After the drilling was done and the powder collected, the small laboratory on Curiosity began a series of tests. Then, earlier this month, came the surprising announcement: American scientists said the test results led them to believe there was once life on Mars.

The rock sample came from an area on Mars called Yellowknife Bay. The area had some of the chemicals required to support life as we know it. They include oxygen, hydrogen, nitrogen and carbon.

Scientists believe Mars was once a warmer, wetter environment before turning into a freezing dry desert. Michael Meyer is the lead scientist of the Mars Exploration Program. He spoke at the space agency’s headquarters in Washington.

“This was an ancient environment with the right elements, minerals indicating a near-neutral environment and slightly salty liquid water, all the pre-requisites to support life -- a habitable environment.”

Researchers say the Martian bedrock showed evidence of many periods of wet conditions. And they say there are clay minerals in the rock sample. These minerals are evidence of water.

John Grotzinger is a Curiosity project scientist at the California Institute of Technology.

“Landing there and then almost right off the bat we do find evidence of water and we see an ancient river bed. We’re now finding an environment in the near subsurface, you know not too far beneath the oxidized layer, sort of a neutral rock. All the things that we were really hoping for, to find a place that could have been habitable in its past.”