Mars Underground Exposed:  The Central Peak of Alga Crater
Mars Underground Exposed: The Central Peak of Alga Crater
ESP_060978_1555  Science Theme: Composition and Photometry
The most habitable places on Mars now and in the past are underground, where water is or was much more stable than at the surface and protected from energetic particle radiation.

Large impact craters have central rebounds that uplift buried strata from miles below the surface. Often these central uplifts reveal colorful rocks with diverse minerals, including ones altered by prolonged contact with water.

Alga Crater is located in the southern highlands near a large flood-channel called Ladon Valles. The image cutout shows enhanced (infrared-shifted) color.

Written by: Alfred McEwen (audio: Tre Gibbs)  (16 September 2019)
Acquisition date
30 July 2019

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
258.1 km (160.4 miles)

Original image scale range
25.8 cm/pixel (with 1 x 1 binning) so objects ~77 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
64°, with the Sun about 26° above the horizon

Solar longitude
59.7°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  48.3°
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   (495MB)

IRB color
map-projected   (314MB)

Black and white
map-projected  (246MB)
non-map           (245MB)

IRB color
map projected  (82MB)
non-map           (253MB)

Merged IRB
map projected  (121MB)

Merged RGB
map-projected  (111MB)

RGB color
non map           (215MB)
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.