team considered it possible to find more such impact sites using the MOC red wide angle camera. The most recent, freshest craters would be expected to be quite small, ranging from a few meters across to maybe a few hundred meters or so, at most, in diameter (100 meters is about 109 yards; compare that with a 100 yard U.S.-style football field). Something less than 100 meters across would not show up easily in a 240 meters per pixel red wide angle image. But the 6 January 2006 image showed that it could, because these small impacts, if they occur in an area thickly mantled with dust, will create a much larger "blast zone" around them.
Thus, the MOC science operations team set out to image a few of the dustiest regions on Mars -- Tharsis, Amazonis, and Arabia -- with the red wide angle camera. The same camera had, in May and early June 1999, already imaged most of the planet at about 240 meters per pixel scale. By repeating areas already imaged in May/June 1999 during the January/March 2006 timeframe, we would be able to identify more dark spots.
And, so, that is what we did. The Tharsis, Amazonis, and Arabia regions were re-imaged using the MOC red wide angle camera during January through March 2006. The data covered about 21,506,000 square kilometers (~8.3 million square miles; ~1/3 the surface area of Mars and more than twice the area of the United States). As each picture was received on Earth, we compared it with the images acquired during May/June 1999. Over the entire area surveyed, we found 39 dark spots that were present in early 2006 but not visible in May/June 1999.
The 39 dark spots, then, were the candidate impact sites. Each one of these became a target for the MOC narrow angle camera, which would be used to take an image of about 1.5 meters (4.9 feet) per pixel of each site. The targets were entered into the MOC database. Then, as the predicted MGS ground track came near each site, the MOC team targeted an image by working with the spacecraft engineers at Lockheed Martin Astronautics (Denver, Colorado) and the Caltech/Jet Propulsion Laboratory (JPL, Pasadena, California) to point the spacecraft and camera at each site using the Roll Only Targeted Observation (ROTO) maneuver.
Of the 39 dark spots, 20 turned out to be fresh impact sites, and 19 of them were not. The other 19 included mistaken identifications (one was a transient, large dust devil shadow; several were craters that had been present in earlier images but had changed in brightness owing to dust removal), new dark wind streaks, and new dark slope streaks created by avalanching dust on steep slopes.
Some of the 20 new impact sites received further attention, as the spacecraft and MOC were used to obtain cPROTO (compensated Pitch and Roll Targeted Observations) views that have a spatial resolution of 0.5 meters (1.6 feet) in the downtrack dimension and 1.5 meters (4.9 feet) in the cross track direction. The cPROTO views, where obtained, have a higher resolution and better signal-to-noise ratio than the original ROTO images.
Finally, while our approach of comparing MOC red wide angle camera images obtained in May/June 1999 with those obtained in January/March 2006 constrains the 20 craters all to having formed during the May 1999 to March 2006 time interval, we found in all cases that there were already other images that had been received on Earth that helped constrain the time of the impact more tightly. In some cases, the date of the impact could be pinned down to within a month or two, in other cases the interval covered several years. Data from the MGS MOC, Mars Odyssey Thermal Emission Imaging System (THEMIS), and Mars Express High Resolution Stereo Camera (HRSC) were all employed in the search.
Shown on this page (above) are pictures that illustrate our work to find new impact craters:
Figure A: This picture shows one of the new impact sites identified by the MOC team. Located in northern Arabia Terra near 29.3°N, 333.2°W, the actual crater is quite small, only 11.2 ± 3.0 meters in diameter. This is a sub-frame of MOC image S16-01105, acquired using a ROTO maneuver on 12 March 2006.
Figures B and C: These pictures are MOC red wide angle camera images, obtained at a scale of about 240 meters per pixel, of portions of Arabia Terra. Figure B is M01-01610 and was acquired during the MOC Geodesy Campaign (see PIA02022 and PIA02023, or MOC2-127) on 14 May 1999. Figure C, MOC S14-02741, was obtained on 26 January 2006 as part of the campaign to find new impact craters. By comparing the two images, one from 1999 and one from 2006, we were able to identify all new dark spots that formed during that interval. In this case, the new dark spot seen in the 2006 image, S14-02741, is inside the white circle. The same location is also indicated by a circle in the May 1999 image, but no dark spot is present there. In both cases, the white circle is about 12 km (7.5 mi) across.
Figure D: This map of Mars, showing the location of all the MOC red wide angle camera images acquired for the search for new craters during January through March 2006. These images cover most of Amazonis, Tharsis, and Arabia Terra. The base map is a product that combines the May/June 1999 MOC red wide angle data (plus later data for the south polar region) and laser altimeter data from MGS.
Figure E: This picture shows portions of two red wide angle camera context images that more tightly constrain when the new crater shown here (above, top, left) formed. The first picture, R05-00427, was acquired on 5 May 2003 and shows no dark spot at the site of the impact. The second picture, S05-01885, shows that the dark spot was present on 29 April 2005. Thus, these two images tell us that the impact occurred sometime between those dates: 5 May 2003 and 29 April 2005.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
9 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of rings on the martian northern plains. Each ring marks the location of a filled and buried (or, in some cases, mostly-filled and nearly-buried) impact crater. The dark spots on some of the rings are boulders -- or clusters of smaller rocks-associated with the buried craters.
Location near 68.7°N, 288.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
23 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a mesa and an impact grater just east of Phlegra Montes. The mesa is the eroded remnant of a once more extensive terrain. An apron of material surrounds the mesa.
Location near: 38.5°N, 193.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
1 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dusty terrain near the west rim of Malea Patera, located southwest of Hellas Planitia. The circular feature near the left (west) edge of the image is a filled and partially exhumed (and nearly inverted) impact crater which still shows a well-defined, raised rim. The dark streaks that run across the scene are tracks left by passing spring and summertime dust devils-a common occurrence in this area.
Location near: 63.4°S, 312.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
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These Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images show a young impact crater that formed in Arabia Terra near 22.2°N, 345.5°W, some time between 2 April 2001 and 11 December 2003.
This image and figure A are sub-frames of MOC image S16-01199, acquired on 13 March 2006. This image has been colorized using a look-up table derived from color data acquired by the Mars Reconnaissance Orbiter's High Resolution Stereo Camera (HRSC). The site features a crater about 24.0 ± 3.0 meters (about 79 feet) across. In other words, one can compare a 100 yard U.S. style football field with this 26 yards wide crater. The "blast zone" around the crater is much larger and includes combination of rays and chains of small secondary impacts.
Figure B: This picture shows how the timing of the impact event was constrained. The first picture is a sub-frame of MOC red wide angle image E03-00127, obtained on 2 April 2001. The white circle indicates the impact site. The second picture, obtained after the impact occurred, is MOC red wide angle camera image R12-01350, acquired on 11 December 2003.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
10 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two mesas on the northern plains of Mars. "Mesa" is the Spanish word for "table," and that is a very good description of the two elliptical features captured in this MOC image. In both cases, the mesa tops and the material beneath them, down to the level of the surrounding, rugged plain, are remnants of a once more extensive layer (or layers) of material that has been largely eroded away. The circular feature near the center of the larger mesa is the site of a filled and buried impact crater.
Location near: 53.5°N, 153.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
30 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a valley which has become partially-filled with material. It is located west of Hellas Planitia. The valley, entering the scene from the east (right), turns toward the southwest (lower left) and splits to form a "V." Partially-filled depressions are common throughout the scene, including the circular feature near the top of the image. In each such case, the filling material is probably the remains of a material that once covered the entire scene.
Location near: 48.4°S, 318.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
Voir l'image PIA08025: Partially-Filled Valley sur le site de la NASA.
3 June 2005
On 17 May 2005, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) acquired its 200,000th image since the spacecraft began orbiting Mars on 12 September 1997. This image shows details on the floor and in the ejecta blanket of a northern middle-latitude martian crater, was received on Earth the following day. Its red wide angle context frame was also acquired at the same time (see PIA07996).
This image marks a milestone for the Mars Global Surveyor mission, which has returned nearly four times the number of images of both the Viking 1 and Viking 2 orbiters, combined, in the late 1970s. An additional point of comparison, the two Viking camera systems returned about 70 Gbytes of data; MOC thus far has returned 365 Gbytes (after decompression).
The MOC is really a system consisting of three cameras: (1) a narrow angle camera, essentially a telescope, that obtains extremely high resolution views ranging from about 0.5 to about 14 meters per pixel; (2) a red wide angle camera that is used to take context images, daily global maps, and other selected images; and (3) a blue wide angle camera that also acquires daily global maps, views of the martian limb, and other selected targets. Both wide angle cameras can obtain images with resolutions in the range of 0.24 to 7.5 kilometers per pixel.
The first images acquired by MOC were taken during the third orbit of MGS on 15 September 1997. MGS conducted a pre-mission series of observations between mid-September 1997 and February 1999. Then, MGS conducted its 1 Mars year Primary Mission from March 1999 through January 2001. The Extended Mission phase for MGS began in February 2001 and continues to this day.
Location near: 32.7°N, 185.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Autumn
21 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an unconformity in an exposure of north polar layered material, at which older layers were cut-off and eroded before a new suite of layers was deposited above them. The terrain in the entire scene was covered by a thin frost of frozen carbon dioxide at the time this picture was acquired in June 2006.
Location near: 86.1°N, 208.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
24 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dust-mantled, layered remnants of sedimentary rock exposed by erosion on the floor of an unnamed crater located northeast of Crommelin Crater in Arabia Terra. Many of the low-lying areas separating the exposures are occupied by large, windblown ripples and, in some areas, by dark-toned, windblown sand.
Location near: 8.3°N, 7.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
14 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an unconformity in a sequence of layered material in the martian north polar region. MGS MOC has been examining many similar examples of unconformities created by erosion in the polar region this year. Long ago, the lower set of layers was deposited. Then, deposition ceased, and erosion occurred for some period. Then, the erosional period ended, and new layers were deposited. The older layers -- the ones deposited before the erosive event -- today appear truncated by the younger, more evenly-bedded layers. No one is certain what composes the north polar layers; they may be sequences of dust and ice.
Location near: 84.3°N, 235.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
The light-toned deposits that formed in two gully sites on Mars during the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) mission in the 1999 to 2005 period are considered to be the result of sediment transport by a fluid with the physical properties of liquid water. The young, light-toned gully deposits were found in a crater in Terra Sirenum (see PIA09027 or MOC2-1618) and in a crater east of the Hellas basin in the Centauri Montes region (see PIA09028 or MOC2-1619).
In their study of how the light-toned gully deposits may have formed, the MOC team considered their resemblance to light- and dark-toned slope streaks found elsewhere on Mars. Slope streaks are most commonly believed to have formed by downslope movement of extremely dry, very fine-grained dust, through processes thought by some to be analogous to terrestrial snow avalanche formation. Figure 1 shows the light-toned gully deposit in the crater in the Centauri Montes region, compared with typical slope streaks and several examples in which the slope streak gives a strong impression of having been produced by fluid-like flow.
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No AnnotationFigure 1. The fresh, light-toned gully deposits have some resemblance to slope streaks. (A) Light-toned gully deposit that formed between August 1999 and February 2004 in a crater in the Centauri Montes region of Mars. (B) Typical dark slope streaks, as seen in a valley in central Arabia Terra. Hundreds of MOC images have shown that the darkest streaks are the youngest; commonly, the darkest streaks are less than a few years old. (C) Dark slope streaks on a slope surrounding a pedestal crater in Tikhonravov Crater in Arabia Terra. These streaks, particularly the two near the center of the image, show evidence that the downslope movement of debris was diverted around obstacles, particularly large boulders. (D) Dark slope streaks, including some that diverted around obstacles, on knobs in the Aeolis region of Mars. The 300 meter scale bars are about 328 yards across; the 150 meter bar is 164 yards.
As shown in Figure 2, slope streaks can be lighter or darker than their surroundings. The majority of them are dark, and nearly always when light streaks are present, dark ones are nearby. This observation differs from the two light-toned gully deposits observed in Terra Sirenum and the Centauri Montes regions. In the case of the light-toned gully deposits, no dark slope streaks are present anywhere within the craters that they formed. As far as can we can tell, based on MGS MOC and Mars Odyssey Thermal Emission Imaging System (THEMIS) coverage, there are no dark slope streaks within hundreds of kilometers of the two gully deposits.
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No AnnotationFigure 2. Slope streaks of both light and dark tone, relative to their surrounding surfaces, in centralArabia Terra. Where light slope streaks are found, dark ones are almost always nearby. The500 meter scale bar is about 547 yards across.
Figure 3 shows that light and dark slope streaks occur in very specific regions (brown-shaded areas; particularly Tharsis, Amazonis, and near Elysium), and the gullies occur in different regions (pink-shaded areas; particularly middle northern and southern latitudes). In other words, the two fresh, light-toned gully deposits observed by MOC occur very far from the regions in which light and dark slope streaks are found. Indeed, the regions in which slope streaks occur are those that are most thickly covered with mantles of dust. Experience from driving the Sojourner and Mars Exploration Rover, Spirit, on dusty surfaces shows that when the uppermost coating of fine, bright dust is disturbed, the underlying surface is darker. Thus, dark slope streaks are considered to be areas where dust has been disturbed and slid downhill by dry, granular flow. The dust is extremely fine, like the flour used to bake bread.
Figure 3
Annotated ImageFigure 3. This map of Mars shows areas where gullies occur, shaded in pink, and where light and dark slope streaks occur, shaded in brown. The location of the two craters in which MGS MOC observed new, light-toned gully deposits are indicated. Except for a small portion of Tempe Terra (northeast of Tharsis), gullies and slope streaks do not occur together in the same regions. Slope streaks occur in regions that have been known since the Viking orbiter missions to be thickly mantled with dust. Gullies occur at middle and high latitudes, where dust mantles are not so thick. The pink-shaded gully area is based upon the MOC team's survey of over 96,000 MOC narrow angle camera images. The brown-shaded area, representing light and dark slope streak occurrences, comes from a combination of the MOC team's assessment and the published results of O. Aharonson, N. Schorghofer, and M. F. Gerstell (2003) Slope streak formation and dust deposition rates on Mars, Journal of Geophysical Research, v. 108, no. E12, doi:10.1029/2003JE002123.
New dark slope streaks are forming on Mars all the time. MGS MOC images have captured hundreds of before-and-after examples. Figure 4 shows one site that MOC monitored in the Elysium/Cerberus region.
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No AnnotationFigure 4. The MOC narrow angle camera has acquired hundreds of images that repeat locations where slope streaks occur. In so doing, MOC captured hundreds of cases where new slope streaks formed. New streaks are always dark, not light. Several examples on hillslopes in the Elysium/Cerberus region are shown here, spanning a period from April 1998 through January 2005. The 300 meter scale bar equals about 328 yards.
New slopes streaks are always dark. No new light slope streaks have been observed by MOC, despite monitoring over the past 7-9 years at dozens of locations. Figure 5 shows one such example on the wall of Bahram Vallis, in which a suite of light slope streaks remained unchanged over a period spanning September 2000 through December 2005.
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No AnnotationFigure 5. Light slope streaks are more rare than dark slope streaks. Curious as to whether new light streaks form under present conditions, just as new dark streaks do, the MOC team monitored dozens of light slope streak sites. But no new light slope streaks have been observed. This time series includes images from 2000, 2003, and 2005; no new streaks formed during this period. The 400 meter scale bar is about 437 yards across.
Not only have no new light slope streaks been observed, dark streaks have been seen to superpose (i.e., formed or were deposited on top of) light streaks. Figure 6a shows a case where several dark streaks are superimposed on several light streaks. Figure 6b shows a before-and-after example, in which a new dark streak wiped out underlying, older light slope streaks.
Figure 6A
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No AnnotationFigure 6. MOC images show that dark slope streaks always superpose light slope streaks, never the other way around. This observation reinforces the view that light slope streaks are not formed by the downslope movement of dust -- when dust moves, it creates a dark streak. Light streaks might therefore be old dark streaks, perhaps trapping light-toned dust better than the adjacent, intermediate-toned slopes. (A) Light and dark slope streaks on the wall of an unnamed valley in central Arabia Terra. Dark streaks in some cases superpose light streaks. (B) Light and dark slope streaks in Arabia Terra in an example where a new, large dark streak formed sometime between January 2001 and August 2003. The new dark streak formed on top of older light slope streaks. The 500 meter scale bars are about 547 yards across.
The MGS MOC team's experience, gained from examining all of the more than 96,000 MOC narrow angle camera images -- and seeking evidence for changes among gullies, slope streaks, and other variable features on the planet's surface -- is that slope streaks form on very dusty slopes, the newest ones are dark, and older ones lighten with time as new dust is deposited on them. The origin of light slope streaks is not known, although we suspect they are related to dark slope streaks. Dark slope streaks may be dark because they have lost their light dust cover or because disturbed surfaces often have micro-relief that casts miniature shadows on the surface. Slope streaks that are lighter than their surroundings may have trapped newly-fallen dust within this microrelief, and may do so more effectively than adjacent, smooth slopes.
Slope streaks have attributes that indicate they experienced fluidized motion, but the fluid was less viscous (more fluid) than water-lubricated dirt. As with snow avalanches, the "fluid" was probably atmospheric gas ingested and intimately mixed with the dust as it began and continued to move downslope. Such air-fluidized flows stop more abruptly than do water-fluidized flows on comparable slopes.
In developing geologic interpretations from inspection of images, many factors are considered: size, relief, shape and pattern, color or brightness, texture, and association (context). Context is often the final discriminator between features that look similar. It is undeniable that the gully deposits resemble slope streaks, but they do not share the same context. If they are slopes streaks formed by downslope movement of dry, unconsolidated dust, then they are extremely rare features, because the new gully deposits (a) do not occur in regions where slope streaks occur, (b) are not found near any dark slope streaks, while typical light slope streaks have dark ones nearby, and (c) formed during the MGS MOC mission, while no new light slope streaks were observed to have formed anywhere else on the planet during the mission. Conversely, their presence within craters with gullies and the existence of similar light-toned features on other gullied (and in some cases on adjacent) slopes, with which they share geomorphic attributes, may be coincidental but is probably not. The gullies themselves provide the context for the gully deposits, and argue for a genetic relationship.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
28 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a plain southeast of Hebrus Valles that is cut by a network of intersecting troughs. Large, windblown -- and perhaps wind-eroded -- ripples occur on the trough floors.
Location near: 14.9°N, 229.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
26 May 2005
This picture is a mosaic of two Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images of sedimentary rock outcrops in Aram Chaos, near Ares Vallis, Mars. Aram Chaos is an impact crater that was nearly completely filled with material, some of which is light-toned, layered, sedimentary rock. The MGS Thermal Emission Spectrometer team detected crystalline hematite in Aram Chaos, attesting to its potential similarity to some of the rocks in Meridiani Planum, where the Mars Exploration Rover (MER-B), Opportunity, has been operating. During April 2005, an opportunity arose to acquire a MOC narrow angle camera image that would mosaic with a previous picture, R11-02268. The figure shown here is a mosaic of that earlier image, obtained in November 2003, and the newer picture, from April 2005. Sunlight illuminates the scene from the right, and north is toward the bottom. A steep slope is seen near the top of the image. It formed in light-toned sedimentary rock, and it has shed debris to form a suite of darker-toned talus deposits. These deposits are the products of dry mass movement; the darker tone of the debris might be an indication that the material is less weathered or coarse-grained. Evident below the scarp are several light-toned yardangs, sculpted by wind. Erosion of the yardang-forming material, interpreted to be sedimentary rock, has revealed dark-toned blocks, separated by troughs. The blocks pre-date the deposition of the yardang-forming material. The presence of these broken-up blocks suggests that a chaotic terrain pattern formed in Aram>text missing position of material that later became the light-toned, sedimentary rock. The geologic history recorded in Aram Chaos is no less complex than has been observed by MOC in other large craters, such as Gale.
27 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes on the floor of an impact crater west of Hellas Planitia. Portions of the crater floor are exposed near the center and lower right corner of the image but, in general, the floor is covered by large, windblown ripples. The dark dune sand typically covers ripples, indicating that the dunes are younger and made of a more mobile material.
Location near: 43.7°S, 320.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
6 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the termination (end) of a group of layers in the north polar region of Mars, where they have been buried by younger, smoother-surfaced material. The layers are the banded features at the right/lower right. They are emerging by erosion from beneath the smoother material that dominates the scene. As the smooth material erodes, its margins become rough and rugged. No one knows the composition of the layered materials of the north polar region; most believe that they are a mixture of various proportions of ice, dust, and in some places, sand.
Location near: 81.3°N, 293.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
29 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows buttes and mesas surrounded by sand dunes on the floor of Rabe Crater, Mars. Gullies of uncertain origin cut sand dune surfaces in the top (north) quarter of the scene.
Location near: 44.1°S, 325.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
30 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a variety of materials found on the floor of an impact crater northwest of Hellas Planitia. The discontinuous, dark-toned ridges, typically running diagonally across the scene, are windblown ripples which overlie light-toned rock that is heavily fractured and cratered.
Location near: 25.0°S, 322.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
13 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows erosional remnants of layered rock and large windblown ripples on the floor of a crater in the Tyrrhena Terra region of Mars. The layered rocks are most likely sedimentary.
Location near: 15.5°S, 270.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
2 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows impact craters and wind streaks in Daedalia Planum.
Location near: 14.6°S, 131.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
5 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows blocky remnants of a material that was once more laterally extensive on the floor of an impact crater located northwest of Herschel Crater on Mars. Large ripples of windblown sediment have accumulated around and between the blocks.
Location near: 8.6°S, 236.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
7 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows wind-eroded outcrops overlying lava flow surfaces located west of Olympus Mons. Outcrops with this appearance are called yardangs. Yardangs typically form in sedimentary rock or volcanic ash that contains some amount of sand. The weathering of the rock and release of sand-sized particles from the outcrops, in the face of wind erosion, slowly shape the rock into the classic, inverted boat hull-like shapes of yardangs.
Location near: 13.2°N, 160.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
7 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the walls and floor of an old impact crater in northeastern Tempe Terra.
Location near: 46.2°N, 59.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
9 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an eroded stack of layered material in a crater of the south polar region of Mars. The composition of the layers is not known; some speculate that they may contain a combination of dust and ice, or possibly ancient sedimentary rock.
Location near: 80.6°S, 230.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
20 September 2006
When it was launched in 1996, the plan was that Mars Global Surveyor (MGS) would wrap up its mission in 2000. Damage to a hinge connected to a solar panel slowed the orbit insertion aerobraking process by a year, so in 1997 the spacecraft team determined that MGS's mission would end in early 2001. However, the spacecraft and its instruments remained healthy, and its mission was extended. And extended. And extended again. And again. MGS has now been orbiting the red planet for just over nine years. Throughout the mission, data from the Mars Orbiter Camera (MOC) have emphasized details about some of the very oldest and the very newest features exposed on the planet's surface.
The very ancient and the modern come together in this small, approximately 3 km by 3 km (1.9 mi by 1.9 mi) area on the floor of an unnamed impact crater in western Arabia Terra.
Old are the light-toned, layered mounds scattered across the image. The layers form stair-steps leading to the top of each mound. In most cases, the 'steps' are not clean, but are instead covered with debris eroded from the next layer, or step, above. The mounds are remnants of layered rock that once covered the entire scene. They were deposited as sediment in the large, unnamed crater in which these landforms occur. Their regular thickness and repeated character suggest that episodic, or perhaps cyclic, processes brought sediment to the crater floor. If the crater contained water at the time the sediments were deposited, then they represent lakebed materials. The processes that (a) brought sediment to this site, (b) cemented the sediment to form rock, and (c) eroded the sediment to form the mounds we see today, all occurred at some time in the distant past.
New are the dark-toned sand dunes and intermediate-toned ripples. The dark dunes were formed of sand that in relatively recent times has been blown by wind from the northeast (upper right) toward the southwest (lower left). The dunes have slowly encroached upon the older, light-toned, layered mounds. Surrounding each mound is a suite of intermediate-toned ripples. These are large ripples, relative to counterparts on Earth, and are most likely made up of grains somewhat coarser than sand, typically of several millimeters in size. The ripples form a pattern that is generally radial to each mound, indicating that they formed in winds that interacted with these topographic obstacles. The dark dunes are generally younger than the ripples, as dark sand has encroached upon and over-ridden some of the ripples.
This image is one of the favorites of the MOC operations team at Malin Space Science Systems, because it is not only pretty, it also emphasizes aspects of both the ancient and modern sedimentary processes and materials on Mars. Sediments, sedimentary rocks, and the environments in which they were deposited have been a key theme of the MOC science investigation from the beginning, more than 20 years ago, when MOC was selected by NASA to be built and sent to Mars. The first MOC was aboard Mars Observer when it was lost in 1993; the second MOC was built for MGS and is still operating today.
Location near: 8.8°N, 1.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
8 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows craters with wind streaks in Acidalia Planitia. The winds responsible for the streaks blew from the upper right (northeast).
Location near: 37.1°N, 36.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
22 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a dust-covered plain northwest of Jovis Tholus which is host to several overlapping, ancient lava flows and a channel containing streamlined features indicative of fluid flow.
Location near: 22.5°N, 122.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
7 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows repeated layers of material, possibly a combination of dust and ice, or perhaps ancient sedimentary rock, exposed by erosion on a slope in the south polar region of Mars.
Location near: 83.9°S, 257.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
21 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark north polar dunes overlying other materials in the north polar region.
Location near: 79.1°N, 228.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
2 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater on the martian northern plains. This crater is roughly the size of the famous Meteor Crater in Arizona on the North American continent.
Location near: 43.0°N, 231.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
23 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a favorite among the MGS MOC operations team at Malin Space Science Systems, another example of the grooved dunes in Herschel Crater. The fine-scale grooves on the sand dune surfaces were formed by wind erosion. The sand dune surfaces have, over time, become crusted and the dunes immobilized. Wind now has to scour sand from the surfaces of these bedforms, creating small wind erosion features known as yardangs in the sand.
Location near: 15.7°S, 228.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
10 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cone-shaped hill, perhaps a remnant of a material that was once more laterally extensive across the area, on a textured plain in the Hyperboreus Labyrinthus region in the north polar region of Mars. The hill and its surroundings are covered with a blanket of solid carbon dioxide which imparts a roughly homogeneous-tone to the scene. Despite its shape, the feature is not a volcano; over the past 9 years, the MGS MOC investigation has found no unambiguous evidence for volcanic landforms in the north polar region.
Location near: 79.5°N, 57.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
26 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the stair-stepped, north wall of a crater in Arabia Terra. Light-toned slope streaks have formed as a result of avalanches in the dry, dark dust that mantles both the crater and its adjacent terrain in this scene.
Location near: 20.0°N, 324.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
20 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows remnants of layered materials near the west rim of South Crater, Mars. The composition of these layered rocks is unknown -- are they the remains of sedimentary rocks or accumulations of dust and ice? We'll probably not know until someone visits this area, perhaps centuries from now.
Location near: 77.4°S, 341.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
28 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.5 meters per pixel (5 ft/pixel) view of a ~1 km wide crater. Boulders ejected by the impact that formed the crater can be seen in the ejecta blanket.
Location near: 34.1°N, 247.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
4 August 2006
This This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a bowl-shaped crater on the martian northern plains with a mysterious radiant pattern of zones with and without boulders and rocks. The rocky areas are seen as dark dots, the rock-free areas lack these spots. Craters like this are fairly common on the northern plains; some also occur at a similar latitudes in the southern hemisphere. When the Mars Odyssey Thermal Emission Imaging System (THEMIS) team first saw these, earlier this decade, they called them"pinwheel craters" (see PIA05611). The exact cause of the boulder and streak distribution is uncertain.
Location near: 61.3°N, 88.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
18 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a narrow channel on the upper east flank of the martian volcano, Hadriaca Patera. Because it is located on a volcano, most likely this channel was formed by lava, perhaps as a lava tube at which the thin roof later collapsed. Large ripples of windblown sediment now occur on the channel floor; their crests are generally perpendicular to the channel walls, suggesting that winds blow up and down through this channel.
Location near: 30.5°S, 266.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
19 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of light-toned rock, interpreted to be sedimentary in origin, in east Candor Chasma. The exposures of light-toned rock are separated by areas of windblown ripples and dark sand.
Location near: 8.2°S, 64.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
27 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered material of the north polar region.
Location near: 84.6°N, 225.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
22 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows yardangs formed by wind erosion of materials exposed on the floor of western Tithonium Chasma. The winds responsible for these landforms blew from the north/northeast (top/upper right). Tithonium Chasma is part of the Valles Marineris system.
Location near: 4.8°S, 89.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
24 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a large and several small pits formed by collapse along the trend of a fault system in the Uranius Fossae region of Mars. Running diagonal from middle-right toward lower left is a trough that intersects the pit. The trough is a typical graben formed by faulting as the upper crust of Mars split and pulled apart at this location. The opening of the graben also led to formation of the collapse pits.
Location near: 26.2°N, 88.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
17 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a modest-sized meteor impact crater in the Elysium Planitia region of Mars. The dark spot inside the crater is, most likely, a patch of windblown sand and silt. This crater is nearly twice the size of the famous Meteor Crater in northern Arizona in North America.
Location near: 31.8°N, 243.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
27 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an array of gullies in the north-northwest wall of a crater in Terra Cimmeria. These features may have been formed through the interaction of several processes including, but not limited to, mass wasting and/or seepage and runoff of groundwater.
Location near: 33.5°S, 207.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
22 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a valley, possibly formed by collapse, in the Ceraunius Fossae region of northern Tharsis.
Location near: 22.3°N, 109.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
This image from the Mars Orbiter Camera aboard NASA's Mars Global Surveyor highlights the Mars Exploration Rover Opportunity's approach toward "Beagle Crater."
North is to the left. Opportunity's locations at sols 804 (April 29, 2006) and 855 (June 20, 2006) are marked, as are the left and right edges of the rim of "Victoria Crater" from the rover's point of view. The labeled "promontory" is a bright spot that scientists originally thought was an outcrop on the far side of the crater, based on the single azimuth measurement on sol 804 (see PIA08447). But comparing the azimuth angle of this feature in the sol 855 panorama and the angle of the same feature in the sol 804 panoramic image (a process known as triangulation) revealed that this outcrop must instead be on the near rim of the crater. Marked in salmon are two small craters beyond Beagle crater that are on the dark "annulus," or ring, around Victoria Crater.
Victoria Crater is 730 meters to 750 meters (nearly half a mile) in diameter, about six times wider than "Endurance Crater," where Opportunity spent several months in 2004 examining rock layers affected by ancient water.
This image is an uncalibrated version that the rover team uses for planning. It has been reprojected and stretched in some places and isn't used for scientific purposes.
11 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows streamlined landforms carved by catastrophic floods in the Athabasca Valles system of the Cerberus region of Mars.
Location near: 7.9°N, 205.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Autumn
25 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a high resolution view of the floor and walls of a trough located west of the Elysium Mons volcano. The trough cuts through layered and dust-mantled rock. Large boulders and windblown ripples, mostly covered with a blanket of dust, can be seen on the trough floor.
Location near: 21.2°N, 222.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
14 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes, with a thin coating of autumn frost, in the Ogygis Regio west of Argyre basin. The steepest slopes on the dunes, their slip faces, point toward the north-northeast (upper right), indicating that the dominant winds in the region blow from the south-southwest (lower left).
Location near: 50.4°S, 66.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
14 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a circular mesa that is the remains of an old crater bottom. The crater was mostly washed away by floods that poured from the southeast (lower right) toward the northwest (upper left) in the Mangala Valles system.
Location near: 16.4°S, 150.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Spring
North is to the left. Opportunity's location at sol 804 (April 29, 2006) is marked, as are the left and right edges of Victoria's rim from the rover's point of view. The labeled "promontory" is a bright spot that scientists believe is an outcrop on the far side of the crater. Marked in light purple is a small, 35-meter (115-foot) crater.
Victoria Crater is 750 meters (nearly half a mile) in diameter, about six times wider than "Endurance Crater," where Opportunity spent several months in 2004 examining rock layers affected by ancient water.
This image is an uncalibrated version that the rover team uses for planning. It has been reprojected and stretched in some places and isn't used for scientific purposes.
29 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned, layered, sedimentary rock outcrops in northwest Schiaparelli Basin. The layers are all of about the same thickness (a few meters or less) and appear to have similar properties. They were likely deposited in an episodic or cyclic manner, perhaps in an underwater setting.
Location near: 1.2°S, 346.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
3 June 2005
On 17 May 2005, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) acquired its 200,000th image since the spacecraft began orbiting Mars on 12 September 1997. This red wide angle context frame was acquired at the same time as the narrow angle image (see PIA07995 showing details on the floor and in the ejecta blanket of a northern middle-latitude martian crater, which was received on Earth the previous day).
This image marks a milestone for the Mars Global Surveyor mission, which has returned nearly four times the number of images of both the Viking 1 and Viking 2 orbiters, combined, in the late 1970s. An additional point of comparison, the two Viking camera systems returned about 70 Gbytes of data; MOC thus far has returned 365 Gbytes (after decompression).
The MOC is really a system consisting of three cameras: (1) a narrow angle camera, essentially a telescope, that obtains extremely high resolution views ranging from about 0.5 to about 14 meters per pixel; (2) a red wide angle camera that is used to take context images, daily global maps, and other selected images; and (3) a blue wide angle camera that also acquires daily global maps, views of the martian limb, and other selected targets. Both wide angle cameras can obtain images with resolutions in the range of 0.24 to 7.5 kilometers per pixel.
The first images acquired by MOC were taken during the third orbit of MGS on 15 September 1997. MGS conducted a pre-mission series of observations between mid-September 1997 and February 1999. Then, MGS conducted its 1 Mars year Primary Mission from March 1999 through January 2001. The Extended Mission phase for MGS began in February 2001 and continues to this day.
Location near: 32.7°N, 185.1°W
Image width: ~115 km (~71 mi)
Illumination from: lower left
Season: Northern Autumn
17 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a bright plain west of Schiaparelli Crater, Mars, which is host to several features, some of them long-lived and others that are transient. The circular features scattered somewhat randomly throughout the scene are impact craters, all of which are in a variety of states of degradation. In the lower left (southwest) corner of the image, there is a small hill surrounded by ripples of windblown sediment, and near the center of the image, there is an active dust devil casting a shadow to the east as it makes its way across the plain.
Location near: 5.9°S, 348.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
18 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a ring marking the location of a nearly-filled, nearly-buried impact crater on the martian northern plains. Remnants of bright, seasonal frost occur in some polygonal cracks on the plain.
Location near: 62.9°N, 96.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
26 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-toned sand dunes on the floor of Russell Crater in south-central, Noachis Terra. A dune at the right (east) edge of the image is host to several small gullies whose channels extend predominantly to the west-southwest. The formation of these features is not well-understood, but they might result from a combination of downslope movement of sand and a lubricating agent, perhaps carbon dioxide gas or water that had been trapped in the dune as ice. The randomly-oriented dark streaks seen on the dunes and on the interdune surfaces were created by the passage of spring and summertime dust devils.
Location near: 54.7°S, 347.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
1 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two impact craters of nearly equal size, plus their associated wind streaks. These occur in far eastern Chryse Planitia. The wind streaks point toward the southwest (lower left), indicating that the responsible winds blew from the northeast. One of the two craters is shallower than the other, and has a suite of large, windblown ripples on its floor. The shallower crater with the ripples is probably older than the other, deeper crater.
Location near: 20.6°N, 30.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
16 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows cross-cutting fault scarps among graben features in northern Tempe Terra. Graben form in regions where the crust of the planet has been extended; such features are common in the regions surrounding the vast "Tharsis Bulge" on Mars.
Location near: 43.7°N, 90.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
15 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows remnants -- buttes and knobs -- of light-toned rock, perhaps sedimentary in origin, on the floor of Rabe Crater. The buttes and knobs are surrounded by dark, windblown sands that are crisscrossed dust devil tracks.
Location near: 44.0°S, 325.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
4 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered, light-toned, sedimentary rocks that have been exposed by erosion in Coprates Chasma, one of the many chasms which comprise the Valles Marineris trough system on Mars.
Location near: 13.1°S, 65.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
6 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-toned sand dunes on the floor of Stokes Crater, located on the martian northern plains. The steepest slopes on the dunes indicate the direction of sand transport; the winds responsible for these dunes generally blow from the north/northeast (top/upper right).
Location near: 55.9°N, 188.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
6 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak created in the lee -- the downwind side -- of a crater in far eastern Chryse Planitia. The winds responsible for the formation of the streak blew from the upper right (northeast) to the lower left (southwest).
Location near: 21.5°N, 27.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
20 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a complex pattern of intersecting and overlapping troughs in the Olympica Fossae region of northern Tharsis. Some combination of floods, lava flows, and faulting/tectonic activity contributed to this scene, followed by mantling by dust. Dark streaks on slopes in the troughs were formed by dust avalanches.
Location near: 24.8°N, 114.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
2 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygonal cracks formed in the material that nearly fills an impact crater on the martian northern plains. The light-toned patches in the cracks are the remains of ice, left over from the preceding winter. On Earth, polygons such as these are most common in the polar regions, and form in the presence of ground ice. Whether the same is true for Mars remains to be determined, but, certainly, this is a good possibility.
Location near: 65.7°N, 277.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
3 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a relatively flat plain in Acidalia Planitia. The circular feature near the left (west) edge is the surface manifestation of a buried impact crater, a common feature observed on the northern plains of Mars. The darker feature is a younger, fresher impact crater -- but, it too, has been somewhat buried beneath a mantle of material.
Location near: 53.1°N, 32.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
19 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a contact between terrain which is completely mantled by a smooth-surfaced material -- perhaps dust -- and a rugged, cratered surface that is only partially dust-covered in the Noachis Terra region of Mars. The smooth-surfaced material likely once covered this entire scene, but has been slowly eroded away to reveal the underlying, older surface.
Location near: 27.8°S, 338.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
12 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows terrain southwest of Meroe Patera in Syrtis Major Planum, Mars. Wind streaks formed in the lee -- i.e., the downwind side -- of impact craters are common throughout the scene, including the small impact crater near the center of the image with light-toned ejecta radiating outward from its rim. Near the bottom (south) of the image, three light-toned slope streaks, created by dry mass movements of dust, extend down the sloping side walls of two overlapping impact craters.
Location near: 5.3°N, 295.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
3 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows buttes and two eroded impact craters on the plains west of Sinus Meridiani. The buttes and bedrock here are composed of light-toned, layered, sedimentary rock similar to the bedrock at the Mars Exploration Rover, Opportunity, site. The layers can be seen in the walls of the two large, dark-floored craters.
Location near: 0.5°N, 8.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
28 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers exposed in a trough in the martian north polar region. At the time the picture was acquired, the entire scene was covered by seasonal carbon dioxide frost. By late spring and into summer, these layers would appear darker, once the carbon dioxide frost sublimes away.
Location near: 84.9°N, 263.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
28 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a steep slope in the north polar region of Mars. The stripes indicate an exposure of layered material; the variations in brightness among the stripes are the result of varying amounts and textures on seasonal carbon dioxide frost. At the time the image was acquired in June 2006, the carbon dioxide frost was beginning to sublime way, leaving a variety of different patterns in frost distribution.
Location near: 85.2°N, 122.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
30 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a pedestal crater in the Eumenides Dorsum region of Mars. The rocky ejecta from this crater protected the underlying material from being eroded away by wind, leaving the crater standing high above the surrounding plains.
Location near: 11.9°N, 156.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
9 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small portion of a dust-covered plain directly north of Labyrinthus Noctis which is cut by three linear troughs. The two long troughs running diagonally from the lower left (southwest) to the upper right (northeast) are connected by a third, shorter trough. Boulders derived from erosion of layered rock in the trough walls are seen perched on the sloping sidewalls and resting on the trough floors among giant windblown ripples.
Location near: 0.2°N, 105.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
29 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a field of dark sand dunes in an unnamed crater in the Noachis Terra/Hellespontus region of Mars. In southern autumn, the skies are generally clear and the sun comes in at a steep enough angle that martian dunes look especially striking.
Location near: 43.6°S, 320.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
1 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes in the martian north polar region. The dunes are composed of dark, coarse sand. The white areas around the dunes are the last remaining areas of seasonal carbon dioxide frost cover. The solid carbon dioxide accumulates during the autumn and winter and sublimes (goes from solid to gas) away in the spring. This image was taken near the end of the northern spring.
Location near: 78.0°N, 244.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
20 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind ripple-filled trough, a fracture in a rugged and pitted plain, located northwest of Kasei Valles in the Nilus Chaos region.
Location near: 26.3°N, 78.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
29 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small mountain in the Lycus Sulci region, northwest of the Olympus Mons volcano. Dark streaks, probably caused by avalanching and flow of extremely dry dust, have formed on the mountain's slopes. The various ridged and grooved textures in this scene were formed by wind erosion.
Location near: 22.6°N, 145.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
17 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows rugged terrain in the northern plains. The circular features are old, buried impact craters. The bright spots are small patches of the seasonal frost that has been almost entirely removed from the area by sublimation (turning from solid to gas).
Location near: 70.7°N, 271.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
23 May 2005
These two Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images were acquired a little more than four Mars years apart. One Mars year is about 687 Earth days long. The two images show a portion of the south polar cap, which is composed of frozen, layered, carbon dioxide. Each Mars year since MGS has been observing the planet, the mesas and buttes composed of carbon dioxide have gotten a little bit smaller, and the pits and holes have become a little bit wider. The scarps formed in frozen carbon dioxide in the south polar region are retreating at an average rate of about 3 meters per Mars year. The example shown here includes an image obtained in August 1999, and a more recent picture from April 2005. Arrow "1" points to a dramatic example of the changes that have occurred; in this case a mesa shrank to a small butte in just four martian years. Arrow "2" indicates pits that developed in the cap layer of a carbon dioxide mesa that eroded during the same interval. Acquired during early southern spring, both images are illuminated by sunlight from the upper left.
29 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies and cracked and stressed gully apron deposits in a south mid-latitude crater. Gullies can also be seen in the deep shadow on the north wall of the crater. These gullies might have formed by the erosive action of liquid water, sometime in the not-too-distant martian past.
Location near: 36.7°S, 206.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
27 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a high resolution view of a surface composed almost entirely of eroded, exposed sedimentary rock in the Sinus Meridiani region of Mars. If one could vacuum up all of the dark sand and dust that covers the rocks at the Mars Exploration Rover, Opportunity, site, one might find a surface similar to that shown here. Note, just right of center, the occurrence of a circular feature. This is the site of a filled and buried meteor impact crater. Filled and buried craters are common among the sedimentary rocks of the Meridiani region.
Location near: 1.5°N, 359.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
This is the first image of Mars taken by the Context Camera on NASA's Mars Reconnaissance Orbiter. The spacecraft began orbiting the red planet on March 10, 2006. During its 10th close approach to Mars, on March 24, it turned its cameras to view the planet's surface. Although the images acquired were about 10 times lower in resolution than will ultimately be obtained when the spacecraft has finished reshaping its orbit for the mission's primary science phase, these test images provide important confirmation of the performance of the cameras and the spacecraft.
This first image by the Context Camera includes some chaotic terrain at the east end of Mars' Valles Marineris, seen along the top (northern) edge of the image. The image has a scale of about 87 meters (285 feet) per pixel, which is 14.5 times lower resolution than will be acquired during the primary science phase. Typical images from the Context Camera acquired during that phase of the mission will have a resolution of 6 meters (20 feet) per pixel, and will cover an area about 30 kilometers (18.6 miles) wide.
Note that, because these are initial, test images, there is some linear striping in the images. This results from incomplete removal of pixel-to-pixel variations in the Context Camera detector by the present calibration software. One use of the test imaging is an opportunity to fine-tune the calibrations before the primary science phase begins.
Figure 1 is a comparison of a wide-angle, red-filter image from the Mars Orbiter Camera on NASA's Mars Global Surveyor (left) with the first Mars image from the Context Camera. The image from the Mars Orbiter Camera was taken the same day, but about 6.2 hours after the image from the Context Camera, at a local solar time of 1:42 p.m. The Context Camera image was taken at roughly 7:32 a.m., local solar time.
Figure 2 shows a color view cropped from a Mars Orbiter Camera daily global map acquired on the same day as the first two Mars images by the Context Camera. The map shows the planet as if every part could be imaged at some time between 1 p.m. and 3 p.m., that is, with early afternoon illumination. The cameras on Mars Reconnaissance Orbiter, conversely, imaged the planet during morning hours. The Mars Orbiter Camera view was obtained about four hours later in the day than the Context Camera data. Inserted into the daily global map are two grayscale views from the Context Camera. This shows that the Context Camera began imaging when it was over the southernmost portion of the chaotic terrain at the east end of the Valles Marineris. A second image was acquired several minutes later, as Mars Reconnaissance Orbiter flew southward towards the west side of the large Argyre impact basin. The tops of the two Context Camera images were obtained about 13 minutes apart.
Figure 3 the second image obtained by the Context Camera, is much longer than the first: 260 kilometers (162 miles) at its widest point and about 122 kilometers (76 miles) at its narrowest, some 1,590 kilometers (988 miles) to the south. It covers an area of about 40,000 square kilometers (about 15,400 square miles). The change in width reflects a change in altitude of the Mars Reconnaissance Orbiter as it descended southward toward the orbit's closest point to the planet. The picture is shown here at one-third its original scale because the file size is large.
Figure 4 contains the northernmost portion of the second Context Camera image, reproduced at one-half its original scale (because of its large file size). The white box outlines the location of the first image from the orbiter's High Resolution Imaging Science Experiment (PIA08060). The Context Camera image and the High Resolution Imaging Science Experiment image were acquired simultaneously. As with the Context Camera, the first image from the High Resolution Imaging Science Experiment was of a much lower resolution than will be obtained during the primary science phase of the Mars Reconnaissance Orbiter mission, owing to the higher altitude during this test. This figure illustrates one of the key roles that Context Camera will play during the mission -- acquiring context images for the other science instruments aboard the Mars Reconnaissance Orbiter.
Figure 1: Spirit's Long Journey, Sol 450
This perspective view of a three-dimensional terrain model shows the shape of the "Columbia Hills" landscape where NASA's Mars Exploration Rover Spirit has been working since mid-2004. North is toward the lower left. "Husband Hill" is at the center, with the "Inner Basin" behind it. This view is from images taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor and processed into a three-dimensional terrain model by the U.S. Geological Survey.
Spirit's Long Journey, Sol 450
More than 15 months after landing on Mars, NASA's Spirit rover is still going strong, having traveled a total of 4,276 meters (2.66 miles) as of martian day, or sol, 450 (April 8, 2005). This is a perspective view of the steepness of the "Columbia Hills," showing sites nicknamed "Tennessee Valley," "Larry's Lookout," "Inner Basin," "Home Plate," and the basin and summit beyond. This orbital view comprises images taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor and processed by the U.S. Geological Survey as a three-dimensional terrain model.
22 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the sinuous margin of a dust-covered, ridged lava flow in southern Daedalia Planum, Mars. The ridges on the flow formed by compression as the surface of the lava flow cooled and began to harden before the molten material of interior solidified. Note that the surface to the south (toward the bottom of the image) of the lava flow margin is more heavily cratered than the flow surface; this observation is consistent with the superposition relationship between the younger lava flow and older substrate.
Location near: 25.9°S, 128.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
7 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies overlain by seasonal frost in the north wall of an unnamed crater west of Hellas Planitia. The gullies likely formed by a combination of mass movement (i.e., landsliding) and fluid flow (i.e., water-rich debris flows). Below (south of) the gullies is a field of sand dunes; they, too, are covered by seasonal frost.
Location near: 47.4°S, 322.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
30 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows linear and barchan sand dunes in Chasma Boreale, a broad erosional trough in the martian north polar region. Winds responsible for these dunes generally blow from upper right toward the lower left. Martian dunes tend to be darker than their counterparts on Earth because they are composed of darker, iron-bearing minerals and rock fragments.
Location near: 84.2°N, 37.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
1 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margins and front of a large lava flow located on the plains southeast of Ascraeus Mons in the Tharsis region. Tharsis is the site of the majority of martian volcanoes and lava flows. In this case, lava flowed from left (west) to right (east) and flowed no further east than the margins of the flow seen in this picture.
Location near: 5.4°N, 102.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
14 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the outer edge of the south polar residual cap of Mars. During summer, the scarps that delineate the sides of the mesas, retreat (on average) by about 3 meters (~10 feet) owing to the sublimation of solid carbon dioxide.
Location near: 85.6°S, 349.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
15 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcroppings of layered, sedimentary rock in eastern Gale Crater. North-central Gale Crater is the site of a mound that is more than several kilometers thick and largely composed of sedimentary rocks that record a complex history of deposition and erosion. At one time, Gale Crater might have been completely filled and buried beneath the martian surface.
Location near: 4.9°S, 221.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
9 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a trough in the Labyrinthus Noctis region.
Location near: 1.5°S, 92.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
NASA's Mars Exploration Rover Opportunity reached the rim of "Victoria Crater" on Sept. 27, 2006, during the 951st Martian day, or sol, of the rover's work in the Meridian Planum region of Mars. Opportunity drove 9.28 kilometers (5.77 miles) in the explorations that took it from "Eagle Crater," where it landed in January 2004, eastward to "Endurance Crater," which it investigated for about half of 2004, then southward to Victoria.
This map of Opportunity's trek so far is overlaid onto images taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor. Victoria is about 800 meters (one-half mile) in diameter, or about five times wider than Endurance and 40 times wider than Eagle. The scale bar at lower right shows the length of 800 meters (0.50 mile). North is up.
The Martian sol dates in the annotated image are as follows:
sol 58 was March 24, 2004
sol 315 was December 12, 2004
sol 446 was April 26, 2005
sol 654 was November 25, 2005
sol 833 was May 28, 2006
sol 898 was August 3, 2006
sol 952 was September 28, 2006
18 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a series of small gullies on the north wall of a crater within the much larger Green Crater in Noachis Terra, Mars. The gullies might have formed by seepage and runoff of ground water; others have suggested that melting snow or ice might create such gullies. The crater floor exhibits a field of sand dunes and some wispy, dark streaks left by passing dust devils.
Location near: 53.0°S, 8.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
26 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered material exposed on a slope in the north polar region. An unconformity is visible in the middle/upper left of the image, where layers are abruptly truncated. Unconformities are indicators of drastic change in the region-the lower layers were deposited first, then eroded, then the upper layers were deposited.
Location near: 81.1°N, 75.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
11 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wide, flat-floored trough flanked by several smaller, branching troughs in the Olympica Fossae region of Mars. Dark- and intermediate-toned slope streaks -- created by dry avalanches of dust -- occur on the trough walls.
Location near: 25.1°N, 113.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
10 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows low-albedo sand dunes in the north polar region. The slip faces on the dunes face toward the lower left, indicating that the dominant winds in this region blow or blew from the upper right.
Location near: 82.4°N, 46.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
4 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the floor of a fretted terrain valley in the Coloe Fossae region. Valleys found at north middle latitudes, such as this one, often have odd linear features on them. When seen at much lower resolution by the Viking Orbiters in the late 1970s, investigators assumed that the linear features indicated flow of ice or ice-rich debris, as might occur in a glacier or rock glacier. MOC images show little evidence to support the notion that these materials flow; indeed, similar ridges occur in closed valleys, from which nothing can flow. This picture shows a close-up of one such closed valley.
Location near: 35.3°N, 303.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
Figure 1: Spirit's Long Journey, Sol 450
This view from orbit shows the region within Gusev Crater where NASA's Mars Exploration Rover Spirit has been working for the past 15 months. The view is a mosaic of images from the Mars Orbiter Camera on NASA's Mars Global Surveyor orbiter. In the left and central portion, previously released as PIA07192, tracks made by Spirit's wheels are visible from the landing site to the edge of the "Columbia Hills."
Spirit's Long Journey, Sol 450 (Full Traverse)
More than 15 months after landing on Mars, NASA's Spirit rover is still going strong, having traveled a total of 4,276 meters (2.66 miles) as of martian day, or sol, 450 (April 8, 2005). This elevation map shows the traverse followed by Spirit since arriving at the "Columbia Hills" in June, 2004. The areas colored blue are low in elevation and areas colored yellow are high in elevation. The blue area at the foot of the "Columbia Hills" is approximately 20 meters (66 feet) higher in elevation than the site where Spirit landed in Gusev Crater. The highest peak is on the order of 80 meters (262 feet) higher still. In other words, the hills Spirit is exploring are more than 250 feet high. The map imagery is from the Mars Orbiter Camera on NASA's Mars Global Surveyor.
13 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows ridges exposed by erosion in the Aeolis region of Mars. The curved and crisscrossing ridges were once channels in a fan of sediment deposited in the Aeolis lowlands. The channels were more resistant to wind erosion than the surrounding materials, so today they are left standing as ridges rather than valleys.
Location near: 6.1°S, 209.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Southern Summer
A delicate pattern, like that of a spider web, appears on top of the Mars residual polar cap, after the seasonal carbon-dioxide ice slab has disappeared. Next spring, these will likely mark the sites of vents when the carbon-dioxide ice cap returns. This Mars Global Surveyor, Mars Orbiter Camera image is about 3-kilometers wide (2-miles).
16 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of an ancient, cratered, hummocky (rough) lava flow at just the point where it encroached upon a small impact crater east of the volcano, Tharsis Tholus. The lava flow was thin enough and didn't have sufficient energy to flow into and bury the crater. Instead, it took the path of least of resistance, around the crater.
Location near: 85.5°S, 76.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
2 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows material on the floor of a crater in Noachis Terra, west of Hellas Planitia. Windblown features, both the large, dark-toned sand dunes and smaller, light-toned ripples, obscure and perhaps, protect portions of the crater floor from further modification by erosional processes.
Location near: 45.4°S, 331.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
28 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers exposed in the north polar region of Mars. The north polar cap is underlain by a thick sequence of layered material. The layers are most commonly exposed on the slopes of troughs that are believed to have formed by wind erosion. The layers give a banded appearance. In this example, some of the layers are cut off (truncated) by other layers. This truncation is a classic, textbook example of an erosional unconformity, a term commonly used by geologists. The unconformity occurs when deposition of new layered material stops for a while, and erosion occurs. Then, new layers form on top of the eroded surface and the older layers, at some point in time when the erosion stops and deposition of layered material resumes.
Location near: 78.6°N, 342.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower right
Season: Northern Spring
12 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows small wind-eroded ridges, known to geologists as yardangs, in the Eumenides Dorsum region.
Location near: 3.6°N, 150.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
12 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the floor and wall of a trough in the Acheron Fossae region of Mars. Mass movements of dry dust, which appears to mantle much of the scene, have created the dark slope streaks on the wall of the trough.
Location near: 37.5°N, 131.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
6 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the edge (running diagonally from the lower left to the upper right) of a trough, which is part of a large pit crater complex in Noachis Terra. This type of trough forms through the collapse of surface materials into the subsurface, and often begins as a series of individual pit craters. Over time, continued collapse increases the diameter of individual pits until finally, adjacent pits merge to form a trough such as the one captured in this image. The deep shadowed area is caused in part by an overhang; layered rock beneath this overhang is less resistant to erosion, and thus has retreated tens of meters backward, beneath the overhang. A person could walk up inside this "cave" formed by the overhanging layered material.
Location near: 47.0°S, 355.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
10 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a summertime view of the south polar residual cap of Mars. In this image, mesas composed largely of solid carbon dioxide are separated from one another by irregularly-shaped depressions. The variation in brightness across this scene is a function of several factors including, but not limited to, varying proportions of dust and solid carbon dioxide, undulating topography, and differences in the roughness of the slopes versus the flat surfaces.
Location near: 86.7°S, 343.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
2 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a trough cutting across a dust-covered plain in the Labeatis Fossae region of Mars. Boulders derived from the layered exposures near the top of the trough walls are resting on the floor, and in some locations, the sloping sidewalls of the dusty trough.
Location near: 22.1°N, 94.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
9 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a knob of light-toned, layered rock exposed by erosion in the Iani Chaos region of Mars. Owing to its similarity to other light-toned rock outcrops on Mars, this may be a remnant of a once more extensive sedimentary rock formation.
Location near: 1.6°S, 18.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
Figure A
Annotated Image
Figure B
Annotated Image
No Annotation
Figure C
Annotated Image
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While most of the new impact craters found on Mars by the Mars Global Surveyor's Mars Orbiter Camera have dark ejecta patterns, a few of them also have light-toned ejecta, indicating that the impacting meteorite excavated to a depth where a light-toned material was present.
Figure A: The picture was acquired on Feb. 26, 2006. The single small crater of about 22.6 meters (about 74 feet) in diameter is surrounded by light and dark-toned ejecta. The crater occurs near 20.6 degrees north latitude, 356.8 degrees west longitude, in Arabia Terra.
Figure B: This set of images shows how the impact site appeared to the Mars Odyssey Thermal Emission Imaging System infrared instrument before and after the impact. The white circle indicates the location of the impact site. Both images are from the Thermal Emission Imaging System band 9 (approximately 12.6 micrometers wavelength); the first image was obtained on June 30, 2002, the second on Oct. 5, 2003. In the 2003 image, the impact site appears as a bright spot, because it was warmer than the surroundings at the time the data were acquired.
Figure C: The final figure shows how the impact site appeared to the Mars Global Surveyor Mars Orbiter wide-angle cameras. The first image shows the site before the impact, on Aug. 31, 1999. The second shows the impact site as it appeared on May 7, 2003.
Taken together, the Mars Odyssey and Mars Global Surveyor data indicate that this impact occurred some time between June 30, 2002, and May 7, 2003.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
5 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cratered plain west of Schiaparelli Crater, Mars. The area captured in this image, and areas adjacent to it, are known for high dust devil traffic and the day this image was acquired in March 2006 was no exception. Near the top of the image, diagonally from the large impact crater cut by the left (west) edge of the image, there is a large dust devil traversing the plain and casting a shadow to the east. Also, near the bottom of the image, a smaller dust devil, is working its way across the plain.
Location near: 5.9°S, 349.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
Figure A
Annotated Image
No AnnotationFigure B
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Figure C
Annotated Image
No Annotation
Of the 20 new impact craters found on Mars by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) in 2006, the one shown here is perhaps the prettiest. The darkened "blast zone" around the crater exhibits considerable details about how the energy transferred from the impact to the surrounding atmosphere and dust-mantled surface interacted. Wispy dark rays and dark, annular (nearly-circular) zones surround the crater, while several chains of dark spots formed by secondary impact radiate away for hundreds of meters from the tiny crater.
This impact site has a single crater of about 22.6 ± 1.7 meters (about 75 feet) in diameter. Compare this with the typical 100 yard U.S.-style football field: 75 feet is about 24.7 yards. The crater is located in Arabia Terra near 26.4°N, 336.5°W.
This picture is a colorized view of the crater. The image is a sub-frame of MOC narrow angle camera image S16-01674, obtained on 20 March 2006. The color comes from a look-up table derived from the colors of Mars as seen by the Mars Reconnaissance Orbiter's High Resolution Stereo Camera (HRSC).
Figures A and B: These pictures are grayscale composites of portions of MOC images S16-01674, S17-00795, S17-02191, and S18-01407, showing the impact site and the extensive rays developed during the impact event. These data were acquired during March, April, and May 2006.
Figure C: This picture shows how the age of the crater was constrained. The first (left) is a portion of MOC red wide angle camera image R12-00786, acquired on 8 December 2003. The white circle indicates the location of the impact site, but the impact had not yet occurred. The second picture (right) shows the same MOC red wide angle image, overlain by a portion of an image from the Mars Odyssey Thermal Emission Imaging System (THEMIS). The THEMIS image is an infrared picture (I17523014, band 9, ~12.6 micrometers) acquired on 26 November 2005. In the infrared image, the impact site shows up as a bright spot because it is warmer than its surroundings during the day. These two pictures, thus, tell us that the impact occurred some time between 8 December 2003 and 26 November 2005.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
6 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a chain of clustered and battered craters. These were formed by secondary impact. That is, somewhere to the south (beyond the bottom of this image), a large impact crater formed. When this occurred, material ejected from the crater was thrown tens to hundreds of kilometers away. This material then impacted the martian surface, forming clusters and chains of smaller craters.
Location near: 15.8°N, 35.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
10 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark sand dunes, formed by winds blowing from the southwest (lower left), in Wirtz Crater. The crater is named for Carl Wilhelm Wirtz (1876-1939), a German astronomer.
Location near 49.0°S, 25.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
18 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows broken-up blocks of sedimentary rock in western Candor Chasma. There are several locations in western Candor that exhibit this pattern of broken rock. The manner in which these landforms were created is unknown; it is possible that there was a landslide or a meteoritic impact that broke up the materials. One attribute that is known: in some of these cases, it seems that the rock was broken and then buried by later sedimentary rocks, before later being exhumed so that they can be seen from orbit today.
Location near: 6.9°S, 75.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
12 April 2006
Today, the MOC Team celebrates the 45th anniversary of the first human flight into space, that of Yuri Gagarin on 12 April 1961, and the 25th anniversary of the first NASA Space Shuttle flight on 12 April 1981, by briefly pondering the wonders of our Solar System and the opportunities of the age in which we live. Although humans have not ventured to the Moon in more than 30 years, and have not yet gone to Mars, we can all go there through the eyes of our robotic explorers.
Mars, perhaps the most Earth-like (yet so very different!) planet in our star's system, is tilted on its axis by about 25°-not all that different than Earth's ~23.5°. Thus, Mars, like Earth, experiences a changing of seasons as the planet revolves around the Sun. At high latitudes in each hemisphere during autumn and winter, carbon dioxide frost accumulates on the surface.
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes covered and delineated by seasonal frost in the north polar region of Mars. The winds responsible for the formation of these dunes blew primarily from the northwest (upper left), with additional influences from the north and northeast. During the late spring and summer seasons, these dunes would look much darker than their surroundings, but in this late winter image, the dunes and the plains on which they occur are all covered with carbon dioxide frost.
Location near: 78.4°N, 76.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
21 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a mesa in eastern Candor Chasma. The mesa appears to be composed of at least two different rock types based on the near-vertical appearance of the scarps which define the top portion of the mesa and the gentler slopes that extend down to where the base of the mesa meets the chasm floor. The uppermost rock unit is more resistant to erosion, and thus is harder.
Location near: 7.6°S, 65.5°W
Image width: ~2 km (~1.2 mi)
Illumination from: upper left
Season: Southern Summer
Figure 1: Spirit's Long Journey, Sol 450
This view from orbit shows the region in the "Columbia Hills" where NASA's Mars Exploration Rover Spirit has been working since mid-2004. The area in the image is about 2.3 kilometers (1.4 miles) across. North is to the top. The bright region near the center is the north flank of "Husband Hill." The imagery is from the Mars Orbiter Camera on NASA's Mars Global Surveyor.
Spirit's Long Journey, Sol 450 (Detail)
More than 15 months after landing on Mars, NASA's Spirit rover is still going strong, having traveled a total of 4,276 meters (2.66 miles) as of martian day, or sol, 450 (April 8, 2005). This orbital view shows the path of Spirit's trek through the "Columbia Hills," beginning on the "West Spur" on sol 156 (June 11, 2004) and continuing up the flanks of "Husband Hill." The dashed line indicates the perimeter of the Columbia Hills, which consist of older rocks of different composition than those of the surrounding plain. The path of Spirit's trek is overlain on imagery from the Mars Orbiter Camera on NASA's Mars Global Surveyor. The 500-meter scale bar is 1,640 feet long.
27 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted, eroded remains of a channel -- now standing as a complex ridge that runs across the middle of this scene -- in dust-mantled terrain west of Sinus Meridiani, Mars. The original channel might have been carved by running water, but too little detail remains today to provide any certainty as to whether water was the culprit.
Location near: 5.6°N, 7.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
8 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered, light-toned exposures of probable sedimentary rock in Iani Chaos. Near the right (east) edge of the scene are relatively small, remnant buttes and mesas composed of the light-toned rock which makes up the large plateau on the west edge of the image.
Location near: 1.6°S, 18.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
24 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a relatively fresh crater with dark, rayed ejecta on an upland plain above one of the many depressions in the eastern Labyrinthus Noctis region. The presence of the dark rays emanating from the crater suggests that the impact was a relatively recent event compared to other craters of similar diameter in the scene. Over time, the dark ejecta will fade and blend in with its surroundings, owing to settling of dust from the atmosphere.
Location near: 9.7°S, 94.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
16 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater that is approximately 3.5 kilometers (2.2 miles) in diameter. It is located to the northeast of Olympus Mons, in the Tharsis Region. Layered rock units are visible on the inside of the raised crater rim.
Location near: 70.7°N, 271.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
30 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example of the extremely odd, seemingly scrambled layered rocks exposed by erosion near the deepest part of the deepest basin on Mars, Hellas. This pattern of eroded, and perhaps deformed layers was once exposed to the martian surface, then buried, and more recently exposed again. The story behind these layers is not really understood; some members of the MOC team have -- for nearly 9 years now -- taken to calling these features, "taffy-pull terrain."
Location near: 43.1°S, 307.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Spring
25 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers and dunes in Chasma Boreale, a large depression in the north polar region.
Location near: 85.2°N, 10.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
31 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows streaks and scratch marks made in a thin coating of dust on the martian surface in the southern hemisphere. These streaks were made by passing dust devils during the summer season.
Location near: 62.6°S, 89.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
21 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a plain covered by flow material that surrounded and banked against three older, rounded hills in the Zephyria region. Although some investigators have proposed that the flows covering plains in this region are the remains of an ice-covered lake, others have found considerable evidence, including small volcanoes, to suggest that the flows are volcanic. The textures on these flows resemble that of some of the lava flows in the volcanic Tharsis region of Mars.
Location near: 2.7°S, 195.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
28 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a trough partly filled by large, windblown ripples in the Tempe Terra region of Mars.
Location near: 36.5°N, 65.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
31 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.2 km north mid-latitude crater with a bright wind streak.
Location near: 30.8°N, 131.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
8 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a large dust devil flanked by two relatively small dust devils, moving together across a lightly-dusted, south high-latitude plain.
Location near: 65.6°S, 20.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
10 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the intersection of channels formed by collapse on the northeastern flank of Ascraeus Mons.
Location near: 14.2°N, 100.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
31 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a "pancake" or "pedestal" crater on the martian northern plains. The rocky ejecta from the crater protected the underlying material from being stripped away by wind, leaving the ejecta standing higher than the surrounding terrain. The rocks in the ejecta are not too clearly seen today, especially at the 6 meters (~20 feet) per pixel scale of this image, in part because they have been covered up by later, mantling material.
Location near: 60.0°N, 265.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
19 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark north polar dunes overlying other materials in the north polar region.
Location near: 79.1°N, 228.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
4 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows ancient, dust-covered lava flows and remains of leveed lava channels located on a plain northwest of Jovis Tholus. Jovis is a relatively small volcano in the Tharsis region of Mars.
Location near: 22.4°N, 122.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
4 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered, light-toned outcrops of sedimentary rock in Becquerel Crater. The outcrops are juxtaposed against a dark-toned substrate which occupies the upper (northern) portion of the image. Dark dunes and patches of windblown sand superpose both the light-toned rock and darker substrate; dark sand trapped among the layers of sedimentary rock enhances their appearance.
Location near: 21.5°N, 8.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
15 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a landslide that occurred off of a steep slope in Tithonium Chasma, part of the vast Valles Marineris trough system.
Location near: 4.8°S, 84.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
4 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a valley in Xanthe Terra.
Location near: 5.2°N, 46.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
2 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a pedestal crater in the Promethei Terra region. The ejecta from an impact crater is usually rocky. The rocks in the ejecta help shield the terrain beneath the ejecta from being eroded away by wind. Thus, over time, some craters appear to be raised on pedestals defined by their ejecta blankets, because wind has stripped away tons and tons of surrounding material.
Location near: 65.4°S, 264.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
15 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted traces of old channels in a complex, wind-eroded fan located in the Aeolis region of Mars.
Location near: 6.3°S, 208.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
16 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown materials that have collected and been shaped into large ripples in a valley in the Auqakuh Vallis system in northeastern Arabia Terra, Mars.
Location near: 29.1°N, 299.6°W
Image width: ~2 km (~1.2 mi)
Illumination from: lower left
Season: Northern Winter
3 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes covered with a seasonally-deposited layer of solid carbon dioxide (CO2) in the north polar region of Mars. The dark spots indicate areas where the CO2 frost has begun to change, either by being sublimed away, or by becoming rougher or coarser-grained, such that it appears darker than surrounding frost. Over the course of the spring season, the frost will be completely removed and the dark sands that make up the dune field will be visible by summer.
Location near: 77.7°N, 41.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
6 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows south polar mesas composed largely of solid carbon dioxide separated by generally circular depressions. The arcuate scarps, which delineate the mesas, retreat approximately 3 meters per Mars year (two Earth years), owing to sublimation which occurs primarily during the martian summer months.
Location near: 86.9°S, 340.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
5 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the outer edge of the south polar residual cap of Mars during southern summer. The variability in brightness across the image would not be as apparent had the data been acquired during late winter or spring, owing to the presence of seasonally deposited, carbon dioxide frost. Over the spring and into early summer, the seasonal carbon dioxide is removed through sublimation, and then the thicker, older accumulations of carbon dioxide -- deposited hundreds or thousands of years ago -- erodes. As this occurs, some surfaces become darker, either because they are roughened by erosion, contain dark material such as mineral dust, or both.
Location near: 86.9°S, 111.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
3 September 2006
Viking 2 landed 30 years ago today, on 3 September 1976. It was the second of the two Viking landings on Mars. Viking 1 touched down on 20 July 1976. Since the Viking missions of the 1970s, only 3 additional spacecraft have successfully landed and conducted their scientific investigations: Mars Pathfinder (1997), Mars Exploration Rover Spirit (2004-present), and Mars Exploration Rover Opportunity (2004-present). Two new U.S. Mars landed missions are currently in the works: Phoenix, launching in August 2007, and MSL (Mars Science Laboratory), launching in 2009.
As with the 30th anniversary of the Viking 1 landing in July (see PIA08616),for the Viking 2 30th anniversary, we show here the best Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) view of the landing site.
On that day 30 years ago, Viking 2 landed in Utopia Planitia, west of Mie Crater, near 48.0°N, 225.7°W. At the time, it was considered that this might be a good place to look for evidence of life in the martian regolith. This middle north latitude site is often obscured by clouds in the winter and dust hazes in the spring. The surface was observed by the lander to be dusted by thin coatings of frost during the winter months.
The exact location of the Viking 2 lander was uncertain until MOC obtained the high resolution view, shown above, in 2004. These images were previously released by the MOC team on 5 May 2005, along with what was then considered to be the best candidate for the Mars Polar Lander site (see "MGS Finds Viking 2 Lander and Mars Polar Lander (Maybe)"). The candidate Polar Lander site was further imaged in 2005 and found not to be the lander (see PIA03044).
Figure 1 shows (A) a mosaic of Viking Orbiter images obtained in the 1970s at a resolution of 75 m/pixel, (B) a typical MGS MOC narrow angle camera view at about 3 meters/pixel (25x higher resolution than the Viking images), and (C, D) sections of a MOC image obtained at ~0.5 m/pixel. Figure 2 shows an extreme enlargement of the feature identified as Viking Lander 2, compared to a schematic drawing of the lander in the orientation determined during the Viking mission.
31 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a layered, light-toned mesa among other layered materials exposed in a mound that covers much of the floor of Spallanzani Crater.
Location near: 58.3°S, 273.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
13 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies on northern wall of a south mid-latitude crater.
Location near: 35.8°S, 220.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Spring
19 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the contact between an area of light-toned rock and an expanse of darker-toned materials on the floor of Coprates Chasma. Remnants -- bits and pieces -- of the light-toned material are scattered throughout the scene, indicating that this material once covered everything in this area. Coprates is one of several chasms that comprise the giant Valles Marineris trough system.
Location near: 13.2°S, 61.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
26 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a spine of material exposed in the Sisyphi Planum region of Mars. Gullies can be seen on the deeply-shadowed ridge slope. Mass movement (landsliding) has contributed to the erosion of this ridge and the creation of the apron of talus that surrounds it.
Location near: 70.7°S, 357.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
16 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some dark slope streaks in the Phlegra Dorsa region of Mars. Of particular interest is the split streak near the center of the image, which diverted around a rounded hill as the material was sliding down the slope. Slope streaks occur in regions of Mars that are mantled by fine, bright dust. They do not occur on slopes that have no dust coating. They are therefore suspected to form by dry avalanching of the dust, despite their somewhat fluid appearance.
Location near: 24.9°N, 184.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Spring
This imagery from the panoramic camera on NASA's Mars Exploration Rover Opportunity shows the outcrop-rimmed "Beagle Crater" appearing on the horizon as Opportunity approaches it. The top version is vertically stretched to make horizon details easier to see. The lower version has normal proportions. The image is a mosaic of frames taken during Opportunity's 855th Martian day, or sol (June 20, 2006).
Beagle Crater is 35 meters (115 feet) in diameter. The Opportunity science and engineering teams hope to have the rover visit it on the way to "Victoria Crater." Beagle Crater was 310 meters (1,107 feet) away from Opportunity when this picture was taken. Even at this distance, blocks of ejecta can be seen around the prominent, raised rim of Beagle crater, suggesting that it may be among the youngest craters visited by Opportunity.
When scientists using orbital data calculated that they should be able to detect Victoria's rim in rover images, they scrutinized frames taken in the direction of the crater by the panoramic camera. To positively characterize the subtle horizon profile of the crater and some of the features leading up to it, researchers created this vertically-stretched image (top). The stretched image makes mild nearby dunes look like more threatening peaks, but that is only a result of the exaggerated vertical dimension. This vertical stretch technique was first applied to Viking Lander 2 panoramas by Philip Stooke, of the University of Western Ontario, Canada, to help locate the lander with respect to orbiter images. Vertically stretching the image allows features to be more readily identified by the Mars Exploration Rover science team. The bright white dot on the horizon near the upper left corner of the panorama, labeled "Outcrop Promontory," was thought to be a light-toned outcrop on the far wall of Victoria, based on a single azimuth measurement on sol 804 (April 28, 2006), suggesting that the rover was seeing over the low rim of Victoria. But comparing the azimuth angle of this feature in the sol 855 panorama and the angle of the same feature in the sol 804 panoramic image, PIA08447 (a process known as triangulation) revealed that this outcrop must instead be on the near rim of the crater.
The southeast rim of Victoria is labeled in bright green. The northeast rim is beyond the left edge of this panorama. The salmon-color lines and arrows highlight two small craters on the dark "annulus," or ring, around Victoria Crater.
29 March 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the northern wall complex of a crater in northwest Terra Sirenum. Several spectacular gully networks extend from a variety of elevations on the wall and run downslope toward the crater floor (bottom of image). The genesis of these features is still hotly debated in the Mars science community. Among the possibilities is that of a combination of mass movement and groundwater seepage and runoff.
Location near: 39.2°S, 164.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
26 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a variety of textures observed on a dust-covered plain in the Marte Valles region of Mars. Textural variations across the scene include: areas that are littered with small impact craters, a channel-like feature that is dominated by mounds of a variety of sizes, small ripples and/or ridges, and relatively smooth, unremarkable terrain. The contact between the cratered plain and the area dominated by mounds marks one of the banks along the edge of one of the shallow valleys of the Marte Valles system.
Location near: 17.7°N, 175.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
This global map of Mars is based on topographical information collected by the Mars Orbiter Laser Altimeter instrument on NASA's Mars Global Surveyor orbiter. Illumination is from the upper right. The image width is approximately 18,000 kilometers (11,185 miles). Candor Chasma forms part of the large Martian canyon system named Valles Marineris. The location of Southwest Candor Chasma is indicated in the annotated version.
Voir l'image PIA10132: Global View of Mars Topography sur le site de la NASA.
Figure A
Annotated Image
No AnnotationFigure B
Annotated Image
No Annotation
Two of the 20 new impact craters determined by the Mars Global Surveyor's Mars Orbiter Camera science operations team to have formed between May 1999 and March 2006 occur at a location that the narrow-angle camera imaged previously. This is surprising given that the narrow-angle camera, with its 3-kilometer-wide (1.9-mile-wide) field of view, has only covered about 5.2 percent of the Martian surface. One of the two craters that formed where the camera had already taken a narrow-angle image is featured here.
Figure A: The colorized image and figure A show sub-frames of an image acquired on March 13, 2006. This image has been colorized using a table derived from the colors of Mars as seen by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera. The impact site is located near 27.3 degrees north latitude, 91.8 degrees west longitude, on the upper north flank of the Martian volcano Ulysses Patera. Fine details are evident at the impact site, showing how the blast moved dust around and interacted with craters and other small obstacles on the ground. The crater has a diameter of about 19.8 meters (about 65 feet).
Figure B: The second figure shows before-and-after narrow-angle camera views of the impact site. The before image was acquired on Feb. 24, 2002. The after image was acquired on March 13, 2006.
Other images from Mars-orbiting spacecraft cover this location and show the impact site, including data from the Mars Express High Resolution Stereo Camera and Mars Odyssey Thermal Emission Imaging System. These other data help constrain when the impact occurred. The last orbiter image obtained before the impact was taken on April 18, 2003. The first orbiter image that showed the impact feature was obtained on Feb. 7, 2004. Thus, the impact occurred between those dates, April 18, 2003, and Feb. 7, 2004.
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, also in Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
7 August 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a flow or landslide feature on a hillslope facing north (toward top/upper right) that is buried on both ends. Both the uphill portion of the slide (just below the center of the image) and the bottom end of the slide, or flow feature (near the upper right corner of the image), is buried. Whether this partially buried landform was formed by simple, dry mass movement (a landslide) or by flow of an ice-rich material, is unclear. The features in this image occur among the massifs located east of the Hellas basin.
Location near: 45.6°S, 248.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
11 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark lava flows that have embayed -- flowed up against and into -- higher, more rugged terrain in the Cyclopia/Aethiopis region of Mars (southwest of Cerberus). Because they are relatively dark, these flows might have very little dust mantling them; these might be among the youngest lava flows on the planet. Nevertheless, the flow material does have a few small impact craters that formed in its surface, indicating that it is not extremely young.
Location near 6.0°N, 220.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Autumn
3 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a cratered plain in the Athabasca Vallis region of Mars. Remarkably, the cratered plain in this scene is essentially free of bright, windblown ripples. Conversely, the lava flow apparently acted as a trap for windblown materials, illustrated by the presence of the light-toned, wave-like texture over much of the flow. That the lava flow surface trapped windblown sand and granules better than the cratered plain indicates that the flow surface has a rougher texture at a scale too small to resolve in this image.
Location near: 10.7°N, 204.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
25 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the patterned ground of the cold, martian northern plains. The circular features are the sites of buried impact craters.
Location near: 70.5°N, 340.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower right
Season: Northern Spring
25 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies in the north wall of a crater south of Proctor Crater in Noachis Terra. To form, the gullies might have required liquid water. Dark streaks cutting across the scene were formed by passing dust devils.
Location near: 51.4°S, 331.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
11 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows adjacent impact craters located north-northwest of the Acheron Fossae region of Mars. The two craters are of similar size and formed by meteor impacts. However, one is much more filled than the other, indicating that it is older. The surface of the material in the older, partially-filled crater has a texture similar to the crater's surroundings. The southern (bottom) crater is bowl-shaped and is also partially-filled, however, the filling material seems to be limited to the southern half of the crater.
Location near: 44.6°N, 128.4°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
3 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers exposed by erosion in a trough within the north polar residual cap of Mars, diving beneath a younger covering of polar materials. The layers have, since the Mariner 9 mission in 1972, been interpreted to be composed of a combination of dust and ice in unknown proportions. In this scene, a layer of solid carbon dioxide, which was deposited during the previous autumn and winter, blankets the trough as well as the adjacent terrain. Throughout northern spring, the carbon dioxide will be removed; by summer, the layers will be frost-free.
Location near: 81.4°N, 352.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
Figure A
Annotated Image
Figure B
Annotated Image
No AnnotationFigure C
Annotated Image
No Annotation
Pictured here is the second of 2 of the 20 new impact craters identified by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) science operations team to have formed between May 1999 and March 2006 that occur at a location that the MOC narrow angle camera imaged previously. This is surprising, given that the narrow angle camera, with its 3 kilometer- (1.9 miles)-wide field of view, has only covered about 5.2% of the martian surface. The other such case is described in an accompanying release, "One of Two Fresh Impact Crater Sites With Before and After Narrow Angle Mars Orbiter Camera Images" (see PIA09023 or MOC2-1614).
Figure A: This picture shows the impact site. It is located in Arabia Terra near 25.8°N, 308.0°W. The figure is a composite of sub-frames of MOC images S15-02322, obtained on 22 February 2006, and S17-01393, from 17 April 2006. The largest crater at the center of the impact zone has a diameter of about 16.0 ± 1.7 meters (about 52 feet). Several other smaller craters were formed by this impact event.
Figure B: This figure shows how the impact site appeared in a previous MOC narrow angle camera image, R13-00039, on 1 January 2004, before the impact occurred. This is compared with MOC image S15-02322, obtained after the impact.
Figure C: This figure shows the impact site as it appeared to the Mars Odyssey Thermal Emission Imaging System (THEMIS) visible camera on 21 December 2005. Most importantly, the crater did not exist on 21 December 2005, but the dark spot the impact produced was seen 42 days later in MOC red wide angle image S14-03311 on 31 January 2006. In other words, the impact occurred between 21 December 2005 and 31 January 2006. It is possible that the crater formed in January 2006, after we began our survey for fresh martian impact craters!
The Mars Global Surveyor mission is managed for NASA's Office of Space Science, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft. Malin Space Science Systems, San Diego, Calif., built and operates the Mars Orbiter Camera.
For more information about images from the Mars Orbiter Camera, see http://www.msss.com/mgs/moc/index.html.
This perspective view looking toward the northeast shows part of the Columbia Hills range inside Gusev Crater. At the center is the winter campaign site of NASA's Mars Exploration Rover Spirit.
On its 805th Martian day, or sol, (April 8, 2006), Spirit was parked on a slope tilting 11 degrees to the north to maximize sunlight on the solar panels during the southern winter season. Science observations were formulated to take advantage of the long time during which the rover was parked. The plan focused on two tasks: tracking atmospheric and surface dynamics by periodically surveying the surface and atmosphere; and extensively examining surrounding terrains, rocks and soils using the panoramic camera and the miniature thermal emission spectrometer, coupled with long duration measurements using the alpha particle X-ray and Moessbauer spectrometers of rock and soil targets. For reference, the feature known as "Home Plate" is approximately 90 meters (295 feet) wide.
An image from Mars Global Surveyor's Mars Orbital Camera, catalogued as E03_00012 and courtesy Malin Space Science Systems, was used as the base image for this figure. The perspective was generated using elevation data generated from analyses of the camera's stereo images by the U.S. Geological Survey, Flagstaff, Ariz.
13 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows exhumation of flow surfaces from beneath a material that was eroded by wind in the Cerberus/Zephyria region. The origin of the flow material has been a subject of debate among Mars scientists; it may have been very fluid lava or mud flows. In either case the material was buried for some time.
Location near: 34.2°N, 207.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Northern Summer
20 July 2006
Viking 1 landed 30 years ago today, on 20 July 1976. It was the first U.S. landing on Mars and a very exciting time for Mars exploration. Since that time, four additional spacecraft have successfully landed on Mars and conducted their science investigations. Today, new missions to the martian surface are in the works, with landings expected in 2008 (Phoenix) and 2010 (Mars Science Laboratory).
The Viking 1 lander is difficult to see in Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images. The western Chryse Planitia landing site is often obscured by dust hazes and occasional storms, especially during northern winter, which would otherwise be the best time to look for the lander from orbit because the sun casts longer shadows in winter. When the atmosphere is clearest, in portions of the spring and summer, the sun is higher in the sky as seen from MGS's orbit. The spacecraft always passes over the landing site region around 2 p.m. in the afternoon. The suite of pictures shown here describes the best MOC view of the landing site. These were previously released in May 2005, but the MOC team felt that 20 July 2006 is an appropriate time to review this story.
The first figure (left) visually tells how the lander was found. The initial observations of the location of Viking 1, as originally determined by members of the Viking science team based on sightlines to various crater rims seen in the lander images (black lines), did not show the detailed features we knew from the lander pictures (middle) to be in the area. Using geodetic measurements, the late Merton Davies of the RAND Corporation, a MGS MOC Co-Investigator, suggested that we should image areas to the east and north of where Viking 1 was thought to be. Timothy J. Parker of the Jet Propulsion Laboratory (Pasadena, California), using sightlines to crater rims seen in the lander images (white lines), deduced a location very close to that suggested by Davies. The MOC image of that location, acquired in 2003, showed additional near-field features (rocks associated with a nearby crater) that closely matched the Viking 1 images (center and right frame, where B denotes "Volkswagen Rock"). The inset (upper right) is an enlargement that shows the location of the Viking 1 lander.
The MOC image of the Viking 1 lander site (right) was acquired during a test of the MGS Pitch and Roll Observation (PROTO) technique conducted on 11 May 2003. (Following initial tests, the "c" part of "cPROTO" was begun by adding compensation for the motion of the planet to the technique). The PROTO or cPROTO approach allows MOC to obtain images with better than its nominal 1.5 meters (5 ft) per pixel resolution. The image shown here (right) was map projected at 50 centimeters (~20 inches) per pixel. The full 11 May 2003 image can be viewed in the MOC Gallery, it is image R05-00966.
In addition to celebrating the 30th anniversary of the first U.S. robotic Mars landing, we note that 20 July is also the 37th anniversary of the first human landing on the Moon, on 20 July 1969. There are two dates that are most sacred in the space business (three, if you count the 4 October 1957 launch of Sputnik 1). The other date is 12 April, which celebrates the 1961 launch of the first human in space, and the 1981 launch of the first space shuttle orbiter.
13 May 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small portion of Evros Vallis, an ancient valley located south of the large impact basin, Schiaparelli. In this image, the walls and floor of the valley, as well as the adjacent upland, are all mantled by dust. In addition to the dust mantle, large, windblown ripples occur in low-lying areas, particularly on the valley floor. The ripples, also, have been covered by dust.
Location near: 12.7°S, 346.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
20 May 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies formed on an equator-facing slope among mounds in Acidalia Planitia. Similar gullies occur in a variety of settings at middle and polar latitudes in both martian hemispheres.
Location near: 49.8°N, 22.7°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
5 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the margin of a lava flow on a plain northwest of Jovis Tholus, a volcanic construct located in the Tharsis region of Mars. To the north (top) of the lava flow, islands of a material that was once more laterally extensive are present, suggesting that at some time in the past, a great deal of this material was removed by erosion -- perhaps a catastrophic flood of water and debris. The lava flow at the south (bottom) came in later, long after the erosional events occurred.
Location near: 20.9°N, 118.9°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Winter
14 March 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows north polar dune morphologies.
Location near: 78.0°N, 256.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
Click on the image for movie of
Animated Elevation Model of 'Victoria Crater'
After driving more than 9 kilometers (5.6 miles) from the site where it landed in January 2004, NASA's Mars Exploration Rover Opportunity approached "Victoria Crater" in September 2006. The crater is about 750 meters (half a mile) across. That is about six times wider than "Endurance Crater," which Opportunity spent six months examining in 2004, and about 35 times wider than "Eagle Crater," where Opportunity first landed. The walls of Victoria hold the scientific allure of much taller stacks of geological layers -- providing the record of a longer span of the area's environmental history -- than Opportunity has been able to inspect on the Meridiani plains or at smaller craters.
This animation created by the U.S. Geological Survey uses a digital elevation model generated from computer analysis of three images taken by the Mars Orbiter Camera aboard NASA's Mars Global Surveyor orbiter. The vertical dimension is not exaggerated relative to the horizontal dimensions. The crater is about 70 meters (230 feet) deep.The images used for providing the stereo information to calculate relative elevation were taken on Feb. 1, 2004 (http://www.msss.com/moc_gallery/r10_r15/images/R14/R1401689.html) and April 16, 2005 (http://www.msss.com/moc_gallery/s05_s10/images/S05/S0500863.html). The animation begins and ends with the view looking from the northwest toward the southeast. Opportunity is approaching Victoria from the northwest.27 September 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-toned, windblown sands and ripples, surrounding a light-toned hill, interpreted to be sedimentary rock, in Ganges Chasma. Ganges Chasma is part of the giant Valles Marineris trough system on Mars.
Location near: 8.6°S, 46.1°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper right
Season: Southern Autumn
Dark spots (left) and 'fans' appear to scribble dusty hieroglyphics on top of the Martian south polar cap in two high-resolution Mars Global Surveyor, Mars Orbiter Camera images taken in southern spring. Each image is about 3-kilometers wide (2-miles).
15 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a mid-summer view of a portion of the south polar residual cap of Mars. The large, relatively flat-lying, puzzle-like pieces in this scene are mesas composed largely of solid carbon dioxide.
Location near: 85.5°S, 76.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
22 July 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes in the north polar region of Mars. In this scene, the dunes, and the plain on which the dunes reside, are at least in part covered by a bright carbon dioxide frost. Dark spots indicate areas where the frost has begun to change, either by subliming away to expose dark sand, changing to a coarser particle size, or both. The winds responsible for the formation of these dunes blew from the lower left (southwest) toward the upper right (northeast).
Location near: 76.3°N, 261.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
9 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows patterned ground on the martian northern plains. The circular features are buried meteor impact craters; the small dark dots associated with them are boulders. The dark feature at left center is a wind streak.
Location near: 75.1°N, 303.0°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
10 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a light-toned wind streak created in the lee -- the downwind side -- of an impact crater in the Cyane Fossae region of Mars. Winds blowing from the bottom (south) toward the top (north) swept this scene clean of fine, bright dust except for the dust that had accumulated in a few protected areas such as that in the lee of this crater.
Location near: 42.0°N, 125.8°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
19 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a pair of partially-buried impact craters which are being exhumed on a plain east of Hellas in the Promethei Terra region Mars.
Location near: 45.5°S, 256.5°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Autumn
17 June 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a group of sand dunes, covered by seasonal carbon dioxide frost, in the martian north polar region. Over the course of northern hemisphere spring, the carbon dioxide frost sublimes away, slowly revealing the dark sand that makes up the dunes. The dark spots in this image may be patches of freshly-exposed sand, or they could be places where the CO2 frost has changed, either becoming rougher, coarser-grained (larger crystals), or both. A rougher or coarser-grained surface will appear darker because of an increase in shadowing of the surface by the small-scale roughness elements.
Location near: 75.2°N, 51.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: lower left
Season: Northern Spring
Thomas A. Mutch has been called an explorer of two worlds. Known to colleagues as Tim, he was born on August 26, 1931. An avid mountaineer as well as a scientist, he climbed in the Canadian Rockies and the Himalayas, and had a passion for exploration in all its forms. Mutch became a geologist after majoring in history at Princeton; he received a master's degree from Rutgers and a doctorate from Princeton. In 1960 he became a geology professor at Brown University, later serving as department chairman.
In the late 1960s, Mutch applied the geologic discipline called stratigraphy to the study of features on the Moon, work that led to his writing the landmark book, The Geology of the Moon. Mutch went on to become the leader of the Viking Lander Imaging Team, which had responsibility for obtaining and interpreting the first images from the surface of Mars. Following the successful touchdowns of Viking 1 on July 20, 1976 and Viking 2 a few weeks later, the twin landers transmitted a total of more than 4,000 images from the Martian surface.
Mutch had an ability to inspire those around him and a dedication to involving young people in the experience of exploration. He helped create the Viking Student Intern program, a pioneering educational activity since duplicated by many planetary missions, which allowed several dozen college students to participate in the Viking mission. At Brown, where he taught a seminar in exploration, he invited students to participate in a Himalayan climbing expedition. In May 1978, Mutch led a team of 32 students, faculty, and alumni to the21,900-foot Indian peak Devistan; 24 of them, including Mutch, made it to the summit.
In October 1980, Mutch died on the slopes of Mount Nun in the Himalayas, following a climbing accident while descending from the 23,410-foot summit. At the time he was on leave from Brown, serving as NASA's Associate Administrator for Space Science. His legacy endures in the many minds and spirits he helped nurture. In the planetary science community his former students include R. Stephen Saunders, James W. Head, III, Raymond E. Arvidson, and James B. Garvin. In 1981, NASA administrator Robert Frosch announced that the Viking 1 lander had been renamed the Mutch Memorial Station, and unveiled a stainless steel plaque that is to be placed on the lander, someday, by a team of explorers. The inscription on the plaque reads, "Dedicated to the memory of Tim Mutch, whose imagination, verve, and resolve contributed greatly to the exploration of the Solar System."
Located at 0.6°N, 55.3°W, Mutch Crater is about 211 kilometers (131 miles) in diameter. Naming of this crater for Tim Mutch was approved by the International Astronomical Union (IAU) in 1985.
The main image is a mosaic of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red wide angle images acquired during the MOC Geodesy Campaign in May 1999. The white boxes show the location of figures 1 and 2. Figure 1 is a mosaic of MOC and lower-resolution Mars Odyssey THEMIS VIS images that cover a smaller, unnamed crater located in west-central Mutch Crater. Figure 2 is a portion of the mosaic of the small, unnamed crater, showing landslide deposits formed when material slumped off the crater wall. The source alcoves of the landslides are well defined, as are longitudinal troughs and ridges on the surface of the landslides. These mass movements occurred long after the crater was formed, judging by the difference in the number of small impact craters on their surfaces and on the nearby floor of the crater.
The view of the landslides in the northeast corner of the small, unnamed crater in Mutch was acquired by the MGS MOC just a few days ago, on 23 August 2006, to commemorate the 75th birthday of Tim Mutch on 26 August 2006.
Noted space writer Andrew Chaikin (http://www.andrewchaikin.com), a former Tim Mutch student, suggested the 23 August 2006 MGS MOC image and contributed to the text of this release.
30 April 2005
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows wind-eroded sedimentary rocks in Tithonium Chasma, one of the troughs of the Valles Marineris system. The winds responsible for the majority of the erosion blew from the northeast (upper right), creating yardangs (wind erosion ridges) with their tapered ends pointing downwind.
Location near: 4.6°S, 88.3°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Winter
17 April 2006
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.5 meters (~5 feet) per pixel view of a crater in the Terra Cimmeria region of Mars. Several gullies extend from near the top of the crater rim, downslope toward the floor of the crater. Liquid water might have played a role in their genesis.
Location near: 37.7°S, 191.6°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Summer
