This is part of IEEE Spectrum's special report: Top 11 Technologies of the Decade
Pete Theisinger stands at the back of the mission control room, his round, mustachioed face frozen in a nervous grin. Hunkered down at long rows of computer consoles, his engineers sit on the edges of their chairs. NASA's Jet Propulsion Laboratory is hanging on the brink of a jubilant victory—or a devastating failure.
Then the black-and-white images appear on a big projection screen, and the room explodes in cheers. Some 200 million kilometers from Earth, a little robotic rover called Spirit, built here in Pasadena, Calif., has awakened and called home, sending images of what it is seeing. And what it is seeing is the rocky plain of Gusev Crater, in the southern highlands of Mars.
Wow, indeed. Since that night in 2004, Spirit and its twin rover, Opportunity, which landed three weeks later, have embarked on an extraordinary journey of discovery. Designing, constructing, launching, and landing those rovers on Mars has become NASA's most thrilling and successful planetary mission ever.
Why bother to study rocks and dirt from a cold, desolate, remote world? Because the geology of Mars embodies a history that should help unravel our own, and because those Martian rocks may also hold the answer to a question we've been asking ourselves for a very long time: Are we alone?
"Finding evidence that life arose independently on another planet would be one of the most profound discoveries that humans could ever make," Steve Squyres, astronomy professor at Cornell University and the mission's chief scientist, writes in Roving Mars (Hyperion, 2005), his candid account of the project. Mars, he adds, "is a world that can help us learn our place in the cosmos."
In the past decade, planetary rovers have emerged as one of the most amazing exploration tools humanity has ever seen. They have also fostered scientific and technological innovations that should find applications on Earth, in areas such as autonomous robotics, remote sensing, and materials engineering.
Above all, these robotic explorers have demonstrated that unmanned missions offer formidable rewards, with immensely smaller costs and risks than manned ones. Manned missions will surely remain on NASA's agenda; human boot prints on extraterrestrial soil are too powerful a draw to relinquish. But the success of the Mars rovers has proved that before we send humans, we ought to send robots.
NASA is not alone in advancing rover technology. The European Space Agency, in a joint mission with NASA, is building a next-generation Mars rover, called ExoMars, for launch in 2018. And other countries and even private companies have dreamed up rover plans of their own.
Right now, however, JPL is commanding all the attention. A new rover, the Mars Science Laboratory—named Curiosity in a contest—is scheduled to launch later this year. Compared to its golf-cart-size predecessors, it's a monster of a machine, the size of a Mini Cooper, weighing in at 900 kilograms, equipped with a nuclear power supply, and carrying 10 scientific instruments of unprecedented sophistication, including an advanced analytical system for detecting organic molecules. The mission: Determine whether conditions for life existed on Mars and were preserved—and if they were, find a sample.