By Charlene Porter
Seven months after the rover Curiosity landed on Mars, scientists announced March 12 that they’ve found what they were looking for: an environment that could have supported microbial life.
Analysis of powdered material drilled out of a sedimentary rock in the Gale Crater landing site shows the territory was part of an ancient river system or an occasionally wet lake bed that was capable of sustaining certain forms of microbial life.
“We have found a habitable environment,” said John Grotzinger, Curiosity project scientist, at a March 12 briefing. He described an environment that was, in its day, “benign and supportive of life.”
The California Institute of Technology scientist said that “a microbe could have lived in, and maybe even prospered in” the environmental conditions revealed through analysis of the rock sample.
The rock sample showed traces of sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — some of the key chemical ingredients for life. The sample — the first from Mars to ever undergo this degree of analysis — showed past signs of moisture sufficient to support simple life forms and no sign of excessive acidity. The analysis also revealed traces of minerals that could have provided an electron flow, which sustains certain microbial life on Earth.
“This is fantastic,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program. Decades of Mars exploration by previous orbiters and rovers have contributed to the mission’s success in landing the craft at a site where the rover found all the elements scientists sought as evidence of a once-habitable environment on the red planet.
With the habitability question answered, Grotzinger said, the mission will now proceed in a deliberate way to search out signs of carbon, the basis for all life forms as we know them.
With success achieved so early in the Curiosity mission, will the craft be able to move forward to find a sign of life? Grotzinger pointed out that Curiosity is neither designed nor equipped as a life-detection mission.
“If there was microbial metabolism going on, we really wouldn’t have the ability to measure that,” Grotzinger said.
What Curiosity still can and will do is travel farther across the Martian surface to other interesting targets that could reveal more types of rocks and minerals that tell other, different stories about Mars.
“The team is just delighted to be waking up every morning and looking at what’s happening on this different planet,” said Paul Mahaffy, principal investigator for the sample analysis component of the Mars investigation. “It’s just tremendously exciting.”
Hundreds of scientists have contributed to Curiosity’s findings, Grotzinger said, building on the engineering and technological breakthroughs of earlier generations.