Curiosity Delivers First Close-Up Pictures Of Martian Sand Dune

Rising to a height of about 4 meters (13 feet), the structure is located within a band of dark sand dunes known as the Bagnold Dunes, which line the northwestern flank of Mount Sharp. Curiosity reached the base of the mountain in 2014, and is currently in the process of climbing it in order to examine how the terrain changes with altitude.

At present, the rover is conducting a study into how wind moves and deposits grains of sand on Mars, where the atmosphere is much thinner than that of Earth. As can be seen from the images returned by Curiosity, Martian dunes share many similarities with terrestrial ones, consisting of a steep slope on the downwind side and a more gradual incline on the windward side.

^{Close-up image of the downwind slope of the Namib Dune. NASA/JPL-Caltech}

This occurs because the dune itself shelters sand on the downwind side, causing it to drop out of the wind and form a near-vertical cliff. As this builds up, sand avalanches are common, and while Curiosity is yet to capture one of these in action, the images show where these have previously occurred.

The Namib Dune is active, migrating at a rate of about 1 meter (3 feet) per Earth year as the Martian winds continue to sweep the sand forward. These images show the downwind face of the dune, and were taken from a distance of 7 meters (23 feet), using the rover’s mast camera.

^{Panoramic view of the Namib Dune, stitched together from component images captured by Curiosity on December 18, 2015. NASA/JPL-Caltech}

Curiosity captured the component images of these panoramas on December 18, 2015, its 1,197th Martian day on the Red Planet. Also known as a sol, each Martian day is slightly longer than an Earth day, lasting for 24 hours, 39 minutes and 35 seconds.

^{Mars's Namib Dune. NASA/JPL-Caltech}