This year, when it came to producing excitement--among the public and jaded journalists alike--one entrant to the Discover Awards seemed to stand not only apart from the others but also a bit above them. From the standpoint of ingenuity, imagination, and sheer fun, the editors of Discover could not think of anything that equaled Pathfinder, the spacecraft that landed on Mars last July Fourth, and Sojourner, the robotic rover that went along for the ride. These days it's not enough merely to go to a planet, you have to do it on a shoestring. Pathfinder and Sojourner together cost less than $200 million, a pittance. "The challenge was beyond belief, like no other space project," says a breathless Tony Spear, the head of the Pathfinder project at the Jet Propulsion Laboratory. "Not only was landing on Mars tough, but we had to do it for a fixed cost and to a tight schedule." In their quest to maximize bang per buck, Spear and his colleagues were not afraid to eschew tried-and-true (and very expensive) retro rockets in favor of a slightly less conventional method of landing. Pathfinder went careering into the atmosphere like a meteorite and bounced around on the surface like a beach ball.
When the lander came to rest, it opened like a flower and out crawled Sojourner, a two-foot-long erector-set-toy of a robotic rover--the first to operate on a planet other than Earth. Sojourner was designed for a life of seven days, but it carried on for nearly three months, pointing its alpha proton X-ray spectrometer at rock and soil samples and sending back data on their chemical composition, before fading into radio silence. "We were ecstatic with the performance of Sojourner," says Jake Matijevic, head of the Sojourner project at JPL.
For the JPL team, one of the hardest parts of the mission was refraining from engineering it to perfection. "We didn't play around as much as we did in past missions, analyzing everything to death," says Spear. "We'd get the hardware together as fast as we could and then test the daylights out of it." The result--the slapstick landing, the comically cautious rover--brought new meaning to the phrase "elegant engineering solution." But it worked, and it had charm and personality to boot. When was the last time the entire country was glued to the television set eagerly anticipating pictures from outer space? Perhaps the best thing about the mission was that it reinterpreted that old can-do spirit of nasa's early days for our more pragmatic times. Not only did it inaugurate what promises to be a spate of planetary missions to come, it reminded us that Mars is indeed another world, and that all it takes is a leap of the imagination to see it beckon.