NASA scientists have found some of the key ingredients of life on Mars.
Powder drilled from rocks near the red planet's Gale crater contains sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, suggesting the terrain could have once been home to live microbes.
"A fundamental question for [Curiosity's] mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program, in a statement.
"From what we know now, the answer is yes."
Curiosity also found clay minerals from an ancient river which may have contained other types of microbes.
Scientists were surprised to find that some of the samples contained chemical compounds and levels of oxidization that are similar to the habitat of certain Earth-bound microbes.
NASA was clued into the presence of oxidation when remnants from Curiosity's drilling revealed grey, and not red, terrain.
"We have characterized a very ancient, but strangely new 'gray Mars' where conditions once were favourable for life," said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology.
"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."