IT WAS supposed to be a 100-day mission to a planet that eats spacecraft for breakfast. But NASA’s twin rovers, Spirit and Opportunity, have now spent two years toddling around the frigid wasteland that is Mars. They have survived more than seven times as long and driven 10 times as far as they were designed to. To match this feat, the Hubble Space Telescope would need to remain in orbit for another 55 years.
The rovers are not just successful, they are outrageously so. With the next rover mission already under development, it is worth asking why Spirit and Opportunity…
