Drilling into a rock near its landing spot, the Curiosity rover has
answered a key question about Mars: The red planet long ago harbored
some of the ingredients needed for primitive life to thrive.
Topping the list is evidence of water and basic elements that teeny organisms could feed on, scientists said Tuesday.
"We have found a habitable environment that is so
benign and supportive of life that probably if this water was around and
you had been on the planet, you would have been able to drink it," said
chief scientist John Grotzinger of the California Institute of
Technology.
The discovery comes seven months after Curiosity
touched down in an ancient crater. Last month, it flexed its robotic arm
to drill into a fine-grained, veiny rock and then tested the powder in
its onboard labs.
Curiosity is the first spacecraft sent to Mars that
could collect a sample from deep inside a rock, and scientist said they
hit pay dirt with that first rock.
Mars today is a hostile, frigid desert, constantly
bombarded by radiation. Previous missions have found that the planet was
more tropical billions of years ago. And now scientists have their
first evidence of a habitable environment outside of Earth.
This was an environment where microbes "could have lived in and maybe even prospered in," Grotzinger said.
The car-size rover made a dramatic
"seven-minutes-of-terror" landing last August near the planet's equator.
As high-tech as Curiosity is, it lacks the tools to detect actual
microbes, living or extinct. It can only use its chemistry lab to
examine Martian rocks to determine the kind of environment they might
have lived in.
The analysis revealed the rock that Curiosity bore
into contained a chemical soup of sulfur, hydrogen, oxygen, nitrogen,
phosphorus and simple carbon - essential chemical ingredients for life.
Also present were clay and sulfate minerals, signs that the rock formed
in a watery environment.
NASA rovers Opportunity and Spirit - before it fell
silent - also uncovered evidence of a wet Martian past elsewhere on the
planet, but scientists think the water would have been too acidic for
microbes.
The ancient water at Curiosity's pit stop -
possibly a former lake bed - appears to be neutral and not too salty. It
previously found a hint of the site's watery past - an old streambed
that the six-wheel rover crossed to get to the flat bedrock.
Curiosity has yet to turn up evidence of complex
carbon compounds, fundamental to all living things. Scientists said a
priority is to search for a place where organics might be preserved.
The drilled rock isn't far from Curiosity's landing
spot in Gale Crater; the rover is ultimately headed to a mountain in
the crater's middle. Images from space spied signs of clay layers at the
base of the mountain - a good spot to hunt for the elusive organics.
It has been slow going as engineers learn to handle
the rover, which is far more tech-savvy than anything that has landed
before on Earth's planetary neighbor.
Over the years, Mars spacecraft in orbit and on the
surface have beamed back a wealth of information about the planet's
geology. Scientists have also been able to study rocks from Mars that
have occasionally landed on Earth.
The latest news comes during a lull in the
two-year, $2.5 billion mission. Curiosity has been prevented from doing
science experiments as engineers troubleshoot a computer problem.
Scientists still plan to drive toward the mountain,
but not until Curiosity drills into another rock at its current
location. Since flight controllers on Earth will be out of touch with
Mars spacecraft for most of next month due to a planetary alignment, the
second drilling won't get under way until May.
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Online: NASA: http://www.nasa.gov/mission_pages/msl
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