The U.S. robotic Mars rover has completed its first drive across the dusty Martian terrain. The Spirit rover drove about three meters to approach a nearby rock for closer inspection.

The Spirit rover completed the short trip in about 30 minutes, occasionally stopping during the journey to snap pictures. It was the rover's first trip away from the landing platform since its six wheels first rolled onto Martian soil last week.

Mission Mobility Engineer Eddie Tunstel says the trip was a chance to test Spirit's traction and steering on the planet's loose soil.

"This is our first drive. So, we're saying to ourselves, well, okay, let's test this new soil, let's see what this traction is like, let's see what this mobility system does in this new terrain. And this is the sort of baby steps we're taking, in order to arrive at those conclusions," he said.

The rover spent the last few days testing some of its instruments, while scientists decided which nearby rocks were good candidates for tests. They selected a triangle-shaped rock that they named Adirondack. Scientists say the rough, tan colored rock looks like a familiar type of volcanic rock called basalt.

Mission Researcher Dave Des Marais says Adirondack's size and possibly familiar composition make it a good candidate for the Spirit's first tests. "Like I say, nice, clean, flat surface, get the tools checked out, how do these tools actually work on Mars? They worked great on earth, and I think they're working great so far on Mars. (The question is) how do they work on a rock that we think we probably know what it is? So, I think from an analytical point of view, it is a good place to start," he said.

The rover will soon begin examining Adirondack with a microscopic imaging camera and two other instruments that work to determine what minerals and elements make-up the rock. After those tests are completed, Spirit will use a grinding tool to erode the rock's surface and observe its interior.

Mission Manager Mark Adler says the rover's twin, named Opportunity, is right on schedule for a January 25 landing.

"Right now, it looks real good, it looks like we're not going to have to do any more maneuvers on Opportunity and it's pretty much good to go [(ready for landing]," he said.

Opportunity carries the same scientific instruments as Spirit, but it is headed to the opposite side of Mars, to terrain expected to be much different from the crater Spirit is exploring. If all goes well, both rovers are expected to spend at least 90 days looking for signs of water on the Martian surface.