Segment of a Crater Ray
Segment of a Crater Ray
PSP_007751_1640  Science Theme: Impact Processes
This image was planned to take a closer look at what appears to be a segment of a crater ray.

Relatively recent impacts form rays like those of Tycho Crater on the Moon. There, rays stand out because they are brighter than the surroundings, but on Mars they are best found from nighttime infrared images, sensitive to temperature variations, acquired by the THEMIS instrument on the Mars Odyssey spacecraft. The rays consist of thin layers of ejecta from both the primary (source) crater and the millions or even billions of small secondary craters. The crater ejecta and surge deposits churned up by the interacting ejecta get mixed and deposited together.

This ray segment is approximately 1000 kilometers away from the source crater (15 km diameter), located at 16.95 N, 141.73 E; see PSP_003611_1970). This source crater, which doesn’t yet have an official name, is now the largest known rayed crater on Mars.

There are more than half a million small craters seen in this one image, which covers less than 1 percent of the ray system. This image will be used to count the number of secondary craters and measure their sizes, to determine the size-frequency distribution. This work will help scientists to better understand impact processes, the origins of small craters, and the modification of landscapes.

Written by: Alfred  (30 April 2008)
Acquisition date
22 March 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
260.6 km (162.0 miles)

Original image scale range
26.2 cm/pixel (with 1 x 1 binning) so objects ~79 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

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

Solar longitude
48.4°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  41.6°
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   (1263MB)

IRB color
map-projected   (594MB)

Black and white
map-projected  (668MB)
non-map           (749MB)

IRB color
map projected  (237MB)
non-map           (583MB)

Merged IRB
map projected  (303MB)

Merged RGB
map-projected  (310MB)

RGB color
non map           (551MB)
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.