NASA Mars Curiosity Rover: Two Years and Counting on Red Planet

This image from the Navigation Camera on NASA's Curiosity Mars rover shows wheel tracks printed by the rover as it drove on the sandy floor of a lowland called "Hidden Valley" on the route toward Mount Sharp.  

Image courtesy NASA/JPL-Caltech.

NASA's most advanced roving laboratory on Mars celebrates its second anniversary since landing inside the Red Planet's Gale Crater on Aug. 5, 2012, PDT (Aug. 6, 2012, EDT).

During its first year of operations, the Curiosity rover fulfilled its major science goal of determining whether Mars ever offered environmental conditions favorable for microbial life.

Clay-bearing sedimentary rocks on the crater floor in an area called Yellowknife Bay yielded evidence of a lakebed environment billions of years ago that offered fresh water, all of the key elemental ingredients for life, and a chemical source of energy for microbes, if any existed there.

"Before landing, we expected that we would need to drive much farther before answering that habitability question," said Curiosity Project Scientist John Grotzinger of the California Institute of Technology, Pasadena.

"We were able to take advantage of landing very close to an ancient streambed and lake. Now we want to learn more about how environmental conditions on Mars evolved, and we know where to go to do that."

During its second year, Curiosity has been driving toward long-term science destinations on lower slopes of Mount Sharp.

Those destinations are in an area beginning about 2 miles (3 kilometers) southwest of the rover's current location, but an appetizer outcrop of a base layer of the mountain lies much closer -- less than one-third of a mile (500 meters) from Curiosity. The rover team is calling the outcrop "Pahrump Hills."

For about half of July, the rover team at NASA's Jet Propulsion Laboratory in Pasadena, California, drove Curiosity across an area of hazardous sharp rocks on Mars called "Zabriskie Plateau."

Damage to Curiosity's aluminum wheels from driving across similar terrain last year prompted a change in route, with the plan of skirting such rock-studded terrain wherever feasible.

The one-eighth mile (200 meters) across Zabriskie Plateau was one of the longest stretches without a suitable detour on the redesigned route toward the long-term science destination.