NASA Mars Mission: No Little Green Men -- Yet

NASA debunks rumors of new evidence of life on Mars, but its Curiosity rover continues to make many smaller discoveries. Some of NASA's latest images raise interesting questions.

NASA isn't ready to announce the discovery of life on Mars. At least, not yet.

NASA's Jet Propulsion Laboratory, which is managing the Mars Science Lab mission, tried to dampen ongoing speculation about "major new findings" from the Curiosity rover. The space agency said on Thursday that rumors about a pending announcement of historic significance are incorrect.

Instead, JPL plans to provide a public update on Dec. 3 on the first soil samples taken by the rover's instruments in the search for organic compounds. "At this point in the mission, the instruments on the rover have not detected any definitive evidence of Martian organics," JPL said in a written statement.

But NASA doesn't want to quash all hope for a breakthrough in its mission to discover signs of life on Mars. The mission has already uncovered an ancient riverbed, and "there is every expectation for remarkable discoveries still to come," the agency said.

A minor frenzy was set off on Nov. 20 when a JPL scientist was quoted as saying that Curiosity's Sample Analysis at Mars suite of instruments had uncovered data of such significance that it was "one for the history books."

[ For a guide to Curiosity's instruments, see "11 Cool Tools NASA Curiosity Brought To Mars" ]

Since Curiosity landed on Mars in early August, NASA has released scientific findings regularly as the six-wheeled rover rolls along the surface. Among the reports so far: changes in radiation on Mars are linked to daily atmospheric changes; little to no methane gas has been detected; and there's been a loss of atmosphere.

Earlier this week, NASA shared insights on a dust storm on Mars, which it has been monitoring from above using the Mars Reconnaissance Orbiter and on the ground using Curiosity’s Rover Environmental Monitoring Station. Researchers expect those dual observation methods to provide new information about why some dust storms on Mars grow larger than others. In this case, the regional dusk storm is weakening, according to NASA.

In addition to capturing soil and atmospheric samples, Curiosity is generating thousands of images of its journey. They range from mundane pictures of the planet's rock-strewn surface to a self-documentary of the six-wheeled rover and its instruments at work. Pictured above is a composite image, comprised of 55 high-res images, that NASA describes as a "self portrait" of Curiosity. Close observation reveals scoop marks in the sand where the rover's robotic arm took samples.

Some of NASA's images provide new information about Mars, while others raise questions. As the world waits and watches for further discoveries from Curiosity, these pictures in this slideshow show the scientific process at work. Image credit: NASA