The Draa of Mars
NASA/JPL/University of Arizona
The Draa of Mars
ESP_034909_1755  Science Theme: Aeolian Processes
Greek  Spanish 


1080p (MP4)  
720p (MP4)  
Listen to the text  


800  1024  
1152  1280  
1440  1600  
1920  2048  
2560  2880  


PDF, 11 x 17 in  


Sandy landforms formed by the wind or aeolian bedforms are classified by the wavelength—or length—between crests. On Mars we can observe four classes of bedforms (in order of increasing wavelengths): ripples, transverse aeolian ridges (known as TARs), dunes, and what are called “draa.” All of these are visible in this Juventae Chasma image.

Ripples are the smallest bed forms (less than 20 meters) and can only be observed in high-resolution images acquired by HiRISE commonly superposed on many surfaces. TARs are slightly larger bedforms (wavelengths approximately 20 to 70 meters), which are often light in tone relative to their surroundings. Dark-toned dunes (wavelengths 100 meters to 1 kilometer) are a common landform and many are active today. What geologists call “draa” is the highest-order bedform with largest wavelengths ( greater than 1 kilometer), and is relatively uncommon on Mars.

Here, this giant draa possess steep faces or slip faces several hundreds of meters tall and has lower-order superposed bedforms, such as ripples and dunes. A bedform this size likely formed over thousands of Mars years, probably longer.

Written by: Matthew Chojnacki   (4 June 2014)

Click to share this post on Twitter Click to share this post on Facebook Click to share this post on Google+ Click to share this post on Tumblr

 Image Products: All image links are drag & drop for HiView, or click to download
B&W: map projected  non-map

IRB color: map projected  non-map

Merged IRB: map projected

Merged RGB: map projected

RGB color: non-map projected

B&W: map-projected (821MB)

IRB color: map-projected (512MB)
B&W: map-projected  (357MB),
non-map  (497MB)

IRB color: map projected  (145MB)
non-map  (421MB)

Merged IRB: map projected  (192MB)

Merged RGB: map-projected  (181MB)

RGB color: non map-projected  (405MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

About color products (PDF)
HiView main page

 Observation Toolbox
Acquisition date:06 January 2014 Local Mars time:15:12
Latitude (centered):-4.500° Longitude (East):297.183°
Range to target site:267.0 km (166.9 miles)Original image scale range:26.7 cm/pixel (with 1 x 1 binning) so objects ~80 cm across are resolved
Map projected scale:25 cm/pixel and North is upMap projection:Equirectangular
Emission angle:3.0° Phase angle:52.7°
Solar incidence angle:55°, with the Sun about 35° above the horizon Solar longitude:72.7°, Northern Spring

Context map

Usage Policy
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: Image: NASA/JPL/University of Arizona
For information about NASA and agency programs on the Web, visit: 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. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.