Mission's End Approaching for Phoenix Lander

Written by Nancy Atkinson

The days are getting shorter for the Phoenix Mars Lander, and as fall approaches on Mars' northern plains, the scientists and engineers for the mission are quickly trying get as much done before power levels on the lander drop too low for any more scientific activities. In the image here, blue-ish white frost appears on Mars surface every day now as the temperatures continue to drop. This image was taken on the 131st Martian day or sol of the mission, October 7 here on Earth. Clearly visible are the interlocking polygon shapes that form in permafrost from seasonal freezes and thaws. These polygon patterns were seen in orbital pictures taken by the Mars Reconnaissance Orbiter, as well as other spacecraft, and are part of the evidence that Mars' north polar region harbors large quantities of frozen water.

The Phoenix Lander has dug more trenches in Mars soil in both the low troughs and high peaks of the polygons, and is scooping the soil into onboard science laboratories for analysis. About two weeks ago, Phoenix moved a rock nicknamed "Headless," about 0.4 meters (16 inches) with its robotic arm. Then soil from under the rock was scraped up by the scoop at the end of the arm and and delivered to the lander's optical and atomic-force microscopes.

Scientists are conducting preliminary analysis of this soil, nicknamed "Galloping Hessian." The soil piqued their interest because it may contain a high concentration of salts, said Diana Blaney, a scientist on the Phoenix mission with NASA's Jet Propulsion Laboratory, Pasadena, Calif.

As water evaporates in arctic and arid environments on Earth, it leaves behind salt, which can be found under or around rocks, Blaney said. "That's why we wanted to look under `Headless,' to see if there's a higher concentration of salts there."

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