Mars may have once supported life, NASA says March 12, 2013 -- Updated 1850 GMT (0250 HKT) Photos: Mars rover Curiosity Mars rover Curiosity mars .2a (CNN) -- Dusty and desolate Mars once had conditions favorable for microbial life, NASA scientists announced Tuesday. The conclusion was based on the Curiosity rover's analysis of a rock sample drawn from an ancient stream bed on the Red Planet. The sample contained sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon -- "some of the key chemical ingredients for life," NASA said. "We have characterized a very ancient, but strangely new 'gray Mars' where conditions once were favorable for life," said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology. Read more space and science news on CNN's Light Years blog