It is obvious that Squyres knows all this, so why the dumbed-down rhetoric, where success is equated with proving a certain hypothesis? This is, in part, playing along with a certain line that NASA is using to package our current Mars exploration program. "Follow the Water" makes a fine slogan, and it does capture the essence of the questions of comparative planetology and habitability, both past and future, that form the core goals of our Mars program. Yet the actual motivations and strategies are never that simple. Given Squyres's admirable candor in addressing other aspects of NASA politics, I was surprised to see him uncritically adopt what seems like a simplified motivational mantra when describing the success criteria for his complex, multifaceted mission. Maybe he's just haunted by Lowell's ghost.
Squyres's book ends in September 2004, with Opportunity rooting among the sedimentary rock walls of Endurance crater, and Spirit steadfastly climbing up West Spur in the Columbia hills, where it has finally found some honest-to-goodness bedrock. I am hoping that next year there will be a paperback edition with the further exploits of the miracle rovers and their dogged, intelligent designers.
This article was originally published with the title Making Tracks on Mars.