Edited Mars Reconnaissance Orbiter image of a candidate landing site for NASA's Mars 2020 rover mission, in Gusev Crater (the same crater where Spirit Landed in 2004).

Edited Mars Reconnaissance Orbiter image of a 144 meter circular feature in the south polar region of Mars.

Edited Mars Reconnaissance Orbiter image of a circular feature (not necessarily a crater) in the residual ice cap of the South Pole of Mars.

Edited Mars Reconnaissance Orbiter image of dust devil tracks in Brazos Basin.

Edited Mars Reconnaissance Orbiter image of the colors at the top of Coprates Chasma on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of part of Mawrth Vallis on Mars.

Edited MRO image of defrosting patterns on ridges in an area of Mars known (colloquially) as "Inca City."

Edited Mars Reconnaissance Orbiter image of a dune field in east Endeavour Crater, which is where Opportunity is currently operating. Color variant.

Edited Mars Reconnaissance Orbiter image of West Ladon Valles on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of ejecta from sublimating carbon dioxide in the Martian south polar area.

Edited Mars Reconnaissance Orbiter image of a crater in the south polar region of Mars that appears to be smiling for the camera. Color/processing variant.

Image source: www.uahirise.org/hipod/ESP_067414_0945

Original caption: We’ve monitored the so-called Happy Face Crater in the south polar region of Mars for almost a decade. Two images that we took, one in 2011 and the other in 2020, at roughly the same season, show color variations that are due to different amounts of bright frost over darker red ground.

The “blobby” features in the polar cap are due to the sun sublimating away the carbon dioxide into these round patterns. You can see how nine years of this thermal erosion have made the “mouth” of the face larger. The “nose” consisted of a two circular depressions in 2011, and in 2020, those two depressions have grown larger and merged.

Measuring these changes throughout the Martian year help scientists understand the annual deposition and removal of polar frost, and monitoring these sites over long periods helps us understand longer term climate trends on the Red Planet.

ID: ESP_067414_0945

date: 13 December 2020

altitude: 247 km

NASA/JPL/UArizona

uahirise.org/hipod/ESP_067414_0945

Edited Mars Reconnaissance Orbiter image of sand dunes in Nili Patera on Mars.

Edited Mars Reconnaissance Orbiter image of a candidate impact site for a small asteroid on Mars (where "candidate" means "virtually certain"). Color variant.

Edited Mars Reconnaissance Orbiter of pitted terrain in the Ultima Lingula region.

Edited Mars Reconnaissance Orbiter image of the central uplift of a crater near Pettit Crater. Color variant.

Edited Mars Reconnaissance Orbiter PR image of fractured mounds in Elysium Planitia.

Edited Mars Reconnaissance Orbiter image of sand dunes on Mars. Color variant.

Edited Mars Reconnaissance Orbiter image of parts of Aram Chaos on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of rugged Martian terrain.

Edited Mars Reconnaissance Orbiter image of pits and sand dunes in Hale Crater. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of a pit on a crater wall on Mars.

Edited Mars Reconnaissance Orbiter image of a lava dike on Mars.

Edited Mars Reconnaissance Orbiter image of frost on sand dunes.

Edited Mars Reconnaissance Orbiter image of an ancient lava flow in Alba Fossae on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of sand dunes in Stokes Crater.

Edited Mars Reconnaissance Orbiter image of the west flank of Chasma Boreale with barchan and linear sand dunes. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of layered terrain on Mars. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of a crater in the south polar region of Mars that appears to be smiling for the camera. Color/processing variant.

Image source: www.uahirise.org/hipod/ESP_067414_0945

Original caption: We’ve monitored the so-called Happy Face Crater in the south polar region of Mars for almost a decade. Two images that we took, one in 2011 and the other in 2020, at roughly the same season, show color variations that are due to different amounts of bright frost over darker red ground.

The “blobby” features in the polar cap are due to the sun sublimating away the carbon dioxide into these round patterns. You can see how nine years of this thermal erosion have made the “mouth” of the face larger. The “nose” consisted of a two circular depressions in 2011, and in 2020, those two depressions have grown larger and merged.

Measuring these changes throughout the Martian year help scientists understand the annual deposition and removal of polar frost, and monitoring these sites over long periods helps us understand longer term climate trends on the Red Planet.

ID: ESP_067414_0945

date: 13 December 2020

altitude: 247 km

NASA/JPL/UArizona

uahirise.org/hipod/ESP_067414_0945

Edited Mars Reconnaissance Orbiter image of a crater on Mars with a dune field in its middle situated such that it resembles a huge cat eye staring back at MRO.

Edited Mars Reconnaissance Orbiter image of chaotic terrain on the floor of Candor Chasma on Mars. Processing variant.

Edited Mars Reconnaissance Orbiter image of alluvial fan stratigraphy in Saheki Crater.

Edited Mars Reconnaissance Orbiter image of "dune convoys in West Olympia Undae. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of part of Candor Chasma showing swirly rock and sand layers. Grayscale PR version.

Edited Mars Reconnaissance Orbiter image of Libya Montes, a possible landing site for a future probe.

Original caption: Proposed Site for Future Exploration in Libya Montes

The Libya Montes are a highland terrain on Mars up-lifted by the giant impact that created the Isidis basin to the north.

NASA/JPL/University of Arizona (273 km above the surface, less than 5 km top to bottom and north is to the right.)

Source: www.uahirise.org/ESP_022970_1835

Edited Mars Reconnaissance Orbiter image of parts of Aram Chaos on Mars.

Edited Mars Reconnaissance Orbiter image of scalloped terrain in Utopia Planitia on Mars.

Edited Mars Reconnaissance Orbiter image of a heavily cratered mesa with crater ejecta. Color/processing variant.

Edited Mars Reconnaissance Orbiter image of a sand dune field over layers of bedrock on Mars.

Edited Mars Reconnaissance Orbiter image of mesas on a flat-looking Martian plain.

Edited Mars Reconnaissance Orbiter image of the central uplift of an impact crater.

Edited Mars Reconnaissance Orbiter image of fading dust devil tracks on Mars, being used to determine the rate of dustiness, which is, apparently, quite high.

Edited Mars Reconnaissance Orbiter image of a possible landing site for ESA's NASA's InSight mission.

This image shows a portion of a lobate debris apron along the bottom of a hill in the Promethei Terra region of Mars. This region contains many such mesas surrounded by lobate debris aprons that are thought to be ice-rich. These aprons have been interpreted as a variety of possible features including rock glaciers, ice-rich mass movements, or debris-covered glacial flows. Recent radar data have shown them to be composed of nearly 100% pure ice. Parallel grooves and ridges indicate the direction of flow.

Edited Mars Reconnaissance Orbiter image of the floor of Palos Crater.

Edited Mars Reconnaissance Orbiter image of the steep scarp on the edge of the north polar ice cap. Grayscale close-up. Color/processing variant.

Image source: www.uahirise.org/ESP_054663_2650

Original caption: HiRISE has been re-imaging regions first photographed in 2006 through 2007, six Mars years ago. This long baseline allows us to see large, rare changes as well as many smaller changes.

One of the most actively changing areas on Mars are the steep edges of the North Polar layered deposits. This image shows many new ice blocks compared to an earlier image in December 2006. An animation shows one example, where a section of ice cliff collapsed. The older image (acquired in bin-2 mode) is not as sharp as the newer one.

Written by: Alfred McEwen (audio: Tre Gibbs) (25 June 2018)

Edited Mars Reconnaissance Orbiter image of seasonal frost on dark sand dunes. Processing variant.

Edited Mars Reconnaissance Orbiter image of inverted polygonal terrain in Schoner Crater on Mars. Processing variant.

Heavily processed image of Assam. I used a Mars Reconnaissance Orbiter image of Danielson Crater as the seed image.

Edited Mars Reconnaissance Orbiter image of the floor of Coprates Chasma on Mars. Color/processing variant.