HiWish program

HiWish is a program created by NASA so that anyone can suggest a place for the HiRISE camera on the Mars Reconnaissance Orbiter to photograph. It was started in January 2010. In the first few months of the program 3000 people signed up to use HiRISE. The first images were released in April 2010. Over 12,000 suggestions were made by the public; suggestions were made for targets in each of the 30 quadrangles of Mars. Selected images released were used for three talks at the 16th Annual International Mars Society Convention. Below are some of the over 4,224 images that have been released from the HiWish program as of March 2016.

Glacial features

Some landscapes look just like glaciers moving out of mountain valleys on Earth. Some have a hollowed-out appearance, looking like a glacier after almost all the ice has disappeared. What is left are the moraines—the dirt and debris carried by the glacier. The center is hollowed out because the ice is mostly gone. These supposed alpine glaciers have been called glacier-like forms (GLF) or glacier-like flows (GLF). Glacier-like forms are a later and maybe more accurate term because we cannot be sure the structure is currently moving.

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Image:Wide view of glacier showing image field.JPG, Possible glacier flowing down a valley and spreading out on a plain. Rectangle shows a portion that is enlarged in the next image.
Image:Glacier close up with hirise.JPG, Enlargement of the area in the rectangle in the previous image. This area would be called a moraine in an alpine glacier on Earth.
Image:Hollows as seen by hirise under hiwish program.jpg, Well-developed hollows of concentric crater fill, as seen by HiRISE under the HiWish program.

44410 2195glacier.jpg, Glacier on a crater floor, as seen by HiRISE under HiWish program The cracks in the glacier may be crevasses. There is also a gully system on the crater wall.

ESP 045560 2230wideglacier.jpg, Glacier coming out of valley, as seen by HiRISE under HiWish program Location is rim of Moreux Crater. Location is Ismenius Lacus quadrangle.

ESP 047193 1440tongues.jpg, Wide view of tongue-shaped flows, as seen by HiRISE under the HiWish program
47193 1440tonguesclose.jpg, Close view of tongue-shaped flows, as seen by HiRISE under the HiWish program

Possible pingos

The radial and concentric cracks visible here are common when forces penetrate a brittle layer, such as a rock thrown through a glass window. These particular fractures were probably created by something emerging from below the brittle Martian surface. Ice may have accumulated under the surface in a lens shape; thus making these cracked mounds. Ice being less dense than rock, pushed upwards on the surface and generated these spider web-like patterns. A similar process creates similar sized mounds in arctic tundra on Earth. Such features are called "pingos," an Inuit word. Pingos would contain pure water ice; thus they could be sources of water for future colonists of Mars. Many features that look like the pingos on the Earth are found in Utopia Planitia (~35-50° N; ~80-115° E).

ESP 046359 1250-1pingosclosespecial.jpg, Possible pingos with scale, as seen by HiRISE under HiWish program
ESP 046359 1250-2pingoscale.jpg, Close view of possible pingo with scale, as seen by HiRISE under HiWish program

Ancient rivers and streams

There is great deal of evidence that water once flowed in river valleys on Mars. Pictures from orbit show winding valleys, branched valleys, and even meanders with oxbow lakes. Some are visible in the pictures below.

WikiESP 034082 1375channel.jpg, Channel on floor of Newton Crater, as seen by HiRISE under HiWish program.
ESP 037045 2235channel.jpg, Branched channel, as seen by HiRISE under HiWish program.
File:ESP 054919 1465channels.jpg, Channel, as seen by HiRISE under HiWish program
WikiESP 033729 1410stream.jpg, Branched channel, as seen by HiRISE under HiWish program.

WikiESP 039594 1365oxbow.jpg, Oxbow lake, as seen by HiRISE under HiWish program.

WikiESP 035449 2100stream.jpg, Valleys as seen by HiRISE under HiWish program

WikiESP 039997 2170channels.jpg, Channel in Arabia, as seen by HiRISE under HiWish program.

ESP 042924 2195channel.jpg, Channel system that travels through part of a crater, as seen by HiRISE under HiWish program
Image:ESP_025336channels.jpg, Channels, as seen by HiRISE under HiWish program. Stream appears to have eroded through a hill.
ESP 045779 1730meander.jpg, Channel showing an old oxbow and a cutoff, as seen by HiRISE under HiWish program. Location is Memnonia quadrangle.

File:ESP 057410 1445channelinvalley.jpg, Channel on floor of valley, as seen by HiRISE under HiWish program. Location is Eridania quadrangle.

45837 2245channel.jpg, Close view of channel in Ismenius Lacus quadrangle, as seen by HiRISE under HiWish program

45916 2205hanging.jpg, Channel with hanging valley in Ismenius Lacus quadrangle, as seen by HiRISE under HiWish program
ESP 048582 1845hangingvalleys.jpg, Hanging valleys in Aram Chaos, as seen by HiRISE under HiWish program

ESP 045864 2160channels.jpg, Wide view of channels in Ismenius Lacus quadrangle, as seen by HiRISE under HiWish program

Streamlined shapes

Streamlined shapes represent more evidence of past flowing water on Mars. Water shaped features into streamlined shapes.

ESP 045897 1645streamlined.jpg, Streamlined feature, as seen by HiRISE under HiWish program Location is Memnonia quadrangle.
ESP 050856 1445channels.jpg, Channel, as seen by HiRISE under HiWish program Streamlined shapes are indicated with arrows. Location is the Phaethontis quadrangle.

ESP 045860 2085streamlined.jpg, Wide view of streamlined shapes in Amenthes quadrangle, as seen by HiRISE under HiWish program
ESP 045860 2085streamlinedbottom.jpg, Close view of streamlined shapes, as seen by HiRISE under HiWish program Arrow indicates the direction of past flowing water.
ESP 045860 2085streamlinedmiddle.jpg, Close view of streamlined shapes, as seen by HiRISE under HiWish program
ESP 045860 2085streamlinedtop.jpg, Close view of streamlined shapes, as seen by HiRISE under HiWish program
ESP 045860 2085streamlineduppertop.jpg, Close view of streamlined shapes, as seen by HiRISE under HiWish program
45860 2085close.jpg, Close view of streamlined shape, as seen by HiRISE under HiWish program
ESP 052677 2075streamlined.jpg, Streamlined shapes, as seen by HiRISE under HiWish program Location is the Elysium quadrangle.

New Crater

29565 2075newcratercomposite.jpg, HiRISE images showing discovery of a new crater with HiWish program
Image:29564_2075newcraterclose.jpg, New crater, as seen by HiRISE under HiWish program. The new crater indicated with the white arrow is about 10 yards across and was probably created by the collision with an object the size of a large watermelon. This crater did not appear in earlier images of the same region.

Sand dunes

Many locations on Mars have sand dunes. The dunes are covered by a seasonal carbon dioxide frost that forms in early autumn and remains until late spring. Many martian dunes strongly resemble terrestrial dunes but images acquired by the High-Resolution Imaging Science Experiment on the Mars Reconnaissance Orbiter have shown that martian dunes in the north polar region are subject to modification via grainflow triggered by seasonal sublimation, a process not seen on Earth. Many dunes are black because they are derived from the dark volcanic rock basalt. Extraterrestrial sand seas such as those found on Mars are referred to as "undae" from the Latin for waves.

34745 34694combdunes.jpg, Dunes in two craters, as seen by HiRISE under the HiWish program.
Image:ESP 034956 1745dunescraters.jpg, Dunes among craters, as seen by HiRISE under HiWish program. Some of these are barchans.
ESP 023561dunes.jpg, Dunes on a crater floor, as seen by HiRISE under HiWish program. Most of these are barchans. Box shows location of next image. Location is the Eridania quadrangle.
ESP 023561dunesclose.jpg, Dunes on a crater floor, as seen by HiRISE under HiWish program. Most of these are barchans. Note: this is an enlargement of the center of the previous image.
Esp 037367 1340bdunes.jpg, Dunes, as seen by HiRISE under HiWish program. Location is Eridania quadrangle.

ESP 043821 2555dryice.jpg, Defrosting dunes and ice in troughs of polygons, as seen by HiRISE under HiWish program
ESP 043821 2555dryicecolor.jpg, Color view of defrosting dunes and ice in troughs of polygons, as seen by HiRISE under HiWish program
43821 2555defrostingdune.jpg, Defrosting surface, as seen by HiRISE under HiWish program Frost is disappearing in patches from a dune. The trough boundaries around the polygon shapes still contain frost; hence they are white. Note: the north side (side near top) has not defrosted because the sun is coming from the other side.

ESP 044861 2225dunes.jpg, Wide view of dunes in Moreux Crater, as seen by HiRISE under HiWish program
ESP 045822 1680dunes.jpg, Dunes in Mare Tyrrhenum quadrangle, as seen by HiRISE under HiWish program
45822 1680dunesclose.jpg, Close view of dunes in Mare Tyrrhenum quadrangle, as seen by HiRISE under HiWish program
45822 1680color.jpg, Close, color view of dunes in Mare Tyrrhenum quadrangle, as seen by HiRISE under HiWish program Ripples are visible on dune surface.
File:55097 1455dunescolor.jpg, Close, color view of dome sand dunes, as seen by HiRISE under HiWish program

Landing site

Some of the targets suggested became possible sites for a Rover Mission in 2020. The targets were in Firsoff (crater) and Holden Crater. These locations were picked as two of 26 locations considered for a mission that will look for signs of life and gather samples for a later return to Earth.

ESP 039404 1820landingsitetop.jpg, Layers in Firsoff Crater, as seen by HiRISE under HiWish program Note: this image field can be found in the previous image of the layers in Firsoff Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter).
ESP 039404 1820landingsiteclose.jpg, Close-up of layers in Firsoff Crater, as seen by HiRISE Note: this is an enlargement of the previous image of Firsoff Crater.

Wikiesp 039404 1820landingdustfield.jpg, Layers in Firsoff crater with a box showing the size of a football field Picture taken by HiRISE under HiWish program.
Wikiesp 039404 1820landingfir.jpg, Layers and faults in Firsoff Crater, as seen by HiRISE under HiWish program. Arrows show one large fault, but there are other smaller ones in the picture.

ESP 026126 1530delta.jpg, Part of delta in Holden Crater, as seen by HiRISE under HiWish program Holden crater is a possible landing site for a Mars Rover scheduled for 2020.
26126 1530deltalayers.jpg, Close view of previous image showing layers, as seen by HiRISE under HiWish program and enlarged with HiView

Landscape features

Image:Troughs in Elysium Planitia.JPG, Troughs to the East of Albor Tholus, as seen by HiRISE under the HiWish program.
Image:Troughs showing blue in Elysium Planitia.JPG, Portion of a trough (Fossae) in Elysium Planitia, as seen by HiRISE under the HiWish program. Blue indicates possible seasonal frost.
ESP 043963 1550landslide.jpg, Landslide in a crater, as seen by HiRISE under HiWish program Image from Iapygia quadrangle.

ESP 045016 2080mesas.jpg, Wide view of Buttes and Mesas, as seen by HiRISE under HiWish program Location is Elysium quadrangle.

45016 2080mesas2.jpg, Buttes and mesas, as seen by HiRISE under HiWish program Note: this is an enlargement of the previous image.
45016 2080mesas.jpg, Mesas, as seen by HiRISE under HiWish program Note: this is an enlargement of a previous image.

Dark slope streaks

Image:ESP_036956_1895layers.jpg, Layers and dark slope streaks, as seen by HiRISE under HiWish program
Esp 036851 1995mesastreaks.jpg, Dark slope streaks on mesa, as seen by HiRISE under HiWish program Location is Amazonis quadrangle.

Image:25609layersstreak.jpg, Close-up of some layers under cap rock of a pedestal crater and a dark slope streak, as seen by HiRISE under HiWish program.

Image:Streaks22919.jpg, Dark slope streaks and layers near a pedestal crater, as seen by HiRISE under the HiWish program. Arrows show the small starting points for the streaks.

44802streaks.jpg, Dark slope streaks on mound in Lycus Sulci in Diacria quadrangle, as seen by HiRISE under HiWish program
ESP 045435 2055troughlayers.jpg, Layers in trough and dark slope streaks, as seen by HiRISE under HiWish program Location is Amazonis quadrangle.

Recurrent slope lineae

Recurrent slope lineae are small dark streaks on slopes that elongate in warm seasons. They may be evidence of liquid water. However, there remains debate about whether water or much water is needed.

ESP 049955 1665rslbox.jpg, Wide view of part of Valles Marineris, as seen by HiRISE under HiWish program Box shows location of recurrent slope lineae that are enlarged in next image.
49955 1665rslcolorarrows.jpg, Close, color view of recurrent slope lineae, as seen by HiRISE under HiWish program Arrows point to some of the recurrent slope lineae

Layers

Many places on Mars show rocks arranged in layers. Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers. Layers can be hardened by the action of groundwater. ,

Image:ESP 039673 1705layeredbuttes.jpg, Layers exposed at the base of a group of buttes in Mangala Valles in Memnonia quadrangle, as seen by HiRISE under HiWish program. Arrows point to boulders sitting in pits. The pits may have formed by winds, heat from the boulders melting ground ice, or some other process.
Image:ESP 025558buttes.jpg, Buttes, as seen by HiRISE under HiWish program. Buttes have layered rocks with a hard resistant cap rock on the top which protects the underlying rocks from erosion.
Image:Wikiesp 035896 1845crommelinbutte.jpg, Butte in Crommelin Crater, as seen by HiRISE under HiWish program. Location is Oxia Palus quadrangle.
Image:Wikiesp 035896 1845crommelinhollows.jpg, Layers in Crommelin Crater, as seen by HiRISE under HiWish program. Location is Oxia Palus quadrangle.

File:60331 1880mound.jpg, Layered mound on floor of Danielson Crater, as seen by HiRISE under HiWish program

File:60331 1880layerscolortop2.jpg, Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program

File:60331 1880layersclosecolor4boulders.jpg, Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program Boulders are visible in the image.

File:60331 1880layerscolorfaults.jpg, Close, color view of layers and dark dust on floor of Danielson Crater, as seen by HiRISE under HiWish program Faults are indicated with arrows.

File:60331 1880widefault.jpg, Close view of layers on floor of Danielson Crater, as seen by HiRISE under HiWish program Some faults are visible in image.

Image:ESP_024807whitebutte.jpg, Light toned butte on floor of crater, as seen by HiRISE under HiWish program. Arrows show outcrops of light toned material. Light toned material is probably sulfate-rich and similar to material examined by Spirit Rover, and it once probably covered the whole floor. Other images below show enlargements of the butte. Location is Margaritifer Sinus quadrangle.
24807whitebuttei.jpg, Enlargement of white butte, as seen by HiRISE under HiWish program Box shows size of a football field.
24807 1755whitebuttezoomed.jpg, Closer view towards top of white butte, as seen by HiRISE under HiWish program Box shows size of a football field.
24807 1755whitebuttetop.jpg, Top of white butte, as seen by HiRISE under HiWish program Box shows size of a football field.

Image:ESP 036510 1735layers.jpg, Layered terrain in Aeolis quadrangle, as seen by HiRISE under HiWish program.
ESP 045029 1785moundlayers.jpg, Wide view of layered terrain, as seen by HiRISE under HiWish program Location is northeast of Gale Crater in Aeolis quadrangle.
45029 1785layerswide.jpg, Close view of mound with layers, as seen by HiRISE under HiWish program Note: this is an enlargement from the previous image.
45029 1785layersclose.jpg, Close view of mound with layers, as seen by HiRISE under HiWish program Note: this is an enlargement from a previous image.

Image:ESP_028353layers.jpg, Layers in Arabia, as seen by HiRISE under HiWish program.
Image:ESP 044507 1880layersdanielson.jpg, Wide view of part of Danielson Crater, as seen by HiRISE under HiWish program
Image:44507 1880longlayers.jpg, Enlargement of previous image of Danielson Crater, as seen by HiRISE under HiWish program The box represents the size of a football field.
Image:44507 1880bouldersclose.jpg, Close-up of layers in Danielson Crater, as seen by HiRISE under HiWish program—boulders are visible, as well as dark sand

43376 1710layersclose.jpg, Close-up of layers in trough south of Ius Chasma, as seen by HiRISE under HiWish program
042055 1580layersclose.jpg, Close-up of layers in Lotto Crater, as seen by HiRISE under HiWish program

ESP 043824 2180layers.jpg, Layers, as seen by HiRISE under HiWish program Location is Tempe Terra
43824 2160layers.jpg, Layers, as seen by HiRISE under HiWish program Location is Tempe Terra Note: this is an enlargement of the previous image.


46234 1845layersclose.jpg, Close view of layers, as seen by HiRISE under HiWish program At least one layer is light-toned which may indicated hydrated minerals.
46234 1845layerstop.jpg, Close view of layers, as seen by HiRISE under HiWish program

This group of layers that are found in a crater all come from the Arabia quadrangle.

ESP 047421 1890nicelayers.jpg, Wide view of layers in crater, as seen by HiRISE under HiWish program parts of this image are enlarged in other images that follow.
47421 1890bigbutte.jpg, Close view of layers, as seen by HiRISE under HiWish program Box shows the size of a football field.
47421 1890layeredterrain.jpg, Close view of layers, as seen by HiRISE under HiWish program Box shows the size of a football field.

47421 1890layers5buttes.jpg, Close view of layers, as seen by HiRISE under HiWish program Box shows the size of a football field.

47421 1890layersbutte.jpg, Close view of layers, as seen by HiRISE under HiWish program

47421 1890layersbuttesclose.jpg, Close view of layers, as seen by HiRISE under HiWish program

47421 1890layerssuperclose.jpg, Close view of layers, as seen by HiRISE under HiWish program
47421 1890pointed butte.jpg, Close view of layers, as seen by HiRISE under HiWish program
47421 1890layersdhadow.jpg, Close view of layers, as seen by HiRISE under HiWish program

This next group of layered terrain comes from the Louros Valles in the Coprates quadrangle.

ESP 048980 1725layers.jpg, Wide view of layers in Louros Valles, as seen by HiRISE under HiWish program
48980 1725layersclose2.jpg, Close view of layers in Louros Valles, as seen by HiRISE under HiWish program Note this is an enlargement of a previous image.

48980 1725layers.jpg, Close view of layers in Louros Valles, as seen by HiRISE under HiWish program Note this is an enlargement of a previous image.

48980 1725layersclose.jpg, Close view of layers in Louros Valles, as seen by HiRISE under HiWish program Note this is an enlargement of a previous image.
ESP 048980 1725layersclosecolor.jpg, Close view of layers in Louros Valles, as seen by HiRISE under HiWish program Note this is an enlargement of a previous image.

Layers in Ice Cap

ESP 052405 2595icelayers.jpg, Layers in northern ice cap with an angular unconformity, as seen by HiRISE under HiWish program

52405 2595icelayers.jpg, Close view of layers in northern ice cap, as seen by HiRISE under HiWish program Arrows point to an angular unconformity.

ESP 052405 2595icelayersclosecolor.jpg, Close, color view of layers in northern ice cap, as seen by HiRISE under HiWish program

File:ESP 054515 2595icecaplayers.jpg, Layers exposed in northern ice cap, as seen by HiRISE under HiWish program
File:ESP 054515 2595icecaplayerspartial.jpg, Close view of layers exposed in northern ice cap, as seen by HiRISE under HiWish program

Gullies

Martian gullies are small, incised networks of narrow channels and their associated downslope sediment deposits, found on the planet of Mars. They are named for their resemblance to terrestrial gullies. First discovered on images from Mars Global Surveyor, they occur on steep slopes, especially on the walls of craters. Usually, each gully has a dendritic ''alcove'' at its head, a fan-shaped ''apron'' at its base, and a single thread of incised ''channel'' linking the two, giving the whole gully an hourglass shape. They are believed to be relatively young because they have few, if any craters.
On the basis of their form, aspects, positions, and location amongst and apparent interaction with features thought to be rich in water ice, many researchers believed that the processes carving the gullies involve liquid water. However, this remains a topic of active research. ,

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ESP 039621 1315aprons.jpg, Close-up of gully aprons showing they are free of craters; hence very young. Location is Phaethontis quadrangle. Picture was taken by HiRISE under HiWish program.

ESP 037506 2285gullychannels.jpg, Gullies on wall of crater, as seen by HiRISE under HiWish program Location is the Mare Acidalium quadrangle.
ESP 037506 2285gullychannelsclose.jpg, Close-up of gully channels, as seen by HiRISE under HiWish program. This image shows many streamlined forms and some benches along a channel. These features suggest formation by running water. Benches are usually formed when the water level goes down a bit and stays at that level for a time. Picture was taken with HiRISE under HiWish program. Location is the Mare Acidalium quadrangle. Note this is an enlargement of a previous image.

ESP 039753 1385gulliespits.jpg, Gullies in crater in Phaethontis quadrangle, as seen by HiRISE under HiWish program

ESP 044707 2285gullies.jpg, Gullies along mesa wall in North Tempe Terra, as seen by HiRISE under HiWish program
44707 2285apron.jpg, Close view of gully apron, as seen by HiRISE under HiWish program Note this is an enlargement of the previous image.
44707 2285alcove.jpg, Close view of gully alcove, as seen by HiRISE under HiWish program Note this is an enlargement of a previous image.


ESP 047395 1415gulliesridges.jpg, Gullies in crater, as seen by HiRISE under HiWish program

47395 1415gullycurvedchannels.jpg, Close view of gullies from previous image The channels are quite curved. Because channels of gullies often form curves, it was thought that they were made by flowing water. Today, it is thought that they could be produced with chunks of dry ice. The image is from HiRISE under HiWish program.

Latitude dependent mantle

Much of the Martian surface is covered with a thick ice-rich, mantle layer that has fallen from the sky a number of times in the past. In some places a number of layers are visible in the mantle.

Esp 037167 1445mantle.jpg, Surface showing appearance with and without mantle covering, as seen by HiRISE, under the HiWish program. Location is Terra Sirenum in Phaethontis quadrangle.
Image:2509mantlelayers.jpg, Mantle layers, as seen by HiRISE under HiWish program. Location is Eridania quadrangle
Image:24589mantle.jpg, Close up view of mantle, as seen by HiRISE under the HiWish program. Mantle may be composed of ice and dust that fell from the sky during past climatic conditions. Location is Cebrenia quadrangle.
45085 2205mantlethickness.jpg, Close view of mantle, as seen by HiRISE under HiWish program Arrows show craters along edge which highlight the thickness of mantle. Location is Ismenius Lacus quadrangle.

45917 2220gulliesmantle.jpg, Close view that displays the thickness of the mantle, as seen by HiRISE under HiWish program Location is Ismenius Lacus quadrangle.

ESP 050456 2250mantle.jpg, Wide view of surface with spots displaying mantle, as seen by HiRISE under HiWish program Location is the Arcadia quadrangle.

50456 2250mantle2.jpg, Close view of mantle, as seen by HiRISE under HiWish program

50456 2250mantle3.jpg, Close view of mantle, as seen by HiRISE under HiWish program

It fell as snow and ice-coated dust. There is good evidence that this mantle is ice-rich. The shapes of the polygons common on many surfaces suggest ice-rich soil. High levels of hydrogen (probably from water) have been found with Mars Odyssey. Thermal measurements from orbit suggest ice. The Phoenix (spacecraft) discovered water ice with made direct observations since it landed in a field of polygons.Bright Chunks at ''Phoenix'' Lander's Mars Site Must Have Been Ice
– Official NASA press release (19.06.2008) In fact, its landing rockets exposed pure ice. Theory had predicted that ice would be found under a few cm of soil. This mantle layer is called "latitude dependent mantle" because its occurrence is related to the latitude. It is this mantle that cracks and then forms polygonal ground. This cracking of ice-rich ground is predicted based on physical processes.

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Polygonal patterned ground

Polygonal, patterned ground is quite common in some regions of Mars. It is commonly believed to be caused by the sublimation of ice from the ground. Sublimation is the direct change of solid ice to a gas. This is similar to what happens to dry ice on the Earth. Places on Mars that display polygonal ground may indicate where future colonists can find water ice. Patterned ground forms in a mantle layer, called latitude dependent mantle, that fell from the sky when the climate was different.

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File:56148 1145polygonswide.jpg, Wide view of crater containing polygons with frost in the low parts, as seen by HiRISE under the HiWish program
File:56148 1145polygonsclose.jpg, Closer view of polygons with frost in the low parts, as seen by HiRISE under the HiWish program
File:56148 1145polygonsveryclose.jpg, Still closer view of polygons, as seen by HiRISE under the HiWish program
File:56148 1145polygonsveryclosecircles.jpg, Close view of polygons with frost in the low parts, as seen by HiRISE under the HiWish program Circular shapes are also visible.

44042 2240highcenterpolygons.jpg, High center polygons, shown with arrows, as seen by HiRISE under HiWish program. Location is Casius quadrangle. Image enlarged with HiView.
44042 2240scallops.jpg, Scalloped terrain labeled with both low center polygons and high center polygons, as seen by HiRISE under HiWish program Location is Casius quadrangle. Image enlarged with HiView.
44042 2240highlowcenters.jpg, High and low center polygons, as seen by HiRISE under HiWish program Location is Casius quadrangle. Image enlarged with HiView.
43899 2265highcenterpolygonsclose.jpg, Close-up of high center polygons seen by HiRISE under HiWish program Troughs between polygons are easily visible in this view. Location is Ismenius Lacus quadrangle.
44042 2240lowcenter.jpg, Low center polygons, as seen by HiRISE under HiWish program Location is Casius quadrangle. Image enlarged with HiView. Location is Casius quadrangle.

45070 1440glacialsnout.jpg, Close view of snout of glacier, as seen by HiRISE under the HiWish program High center polygons are visible. Box shows size of football field.
45070 1440polygonscloseshadows.jpg, Close view of high center polygons near glacier, as seen by HiRISE under the HiWish program Box shows size of football field.
45070 1440polygonshadows.jpg, Close view of high center polygons near glacier, as seen by HiRISE under the HiWish program

ESP 045299 1545channelswide.jpg, Wide view of a group of channels, as seen by HiRISE under HiWish project Some parts of the surface show patterned ground when enlarged.
45299 1545patternedground.jpg, Patterned ground, as seen by HiRISE under HiWish program This is a close up from previous image.

45299 1545ridges.jpg, Ridges, as seen by HiRISE under HiWish program This is a close up from a previous image.

ESP 045299 1545mediumclose.jpg, Color view of surface in a previous image, as seen by HiRISE under HiWish program

ESP 045299 1545coloredclose.jpg, Color image of patterned ground, enlarged from a previous image, as seen by HiRISE under HiWish program

Complex polygonal patterned ground

ESP 049660 1200polygons.jpg, Wide view of polygons, as seen by HiRISE under HiWish program Parts of this image are enlarged in following images. The location is the Noachis quadrangle

49660 1200polygonswide.jpg, Polygons, as seen by HiRISE under HiWish program

49660 1200polygonsrockscraters.jpg, Close view of polygons, as seen by HiRISE under HiWish program Arrow point to boulders that sit inside of small craters.

49660 1200polygonspits.jpg, Close view of polygons, as seen by HiRISE under HiWish program

49660 1200polygonsrockscratersclose.jpg, Close view of polygons, as seen by HiRISE under HiWish program

Exposed Ice Sheets

HiRISE images taken under the HiWish program found triangular shaped depressions in Milankovic Crater that researchers found contain vast amounts of ice that are found under only 1–2 meters of soil.
These depressions contain water ice in the straight wall that faces the pole, according to the study published in the journal Science. Eight sites were found with Milankovic Crater being the only one in the northern hemisphere. Research was conducted with instruments on board the Mars Reconnaissance Orbiter (MRO).