On Frozen Ground
On Frozen Ground
ESP_066782_1110  Science Theme: Glacial/Periglacial Processes
The soil surface on Mars is believed to contain water ice, especially at higher latitudes. Similar to permafrost regions on Earth, this permanently frozen water remains geologically active.

With the changing seasons, alternate cooling and warming causes the ice-cemented soil to contract and expand. Under favorable conditions these forces generate cracks into the hard frozen ground releasing the stresses caused by contraction. Over years of cyclic cracking, a curious honeycomb-like polygonal pattern arises.

The presence of these widespread patterns on Mars present valuable clues as to the occurrence or absence of ice in the subsurface. This image shows a textbook example of regular, nearly hexagonal polygon networks. The geometry of the polygons reveals hints of how long the ice has been there and how deeply buried it may be.

Written by: Mike Mellon (narration: Tre Gibbs)  (17 December 2020)
Acquisition date
25 October 2020

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
247.8 km (154.0 miles)

Original image scale range
24.8 cm/pixel (with 1 x 1 binning) so objects ~74 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
56°, with the Sun about 34° above the horizon

Solar longitude
302.4°, Northern Winter

For non-map projected images
North azimuth:  99°
Sub-solar azimuth:  42.5°
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

Black and white
map-projected   (721MB)

IRB color
map-projected   (429MB)

Black and white
map-projected  (429MB)
non-map           (483MB)

IRB color
map projected  (216MB)
non-map           (380MB)

Merged IRB
map projected  (214MB)

Merged RGB
map-projected  (210MB)

RGB color
non map           (370MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL/University of Arizona

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.