THE PANORAMA OF GUSEV crater opened before them as they moved north across the rumpled, pitted floor that told, to a practiced eye, a story running back over billions of years. She watched closely the shifting scenery in its lurid pinks and rusty splashes, knowing she was seeing it for the last time. Somehow, each vista seemed fresh.The Mars Outpost program, starting in 2009, had left at the site several long-lived robotic scientific experiments, the Rover Boy, and a small chem plant that sucked carbon dioxide from the atmosphere to make methane and oxygen. Above the outpost orbited three communication satellites, supplying constant contact with Earth. With several more satellites left over for navigation and surveillance of the area, Earth had known just about as much about the Gusev Crater region as it could without putting people on the ground. Maps galore. But all that technology had missed the most important facet: the wonder of it.Nearly four billion years before, a huge asteroid had splashed into the crust here, opening a deep crater that nothing had been able to fill.
