Citizen Staff Writer
ALAN FISCHER
afischer@tucsoncitizen.com
As spring arrives on the Martian southern hemisphere, weblike patterns of soil are appearing on the area’s ice-covered surface.
Images from the University of Arizona’s High Resolution Imaging Science Experiment orbiting above the planet show intricate fans of material spewed by carbon dioxide gas escaping into the atmosphere, said Candice Hansen-Koharcheck.
During the six-month Martian winter, the arctic region is covered with a frozen layer of CO2 – dry ice – between a half meter and a meter thick, said Hansen-Koharcheck, the HiRISE mission’s deputy principal investigator.
The returning sunlight heats the soil beneath the seasonal icy layer, causing underlying frozen material to sublimate, or change from solid to gas form, she said.
The gas works its way through cracks in the ice to escape into the atmosphere, delivering a shot of soil and dust carried from the surface, she said.
Prevailing winds and topography form the designs HiRISE photographed, he said.
Researchers are just beginning to analyze the images. “It will take us a while to digest what we have,” she said.
Efforts to use HiRISE to photograph the Phoenix Mars Lander spacecraft, now resting inactive on the planet’s northern arctic region following a five-month surface research mission, have been unsuccessful, she said.
Researchers had hoped to see how the craft, and its delicate solar panels, are faring as the cold, dark Martian winter approaches its landing site.
“In the north a hood of clouds came in and we had to basically give up imaging Phoenix,” she said. “The atmospheric conditions didn’t allow us to see the surface any more.
“The minute that polar hood dissipates we will start taking pictures,” Hansen-Koharcheck said.
Peter Smith, principal investigator for the UA-led Phoenix Mars Lander mission, said he hopes to try to contact the spacecraft when spring arrives at the planet’s northern region later this year and sunlight hits the craft’s solar panels.