NASA Unveils Plan To Unstick A Mars Rover

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NASA has announced a plan to extricate its rover Spirit, which has been stuck in a Martian sand trap since April.

  • NASA's Spirit rover found an angular piece of volcanic lava that proves to be a great choice for a photographic study of Martian light and shadow.
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    NASA's Spirit rover found an angular piece of volcanic lava that proves to be a great choice for a photographic study of Martian light and shadow.
    Photos courtesy of NASA/JPL/Cornell University
  • The shadow of the camera mast against a background of sand, rocks and a small dust-filled impact crater makes for a nice self-portrait of the Spirit rover.
    Hide caption
    The shadow of the camera mast against a background of sand, rocks and a small dust-filled impact crater makes for a nice self-portrait of the Spirit rover.
  • While driving over the reddish rocks and soils of Mars, the rover's wheels dig below the thin dusty layer and reveal the darker, brownish soils below. The circular tracks are "pirouettes" that the rovers occasionally do to align their radio antennas for best possible communications.
    Hide caption
    While driving over the reddish rocks and soils of Mars, the rover's wheels dig below the thin dusty layer and reveal the darker, brownish soils below. The circular tracks are "pirouettes" that the rovers occasionally do to align their radio antennas for best possible communications.
  • Spirit rover watches a Martian sunset. The daytime sky is reddish-brown because it holds so much suspended dust. The same dust turns the sky bluish at sunset.
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    Spirit rover watches a Martian sunset. The daytime sky is reddish-brown because it holds so much suspended dust. The same dust turns the sky bluish at sunset.
  • A view from high in Mars' Columbia Hills, looking over Spirit's right solar panel "wing" and down into the Tennessee Valley. Just like on Earth, hills and ridges on Mars are windy places. The wind creates sand dunes and scours rocks, and it sometimes even cleans the dust off the rover's solar panels — increasing the electrical power and longevity of the mission.
    Hide caption
    A view from high in Mars' Columbia Hills, looking over Spirit's right solar panel "wing" and down into the Tennessee Valley. Just like on Earth, hills and ridges on Mars are windy places. The wind creates sand dunes and scours rocks, and it sometimes even cleans the dust off the rover's solar panels — increasing the electrical power and longevity of the mission.
  • Among the most surprising discoveries from the Opportunity rover were these small, spherical, ball-bearing-sized grains of rock that litter the ground by the millions. These are iron-rich mineral grains most likely precipitated out of ancient near-surface water on Mars. The Rover Science team dubbed these little grains "blueberries."
    Hide caption
    Among the most surprising discoveries from the Opportunity rover were these small, spherical, ball-bearing-sized grains of rock that litter the ground by the millions. These are iron-rich mineral grains most likely precipitated out of ancient near-surface water on Mars. The Rover Science team dubbed these little grains "blueberries."
  • Once in a while the rovers are commanded to dig a trench with their wheels, so scientists can study the shallow subsurface. This trench, about 3 inches deep, was dug out right next to the rover's landing platform. The rover's robotic arm is extended, readying its instruments to make chemical measurements inside the trench.
    Hide caption
    Once in a while the rovers are commanded to dig a trench with their wheels, so scientists can study the shallow subsurface. This trench, about 3 inches deep, was dug out right next to the rover's landing platform. The rover's robotic arm is extended, readying its instruments to make chemical measurements inside the trench.
  • The setting sun casts a long rover shadow as Opportunity prepares to drive down into Endurance crater, a stadium-sized hole in the ground filled with sand dunes and layered rocks.
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    The setting sun casts a long rover shadow as Opportunity prepares to drive down into Endurance crater, a stadium-sized hole in the ground filled with sand dunes and layered rocks.
  • This "false color" view of sand dunes at the bottom of Endurance crater is scientifically useful for distinguishing among iron-bearing minerals within the sand. The rover cameras can see farther into the ultraviolet and infrared than human eyes can. Scientists use that capability to create false color images of Martian terrain.
    Hide caption
    This "false color" view of sand dunes at the bottom of Endurance crater is scientifically useful for distinguishing among iron-bearing minerals within the sand. The rover cameras can see farther into the ultraviolet and infrared than human eyes can. Scientists use that capability to create false color images of Martian terrain.
  • Meridiani Planum, home to the Opportunity rover, is a vast plain dominated by 8- to 12-inch sandy dunes and ripples that go on and on for as far as the rover's "eyes" can see.
    Hide caption
    Meridiani Planum, home to the Opportunity rover, is a vast plain dominated by 8- to 12-inch sandy dunes and ripples that go on and on for as far as the rover's "eyes" can see.
  • Opportunity's "footprint" in the crusty, "blueberry"-covered sands of Meridiani Planum, Mars, on mission Day 605.
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    Opportunity's "footprint" in the crusty, "blueberry"-covered sands of Meridiani Planum, Mars, on mission Day 605.
  • The Spirit rover's right front wheel motor died about two years into the mission. However, the bad luck of decreased mobility ended up turning into good fortune, because the stuck wheel created a 6-inch-wide trench that dug up bright, salty, hydrated soils that would not have been discovered otherwise. These water-bearing deposits reveal that this part of Mars was very likely more Earth-like at...
    Hide caption
    The Spirit rover's right front wheel motor died about two years into the mission. However, the bad luck of decreased mobility ended up turning into good fortune, because the stuck wheel created a 6-inch-wide trench that dug up bright, salty, hydrated soils that would not have been discovered otherwise. These water-bearing deposits reveal that this part of Mars was very likely more Earth-like at one time.

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The space agency will begin transmitting commands to the exploration robot on Monday. Based on tests conducted on Earth this spring that simulated conditions at the Martian site, researchers do not expect the effort to be quick or easy.

A team testing ways to un-stick Mars rover Spirit. i

A team at NASA tests possible maneuvers for the Mars rover Spirit to use to escape the soft soil it has been stuck in since April. NASA/JPL-Caltech hide caption

itoggle caption NASA/JPL-Caltech
A team testing ways to un-stick Mars rover Spirit.

A team at NASA tests possible maneuvers for the Mars rover Spirit to use to escape the soft soil it has been stuck in since April.

NASA/JPL-Caltech

"This is going to be a lengthy process, and there's a high probability attempts to free Spirit will not be successful," said Doug McCuistion, director of the Mars Exploration Program.

Spirit has six wheels, though one stopped working in 2006. The first commands will tell the rover to rotate its five working wheels forward approximately six turns. NASA engineers expect that severe wheel slippage is likely, with barely perceptible forward progress in this initial attempt.

When Spirit returns data the next day, engineers will look at the results, and use that information to develop and send commands for a second attempt. NASA plans to continue escape efforts, if necessary, until early 2010.

"Mobility on Mars is challenging, and whatever the outcome, lessons from the work to free Spirit will enhance our knowledge about how to analyze Martian terrain and drive future Mars rovers," McCuistion said. "Spirit has provided outstanding scientific discoveries and shown us astounding vistas during its long life on Mars, which is more than 22 times longer than its designed life."

Built To Last

The two Mars rovers, Spirit and Opportunity, have been at work on Mars since January 2004. The mission was originally designed to be only three months long.

Jim Bell of Cornell University is the scientists in charge of the panoramic cameras, or PanCams. These are the stereo cameras that have been sending back remarkable pictures.

"We never imagined, of course, that they will be doing this well. But the PanCams passed our quarter-million image mark," said Bell.

When asked whether the rover's technology was designed to last this long, or if it's just luck, Bell said: "I mean you can't really talk about overdesigning for something that you never built before. Sony can tell you exactly how long any of its TVs are going to last, because they've built millions of them. But with space vehicles, they're one-offs, they're one-shot deals."

Or this case two-shot deals, because there are two PanCams working on Mars: one on the rover Opportunity, and the other on Spirit.

And it's Spirit that's gone and got itself into trouble.

Stuck In A Sand Trap

Last April, as it was driving south, it broke through a thin layer of crusty soil. What was underneath was extremely fine-grain soil, and Spirit's wheels quickly got stuck.

"We haven't found a clear solution how to get Spirit out of its predicament," said John Callas, the rover project manager. He said the situation is challenging. One of the six rover wheels stopped working three years ago, so moving has been tough for a while.

Now another wheel may be stuck. And the rover's underbelly, what Callas calls "the belly pan," is perilously close to some rocks beneath the rover.

And perhaps worst of all, every time they've tried to move the rover, it's sunk a little deeper. Sinking much farther would be disastrous.

"Because if you put the belly pan of the rover on the ground, that's pretty much game over in terms of trying to get the rover out," said Callas. "Because then you would be burying the weight of the rover on the belly pan and not on the wheels, where you need the traction."

So after months of working on the problem, Callas said on Monday, the team will send the rover instructions to try moving out of the sand the way it came in. NASA managers sound hopeful — but not optimistic — that this will work

Opportunity Is Still Knocking

On the other side of Mars, rover Opportunity is still rolling along. It's on a 12-mile trek across a sandy plain to a large crater, called Endeavor, that scientists want to explore.

Bell said Opportunity is still making cool discoveries. Just the other day it came across a large rock.

"The hope is that this is a piece of Mars that comes from somewhere else," Bell said. "It was thrown out by a big impact crater, and it just happens to have landed in our path. And this is kind of a free way to sample more of Mars than we have been sampling where we are."

One more feather in the rovers' already well-decorated caps.

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