Browse All : Mars of California from 2005

Giant Landslide on Iapetus

Description	Giant Landslide on Iapetus
Full Description	A spectacular landslide within the low-brightness region of Iapetus's surface known as Cassini Regio is visible in this image from Cassini. Iapetus is one of the moons of Saturn. The landslide material appears to have collapsed from a scarp 15 kilometers high (9 miles) that forms the rim of an ancient 600 kilometer (375 mile) impact basin. Unconsolidated rubble from the landslide extends halfway across a conspicuous, 120-kilometer diameter (75-mile) flat-floored impact crater that lies just inside the basin scarp. Landslides are common geological phenomena on many planetary bodies, including Earth and Mars. The appearance of this landslide on an icy satellite with low-brightness cratered terrain is reminiscent of landslide features that were observed during NASA's Galileo mission on the Jovian satellite Callisto. The fact that the Iapetus landslide traveled many kilometers from the basin scarp could indicate that the surface material is very fine-grained, and perhaps was fluffed by mechanical forces that allowed the landslide debris to flow extended distances. In this view, north is to the left of the picture and solar illumination is from the bottom of the frame. The image was obtained in visible light with the Cassini spacecraft narrow angle camera on Dec. 31, 2004, at a distance of about 123,400 kilometers (76,677 miles) from Iapetus and at a Sun-Iapetus-spacecraft, or phase, angle of 78 degrees. Resolution achieved in the original image was 740 meters (2,428 feet) per pixel. The image has been contrast-enhanced and magnified by a factor of two to aid visibility. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For images visit the Cassini imaging team home page http://ciclops.org . Credit: NASA/JPL/Space Science Institute
Date	January 7, 2005

Scrutinizing Titan's Surface

Description	Scrutinizing Titan's Surface
Full Description	The six close-up views of Titan's surface shown here are composed of images acquired by the Cassini spacecraft during flybys in October (see Titan Mosaic: October 2004) and December (see Titan Mosaic: December 2004) of 2004. These close-up views illustrate that a variety of processes have shaped the surface of Titan, just as diverse geologic processes are responsible for what we see on Earth's surface. Image (a) shows a prominent bright-dark boundary near the western edge of the Xanadu region which exhibits a sharp, angular edge between the materials. Three bright, discontinuous circles can be seen (two near the top of the image and another near the lower left). These may be large impact craters, the upper two are approximately 30 kilometers (18.6 miles) in diameter and the lower one is approximately 50 kilometers (20 miles) in diameter. Titan's thick atmosphere will screen out small projectiles, but if the surface were as old as Titan itself, it should have many more craters of these sizes. Therefore, Cassini scientists think that, like Earth's surface, Titan's surface has been modified more recently by other geologic processes. However, such processes on Titan may take much longer than on Earth, acting over hundreds of millions of years. Image (b) shows bright features that appear to be streamlined as if were they formed by winds in Titan's atmosphere moving from west to east. The landing site of the Huygens probe is in the upper left corner of this image (see Cassini's View of Titan Landing Site). Image (c) shows a bright feature surrounded by dark material. Several long, dark and narrow lines running through the bright area may be larger examples of the dark channels seen by the Huygens probe (see Mosaic of River Channel and Ridge Area on Titan). These lines are on the order of 2 kilometers (1 mile) wide, and tens of kilometers long. Image (d) shows dark material within the bright area to the west of Xanadu. The linear nature of these features suggests that they may have formed by faulting. They may be dark due to modification by other surface processes occurring on Titan, in the same way that on Earth, fault-lines can be enhanced by erosion and/or deposition of material by water and wind. Image (e) shows brightness variations in the region southeast of the Huygens landing site. The features indicated by arrows exhibit shapes that are similar to drainage patterns seen on Earth and Mars, where the source of the liquid is underground springs rather than rainfall. Image (f) shows a region near the northwestern edge of Xanadu where the boundary between the bright and dark materials is quite complicated. Here some of the bright patches appear as if they represent thin surface plates that have been broken apart and spread apart over underlying dark material. The white bars above each image are 200 kilometers (124 miles) long. Imaging Titan through its thick atmosphere is a challenge, and the narrow, straight lines within the images, are seams between individual images that have not been completely removed. North is to the top of each frame. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org . Credit: NASA/JPL/Space Science Institute.
Date	March 9, 2005

Mars Rover Panorama Shows Vista From 'Lookout' Point

Mars Rover Panorama Shows Vi …

title	Mars Rover Panorama Shows Vista From 'Lookout' Point
date	04.29.2005
description	From a ridgeline vantage point overlooking slopes, valleys and plains, NASA's Mars Exploration Rover Spirit has returned its latest color panorama of the martian landscape. The approximately true color image shows a full 360-degree view from a site informally named "Larry's Lookout," about halfway up "Husband Hill." Dr. Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for the panoramic cameras on both the Spirit and Opportunity Mars rovers, said, "Spirit and the rover team worked hard over many weeks to get to this vantage point along the flanks of Husband Hill. The rugged ridge and valley terrain seen here is similar in some respects to the view seen months earlier at the 'West Spur,' but the chemistry and mineralogy here are significantly different. Specifically, some of the areas seen here amid the outcrop rocks and in places where the subsurface was exposed by the rover wheels contain the highest sulfur abundances ever measured by Spirit." The view includes the summit of Husband Hill about 200 meters (about 660 feet) southward and about 45 meters (about 150 feet) higher. As Spirit continues uphill, scientists are looking for evidence about whether the intensity of water- related alteration increases with elevation or whether there are pockets of more heavily altered rocks and soils scattered throughout the hills. Spirit's panoramic camera took more than 300 individual frames between Feb. 27 and March 2 that are combined into the big picture. Downloading the frames to Earth took several weeks, and processing took additional time. Imaging specialists at Cornell and at NASA's Jet Propulsion Laboratory, Pasadena, Calif., calibrated the color and assembled the image. Spirit and its twin, Opportunity, successfully completed three-month primary missions a year ago. In extended missions since then, they have been exploring at increasing distances from their landing sites. JPL, a division of the California Institute of Technology in Pasadena, manages NASA's Mars Exploration Rover project for NASA's Science Mission Directorate, Washington. Spirit's "Lookout" panorama is also available online at http://www.nasa.gov/vision/universe/solarsystem/mer_main.html [ http://www.nasa.gov/vision/universe/solarsystem/mer_main.html ]and http://marsrovers.jpl.nasa.gov [ http://marsrovers.jpl.nasa.gov/ ] .

Largest Asteroid May Be 'Mini Planet' with Water Ice

Largest Asteroid May Be 'Min …

Title	Largest Asteroid May Be 'Mini Planet' with Water Ice

Mars Reconnaissance Orbiter …

Title	Mars Reconnaissance Orbiter Aerobraking
Description	December 10, 2003 NASA's Mars Reconnaissance Orbiter dips into the thin martian atmosphere to adjust its orbit in this artist's concept illustration. NASA plans to launch this multipurpose spacecraft in August 2005 for arrival at Mars in March 2006. The plans call for controlled use of atmospheric friction in a process called aerobraking for about six months after arrival to change the initial, very elongated orbit into a rounder shape optimal for science operations. Mars Reconnaissance Orbiter is designed to advance our understanding of Mars through detailed observation, to examine potential landing sites for future surface missions and to provide a high-data-rate communications relay for those missions. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Office of Space Science, Washington. JPL's main industrial partner in the project, Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft.
Date	12.10.2003

Mars Reconnaissance Orbiter …

Title	Mars Reconnaissance Orbiter over Nilosyrtis
Description	December 10, 2003 NASA's Mars Reconnaissance Orbiter passes above a portion of the planet called Nilosyrtis Mensae in this artist's concept illustration. NASA plans to launch this multipurpose spacecraft in August 2005 to advance our understanding of Mars through detailed observation, to examine potential landing sites for future surface missions and to provide a high-data-rate communications relay for those missions. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Office of Space Science, Washington. JPL's main industrial partner in the project, Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft.
Date	12.10.2003

Mars Reconnaissance Orbiter …

Title	Mars Reconnaissance Orbiter over Pole
Description	December 10, 2003 NASA's Mars Reconnaissance Orbiter passes over the planet's south polar region in this artist's concept illustration. NASA plans to launch this multipurpose spacecraft in August 2005 to advance our understanding of Mars through detailed observation, to examine potential landing sites for future surface missions and to provide a high-data-rate communications relay for those missions. The orbiter's shallow radar experiment, one of six science instruments on board, is designed to probe the internal structure of Mars' polar ice caps, as well as to gather information planet-wide about underground layers of ice, rock and, perhaps, liquid water that might be accessible from the surface. Phobos, one of Mars' two moons, appears in the upper left corner of the illustration NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Office of Space Science, Washington. JPL's main industrial partner in the project, Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft. The Italian Space Agency is providing the radar instrument.
Date	12.10.2003

This picture shows the Mars Express orbiter as a white, wavy, slanted streak centered against a vast, deep black background. The lines of the spacecraft make it appear somewhat like a jagged, three-inch worm in space.

Mars Express Seen by Mars Gl …

title	Mars Express Seen by Mars Global Surveyor, This picture shows the Mars Express orbiter as a white, wavy, slanted streak centered against a vast, deep black background. The lines of the spacecraft make it appear somewhat like a jagged, three-inch worm in space.
Description	This picture of the European Space Agency's Mars Express spacecraft by the Mars Orbiter Camera on NASA's Mars Global Surveyor is from the first successful imaging of any spacecraft orbiting Mars by another spacecraft orbiting Mars. The picture is a composite of two views of Mars Express that Mars Orbiter Camera acquired on April 20, 2005, from distances of about 250 and 370 kilometers (155 and 229 miles). Owing to the large distance between Mars Global Surveyor and Mars Express when the two views could be acquired and to a substantial cross-track component of apparent motion for which no correction could be made, Mars Express appears in the image as a narrow blur rather than as a well-defined spacecraft. It appears in the image to be about 1.5 meters in the small dimension and 15 meters in the long dimension, which is consistent with the viewing distance, pixel scale, and encounter geometry. The components of Mars Express when viewed from the same angle as this image can be seen in an artist's rendition http://photojournal.jpl.nasa.gov/figures/PIA07944_fig1.jpg and an annotated rendition http://photojournal.jpl.nasa.gov/figures/PIA07944_fig2.jpg of the spacecraft. Mars Express was launched on June 3, 2003, and reached Mars on Dec. 25, 2003. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washingon, D.C. Credit: NASA/JPL/MSSS

Scarp at Head of Chasma Bore …

title	Scarp at Head of Chasma Boreale
Description	This view shows sharp detail of a scarp at the head of Chasma Boreale, a large trough cut by erosion into the martian north polar cap and the layered material beneath the ice cap. The picture is a mosaic of two images acquired in January 2005 by the Mars Orbiter Camera on NASA's Mars Global Surveyor, using a resolution-enhancing technique called "compensated pitch and roll targeted observation." The camera team considers this the best pair of images yet acquired using that technique. During each northern summer on Mars, there occurs a narrow window in time of two to three months when conditions are ideal to image the north polar cap at high resolution. Throughout this period, the atmosphere is generally clear over the cap, and the seasonal carbon-dioxide frost from the previous winter and spring has sublimed away, permitting a good view of the surface geology. The two images in this mosaic were acquired during this brief period during the most recent northern summer. Within a few weeks of when these images were acquired, dust storm activity picked up in the north polar region, making the atmosphere too dusty to obtain any more detailed views until late 2006. Chasma Boreale is cut into the layered material that lies beneath the water ice of the north polar cap. For decades, these layered materials were assumed to consist of a mixture of ice and dust. Mars Orbiter Camera images obtained in 1999 and 2001 began to show that some of the layers are a source for windblown sand. The science objective for the two images shown in this mosaic was to look for boulders in the debris shed from the steep slopes cut into the north polar layers by Chasma Boreale. Finding boulders would imply that the layers that are the most resistant to erosion in the polar region are as competent as solid rock, perhaps giving a new insight into the nature of the polar layered materials. The pictured site is near 84.8 degrees north latitude, 356.4 degrees west longitude. Examination of the high-resolution mosaic shows that there are indeed some large boulders that have eroded out of the layered materials and rolled down the slopes. It is possible, therefore, that the north polar layers are not simply a mixture of ice, dust, and sand. Some layers may actually be rock, cemented by minerals rather than by ice. Alternatively, if the materials are cemented by ice, then a future high-resolution view might show that the boulders have become smaller over time. In addition to the observation of boulders eroding out of the polar layered materials, the mosaic also helps confirm that dark sand is eroding out of the polar layered materials, and that there are three different groups of layers under the polar ice. The upper unit is light-toned, finely layered, and more resistant to erosion (more competent, less easily destroyed by erosion) than the middle unit, which is rich in dark sand but also has several shelf-forming layers in it. Finally, below the dark, sandy layer is a third unit, that is light-toned and has a different appearance relative to the other two units. Some of its layers have surfaces that have been broken by shallow fractures into polygonal and linear forms, also implying that they are hard, resistant rock. The level of detail seen in the mosaic was made possible by the development of a resolution-enhancing technique for using the Mars Orbiter Camera. During 2003 and 2004, the Mars Orbiter Camera operations team at Malin Space Science Systems, San Diego, Calif., worked closely with the Mars Global Surveyor operations teams at the Jet Propulsion Laboratory, Pasadena, Calif., and Lockheed Martin Space Systems, Denver, Colo., to develop a new technique in which the spacecraft does a maneuver that permits the camera to acquire images at a higher spatial resolution than normal. Usually, Mars Orbiter Camera images have a resolution of about 1.5 meters (5 feet) per pixel, and the camera can be commanded to acquire lower resolution data when desired. To obtain a higher resolution, the whole spacecraft must be pitched at such a rate that the camera over-samples its view of the martian surface in the down-track direction. Called compensated pitch and roll targeted observation, or cPROTO, this technique allows Mars Orbiter Camera to obtain images that have a resolution of about 50 centimeters (20 inches) per pixel in the down-track direction, and 150 centimeters (5 feet) per pixel in the cross-track dimension. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington Credit: NASA/JPL/MSSS

New Gullies on Martian Sand …

title	New Gullies on Martian Sand Dune
Description	One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (insert MOC2-1212a), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that, these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (insert MOC2-1212c) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (insert MOC2-1212d). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington. Credit: NASA/JPL/MSSS/ASU

Moriba Jah Awaits Navigation Information

Moriba Jah Awaits Navigation …

title	Moriba Jah Awaits Navigation Information
Description	Forty minutes after launch, the navigation team hits full throttle, locating the exact trajectory of the Mars Reconnaissance Orbiter. Moriba Jah awaits the most updated information from the Goldstone, California Deep Space Network tracking station while in the Navigation Operations room at Jet Propulsion Laboratory on August 12, 2005. Credit: NASA/JPL

Flight Engineering Team Members Enjoy the Launch

Flight Engineering Team Memb …

title	Flight Engineering Team Members Enjoy the Launch
Description	For over five years, Flight Engineering Team members have dedicated tireless hours to creating the Mars Reconnaissance Orbiter. On August 12, 2005, Kyle Martin, Peter Xaypraseuth, and David Skulsky take five minutes to experience the thrill of watching their spacecraft launch from Kennedy Space Center in Florida via TV screens in the Mission Support Area at JPL in California. Credit: NASA/JPL

Mars Reconnaissance Orbiter Taking Shape

Mars Reconnaissance Orbiter …

title	Mars Reconnaissance Orbiter Taking Shape
Description	Lockheed Martin Space Systems engineer Terry Kampmann (left) and lead technician Jack Farmerie work on assembly and test of NASA's Mars Reconnaissance Orbiter spacecraft bus in a cleanroom at the company's Denver facility. In coming months, the orbiter's science instruments will be integrated and tested, followed by environmental testing of the completed spacecraft. Launch of Mars Reconnaissance Orbiter is scheduled for August 2005. The Mars Reconnaissance Orbiter project is managed for the NASA Science Mission Directorate, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, is prime contractor for the project. Credit: NASA/JPL/Lockheed Martin/Pat Corkery

Mars Odyssey Seen by Mars Global Surveyor (3-D)

Mars Odyssey Seen by Mars Gl …

title	Mars Odyssey Seen by Mars Global Surveyor (3-D)
Description	This stereoscopic picture of NASA's Mars Odyssey spacecraft was created from two views of that spacecraft taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars ever taken by another spacecraft orbiting Mars. Mars Global Surveyor acquired this image of Mars Odyssey on April 21, 2005. The stereoscopic picture combines one view captured while the two orbiters were 90 kilometers (56 miles) apart with a second view captured from a slightly different angle when the two orbiters were 135 kilometers (84 miles) apart. For proper viewing, the user needs "3-D" glasses with red over the left eye and blue over the right eye. The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C. Credit: NASA/JPL/MSSS

Mars Reconnaissance Orbiter …

PIA04918

Title	Mars Reconnaissance Orbiter over Pole
Original Caption Released with Image	December 10, 2003 NASA's Mars Reconnaissance Orbiter passes over the planet's south polar region in this artist's concept illustration. NASA plans to launch this multipurpose spacecraft in August 2005 to advance our understanding of Mars through detailed observation, to examine potential landing sites for future surface missions and to provide a high-data-rate communications relay for those missions. The orbiter's shallow radar experiment, one of six science instruments on board, is designed to probe the internal structure of Mars' polar ice caps, as well as to gather information planet-wide about underground layers of ice, rock and, perhaps, liquid water that might be accessible from the surface. Phobos, one of Mars' two moons, appears in the upper left corner of the illustration NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Office of Space Science, Washington. JPL's main industrial partner in the project, Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft. The Italian Space Agency is providing the radar instrument.

Mars Reconnaissance Orbiter over Nilosyrtis

Mars Reconnaissance Orbiter …

PIA04916

Title	Mars Reconnaissance Orbiter over Nilosyrtis
Original Caption Released with Image	December 10, 2003 NASA's Mars Reconnaissance Orbiter passes above a portion of the planet called Nilosyrtis Mensae in this artist's concept illustration. NASA plans to launch this multipurpose spacecraft in August 2005 to advance our understanding of Mars through detailed observation, to examine potential landing sites for future surface missions and to provide a high-data-rate communications relay for those missions. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Office of Space Science, Washington. JPL's main industrial partner in the project, Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft.

Mars Reconnaissance Orbiter …

PIA04917

Title	Mars Reconnaissance Orbiter Aerobraking
Original Caption Released with Image	December 10, 2003 NASA's Mars Reconnaissance Orbiter dips into the thin martian atmosphere to adjust its orbit in this artist's concept illustration. NASA plans to launch this multipurpose spacecraft in August 2005 for arrival at Mars in March 2006. The plans call for controlled use of atmospheric friction in a process called aerobraking for about six months after arrival to change the initial, very elongated orbit into a rounder shape optimal for science operations. Mars Reconnaissance Orbiter is designed to advance our understanding of Mars through detailed observation, to examine potential landing sites for future surface missions and to provide a high-data-rate communications relay for those missions. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter Project for the NASA Office of Space Science, Washington. JPL's main industrial partner in the project, Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft.

Three Years of Monitoring Mars' Atmospheric Dust (Animation)

Three Years of Monitoring Ma …

PIA04297

Sol (our sun)

Thermal Emission Spectromete …

Title	Three Years of Monitoring Mars' Atmospheric Dust (Animation)
Original Caption Released with Image	[ http://photojournal.jpl.nasa.gov/archive/PIA04297.mpeg ] Animation This movie shows the daily abundance of dust in the martian atmosphere over a period of three full martian years, from April 1999 through February 2005. The Thermal Emission Spectrometer instrument on NASA's Mars Global Surveyor orbiter has been tracking the weather on Mars for six years. The infrared spectrum observed by this instrument yields information about the spectral properties of the dust and the temperature of the atmosphere. These two properties can then be used to derive how much dust is in the atmosphere. Of particular interest are large regional and global dust storms that occur during summer in the southern hemisphere each Mars year. The 2001 storm was by far the largest, lasting over six months (June to October, 2001) and covering the entire planet. The storms in the other two Mars years shown here were much smaller and never covered the planet. The most recent storm season (June 2003 through January 2005) actually had two separate storms, one in June and a second in December. Unlike most large martian dust storms that start in the southern hemisphere, the December storm began in the north and swept toward the equator. Between storms the atmosphere becomes quite clear, with much smaller dust storms scattered throughout the year and over the planet. Seasons on Mars are determined by the position of Mars in its orbit around the Sun. The position is measured in degrees of solar longitude (Ls) around the orbit, beginning at 0 degrees Ls at the northern spring equinox, progressing to 90 degrees Ls at the start of northern summer, 180 degrees Ls at the fall equinox, 270 degrees Ls at the start of northern winter, and finally back to 360 degrees, or 0 degrees, Ls at the spring equinox. Dust abundance is measured as opacity (tau), with values of 0 tau representing a completely clear atmosphere, and values of 2 indicating that it is nearly impossible to see through to the surface. The Thermal Emission Spectrometer is operated by a team led at Arizona State University, Tempe. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington.

New Gullies on Martian Sand …

PIA04290

Sol (our sun)

Mars Orbiter Camera

Title	New Gullies on Martian Sand Dune
Original Caption Released with Image	), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2

New Gullies on Martian Sand …

PIA04290

Sol (our sun)

Mars Orbiter Camera

Title	New Gullies on Martian Sand Dune
Original Caption Released with Image	), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2

New Gullies on Martian Sand …

PIA04290

Sol (our sun)

Mars Orbiter Camera

Title	New Gullies on Martian Sand Dune
Original Caption Released with Image	), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2

New Gullies on Martian Sand …

PIA04290

Sol (our sun)

Mars Orbiter Camera

Title	New Gullies on Martian Sand Dune
Original Caption Released with Image	), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2

New Gullies on Martian Sand …

PIA04290

Sol (our sun)

Mars Orbiter Camera

Title	New Gullies on Martian Sand Dune
Original Caption Released with Image	), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (figure 3) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (figure 4). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington., One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images (figure 1) from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (figure 2

Mars Reconnaissance Orbiter …

PIA06756

Title	Mars Reconnaissance Orbiter Taking Shape
Original Caption Released with Image	Lockheed Martin Space Systems engineer Terry Kampmann (left) and lead technician Jack Farmerie work on assembly and test of NASA's Mars Reconnaissance Orbiter spacecraft bus in a cleanroom at the company's Denver facility. In coming months, the orbiter's science instruments will be integrated and tested, followed by environmental testing of the completed spacecraft. Launch of Mars Reconnaissance Orbiter is scheduled for August 2005. The Mars Reconnaissance Orbiter project is managed for the NASA Science Mission Directorate, Washington, by the Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena. Lockheed Martin Space Systems, Denver, is prime contractor for the project.

Mars Odyssey Seen by Mars Gl …

PIA07943

Mars Orbiter Camera

Title	Mars Odyssey Seen by Mars Global Surveyor (3-D)
Original Caption Released with Image	This stereoscopic picture of NASA's Mars Odyssey spacecraft was created from two views of that spacecraft taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars. Mars Global Surveyor acquired this image of Mars Odyssey on April 21, 2005. The stereoscopic picture combines one view captured while the two orbiters were 90 kilometers (56 miles) apart with a second view captured from a slightly different angle when the two orbiters were 135 kilometers (84 miles) apart. For proper viewing, the user needs "3-D" glasses with red over the left eye and blue over the right eye. The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C.

Mars Odyssey from Two Distances in One Image

Mars Odyssey from Two Distan …

PIA07941

Mars Orbiter Camera

Title	Mars Odyssey from Two Distances in One Image
Original Caption Released with Image	Figure 1: Why There are Two Images of Odyssey NASA's Mars Odyssey spacecraft appears twice in the same frame in this image from the Mars Orbiter Camera aboard NASA's Mars Global Surveyor. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars. Mars Global Surveyor and Mars Odyssey are both in nearly circular, near-polar orbits. Odyssey is in an orbit slightly higher than that of Global Surveyor in order to preclude the possibility of a collision. However, the two spacecraft occasionally come as close together as 15 kilometers (9 miles). The images were obtained by the Mars Global Surveyor operations teams at Lockheed Martin Space System, Denver, JPL and Malin Space Science Systems. The two views of Mars Odyssey in this image were acquired a little under 7.5 seconds apart as Odyssey receded from a close flyby of Mars Global Surveyor. The geometry of the flyby (see Figure 1) and the camera's way of acquiring an image line-by-line resulted in the two views of Odyssey in the same frame. The first view (right) was taken when Odyssey was about 90 kilometers (56 miles) from Global Surveyor and moving more rapidly than Global Surveyor was rotating, as seen from Global Surveyor. A few seconds later, Odyssey was farther away -- about 135 kilometers (84 miles) -- and appeared to be moving more slowly. In this second view of Odyssey (left), the Mars Orbiter Camera's field-of-view overtook Odyssey. The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C.

Mars Odyssey from Two Distan …

PIA07941

Mars Orbiter Camera

Title	Mars Odyssey from Two Distances in One Image
Original Caption Released with Image	Figure 1: Why There are Two Images of Odyssey NASA's Mars Odyssey spacecraft appears twice in the same frame in this image from the Mars Orbiter Camera aboard NASA's Mars Global Surveyor. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars. Mars Global Surveyor and Mars Odyssey are both in nearly circular, near-polar orbits. Odyssey is in an orbit slightly higher than that of Global Surveyor in order to preclude the possibility of a collision. However, the two spacecraft occasionally come as close together as 15 kilometers (9 miles). The images were obtained by the Mars Global Surveyor operations teams at Lockheed Martin Space System, Denver, JPL and Malin Space Science Systems. The two views of Mars Odyssey in this image were acquired a little under 7.5 seconds apart as Odyssey receded from a close flyby of Mars Global Surveyor. The geometry of the flyby (see Figure 1) and the camera's way of acquiring an image line-by-line resulted in the two views of Odyssey in the same frame. The first view (right) was taken when Odyssey was about 90 kilometers (56 miles) from Global Surveyor and moving more rapidly than Global Surveyor was rotating, as seen from Global Surveyor. A few seconds later, Odyssey was farther away -- about 135 kilometers (84 miles) -- and appeared to be moving more slowly. In this second view of Odyssey (left), the Mars Orbiter Camera's field-of-view overtook Odyssey. The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C.

Mars Odyssey Seen by Mars Global Surveyor

Mars Odyssey Seen by Mars Gl …

PIA07942

Mars Orbiter Camera

Title	Mars Odyssey Seen by Mars Global Surveyor
Original Caption Released with Image	This view is an enlargement of an image of NASA's Mars Odyssey spacecraft taken by the Mars Orbiter Camera aboard NASA's Mars Global Surveyor while the two spacecraft were about 90 kilometers (56 miles) apart. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars. Mars Global Surveyor and Mars Odyssey are both in nearly circular, near-polar orbits. Odyssey is in an orbit slightly higher than that of Global Surveyor in order to preclude the possibility of a collision. However, the two spacecraft occasionally come as close together as 15 kilometers (9 miles). The images were obtained by the Mars Global Surveyor operations teams at Lockheed Martin Space System, Denver, JPL and Malin Space Science Systems The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. The components of Mars Odyssey when viewed from the same angle as this image can be seen in a computer drawing and an annotated computer drawing, of Odyssey. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C.

Mars Odyssey Seen by Mars Gl …

PIA07942

Mars Orbiter Camera

Title	Mars Odyssey Seen by Mars Global Surveyor
Original Caption Released with Image	This view is an enlargement of an image of NASA's Mars Odyssey spacecraft taken by the Mars Orbiter Camera aboard NASA's Mars Global Surveyor while the two spacecraft were about 90 kilometers (56 miles) apart. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars. Mars Global Surveyor and Mars Odyssey are both in nearly circular, near-polar orbits. Odyssey is in an orbit slightly higher than that of Global Surveyor in order to preclude the possibility of a collision. However, the two spacecraft occasionally come as close together as 15 kilometers (9 miles). The images were obtained by the Mars Global Surveyor operations teams at Lockheed Martin Space System, Denver, JPL and Malin Space Science Systems The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. The components of Mars Odyssey when viewed from the same angle as this image can be seen in a computer drawing and an annotated computer drawing, of Odyssey. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C.

Mars Odyssey Seen by Mars Gl …

PIA07942

Mars Orbiter Camera

Title	Mars Odyssey Seen by Mars Global Surveyor
Original Caption Released with Image	This view is an enlargement of an image of NASA's Mars Odyssey spacecraft taken by the Mars Orbiter Camera aboard NASA's Mars Global Surveyor while the two spacecraft were about 90 kilometers (56 miles) apart. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars taken by another spacecraft orbiting Mars. Mars Global Surveyor and Mars Odyssey are both in nearly circular, near-polar orbits. Odyssey is in an orbit slightly higher than that of Global Surveyor in order to preclude the possibility of a collision. However, the two spacecraft occasionally come as close together as 15 kilometers (9 miles). The images were obtained by the Mars Global Surveyor operations teams at Lockheed Martin Space System, Denver, JPL and Malin Space Science Systems The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. The components of Mars Odyssey when viewed from the same angle as this image can be seen in a computer drawing and an annotated computer drawing, of Odyssey. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C.

Scarp at Head of Chasma Bore …

PIA04296

Sol (our sun)

Mars Orbiter Camera

Title	Scarp at Head of Chasma Boreale
Original Caption Released with Image	This view shows sharp detail of a scarp at the head of Chasma Boreale, a large trough cut by erosion into the martian north polar cap and the layered material beneath the ice cap. The picture is a mosaic of two images acquired in January 2005 by the Mars Orbiter Camera on NASA's Mars Global Surveyor, using a resolution-enhancing technique called "compensated pitch and roll targeted observation." The camera team considers this the best pair of images yet acquired using that technique. During each northern summer on Mars, there occurs a narrow window in time of two to three months when conditions are ideal to image the north polar cap at high resolution. Throughout this period, the atmosphere is generally clear over the cap, and the seasonal carbon-dioxide frost from the previous winter and spring has sublimed away, permitting a good view of the surface geology. The two images in this mosaic were acquired during this brief period during the most recent northern summer. Within a few weeks of when these images were acquired, dust storm activity picked up in the north polar region, making the atmosphere too dusty to obtain any more detailed views until late 2006. Chasma Boreale is cut into the layered material that lies beneath the water ice of the north polar cap. For decades, these layered materials were assumed to consist of a mixture of ice and dust. Mars Orbiter Camera images obtained in 1999 and 2001 began to show that some of the layers are a source for windblown sand. The science objective for the two images shown in this mosaic was to look for boulders in the debris shed from the steep slopes cut into the north polar layers by Chasma Boreale. Finding boulders would imply that the layers that are the most resistant to erosion in the polar region are as competent as solid rock, perhaps giving a new insight into the nature of the polar layered materials. The pictured site is near 84.8 degrees north latitude, 356.4 degrees west longitude. Examination of the high-resolution mosaic shows that there are indeed some large boulders that have eroded out of the layered materials and rolled down the slopes. It is possible, therefore, that the north polar layers are not simply a mixture of ice, dust, and sand. Some layers may actually be rock, cemented by minerals rather than by ice. Alternatively, if the materials are cemented by ice, then a future high-resolution view might show that the boulders have become smaller over time. In addition to the observation of boulders eroding out of the polar layered materials, the mosaic also helps confirm that dark sand is eroding out of the polar layered materials, and that there are three different groups of layers under the polar ice. The upper unit is light-toned, finely layered, and more resistant to erosion (more competent, less easily destroyed by erosion) than the middle unit, which is rich in dark sand but also has several shelf-forming layers in it. Finally, below the dark, sandy layer is a third, unit that is light-toned and has a different appearance relative to the other two units. Some of its layers have surfaces that have been broken by shallow fractures into polygonal and linear forms, also implying that they are hard, resistant rock. The level of detail seen in the mosaic was made possible by the development of a resolution-enhancing technique for using the Mars Orbiter Camera. During 2003 and 2004, the Mars Orbiter Camera operations team at Malin Space Science Systems, San Diego, Calif., worked closely with the Mars Global Surveyor operations teams at the Jet Propulsion Laboratory, Pasadena, Calif., and Lockheed Martin Space Systems, Denver, Colo., to develop a new technique in which the spacecraft does a maneuver that permits the camera to acquire images at a higher spatial resolution than normal. Usually, Mars Orbiter Camera images have a resolution of about 1.5 meters (5 feet) per pixel, and the camera can be commanded to acquire lower resolution data when desired. To obtain a higher resolution, the whole spacecraft must be pitched at such a rate that the camera over-samples its view of the martian surface in the down-track direction. Called compensated pitch and roll targeted observation, or cPROTO, this technique allows Mars Orbiter Camera to obtain images that have a resolution of about 50 centimeters (20 inches) per pixel in the down-track direction, and 150 centimeters (5 feet) per pixel in the cross-track dimension. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington.

Depth-to-Ice Map of an Arctic Site on Mars

Depth-to-Ice Map of an Arcti …

PIA09335

Sol (our sun)

Thermal Emission Imaging Sys …

Title	Depth-to-Ice Map of an Arctic Site on Mars
Original Caption Released with Image	Color coding in this map of a far-northern site on Mars indicates the change in nighttime ground-surface temperature between summer and fall. This site, like most of high-latitude Mars, has water ice mixed with soil near the surface. The ice is probably in a rock-hard frozen layer beneath a few centimeters or inches of looser, dry soil. The amount of temperature change at the surface likely corresponds to how close to the surface the icy material lies. The dense, icy layer retains heat better than the looser soil above it, so where the icy layer is closer to the surface, the surface temperature changes more slowly than where the icy layer is buried deeper. On the map, areas of the surface that cooled more slowly between summer and autumn (interpreted as having the ice closer to the surface) are coded blue and green. Areas that cooled more quickly (interpreted as having more distance to the ice) are coded red and yellow. The depth to the top of the icy layer estimated from these observations, as little as 5 centimeters (2 inches), matches modeling of where it would be if Mars has an active cycle of water being exchanged by diffusion between atmospheric water vapor and subsurface water ice. This map and its interpretation are in a May 3, 2007, report in the journal "Nature", by Joshua Bandfield of Arizona State University, Tempe. The Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter collected the data presented in the map. The site is centered near 67.5 degrees north latitude, 132 degrees east longitude, in the Martian arctic plains called Vastitas Borealis. It was formerly a candidate landing site for NASA's Phoenix Mars Lander mission. This site is within the portion of the planet where, in 2002, the Gamma Ray Spectrometer suite of instruments on Mars Odyssey found evidence for water ice lying just below the surface. The information from the Gamma Ray Spectrometer is averaged over patches of ground hundreds of kilometers or miles wide. The information from the Thermal Emission Imaging System allows more than 100-fold higher resolution in mapping variations in the depth to ice. The Thermal Emission Imaging System observed the site in infrared wavelengths during night time, providing surface-temperature information, once on March 13, 2005, during summer in Mars' northern hemisphere, and again on April 8, 2005, during autumn there. The colors on this map signify relative differences in how much the surface temperature changed between those two observations. Blue indicates the locations with the least change. Red indicates areas with most change. Modeling provides estimates that the range of temperature changes shown in this map corresponds to a range in depth-to-ice of 5 centimeters (2 inches) to more than 18 centimeters (more than 7 inches). The sensitivity of this method for estimating the depth is not good for depths greater than about 20 centimeters (8 inches). The temperature-change data are overlaid on a mosaic of black-and-white, daytime images taken in visible-light wavelengths by the same camera, providing information about shapes in the landscape. The 10-kilometer scale bar is 6.2 miles long. NASA's Jet Propulsion Laboratory manages the Mars Odyssey mission for NASA's Science Mission Directorate, Washington, D.C. The Thermal Emission Imaging System was developed by Arizona State University in collaboration with Raytheon Santa Barbara Remote Sensing. Lockheed Martin Space Systems, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images

Second of Two Fresh Impact C …

PIA09024

Sol (our sun)

Mars Orbiter Camera

Title	Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images
Original Caption Released with Image	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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09023 ] or MOC2-1614 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site11/index.html ]). 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) [ http://themis.asu.edu/ ] 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 [ http://www.msss.com/mgs/moc/index.html ].

Second of Two Fresh Impact C …

PIA09024

Sol (our sun)

Mars Orbiter Camera

Title	Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images
Original Caption Released with Image	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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09023 ] or MOC2-1614 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site11/index.html ]). 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) [ http://themis.asu.edu/ ] 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 [ http://www.msss.com/mgs/moc/index.html ].

Second of Two Fresh Impact C …

PIA09024

Sol (our sun)

Mars Orbiter Camera

Title	Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images
Original Caption Released with Image	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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09023 ] or MOC2-1614 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site11/index.html ]). 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) [ http://themis.asu.edu/ ] 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 [ http://www.msss.com/mgs/moc/index.html ].

Second of Two Fresh Impact C …

PIA09024

Sol (our sun)

Mars Orbiter Camera

Title	Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images
Original Caption Released with Image	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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09023 ] or MOC2-1614 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site11/index.html ]). 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) [ http://themis.asu.edu/ ] 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 [ http://www.msss.com/mgs/moc/index.html ].

Second of Two Fresh Impact C …

PIA09024

Sol (our sun)

Mars Orbiter Camera

Title	Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images
Original Caption Released with Image	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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09023 ] or MOC2-1614 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site11/index.html ]). 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) [ http://themis.asu.edu/ ] 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 [ http://www.msss.com/mgs/moc/index.html ].

Second of Two Fresh Impact C …

PIA09024

Sol (our sun)

Mars Orbiter Camera

Title	Second of Two Fresh Impact Crater Sites With "Before" and "After" Narrow Angle Mars Orbiter Camera Images
Original Caption Released with Image	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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09023 ] or MOC2-1614 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site11/index.html ]). 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) [ http://themis.asu.edu/ ] 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 [ http://www.msss.com/mgs/moc/index.html ].

New Gully Deposit in a Crater in Terra Sirenum

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

New Gully Deposit in a Crate …

PIA09027

Sol (our sun)

Mars Orbiter Camera

Title	New Gully Deposit in a Crater in Terra Sirenum
Original Caption Released with Image	Has liquid water flowed on Mars in this decade? 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, 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 [ http://www.msss.com/mgs/moc/index.html ]., 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

Procedure for Finding New Impact Sites on Mars Using the Mars Global Surveyor Mars Orbiter Camera

Procedure for Finding New Im …

PIA09021

Sol (our sun)

Mars Orbiter Camera

Title	Procedure for Finding New Impact Sites on Mars Using the Mars Global Surveyor Mars Orbiter Camera
Original Caption Released with Image	), 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, 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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09020 ] or MOC2-1611 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site1/index.html ], 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) [ http://themis.asu.edu/ ], and Mars Express High Resolution Stereo Camera (HRSC) [ http://berlinadmin.dlr.de/Missions/express/indexeng.shtml ], 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 [ http://www.msss.com/mgs/moc/index.html ].

Procedure for Finding New Im …

PIA09021

Sol (our sun)

Mars Orbiter Camera

Title	Procedure for Finding New Impact Sites on Mars Using the Mars Global Surveyor Mars Orbiter Camera
Original Caption Released with Image	), 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, 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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09020 ] or MOC2-1611 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site1/index.html ], 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) [ http://themis.asu.edu/ ], and Mars Express High Resolution Stereo Camera (HRSC) [ http://berlinadmin.dlr.de/Missions/express/indexeng.shtml ], 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 [ http://www.msss.com/mgs/moc/index.html ].

Procedure for Finding New Im …

PIA09021

Sol (our sun)

Mars Orbiter Camera

Title	Procedure for Finding New Impact Sites on Mars Using the Mars Global Surveyor Mars Orbiter Camera
Original Caption Released with Image	), 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, 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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09020 ] or MOC2-1611 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site1/index.html ], 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) [ http://themis.asu.edu/ ], and Mars Express High Resolution Stereo Camera (HRSC) [ http://berlinadmin.dlr.de/Missions/express/indexeng.shtml ], 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 [ http://www.msss.com/mgs/moc/index.html ].

Procedure for Finding New Im …

PIA09021

Sol (our sun)

Mars Orbiter Camera

Title	Procedure for Finding New Impact Sites on Mars Using the Mars Global Surveyor Mars Orbiter Camera
Original Caption Released with Image	), 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, 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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09020 ] or MOC2-1611 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site1/index.html ], 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) [ http://themis.asu.edu/ ], and Mars Express High Resolution Stereo Camera (HRSC) [ http://berlinadmin.dlr.de/Missions/express/indexeng.shtml ], 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 [ http://www.msss.com/mgs/moc/index.html ].

Procedure for Finding New Im …

PIA09021

Sol (our sun)

Mars Orbiter Camera

Title	Procedure for Finding New Impact Sites on Mars Using the Mars Global Surveyor Mars Orbiter Camera
Original Caption Released with Image	), 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, 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 [ http://photojournal.jpl.nasa.gov/catalog/PIA09020 ] or MOC2-1611 [ http://www.msss.com/mars_images/moc/2006/12/06/craters/site1/index.html ], 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) [ http://themis.asu.edu/ ], and Mars Express High Resolution Stereo Camera (HRSC) [ http://berlinadmin.dlr.de/Missions/express/indexeng.shtml ], 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 [ http://www.msss.com/mgs/moc/index.html ].

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