NASA-International Space Station

Martian landforms shaped by winds, water, lava flow, seasonal icing and other forces are analyzed in 21 journal news based on data from a camera orbiting Mars.

The research in a January special issue of Icarus testifies to the variety of the planet being examined by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Examples of the findings include

• Valleys associated with light-toned layered deposits in numerous locations along the plateaus neighboring to the largest canyon system on Mars suggest low-temperature alteration of volcanic rocks by acidic water both before and after formation of the canyons.


• The youngest flood-lava flow on Mars, found in the Elysium Planitia region and covering an area the size of Oregon, is the product of a particular eruption and was put in place passionately over a span of several weeks at most.


• New details are experimental in how seasonal disappearance of carbon-dioxide ice sheets in far-southern latitudes imprints the ground with fan-shaped and spider-shaped patterns via venting of carbon-dioxide gas from the undersurface of the ice.

HiRISE is operated by the University of Arizona, Tucson, and was built by Ball Aerospace & Technologies Corp., Boulder, Colo. It is one of six instruments on NASA's Mars Reconnaissance Orbiter, which is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., and was built by Lockheed Martin Space Systems, Denver. The U.S. Geological Survey Astrogeology Science Center, Flagstaff, Ariz., played a extraordinary role in preparation of the special issue, providing two guest editors and authorship of multiple papers. For more information, see http://hirise.lpl.arizona.edu/

NASA's Phoenix Mars Lander, its backshell and its heatshield are observable within this enhanced-color image of the Phoenix landing site taken on Jan. 6, 2010 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.

With early spring at the Phoenix landing site comes progressive sublimation of carbon-dioxide frost that has blanketed the lander and neighboring terrain throughout the winter. During the long polar-winter night, atmospheric carbon dioxide freezes onto the surface, building up a layer of ice roughly 30 centimeters (about one foot) thick. In the spring this frost returns to atmosphere gas (sublimates) over the course of numerous months. This image, part of a seasonal frost monitoring series, shows some areas of bare ground are beginning to be exposed. However, widespread frost patches remain in the topographic lows, such as the troughs of the local polygonally patterned surface.

In HiRISE images acquired during the last Martian summer, the solar arrays on the lander were obviously discernable from their distinctive bluish color. For example, see the sub image at http://hirise.lpl.arizona.edu/PSP_008855_2485 from June 16, 2008.

The springtime picture here has green boxes around the backshell (top), heat shield, and lander (bottom). The solar arrays are not discernable in this new image, probably because the patchy frost efficiently camouflages them. Even when the frost has entirely sublimated, dust deposited during the winter may obscure them. The parachute attached to the backshell is also not obvious in this image, and we'll see if it reappears in later images. Also gone are the dark halos around the lander, backshell, and heat shield, again due to cyclic frost, dust or both. This and future images will help standardize expectations for finding the Mars Polar Lander hardware, which encountered Mars in 1999.

This picture covers a swath of ground about 300 meters (about 1,000 feet) wide, at 68.2 degrees north latitude, 234.3 degrees east longitude. It is one creation from HiRISE observation ESP_016160_2485. Other image products from this observation are available at http://hirise.lpl.arizona.edu/phoenix-spring.php .

The University of Arizona, Tucson, operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.