Prospecting from Orbit
NASA/JPL/University of Arizona
Prospecting from Orbit
ESP_051153_2025  Science Theme: Composition and Photometry


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The combination of morphological and topographic information from stereo images, as well as compositional data from near-infrared spectroscopy has been proven to be a powerful tool for understanding the geology of Mars.

Beginning with the OMEGA instrument on the European Space Agency’s Mars Express orbiter in 2003, the surface of Mars has been examined at near-infrared wavelengths by imaging spectrometers that are capable of detecting specific minerals and mapping their spatial extent. The CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) instrument on our orbiter is a visible/near-infrared imaging spectrometer, and the HiRISE camera works together with it to document the appearance of mineral deposits detected by this orbital prospecting.

Mawrth Vallis is one of the regions on Mars that has attracted much attention because of the nature and diversity of the minerals identified by these spectrometers. It is a large, ancient outflow channel on the margin of the Southern highlands and Northern lowlands. Both the OMEGA and CRISM instruments have detected clay minerals here that must have been deposited in a water-rich environment, probably more than 4 billion years ago. For this reason, Mawrth Vallis is one of the two candidate landing sites for the future Mars Express Rover Mission planned by the European Space Agency.

This image was targeted on a location where the CRISM instrument detected a specific mineral called alunite, KAl3(SO4)2(OH)6. Alunite is a hydrated aluminum potassium sulfate, a mineral that is notable because it must have been deposited in a wet acidic environment, rich in sulfuric acid. Our image shows that the deposit is bright and colorful, and extensively fractured. The width of the cutout is 1.2 kilometers.

Written by: Paul Geissler  (4 September 2017)
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Acquisition date
25 June 2017

Local Mars time:

Latitude (centered)

Longitude (East)

Range to target site
300.2 km (187.6 miles)

Original image scale range
60.1 cm/pixel (with 2 x 2 binning) so objects ~180 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle:

Phase angle:

Solar incidence angle
35°, with the Sun about 55° above the horizon

Solar longitude
24.5°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  351.4°
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   (196MB)

IRB color
map-projected   (118MB)

Black and white
map-projected  (86MB)
non-map           (71MB)

IRB color
map projected  (32MB)
non-map           (93MB)

Merged IRB
map projected  (191MB)

Merged RGB
map-projected  (171MB)

RGB color
non map           (80MB)
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.