Seasonal Flows in Palikir Crater
NASA/JPL/University of Arizona
Seasonal Flows in Palikir Crater
ESP_031102_1380  Science Theme: Mass Wasting Processes
German  Icelandic  Italian  Spanish  Turkish 


720p (MP4)
Listen to the text


800  1024
1152  1280
1440  1600
1920  2048
2560  2880


PDF, 11 x 17 in


Seasonal flows on warm Martian slopes may be caused by the flow of salty water on Mars, active today when the surface is warm (above the freezing point of the solution).

Palikir Crater, which sits inside the much large Newton crater, contains thousands of individual flows called "Recurring Slope Linea", or RSL. In the Southern middle latitudes, RSL form and grow every summer in certain places, fading in late summer and fall.

A closeup view shows a comparison of RSL from one Mars year ago to a very recent image, over a small piece of Palikir Crater's steep northwest-facing slopes. The new image shows RSL are slightly more extensive and longer than at nearly the same time of year a Mars year ago.

The older image was acquired with the MRO spacecraft pointed 6 degrees to the west of nadir (or pointing straight down), whereas for the new image MRO was pointed 17 degrees to the east of nadir. As a result, we are seeing the steeply-sloping surface from different angles, exaggerating the appearance of longer RSL in the new image, but if you carefully compare the flows to the topography, you can see that they really are more numerous and some are longer this year compared to the past Martian summer, just about 2 days later in the year.

The RSL are remarkably repeatable from year to year in this location, with differences perhaps related to the weather--mainly due to variations in dust content of the air.

Written by: Alfred McEwen (audio by Tre Gibbs)  (15 May 2013)
twitter  •  facebook  •  google+  •  tumblr
Acquisition date
15 March 2013

Local Mars time:

Latitude (centered)

Longitude (East)

Range to target site
265.9 km (166.2 miles)

Original image scale range
26.6 cm/pixel (with 1 x 1 binning) so objects ~80 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle:

Phase angle:

Solar incidence angle
39°, with the Sun about 51° above the horizon

Solar longitude
282.9°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  19.9°
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   (471MB)

IRB color
map-projected   (267MB)

Black and white
map-projected  (207MB)
non-map           (264MB)

IRB color
map projected  (68MB)
non-map           (231MB)

Merged IRB
map projected  (120MB)

Merged RGB
map-projected  (116MB)

RGB color
non map           (234MB)
DTM details page

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.