Mars Global Surveyor - Mission Results

Mission Results

After analyzing hundreds of high-resolution pictures of the Martian surface taken by the orbiting Mars Surveyor spacecraft, a team of researchers found that weathering and winds on the planet create landforms, especially sand dunes, remarkably similar to those in some deserts on Earth.

Results from the Mars Global Surveyor primary mission (1996–2001) were published in the Journal of Geophysical Research by M. Malin and K. Edgett. Some of these discoveries are:

• The planet was found to have a layered crust to depths of 10 km or more. To produce the layers, large amounts of material had to be weathered, transported and deposited.

• Layers in an old crater in Arabia, as seen by Mars Global Surveyor (MGS). Layers may form from volcanoes, the wind, or by deposition under water. The craters on the left are pedestal craters.

• Layers in crater found within the Schiaparelli crater basin as seen by Mars Global Surveyor. Image from the Sinus Sabaeus quadrangle.

• Layers in Monument Valley. These are accepted as being formed, at least in part, by water deposition. Since Mars contains similar layers, water remains as a major cause of layering on Mars.

• Buttes and layers in Aeolis quadrangle, as seen by Mars Global Surveyor.

• The northern hemisphere is probably just as cratered as the southern hemisphere, but the craters are mostly buried.

• Many features, like impact craters, were buried, then recently exhumed.

• Crater that was buried in another age and is now being exposed by erosion, as seen by the Mars Global Surveyor. Image is located in the Noachis quadrangle.

• Lava flows were once covered over, now these platy flows are being exposed.

• Crater was buried, now it is being exhumed by erosion. Image located in Ismenius Lacus quadrangle.

• The northern hemisphere appears smooth, but the craters are covered over. Here, a group of craters are patially exposed. Image located in Cebrenia quadrangle.

• Hundreds of gullies were discovered that were formed from liquid water, possible in recent times.

• Group of gullies on north wall of crater that lies west of the crater Newton (41.3047 degrees south latitude, 192.89 east longitide). Image taken with Mars Global Surveyor. Image is located in the Phaethontis quadrangle.

• Gullies in a crater in Eridania quadrangle, north of the large crater Kepler. Also, features that may be remains of old glaciers are present. One, to the right, has the shape of a tongue.

• Gullies on one wall of Kaiser Crater. Gullies usually are found in only one wall of a crater.

• Full color image of gullies on wall of Gorgonum Chaos. Image is located in the Phaethontis quadrangle.

• Large areas of Mars are covered by a mantle that coats all, but the very steepest slopes. The mantle is sometimes smooth, sometimes pitted. Some believe the pits are due to the escape of water through sublimation (ice changing directly to a vapor) of buried ice.

• Close up image of Phaethontis surface taken with Mars Global Surveyor. Pits are thought to be caused by buried ice turning into a gas.

• The mantle drapes most of the area. Note the absence of boulders on the cliff face. An area that shows the edges of the mantle is circled. Image located in Ismenius Lacus quadrangle.

• Mantle material, as seen by MGS.

• Steep Cliff in Ismenius Lacus quadrangle with smooth mantle covering its face.

• Some areas are covered by hematite-rich material. The hematite could have been put in place by liquid water in the past.

• Dark streaks were found to be caused by giant dust devils. Dust Devil Tracks were observed to frequently change; some changed in just one month.

• Pattern of large and small tracks made by giant dust devils as seen by Mars Global Surveyor. Image is located in Eridania quadrangle.

• Kepler (Martian crater) showing dust devil tracks, as seen by Mars Global Surveyor. Kepler is a large crater in the Eridania quadrangle.

• Dust Devil, as seen by MGS.

• Dust Devil in action showing shadow to the right. Image located in Cebrenia quadrangle.

• The south pole's residual cap was observed to look like Swiss cheese. The holes are generally a few meters deep. The holes get bigger each year, so Mars may be warming.

• Changes in South Pole from 1999 to 2001, as seen by Mars Global Surveyor. Notice how swiss-cheese type holes have grown in the two years.

• Swiss Cheese Terrain, as seen by MGS. Largest mesa in image is 4 meters high.

• Layers in Swiss Cheese Terrain. There is a bright upper layer and a darker lower layer.

• Close-up view of Swiss Cheese Terrain. Polygonal pattern was probably formed by shallow troughs.

• The Thermal Emission Spectrometer found that just about all of the surface of Mars is covered with volcanic rock.

• Ceraunius Tholus, one of many volcanoes found on Mars.

• Lava flows in the Tharsis quadrangle.

• Image shows both young and old lava flows from the base of Olympus Mons. The flat plain is the younger flow. The older flow has channels with levees along their edges. The presence of levees is quite common in many lava flows.

• Small Volcano in Phoenicis Lacus quadrangle. Image is 1.9 miles (3.1 km) wide.

• Hundreds of house-sized boulders were found in some areas. This indicates that some materials are strong enough to hold together, even when moving downslope. Most of the boulders appeared in volcanic regions so they were probably from weathered from lava flows.

• House-sized boulders are scattered throughout this image.

• These boulders are near Ascraeus Mons, a Martian volcano. Volcanoes on Mars probably form hard boulders made up of basalt that is resistant to erosion in the current environment of Mars.

• Thousands of dark slope streaks were observed. Most scientists believe they result from the avalanching of dust. However, some researchers think that water may be involved.

• Many streaks underwent changes during the many years that MGS functioned.

• Tikonravev Crater Floor, as seen by Mars Global Surveyor. Click on image to see dark slope streaks and layers. Tikonravev Crater is in the Arabia quadrangle.

• Dark streaks in Diacria quadrangle, as seen by Mars Global Surveyor.