Several billion years ago, Mars may well have been a pleasant place for tiny microbes to live, with plenty of water as well as minerals that could have served as food, NASA scientists said Tuesday at a news conference on the latest findings from their Mars rover. But they have yet to find signs that actual microbes did live in that oasis.

“We have found a habitable environment that is so benign and supportive of life that probably if this water was around and you had been on the planet, you would have been able to drink it,” said John P. Grotzinger, the California Institute of Technology geology professor who is the principal investigator for the NASA mission.

In drilling into its first rock, a fine-grained mudstone, the scientists said, the rover Curiosity — a self-contained science laboratory about the size of a Mini Cooper — sent back to Earth convincing evidence that Mars was once awash in water.

Plus, the Curiosity scientists identified elements in the rocks — sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon — that are some of the key ingredients of life, as well as minerals, like sulfates and sulfides, that primitive microbes could eat for food. Dr. Grotzinger said these minerals are “effectively like batteries” and can provide an energy source for life.