Ray from Gratteri Crater
Ray from Gratteri Crater
ESP_020922_1635  Science Theme: Impact Processes
Gratteri Crater, located about 150 kilometers to the southeast, ejected rocks that created millions of secondary craters over a region at least 500 kilometers wide.

Many of these secondary craters are concentrated in rays, or lines extending radially from Gratteri. Crater rays on the Moon are typically bright at visible wavelengths, but on Mars they are often best seen in the thermal infrared wavelengths, from temperature contrasts.

This image confirms that this ray contains many secondary craters--they are the small, sharp-rimmed craters. Since millions of secondary craters form at once, they all have the same age and same degree of modification over time.

Understanding the distribution of secondary craters provides information about impact processes, including escape of rocks that could become Martian meteorites on Earth.

Written by: Alfred McEwen  (23 February 2011)

This is a stereo pair with PSP_006510_1635.
Acquisition date
12 January 2011

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
260.8 km (162.1 miles)

Original image scale range
from 29.7 cm/pixel (with 1 x 1 binning) to 59.5 cm/pixel (with 2 x 2 binning)

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
50°, with the Sun about 40° above the horizon

Solar longitude
216.1°, Northern Autumn

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  358.9°
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   (764MB)

IRB color
map-projected   (385MB)

Black and white
map-projected  (371MB)
non-map           (253MB)

IRB color
map projected  (129MB)
non-map           (340MB)

Merged IRB
map projected  (240MB)

Merged RGB
map-projected  (232MB)

RGB color
non map           (330MB)
Map-projected, reduced-resolution
Full resolution JP2 download
Anaglyph 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’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.