The next generation Mars rover

The other half of the building is a spartan, spotless, brightly lit "clean room" designed to be dust-free. In the center sits a shiny gold and silver rover, the size of a dinner table and the object of much of Bob Anderson's affection: The Mars Exploration Rover, dubbed MER.

"This is our baby," he says, circling the full-scale model and pointing out its features. A high-gain antenna that will communicate directly with Earth. A 360-degree camera that will see in visible-light color as well as infrared.

Anderson saves his favorite stuff, the tools, for last.

"And here's the instrument arm. Five degrees of freedom. And all the instrument packages." He lifts up the instrument arm -- hinged as though at an elbow and wrist -- and points to the thing he's been dying to point to for an hour now.

"Here's the RAT. Rock Abrasion Tool."

Of course the real RAT isn't attached yet. Like everything this rover will carry to Mars, the RAT is still being designed. He then rotates the model's arm and shows where a microscopic imager will hang. "You know, like a geologist, when they go into the field and crack a rock? And then they'll take their hand lens and take a look? This is our hand lens."

In addition, the instrument arm will host a pair of spectrometers to determine a rock's mineral content. It might not be as good as putting Bob Anderson on Mars, "but we're getting close," he says.

Get this bird to the Cape

The Mars Exploration Rover program will involve two identical rovers both scheduled for launch in June of 2003. They will land in two different locations on Mars early the following year. The landings will be similar to Pathfinder -- parachutes will slow the crafts and airbags will cushion the impact. Imagine giant beach balls bouncing across the surface a dozen times.

Once settled, the airbags will deflate, a series of petals will open up, and the rover will drive off. Unlike the Pathfinder/Sojourner pairing, the MERs have no mother craft to report back to and so carry all of their instruments with them.

The successful rollout of the pair of 300-pound rovers on Mars will be an important time for JPL. Because the Mars Polar Lander mission failed in 1999, the MERs will be the first spacecraft to land on the Red Planet since 1997.

And it won't be easy.

"This is a very tough mission to do," says JPL Director Charles Elachi.

It is a mission that no one but JPL could pull off, Elachi says, an example of the sort of pioneering we can expect to see more of as he works to refocus the organization's efforts on selecting projects that are "almost at the edge of impossible."

A question hangs in the pure air of the clean room, above a full-scale model of the heaviest and most complex Mars rover ever conceived, one that will double as its own landing craft -- an approach that's never been tried before.

Anderson, arms crossed, begins answering the question before it is fully asked.

Are you afraid?

"Not at all."

Is it going to land?

"Absolutely."

Aren't you even concerned about getting it properly through the Martian atmosphere?

For the first time all day, Anderson sidesteps a question. He knows that's where Mars Climate Orbiter had trouble. Perhaps as with many JPL employees, the emotional wound is still festering. Some describe the disappearance of that craft, and also of the Mars Polar Lander, as akin to losing a loved one.

Or maybe Anderson just knows that insertion into orbit is one aspect of the mission he has no control over. Someone else's worry.

"I think our biggest concern right now is schedule, and getting this bird to the Cape."