Scientists are identifying a roster of targets for Spirit to carry out up-close investigation, including the Magic Carpet. But off in the distance, arguably the most scientifically compelling feature, are rolling hills.
Engineers here at the Jet Propulsion Laboratory (JPL) have scripted a step-by-step plan for edging Spirit off its lander pedestal late Wednesday night into Thursday morning.
Late tonight, a critical splicing of a cable is scheduled. That action frees Spirit from its throne, allowing it to start turning itself for eventual egress down onto Mars surface.
Mud fights
Scientists have been studying "unusual features" that were formed as one of the rovers airbags exerted stress on the martian soil after being retracted.
"The science team looks forward to working on this problem," said John Grotzinger, a Science Team Member for the Mars exploration rovers from the Massachusetts Institute of Technology.
Grotzinger told SPACE.com that the churned up, crumpled portion of the soil does not seem to be mud, perhaps a byproduct of subsurface water. Under closer inspection with camera gear on Spirit, the feature does not mimic the mechanical behavior of a mud, he said
The true nature of the oddly cohesive disturbed soil remains contentious.
Real feel of geology
"You cant rule out exclusively that its not an artifactsomething to do with the airbag itself," Grotzinger explained.
More up-close inspection of the anomalous material is planned.
When Spirit is mobile, the robot can also use its wheels to trench into the soil, helping scientists to better assess the properties of the top most layers of martian terrain in the area.
The Gusev Crater site is marvelous, said Michael Malin, Science Team Member at Malin Space Science Systems in San Diego, California.
"I wasnt prepared for how really familiar the site looks. It has a real feel of geology," Malin added. "We dont have enough time to go to all the places that were excited about."
Rolling hills seen from Spirits Panoramic Camera system are enticing targets. "We all want to go thereand we hope the vehicles resources last long enough to do that," Malin explained.
ZOOM IN ON MARS!
Like driving the rover, you can zoom to any rock or feature
in this Jan. 8 Spirit photo with SPACE.com's Zoom Viewer. |
Explosive Guillotine
Tonights cable cutting is crucial. "Its an explosive guillotine," said Kevin Burke, JPL Egress Mechanical Lead.
Burke said that the lander upon which Spirit now rests is in whats called the "Iron Cross configuration" all petals are at the same level forming a big, flat platform. Once Spirit begins a careful, three-step rotation on the platform, the robots cameras will take two images of the intended exit ramp area.
At the moment that egress ramp direction remains a blind spot. No unobstructed pictures have been taken of exactly where the rover is to wheel onto Mars. If anything thats a little scary is revealed, an alternative direction may be picked.
Over 500 egress practice sessions have been completed over the last several years, Burke noted. "Its a very satisfying experience to finally be doing an activity that youve been preparing to do for a long time," he told SPACE.com .
Car-sized boulders
"Its staggering," said Jim Bell of Cornell University, leader of the panoramic camera team, in looking over the 360-degree view of Gusev Crater landscape.
Bell said he has been surprised at the small number of large rocks at the landing site -- although off in the distance, car-sized boulders are visible.
For Bell, as is the case for other scientists on the Mars Exploration Rover team, whether or not Gusev is indeed a lakebed remains debatable.
"I think the way we resolve it is to measure the composition of some of these materials we see. We just cant look at these pictures as beautiful as they are. We need some quantitative composition information," Bell said.
Shoreline wave action
Rover teams are chomping at the throttle to power Spirit over to a nearby crater. It is sure to contain excavated, subsurface materials. "That crater is the nearest, free, subsurface sample return," Bell said.
Bell said he and others on the team believe that Spirit should later in its mission head for the hills.
Those hills could have been an island in Mars past, Bell pointed out.
The hills are high enough, Bell said, that if Gusev was ever filled with water the nearby hillsides themselves would preserve evidence of that fact. A close examination could show past shoreline wave action and sedimentation.
"Those are all classic features you see in lake environments," Bell said. "Those hills are right at the edge of Spirits driving rangebut we should try for it."
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