There is never
a dull moment for a robot on Mars.
A fleeting
dust devil comes into view -- just right for picture taking. An outcrop of rock
is found that yields insight into the planet's past. And then there's need to
trudge over and around ever-larger sand fields to reach primetime science.
Those
spunky, full of life rovers -- Spirit and Opportunity
-- continue to hit the dusty exploration trail on Mars.
Whirlwind watching
From its
vantage point up in the Columbia Hills at Gusev Crater, Spirit is hard at work
and highly productive explained Steve Squyres, the lead scientist for the Mars
Exploration Rover (MER) project at Cornell
University in Ithaca, New York.
Spirit has
been eyeing an outcrop named Methuselah, and last weekend took several hundred
megabits of Panoramic Camera images of the geology, Squyres said. Those images
have helped ground controllers to pick a spot on the outcrop to move in for
work with the robot's instrument arm, he said.
Spirit has also produced "blow by blow" movies of passing dust devils -
whirlwinds that hoist dust from the martian surface high
into the air.
"The dust
devil movies are just spectacular," Squyres told SPACE.com. "We've known these things were out there, of course, and
we've seen them at low resolution on several occasions. But to see them up
close and moving like this was a real treat. And they're big!"
The largest
dust devil recorded in the movies is more than 328 feet (100 meters) in
diameter, Squyres said.
Slipping and digging in
Spirit's
present position offers both a new view and new science, said MER science team
member, Larry Crumpler, a research curator in volcanology and space sciences at
the New Mexico Museum of Natural History and Science in Albuquerque.
Spirit's climb
to that setting wasn't easy.
"We
stumbled on this outcrop while driving away from Larry's Lookout a couple of
weeks ago. We were trying to drive up the slope towards the summit, and kept
slipping and digging in like trying to drive up a road covered with deep snow.
We were digging in...to the hubs. So we started to back down," Crumpler
explained.
"This is
one of the more exciting places yet," Crumpler added. "We are about to do some
real field geology here on the side of the Columbia Hills. We are likely to be
here for a while."
Given
Spirit's solar panel cleaning, apparently thanks to a passing dust devil, the
rover has lots of power. That being the case, the urgency to get to the summit
of the hills is somewhat less than it was before, Crumpler advised.
"So we will
have time to carefully examine this new site the way you would if you stumbled
upon it in the field here on Earth," Crumpler said. "In fact, it is just this
sort of low, small outcrop with visible evidence of tilting that one usually gets
excited about -- and learns a lot about the geology from - right here on Earth.
This is real field geology on another planet."
Story to tell
"It's
another new mission," said Ray Arvidson, Chair of Earth and
Planetary Sciences at Washington
University in St. Louis, Missouri
and the deputy principal investigator for the Mars Exploration Rovers.
Arvidson
said that for months it was clear that the rocks Spirit had in sight had a
story to tell in terms of the origin and modification of the Columbia Hills.
They were different than those seen in the plains of Gusev Crater, across which
the robot had driven from its original landing spot.
The
geometry of the rocks, their layering, how they conform to the landscape - all are
clues that scientists are using to develop multiple hypotheses about their
origin and the past history of the area.
One view,
Arvidson suggested, is that Spirit is perhaps wheeling about a set of coalesced
volcanic cinder cones.
"You need
all the observations...pieces of information to put the overall story together,"
Arvidson said. Spirit will be hard at work within the area for about a month.
The Mars machinery then has to wrap up its survey tasks and start heading southward
to follow the Sun, he explained.
Larger and larger ripples
Then
there's Opportunity on the other side of Mars,
tooling about at Meridiani Planum.
The rover
has started to rumble through what scientists called etched terrain, said
Squyres. "When you look at the etched terrain carefully, you see that there's a
lot of variability to it. Some of it has a distinct 'mottled' appearance, and
seems likely to have a lot of exposed rock. We haven't gotten to any of that
yet...though we will soon," he said.
Squyres
said that other parts of the etched terrain have a distinctive north-south
"grain" to the surface texture, but are more uniform in brightness.
"That's what
we're in now. The 'grain', it turns out, is caused by these big parallel
ripples that we've been driving through. That wasn't obvious in the orbital
images, but it's real obvious when you're down on the ground," Squyres noted.
And those
ripples have been getting larger and larger as Opportunity
has driven farther to the south. "We're handling them fine for now, but the
larger they get, the more of a challenge to driving they will pose," Squyres
said.
The next big goal for Opportunity is reaching
Erebus crater, nestled inside an even larger crater now named Terra Nova. "So
we're going to pull up to the north side of Erebus, take a good look around,
and then decide what to do next," Squyres said.
Beyond Erebus, but far off in the distance, sits another hoped for Opportunity science target: Victoria Crater.
Take home message
Thanks to
the work of Spirit and Opportunity, there's an
important take home message - this time for those blueprinting future
expeditions of humans to the red planet.
"There's a
clear message," Arvidson said. "What we're doing is
reconnaissance...understanding the geological evolution and the role of water...helping
to hone in on the sites where you want to do detailed work," he said.
At some
point in the future, there will be humans on the surface of Mars, Arvidson
said.
What's
apparent to Arvidson is that the optimal way to do exploration is with humans
and robots acting together. "You can have a dozen of these rovers moving off in
various directions. Astronauts can be directing the robots, with humans then
field-checking key areas. I look at it as an integrated system," he concluded.
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