Mission Mars Global Surveyor - 4

<h1>PIA00814: Coprates Chasma</h1><div class="PIA00814" lang="en" style="width:176px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Mars Orbiter Camera (MOC) image of a 10 km by 12 km area of Coprates Chasma (14.7 degrees S, 55.8 degrees W), a ridge with a flat upper surface in the center of Coprates Chasma, which is part of the 6000-km-long Valles Marineris. Rock layers are visible just below the ridge. The gray scale (4.8 m/pixel) MOC image was combined with a Viking Orbiter color view of the same area. The faults of a graben offset beds on the slope to the left.<p>Figure caption from Science Magazine<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00814" onclick="window.open(this.href); return false;" title="Voir l'image PIA00814: Coprates Chasma sur le site de la NASA">Voir l'image PIA00814: Coprates Chasma sur le site de la NASA.</a></div>
PIA00814: Coprates Chasma
<h1>PIA00991: Valles Marineris</h1><div class="PIA00991" lang="en" style="width:717px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">MOC images P013_01 and P013_02 were acquired with the low resolution red and blue wide angle cameras at 2:14 PM PDT on October 3, 1997, about 11 minutes after Mars Global Surveyor passed close to the planet for the thirteenth time. To make a color image, a third component (green) was synthesized from the red and blue images. During the imaging period, the spacecraft was canted towards the sun-lit hemisphere by 25°, and the MOC was obliquely viewing features from about 600 to 1000 km (360 to 600 miles) away. The resolution at those distances was between 350 and 600 meters (0.25 to 0.37 miles) per picture element. The image covers an area from 73° to 86° W longitude and 5° N to 10° S).<p>In the image above, north is to the top. The camera is viewing towards the west. The image is the composite of MOC frames P013_01 and P013_02. Because the MOC acquires its images one line at a time, the cant angle towards the sun-lit portion of the planet, the spacecraft orbital velocity, and the spacecraft rotational velocity combine to distort the image slightly. However, the wide angle cameras provide a fairly realistic portrayal of what one would see looking out across Mars from the Orbiter. Notable in this image are the late afternoon clouds and hazes that are concentrated within the Valles Marineris canyon system.<p>Launched on November 7, 1996, Mars Global Surveyor entered Mars orbit on Thursday, September 11, 1997. From the planned 400 km (248 mi) orbit altitude, MOC wide angle images will be 2-4 times higher resolution than these pictures.<p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00991" onclick="window.open(this.href); return false;" title="Voir l'image PIA00991: Valles Marineris sur le site de la NASA">Voir l'image PIA00991: Valles Marineris sur le site de la NASA.</a></div>
PIA00991: Valles Marineris
<h1>PIA00992: Valles Marineris</h1><div class="PIA00992" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">MOC images P013_01 and P013_02 were acquired with the low resolution red and blue wide angle cameras at 2:14 PM PDT on October 3, 1997, about 11 minutes after Mars Global Surveyor passed close to the planet for the thirteenth time. To make a color image, a third component (green) was synthesized from the red and blue images. During the imaging period, the spacecraft was canted towards the sun-lit hemisphere by 25°, and the MOC was obliquely viewing features from about 600 to 1000 km (360 to 600 miles) away. The resolution at those distances was between 350 and 600 meters (0.25 to 0.37 miles) per picture element. The image covers an area from 73° to 86° W longitude and 5° N to 10° S).<p>In both of the two images shown above, north is to the top. In the MOC image, the camera was viewing towards the west.<p>The left image is excepted from a U.S. Geological Survey shaded relief map, showing the footprint of the MOC wide angle color image. The large canyon system (Valles Marineris) spans this view; chaotic terrain is seen at the far right and the eastern-most of the four large Tharsis volcanoes (Ascraeus Mons) is shown in upper left.<p>The right image is the composite of MOC frames P013_01 and P013_02. Because the MOC acquires its images one line at a time, the cant angle towards the sun-lit portion of the planet, the spacecraft orbital velocity, and the spacecraft rotational velocity combine to distort the image slightly. However, the wide angle cameras provide a fairly realistic portrayal of what one would see looking out across Mars from the Orbiter. Notable in this image are the late afternoon clouds and hazes that are concentrated within the canyon system. This image is available at higher resolution as PIA00991.<p>Launched on November 7, 1996, Mars Global Surveyor entered Mars orbit on Thursday, September 11, 1997. From the planned 400 km (248 mi) orbit altitude, MOC wide angle images will be 2-4 times higher resolution than these pictures.<p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00992" onclick="window.open(this.href); return false;" title="Voir l'image PIA00992: Valles Marineris sur le site de la NASA">Voir l'image PIA00992: Valles Marineris sur le site de la NASA.</a></div>
PIA00992: Valles Marineris
<h1>PIA00993: Olympus Mons in Color</h1><div class="PIA00993" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Sections of MOC images P024_01 and P024_02, shown here in color composite form, were acquired with the low resolution red and blue wide angle cameras over a 5 minute period starting when Mars Global Surveyor was at its closest point to the planet at the beginning of its 24th orbit (around 4:00 AM PDT on October 20, 1997). To make this image, a third component (green) was synthesized from the red and blue images. During the imaging period, the camera was pointed straight down towards the martian surface, 176 km (109 miles) below the spacecraft. During the time it took to acquire the image, the spacecraft rose to an altitude of 310 km (193 miles). Owing to data camera scanning rate and data volume constraints, the image was acquired at a resolution of roughly 1 km (0.609 mile) per pixel. The image shown here covers an area from 12° to 26° N latitude and 126° N to 138° W longitude. The image is oriented with north to the top.<p>As has been noted in other MOC releases, Olympus Mons is the largest of the major Tharsis volcanoes, rising 25 km (15.5 miles) and stretching over nearly 550 km (340 miles) east-west. The summit caldera, a composite of as many as seven roughly circular collapse depressions, is 66 by 83 km (41 by 52 miles) across. Also seen in this image are water-ice clouds that accumulate around and above the volcano during the late afternoon (at the time the image was acquired, the summit was at 5:30 PM local solar time). To understand the value of orbital observations, compare this image with the two taken during approach (PIA00929 and PIA00936), that are representative of the best resolution from Earth.<p>Through Monday, October 28, the MOC had acquired a total of 132 images, most of which were at low sun elevation angles. Of these images, 74 were taken with the high resolution narrow angle camera and 58 with the low resolution wide angle cameras. Twenty-eight narrow angle and 24 wide angle images were taken after the suspension of aerobraking. These images, including the one shown above, are among the best returned so far.<p>Launched on November 7, 1996, Mars Global Surveyor entered Mars orbit on Thursday, September 11, 1997. The original mission plan called for using friction with the planet's atmosphere to reduce the orbital energy, leading to a two-year mapping mission from close, circular orbit (beginning in March 1998). Owing to difficulties with one of the two solar panels, aerobraking was suspended in mid-October and is scheduled to resume in mid-November. Many of the original objectives of the mission, and in particular those of the camera, are likely to be accomplished as the mission progresses.<p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA00993" onclick="window.open(this.href); return false;" title="Voir l'image PIA00993: Olympus Mons in Color sur le site de la NASA">Voir l'image PIA00993: Olympus Mons in Color sur le site de la NASA.</a></div>
PIA00993: Olympus Mons in Color
<h1>PIA01031: Evidence for Recent Liquid Water on Mars: Basic Features of Martian Gullies</h1><div class="PIA01031" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Water is the chief agent of weathering and erosion on Earth. Mars is a much drier, colder planet on which liquid water cannot exist very long at the surface because it will immediately begin to boil, evaporate, and freeze--all at the same time. However, new pictures from the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) have provided an astonishing observation which suggests that liquid water may have played a role in shaping some recent gully-like features found on the slopes of various craters, troughs, and other depressions on the red planet.<p>These pictures introduce the basic features of a martian gully. The figure on the left is an example from Mars, the figure on the right is a gully on Earth. In the Earth picture, rain water flowing under and seeping along the base of a recently-deposited volcanic ash layer has created the gully. For Mars, water is not actually seen but is inferred from the landforms and their similarity to examples on Earth.<p>The landforms both on Earth and Mars are divided into three parts: the alcove, the channel, and the apron. Water seeps from between layers of rock on the wall of a cliff, crater, or other type of depression. The alcove forms above the site of seepage as water comes out of the ground and undermines the material from which it is seeping. The erosion of material at the site of seepage causes rock and debris on the slope above this area to collapse and slide downhill, creating the alcove.<p>The channel forms from water and debris running down the slope from the seepage area. The point where the top of the channel meets the bottom of the alcove is, in many cases, the site where seepage is occurring. Channels are probably flushed-clean of debris from time to time by large flash floods of water released from behind an ice barrier that might form at the site of seepage during more quiescent times.<p>The aprons are the down-slope deposits of ice and debris that were moved down the slope and through the channel. Whether any water--likely in the form of ice--persists in these deposits is unknown. The fact that the aprons do not go very far out onto the floors of craters and troughs (e.g., the foreground of the figure on the left) indicates that there is a limit as to how much water actually makes it to the bottom of the slope in liquid form. Most of the water by the time it reaches the bottom of the slope has probably either evaporated or frozen.<p>The MOC image on the left was acquired July 3, 1999, and is located on the south-facing wall of an impact crater near 54.8°S, 342.5°W. The MOC image is illuminated from the upper left; north is toward the upper right. The MOC image covers an area 1.3 km (0.8 mi) wide by 2 km (1.2 mi) long. The pictures from the flank of the Mount St. Helens volcano in Washington (right; large image and inset) were taken by MGSMOC Principal Investigator, Michael C. Malin, in the 1980s after the eruptions of May 1980. They are illuminated from the left; note footprints on left side of the picture for scale, also note the colored bar, which is 30 cm (11.8 in) long.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01031" onclick="window.open(this.href); return false;" title="Voir l'image PIA01031: Evidence for Recent Liquid Water on Mars: Basic Features of Martian Gullies sur le site de la NASA">Voir l'image PIA01031: Evidence for Recent Liquid Water on Mars: Basic Features of Martian Gullies sur le site de la NASA.</a></div>
PIA01031: Evidence for Recent Liquid Water on Mars: Basic Features of Martian Gullies
<h1>PIA01033: Evidence for Recent Liquid Water on Mars: Gullies in Gorgonum Chaos</h1><div class="PIA01033" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><br><a href="/figures/moc2_236b.jpg">Full Resolution Color View</a>.<br><a href="/figures/moc2_236bbw.gif">Full Resolution Grayscale View</a>.<br><b>Warning!</b>These images are very large. These are too long for some web browsers <br>(in these cases, you must save the link to your desktop and view with other software)<br><a href="/figures/moc2_236c.jpg">Larger View</a><br><br><br><p>The first two pictures (top and above left) are from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) and show a series of troughs and layered mesas in the Gorgonum Chaos region of the martian southern hemisphere. The picture at the top of the page is a portion of the picture on the left above. The Viking view (above right) shows the location of the MOC image in the chaotic terrain. Gullies proposed to have been formed by seeping groundwater emanate from a specific layer near the tops of trough walls, particularly on south-facing slopes (south is toward the bottom of each picture). The presence of so many gullies associated with the same layer in each mesa suggests that this layer is particularly effective in storing and conducting water. Such a layer is called an aquifer, and this one appears to be present less than a few hundred meters (few hundred yards) beneath the surface in this region.<p>The MOC pictures were taken on January 22, 2000. The sample at the top of the page is an area 3 kilometers (1.9 miles) wide by 2.6 km (1.6 mi) high. The long view (above left) covers an area 3 kilometers (1.9 miles) wide by 22.6 km (14 mi) long. Sunlight illuminates each scene from the upper left. The images are located near 37.5°S, 170.5°W. The context image (above right) was acquired by the Viking 1 orbiter in 1977 and is illuminated from the upper right, north is up. MOC high resolution images are taken black-and-white (grayscale); the color seen here has been synthesized from the colors of Mars observed by the MOC wide angle cameras and by the Viking Orbiters in the late 1970s.<br><br><p><b>NOTE</b>: A Full Resolution Grayscale view of the release image can be found <a href="/figures/moc2_236bw.gif">here</a>.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01033" onclick="window.open(this.href); return false;" title="Voir l'image PIA01033: Evidence for Recent Liquid Water on Mars: Gullies in Gorgonum Chaos sur le site de la NASA">Voir l'image PIA01033: Evidence for Recent Liquid Water on Mars: Gullies in Gorgonum Chaos sur le site de la NASA.</a></div>
PIA01033: Evidence for Recent Liquid Water on Mars: Gullies in Gorgonum Chaos
<h1>PIA01035: Evidence for Recent Liquid Water on Mars: Gullies in Crater Wall, Noachis Terra</h1><div class="PIA01035" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><a href="/figures/moc2_238b.jpg"></a><br><br><p>Gullies eroded into the wall of a meteor impact crater in Noachis Terra. This high resolution view (top left) from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) shows channels and associated aprons of debris that are interpreted to have formed by groundwater seepage, surface runoff, and debris flow. The lack of small craters superimposed on the channels and apron deposits indicates that these features are geologically young. It is possible that these gullies indicate that liquid water is present within the martian subsurface today.<p>The MOC image was acquired on September 28, 1999. The scene covers an area approximately 3 kilometers (1.9 miles) wide by 6.7 km (4.1 mi) high (note, the aspect ratio is 1.5 to 1.0). Sunlight illuminates this area from the upper left. The image is located near 54.8°S, 342.5°W. The context image (above) shows the location of the MOC image on the south-facing wall of an impact crater approximately 20 kilometers (12 miles) in diameter. The context picture was obtained by the Viking 1 orbiter in 1980 and is illuminated from the upper left. The large mound on the floor of the crater in the context view is a sand dune field. The Mars Orbiter Camera high resolution images are taken black-and-white (grayscale); the color seen here has been synthesized from the colors of Mars observed by the MOC wide angle cameras and by the Viking Orbiters in the late 1970s.<p><b>A brief description of how the color was generated:</b>The MOC narrow angle camera only takes grayscale (black and white) pictures. To create the color versions seen here, we have taken much lower resolution red and blue images acquired by the MOC's wide angle cameras, and by the Viking Orbiter cameras in the 1970s, synthesized a green image by averaging red and blue, and created a pallette of colors that represent the range of colors on Mars. We then use a relationship that correlates color and brightness to assign a color to each gray level. This only a crude approximation of martian color and should only be considered representative of Mars. It is likely Mars would not look like this to a human observer at Mars.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01035" onclick="window.open(this.href); return false;" title="Voir l'image PIA01035: Evidence for Recent Liquid Water on Mars: Gullies in Crater Wall, Noachis Terra sur le site de la NASA">Voir l'image PIA01035: Evidence for Recent Liquid Water on Mars: Gullies in Crater Wall, Noachis Terra sur le site de la NASA.</a></div>
PIA01035: Evidence for Recent Liquid Water on Mars: Gullies in Crater Wall, Noachis Terra
<h1>PIA01040: Evidence for Recent Liquid Water on Mars: Gullies in Sirenum Fossae Trough</h1><div class="PIA01040" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This mosaic of two Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images shows about 20 different gullies coming down the south-facing wall of a trough in the Sirenum Fossae/Gorgonum Chaos region of the martian southern hemisphere. Each channel and its associated fan--or apron--of debris appears to have started just below the same hard, resistant layer of bedrock located approximately 100 meters (about 325 feet) below the top of the trough wall. The layer beneath this hard, resistant bedrock is interpreted to be permeable, which allows ground water to percolate through it and--at the location of this trough--seep out onto the martian surface. The channels and aprons only occur on the south-facing slope of this valley created by faults on each side of the trough. The depression is approximately 1.4 km (0.9 mi) across.<p>The mosaic was constructed from two pictures taken on September 16, 1999, and May 1, 2000. The black line is a gap between the two images that was not covered by MOC. The scene covers an area approximately 5.5 kilometers (3.4 miles) wide by 4.9 km (3.0 mi) high. Sunlight illuminates the area from the upper left. The image is located near 38.5°S, 171.3°W. MOC high resolution images are taken black-and-white (grayscale); the color seen here has been synthesized from the colors of Mars observed by the MOC wide angle cameras and by the Viking Orbiters in the late 1970s.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01040" onclick="window.open(this.href); return false;" title="Voir l'image PIA01040: Evidence for Recent Liquid Water on Mars: Gullies in Sirenum Fossae Trough sur le site de la NASA">Voir l'image PIA01040: Evidence for Recent Liquid Water on Mars: Gullies in Sirenum Fossae Trough sur le site de la NASA.</a></div>
PIA01040: Evidence for Recent Liquid Water on Mars: Gullies in Sirenum Fossae Trough
<h1>PIA01239: Coprates Catena</h1><div class="PIA01239" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This picture of Coprates Catena (14.7°S, 55.8°W) was obtained in the early evening of January 1, 1998 by the Mars Orbiter Camera (MOC), shortly after the Mars Global Surveyor spacecraft began its 80th orbit. The image covers a tiny fraction of the Valles Marineris canyons (that stretch over 4000 km, or 2500 miles, east-west) at very high resolution: it extends only 10 km by 12 km (6 mi by 7.5 mi) and captures features as small as 6 m (20 ft) across. Slopes descend to the north and south (upper and lower part of image, respectively) in broad, debris-filled gullies with intervening rocky spurs. Multiple rock layers, varying from a few to a few tens of meters thick, are visible in the steep slopes on the spurs and gullies. Layered rocks on Earth form from sedimentary processes (such as those that formed the layered rocks now seen in Arizona's Grand Canyon) and volcanic processes (such as layering seen in the Waimea Canyon on the island of Kauai). Both origins are possible for the Martian layered rocks seen in this image. In either case, the total thickness of the layered rocks seen in this image implies a complex and extremely active early history for geologic processes on Mars.<p>Low-resolution Viking color images were used to "colorize" this frame. The process takes the red, green, and blue (RGB) low-resolution images and transforms them to hue (color), saturation (whether the colors are bold or pastel), and intensity (the brightness of the scene), or HSI. The high resolution grayscale image is then used to replace the low-resolution intensity image, and the images are transformed back to RGB. The colors were additionally modified to appear less saturated and more "Earth-like."<p><b> This image does not represent the "true" color of Mars</b><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01239" onclick="window.open(this.href); return false;" title="Voir l'image PIA01239: Coprates Catena sur le site de la NASA">Voir l'image PIA01239: Coprates Catena sur le site de la NASA.</a></div>
PIA01239: Coprates Catena
<h1>PIA01337: Laser Provides First 3-D View of Mars' North Pole</h1><div class="PIA01337" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">This first three-dimensional picture of Mars' north pole enables scientists to estimate the volume of its water ice cap with unprecedented precision, and to study its surface variations and the heights of clouds in the region for the first time.<p>Approximately 2.6 million of these laser pulse measurements were assembled into a topographic grid of the north pole with a spatial resolution of 0.6 miles (one kilometer) and a vertical accuracy of 15-90 feet (5-30 meters).<p>The principal investigator for MOLA is Dr. David E. Smith of Goddard. The MOLA instrument was designed and built by the Laser Remote Sensing Branch of Laboratory for Terrestrial Physics at Goddard. The Mars Global Surveyor Mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for the NASA Office of Space Science.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01337" onclick="window.open(this.href); return false;" title="Voir l'image PIA01337: Laser Provides First 3-D View of Mars' North Pole sur le site de la NASA">Voir l'image PIA01337: Laser Provides First 3-D View of Mars' North Pole sur le site de la NASA.</a></div>
PIA01337: Laser Provides First 3-D View of Mars' North Pole
<h1>PIA01432: Opposition Surge: Sunlight Glinting off Mars</h1><div class="PIA01432" lang="en" style="width:624px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Mars Global Surveyor was presented with a unique opportunity February 13-18, 1998, to image sunlight glinting off of the surface and atmospheric haze of Mars. Orbits 130-137 were devoted to obtaining MOC images of this effect, also known as opposition surge. During each orbit in mid-February, the Mars Global Surveyor spacecraft passed close to and through the line between the Sun and the center of Mars. In other words, the phase angle (angle between the Sun's incident light and the direction from the surface to the spacecraft) was near zero degrees. The sunlight reflecting from Mars near the zero phase angle produces the rare sun-glint phenomenon. The size and brightness of the glint depends on the physical properties of the surface (dust, sand, and rock distribution) and the atmosphere (haze/suspended dust). Studies of these images are expected to yield important information that can be compared with thermal emission observations.<p>The picture is a color composite of MOC images 13601 (red wide angle) and 13602 (blue wide angle). The green-color band is synthesized from the red and blue using a relationship well-understood from Viking images of the late 1970s. The large, dark region near the top-center of the picture is Sinus Meridiani. The circular feature at the upper right is the impact basin, Schiaparelli. The opposition surge feature --the sun glint-- is centered around 21.0°S latitude, 4.1°W longitude.<p>The two images were taken on Mars Global Surveyor's 136th orbit on February 18, 1998. Orbit 136 was the second-to-last orbit on which MOC obtained images of Mars during the first aerobraking phase (AB-1) of the mission. MOC was off between the end of AB-1 on February 19, 1998, until the start of Science Phasing Orbit-1 phase (SPO-1), which began March 28 and ended April 28, 1998.<p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01432" onclick="window.open(this.href); return false;" title="Voir l'image PIA01432: Opposition Surge: Sunlight Glinting off Mars sur le site de la NASA">Voir l'image PIA01432: Opposition Surge: Sunlight Glinting off Mars sur le site de la NASA.</a></div>
PIA01432: Opposition Surge: Sunlight Glinting off Mars
<h1>PIA01436: Detailed Cloud Patterns in Martian Northern Hemisphere</h1><div class="PIA01436" lang="en" style="width:434px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Cold and cloudy mornings; cool, hazy afternoons. High winds aloft and weather fronts moving slowly to the east. It is winter in the Martian northern hemisphere. One of the many reasons to study Mars is that, at times, its weather is very "Earth-like." At this time of the Martian year, clouds are abundant, especially in the morning and especially in the high northern latitudes. Clouds and fogs are also observed in low-lying areas farther to the south, in some lowlands they are as far south as the equator.<p>The above color composite images, obtained by Mars Global Surveyor's camera on June 4, 1998, illustrate this Martian "weather report." Most of the thick, white clouds seen here occur north of latitude 35°N (roughly equivalent to Albuquerque NM, Memphis TN, and Charlotte, NC). Fog (seen as bright orange because it is lighter than the ground but some of the ground is still visible) occupies the lowest portions of the Kasei Valles outflow channel around 30°N and at 25°N.<p>Several different types of cloud features are seen. The repetitious, wash-board pattern of parallel lines are "gravity wave clouds". These commonly form, in the lee--downwind side-- of topographic features such as mountain ranges (on Earth) or crater rims (on Mars), under very specific atmospheric conditions (low temperatures, high humidity, and high wind speeds). In this area, the wave clouds are lower in the atmosphere than some of the other clouds. These other clouds show attributes reflecting more the regional weather pattern, occasionally showing the characteristic "slash" shape (southwest to northeast) of a weather front. These clouds probably contain mostly crystals of water ice but, depending on the temperature at high altitude (and more likely closer to the pole), some could also contain frozen carbon dioxide ("dry ice").<p>MOC images 34501 (the red wide angle image) and 34502 (the blue wide angle image) were obtained on Mars Global Surveyor's 345th orbit about the planet. The pictures were taken around 5: 34 p.m. PDT on June 4, 1998. Winter in the northern hemisphere began in mid-February, 1998, and continues to mid-July, 1998.<p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01436" onclick="window.open(this.href); return false;" title="Voir l'image PIA01436: Detailed Cloud Patterns in Martian Northern Hemisphere sur le site de la NASA">Voir l'image PIA01436: Detailed Cloud Patterns in Martian Northern Hemisphere sur le site de la NASA.</a></div>
PIA01436: Detailed Cloud Patterns in Martian Northern Hemisphere
<h1>PIA01457: Elysium Mons Volcanic Region</h1><div class="PIA01457" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">On July 4, 1998--the first anniversary of the Mars Pathfinder landing--Mars Global Surveyor's latest images were radioed to Earth with little fanfare. The images received on July 4, 1998, however, were very exciting because they included a rare crossing of the summit caldera of a major martian volcano. Elysium Mons is located at 25°N, 213°W, in the martian eastern hemisphere. Elysium Mons is one of three large volcanoes that occur on the Elysium Rise-- the others are Hecates Tholus (northeast of Elysium Mons) and Albor Tholus (southeast of Elysium Mons). The volcano rises about 12.5 kilometers (7.8 miles) above the surrounding plain, or about 16 kilometers (9.9 miles) above the martian datum-- the "zero" elevation defined by average martian atmospheric pressure and the planet's radius.<p>Elysium Mons was discovered by Mariner 9 in 1972. It differs in a number of ways from the familiar Olympus Mons and other large volcanoes in the Tharsis region. In particular, there are no obvious lava flows visible on the volcano's flanks. The lack of lava flows was apparent from the Mariner 9 images, but the new MOC high resolution image--obtained at 5.24 meters (17.2 feet) per pixel--illustrates that this is true even when viewed at higher spatial resolution.<p>Elysium Mons has many craters on its surface. Some of these probably formed by meteor impact, but many show no ejecta pattern characteristic of meteor impact. Some of the craters are aligned in linear patterns that are radial to the summit caldera--these most likely formed by collapse as lava was withdrawn from beneath the surface, rather than by meteor impact. Other craters may have formed by explosive volcanism. Evidence for explosive volcanism on Mars has been very difficult to identify from previous Mars spacecraft images. This and other MOC data are being examined closely to better understand the nature and origin of volcanic features on Mars.<p>The three MOC images, 40301 (red wide angle), 40302 (blue wide angle), and 40303 (high resolution, narrow angle) were obtained on Mars Global Surveyor's 403rd orbit around the planet around 9:58 - 10:05 p.m. PDT on July 2, 1998. The images were received and processed at Malin Space Science Systems (MSSS) around 4:00 p.m. PDT on July 4, 1998.<p>This image: Elysium Volcanic Region as seen by MOC on July 2, 1998. Volcano near top center is Hecates Tholus--note bright clouds off its northeast flank. Volcano near center is Elysium Mons; volcano toward lower right is Albor Tholus. Red channel is MOC red wide angle image 40301, the blue channel is MOC blue wide angle image 40302, and the green channel is synthesized by averaging the red and blue bands. Image is an orthographic projection centered at 24.85°N, 213.25°W. The scale at the center of the projection is 4.65 kilometers (2.9 miles) per pixel. North is up, illumination is from the lower right.<p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01457" onclick="window.open(this.href); return false;" title="Voir l'image PIA01457: Elysium Mons Volcanic Region sur le site de la NASA">Voir l'image PIA01457: Elysium Mons Volcanic Region sur le site de la NASA.</a></div>
PIA01457: Elysium Mons Volcanic Region
<h1>PIA01476: Olympus Mons, 1998 (color)</h1><div class="PIA01476" lang="en" style="width:573px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Olympus Mons is a mountain of mystery. Taller than three Mount Everests and about as wide as the entire Hawaiian Island chain, this giant volcano is nearly as flat as a pancake. That is, its flanks typically only slope 2° to 5°.<p>The Mars Orbiter Camera (MOC) obtained this spectacular wide-angle view of Olympus Mons on Mars Global Surveyor's 263rd orbit, around 10:40 p.m. PDT on April 25, 1998. In the view presented here, north is to the left and east is up. The spacecraft was traveling from north to south (left to right). Although the camera looks straight down (towards the nadir) and cannot be pointed to the side, the wide angle camera has such a large field of view (it sees from horizon to horizon) that, in effect, it provides side looking views. Unlike some other MOC images, that have had to be warped to provide a view as if seen from a certain direction and altitude, this image shows what the camera saw without additional processing. It is easy to imagine that you are looking out a window at the surface of Mars from about 900 km (560 miles) up.<p>The image was taken on a cool, crisp winter morning. The west side of the volcano (lower portion of view, above) was clear and details on the surface appear very sharp. The skies above the plains to the east of Olympus Mons (upper portion of view) were cloudy. Clouds were lapping against the lower east flanks of this 26 kilometers (16 miles) high volcano, but the summit skies were clear.<p>When Mars Global Surveyor attains its Mapping Orbit in March 1999, the MOC wide angle camera system will be used to make daily, global maps of martian clouds and weather systems. The wide angle images will resemble weather satellite pictures of Earth, and will help the Mars science teams plan their observations and test computer-driven Mars weather prediction models.<p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01476" onclick="window.open(this.href); return false;" title="Voir l'image PIA01476: Olympus Mons, 1998 (color) sur le site de la NASA">Voir l'image PIA01476: Olympus Mons, 1998 (color) sur le site de la NASA.</a></div>
PIA01476: Olympus Mons, 1998 (color)
<h1>PIA01676: "Happy Face" Crater Greets MGS at the Start of the Mapping</h1><div class="PIA01676" lang="en" style="width:525px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>The story of the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor(MGS) spacecraft began with a proposal to NASA in 1985. The first MOC flew on Mars Observer, a spacecraft that was lost before it reached the red planet in 1993. Now, after 14 years of effort, a MOC has finally been placed in the desired mapping orbit. The MOC team's happiness is perhaps best expressed by the planet Mars itself. On the first day of the Mapping Phase of the MGS mission--during the second week of March 1999--MOC was greeted with this view of "Happy Face Crater" (center right) smiling back at the camera from its location on the east side of Argyre Planitia. This crater is officially known as Galle Crater, and it is about 215 kilometers (134 miles) across. The picture was taken by the MOC's red and blue wide angle cameras. The bluish-white tone is caused by wintertime frost. Illumination is from the upper left. For more information and Viking Orbiter views of "Happy Face Crater," see <a href="http://www.msss.com/education/happy_face/happy_face.html">http://www.msss.com/education/happy_face/happy_face.html</a>.</p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01676" onclick="window.open(this.href); return false;" title="Voir l'image PIA01676: "Happy Face" Crater Greets MGS at the Start of the Mapping sur le site de la NASA">Voir l'image PIA01676: "Happy Face" Crater Greets MGS at the Start of the Mapping sur le site de la NASA.</a></div>
PIA01676: "Happy Face" Crater Greets MGS at the Start of the Mapping
<h1>PIA01692: Western Melas and Candor Chasms, Valles Marineris</h1><div class="PIA01692" lang="en" style="width:450px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>During its March 1999 operations, the Mars Orbiter Camera (MOC) on board the Mars Global Surveyor (MGS) captured this stunning wide-angle camera view of the western portions of Melas and Candor Chasms in the Valles Marineris canyon system. This view covers an area that is about 80 kilometers (50 miles) wide and 220 kilometers (137 miles) long. Melas Chasma is located at the bottom of the image, Candor at the top. Hints of layers in the canyon walls are evident in this image. Color and albedo (brightness)variations on the floors of each chasm indicate the relative distribution of dark sand and brighter sediments and/or rocks. Dark sand on the floor of Melas Chasma was also seen by MOC in March 1999 <a href="http://www.msss.com/mars/global_surveyor/camera/images/3_25_99_melas/index.html">(see MOC2-104)</a> and bright layered material was observed in Candor Chasma in April 1998 <a href="http://www.msss.com/mars/global_surveyor/camera/images/7_20_98_marineris_rel/index.html">(see MOC2-59)</a>.</p><p>The colors shown here are not true colors as they would appear to the human eye. The MOC has cameras that obtain images in red and blue portions of the visible spectrum; the green portion is synthesized using the combined average values of the red and blue channels (a relationship understood from Viking Orbiter imaging in the 1970s). Illumination is from the upper left.</p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01692" onclick="window.open(this.href); return false;" title="Voir l'image PIA01692: Western Melas and Candor Chasms, Valles Marineris sur le site de la NASA">Voir l'image PIA01692: Western Melas and Candor Chasms, Valles Marineris sur le site de la NASA.</a></div>
PIA01692: Western Melas and Candor Chasms, Valles Marineris
<h1>PIA01887: MGS Mars Orbiter Camera: 10 Years In Space</h1><div class="PIA01887" lang="en" style="width:596px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>7 November 2006<br />Mars Global Surveyor (MGS) was launched 10 years ago today, on 7 November 1996. The spacecraft reached Mars on 12 September 1997, and has been observing the ever-changing red planet over the course of the past 5 martian years. <p><p>The Mars Orbiter Camera (MOC) has spent 10 years in the near vacuum of space-not bad, considering that the Primary Mission, at the time of launch, was expected to end in early 2000. Since September 1997, MOC has been acquiring new images that highlight the geology and meteorology of Mars; more than 240,000 images have been returned to Earth. A recent example, from 15 October 2006, is shown here. <p><p>Two annular (i.e., somewhat circular) clouds are seen in the upper left corner of this mosaic of MOC wide angle camera daily global mapping images. To the right of the picture's center is the martian north polar cap. The image has a scale of about 7.5 kilometers (4.7 miles) per pixel. Annular clouds are common in mid-northern summer in the north polar region, and may result from eddy currents in the lower atmosphere. The appearance of such clouds happens every year; this year they came like clockwork within a two-week forecasted period, based on the previous 4 martian years of experience gained from MGS MOC daily global imaging. <p><p>Despite their superficial resemblance to Earth-orbiting satellite views of hurricanes, these cloud features are not the result of strong winds, and they typically dissipate later in the day. The pictures used to make this mosaic were acquired less than 2 days before the MOC was turned off for MGS's fifth Mars-Earth Solar Conjunction period. During Conjunction, Mars was on the other side of the Sun, relative to Earth, and thus MGS could not transmit data (through the Sun) during the second half of October. <p><p>Examples of north polar annular clouds seen in previous Mars years were featured by the MGS MOC team in September 2005: <a href="http://www.msss.com/mars_images/moc/2005/09/12/index.html">"Celebrating 8 Years at Mars: Repeated Weather Events."</a> To review the MGS launch of 10 years ago, one can visit the NASA Kennedy Space Center web site, which includes pictures and video at: <a href="http://science.ksc.nasa.gov/payload/missions/mgs/video.html" target="_blank">http://science.ksc.nasa.gov/payload/missions/mgs/video.html</a>. Video clips of the launch and many movies and videos from the earlier phases of the MGS mission can be reviewed at the Jet Propulsion Laboratory web site at:<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01887" onclick="window.open(this.href); return false;" title="Voir l'image PIA01887: MGS Mars Orbiter Camera: 10 Years In Space sur le site de la NASA">Voir l'image PIA01887: MGS Mars Orbiter Camera: 10 Years In Space sur le site de la NASA.</a></div>
PIA01887: MGS Mars Orbiter Camera: 10 Years In Space
<h1>PIA01928: Mars Polar Cap During Transition Phase Instrument Checkout</h1><div class="PIA01928" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>During the last week of September and the first week or so of October 2006, scientific instruments on NASA's Mars Reconnaissance Orbiter were turned on to acquire test information during the transition phase leading up to full science operations. The mission's primary science phase will begin the first week of November 2006, following superior conjunction. (Superior conjunction is where a planet goes behind the sun as viewed from Earth.) Since it is very difficult to communicate with a spacecraft when it is close to the sun as seen from Earth, this checkout of the instruments was crucial to being ready for the primary science phase of the mission.</p><p>Throughout the transition-phase testing, the Mars Color Imager (MARCI) acquired terminator (transition between nighttime and daytime) to terminator swaths of color images on every dayside orbit, as the spacecraft moved northward in its orbit. The south polar region was deep in winter shadow, but the north polar region was illuminated the entire Martian day. During the primary mission, such swaths will be assembled into global maps that portray the state of the Martian atmosphere -- its weather -- as seen every day and at every place at about 3 p.m. local solar time. After the transition phase completed, most of the instruments were turned off, but the Mars Climate Sounder and MARCI have been left on. Their data will be recorded and played back to Earth following the communications blackout associated with conjunction.</p><p>Combined with wide-angle image mosaics taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor at 2 p.m. local solar time, the MARCI maps will be used to track motions of clouds.</p><p>This image is a composite mosaic of four polar views of Mars, taken at midnight, 6 a.m., noon, and 6 p.m. local Martian time. This is possible because during summer the sun is always shining in the polar region. It shows the mostly water-ice perennial cap (white area), sitting atop the north polar layered materials (light tan immediately adjacent to the ice), and the dark circumpolar dunes. This view shows the region poleward of about 72 degrees north latitude. The data were acquired at about 900 meters (about 3,000 feet) per pixel. Three channels are shown here, centered on wavelengths of 425 nanometers, 550 nanometers and 600 nanometers.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01928" onclick="window.open(this.href); return false;" title="Voir l'image PIA01928: Mars Polar Cap During Transition Phase Instrument Checkout sur le site de la NASA">Voir l'image PIA01928: Mars Polar Cap During Transition Phase Instrument Checkout sur le site de la NASA.</a></div>
PIA01928: Mars Polar Cap During Transition Phase Instrument Checkout
<h1>PIA01929: Map of Context Camera's North Polar Coverage During Checkout</h1><div class="PIA01929" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>In October 2006, Northern Mars is near the middle of its summer, and the continued southern movement of the sun will have two main impacts on imaging: The illumination will get worse as eventually the entire polar region will be in darkness during winter, and northern hemispheric dust storms and polar cloudiness will obscure the surface. Because now is the best time to be imaging the north polar region until 2008, the team using the Context Camera on NASA's Mars Reconnaissance Orbiter is devoting much of its imaging resources to acquiring images of the polar region. This image shows a north polar mosaic from the orbiter's Mars Color Imager inscribed with rectangles indicating the coverage acquired by Context Camera in less than two weeks of September and October, 2006. Following conjunction (when Mars is nearly behind the sun from Earth's perspective), the team will devote as much of November as the atmosphere permits to imaging the polar region.Marked in red on this map is the footprint of the Context Camera image shown at <a href="/catalog/PIA01930">PIA01930</a>.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA01929" onclick="window.open(this.href); return false;" title="Voir l'image PIA01929: Map of Context Camera's North Polar Coverage During Checkout sur le site de la NASA">Voir l'image PIA01929: Map of Context Camera's North Polar Coverage During Checkout sur le site de la NASA.</a></div>
PIA01929: Map of Context Camera's North Polar Coverage During Checkout
<h1>PIA02006: Apollinaris Patera, Mars</h1><div class="PIA02006" lang="en" style="width:429px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This month (April 1999), the Mars Global Surveyor Mars Orbiter Camera (MOC) passed over the Apollinaris Patera volcano and captured a patch of bright clouds hanging over its summit in the early martian afternoon. This ancient volcano is located near the equator and--based on observations from the 1970s Viking Orbiters--is thought to be as much as 5 kilometers (3 miles) high. The caldera--the semi-circular crater at the volcano summit--is about 80 kilometers (50 miles) across.</p><p>The color in this picture was derived from the MOC red and blue wide angle camera systems and does not represent true color as it would appear to the human eye (that is, if a human were in a position to be orbiting around the red planet). Illumination is from the upper left.</p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02006" onclick="window.open(this.href); return false;" title="Voir l'image PIA02006: Apollinaris Patera, Mars sur le site de la NASA">Voir l'image PIA02006: Apollinaris Patera, Mars sur le site de la NASA.</a></div>
PIA02006: Apollinaris Patera, Mars
<h1>PIA02045: May 1999 Dust Storm in Valles Marineris</h1><div class="PIA02045" lang="en" style="width:558px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Mars Global Surveyor's (MGS) Mars Orbiter Camera (MOC) captured this view of a dust storm within the Ius and Melas Chasms of the Valles Marineris trough system on May 16, 1999.</p><p>The dust storm is seen in the lower 1/3 of the image. It occurs at the junction between eastern Ius Chasma and western Melas Chasma. The apparent motion of the storm is approximately from the south (bottom of image) toward the north. The dust cloud forms a sharp front along its northern margin, which is seen along the north wall of Ius and Melas Chasms--in fact, at the time the image was taken, the dust had advanced up over the north wall of Melas Chasma (upper portion of lower right third of image) and was advancing across the upland that separates this chasm from western Candor Chasma. For a clear-atmosphere view of western Candor and Melas Chasms, see <a href="http://www.msss.com/mars/global_surveyor/camera/images/3_25_99_vmcolor/index.html">"Western Melas and Candor Chasms, Valles Marineris, MOC2-105, 25 March 1999"</a>.</p><p>For scale, note that the large crater south of Hebes Chasma, Perrotin, is about 95 kilometers (59 miles) across. Bluish-white clouds in the image are interpreted to consist of water ice. The pink/red clouds of the dust storm occur closer to the ground, at a lower altitude than the water ice clouds.</p><p>One of the most interesting aspects of this dust storm is that Valles Marineris was observed to have a dust storm at exactly the same time of year, one Martian year ago. During its approach to Mars, MOC obtained a picture of the planet on July 2,1997, just prior to the Mars Pathfinder landing. At the time, it was winter in the southern hemisphere, and dust clouds were observed within Valles Marineris. The picture is seen in <a href="http://www.msss.com/mars/global_surveyor/camera/images/c9/index.html">"Mars Orbiter Camera Views Mars Pathfinder Landing Site,MOC2-1, 3 July 1997"</a>. It will be interesting to see if similar storms occur within the Valles Marineris 1 and 2 Mars years hence. The next times will be in early April 2001 and mid-February 2003.</p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02045" onclick="window.open(this.href); return false;" title="Voir l'image PIA02045: May 1999 Dust Storm in Valles Marineris sur le site de la NASA">Voir l'image PIA02045: May 1999 Dust Storm in Valles Marineris sur le site de la NASA.</a></div>
PIA02045: May 1999 Dust Storm in Valles Marineris
<h1>PIA02049: Regional View of the Tharsis Volcanoes</h1><div class="PIA02049" lang="en" style="width:768px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><br>The volcanoes of the Tharsis region are highlighted by this color image mosaic obtained on a single martian afternoon by the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft. Olympus Mons dominates the upper left corner--it is one of the largest known volcanoes and is nearly 550 km (340 miles) wide. The grayscale image on the right shows the name of each volcano in the scene.<p>The white or bluish-white features are clouds. Clouds are common over the larger Tharsis volcanoes in mid-afternoon. The four largest volcanoes are more than 15 km (9 mi) high. Viewed from Earth by telescope before any spacecraft had visited the planet, astronomers often described a "W"-shaped white cloud over the Tharsis region. This "W" was actually the result of seeing the combined effects of bright clouds hanging over the Ascraeus, Pavonis, Arsia, and Olympus volcanoes. The clouds result when warm air containing water vapor rises up the slopes of each volcano, cools at the higher altitude, and causes the water vapor to freeze and form a cloud of ice crystals.<p>Pavonis Mons lies on the martian equator, north is up, and sunlight is illuminating the scene from the left. The picture is a mosaic of red and blue filter images taken on three consecutive orbits. The slightly blurred appearance of the left side of Arsia Mons results from distortion toward the edges of the images used to make the mosaic. To remove the blur, an image obtained on another day would be added to the mosaic--however, this image would not match well because the cloud patterns will have changed by the next day. Mosaics such as the one shown here are used to monitor changes in martian weather and to plan future observations.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02049" onclick="window.open(this.href); return false;" title="Voir l'image PIA02049: Regional View of the Tharsis Volcanoes sur le site de la NASA">Voir l'image PIA02049: Regional View of the Tharsis Volcanoes sur le site de la NASA.</a></div>
PIA02049: Regional View of the Tharsis Volcanoes
<h1>PIA02066: Global Weather</h1><div class="PIA02066" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Twelve orbits a day provide the MOC wide angle cameras a global "snapshot" of weather patterns across the planet. Here, bluish-white water ice clouds hang above the Tharsis volcanoes. The map is a mosaic of 24 images taken on a single northern summer day in April 1999.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02066" onclick="window.open(this.href); return false;" title="Voir l'image PIA02066: Global Weather sur le site de la NASA">Voir l'image PIA02066: Global Weather sur le site de la NASA.</a></div>
PIA02066: Global Weather
<h1>PIA02067: Dust storm</h1><div class="PIA02067" lang="en" style="width:720px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>MOC wide angle cameras captured a dust storm advancing across the northern plains toward Tempe Terra on August 22, 1998.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02067" onclick="window.open(this.href); return false;" title="Voir l'image PIA02067: Dust storm sur le site de la NASA">Voir l'image PIA02067: Dust storm sur le site de la NASA.</a></div>
PIA02067: Dust storm
<h1>PIA02079: Tharsis and Marineris</h1><div class="PIA02079" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image is extracted from the global view shown in Slide #1. It features the Tharsis volcanoes (mostly covered by bluish-white water ice clouds) and the Valles Marineris trough system (to the right). This is a mosaic of global color images obtained on a single martian day in April 1999.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02079" onclick="window.open(this.href); return false;" title="Voir l'image PIA02079: Tharsis and Marineris sur le site de la NASA">Voir l'image PIA02079: Tharsis and Marineris sur le site de la NASA.</a></div>
PIA02079: Tharsis and Marineris
<h1>PIA02096: Southern Mars: It's Spring!</h1><div class="PIA02096" lang="en" style="width:552px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>August 2, 1999, marks the spring equinox for the martian southern hemisphere. It is also the start of autumn for regions north of the equator. Winter in the south has finally come to a close, and the seasonal frosts of the wintertime south polar cap are retreating. Small, local dust storms frequently occur along the margins of the polar cap, as the colder air blowing off the cap moves northward into warmer regions.</p><p>The wide angle camera view of Mars shown here was obtained by the Mars Global Surveyor Mars Orbiter Camera in late July 1999, about 1 week before the start of southern spring. The frosty, retreating south polar cap (white) is seen in the lower quarter of the image, and wisps of dust storm clouds (grayish-orange in this view) occur just above the cap at the lower left. The southern most of the large environmental changes volcanoes, Arsia Mons, is seen at the upper left. Arsia Mons is about 350 kilometers(~220 miles) across.</p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02096" onclick="window.open(this.href); return false;" title="Voir l'image PIA02096: Southern Mars: It's Spring! sur le site de la NASA">Voir l'image PIA02096: Southern Mars: It's Spring! sur le site de la NASA.</a></div>
PIA02096: Southern Mars: It's Spring!
<h1>PIA02164: Arsia and Phobos</h1><div class="PIA02164" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p><a href="/figures/PIA02164_fig1.jpg"></a><b><br />Annotated View of Arsia and Phobos</b></p><p>6 February 2006<br />This pair of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) color images shows early autumn clouds over the Arsia Mons volcano, plus the shadow of the innermost of the two martain moons, Phobos. The picture on the left is taken from the MOC daily global map acquired at 7.5 km (~4.7 mi) per pixel on 28 January 2006, about a week after the start of southern autumn. The picture on the right was taken at the same time, but at a higher resolution of 489 m (1604 ft) per pixel. </p><p>Both pictures are composites of MOC red and blue wide angle images, and both are oriented such that north is up and east is to the right. Arsia Mons and the other large Tharsis volcanoes commonly develop afternoon orographic (i.e., topographically-controlled) water ice clouds at this time of year. The equatorial Tharsis volcano, Pavonis Mons, is also under a deck of water ice clouds; it is located toward the upper right corner of the left, lower-resolution image. </p><p>Sunlight glints off the dusty surface and the clouds and aerosols in the atmosphere, producing the bright diagonal streak located just southeast (lower right) of Arsia Mons. A water ice haze is seen on the left side of the lower-resolution image. The dark oval to the northeast of Arsia Mons, as noted above, is the shadow of Phobos.</p><p>Location near: 9°S, 121°W <br />Image width: 100 km scale bar = ~62 mi; 300 km bar = ~186 mi <br />Illumination from: upper left <br />Season: Southern Autumn </p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02164" onclick="window.open(this.href); return false;" title="Voir l'image PIA02164: Arsia and Phobos sur le site de la NASA">Voir l'image PIA02164: Arsia and Phobos sur le site de la NASA.</a></div>
PIA02164: Arsia and Phobos
<h1>PIA02305: Late Summer Storms Over the Mars North Polar Region</h1><div class="PIA02305" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;">Storm clouds have been brewing over the north polar cap of Mars since the last week of June 1999. During the month of July, summer was ending; autumn began at the start of August. The wide angle cameras of the Mars Global Surveyor(MGS) Mars Orbiter Camera (MOC) have been documenting the changing weather patterns of the red planet nearly every day since the Mapping Phase of the mission began in March 1999. These images are showing many more details about martian weather than had been previously recorded. Mars is a dynamic planet, with weather systems as complex and exciting as the Earth's.<p>The four still-frame images (above) show the evolution of a storm system that developed over the martian north polar region on June 30, 1999. Each picture was taken approximately 2 hours later than the previous. The north polar ice cap is the white feature at the center of each frame. Clouds that appear white consist mainly of water ice, clouds that appear orange/brown contain dust.<p>This particular storm system lasted well into the next day--July 1, 1999. A total of 23 red and 23 blue camera images were used to create a time-lapsed "movie" that displays the development and evolution of this storm over the two-day period. Of great interest are the "curling" of the clouds behind the largest of the storms--this indicates a flow vortex that follows the storm front that is moving toward the top/upper right of the frame--and the correlation of white water-ice clouds with orange/brown dust clouds. High surface winds must have raised dust and mixed it with water vapor in the air over the summer-time polar cap to create this effect. To view the "movie," click or download to your desktop the following<a href="/figures/PIA02305.mpg"> 2.2 MByte MPG file.</a><p>Storms similar to those shown here were observed to continue throughout the month of July and into August. Over the next several months, the north polar cap will grow dark as the region transitions through autumn and into winter. When northern winter begins in December 1999, this region will be dark and obscured by clouds.<p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02305" onclick="window.open(this.href); return false;" title="Voir l'image PIA02305: Late Summer Storms Over the Mars North Polar Region sur le site de la NASA">Voir l'image PIA02305: Late Summer Storms Over the Mars North Polar Region sur le site de la NASA.</a></div>
PIA02305: Late Summer Storms Over the Mars North Polar Region
<h1>PIA02307: TES overlayed on MOLA DEM</h1><div class="PIA02307" lang="en" style="width:551px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>This image is TES thermal data (Orbit 222) overlayed on the MOLA DEM. The color scale is TES T18-T25, which is a cold spot index. The grey scale is MOLA elevation in kilometers. Most cold spots can be attributed to surface spectral emissivity effects. Regions that are colored black-violet-blue have near unity emissivity and are coarse grained CO2. Regions that are yellow-red are fined grained CO2. The red-white spot located approximately 300W85N is our most likely candidate for a CO2 snow storm.</p><br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02307" onclick="window.open(this.href); return false;" title="Voir l'image PIA02307: TES overlayed on MOLA DEM sur le site de la NASA">Voir l'image PIA02307: TES overlayed on MOLA DEM sur le site de la NASA.</a></div>
PIA02307: TES overlayed on MOLA DEM
<h1>PIA02325: Have a Nice Spring! MOC Revisits "Happy Face" Crater</h1><div class="PIA02325" lang="en" style="width:800px;text-align:left;margin:auto;background-color:#000;padding:10px;max-height:150px;overflow:auto;"><p>Smile! Spring has sprung in the martian southern hemisphere. With it comes the annual retreat of the winter polar frost cap. This view of "Happy Face Crater"--officially named "Galle Crater"--shows patches of white water ice frost in and around the crater's south-facing slopes. Slopes that face south will retain frost longer than north-facing slopes because they do not receive as much sunlight in early spring. This picture is a composite of images taken by the Mars Global Surveyor Mars Orbiter Camera (MOC) red and blue wide angle cameras. The wide angle cameras were designed to monitor the changing weather, frost, and wind patterns on Mars. Galle Crater is located on the east rim of the Argyre Basin and is about 215 kilometers (134 miles) across. In this picture, illumination is from the upper left and north is up.</p><p>Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.<br /><br /><a href="http://photojournal.jpl.nasa.gov/catalog/PIA02325" onclick="window.open(this.href); return false;" title="Voir l'image PIA02325: Have a Nice Spring! MOC Revisits "Happy Face" Crater sur le site de la NASA">Voir l'image PIA02325: Have a Nice Spring! MOC Revisits "Happy Face" Crater sur le site de la NASA.</a></div>
PIA02325: Have a Nice Spring! MOC Revisits "Happy Face" Crater

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