Engineers are spinning their wheels on the red planet, getting a driving lesson in steering the Opportunity Mars Exploration Rover at Meridiani Planum.

The robot fell short in wheeling toward an exposed rock outcrop, perhaps due to soil slippage Friday. Rover operations at the Jet Propulsion Laboratory (JPL) in Pasadena, California plan to complete the drive to the exposed rock on Saturday.

Prior to tomorrows drive, itll be a "touch and go" day for Opportunity, Wallace said. The rover will flex its instrumented arm, reaching down toward the martian soil.

Another set of pictures are to be taken using the arm-mounted Microscopic Imager. Scientists want to continue to catalog the soil inside the crater in which Opportunity is driving over, Wallace said.

Once the arm is re-stowed, the robot is to finish its trek to Snout. Opportunity will then study in detail the selected rock outcrop section, making use of a suite of science tools.

"From there it looks like the scientists are asking us to start an arc along the bottom of the outcrop area," Wallace said. The rover will make a progression of short drives parallel to the rocks, stopping for science at choice spots.

Wallace told SPACE.com that the cause of Opportunity falling short its destination is not entirely clear. "Im pretty sure what were seeing is soil slippage," he noted.

The robot is climbing up the side of the crater, now pitched up by almost 13 degrees, Wallace said. "Everything is kind of pointing to the idea that were getting somewhere between 10 to 20 percent of slip during these traverses."

Given a better understanding of what type of soil Opportunity is wheeling across and how those wheels handle that soil, rover operators should be able to adjust to the situation, Wallace said.

"The rover continues to operate nominally. Shes healthy and happy and continues to do the job she was sent to do," Wallace said.