Curiosity rover prepares to drill on Mars

Scientists have zeroed in on a Martian target for the Curiosity rover to drill into: A rock outcrop as flat as a pool table that's expected to yield fresh insight into the red planet's history.

Running a tad behind schedule, Curiosity was due to arrive at the site in the next several days. After an inspection of the surroundings, the car-size rover will test its drill for the first time "probably in the next two weeks," project manager Richard Cook of the NASA Jet Propulsion Laboratory said Tuesday.

The highly anticipated drilling has been billed as the most complex engineering task since the acrobatic landing inside a Martian crater last summer. Curiosity is on a quest to determine whether environmental conditions could have been favorable for microbes.

By boring into a rock and transferring the powder to the rover's onboard chemistry lab and other instruments, scientists should get a better handle on the region's mineral and chemical makeup.

"We're thrilled, and we can't wait to get drilling," said project scientist John Grotzinger of the California Institute of Technology.

First samples from Mars interior

Previous rovers Opportunity and Spirit carried a grinding tool that peeled away rock layers. Curiosity is capable of drilling down several inches to collect a sample from the interiora first on Mars.

Opportunity is still operating on the surface of Mars, but Spirit lost contact with Earth in 2010.

Since the $2.5 billion Curiosity mission launched in 2011, engineers have been troubleshooting an issue with the rover's drill in which flakes of Teflon can break off and get mixed with the rock samples. Cook said the contamination should not affect the mission.

"We are reasonably confident that it's something that we'll be able to work our way around," he said.

As the most high-tech interplanetary rover, Curiosity has been on a slow streak since its action-packed arrival. Grotzinger said the pace of the mission was "100 percent discovery-driven" and can't be rushed.

Already, Curiosity has lingered longer than expected at its current location because scientists have been captivated by the sedimentary rocks that differ from the pebbles found at the landing site. After some last-minute studies, the rover will head to the rock outcrop dubbed "John Klein" after a mission team member who died in 2011.

Curiosity's ultimate goal is to drive to the base of Mount Sharp, a six-month journey with no stops. The plan is to begin the road trip after drilling is complete with pauses along the way.