The presence of elements like sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon in the rock sample analyzed by NASA's Curiosity shows that life could have once been possible on Mars, NASA said. The discovery of an ancient river bed along with a mildly alkaline soil now supports the idea that the Red Planet could have supported life a long time back.

The ingredients of life were found in a sample of rock "John Klein" obtained from an ancient stream bed in the Gale Crater, NASA said. The rock was found to be 20 to 30 percent clay.

Curiosity had obtained the rock sample Feb. 8, SPACE.com had earlier reported. Interestingly, the color of the sample was found to be gray and not the typical orange color of the planet. 

"A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington, in a news release from the agency. "From what we know now, the answer is yes."

Researchers at NASA obtained data about the rock sample from the rover's Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments. Analysis of the sample shows that the area that is currently being explored by the Curiosity rover was actually the bed of a river system. The rock sample has clay and sulfate minerals. Researchers also say that the region where the rock sample was obtained would have earlier been a good place for microbes to live, as the place wasn't found to be too acidic or harsh.

Researchers have also found evidence of calcium sulfate with the clay, suggesting that the soil in this region is mildly alkaline.

"I feel giddy. I have an image now of possibly a lake, a freshwater lake, on a Mars with probably a thicker atmosphere," said John Grunsfeld, a former astronaut who is currently an administrator for the space agency's Science Mission Directorate, reports Los Angeles Times.

The area that Curiosity is currently exploring - Yellowknife Bay - is about half a mile from where the Curiosity landed Aug. 5, 2012. The rover will now be moving toward Mt. Sharp, which is a 3-mile-high mound on the Gale Crater, Los Angeles Times reported.  The exploration of Mt. Sharp is expected to reveal the geological past of the planet and provide evidence that the planet had once supported life.

"We have characterized a very ancient, but strangely new 'gray Mars' where conditions once were favorable for life. 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," said John Grotzinger, Mars Science Laboratory project scientist at the California Institute of Technology in Pasadena, Calif.