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Earth and Mars of Jet Propulsion Laboratory (JPL) and Washington
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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 |
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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 |
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Eyes on Iapetus!
| Description |
This map of the surface of Iapetus, generated from images taken by NASA's Cassini and Voyager spacecraft, illustrates the imaging coverage planned for Cassini's very close flyby of the two-toned moon on Sept. 10, 2007. |
| Full Description |
This map of the surface of Iapetus, generated from images taken by NASA's Cassini and Voyager spacecraft, illustrates the imaging coverage planned for Cassini's very close flyby of the two-toned moon on Sept. 10, 2007. This flyby will be Cassini's only close approach to Iapetus (1,468 kilometers, or 912 miles across) during the entire planned mission. At closest approach, Cassini will be 1,640 kilometers (1,020 miles) above the surface of Iapetus. The spacecraft will pass the moon at a speed of about 2.4 kilometers (1.5 miles) per second--a relatively leisurely pace that will allow plenty of time for the scientific instruments on board to collect massive amounts of data. Cassini's previous encounter with Iapetus, on Dec. 31, 2004, focused on the mysterious territory in Cassini Regio, the region blanketed by dark material that covers most of the moon's leading hemisphere. The upcoming encounter will be primarily concerned with terrain farther west, in the important transition region between Cassini Regio and the bright trailing hemisphere. Scientists hope to learn a great deal more about the composition of the materials that compose the surface of Iapetus during this encounter. Another area of focus is the large equatorial ridge that overlies the moon's equator (see Encountering Iapetus). The ridge reaches 20 kilometers (12 miles) high in some places and extends over 1,300 kilometers (808 miles) in length. No other moon in the solar system has a geological feature like this striking ridge. The tallest mountains on the ridge rival Olympus Mons on Mars, which is approximately three times the height of Mt. Everest. Such giant mountains are a surprising feature for such a small body as Iapetus, which is nearly five times smaller than Mars and nearly nine times smaller than Earth. Colored lines on the map enclose regions that will be covered at different imaging scales as Cassini encounters Iapetus. The highest expected resolution of Cassini images from this flyby is about 20 meters (65 feet) per pixel--significantly higher than the 2004 encounter. 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 operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org . *Credit:* NASA/JPL/Space Science Institute |
| Date |
September 5, 2007 |
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Pathfinder Panorama
| title |
Pathfinder Panorama |
| description |
This is a more recent 'geometrically improved, color enhanced' version of the 360-degree 'Gallery Pan', the first contiguous, uniform panorama taken by the Imager for Mars (IMP) over the course of Sols 8, 9, and 10. Different regions were imaged at different times over the three Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama. In this version of the panorama, much of the discontinuity that was due to parallax has been corrected, particularly along thelower tiers of the mosaic containing the Lander features. Distortiondue to a 2.5 degree tilt in the IMP camera mast has been removed. The IMP is a stereo imaging system that, in its fully deployed configuration, stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters. The IMP has color capability provided by 24 selectable filters -- twelve filters per 'eye'. Its red, green, and blue filters were used to take this panorama. The three color images were first digitally balanced according to the transmittance capabilities of a specific high-definition TV device at JPL, and then enhanced via changes to saturation and intensity while retaining the hue. A threshold was applied to avoid changes to the sky. An MTF filter was applied to sharpen feature edges. At left is a Lander petal and a metallic mast which is a portion of the low-gain antenna. On the horizon the double 'Twin Peaks' are visible, about 1-2 kilometers away. The rock 'Couch' is the dark, curved rock at right of Twin Peaks. Another Lander petal is at left-center, showing the fully deployed forward ramp at far left, and rear ramp at right, which rover Sojourner used to descend to the surface of Mars on July 5. Immediately to the left of the rear ramp is the rock 'Barnacle Bill', which scientistsfound be andesitic, possibly indicating that it is a volcanic rock (a true andesite) or a physical mixture of particles. Just beyond Barnacle Bill, rover tracks lead to Sojourner, shown using its Alpha ProtonX-Ray Spectrometer (APXS) instrument to study the large rock 'Yogi'. Yogi, low in quartz content, appears to be more primitive than Barnacle Bill, and appears more like the common basalts found on Earth. The tracks and circular pattern in the soil leading up to Yogi werepart of Sojourner's soil mechanics experiments, in which varying amounts of pressure were applied to the wheels in order to determine physical properties of the soil. During its traverse to Yogi the roverstirred the soil and exposed material from several centimeters indepth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer, the wheels dug particularly deeply and exposed white material. Spectra of this white material show it is virtually identical to the rock 'Scooby Doo', and such white material may underlie much of the site. Deflated airbags are visible at the perimeter of all three Lander petals. Mars Pathfinder was the second in NASA's Discovery, program of low-costspacecraft with highly focused science goals. The Jet PropulsionLaboratory, Pasadena, CA, developed and manages the Mars Pathfindermission for NASA's Office of Space Science, Washington, D.C. JPL is anoperating division of the California Institute of Technology (Caltech).The IMP was developed by the University of Arizona Lunar and PlanetaryLaboratory under contract to JPL. Peter Smith is the Principal Investigator. *Image Credit*: NASA |
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Mars Rover Panorama Shows Vi
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| 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/ ] . |
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Newly Deployed Sojourner Rov
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| title |
Newly Deployed Sojourner Rover |
| description |
This 8-image mosaic was acquired during the late afternoon (near 5pm LST, note the long shadows) on Sol 2 as part of the predeploy "insurance panorama" and shows the newly deployed rover sitting on the Martian surface. This color image was generated from images acquired at 530,600, and 750 nm. The insurance panorama was designed as "insurance" against camera failure upon deployment. Had the camera failed, the losslessly-compressed, multispectral insurance panorama would have been the main source of image data from the IMP. However, the camera deployment was successful, leaving the insurance panorama to be downlinked to Earth several weeks later. Ironically enough, the insurance panorama contains some of the best quality image data because of the lossless data compression and relatively dust-free state of the camera and associated lander/rover hardware on Sol 2. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal investigator. *Image Credit*: NASA |
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360 Degree Panorama Mars Pat
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| Title |
360 Degree Panorama Mars Pathfinder Landing Site |
| Full Description |
This is the first contiguous, uniform 360-degree color panorama taken by the Imager for Mars Pathfinder (IMP) over the course of sols 8, 9, and 10 (Martian days). Different regions were imaged at different times over the three Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama. At left is a lander petal and a metallic mast which is a portion of the low-gain antenna. On the horizon the double "Twin Peaks" are visible, about 1-2 kilometers away. The rock "Couch" is the dark, curved rock at right of Twin Peaks. Another lander petal is at left-center, showing the fully deployed forward ramp at far left, and rear ramp at right, which rover Sojourner used to descend to the surface of Mars on July 5. Immediately to the left of the rear ramp is the rock Barnacle Bill, which scientists found to be andesitic, possibly indicating that it is a volcanic rock (a true andesite) or a physical mixture of particles. Just beyond Barnacle Bill, rover tracks lead to Sojourner, shown using its Alpha Proton X-Ray Spectrometer (APXS) instrument to study the large rock Yogi. Yogi, low in quartz content, appears to be more primitive than Barnacle Bill, and appeared more like the common basalts found on Earth. The tracks and circular pattern in the soil leading up to Yogi were part of Sojourner's soil mechanics experiments, in which varying amounts of pressure were applied to the wheels in order to determine physical properties of the soil. During its traverse to Yogi the rover stirred the soil and exposed material from several centimeters in depth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer, the wheels dug particularly deeply and exposed white material. Spectra of this white material show it is virtually identical to the rock Scooby Doo, and such white material may underlie much of the site. Deflated airbags are visible at the perimeter of all three lander petals. The IMP is a stereo imaging system with color capability provided by 24 selectable filters, twelve filters per "eye." Its red, green, and blue filters were used to take this image. The IMP, in its fully deployed configuration, stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. |
| Date |
07/18/1997 |
| NASA Center |
Jet Propulsion Laboratory |
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Mars Climate Orbiter
| Title |
Mars Climate Orbiter |
| Full Description |
The Mars Surveyor '98 Climate Orbiter is shown here during acoustic tests that simulate launch conditions. The orbiter was to conduct a two year primary mission to profile the Martian atmosphere and map the surface. To carry out these scientific objectives, the spacecraft carried a rebuilt version of the pressure modulated infrared radiometer, lost with the Mars Observer spacecraft, and a miniaturized dual camera system the size of a pair of binoculars, provided by Malin Space Science Systems, Inc., San Diego, California. During its primary mission, the orbiter was to monitor Mars atmosphere and surface globally on a daily basis for one Martian year (two Earth years), observing the appearance and movement of atmospheric dust and water vapor, as well as characterizing seasonal changes of the planet's surface. Imaging of the surface morphology would also provide important clues about the planet's climate in its early history. The mission was part of NASA's Mars Surveyor program, a sustained program of robotic exploration of the red planet, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. Lockheed Martin Astronautics was NASA's industrial partner in the mission. Unfortunately, Mars Climate Orbiter burned up in the Martian atmosphere on September 23, 1999, due to a metric conversion error that caused the spacecraft to be off course. |
| Date |
05/27/1998 |
| NASA Center |
Jet Propulsion Laboratory |
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Rolling Stones Make New Boul
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Rolling Stones Make New Boulder Tracks |
| Description |
When a boulder rolls down a dusty slope, it can leave behind a trail of depressions. Usually known as boulder tracks, these features have been documented and studied on Earth, the Moon, and Mars. Geologists studying the Moon and Mars can use these tracks to learn about the physical properties of the fine-grained debris encountered by the boulder as it rolled down the slope. Because of the high-resolution capability (0.5 to 12 meters, 1.6 to 39 feet, per pixel) of the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, dozens of boulder track sites have been identified on the red planet. A Mars Orbiter Camera image of one set of boulder tracks in a south mid-latitude crater (located near 35.8 degrees south latitude, 158.4 degrees west longitude) was obtained on Nov. 14, 2003, (left). A second image of the same site, from Dec. 4, 2004, (right) shows that more than a dozen new boulder tracks formed on the crater wall during the intervening time. Mars is an active planet, with geologic changes occurring -- at some scale -- every day. In this case, some time between mid November 2003 and early December 2004, a suite of boulders became dislodged from the crater wall, then rolled and perhaps bounced their way to the crater floor. Wider context for the site can be seen in a mosaic of Mars Orbiter Camera wide-angle images acquired in May 1999 (insert MOC2-1213a). The white box indicates the location of the later, higher-resolution views. Why the new boulders slid down the slope is unknown. This is the product of a mass movement (landsliding) process. That is, gravity is the main culprit. Whether the boulder motion was triggered by something -- a seismic event ("Marsquake") or strong winds -- is not known. Also unknown is whether all of the new boulder tracks formed at the same time, in response to a single event, or rolled downhill one at a time over the nearly 13-month period. 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 |
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Scarp at Head of Chasma Bore
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| 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 |
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Eberswalde Delta in High Res
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| title |
Eberswalde Delta in High Resolution |
| Description |
Scientifically, perhaps the most important result from use of the Mars Orbiter Camera on NASA's Mars Global Surveyor during that spacecraft's extended mission has been the discovery and documentation of a fossil delta. The feature is located in a crater northeast of Holden Crater, near 24.0 degrees south latitude, 33.7 degrees west longitude. Since the announcement of the discovery of the delta in November 2003, the International Astronomical Union has provided a provisional name (pending final approval) for the crater in which the landforms occur. The crater has been named Eberswalde, for a town in Germany. This image offers a higher-resolution view of a portion of the fossil delta than any seen earlier. North is up. At the bottom of the frame, the image includes the north end of a looping, inverted, meandering channel. The image covers an area of about 3 by 3 kilometers (1.9 x 1.9 miles). It was produced using a technique called "compensated pitch and roll targeted observation," in which the rotation rate of the spacecraft is adjusted to match the ground speed under the camera. At full resolution, this map-projected image is at 50 centimeters (20 inches) per pixel. Additional images from Mars Orbiter Camera provide some context and show a nearby portion of the fossil delta's inverted channels at a spatial scale of 1.5 meters (about 5 feet) per pixel. The relative positions of these three images are indicated in a mosaic image of the entire delta, for which the unmarked version was released in November 2003. The first Mars Orbiter Camera narrow angle images of some of the landforms in the delta were acquired in 2000, during the Mars Global Surveyor primary mission, but those pictures did not show very well the unambiguous inverted channel forms. Not until the second Earth year of the orbiter's extended mission were the deltaic features recognized in Mars Orbiter Camera images obtained in March and June of 2002. Following the initial observations in 2002, the Mars Orbiter Camera team began a systematic effort to map the entire Eberswalde Crater delta. Most of this imaging required slewing the whole spacecraft in a technique called "roll only targeted observation" so that it pointed the camera toward the feature. In this way, the camera team was able to build up a mosaic of the delta much more quickly than would have been the case if the team had simply relied upon chance crossing of the delta by the orbiter's usual ground track. This technique was not employed during Mars Global Surveyor's primary mission, except in the search for Mars Polar Lander, but became a routine part of the tool kit during the extended mission. Even with the "roll only targeted observation" technique, it took more than one Earth year to build up a complete mosaic of images of the delta. In the meantime, the first data showing the deltaic landforms were archived and released to the public and scientific community, long before the Mars Orbiter Camera team's, analysis and mosaic were complete. Some scientists began independent analyses of the landform at that time. The initial analysis and announcement of the feature was finally published in November 2003. The Eberswalde delta provides the first clear, "smoking gun" evidence that some valleys on Mars experienced persistent flow of a liquid with the physical properties of water over an extended period of time, as do rivers on Earth. In addition, because the delta today is lithified -- that is, hardened to form rock -- it provided the first unambiguous evidence that some martian sedimentary rocks were deposited in a liquid (presumably, water) environment. The presence of meandering channels, a cut-off meander, and crisscrossing channels at different elevations (one above the other), provided the clear geologic evidence for these interpretations. After the sediments were deposited to form the delta, the material was further buried by other materials -- probably sediments -- that are no longer present. The entire package of buried material became cemented and hardened to form rock. Later, erosive processes such as wind stripped away the overlying rock, re-exposing the delta. Now preserved essentially as a fossil, the former floors of channels in the delta became inverted, to form ridges, by erosion. Channels can be inverted by erosion on both Earth and Mars. Usually this happens when the channel floor, or the material filling the channel, is harder to erode than the surrounding material into which the channel was cut. In some cases, the channels on Earth and Mars have been filled by lava to make them more resistant to erosion. In the case of Eberswalde, there are no lava flows, instead, the channel floors may have been rendered resistant to erosion either by being better-cemented than the surrounding material, or composed of coarser-grained sediment (such as sand and gravel as opposed to silt), or both. 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 |
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Recently-Formed Impact Crate
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| title |
Recently-Formed Impact Crater |
| Description |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a number, of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (insert MOC2-1214b), and in even wider context in a regional mosaic of Viking images (insert MOC2-1214c). 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/USGS |
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Four Mars Years of South Pol
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| title |
Four Mars Years of South Polar Changes |
| Description |
One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission. The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers. It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed. The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer. The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year (and, of course, most of that retreat takes place during the summer). In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per martian year. Of the two volatile materials one is likely to find in a frozen state on Mars -- water and carbon dioxide -- it is carbon dioxide that is volatile enough to permit scarp retreat rates like those observed by the Mars Orbiter Camera. Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. Since 2001, two additional Mars years have elapsed. A scientific benefit of having a long extended mission for Mars Global Surveyor has been the opportunity to document how the polar cap is changing each year. Four images are shown here, plus an animation at left presenting the four frames in sequence. The location is near 86.3 degrees south latitude, 49.4 degrees west longitude, and the images show the same portion of the south polar residual, cap as it appeared in 1999, 2001, 2003, and 2005. Comparing the images or viewing the animation makes it evident that the landscape of the south polar cap has been changing rapidly over the past four martian years. Each year that Mars Global Surveyor has been in orbit, the landforms of the south polar residual cap have gotten smaller, and the carbon dioxide removed from the cap has not been re-deposited. The implication is that Mars presently has a warm (and possibly warming) climate, with new carbon dioxide going into the atmosphere every year. The other implication is that, at some time in the not-too-distant past, the planet had a colder climate, so that the layers of carbon dioxide could be deposited in the first place. If one takes the rate of scarp retreat and projects it backwards to fill in all of the pits and troughs with the carbon dioxide that has been removed from them, one finds that the colder climate might only have occurred a few centuries to a few tens of thousands of years ago. This kind of time scale is not unlike that of the climate changes that have been recorded on Earth, including the Ice Ages and the smaller fluctuations that have occurred since the last Ice Age (e.g., the "Little Ice Age" of the mid-14th through mid-19th centuries). After the discovery that the pits were enlarging and that we were not seeing carbon-dioxide deposition, it was suggested that interannual variations might be large enough to permit such deposition on a short timescale. However, two Mars years of additional observations show no large magnitude annual differences. Variations that would permit carbon dioxide deposition may require decades. And to see such variations may require many more Mars years of observations by orbiting spacecraft. 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 |
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Repeated Clouds over Arsia M
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| title |
Repeated Clouds over Arsia Mons |
| Description |
Three wide angle views taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor at intervals approximately one Mars year apart show similar spiral dust clouds over a volcano named Arsia Mons. The upper-left image was taken on June 19, 2001, the first day of southern winter on Mars. The upper-right image was taken on April 24, 2003, in late southern autumn on Mars. The lower image was taken on Feb. 25, 2005, slightly earlier in late southern autumn on Mars. Some parts of Mars experience weather phenomena that repeat each year at about the same time. In some regions, the repeated event may be a dust storm that appears every year, like clockwork, in such a way that we can only wish the weather were so predictable on Earth. One of the repeated weather phenomena occurs each year near the start of southern winter over Arsia Mons, which is located near 9 degrees south latitude, 121 degrees west longitude. Just before southern winter begins, sunlight warms the air on the slopes of the volcano. This air rises, bringing small amounts of dust with it. Eventually, the rising air converges over the volcano's caldera, the large, circular depression at its summit. The fine sediment blown up from the volcano's slopes coalesces into a spiraling cloud of dust that is thick enough to actually observe from orbit. The spiral dust cloud over Arsia Mons repeats each year, but observations and computer calculations indicate it can only form during a short period of time each year. Similar spiral clouds have not been seen over the other large Tharsis volcanoes, but other types of clouds have been seen. The spiral dust cloud over Arsia Mons can tower 15 to 30 kilometers (9 to 19 miles) above the volcano. The white and bluish areas in the images are thin clouds of water ice. In the 2005 case, more water ice was present than in the previous years at the time the pictures were obtained. For scale, the caldera of Arsia Mons is about 110 kilometers (68 miles) across, and the summit of the volcano stands about 10 kilometers (6 miles) above its surrounding plains. 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 |
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New Gullies on Martian Sand
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| 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 |
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Close-up of Moe - Left Eye
| title |
Close-up of Moe - Left Eye |
| Description |
A close-up view of the rock 'Moe' in the Rock Garden at the Pathfinder landing site. Moe is a meter-size boulder that, as seen from Sojourner, has a relatively smooth yet pitted texture upon close examination. Such a texture is seen on Earth on rocks that have been abraded by wind in a process that is analogous to sand blasting. This view of Moe shows two faces on the rock, one (left side of the rock) facing north-northeast and the other (right side) facing east. These two faces are thought to have been pitted and fluted by strong, 'sand'- carrying winds from the northeast. This image and PIA01565 [ http://photojournal.jpl.nasa.gov/catalog/PIA01565 ] (right eye) make up a stereo pair. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). |
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Improved MPF 360-degree Colo
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| title |
Improved MPF 360-degree Color Panorama |
| Description |
Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator., This is a more recent 'geometrically improved, color enhanced' version of the 360-degree 'Gallery Pan', the first contiguous, uniform panorama taken by the Imager for Mars (IMP) over the course of Sols 8, 9, and 10. Different regions were imaged at different times over the three Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama. In this version of the panorama, much of the discontinuity that was due to parallax has been corrected, particularly along the lower tiers of the mosaic containing the Lander features. Distortion due to a 2.5 degree tilt in the IMP camera mast has been removed. The IMP is a stereo imaging system that, in its fully deployed configuration, stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters. The IMP has color capability provided by 24 selectable filters -- twelve filters per 'eye'. Its red, green, and blue filters were used to take this panorama. The three color images were first digitally balanced according to the transmittance capabilities of a specific high-definition TV device at JPL, and then enhanced via changes to saturation and intensity while retaining the hue. A threshold was applied to avoid changes to the sky. An MTF filter was applied to sharpen feature edges. At left is a Lander petal and a metallic mast which is a portion of the low-gain antenna. On the horizon the double 'Twin Peaks' are visible, about 1-2 kilometers away. The rock 'Couch' is the dark, curved rock at right of Twin Peaks. Another Lander petal is at left-center, showing the fully deployed forward ramp at far left, and rear ramp at right, which rover Sojourner used to descend to the surface of Mars on July 5. Immediately to the left of the rear ramp is the rock 'Barnacle Bill', which scientists found be andesitic, possibly indicating that it is a volcanic rock (a true andesite) or a physical mixture of particles. Just beyond Barnacle Bill, rover tracks lead to Sojourner, shown using its Alpha Proton X-Ray Spectrometer (APXS) instrument to study the large rock 'Yogi'. Yogi, low in quartz content, appears to be more primitive than Barnacle Bill, and appears more like the common basalts found on Earth. The tracks and circular pattern in the soil leading up to Yogi were part of Sojourner's soil mechanics experiments, in which varying amounts of pressure were applied to the wheels in order to determine physical properties of the soil. During its traverse to Yogi the rover stirred the soil and exposed material from several centimeters in depth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer, the wheels dug particularly deeply and exposed white material. Spectra of this white material show it is virtually identical to the rock 'Scooby Doo', and such white material may underlie much of the site. Deflated airbags are visible at the perimeter of all three Lander petals. Mars Pathfinder is the second in NASA's |
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North Polar Layered Deposits
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North Polar Layered Deposits in Summer |
| Description |
The High Resolution Imaging Science Experiment (HiRISE) on NASA's Mars Reconnaissance Orbiter acquired this image during its first day of test imaging from the spacecraft's low-altitude mapping orbit, Sept. 29, 2006. This image of Mars' north polar layered deposits was taken during the summer season (solar longitude of 113.6 degrees), when carbon dioxide frost had evaporated from the surface. The bright spots seen here are most likely patches of water frost, but the location of the frost patches does not appear to controlled by topography. Layers are visible at the bottom of the image, mostly due to difference in slope between them. The variations in slope are probably caused by differences in the physical properties of the layers. Thinner layers that have previously been observed in these deposits are visible, and may represent annual deposition of water ice and dust that is thought to form the polar layered deposits. These deposits are thought to record global climate variations on Mars, similar to ice ages on Earth. HiRISE images such as this should allow Mars' climate record to be inferred and compared with climate changes on Earth. Image TRA_000825_2665 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on September 29, 2006. Shown here is the full image, centered at 86.5 degree latitude, 172.0 degrees east longitude. The image is oriented such that north is to the top. The range to the target site was 298.9 kilometers (186.8 miles). At this distance the image scale is 59.8 centimeters (23.5 inches) per pixel (with two-by-two binning} so objects about 1.79 meters (70 inches) across are resolved. In total the original image was 12.2 kilometers 7.58 mile, 10024 pixels) wide and 6.1 kilometers (3.79 miles, 5000 pixels) long. The image was taken at a local Mars time of 3:30 PM and the scene is illuminated from the southwest with a solar incidence angle of 63.5 degrees, thus the sun was about 26.5 degrees above the horizon. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace Corporation and is operated by the University of Arizona. Credit: NASA/JPL/UA |
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| Description |
MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov [ http://www.jpl.nasa.gov ] PHOTO CAPTION PIA-00558 [ http://photojournal.jpl.nasa.gov/catalog/PIA00558 ] Earth from Mars Odyssey April 23, 2001 The 2001 Mars Odyssey's thermal emission imaging system acquired these images of the Earth using its visible and infrared cameras as the spacecraft left the Earth. The visible light image shows the thin crescent viewed from Odyssey's perspective. The infrared image was acquired at exactly the same time, but shows the entire Earth using the infrared's "night-vision" capability. In visible light, the instrument sees only reflected sunlight and therefore sees nothing on the night side of the planet. In infrared light the camera observes the light emitted by all regions of the Earth. The coldest ground temperatures seen correspond to the nighttime regions of Antarctica, the warmest temperatures occur in Australia. The low temperature in Antarctica is minus 50 degrees Celsius (minus 58 degrees Fahrenheit), the high temperature at night in Australia 9 degrees Celsius (48.2 degrees Fahrenheit). These temperatures agree remarkably well with observed temperatures of minus 63 degrees Celsius at Vostok Station in Antarctica, and 10 degrees Celsius in Australia. The images were taken at a distance of 3,563,735 kilometers (more than 2 million miles) on April 19, 2001 as the Odyssey spacecraft left Earth. Mars Odyssey carries three scientific instruments designed to tell us what the Martian surface is made of and about its radiation environment: a thermal-emission imaging system, a gamma ray spectrometer and a Martian radiation environment experiment. Odyssey will arrive at Mars on October 24, when it will fire its main engine and be captured into Mars' orbit. The Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. Principal investigators at Arizona State University in Tempe, the University of Arizona in Tuscon, and NASA's Johnson Space Center, Houston, Texas, will operate the science instruments. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations will be conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. The thermal emission imaging system was built by Raytheon Santa Barbara Remote Sensing, Santa Barbara, Calif. and is operated by Arizona State University. ##### Image credit: NASA/Jet Propulsion Laboratory/Arizona State University |
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First HiRISE image of Mars
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First HiRISE image of Mars |
| Description |
. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. Credit: NASA/JPL/University of Arizona, The first image of Mars by the High Resolution Imaging Science Experiment (HiRISE) on NASA's Mars Reconnaissance Orbiter shows a story of geologic change in the eastern Bosporos Planum region. Old stream valleys cut into the flanks of a gently sloping mountain range in the center of the image. Layers of smooth-textured deposits have mantled the stream valleys and many impact craters. Wind and sublimation of water or carbon dioxide ice have partially eroded patches of the smooth-textured deposits, leaving behind areas of layered and hummocky terrain. A prominent ridge that extends from the top to the bottom of the image dominates the scene. This ridge formed above a thrust fault, a type of fault that occurs when the surface of a planet is compressed. On planetary surfaces, such fault-related ridges are termed "wrinkle ridges." They are commonly observed on Mars, as well as on Earth's moon and on Venus and Mercury. The wrinkle ridge imaged here is named Ogygis Rupes. This wrinkle ridge has deformed several valleys and impact craters. Throughout the scene, geologically young sand dunes are present within stream valleys and some impact craters. The area is also sprinkled with many small young impact craters, which are distinguished by sharp crater rims and bright or dark halos of ejected material. This image demonstrates how a single HiRISE image can capture a multitude of geologic processes. Image AEB_000001_0000_Red was taken by HiRISE on March 24, 2006. The image is centered at 33.65 degrees south latitude, 305.07 degrees east longitude. It is oriented such that north is 7 degrees to the left of up. The range to the target was 2,493 kilometers (1,549 miles). At this distance the image scale is 2.49 meters (8.17 feet) per pixel, so objects as small as 7.5 meters (24.6 feet) are resolved. In total this image is 49.92 kilometers (31.02 miles) or 20,081 pixels wide and 23.66 kilometers (14.70 miles) or 9,523 pixels long. The image was taken at a local Mars time of 07:33 and the scene is illuminated from the upper right with a solar incidence angle of 78 degrees, thus the sun was 12 degrees above the horizon. At an Ls of 29 degrees (with Ls an indicator of Mars' position in its orbit around the sun), the season on Mars is southern autumn. Images from the High Resolution Imaging Science Experiment and additional information about the Mars Reconnaissance Orbiter are available online at: http://www.nasa.gov/mro [ http://www.nasa.gov/mro ] or http://HiRISE.lpl.arizona.edu [ http://HiRISE.lpl.arizona.edu ]. For information about NASA and agency programs on the Web, visit: http://www.nasa.gov [ http://www.nasa.gov ] |
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| Description |
MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov [ http://www.jpl.nasa.gov ] PHOTO CAPTION PIA-00559 [ http://photojournal.jpl.nasa.gov/catalog/PIA00559 ] Earth & Moon from Mars Odyssey April 23, 2001 2001 Mars Odyssey's thermal emission imaging system took this portrait of the Earth and its companion Moon, using the infrared camera, one of two cameras in the instrument. It was taken at distance of 3,563,735 kilometers (more than 2 million miles) on April 19, 2001 as the 2001 Mars Odyssey spacecraft left the Earth. From this distance and perspective the camera was able to acquire an image that directly shows the true distance from the Earth to the Moon. The Earth's diameter is about 12,750 kilometers, and the distance from the Earth to the Moon is about 385,000 kilometers, corresponding to 30 Earth diameters. The dark region seen on Earth in the infrared temperature image is the cold south pole, with a temperature of minus 50 degrees Celsius (minus 58 degrees Fahrenheit). The small bright region above it is warm Australia. This image was acquired using the 9.1 micron infrared filter, one of nine filters that the instrument will use to map the mineral composition and temperature of the Martian surface. From this great distance, each picture element (pixel) in the image corresponds to a region 900 by 900 kilometers (about 560 by 560 miles). Once Odyssey reaches Mars orbit each infrared pixel will cover a region only 100 by 100 meters on the surface (about 330 by 330 feet), about the size of a major league baseball field. Mars Odyssey carries three scientific instruments designed to tell us what the Martian surface is made of and about its radiation environment: a thermal-emission imaging system, a gamma ray spectrometer and a Martian radiation environment experiment. Odyssey will arrive at Mars on October 24, when it will fire its main engine and be captured into Mars' orbit. The Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. Principal investigators at Arizona State University in Tempe, the University of Arizona in Tuscon, and NASA's Johnson Space Center, Houston, Texas, will operate the science instruments. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations will be conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. The thermal emission imaging system was built by Raytheon Santa Barbara Remote Sensing, Santa Barbara, Calif. and is operated by Arizona State University. ##### Image credit: NASA/Jet Propulsion Laboratory/Arizona State University |
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Map of Martian Silicon at Mi
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| title |
Map of Martian Silicon at Mid-Latitudes |
| Description |
This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element silicon. Silicon is one of the most abundant elements on the surface of both Mars and Earth (second only to oxygen). The most extensive region of highest silicon content, shown in red, is located in the high latitudes north of Tharsis (centered near 45 degrees latitude, -120 degrees longitude). The area of lowest silicon content, shown in blue, lies just to the east of the Hellas Basin (-45 degrees latitude, 90 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the 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. Credit: NASA/JPL/University of Arizona |
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Map of Martian Iron at Mid-L
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| title |
Map of Martian Iron at Mid-Latitudes |
| Description |
This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element iron. Iron, having the chemical symbol Fe, is among of the most abundant elements on the surface of both Mars and Earth. It is responsible for the red color on the surface of Mars. Regions of highest iron content, shown in red, are concentrated in the area spanning from Utopia Planitia to Amazonis Planitia (right and left sides of the map) and within Acidalia Planitia (just left of center). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the 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. Credit: NASA/JPL/University of Arizona |
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Radiation environment at Mar
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| title |
Radiation environment at Mars and Earth December 8, 2003 |
| Description |
This graphic shows the radiation dose equivalent as measured by Odyssey's martian radiation environment experiment at Mars and by instruments aboard the Earth-orbiting International Space Station (ISS), for the 18-month period from April 2002 through October 2003. The accumulated total in Mars orbit is just over two times larger than that aboard the Space Station. The bars where the Mars instrument's measurements are well above the average (as shown by the orange line) are months when there was significant solar activity, which increases the dose equivalent. Dose equivalent is expressed in units of milliSieverts per day. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington. The radiation experiment was provided by the Johnson Space Center, Houston, Texas. Lockheed Martin Space Systems, Denver, Colo., is the prime contractor for the 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. Credit: NASA/JPL/JSC ### |
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Mars Odyssey Seen by Mars Gl
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| 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 |
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3-D Perspective of Mt. Etna:
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nasa, nasaimageofthedaygalle
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Italy's Mount Etna is the fo
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etna_TAS2002209
| mediatype |
IMAGE |
| mediatype |
image |
| date |
2000-02-11 |
| creator |
NASA -- Image courtesy ASTER and SRTM Teams, NASA's Jet Propulsion Laboratory |
| identifier |
etna_TAS2002209 |
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Waning Iapetus
PIA06145
Saturn
Imaging Science Subsystem -
…
| Title |
Waning Iapetus |
| Original Caption Released with Image |
These spectacular Cassini images of Saturn's moon Iapetus show an enticing world of contrasts. These are the sharpest views of Iapetus from Cassini so far, and they represent better resolution than the best images of this moon achieved by NASA's Voyager spacecraft. Images obtained using ultraviolet (centered at 338 nanometers), green (568 nanometers) and infrared (930 nanometers) filters were combined to produce the enhanced color views at left and center, the image at the right was obtained in visible white light. The images on the bottom row are identical to those on top, with the addition of an overlying coordinate grid. These views show parts of the moon's anti-Saturn side--the side that faces away from the ringed planet--which will not be imaged again by Cassini until Sept., 2007. In the central view, part of the moon's eastern edge was not imaged and appears to be cut off. With a diameter of 1,436 kilometers (892 miles), Iapetus is Saturn's third largest moon. It is famous for the dramatic contrasts in brightness on its surface--the leading hemisphere is as dark as a freshly-tarred street, and the trailing hemisphere and poles almost as bright as snow. Many impact craters can be seen in the bright terrain and in the transition zone between bright and dark, and for the first time in parts of the dark terrain. Also visible is a line of mountains that appear as a string of bright dots in the two color images at left, and on the eastern limb in the image at right. These mountains were originally detected in Voyager images, and might compete in height with the tallest mountains on Earth, Jupiter's moon Io and possibly even Mars. Further observations will be required to precisely determine their heights. Interestingly, the line of peaks is aligned remarkably close to the equator of Iapetus. The large circular feature rotating into view in the southern hemisphere is probably an impact structure with a diameter of more than 400 kilometers (250 miles), and was first seen in low-resolution Cassini images just two months earlier. Theses images were taken with the Cassini spacecraft narrow angle camera between Oct, 15 and 20, 2004, at distances of 1.2, 1.1 and 1.3 million kilometers (746,000, 684,000 and 808,000 miles) from Iapetus, respectively. The Sun-Iapetus-spacecraft, or phase, angle changes from 88 to 144 degrees across the three images. The image scale is approximately 7 kilometers (4.5 miles) per pixel. 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 Cassini-Huygens mission for NASA's Office of Space Science, 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 [ http://saturn.jpl.nasa.gov/ ] and the Cassini imaging team home page, http://ciclops.org [ http://ciclops.org/ ]. |
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Giant Landslide on Iapetus
PIA06171
Saturn
Imaging Science Subsystem -
…
| Title |
Giant Landslide on Iapetus |
| Original Caption Released with Image |
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 [ http://saturn.jpl.nasa.gov ]. For images visit the Cassini imaging team home page http://ciclops.org [ http://ciclops.org ]. |
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Eyes on Iapetus!
PIA08371
Saturn
Imaging Science Subsystem
| Title |
Eyes on Iapetus! |
| Original Caption Released with Image |
This map of the surface of Iapetus, generated from images taken by NASA's Cassini and Voyager spacecraft, illustrates the imaging coverage planned for Cassini's very close flyby of the two-toned moon on Sept. 10, 2007. This flyby will be Cassini's only close approach to Iapetus (1,468 kilometers, or 912 miles across) during the entire planned mission. At closest approach, Cassini will be 1,640 kilometers (1,020 miles) above the surface of Iapetus. The spacecraft will pass the moon at a speed of about 2.4 kilometers (1.5 miles) per second--a relatively leisurely pace that will allow plenty of time for the scientific instruments on board to collect massive amounts of data. Cassini's previous encounter with Iapetus, on Dec. 31, 2004, focused on the mysterious territory in Cassini Regio, the region blanketed by dark material that covers most of the moon's leading hemisphere. The upcoming encounter will be primarily concerned with terrain farther west, in the important transition region between Cassini Regio and the bright trailing hemisphere. Scientists hope to learn a great deal more about the composition of the materials that compose the surface of Iapetus during this encounter. Another area of focus is the large equatorial ridge that overlies the moon's equator (see PIA06166 [ http://photojournal.jpl.nasa.gov/catalog/PIA06166 ]). The ridge reaches 20 kilometers (12 miles) high in some places and extends over 1,300 kilometers (808 miles) in length. No other moon in the solar system has a geological feature like this striking ridge. The tallest mountains on the ridge rival Olympus Mons on Mars, which is approximately three times the height of Mt. Everest. Such giant mountains are a surprising feature for such a small body as Iapetus, which is nearly five times smaller than Mars and nearly nine times smaller than Earth. Colored lines on the map enclose regions that will be covered at different imaging scales as Cassini encounters Iapetus. The highest expected resolution of Cassini images from this flyby is about 20 meters (65 feet) per pixel--significantly higher than the 2004 encounter. 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 operations center is based at the Space Science Institute in Boulder, Colo. For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm [ http://saturn.jpl.nasa.gov ]. The Cassini imaging team homepage is at http://ciclops.org [ http://ciclops.org ]. |
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Martian soil color variation
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PIA00757
Sol (our sun)
Imager for Mars Pathfinder
| Title |
Martian soil color variations |
| Original Caption Released with Image |
Rocks and soils on the surface are thought to be composed of minerals similar to those found on Earth's surface. One of the most important tools for recognizing these minerals is the spectrum of sunlight reflected by them. At the visible and near-infrared light wavelengths measured by the Imager for Mars Pathfinder (IMP), the most important coloring materials in the Martian surface are iron minerals. There are two broad classes of iron minerals. Minerals which occur in igneous rocks (such as pyroxene) have a relatively flat spectrum and they reflect only a small amount of light, they are said to have a low reflectance. Ferric iron minerals, which occur as weathering products, reflect longer-wavelength light and absorb short-wavelength light, hence their very red color. The relative brightnesses of Martian surface materials in IMP's different wavelength filter is a powerful tool for recognizing the iron minerals present. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech). |
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New 360 degree color gallery
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PIA00752
Sol (our sun)
Imager for Mars Pathfinder
| Title |
New 360 degree color gallery panorama |
| Original Caption Released with Image |
This is the first contiguous, uniform 360-degree color panorama taken by the Imager for Mars Pathfinder (IMP) over the course of sols 8, 9, and 10. Different regions were imaged at different times over the three Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama. At left is a lander petal and a metallic mast which is a portion of the low-gain antenna. On the horizon the double "Twin Peaks" are visible, about 1-2 kilometers away. The rock "Couch" is the dark, curved rock at right of Twin Peaks. Another lander petal is at left-center, showing the fully deployed forward ramp at far left, and rear ramp at right, which rover Sojourner used to descend to the surface of Mars on July 5. Immediately to the left of the rear ramp is the rock Barnacle Bill, which scientists found to be andesitic, possibly indicating that it is a volcanic rock (a true andesite) or a physical mixture of particles. Just beyond Barnacle Bill, rover tracks lead to Sojourner, shown using its Alpha Proton X-Ray Spectrometer (APXS) instrument to study the large rock Yogi. Yogi, low in quartz content, appears to be more primitive than Barnacle Bill, and appeared more like the common basalts found on Earth. The tracks and circular pattern in the soil leading up to Yogi were part of Sojourner's soil mechanics experiments, in which varying amounts of pressure were applied to the wheels in order to determine physical properties of the soil. During its traverse to Yogi the rover stirred the soil and exposed material from several centimeters in depth. During one of the turns to deploy Sojourner's Alpha Proton X-Ray Spectrometer, the wheels dug particularly deeply and exposed white material. Spectra of this white material show it is virtually identical to the rock Scooby Doo, and such white material may underlie much of the site. Deflated airbags are visible at the perimeter of all three lander petals. The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per "eye." Its red, green, and blue filters were used to take this image. The IMP, in its fully deployed configuration, stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. |
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Perspective View, Mt. Etna,
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PIA03370
Sol (our sun)
ASTER, C-Band Interferometri
…
| Title |
Perspective View, Mt. Etna, Italy & the Aeolian Islands |
| Original Caption Released with Image |
Italy's Mount Etna and the Aeolian Islands are the focus of this perspective view made from an Advanced Spaceborne Thermal and Emission Radiometer (ASTER) image from NASA's Terra spacecraft overlaid on Shuttle Radar Topography Mission (SRTM) topography. The image is looking south with the islands of Lipari and Vulcano in the foreground and Etna with its dark lava flows on the skyline. Vulcano also hosts an active volcano, the cone of which is prominent. In late October 2002, Etna erupted again, sending lava flows down the north and south sides of the volcano. The north flows are near the center of this view, but the ASTER image is from before the eruption. In addition to the terrestrial applications of these data for understanding active volcanoes and hazards associated with them such as lava flows and explosive eruptions, geologists studying Mars find these data useful as an analog to martian landforms and geologic processes. In late September 2002, a field conference with the theme of Terrestrial Analogs to Mars focused on Mount Etna allowing Mars geologists to see in person the types of features they can only sample remotely. Elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Size: Varies across scene Location: 38.25 degrees North latitude, 15 degrees East longitude Orientation: Looking south Image Data: ASTER bands 2, 3, 1 as red, green, blue, respectively. Original Data Resolution: SRTM 1 arc-second (30 meters or 98 feet) Date Acquired: February 2000 (SRTM), July 29, 2001 (ASTER) |
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Perspective View, Mt. Etna,
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PIA03371
Sol (our sun)
ASTER, C-Band Interferometri
…
| Title |
Perspective View, Mt. Etna, Italy |
| Original Caption Released with Image |
Italy's Mount Etna is the focus of this perspective view made from an Advanced Spaceborne Thermal and Emission Radiometer (ASTER) image from NASA's Terra spacecraft overlaid on Shuttle Radar Topography Mission (SRTM) topography. The image is looking south with dark lava flows from the 1600's (center) to 1981 (long flow at lower right) visible in the foreground and the summit of Etna above. The city of Catania is barely visible behind Etna on the bay at the upper left. In late October 2002, Etna erupted again, sending lava flows down the north and south sides of the volcano. The north flows are near the center of this view, but the ASTER image is from before the eruption. In addition to the terrestrial applications of these data for understanding active volcanoes and hazards associated with them such as lava flows and explosive eruptions, geologists studying Mars find these data useful as an analog to martian landforms and geologic processes. In late September 2002, a field conference with the theme of Terrestrial Analogs to Mars focused on Mount Etna, allowing Mars geologists to see in person the types of features they can only sample remotely. Elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Size: Varies across scene Location: 38 degrees North latitude, 15.5 degrees East longitude Orientation: Looking south Image Data: ASTER bands 2, 3, 1 as red, green, blue, respectively. Original Data Resolution: SRTM 1 arc-second (30 meters or 98 feet) Date Acquired: February 2000 (SRTM), July 29, 2001 (ASTER) |
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Odyssey/Marie
PIA03745
Sol (our sun)
Mars Radiation Experiment
| Title |
Odyssey/Marie |
| Original Caption Released with Image |
Data from Odyssey's Martian radiation environment experiment show that the radiation dose equivalent at Mars is two to three times greater than that aboard the International Space Station. The differences are primarily due to the magnetic field surrounding the Earth, which provides considerable shielding to astronauts in orbit. Mars lacks a strong magnetic field and is therefore more exposed to the harshest elements of space radiation. JPL, a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey mission for NASA's Office of Space Science in Washington, D.C. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center, Houston, operate the science instruments. Additional science partners are located at the Russian Aviation and Space Agency and at Los Alamos National Laboratories, New Mexico. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL. |
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Close-up of Moe - Left Eye
PIA01564
Sol (our sun)
Rover Cameras
| Title |
Close-up of Moe - Left Eye |
| Original Caption Released with Image |
A close-up view of the rock "Moe" in the Rock Garden at the Pathfinder landing site. Moe is a meter-size boulder that, as seen from Sojourner, has a relatively smooth yet pitted texture upon close examination. Such a texture is seen on Earth on rocks that have been abraded by wind in a process that is analogous to sand blasting. This view of Moe shows two faces on the rock, one (left side of the rock) facing north-northeast and the other (right side) facing east. These two faces are thought to have been pitted and fluted by strong, "sand"- carrying winds from the northeast. This image and PIA01565 [ http://photojournal.jpl.nasa.gov/catalog/PIA01565 ](right eye) make up a stereo pair. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). |
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Close-up of Moe - Right Eye
PIA01565
Sol (our sun)
Rover Cameras
| Title |
Close-up of Moe - Right Eye |
| Original Caption Released with Image |
A close-up view of the rock "Moe" in the Rock Garden at the Pathfinder landing site. Moe is a meter-size boulder that, as seen from Sojourner, has a relatively smooth yet pitted texture upon close examination. Such a texture is seen on Earth on rocks that have been abraded by wind in a process that is analogous to sand blasting. This view of Moe shows two faces on the rock, one (left side of the rock) facing north-northeast and the other (right side) facing east. These two faces are thought to have been pitted and fluted by strong, "sand"- carrying winds from the northeast. This image and PIA01564 [ http://photojournal.jpl.nasa.gov/catalog/PIA01564 ](left eye) make up a stereo pair. Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). |
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Ganges Chasma Sands
PIA03990
Sol (our sun)
Mars Orbiter Camera
| Title |
Ganges Chasma Sands |
| Original Caption Released with Image |
8 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark, windblown sand in the form of dunes and a broad, relatively flat, sand sheet in Ganges Chasma, part of the eastern Valles Marineris trough complex. The winds responsible for these dunes blew largely from the north. Sand dunes on Mars, unlike their Earthly counterparts, are usually dark in tone. This is a reflection of their composition, which includes minerals that are more rich in iron and magnesium than the common silica-rich dunes of Earth. Similar dark sands on Earth are found in volcanic regions such as Iceland and Hawaii. A large dune field of iron/magnesium-rich grains, in the form fragments of the volcanic rock, basalt, occurs south of Moses Lake, Washington, in the U.S. "Location near": 7.7°S, 45.3°W"Image width": ~3 km (~1.9 mi) "Illumination from": lower left "Season": Southern Spring |
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Ice-frosted crater tops on G
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PIA00496
Jupiter
Solid-State Imaging
| Title |
Ice-frosted crater tops on Ganymede |
| Original Caption Released with Image |
Scientists believe that water-ice frosts are the likely cause for the brightening seen around the circular rims of these craters located at a high northern latitude (57 degrees) on Jupiter's moon Ganymede in this image taken by NASA's Galileo spacecraft on September 6, 1996. The image, just recently radioed to Earth from the spacecraft, shows the same kind of bright, high-latitude surface areas as those first seen by the Voyager spacecraft in 1979, but at higher resolution (this image spans about 18 kilometers or 11 miles on a side). Even though the Sun is shining from the south, the north-facing walls of the ridges and craters are brighter than the walls facing the Sun. This is interpreted to mean that the very bright north-facing slopes are covered with surface water-ice frosts, and that these frosts preferentially accumulate in such high-latitude locations. Galileo scientists say that at the high resolution seen in Galileo images, the high-latitude brightness seen by Voyager is partly attributable to frosts forming on cooler, north-facing slopes. The right-hand side of the image is dominated by a north-south line of impact craters, the smallest ones at the top are about 2 kilometers (1.2 miles) in diameter and the large one at the bottom is about 5 kilometers (about 3 miles) in diameter. Ganymede is the largest moon in the solar system, larger than the planet Mercury and nearly the size of Mars. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC. This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo |
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Four Mars Years of South Pol
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PIA04295
Sol (our sun)
Mars Orbiter Camera
| Title |
Four Mars Years of South Polar Changes |
| Original Caption Released with Image |
One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission. The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers. It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed. The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer. The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year (and, of course, most of that retreat takes place during the summer). In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per martian year. Of the two volatile materials one is likely to find in a frozen state on Mars -- water and carbon dioxide -- it is carbon dioxide that is volatile enough to permit scarp retreat rates like those observed by the Mars Orbiter Camera. Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. Since 2001, two additional Mars years have elapsed. A scientific benefit of having a long extended mission for Mars Global Surveyor has been the opportunity to document how the polar cap is changing each year. Four images are shown here, plus an animation at left presenting the four frames in sequence. The location is near 86.3 degrees south latitude, 49.4 degrees west longitude, and the images show the same portion of the south polar, residual cap as it appeared in 1999, 2001, 2003, and 2005. Comparing the images or viewing the animation makes it evident that the landscape of the south polar cap has been changing rapidly over the past four martian years. Each year that Mars Global Surveyor has been in orbit, the landforms of the south polar residual cap have gotten smaller, and the carbon dioxide removed from the cap has not been re-deposited. The implication is that Mars presently has a warm (and possibly warming) climate, with new carbon dioxide going into the atmosphere every year. The other implication is that, at some time in the not-too-distant past, the planet had a colder climate, so that the layers of carbon dioxide could be deposited in the first place. If one takes the rate of scarp retreat and projects it backwards to fill in all of the pits and troughs with the carbon dioxide that has been removed from them, one finds that the colder climate might only have occurred a few centuries to a few tens of thousands of years ago. This kind of time scale is not unlike that of the climate changes that have been recorded on Earth, including the Ice Ages and the smaller fluctuations that have occurred since the last Ice Age (e.g., the "Little Ice Age" of the mid-14th through mid-19th centuries). After the discovery that the pits were enlarging and that we were not seeing carbon-dioxide deposition, it was suggested that interannual variations might be large enough to permit such deposition on a short timescale. However, two Mars years of additional observations show no large magnitude annual differences. Variations that would permit carbon dioxide deposition may require decades. And to see such variations may require many more Mars years of observations by orbiting spacecraft. 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. |
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Four Mars Years of South Pol
…
PIA04295
Sol (our sun)
Mars Orbiter Camera
| Title |
Four Mars Years of South Polar Changes |
| Original Caption Released with Image |
One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission. The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers. It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed. The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer. The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year (and, of course, most of that retreat takes place during the summer). In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per martian year. Of the two volatile materials one is likely to find in a frozen state on Mars -- water and carbon dioxide -- it is carbon dioxide that is volatile enough to permit scarp retreat rates like those observed by the Mars Orbiter Camera. Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. Since 2001, two additional Mars years have elapsed. A scientific benefit of having a long extended mission for Mars Global Surveyor has been the opportunity to document how the polar cap is changing each year. Four images are shown here, plus an animation at left presenting the four frames in sequence. The location is near 86.3 degrees south latitude, 49.4 degrees west longitude, and the images show the same portion of the south polar, residual cap as it appeared in 1999, 2001, 2003, and 2005. Comparing the images or viewing the animation makes it evident that the landscape of the south polar cap has been changing rapidly over the past four martian years. Each year that Mars Global Surveyor has been in orbit, the landforms of the south polar residual cap have gotten smaller, and the carbon dioxide removed from the cap has not been re-deposited. The implication is that Mars presently has a warm (and possibly warming) climate, with new carbon dioxide going into the atmosphere every year. The other implication is that, at some time in the not-too-distant past, the planet had a colder climate, so that the layers of carbon dioxide could be deposited in the first place. If one takes the rate of scarp retreat and projects it backwards to fill in all of the pits and troughs with the carbon dioxide that has been removed from them, one finds that the colder climate might only have occurred a few centuries to a few tens of thousands of years ago. This kind of time scale is not unlike that of the climate changes that have been recorded on Earth, including the Ice Ages and the smaller fluctuations that have occurred since the last Ice Age (e.g., the "Little Ice Age" of the mid-14th through mid-19th centuries). After the discovery that the pits were enlarging and that we were not seeing carbon-dioxide deposition, it was suggested that interannual variations might be large enough to permit such deposition on a short timescale. However, two Mars years of additional observations show no large magnitude annual differences. Variations that would permit carbon dioxide deposition may require decades. And to see such variations may require many more Mars years of observations by orbiting spacecraft. 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. |
|
Four Mars Years of South Pol
…
PIA04295
Sol (our sun)
Mars Orbiter Camera
| Title |
Four Mars Years of South Polar Changes |
| Original Caption Released with Image |
One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission. The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers. It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed. The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer. The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year (and, of course, most of that retreat takes place during the summer). In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per martian year. Of the two volatile materials one is likely to find in a frozen state on Mars -- water and carbon dioxide -- it is carbon dioxide that is volatile enough to permit scarp retreat rates like those observed by the Mars Orbiter Camera. Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. Since 2001, two additional Mars years have elapsed. A scientific benefit of having a long extended mission for Mars Global Surveyor has been the opportunity to document how the polar cap is changing each year. Four images are shown here, plus an animation at left presenting the four frames in sequence. The location is near 86.3 degrees south latitude, 49.4 degrees west longitude, and the images show the same portion of the south polar, residual cap as it appeared in 1999, 2001, 2003, and 2005. Comparing the images or viewing the animation makes it evident that the landscape of the south polar cap has been changing rapidly over the past four martian years. Each year that Mars Global Surveyor has been in orbit, the landforms of the south polar residual cap have gotten smaller, and the carbon dioxide removed from the cap has not been re-deposited. The implication is that Mars presently has a warm (and possibly warming) climate, with new carbon dioxide going into the atmosphere every year. The other implication is that, at some time in the not-too-distant past, the planet had a colder climate, so that the layers of carbon dioxide could be deposited in the first place. If one takes the rate of scarp retreat and projects it backwards to fill in all of the pits and troughs with the carbon dioxide that has been removed from them, one finds that the colder climate might only have occurred a few centuries to a few tens of thousands of years ago. This kind of time scale is not unlike that of the climate changes that have been recorded on Earth, including the Ice Ages and the smaller fluctuations that have occurred since the last Ice Age (e.g., the "Little Ice Age" of the mid-14th through mid-19th centuries). After the discovery that the pits were enlarging and that we were not seeing carbon-dioxide deposition, it was suggested that interannual variations might be large enough to permit such deposition on a short timescale. However, two Mars years of additional observations show no large magnitude annual differences. Variations that would permit carbon dioxide deposition may require decades. And to see such variations may require many more Mars years of observations by orbiting spacecraft. 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. |
|
Four Mars Years of South Pol
…
PIA04295
Sol (our sun)
Mars Orbiter Camera
| Title |
Four Mars Years of South Polar Changes |
| Original Caption Released with Image |
One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission. The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers. It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed. The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer. The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year (and, of course, most of that retreat takes place during the summer). In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per martian year. Of the two volatile materials one is likely to find in a frozen state on Mars -- water and carbon dioxide -- it is carbon dioxide that is volatile enough to permit scarp retreat rates like those observed by the Mars Orbiter Camera. Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. Since 2001, two additional Mars years have elapsed. A scientific benefit of having a long extended mission for Mars Global Surveyor has been the opportunity to document how the polar cap is changing each year. Four images are shown here, plus an animation at left presenting the four frames in sequence. The location is near 86.3 degrees south latitude, 49.4 degrees west longitude, and the images show the same portion of the south polar, residual cap as it appeared in 1999, 2001, 2003, and 2005. Comparing the images or viewing the animation makes it evident that the landscape of the south polar cap has been changing rapidly over the past four martian years. Each year that Mars Global Surveyor has been in orbit, the landforms of the south polar residual cap have gotten smaller, and the carbon dioxide removed from the cap has not been re-deposited. The implication is that Mars presently has a warm (and possibly warming) climate, with new carbon dioxide going into the atmosphere every year. The other implication is that, at some time in the not-too-distant past, the planet had a colder climate, so that the layers of carbon dioxide could be deposited in the first place. If one takes the rate of scarp retreat and projects it backwards to fill in all of the pits and troughs with the carbon dioxide that has been removed from them, one finds that the colder climate might only have occurred a few centuries to a few tens of thousands of years ago. This kind of time scale is not unlike that of the climate changes that have been recorded on Earth, including the Ice Ages and the smaller fluctuations that have occurred since the last Ice Age (e.g., the "Little Ice Age" of the mid-14th through mid-19th centuries). After the discovery that the pits were enlarging and that we were not seeing carbon-dioxide deposition, it was suggested that interannual variations might be large enough to permit such deposition on a short timescale. However, two Mars years of additional observations show no large magnitude annual differences. Variations that would permit carbon dioxide deposition may require decades. And to see such variations may require many more Mars years of observations by orbiting spacecraft. 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. |
|
Four Mars Years of South Pol
…
PIA04295
Sol (our sun)
Mars Orbiter Camera
| Title |
Four Mars Years of South Polar Changes |
| Original Caption Released with Image |
One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission. The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers. It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed. The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer. The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year (and, of course, most of that retreat takes place during the summer). In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per martian year. Of the two volatile materials one is likely to find in a frozen state on Mars -- water and carbon dioxide -- it is carbon dioxide that is volatile enough to permit scarp retreat rates like those observed by the Mars Orbiter Camera. Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. Since 2001, two additional Mars years have elapsed. A scientific benefit of having a long extended mission for Mars Global Surveyor has been the opportunity to document how the polar cap is changing each year. Four images are shown here, plus an animation at left presenting the four frames in sequence. The location is near 86.3 degrees south latitude, 49.4 degrees west longitude, and the images show the same portion of the south polar, residual cap as it appeared in 1999, 2001, 2003, and 2005. Comparing the images or viewing the animation makes it evident that the landscape of the south polar cap has been changing rapidly over the past four martian years. Each year that Mars Global Surveyor has been in orbit, the landforms of the south polar residual cap have gotten smaller, and the carbon dioxide removed from the cap has not been re-deposited. The implication is that Mars presently has a warm (and possibly warming) climate, with new carbon dioxide going into the atmosphere every year. The other implication is that, at some time in the not-too-distant past, the planet had a colder climate, so that the layers of carbon dioxide could be deposited in the first place. If one takes the rate of scarp retreat and projects it backwards to fill in all of the pits and troughs with the carbon dioxide that has been removed from them, one finds that the colder climate might only have occurred a few centuries to a few tens of thousands of years ago. This kind of time scale is not unlike that of the climate changes that have been recorded on Earth, including the Ice Ages and the smaller fluctuations that have occurred since the last Ice Age (e.g., the "Little Ice Age" of the mid-14th through mid-19th centuries). After the discovery that the pits were enlarging and that we were not seeing carbon-dioxide deposition, it was suggested that interannual variations might be large enough to permit such deposition on a short timescale. However, two Mars years of additional observations show no large magnitude annual differences. Variations that would permit carbon dioxide deposition may require decades. And to see such variations may require many more Mars years of observations by orbiting spacecraft. 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. |
|
Recently-Formed Impact Crate
…
PIA04292
Sol (our sun)
Mars Orbiter Camera
| Title |
Recently-Formed Impact Crater |
| Original Caption Released with Image |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a, number of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (figure 2), and in even wider context in a regional mosaic of Viking images (figure 3). 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. |
|
Recently-Formed Impact Crate
…
PIA04292
Sol (our sun)
Mars Orbiter Camera
| Title |
Recently-Formed Impact Crater |
| Original Caption Released with Image |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a, number of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (figure 2), and in even wider context in a regional mosaic of Viking images (figure 3). 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. |
|
Recently-Formed Impact Crate
…
PIA04292
Sol (our sun)
Mars Orbiter Camera
| Title |
Recently-Formed Impact Crater |
| Original Caption Released with Image |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a, number of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (figure 2), and in even wider context in a regional mosaic of Viking images (figure 3). 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. |
|
Recently-Formed Impact Crate
…
PIA04292
Sol (our sun)
Mars Orbiter Camera
| Title |
Recently-Formed Impact Crater |
| Original Caption Released with Image |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a, number of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (figure 2), and in even wider context in a regional mosaic of Viking images (figure 3). 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. |
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Recently-Formed Impact Crate
…
PIA04292
Sol (our sun)
Mars Orbiter Camera
| Title |
Recently-Formed Impact Crater |
| Original Caption Released with Image |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a, number of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (figure 2), and in even wider context in a regional mosaic of Viking images (figure 3). 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. |
|
Recently-Formed Impact Crate
…
PIA04292
Sol (our sun)
Mars Orbiter Camera
| Title |
Recently-Formed Impact Crater |
| Original Caption Released with Image |
Scientists using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft have discovered a crater that appears to have formed on Mars in the past 20 or so Earth years, and have used it and several other similar craters to estimate the present cratering rate on Mars. One of the basic tenets of planetary geology is that impact craters have accumulated on planetary surfaces at roughly a constant rate since the early history of the solar system. This appears to have been the case for small craters on the surface of the Moon, as shown by measurements of the length of time that lunar rocks created by small impacts have been exposed to cosmic rays, as determined by laboratory measurements of samples returned to Earth by the Apollo astronauts. This principle should permit the number of craters found on a planetary surface to be used to determine the age of that surface, if the rate at which new craters form is known. Scientists have previously estimated the cratering rate of Mars by scaling the lunar cratering rate based on the proximity of Mars to the asteroid belt, and by performing calculations based on orbital mechanics. Another way to establish the cratering rate of Mars would be to use long-term observations, say, from orbiting spacecraft, to actually locate new craters. The new crater is located on the southern rim of the summit crater, or caldera, of the intermediate-sized martian volcano, Ulysses Patera. The site was imaged by the Viking 2 orbiter in 1976 (left, an enlarged portion of the image) and in narrow-angle views by the Mars Orbiter Camera in 1999 (center) and 2005 (right). The new crater, about 25 meters (82 feet) across, is marked by a distinct dark, rayed pattern of ejected material, or ejecta, which is seen to have faded somewhat between 1999 and 2005. Ulysses Patera, a volcanic shield about 100 kilometers (62 miles) in diameter volcanic shield, located near 2.5 degrees north latitude, 121.3 degrees west longitude, is one of the Tharsis volcanoes and is partly buried by younger lava flows. The summit caldera is about 55 kilometers (34 miles) in diameter. The amount that the crater's rays faded between 1999 and 2005 can be used to help estimate how many years ago the crater formed. The actual contrast between the ejecta and the undisturbed volcano summit materials is actually much less than it appears to be in these processed images, and the amount of fading is also much less. Images of disturbed surfaces from various parts of Mars, such as dust devil tracks, dark slope streaks and rover tracks, indicate that disturbed surfaces on Mars are dark and that they lighten with time. Using these other examples to estimate how dark the ejecta from the Ulysses crater was originally, and how much it has faded in six years, suggests the crater formed in the early to mid 1980s. The rate at which dark surfaces lighten on Mars is not uniform over the whole planet, but scientists using the Mars Orbiter Camera have found a, number of other craters with dark ejecta that have faded during the Mars Global Surveyor mission. The scientists estimate that these craters probably formed within the past 100 years. Although the sample is very small (the Mars Orbiter Camera narrow angle camera has imaged barely 4 percent of Mars), it appears that the recent cratering rate for craters on Mars 25 to 100 meters (82 to 328 feet) in diameter is about 0.000000003 to 0.000000006 craters per square kilometer (0.39 square mile) per Earth year, which is about five times lower than previous estimates. The site of the new crater is shown in wider context in a comparison of the 1976 Viking image with wide-angle views taken by the Mars Orbiter Camera in 1999 and 2005 (figure 2), and in even wider context in a regional mosaic of Viking images (figure 3). 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. |
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Northeastern Meridiani
PIA04469
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Northeastern Meridiani |
| Original Caption Released with Image |
The remarkable terrain at the "center" of the planet (0 degrees latitude and longitude) is called Meridiani Planum. It hosts a rare occurrence of gray crystalline hematite that will be visited by one of the two Mars Exploration Rovers leaving Earth this June. Just to the ENE of the hematite deposit is the eroded, layered terrain seen in this image, which lacks spectral evidence for hematite. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, 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. Image information: VIS instrument. Latitude 2.3, Longitude 3.6 East (365.4 West). 19 meter/pixel resolution. |
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