Curiosity is set to join Opportunity, a NASA rover that has been working on Mars for more than six years. Opportunity has been working alone since another rover, Spirit, stopped functioning last year.

In a teleconference on Monday, NASA officials said that the agency's scientists have gained enough confidence in the precision of the landing technology aboard the Mars Science Laboratory spacecraft to change its landing plans. The rover is now slated to touch down close to Mount Sharp, which is in the center of Gale Crater.

Scientists are eager to analyze the rock layers in the mountain to find out if the area has, or ever had, environmental conditions favorable to .

Prior to changing the target site, the craft was to land within an area measuring about 12 miles wide and 16 miles long. The new target site measures 4 miles wide and 12 miles long.

"We have been preparing for years for a successful landing by Curiosity, and all signs are good," said Dave Lavery, Mars Science Laboratory program executive at NASA. "However, landing on Mars always carries risks, so success is not guaranteed. Once on the ground we'll proceed carefully."