Rover Rolls Onto Martian Soil After Overcoming Glitch

After a frightening 12-hour silence when the little Mars rover Sojourner refused to communicate with its mother ship, its modem finally responded to commands, allowing the 1-foot-high geologist to roll off its rear ramp onto Martian soil late Saturday.

“Life is complete,” said Rob Manning, chief flight engineer for the mission.

It is the first time a moving vehicle of any kind has crawled over the surface of Mars--and a critical moment in the search for life on other worlds. The successful deployment was a fitting sequel to the Pathfinder spacecraft’s spectacular Fourth of July landing on the Red Planet. Cautiously picking its way down a 20-degree angle toward a smooth, salmon pink patch of Mars, the rover was expected to begin its scientific investigation of the soil at the base of the ramp almost immediately, putting its sophisticated “nose” to the ground to analyze elements in the ground.

Early weather reports from Pathfinder’s newly deployed weather mast indicated that Mars is frigid cold--but otherwise hazy and still, with the tiny windsocks hanging straight down.

“We’re verging on near miracles, my wonderful team,” project manager Tony Spear said. He announced that the Pathfinder had been renamed the Sagan Memorial Station in honor of the late astronomer. “I wonder if Carl Sagan is smiling on us,” he said.

Responding to news that the modem was working again and the mission could proceed, rover coordinator Matt Wallace of NASA’s Jet Propulsion Laboratory, said, “It feels like we’ve been reinvited to the party.” Amid an otherwise flawless arrival on Mars, the rover developed a problem familiar to all on-line computer uses: Its modem wasn’t working. As the Earth set on Mars Friday night, before the problem was fixed, the rover was speaking to Pathfinder only in short grunts, like a grumpy teenager. “We’re just getting one syllable [at a time], not full sentences,” deputy project manager Brian Muirhead said.

After communications were restored, flight engineers called to each other: “The rover’s talking!” and “We’re alive! All right!”

It appeared that the Pathfinder had simply rebooted, or recycled as the engineers called it, itself over Friday night. “We’re a little perplexed as to what happened,” said Wallace, adding: “The spacecraft is fine.”

Engineers remained somewhat concerned that they didn’t know exactly what had caused the problem. “Until we understand [how it got fixed] we won’t know for sure what the cause was,” Wallace said. “But if it was correctable once, we feel there’s a high probability we could correct it again.”

All other systems on the rover and lander appeared to be working perfectly. By early evening, the small explosives had freed the cables holding fast the ramps, which had been curled up like rolls of aluminum foil. Then Sojourner stood up from its crouched position to its full 1-foot height, and freed itself from its base. Finally, it sauntered down to the surface at a stately pace of a half-inch per second.

The repair of the communications gap between the rover and lander was a great relief to the 100 waiting scientists eager to get their instruments on the rich rock treasures scattered over the Martian landscape.

“I hate to pat myself on the back, but this is the best place we could have possibly landed,” said project scientist Matthew Golombek, who was responsible for choosing the site. “When we saw those first images, 70 scientists were jumping up and down, cheering. I am the happiest person I could be.”

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Among the geological treasures waiting to be explored were rocks of all sizes and textures and colors, from a few inches to more than 10 feet high, layered, spotted, knobby, flat, round, white, blue, red, sandy and clumpy.

Golombek said the Viking landing of July 1976, NASA’s last visit to the Red Planet, was scheduled to set down in the same terrain. “They got scared away,” he said, because images taken from the Viking orbiter showed the landscape to be too lumpy for a safe landing. So mission controllers diverted the craft to a smoother site.

Good thing, said Golombek, because the Viking lander drifted down to the surface to stand on thin legs like an insect. “With those three spindly legs, it could have been curtains for Viking.”

Pathfinder was able to absorb hard knocks from sharp rocks because it fell to the surface encased in air bags constructed of four layers of bulletproof material. “What a way to [land],” said Golombek.

The great variety of rock forms and soil types at the site were exactly what the scientists ordered, Golombek said. One flat black form just on the horizon looked exactly like an analyst’s couch. Twenty miles or so away, twin peaks rose through the dusty pink haze. The foreground was strewn with huge boulders.

One grouping of large rocks leaned almost in unison toward the northwest, like a family of Martian pigeons. The fact that they were all slanting in the same direction suggested they were pushed over by flowing water, Golombek said. Water, hypothesized to have existed on ancient Mars, is a crucial ingredient to life.

Geologists believe that the Ares Vallis, where the Pathfinder landed, is the outflow of an ancient flood plain created when more water than is held in all the Great Lakes somehow pushed through the Martian crust in a two-week period--”the solar system’s largest flood,” Golombek said.

The gushing water carved out the valley in the process and collected a rich grab bag of different kinds of Martian rocks--perfect hunting ground for the rover. Liquid water disappeared from the surface of Mars billions of years ago for reasons that are still a mystery to scientists. Traces may still saturate strata deep beneath the surface, scientists speculate.

Equally interesting to geologists, the soil around the Pathfinder landing site appeared to come in at least three different colors, suggesting that some of it was probably native to the region while other patches were carried there by water and winds.

One rock had an almost flat shape, like a tabletop, while others rose in jagged peaks. The Pathfinder camera could also see the rim of a large crater several miles away, and an enormous boulder.

“We came very close to that rock,” said Peter Smith, who added that the Pathfinder could have been in “real trouble” if it had landed closer. In general, it is a far more varied landscape than Viking encountered, Golombek said. Some of the mountains in the distance appeared to be more than a 1,000 feet tall, and layers or strata appeared to be etched in some of the outcroppings.

It will be a while before the six-wheel rover gets around to exploring these intriguing surroundings. First, it will make a few practice turns to get accustomed to the territory.

“The first couple of days, we’ll just have a learner’s permit,” Wallace said. If all goes well, Sojourner will then begin a weeklong analysis of the Martian soil and rocks, beaming them back to Earth via relay with its mother ship.

Should the communications problem recur, the rover does have the capability to explore Mars on its own. It can find rocks, avoid obstacles and obtain scientific data. But without a link to a lander, it would probably not be able to communicate those findings back to Earth.

But thanks to Saturday’s successful repair, that now appears unlikely.