A shiny six-wheeled robot lumbers through reddish sand, cautiously studying the rocky, dusty landscape with stereo eyes. Boulders are everywhere, each a potential storehouse of information or an obstacle to be avoided. A hidden ravine could spell a quick end.

The mechanical geologist lurches forward tentatively, thinks about where it has been and ponders how best to go where it's told, based on commands beamed to its antenna from Mission Control back at the Jet Propulsion Laboratory in Pasadena.

Meanwhile, huddled around a JPL computer, Mars experts from all over the world struggle to help the robot safely reach its destination, a certain rock where the rover will stick out its multi-purpose exploratory arm and drill in, looking for evidence of water and life. But the engineers and researchers are clueless as to the rover's whereabouts. They would desperately like to get a fix on its location.

Poring over a satellite image of the desolate area, one of the scientists spots a long, straight, dark line. Something familiar about it. Almost civilized.

"I've driven that route to Vegas a lot!" he finally blurts out.

For Bob Anderson and a handful of colleagues on location in California's Mojave Desert, the game is up. But Anderson laughs it off. "Scientists are smart," he says, and perhaps anyone who'd driven it could have picked out Route 15 on the satellite image.

The rover is, of course, not on Mars but out here in a somewhat similar environment, undergoing a 10-day "blind" test in early May to help researchers fine tune a design that will launch in 2003.

The RAT Man

Bob Anderson is a JPL geologist charged with training engineers and software designers, as well as Mars rovers, how to think like geologists. The robots, in turn, will be expected to teach us about the Red Planet.

It's a hot day in early June, and Anderson is huffing and puffing. He has just hoofed it up a steep hill on the JPL campus, climbing only a block or so from his office to the outdoor Mars Yard, but it's a walk that leaves one breathless in these steep hills above Pasadena. Anderson is wearing shorts and sandals, a white golf shirt and sleek black shades. This is JPL, not IBM.

He sits down, takes a breath, and introduces himself.

"I'm the RAT man." A smile sneaks across his face, like a rap fan who personally knows Eminem. Then realizing his current audience might not be up on the latest jargon, he adds, "Rock Abrasion Tool?"

The Rock Abrasion Tool, or RAT, is the most advanced geological tool ever to go to another planet. If all goes well, scientists will for the first time be able to actually drill into a Martian rock and analyze its composition. If there are fossils or other signs of life in the rock, the RAT and a host of devices hanging on the same swiveling instrument arm stand a decent chance of making one of the most important discoveries in the history of science.

Or, as Anderson well knows, we might just learn a whole lot about Martian rocks.

The Mars Yard

Bob Anderson figures he's got just about the coolest job in the world.

"C'mon, look what I'm doing?" he says. "I come to work and I play with toys. I get to drive cars on the surface of Mars. I get to see things that --." He pauses, thinks about the first images returned by the Mars Pathfinder mission in 1997, then continues, " -- that nobody sees."

Of course, much of what Anderson saw was later shown to the rest of the world. The wildly popular Pathfinder mission, with its cute little Sojourner rover, landed on the cover of Time magazine. And the first color panoramic views of the Red Planet enthralled a burgeoning population of Web surfers.

The only thing that could have been better for Anderson is to have gone to Mars himself. The mere thought of it generates a colossal exhale and two words: "Oh, awesome."

But Anderson doesn't expect to personally crack open any red rocks. There is too much to learn first, too much we need to understand about Mars, as well as long-term space travel, before we send humans.

So he leads the way into the Mars Yard, a block-sized outdoor sandy lot where remote-control geologists are first tested.

Against a panoramic Red Planet backdrop that has been painted on cinderblock walls, mockups of rovers past and future creep across a boulder-strewn faux Martian landscape, struggling to wheel their way toward boulders marked by small red flags. The robots' tracks tell tales of success and failure. Some flags reached, some flags surrounded by undisturbed sand.

An adjacent trailer, cramped, colorless and somewhat aged, would have looked right at home in a forlorn lot on the edge of the Mojave. But here in the high-tech hills above Pasadena, 15 miles from Hollywood at one of the world's hotbeds for robotic research, it seems especially cheap. Yet the trailer signifies an approach to science that pervades the university-like place known as JPL: Beg, borrow and, er, somehow get your resources as cheaply as possible to build the best damn mock-up you can. Then put the real money into the finished product.

Somebody's old bathroom sink hangs on the outside of the trailer. Inside, eight computers sit on small desks, which leave little room for passing through. At one end, a tiny indoor sandpit is home to three of the world's most advanced robots, including a sister to the Sojourner rover now abandoned on Mars.

Under a dull, claustrophobic, 7-foot ceiling, lessons learned in the Mojave tests are written into fresh computer code. Knobs are tweaked, hinges redesigned. Solar-panel shapes are rethought.

The greatest Mars rover ever is being conceived.

Next Page: Not so fast -- We have problems here!