Powdered rock extracted in February from sediment near the Gale Crater contained traces of most of the building blocks for life as we know it: sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon.
"A fundamental question for this mission is whether Mars could have supported a habitable environment," Michael Meyer, lead scientist for NASA's Mars Exploration Program, said in a statement on Tuesday. "From what we know now, the answer is yes."
The primary instrument used to pinpoint these building blocks of life is called SAM, which stands for Sample Analysis at Mars. SAM analyzes soil samples by heating them in a tiny oven and observing the gases that result. Then, scientists look for the signature left by certain elements.
The area of mudstone that Curiosity is exploring is thought to have been wet once, and could have been part of a Martian river or lake bed.
"The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms," NASA scientist Paul Mahaffy said in a statement.
Curiosity found elements in various stages of oxidization, hinting at an ancient Mars much different from the Red Planet we now know. The whitishness of the powder extracted from the rock was the first clue that the interior of the rock likely didn't undergo the oxidizing process that produces the Red Planet’s characteristic hue.
Previous rovers have been able to study the surfaces of Martian rocks, but this is the first time a NASA rover has been able to study the interior of a rock, seeing geological traces that have been sealed away from harsh surface conditions.
The rover will test another drilled sample to confirm the initial chemical findings.
The news is heartening for scientists and space enthusiasts alike, but Curiosity’s work is far from done. In a few weeks, the rover will drive to nearby Mount Sharp to investigate further, hopefully illuminating the range of possible habitats present in the area.
"We have characterized a very ancient, but strangely new 'gray Mars' where conditions once were favorable for life," Mars Science Laboratory scientist John Grotzinger said in a statement. "Curiosity is on a mission of discovery and exploration, and as a team we feel there are many more exciting discoveries ahead of us in the months and years to come."
In December, NASA announced that it was planning on sending another rover to Mars in 2020.