NASA Rover Arrives at Huge Mars Crater After 3-Year Trek

A portion of the west rim of Endeavour crater sweeps southward in this color view from NASA's Mars Exploration Rover Opportunity. This crater — with a diameter of about 14 miles (22 kilometers) — is more than 25 times wider than any that Opportunity has previously approached during the rover's 8 years on Mars. CREDIT: NASA/JPL-Caltech/Cornell/ASU View full size image

This story was updated at 1:11 p.m. EDT.

NASA's Mars rover Opportunity has finally arrived at the giant crater Endeavour, after nearly three years of intrepid driving across the surface of the Red Planet.

The golf cart-sized rover made landfall at its destination yesterday (Aug. 9) when it pulled up to a vista called Spirit Point on the rim of Endeavour crater, NASA officials announced today. Endeavour is a vast scar in Martian surface that is about 14 miles (22 kilometers) across.

"It's a blast," the rover's deputy principal investigator, Ray Arvidson, told SPACE.com. "It's a brand-new mission."

The 7-year-old Opportunity has been aiming for Endeavour crater since mid-2008, when it left a smaller crater (called Victoria) after a two-year pit stop. The aging rover is expected to spend years at Endeavour, if it lasts that long, in order to study rocks at the site that have never been seen before.

"NASA is continuing to write remarkable chapters in our nation's story of exploration with discoveries on Mars and trips to an array of challenging new destinations," NASA chief Charles Bolden said in a statement announcing the rover's Endeavour crater arrival. "Opportunity's findings and data from the upcoming Mars Science Laboratory will play a key role in making possible future human missions to Mars and other places where humans have not yet been." [Latest Photos from NASA's Mars Rover Opportunity]

Exploring Endeavour crater

At Endeavour crater, scientists are hoping to find much older rocks than those examined by Opportunity during its first seven years on the Red Planet.

Arvidson said Opportunity will likely not enter Endeavour crater, though it has explored the interiors of big Martian craters in the past. The interior of Endeavour looks to contain rocks made of the same material the rover has seen before.

The rim of the crater, however, is another story entirely. The rocks there are older than any Mars terrain studied by Opportunity, and could provide a new glimpse into the planet's history and water story, Arvidson said.

"I think there's much more interest in driving around the perimeter of the rim," he added.

Endeavour became a tantalizing destination after NASA's Mars Reconnaissance Orbiter detected clay minerals that may have formed in an early warmer and wetter period on the planet.

New research based on observations by the Mars Reconnaissance Orbiter observed dark lines and seasonal changes in slopes carved into the Martian surface that appear most likely to have been formed by flowing salty, briny water. 

The new findings, which present the strongest evidence yet for liquid water on the surface of Mars, are bolstering the search for extraterrestrial life.

"We're soon going to get the opportunity to sample a rock type the rovers haven't seen yet," Matthew Golombek, Mars Exploration Rover science team member at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said in a statement. "Clay minerals form in wet conditions so we may learn about a potentially habitable environment that appears to have been very different from those responsible for the rocks comprising the plains." [Video: Opportunity's 7 Years of Mars Roving]

Opportunity and Spirit

The name Spirit Point, at the crater's rim, informally commemorates Opportunity's twin rover, NASA officials said. The Spirit rover stopped communicating to its ground operators in March 2010, and the mission officially ended in May after several unsuccessful attempts to revive the rover.

"Our arrival at this destination is a reminder that these rovers have continued far beyond the original three-month mission," said John Callas, Mars Exploration Rover project manager at JPL.

Opportunity landed on Mars in mid-January 2004, two weeks after its sister robot Spirit. Opportunity has been exploring the vast plains of Mars' Meridiani Planum region, while Spirit set down inside the huge Gusev Crater.

Both rovers far outlasted their initial planned mission, but only Opportunity survived the harsh, repeated dust storms, winters and other hazardous obstacles on the Martian surface.

"It's totally out of warranty," Arvidson said with a laugh.

The longevity of the Mars rovers has come as a surprise to the mission's team members, particularly the resilience of Opportunity.

"Never in my wildest dreams," Arvidson said, adding that some rover team members set up a pool for when the rovers would succumb to the harsh environment on Mars. "We had lotteries, without cash, and we're so far beyond any of the numbers."

Opportunity is not the only spacecraft currently exploring the Red Planet. NASA's Mars Reconnaissance Orbiter was launched on Aug. 12, 2005, and is searching for evidence that water persisted on the surface of the Red Planet for a long period of time.

The agency is also launching a new car-sized rover to Mars in late November. The Mars Science Laboratory, and its centerpiece Curiosity rover, will land at the massive Gale crater to assess whether the crater is, or ever was, capable of supporting microbial life.

Meanwhile, Arvidson said the Opportunity rover has just kick-started a new chapter of its Red Planet exploration.

"It's a whole new mission."

You can follow SPACE.com staff writer Denise Chow on Twitter @denisechow. SPACE.com Managing Editor Tariq Malik (@tariqjmalik) contributed to this report. Follow SPACE.com for the latest in space science and exploration news on Twitter @Spacedotcom and on Facebook.