Sojourner, the most lovable and heroic extraterrestrial since R2D2, began its historic reconnaissance of Mars over the weekend - leaving indelible marks in the dust of the Red Planet and on human achievement in space.
The one-foot-tall geologist, a high-tech dune buggy, immediately started sniffing out detailed information of a boulder-strewn world 119 million miles away - the first step in what scientists hope will become a turning point in the search for life elsewhere in the universe.
Sojourner's rovings, at the deliberate pace of a half inch per second, as well as the novel bounce landing of the Pathfinder spacecraft on Friday have proved - so far - to be a triumph of technology and scientific endeavor.
Indeed, the first pictures relayed of the surface of Mars in 21 years, revealing an ocher terrain that looks like an uninhabited Tucson, Ariz., enthralled a nation otherwise preoccupied with finding a beach towel. They were a stark counterpoint to images of Russian cosmonauts toiling in an underwater tank over the weekend, trying to simulate repairs to the hobbled space station Mir.
"We're verging on near miracles," says Tony Spear, project manager of the Mars mission, in reviewing a weekend of textbook landings and crisp images.
Since it rolled from its resting place on the lander and became the first rover on the surface of Mars, Sojourner has begun gathering information on the chemical composition of nearby soil and rocks. Poring over the data coming back, "the scientists are in heaven," says mission manager Richard Cook.
Sojourner's early success was particularly meaningful to mission scientists and engineers because of initial complications. After an early glitch, they restored nearly full communications between the rover and the lander, which serves as the vital relay link with controllers on Earth.
The periodic rounds of hugs, high fives, and even tears that spread through mission control, however, signaled more than a technological success. They also heralded a changing of the guard. Not since the days of Apollo, old-timers say, have twenty- and thirtysomethings had such high-profile positions - from lead flight controller and rover driver to the engineers responsible for image-processing.
"This is a blast!" says Jennifer Harris, lead flight controller for the mission. Working toward her master's degree in aerospace engineering at the University of California at Los Angeles, the former missionary has a headline-making mission to tack on to her resume.
"I bet their parents don't even know where they are," quips one JPL veteran.
NASA officials say they hope that young talent and young-thinking talent, unhampered by preconceived notions about what it takes to pull off a mission, will provide the intellectual horsepower for their "cheaper, faster, better" approach to exploring the solar system.
For Pathfinder, "we gathered bright young people, put them together with a few crusty old veterans, and let them do their thing," says Wesley Huntress, associate administrator at the National Aeronautics and Space Administration. "The crusty old group has stayed in the background."
To some team members, the mission's success has been bittersweet. "I'm a little sad. This marks the end of my job with Mars Pathfinder," says Pieter Kallemeyn, lead engineer for the navigation group that shepherded Pathfinder during its seven-month voyage. He is moving on to plot courses for future Mars missions.
During the next several days, the exploration team of Pathfinder & Sojourner will conduct experiments ranging from chemical analysis of soil and rock samples to providing engineers with data to help design future rovers. Although the basic mission calls for seven days of activities for the rover and 30 days for the lander, mission officials expect the hardware to last longer. They're funded to run it for up to a year.
Ironically, the star technology in the landing - a cocoon of air bags that cradled Pathfinder to its final, bouncing finish - will not be used on future missions, even though the system has won over some critics. "If one had asked me five years ago, I would have said I don't believe it will ever work," says Jim Martin, project manager for the Viking landers. "I'm now a convert."
Planners expect landing sites for the next Mars missions to be smoother than that for Pathfinder, so future landers will follow Viking's lead of using small rocket engines to ease the lander to the ground after reentry and parachute descent.
ALTHOUGH the main scientific show takes place this week, some science experiments began even before Pathfinder landed. For example, devices on the craft that measure changes in acceleration kept tabs on Pathfinder's descent. The information has allowed researchers to see how the density of the Mars atmosphere varies with altitude.
The bulk of the instruments aboard Pathfinder and Sojourner are aimed at learning more about the planet's geology and atmosphere.
A stereo camera aboard the lander supplies 3-D images of the lander's environs for plotting Sojourner's travels. Its color filters will also help geologists classify rocks and determine how they've weathered. The camera, too, will be used for rudimentary astronomy from Mars. The "eyes" are roughly as sensitive as human eyes. Among its targets: Mars's moons, Phobos and Deimos. The camera will be used to measure the level of dust in the atmosphere as well. Other instruments will relay information on Martian weather.
But the star attraction on this mission is Sojourner. Because radio signals take 10 minutes to reach Mars, the rover is designed to find its own way to a set of destinations that the lander relays from controllers on Earth. When it reaches a rock geologists find intriguing, Sojourner places an X-ray spectrometer against the sample, which measures chemical composition.
The process takes about 10 hours. "We may only be able to analyze two or three rock samples" during the rover's seven-day mission, says Rudolph Rieder, a principal investigator.