14 DAY TRIAL // Engineers from the jet Propulsion Laboratory, in Pasadena, California, have recently obtained one of the most peculiar pictures that the rover Spirit ever sent back from the Red Planet. By combining three photographs taken seconds apart from each other, and snapped in different color filters, they obtained the first picture of a dust devil on Mars that looks like a rainbow. The robot is still stuck in a patch of loose soil known as “Troy,” as experts continue their efforts to devise escape strategies, ScienceDaily informs.
The special-effect shot taken recently shows the devil as it moves in front of Spirit's camera, and then disappears out of the frame. The colors that appear in the photo are due to the special filters that were used to take the pictures, all sensitive to different wavelengths of visible light. They were snapped on the 1,919th Martian day of the robot's mission, May 27th, 2009, back on Earth.
According to experts, the dust devils appeared on the Red Planet when the same conditions were met as on Earth – the Sun heats the surface, and creates a layer of hot air just above it. Being less dense, that air tends to rise, picking up the finer sand particles on the surface and sending them upwards.
In the five years since Spirit has been on Mars, it has pictured more than 650 dust devils, confirming that they are, in fact, quite regular phenomena that occur when the right conditions are met, just like back home. Unfortunately, the last one was taken from Troy, the patch of soil the rover has been stuck in since early May. Despite several attempts at removing it from the ground, the 185-kilogram (408-pound) robot is still trapped up to its hubcaps in sand, and engineers at JPL are using a replica in a specially designed sandbox to calculate possible scenarios.
“Mars rover engineers at JPL are winding down testing of different escape maneuvers using a test rover in a sand box filled with soil to mimic the Martian surface. It is possible that in early August the first extraction attempts with Spirit rover, which is dug-in on Mars, might take place. This week, longer-duration test runs continued, and the team drove the rover several meters, or yards, forward and uphill in a crab-like position. These long-duration drives will continue through the end of next week,” an update on NASA's site dedicated to the rover, Free Spirit, reads.
“Meanwhile, observations from the Mars Climate Sounder instrument on NASA's Mars Reconnaissance Orbiter indicate to scientists that a large regional storm is developing. Right now the dust storm is not near Spirit or its twin, Opportunity, but scientists will continue to monitor it as it develops. Since Mars is still in the dust storm season, it is possible (and perhaps even probable) that the storm will continue to grow over the next few days,” it adds.