Now free to roam after weeks of being stuck in a sand trap,
NASA's Mars rover Opportunity is cautiously inspecting the troubling terrain at
Meridiani Planum.
Rover operators on Earth are attempting to discern what
caused the robot to run afoul
of an area now dubbed "Purgatory Dune." Part of that assessment is
using Opportunity's robot arm to study the problem area - and to plot out an
exit strategy for safely driving onward.
"It's been slow going at Meridiani lately," noted
Steve Squyres, lead scientist for the Mars Exploration Rover missions at
Cornell University in Ithaca, New York.
"We need to take a good hard look at Purgatory Dune
with the instrument arm, but we've also got to show this dune a lot of
respect... it got us once, and we don't want it to get us again. So as we're
maneuvering into position on it, we're using a great deal of caution,"
Squyres explained in an update to Cornell's Mars web site.
"We've got most of our safeguards on as we approach
Purgatory, and we've been setting the limits very conservatively, to make sure
we keep the vehicle safe in this treacherous terrain," Squyres said.
Devilish dune
Opportunity has positioned itself a few meters away from the
trouble-making dune.
"Just enough to turn around," Squyres told SPACE.com.
"Then we're going back to Purgatory to see what we can learn."
By using the extended robot arm, Squyres said researchers
hope to learn more about grain sizes of the sand, its composition, and whether
or not there's a cemented crust near the surface.
"Whatever we can learn to help us better understand
Purgatory Dune," he added.
Why wasn't the robot arm used to disrupt the dune, to help
extract the rover from its predicament?
"The arm is a precision device for placing
instruments... it's not for digging or hauling," Squyres explained.
"We were always confident that the wheels would get us out if we used them
properly...and they did."
Squyres said that, with Opportunity in position, the plan now
is to use the robot's arm and investigate the area quickly, "and then be
on our way."
"It'll feel very good finally to be moving again,"
Squyres reported via his web site update.
First mountaineering on another planet
On the other side of Mars, Opportunity's rover twin Spirit is
on the move at Gusev Crater. The robot is being maneuvered through the Columbia
Hills, and is now at the south side of an area tagged as Husband Hill.
"We've been spiraling up and around the west side of
the hill, heading generally south and gaining elevation as we go," Squyres
noted on the Cornell web site. "I've been surprised, as I think the whole
team has, at how well this part of the climb has gone so far."
Spirit has knocked off several drives of over 65 feet (20
meters) lately, with one spurt adding nearly 10 feet (3 meters) of elevation to
the rover's climb. From its vantage point, another passing dust
devil was recently caught by the robot's camera system.
There are two big questions that face the Spirit team. Will
they go for the summit? And if that's accomplished, what can be seen given the
rover's first good view to the south?
"I really don't know about the summit. We all want it,
of course...who wouldn't? We're doing the first mountaineering on another
planet, and it would be a little frustrating to get this close and not make it
to the top," Squyres said.
Take it sol by sol
Both Squyres and one of the lead Spirit drivers, Chris
Leger, are rock climbers when they are not ascending features on Mars.
"So we both want this...," Squyres said.
On the other hand, driving Spirit to the summit must make
sense scientifically.
"The summit is directly between us and the terrain to
the south that we want to explore...so going over the top may be a pretty
efficient route to the good stuff," Squyres explained. "Also, the summit really
is going to offer a pretty good view. Geologists in the field routinely climb
to the top of the highest hill to get a good look at their surroundings and
plan what they're going to do next, and we may want to do that here as well."
To be evaluated is just how hard Spirit's climb will be.
Wasting a lot of time and eating up valuable Martian days, called sols, has to
be weighed. But for now, the robot is pressing forward, Squyres added.
"So I simply don't know what's going to happen. But for
now the going is good...and we'll just take it sol by sol."
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