INSIGHTS
October 2004 issue

Father of Spirit and Opportunity

But neither problem has detracted from the science that's been done. "It's fair to say that the rovers would certainly have not been as successful as they are and possibly would never even have happened if it wasn't for Steve," says Jim Bell, lead scientist for the panoramic cameras on both rovers and a close colleague of Squyres' at Cornell. To him, Squyres has set the example for those leading future missions. You not only "have to be a top-notch scientist," Bell states, "but you also have to be willing to get head over heels into the design of the instruments."

The most important discovery is the evidence for great amounts of water at Meridiani Planum. Opportunity detected, for instance, sulfate salts and hematite concretions--small, grayish, iron-containing spherules that scientists have been calling "blueberries." And as Squyres had wondered, shavings of the ratted rock in the crater were indeed brick-red, typical of hematite when it is pulverized. Sulfate and hematite are left in rocks by water, so they suggest that Opportunity is working on what was once the shoreline of a salty sea, although clues gathered so far do not indicate how long, or how long ago, liquid water covered the area. "Not only did we find evidence for a habitable environment at Meridiani," Squyres remarks, "but we've got these wonderful geologic deposits--sulfates and in particular the hematite concretions--that are very good at preserving evidence of whether there was interesting organic chemistry, whether there was life."

It's unlikely the rovers themselves will directly discover signs of life, though. Instead they are laying the groundwork for a sample-return mission, by robots or someday by humans. Squyres is all in favor of a manned mission to Mars. "I'm a huge fan of sending robots to Mars, obviously--that's what I do for a living. But even I believe that the best exploration, the most comprehensive, the most inspiring exploration is going to be conducted by humans."

Although some argue that NASA's many successful robotic missions prove that costly human flights are unnecessary, Squyres doesn't buy it. "I think people who would point to the successes of these two rovers as evidence that you don't need to send humans to Mars are missing the point entirely. I view our rovers not as competitors to humans but as precursors. And they're precursors in the sense of telling us more about the Martian surface and what it's like, what it takes to walk across it, build on it, launch from it, that kind of thing." A human base on Meridiani Planum, now being explored by Squyres and his MER team, would be a good place to start.

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David Appell is based in Newmarket, N.H.

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