In this photo provided by NASA, a view of the lower reaches of Mount Sharp is shown in a cropped image taken with a 34-millimeter Mast Camera on NASA's Curiosity rover on August 18, 2012 on Mars. (NASA via Getty Images)
A Martian crater rock has revealed chemistry that could have once supported living things on the Red Planet, NASA scientists reported on Tuesday.
Announced at NASA headquarters, the rover's analysis of powder drilled from bedrock in a dry lake bed points to success of the $2.5 billion mission's goal, which all along was to find evidence of past habitable conditions on Mars.
"The key thing here is an environment that a microbe could have lived in, maybe even prospered," said mission chief scientist John Grotzinger of Caltech. Drilling into bedrock on what appears to have once been a lake bed more than 3 billion years ago, the rover probe returned a sample of clay formed in freshwater and laced with sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, all vital to the biochemistry of life. "We found a habitable environment that's largely benign. You could have drank the water that flowed," Grotzinger says.
The rover landed inside Gale Crater on Mars in August in a dramatic seven minute rocket-deployed landing and quickly found evidence of past water flow inside the crater. Over the last seven months, the rover has rolled to a rocky outcrop nicknamed "Yellowknife Bay" by mission scientists, where they drilled into the bedrock, first discovering a gray "mudstone" clay underneath the rusty dust carpeting Mars.
"Now we know from ground truth chemical measurements that mudstone containing clays provided an environment that is not extremely harsh, consistent with, for example, microbial life at some time," says University of California, Berkeley, biochemist Richard Mathies, who was not part of the mission. "This is a strong argument for NASA to push for flying higher capability instruments that actually do have the capability and sensitivity needed to search for the presence of life on Mars."
For now, the rover will continue probing the rock outcrop, moving on to similar settings that might yield evidence of even more complex chemicals that may hint at ancient biochemistry. Grotzinger pointed to microbes on Earth that make a living off of simple chemical reactions with minerals as examples of the kind of life that could have survived in the environment at Gale Crater. They would have thrived, he added, "about the time we first see life preserved on Earth."
The Curiosity rover is essentially a mobile chemistry lab, "not a life detection machine," unable to detect any fossil traces of such ancient microbes, noted mission scientist Paul Mahaffy of NASA's Goddard Spaceflight Center in Greenbelt, Md., at the briefing. NASA's next Mars lander planned for 2020 will likely need to have such a capability, Mathies suggested, as a result of the new findings.
Mount Sharp, or Aeolis Mons, an 18,000-foot-high mountain in the center of the crater, remains the ultimate destination of the rover. The mountain is ringed with clay deposits that have been pre-empted to some extent by Tuesday's announced discovery.
"We now have food to imagine a very different Mars than the one we see today," says former astronaut John Grunsfeld, NASA's deputy administrator, pointing to the possibilities of lakes and snow-capped mountains once dotting the now-desert planet. "It makes me want to go," he said.
"I'll go, John," replied Grotzinger. "Just bring me back."