Researchers test Mars rover prototype in Nevada desert

Matthew Fordahl

Sunday, June 11, 2000 | 2:01 a.m.

BLACK ROCK SUMMIT, Nev. - The six-wheeled rover inches over the gravel of a wind-swept hillside, carefully avoiding boulders and precipices in a slow-motion hunt for a rock that struck the fancy of distant planetary scientists.

But there's a problem. One of the steel-cleated wheels is dragging like a broken shopping cart, and the engineers in Pasadena can't figure out what's wrong. They beam commands to budge the faraway robot back and forth, left and right. No luck.

A voice finally crackles through a speaker in mission control: Try the belly camera to check for obstructions - such as the rock lodged under a wheel.

The planetary rover named FIDO is soon on its way.

If FIDO had been on Mars, the troubleshooting would have wasted valuable hours. This time, the rover was being tested in desolate central Nevada, a spot that rivals Mars in emptiness but can support space-age driving instructors.

"You don't want a $200 million mission to Mars to be the first time you've tried the rover," said Kris Larsen, one of the shivering researchers at Black Rock Summit and a graduate student at Washington University in St. Louis.

Larsen and about a dozen other researchers spent two weeks in May baby-sitting FIDO and a companion named K9 in the shadow of the Pancake Mountains, about 90 miles between Tonopah and Ely.

Their mission was to monitor the coffee table-size robot as it was controlled by satellite from NASA's Jet Propulsion Laboratory nearly 400 miles away. Several rock-sniffing and scraping science instruments also were tested.

Though FIDO and other prototypes will never see the surface of Mars, their experience on Earth will be incorporated into future rovers such as Athena, which could fly in a mission as early as 2003.

NASA is expected to announce plans for that mission next month. Earlier, the agency confirmed it would choose between a large orbiter or a surface rover that would land using large airbags - the same as Mars Pathfinder in 1997.

The decision will end months of uncertainty following last year's failures of Mars Polar Lander and Mars Climate Orbiter.

"We went from being planned for the 2003-2005 missions to not being planned to being a prime contender for 2003," Larsen said. "We stand a really good chance of going to Mars in the next few years."

NASA spent about $1.2 million to build a half-dozen rover prototypes, which were constructed at the JPL of mostly off-the-shelf parts and mundane metals such as aluminum. Rovers bound for Mars would be much more expensive, as they must be made to withstand the rigors and radiation of space.

To add to the realism of the Nevada test, mission navigators in Pasadena did not know the rover's location except that it was somewhere in the United States. They had to image the area, plot the course and find interesting rocks.

Nobody sits in the control room with a joystick as it would take 20 minutes for a signal to reach Mars millions of miles away. The rover's commands are planned out in advance and then beamed to the planet.

The sequence codes consist of the positions of various objects and directions. But the robot must be somewhat intelligent: Controllers tell the rover where to go; it's up to the machine to figure out the best way to get there.

FIDO, which stands for the Field Integrated Design and Operations rover, is about the size of a St. Bernard, roughly twice as large as the Sojourner robot that roamed the Red Planet in 1997. Aside from size, FIDO carries a strong family resemblance.

The larger robot can drive for miles, as opposed to the 330 feet traveled by Sojourner during its mission. FIDO's 8-inch wheels can drive over rocks 12 inches tall, as opposed to the 6-inch obstacle barrier faced by Sojourner.

Sojourner also stopped every 4 inches to survey its surroundings, but FIDO's eyes can detect obstacles up to 5 feet ahead. And though the larger rover is no speed demon at .13 mph, it's about 10 times faster than Sojourner.

"FIDO keeps a history of where it's been, so if it gets into an area where it's trapped, it knows how to back out safely," said Terry Huntsberger, a senior JPL technical staff member. "The safety aspect is the most important thing."

An icy wind blows though a canyon not far from an ancient lava flow. FIDO's electronics hum softly behind a ridge several hundred feet away from the trailers, satellite dishes and portable toilets where the researchers set up camp.

Last year's tests took place in California's Mojave Desert, outside Baker. This time, researchers wanted to focus on some of the rover's science instruments, so they selected the geologically interesting but isolated Black Rock Summit.

"We chose the location because it's sort of remote - so you don't have a lot of people poking around. And it's pristine - it's not going to have trash blowing through the scene," Larsen said.

Lava flowed through the area about 100,000 years ago and minerals in the area were weathered by water. Similar findings on Mars would be a major discovery in the search for past or present life because water is such an important ingredient.

"This would be the ideal kind of rock to find on Mars," Huntsberger said. "It's a smoking gun."

Huntsberger and his JPL engineer Brett Kennedy watch the clouds carefully for any sign of rain that could cut short this day's mission - running commands created by a group of Dutch high school students who won a competition.

For more than two hours, the two wait next to the motionless machine, occasionally radioing the camp to find out what the delay might be. The students, who are at JPL mission control, are reworking their commands.

After waiting for two hours, the sequence from Pasadena is finally received by the control trailer and is instantly relayed by a relay antenna to the rover humming motionless behind a ridge.

Almost imperceptibly, the mast begins to rise to take pictures of the landscape. Fully extended, it reaches more than two meters above the flat top of the rover's solar panels.

A few minutes into the sequence, sprinkles begin to fall. Kennedy and Huntsberger grab a gold tarp and cover the machine's sensitive electronics.

The mist turned to rain.

"Abort the sequence," Huntsberger radios to the control trailer.

After a change of batteries and a break in the rain several minutes later, the rover springs back to life and carries on its mission of science and manages to return to its home base on a mock lander planted at the top of the ridge 100 feet away.

Even in the middle of nowhere, the enterprise attracts some attention.

Today, Rosie Garaventa's class of five schoolchildren arrives unannounced from the Duckwater Shoshone Indian tribe. They quickly gather around the rover as Kennedy points out its features.

"Instead of four wheels and four-wheel drive. We've got six wheels and six-wheel drive," he said." Not only can we turn how a car would turn, but we can actually turn all the wheels in one direction, and we can drive sideways if we want."

He shows the robotic arm, the cameras and miniature drill. He points to the lowered masthead and the camera that resembles a roll of paper towels on a holder. The children edge closer as he pops up a panel on the solar cells, revealing its the electrical guts.

"What do you guys think?" he asks.

"Cool!" the children chime.

"Got any questions?" he asks.

"What does it do?" 8-year-old Odome Jackson asks.

The children eventually leave, and Kennedy and Huntsberger resume their long wait for another set of sequences to be downloaded. Next year, the rover team could find itself in an even more remote area.

"They're threatening Antarctica next year," Larsen said.

For more, see these websites:

On the Net: NASA's Jet Propulsion Laboratory: http://www.jpl.nasa.gov

FIDO home page: http://wufs.wustl.edu/rover/