NASA's Mars rover Opportunity has made perhaps the biggest discovery
of its nearly 10-year career, finding evidence that life may have been
able to get a foothold on the Red Planet long ago.
The Opportunity rover
spotted clay minerals in an ancient rock on the rim of Mars' Endeavour
Crater, suggesting that benign, neutral-pH water once flowed through the
area, scientists said.
"This is water you could drink,"
Opportunity principal investigator Steve Squyres of Cornell University
told reporters today (June 7), explaining why the rock, dubbed
"Esperance," stands out from other water-soaked stones the rover has
studied. [Ancient Mars Could Have Supported Life (Photos)]
"This is water that was probably much more favorable in its chemistry,
in its pH, in its level of acidity, for things like prebiotic chemistry —
the kind of chemistry that could lead to the origin of life," Squyres added.
A long-lived rover
The golf cart-size Opportunity and its twin, Spirit, landed on the Red
Planet in January 2004 on three-month missions to search for signs of past water activity.
The robotic explorers found plenty of such evidence (much of it
indicating extremely acidic water, however), then just kept rolling
along.
Spirit stopped communicating with Earth in 2010 and was
declared dead a year later, but Opportunity is still going strong. In
August 2011, the six-wheeled robot arrived at the rim of the
14-mile-wide Endeavour Crater, which it has been investigating ever
since.
Opportunity has seen signs of clays in Endeavour rocks before, but in
nowhere near the concentrations observed in Esperance, researchers said.
Overall, Esperance provides strong evidence that ancient Mars was habitable.
"The fundamental conditions that we believe to be necessary for life were met here," Squyres said.
The neutral-pH water that generated the clays probably flowed through
the region during the first billion years of Martian history, he added,
stressing that it's nearly impossible to pin down the absolute ages of
Red Planet rocks without bringing them back to Earth.
NASA's Mars rover Opportunity captured this view of Solander Point
on June 1, 2013. The southward-looking scene, presented in false color,
shows Solander Point on the center horizon, "Botany Bay" in the
foreground, and "Cape Tribulation" in the far background at left.
Opportunity's
latest discovery fits well with one made recently on the other side of
the planet by the rover's bigger, younger cousin Curiosity, which found
strong evidence that its landing site could have supported microbial life in the ancient past.
Such observations could help scientists map out Mars' transition from a
relatively warm and wet world long ago to the cold and dry planet we
know today.
"All the details need to be worked out, but the more
we look, the more it fits into this kind of broad context," said
Opportunity deputy principal investigator Ray Arvidson of Washington
University in St. Louis.
Moving on
Opportunity had spent the last 20 months at a spot called Cape York, but
it has now begun to trek toward Solander Point, which rises 180 feet
(55 meters) from the surrounding Martian plains.
The mission
team is intrigued by the many layers of geological material Opportunity
can investigate at Solander Point. The area also has a north-facing
slope, which will allow Opportunity to point its electricity-generating
solar panels toward the sun during the coming southern-hemisphere
Martian winter.
The height of this winter will occur in February
2014, but Opportunity's handlers want to get the robot to Solander by
the beginning of August, so it can investigate the region and help plan
out a winter science campaign, researchers said.
There's no
reason to think Opportunity won't complete the 1.4-mile trek (2.2 km) to
Solander, or that it won't survive its sixth Martian winter; the rover
remains in good health despite its advanced age, mission officials said.
Still, the Opportunity team is taking nothing for granted.
"The rover could have a catastrophic failure at any moment," said
Opportunity project manager John Callas, of NASA's Jet Propulsion
Laboratory in Pasadena, Calif. "So each day is a gift."
Opportunity is poised to break the international record for distance traveled on another world
during the drive to Solander Point. That mark is held by the Soviet
Union's remote-controlled Lunokhod 2 rover, which traveled 23 miles (37
km) on the moon in 1973.
However, Opportunity scientists said
today that Lunokhod 2's total mileage is just an estimate, so it's tough
to know what the actual record is. They plan to hold off on any
announcements until someone can calculate a precise odometer reading for
Lunokhod 2, possibly by using measurements by moon-orbiting spacecraft.
Opportunity's odometer currently reads 22.75 miles (36.61 km).
Source
Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebookor Google+. Originally published on SPACE.com.
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