If the Nobel judges gave a prize for over-achievement, a good candidate might be a six-wheeled, breadbox-sized robot named Sojourner. As robots go, the rover that explored Mars last year was a modest contraption; it traveled only about two feet a minute and performed just two simple scientific operations, photographing rocks and reading their chemical signatures. And the machine cost just $25 million, with the Pathfinder mission that carried it to Mars a bargain at $266 million, a quarter the cost of a single space-shuttle flight. But Sojourner was the Energizer Bunny of robots, the rover that just kept on roving. Officials cautiously projected that it might operate for a month on Mars; it sent back data for three.
It also seized the public imagination as no space venture had since Neil Armstrong and Buzz Aldrin planted the United States flag on the moon. In the mission’s first heady weeks, NASA’s multiple Pathfinder World Wide Web sites recorded about 45 million hits a day. Time and Newsweek accorded Pathfinder’s July 4 landing and Sojourner’s subsequent debarkation simultaneous covers and the sorts of spreads usually reserved for the starts of wars or the deaths of princesses. Mattel immediately sold out the first run of its Sojourner “Mighty Wheels” toy. At a midsummer reception, Vice President Al Gore joked that he had “been replaced by Sojourner as the world’s favorite robot.” Had humankind ever identified so closely with
Thus did the rover and its faithful lander save NASA from the stigma of two decades of costly boondoggles, fatal disasters, and dashed expectations. The essential strategy of the reformed NASA-nix the costly, dangerous manned expeditions and let robots and other remote exploration tools do the work-had panned out.
That was just the start. NASA is now preparing succeeding generations of planetary explorers that will make Sojourner look decidedly humdrum: rovers to traverse many miles of Mars’s expanses, gathering far-flung samples for transport back to Earth; “penetrators” to probe the living worlds that might lie beneath extraterrestrial rock and ice crusts; and “aerobots” to survey other planets and their moons, from Venus to Jupiter’s moon Titan, and perhaps even Uranus and Neptune, from the air.
As exotic and wildly varied as these devices may seem, they all derive from the same critical change in NASA’s approach to unmanned planetary exploration nearly nine years ago-“faster, cheaper, better.” This change was initiated not through official NASA policy but in defiance of it, by a small group of robot-building heretics who saw a better way to go to Mars than their bosses saw and who worked covertly to make the idea possible. Appreciating the roots of that robot-building rebellion helps in understanding why planetary exploration is now taking the course it is.