vendredi 17 février 2017

A Dust Devil on Hilly Terrain & Scars of Erosion












NASA - Mars Reconnaissance Orbiter (MRO) logo.

Feb. 17, 2017

A Dust Devil on Hilly Terrain

There are many dust devils on Mars -- little twisters that raise dust from the surface. They have also cleaned dust off of the solar panels of the rovers Opportunity and Spirit, improving the solar power production. (Spirit became stuck in 2009 and ceased communication a year later.)

HiRISE sees many dust-devil tracks on Mars, but rarely captures an active feature because the images cover such small areas and because the typical time of day near 3 p.m. is past the peak heating and dust-devil activity. In this 2008 image in the Amazonis region, we got lucky, although not lucky enough to capture the whole swirl in the color strip.

The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 29.5 centimeters (11.6 inches) per pixel (with 1 x 1 binning) to 58.9 centimeters (23.2 inches) per pixel (with 2 x 2 binning)]. North is up.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.

Scars of Erosion

This large crescent dune in Kaiser Crater shows the scars of many types of seasonal erosional activities. Along its downwind slope are large gullies which are active during winter, when frost drives dune material downslope, carving out channels and creating fan-shaped aprons.

On the upwind slope (bottom), dust devil tracks are visible: dark lines and curliques created during the spring season by small wind vortices vacuuming up a thin layer of dust and exposing the dark dune sand.

This is a stereo pair with http://www.uahirise.org/ESP_021720_1330

Note: Both the cutout and the above image are rotated so that North is to the right.

The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 25.3 centimeters (10 inches) per pixel (with 1 x 1 binning); objects on the order of 76 centimeters (30 inches) across are resolved.] North is up.

Mars Reconnaissance Orbiter (MRO)

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.

Mars Reconnaissance Orbiter (MRO): http://www.nasa.gov/mission_pages/MRO/main/index.html

Images, Text, Credits: NASA/JPL-Caltech/Univ. of Arizona/Tony Greicius.

Best regards, Orbiter.ch

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