When the Opportunity rover landed on Mars last year, scientists were
thrilled that it made a cosmic "hole-in-one" by rolling into a crater.
But now the
robot is struggling to drive itself out of a sand trap. Time will tell whether
it's up to par for the task.
Progress is
being made on trying to remove Opportunity from
a soft-sand dune that the sporty, six-wheeled utility rover has run itself into
at its exploration site: Meridiani Planum.
And on
Mars, there are no tow trucks, at least not yet. So who are you going to call?
Dune field dilemma
"We're
going to be ready soon to start making our move at Meridiani," said Steve
Squyres, lead scientist from Cornell
University for the Mars
Exploration Rover (MER) effort.
Squyres
noted on a Cornell web site devoted to the MER project that a long hard week of
testing was undertaken at NASA's Jet Propulsion Laboratory
(JPL) in Pasadena, California.
At JPL, engineers,
scientists, outside advisors, and even the project manager have been mixing
sandy and powdery materials, digging holes and building dunes - all in an
attempt to figure out how best to get Opportunity out of its dune field
dilemma.
The
team is also busily working on why the robot dug itself into the small dune,
and what added safety-in-driving tips to follow in the future.
The
blend of sandy and powdery material brought in for testing purposes matched the
way the soil has worked itself into spaces between the cleats on Opportunity's wheels.
"We
tested with one mix of materials, decided it wasn't quite nasty enough, and
then made the mix nastier and tested again. We tested getting the rover stuck
and then unstuck in a bunch of different configurations, some of which we think
were worse than the one we've gotten ourselves into on Mars," Squyres
explained.
Small steps
"The goal of this kind of testing is to be 'conservative'...
to test under conditions that are at least as bad as -- and preferably worse
than -- what you're dealing with in reality," Squyres observed.
Soon it
will be time to put to practice what the tests have shown, Squyres said. "We've
learned quite a bit," he said, pointing out that it can take a lot
of rover wheel turns to move the Mars machine from a configuration like the one
in which it now finds itself.
"And while
it's tempting to go for it all in one shot, the smart approach is to be
cautious about it and do the job in small steps. So that's what we're going to
do," Squyres added. Moving soil bit by bit beneath Opportunity's
wheels, to enable the extraction process, is going to take time, he concluded.
Impenetrable barrier?
Is it too
dangerous to press forward, perhaps better to have Opportunity
backtrack and head for safer ground?
"Why go
forward? You could have asked us that question at the beginning of the
mission...before we even launched the rovers," Squyres responded to SPACE.com. "You go forward because the
easy stuff has been done."
Squyres
said that the rover science team has looked at the plains, down into little
craters, and know what a lot of Meridiani Planum is like.
"You don't
succeed in a mission like this just by keeping the rover alive and staying out
of trouble. You succeed by pushing hard and finding new things," Squyres
related. Before Opportunity reached the etched
terrain in which it now sits, the scientist did caution that this landscape
might turn out to be some impenetrable barrier.
"And who
knows, maybe it will be. But we were prepared for that. The risks involved in
exploring the etched terrain are part of why we spent so much time at Endurance
Crater. We had a scientific gold mine there, and we wanted to work it for all
it was worth before taking a risk in the etched terrain," Squyres emphasized.
Forward ho!
While Opportunity and Earth controllers have hit their first
impediment, Squyres stressed it's forward ho for now.
"You work
to overcome it, and then you move on. But are we going to back away from
unknown territory on the horizon, back to the safe stuff we know, because we've
hit one obstacle? Hell no," Squyres said. "If it becomes clear that we really
can't drive in this stuff, under any circumstances, then yeah, it'll be time to
find another way to use the vehicle. But we're nowhere near that point right
now."
While rover operators work
out the plan of action, Opportunity is imaging
the plains of Meridiani Planum and performing atmospheric science observations.
In the meantime, on the
other side of Mars, the Spirit rover continues its study of the Columbia Hills
within Gusev Crater.
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