Double Layer Ejecta in an Arabia Region Crater
Double Layer Ejecta in an Arabia Region Crater
ESP_024872_2175  Science Theme: Impact Processes
When impact craters form, they are generally surrounded by "ejecta": material that is thrown out from the crater by the impact and that settles onto the surrounding terrain. Sometimes there are multiple phases of material that fall to the ground (although both result from the same impact), creating the appearance of layered-ejecta.

This DLE [double layer ejecta] crater formed at the edge of an older/pre-existing crater, the rim of which deflected some of its ejecta. As it deflected the two phases of falling ejecta differently, we can use it to study how ejecta is transported and deposited. With HiRISE resolution, it may be possible for us to determine topography of the rim and then to see how high the barrier was that deflected some of the ejecta flow.

This is also an unusual crater because it is outside the Northern Plains and is relatively young.

This caption is based on the original science rationale.

Written by: HiRISE Science Team  (3 January 2012)

This is a stereo pair with ESP_017356_2175.
Acquisition date
16 November 2011

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
296.4 km (184.2 miles)

Original image scale range
63.7 cm/pixel (with 2 x 2 binning) so objects ~191 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

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

Solar longitude
30.5°, Northern Spring

For non-map projected images
North azimuth:  98°
Sub-solar azimuth:  337.1°
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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.