Scientists on Monday showed off a high-resolution, full-color, 360-degree panorama of the Spirit rover's surroundings on Mars, as well as an up-close view of a mysterious curled-up soil scraping nicknamed the "Magic Carpet."
The curl of soil, which measures only inches (centimeters) wide and perhaps a tenth of an inch (1 to 2 millimeters) thick, was apparently scraped up when the rover retracted its airbags after rolling to a stop in Mars' Gusev Crater on Jan. 3, mission scientists said during a news briefing at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
One of the science team members, geologist John Grotzinger of the Massachusetts Institute of Technology, said the Magic Carpet was intriguing because it showed that the soil in the area wasn't necessarily brittle but was capable of a "plastic sort of deformation." He and fellow geologist Michael Malin acknowledged that the scraping looked like mud in low-resolution imagery. But they insisted that dry, fine-grained soil could exhibit the same quality.
Grotzinger said the clumpiness of the Martian soil could be a case of static cling. "If there are clay minerals ... they have unsettled charges, so there can be electrostatic attractions," he said.
Malin, meanwhile, said past missions have shown that dry Martian soil could take on some of the characteristics of a fluid.
"It'd be very, very unusual or odd to have any water in more than a trace amount that would have a physical property effect," Malin said. "Very fine materials, actually in the absence of water, are capable of doing very strange things."
Malin's San Diego-based company, Malin Space Science Systems, has provided imaging services for several of NASA's Mars probes — and he said the ground-level view of the terrain looked "very familiar," based on his experience with orbital views.
"This site looks very normal," he said. "We're all excited. It looks like we could just walk out there and start working."
Malin praised the resolution of the pictures provided by Spirit's panoramic camera. Monday's panorama was assembled from three sets of 75 images, with each image comprising more than a million pixels. The resulting file was so large that the resolution had to be reduced for display on Monday morning, Malin said. The full-size image would "jam any download you ever try to perform," he said.
Scientists said the scraped soil and dragged pebbles in the trail of Spirit's airbags would be among the first subjects of investigation once the rover rolled off its landing platform — a milestone that's likely to come late Wednesday or early Thursday.
Since its landing, Spirit has been making observations from an elevated landing platform — and making preparations for the rollout. Its primary exit route is partially blocked by puffed-up airbags that can't be fully deflated, so engineers have planned a maneuver that calls for the six-wheeled rover to back up slightly, turn 120 degrees and roll off a secondary ramp to the northwest.
The operation was rehearsed Sunday night, using a practice rover that is sitting in a sandbox test area at JPL.
"Everything went really well there, no new issues," mission manager Arthur Amador told journalists, "so it looks like we're good to go with our continued plan for egress."
The plan calls for the turn to be made in three stages between now and Wednesday night. A final cable connecting the rover to its landing platform would be cut late Monday or early Tuesday, using a pyrotechnic-armed cable-cutter that Kevin Burke, the lead mechanical systems engineer for egress, called an "explosive guillotine."
"We're about to kick the baby bird from its nest," Burke said.
Looking for water's traces
During its 90-day mission, Spirit will use its cameras and spectrometers as well as a microscopic images and a grinding tool to analyze the rocks and soil around the landing site, looking for evidence that liquid water could have persisted at the site long enough for life to develop. Scientists believe the flat terrain within Gusev Crater could have been an ancient lakebed.
Astrobiologists are "following the water" in Mars' geological history because on Earth, life has been found virtually everywhere there is liquid water.
Malin said he was intrigued by the fractured rocks seen in the Gusev Crater panorama. In his view, this indicated that "at some time in the history of this surface, water was involved in the physical breakdown of the rocks." But he acknowledged that other scientists believe the fracturing could have been caused by other means — for example, the many impacts that have pockmarked Gusev Crater's interior with smaller craters.
Spirit represents one-half of an $820 million, "two-for-one" mission to Mars: Its twin, the Opportunity rover, is due to touch down on Jan. 24 in Meridiani Planum, a hematite-rich region on the other side of Mars. Spirit was launched last June, and Opportunity in July. Spirit followed a roughly 300-million-mile (500-million-kilometer) arc to the Red Planet, which is currently about 110 million miles (175 million kilometers) from Earth.