The Nation | COLUMN ONE

Kicking the Tires on Mars

An auto reviewer finds rover Spirit a bit pricey -- $410 million, with destination and delivery charges -- but enthuses it really shines off-road.

January 19, 2004|Dan Neil | Times Staff Writer

There is a saying in robotics: You shouldn't anthropomorphize robots. They don't like it.

Even so, it's hard not to think of the Mars Exploration Rover Spirit as a kind of gawky, geeky geologist moving in halting steps as it fitfully cogitates its path to the next interesting rock. All it needs is a pith helmet.

From my perspective as The Times' auto reviewer, I can tell you there is nothing human at all about Spirit.

It's a car.

Like any car, it has wheels. Yes, there are six of them, but a Ford "dualie" pickup has that many too. It's underpowered (about 0.06 horsepower), but so are many vehicles from India.

With a top speed of about 0.1 mph, the brains of an obsolete desktop computer and the power of two light bulbs, the rover is not what you would call a space Ferrari.

But to the men and women of the Jet Propulsion Laboratory, it's a screaming hot rod of interplanetary science.

"It's an awesome machine," said Spirit flight director Chris Lewicki. "It's the coolest set of wheels on Mars."

There are only two places in the universe to get behind the wheel of a rover. One is Pasadena, the other is Gusev Crater on Mars.

I opted for Pasadena, looking over the shoulder of rover operator Scott A. Maxwell at his keyboard cockpit as he rehearsed his first drives in the Martian countryside.

The rover is not a luxury vehicle. That's a galactic understatement. There are no heated seats, no in-car DVD player, no tinted windows, no refrigerated glove box. You have to buy a Saab for that.

For a stripped-down model, it's a bit on the expensive side -- about $410 million, with destination and delivery charges to Mars.

The first problem with driving the rover is that you can't actually drive it. Mars is far away: 100 million miles, or 8.9 light-minutes. To send a message and get a reply takes, at best, about 20 minutes.

The delay means that Spirit, which rolled off its lander Thursday, cannot be "joysticked," that is, controlled from the ground in real time. The Soviet Lunakhod moon rover -- a mere 3 light-seconds from Earth -- required a five-man team to tele-operate, and it was a handful.

"That time delay really messes us up," said Brian Cooper, one of the rover controllers.

Spirit and its twin, Opportunity (scheduled to land on Mars on Saturday), are point-and-shoot machines. They are imbued with a large degree of autonomy, designed with their own decision-making software so that they may be at home on the Martian range.

What rover operators do is throw a lawn dart icon at a computerized map of Mars, marking the destination the science team back at JPL has picked out. Think of it as NASA's version of the OnStar system.

Then, using its complex terrain visualization and guidance system, Spirit will traverse on its own to the target through a series of "way points."

"We tell it: 'You can get to this spot, and we don't care how you get there and we don't care what your final orientation is,' " Cooper said.

It's kind of like driving a Hummer in Los Angeles.

The Hummer, at least, has headlights. The rover needs three sets of black-and-white navigational cameras to see where it's going. One set of navigation cameras is on top of a mast, and two sets of hazard avoidance cameras are on its "bumpers."

The three-dimensional images created are processed in two ways: human 3-D, the kind of stereoscopic images familiar from cheesy horror movies; and machine 3-D, a swarming cloud of data points that model the contours of the terrain.

The human 3-D images are fed into special LCD goggles -- high-tech versions of those "Night of the Living Dead" specs -- that help drivers visualize hazards on the surface.

"It looks like you are walking on Mars," Cooper said.

Maybe, but in the dim control rooms of JPL, the rover drivers in their dark shades look like jazz musicians grooving on a cosmic melody.

But even the most data-rich terrain map can be treacherously incomplete because Spirit cannot see behind rocks and obstacles. It's like driving through the desert at night. The long shadows cast by rocks and brush are analogous to the hollows of incomplete data.

"The problem is that neither the rover nor the human planners on Earth can see very far away," said Mark Maimone, a space robotics expert at JPL. "It sees pretty well 10 to 20 meters out, but it falls off after that."

As a result, it's easy for the rover -- and its backseat drivers at JPL -- to get disoriented, as if it were navigating an unfamiliar city at night.

To keep track of its position, Spirit is equipped with an inertial measurement unit, the same hardware that helps tell an F-16 pilot which way is up.

"It's really quite challenging in the Mars-like terrain to keep a good idea of your position and which way you're pointed," Maimone said.

So let me get this straight: You can't really drive it. You can't really see out of it. It's overpriced. It's like driving a Lincoln Town Car.

Now that Spirit has rolled onto the surface, the engineers and scientists are eager to put the pedal to the metal.

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