Changes of a Happy Crater
Changes of a Happy Crater
ESP_067414_0945  Science Theme: Polar Geology
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.

Written by: Ross Beyer (narration: Tre Gibbs)  (21 January 2021)
Acquisition date
13 December 2020

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
246.6 km (153.3 miles)

Original image scale range
24.7 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
77°, with the Sun about 13° above the horizon

Solar longitude
330.6°, Northern Winter

For non-map projected images
North azimuth:  126°
Sub-solar azimuth:  49.8°
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   (362MB)

IRB color
map-projected   (225MB)

Black and white
map-projected  (165MB)
non-map           (176MB)

IRB color
map projected  (57MB)
non-map           (207MB)

Merged IRB
map projected  (87MB)

Merged RGB
map-projected  (79MB)

RGB color
non map           (178MB)
10K (TIFF)

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’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.