Nili Fossae
HiRISE Image TRA_000883_2005This HiRISE image covers an area of Nili Fossae located on the northwestern margin of the Isidis Basin. The image covers an area in the general vicinity of terrains where the Omega instrument on board the Mars Express spacecraft has detected phyllosilicates, or clay minerals. The ancient surface is marked by numerous degraded impact craters and appears structurally complex. Much of the surface appears stripped, with remnants of a relatively darker unit appearing as mesas surrounded by talus in the lower portion of the image. Wind blown dunes comprised of relatively dark sediments are numerous. At the full resolution of the HiRISE sub image, the lighter unit covering much of the surface is seen to be intensely fractured, yet preserves many circular structures likely associated with ancient craters and other relief. The nature and origin of the fractured surface is unknown, but the fractures display little offset that would indicate they are faults. Rather, it appears that some process has disrupted the surface while preserving much of the original texture and structure.
Image TRA_000883_2005 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on October 4, 2006. The complete image is centered at 20.4 degrees latitude, 78.5 degrees East longitude. The range to the target site was 282.6 km (176.7 miles). At this distance the image scale ranges from 28.3 cm/pixel (with 1 x 1 binning) to 56.6 cm/pixel (with 2 x 2 binning). The image shown here has been map-projected to 25 cm/pixel and north is up. The image was taken at a local Mars time of 3:21 PM and the scene is illuminated from the west with a solar incidence angle of 47 degrees, thus the sun was about 43 degrees above the horizon. At a solar longitude of 115.7 degrees, the season on Mars is Northern Summer.
Images from the High Resolution Imaging Science Experiment and additional information about the Mars Reconnaissance Orbiter are available online at:
http://hirise.lpl.arizona.edu/
or
For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, 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.
