NASA rover to land on Mars in August.

WorldWide Tech & Science. Francisco De Jesùs.

NASA rover to land on Mars in August.

LOS ANGELES (AP) Two months before NASA is set to land its most sophisticated rover on Mars, engineers on Earth are busy troubleshooting a nagging concern with the rover's drill that could contaminate rock samples gathered for study.

Project managers said Monday they were confident the rover nicknamed Curiosity will still be able to achieve its goals despite the hurdle.

For the past month, a team has been studying ways to get around the contamination problem, in which flakes of Teflon from the drill can break off and get mixed in with the rock samples. The effort so far has drained $2 million from the mission's reserve budget.

"It's not a serious problem because we see so many potential ways to work around this," said chief scientist John Grotzinger of the California Institute of Technology.

Curiosity is on target to land at Gale Crater near the Martian equator in early August. Instead of relying on airbags to land like previous Mars surface missions, Curiosity will be lowered to the surface on a tether and fire its thrusters to touch down. This never-before-tried landing technique has allowed scientists to zero in on the landing site.

Curiosity is now slated to land closer to a mountain in the center of the crater, which will cut down on the amount of driving it will initially need to do.

Project manager Pete Theisinger of the NASA Jet Propulsion Laboratory estimated this will save about four months of driving, allowing more time to study Martian rocks and soil.

The two-year, $2.5 billion mission seeks to determine whether the environment could have been suitable for microbial life. One of the main goals is to search for the organic building blocks of life using the most advanced toolkit sent to Mars.

Curiosity is a mobile science lab. The drill is located at the end of its robotic arm along with a scoop. It's designed to bore into bedrock and scoop up powdered grains that are then transferred to Curiosity's deck to analyze.

Tests before launch revealed Teflon from the drill can rub off and taint the samples. Some workarounds being considered include baking the samples so that the contaminant is separated out. The team is also pondering switching to a different, gentler drilling mode in certain cases.

In the worst case scenario, scientists may have to rely on the scoop to collect soil and Curiosity's wheels to crush rocks into bits.

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Follow Alicia Chang's coverage at http://www.twitter.com/SciWriAlicia .

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Online:

http://www.nasa.gov/msl