From the Mars Reconnaissance Orbiter comes a remarkable photo that reveals a 37,000 square-kilometer (almost 23,000 miles) dust storm that moved counter-clockwise through the Phoenix landing site on October 11. The storm moved west to east, and weakened considerably by the time it reached the lander. This tamer storm put the spacecraft in a better than expected situation, said Ray Arvidson of Washington University in St. Louis, the lead scientist for Phoenix's Robotic Arm. Image credit: NASA/JPL-Caltech/Malin Space Science Systems

Despite the storm having temporarily lowered the Phoenix's solar power the team is back investigating the Red Planet's northern plains. This was the result of increasing opacity in the atmosphere from the storm that decreased the power reaching the Phoenix's solar arrays. So on Martian days, or sols, 135-136 of the mission (October 11-12), Phoenix scientists and engineers curtailed many of the lander's science activities, such as collecting some data from its onboard science laboratories.

The lander is currently kept busy using its power to analyze soil samples, collect atmospheric data, and conduct other activities before the cold of fall and winter stop Phoenix. This dust storm is a harbinger of more wintry and volatile weather to come. As Martian late summer turns into fall, the Phoenix team anticipates more dust storms, frost in trenches, and water-ice clouds. They look forward to collecting data and documenting this "most interesting season," Arvidson said.

The Phoenix team tracked the dust storm last week through images gleaned from the Mars Reconnaissance Orbiter's Mars Color Imager. The imager's team estimated that after the dust storm passed through Phoenix's landing site on Saturday, the dust would gradually decrease this week.