by Corey S. Powell
For at least the next five years, NASA's Cassini spacecraft, six tons ofbrute technology laboriously wending its way to Saturn and its giant moonTitan, will serve nicely as a bloated billboard with this message: The era ofbig, unmanned space missions is over. Not only did the craft's considerableheft force an impressively circuitous route that depends on the gravitationalpull of three heavenly bodies, but its $2 billion cost clashed ominously withthe U.S. space agency's shrinking budget.
Just as the extinction of the dinosaurs cleared a place for little, lithemammals, so the termination of huge missions like Cassini will createopportunities for petite but powerful explorers. Under strict orders fromNASA administrator Daniel Goldin, whose oft-repeated mantra is "better,faster, cheaper," the agency is moving toward ideas reminiscent of science-fiction novels--robots that could fit on a spoon, solar sails, and rockets nolarger than a computer chip. The technologies will be seen ...
