Weighing as much as a small car, a rover named Curiosity rolls quietly around Mars. Scientific instruments pack its body and cluster at the end of a mechanical arm. An arrangement of lenses and instruments tops its mast, like a face. To the many NASA workers involved in Curiosity's mission on Mars, the rover is not simply a robot, but an astronaut bravely exploring an alien place. Curiosity's instruments collect data and its cameras take images of the Mars landscape, including self-portraits, in vivid color and detail. As it roams and explores, Curiosity will help find the answers to such age-old questions as has there ever been life on Mars? Could there be one day?